Printer, printing method, program, and printing system

The present invention relates to a printing apparatus, a printing method, a program, and a printing system in which ink is ejected from a plurality of nozzles onto a medium to form dots.

An inkjet printer is known as a printing device that prints on various media such as paper, film, and cloth. This inkjet printer ejects ink toward a medium to form dots on the medium and prints an image. The inkjet printer is provided with a head that moves relatively along a direction orthogonal to the transport direction of the medium. The head is provided with a plurality of nozzles for ejecting ink toward the medium. The plurality of nozzles eject ink toward the medium when the head moves relative to the medium. As a result, dots are formed on the medium and an image is printed. An inkjet printer executes a printing process by alternately performing such an ink ejection operation and a transfer operation of transporting a medium in a predetermined direction (see Patent Document 1).<patcit num="1"><text>Utility Model Registration No. 3096490</text></patcit>

<p> However, in such a printing apparatus, the head may be installed at an angle with respect to the moving direction. This is caused by an error during manufacturing or when the head is attached when the head is removable. When the head is installed at an oblique angle in this way, there is a problem that the positions of the dots formed by the ink ejected from each nozzle are greatly deviated. Due to such a misalignment of the dots, the positions of the dots formed earlier on the medium and the positions of the dots formed later are greatly deviated, and the printed image cannot be composed well, and the image quality is improved. There was a risk of damage.</p><p> The present invention has been made in view of such circumstances, and an object of the present invention is to suppress deterioration of image quality of a printed image even when the head is installed obliquely with respect to the moving direction. It is to plan.</p>

<p> The main inventions for achieving the above object are (A) a transport mechanism capable of carrying out a transport operation for transporting a medium with two or more different transport amounts, and (B) for the medium between the transport operations. It serves as a reference for ejecting the ink from the plurality of nozzles at the same timing from the plurality of nozzles that execute the moving ejection operation of ejecting the ink toward the medium while moving relative to each other. The signal output unit that outputs a signal, and (D) the amount of transport of the actually executed transport operation each time the transport operation is executed.<u style="single">And the inclination of the dots actually formed on the medium</u>A controller that changes the output timing of the signal from the signal output unit according to<u style="single">(E) The transfer operation is performed multiple times to print one image.</u>It is a printing apparatus characterized by this.</p><p> Other features of the present invention will be clarified by the description of the present specification and the accompanying drawings.</p>

=== Summary of Disclosure === The description of this specification and the accompanying drawings will clarify at least the following matters.

(A) A transport mechanism that can perform transport operations for transporting media with two or more different transport quantities, (B) A plurality of nozzles that perform a moving ejection operation of ejecting ink toward the medium while moving relative to the medium between the conveying operations. (C) A signal output unit that outputs a reference signal for ejecting the ink from the plurality of nozzles at the same timing. (D) A controller that changes the output timing of the signal from the signal output unit according to the amount of transport of the actually executed transport operation each time the transport operation is executed. A printing apparatus equipped with (E).

In such a printing apparatus, each time the transfer operation is executed, the output timing of the signal from the signal output unit can be changed according to the transfer amount of the actually executed transfer operation. The position of the dots formed by the ink ejected from the nozzle can be adjusted. As a result, even when the dots formed on the medium are formed at an oblique angle, the dot formation position can be adjusted each time the transfer operation is executed, so that the printed image can be printed. It is possible to prevent the quality of the product from being significantly impaired. Therefore, the image quality of the printed image can be improved.

In such a printing apparatus, the plurality of nozzles may be arranged along a predetermined direction. When a plurality of nozzles are arranged along a predetermined direction in this way, deterioration of the image quality of the printed image can be sufficiently suppressed.

Further, in such a printing apparatus, the direction in which the plurality of nozzles are arranged may intersect with the direction in which the medium is conveyed. When the direction in which the plurality of nozzles are arranged intersects with the direction in which the medium is conveyed, the dot formation position can be adjusted to improve the image quality of the printed image.

Further, in such a printing apparatus, the transfer amount of the transfer operation may differ depending on the printing method. Even if the transfer amount of the transfer operation differs depending on the printing method, the dot formation position can be adjusted and printed by changing the signal output timing according to the transfer amount of the transfer operation. It is possible to prevent deterioration of image quality.

Further, in such a printing apparatus, the transfer amount of the transfer operation may differ depending on the resolution of the image to be printed. Even if the amount of transport in the transport operation differs depending on the resolution of the image to be printed in this way, by changing the signal output timing, the dot formation position can be adjusted and the image quality of the printed image deteriorates. Can be prevented.

Further, in such a printing apparatus, even if the positions of dots formed on the medium by the inks ejected from the plurality of nozzles are gradually shifted along one direction each time the transfer operation is executed. good. In this way, the dot formation position gradually shifts along one direction each time the transfer operation is executed, so that deterioration of the image quality of the printed image can be prevented.

Further, in such a printing apparatus, the deviation width of the position of the dots formed on the medium by the inks ejected from the plurality of nozzles may differ depending on the transfer amount of the executed transfer operation. .. As described above, the deviation width of the dot formation position differs depending on the transport amount of the transport operation, so that the dots can be arranged at appropriate positions and the image quality of the printed image can be prevented from deteriorating.

Further, in such a printing apparatus, the controller may include a calculation unit for calculating the amount of change in the output timing. If such a calculation unit is provided, the amount of change in output timing can be easily calculated.

Further, in such a printing apparatus, the calculation unit may calculate the change amount of the output timing based on the transfer amount of the executed transfer operation and the predetermined correction information. If the calculation can be performed based on the transfer amount of the transfer operation and the predetermined correction information in this way, the change amount of the output timing can be easily calculated.

Further, in such a printing apparatus, the controller may include a table in which the transfer amount of the transfer operation to be executed and the change amount of the output timing are associated with each other. If such a table is provided, the amount of change in output timing can be easily obtained.

Further, in such a printing apparatus, a survey pattern for investigating an appropriate change amount of the output timing may be printed. By printing such a survey pattern, it is possible to easily survey the appropriate amount of change in output timing.

(A) A transport mechanism that can perform transport operations for transporting media with two or more different transport quantities, (B) A plurality of nozzles that perform a moving ejection operation of ejecting ink toward the medium while moving relative to the medium between the conveying operations. (C) A signal output unit that outputs a reference signal for ejecting the ink from the plurality of nozzles at the same timing. (D) A controller that changes the output timing of the signal from the signal output unit according to the transport amount of the transport operation each time the transport operation is executed. With (E) (F) The plurality of nozzles are arranged along a predetermined direction, (G) The direction in which the plurality of nozzles are arranged intersects with the direction in which the medium is conveyed. (H) The transport amount of the transport operation differs depending on the printing method or the resolution of the image to be printed. (I) The positions of the dots formed on the medium by the inks ejected from the plurality of nozzles are gradually shifted along one direction each time the transfer operation is executed. (J) The deviation width of the position of the dots formed on the medium by the inks ejected from the plurality of nozzles differs depending on the amount of the transferred operation executed. (K) The controller includes a calculation unit for calculating the amount of change in the output timing. (L) The calculation unit calculates the change amount of the output timing based on the transfer amount of the executed transfer operation and the predetermined correction information. (M) The controller includes a table in which the transfer amount of the transfer operation to be executed and the change amount of the output timing are associated with each other. (N) Print an investigation pattern for investigating the appropriate amount of change in the output timing. (O) A printing device characterized by that.

The transport operation of transporting the medium by the transport mechanism and It is a printing method that executes a moving ejection operation of ejecting ink from the nozzles toward the medium at the same timing while moving a plurality of nozzles relative to the medium between the conveying operations. hand, A printing method characterized in that each time the transfer operation is executed, the timing at which the ink is ejected from the plurality of nozzles is changed according to the transfer amount of the transfer operation actually executed.

A program that runs on a printing device The step of executing the transport operation of transporting the medium by the transport mechanism, and A step of executing a moving ejection operation of ejecting ink from the nozzles toward the medium while moving a plurality of nozzles relative to the medium between the conveying operations. Each time the transfer operation is executed, a signal that serves as a reference for ejecting the ink from the plurality of nozzles at the same timing is output from the signal output unit according to the transfer amount of the transfer operation actually executed. Steps to change the output timing and A program characterized by executing.

A printing system including a computer and a printing device capable of communicating with the computer. The printing device includes a transfer mechanism capable of performing a transfer operation for transporting a medium with two or more different transport amounts. A plurality of nozzles that perform a moving ejection operation of ejecting ink toward the medium while moving relative to the medium between the conveying operations. A signal output unit that outputs a reference signal for ejecting the ink from the plurality of nozzles at the same timing, and a signal output unit. It is characterized by including a controller that changes the output timing of the signal from the signal output unit according to the transfer amount of the transfer operation each time the transfer operation between the moving discharge operations is completed. Printing system.

=== Overview of printing equipment === An embodiment of the printing apparatus according to the present invention will be described by taking an inkjet printer as an example. 1 to 4 show the inkjet printer 1. FIG. 1 shows the appearance of the inkjet printer 1. FIG. 2 shows the internal configuration of the inkjet printer 1. FIG. 3 shows the configuration of the transport unit of the inkjet printer 1. FIG. 4 shows the system configuration of the inkjet printer 1.

As shown in FIG. 1, the inkjet printer 1 has a structure for ejecting a medium such as printing paper supplied from the back surface from the front surface, and an operation panel 2 and a paper ejection unit 3 are provided on the front surface portion thereof. , A paper feeding unit 4 is provided on the back surface thereof. The operation panel 2 is provided with various operation buttons 5 and indicator lamps 6. Further, the paper ejection unit 3 is provided with a paper ejection tray 7 that closes the paper ejection port when not in use. The paper feed unit 4 is provided with a paper feed tray 8 for holding a medium such as cut paper.

As shown in FIG. 2, a carriage 41 is provided inside the inkjet printer 1. The carriage 41 is provided so as to be relatively movable along the left-right direction. A carriage motor 42, a pulley 44, a timing belt 45, and a guide rail 46 are provided around the carriage 41. The carriage motor 42 is composed of a DC motor or the like, and is a drive source for relatively moving the carriage 41 in the left-right direction (hereinafter, also referred to as a carriage moving direction). The timing belt 45 is connected to the carriage motor 42 via a pulley 44, and a part of the timing belt 45 is connected to the carriage 41. The rotary drive of the carriage motor 42 causes the carriage 41 to move relative to the carriage moving direction (left-right direction). Move the carriage. The guide rail 46 guides the carriage 41 along the carriage moving direction (left-right direction).

In addition to this, around the carriage 41, a linear encoder 51 that detects the position of the carriage 41 and a direction in which the medium S intersects the moving direction of the carriage 41 (in the figure, the front-rear direction, hereinafter also referred to as the transport direction). A carriage roller 17A for transporting along the carriage 17A and a carriage motor 15 for rotationally driving the carriage 17A are provided.

On the other hand, the carriage 41 is provided with an ink cartridge 48 containing various inks and a head 21 for printing on the medium S. The ink cartridge 48 contains inks of various colors such as yellow (Y), magenta (M), cyan (C), and black (K), and can be attached to and detached from the cartridge mounting portion 49 provided on the carriage 41. It is attached to. Further, in the present embodiment, the head 21 ejects ink to the medium S to perform printing. For this purpose, the head 21 is provided with a large number of nozzles for ejecting ink.

In addition to this, inside the inkjet printer 1, printing is performed to prevent clogging of the nozzle of the head 21 and a pump device 31 that sucks ink from the nozzle to clear the clogging of the nozzle of the head 21. A capping device 35 or the like that seals the nozzle of the head 21 when it is not performed (standby, etc.) is provided.

Next, the transport unit of the inkjet printer 1 will be described. As shown in FIG. 3, the transport unit is provided with a paper feed roller 13, a paper detection sensor 53, a transport roller 17A, a paper discharge roller 17B, a platen 14, and free rollers 18A and 18B. There is.

The medium S to be printed is set in the paper feed tray 8. The medium S set in the paper feed tray 8 is conveyed along the direction of arrow A in the drawing by the paper feed roller 13 formed into a substantially D-shaped cross section, and is sent to the inside of the inkjet printer 1. The medium S sent to the inside of the inkjet printer 1 comes into contact with the paper detection sensor 53. The paper detection sensor 53 is installed between the paper feed roller 13 and the transfer roller 17A, and detects the medium S fed by the paper feed roller 13.

The medium S detected by the paper detection sensor 53 is sequentially conveyed to the platen 14 on which printing is performed by the transfer roller 17A. A free roller 18A is provided at a position facing the transport roller 17A. By sandwiching the medium S between the free roller 18A and the transport roller 17A, the medium S is smoothly transported.

The medium S fed to the platen 14 is sequentially printed by the ink ejected from the head 21. The platen 14 is provided so as to face the head 21 and supports the medium S to be printed from below.

The printed medium S is sequentially ejected to the outside of the printer by the paper ejection roller 17B. The paper ejection roller 17B is driven synchronously with the conveyor motor 15, sandwiches the medium S between the paper ejection roller 17B and the free roller 18B provided so as to face the paper ejection roller 17B, and ejects the medium S to the outside of the printer. To do.

&lt;System configuration&gt; Next, the system configuration of the inkjet printer 1 will be described. As shown in FIG. 4, the inkjet printer 1 includes a buffer memory 122, an image buffer 124, a controller 126, a main memory 127, a communication interface 129, a carriage motor control unit 128, a transfer control unit 130, and the like. It is provided with a head drive unit 132.

The communication interface 129 is a device in which the inkjet printer 1 exchanges data with an external computer 140 such as a personal computer. The communication interface 129 is connected to an external computer 140 by wire or wirelessly, and receives various data such as print data transmitted from the computer 140.

Various data such as print data received by the communication interface 129 are temporarily stored in the buffer memory 122. Further, the print data stored in the buffer memory is sequentially stored in the image buffer 124. The print data stored in the image buffer 124 is sequentially sent to the head drive unit 132. Further, the main memory 127 is composed of ROM, RAM, EEPROM and the like. Various programs and various setting data for controlling the inkjet printer 1 are stored in the main memory 127.

The controller 126 reads a control program and each setting data from the main memory 127, and controls the entire inkjet printer 1 according to the control program and various setting data. Further, detection signals from various sensors such as the rotary encoder 134, the linear encoder 51, and the paper detection sensor 53 are input to the controller 126.

When various data such as print data sent from the external computer 140 are received by the communication interface 129 and stored in the buffer memory 122, the controller 126 stores the necessary information from the stored data in the buffer memory. Read from 122. Based on the read information, the controller 126 refers to the output from the linear encoder 51 and the rotary encoder 134, and sets the carriage motor control unit 128, the transfer control unit 130, the head drive unit 132, and the like according to the control program. Control each.

The carriage motor control unit 128 drives and controls the rotation direction, rotation speed, torque, etc. of the carriage motor 42 in accordance with a command from the controller 126. The transfer control unit 130 controls the drive of the transfer motor 15 or the like that rotationally drives the transfer roller 17A in accordance with a command from the controller 126.

The head drive unit 132 drives and controls nozzles of each color provided in the head 21 based on the print data stored in the image buffer 124 in accordance with a command from the controller 126.

&lt;Head&gt; FIG. 5 is a diagram showing an arrangement of ink nozzles provided on the lower surface of the head 21. As shown in the figure, the lower surface of the head 21 has a plurality of nozzles # 1 to # 180 for each of the yellow (Y), magenta (M), cyan (C), and black (K) colors. Rows, namely cyan nozzle row 211C, magenta nozzle row 211M, yellow nozzle row 211Y, and black nozzle row 211K are provided.

The nozzles # 1 to # 180 of the nozzle rows 211C, 211M, 211Y, and 211K are linearly arranged along a predetermined direction. In the present embodiment, when the heads are normally installed, the nozzles # 1 to # 180 of the nozzle rows 211C, 211M, 211Y, and 211K are arranged along the transport direction of the medium S. It has become. The nozzle rows 211C, 211M, 211Y, and 211K are arranged in parallel at intervals along the moving direction (scanning direction) of the head 21. Each nozzle # 1 to # 180 is provided with a piezo element (not shown) as a driving element for ejecting ink droplets.

When a voltage having a predetermined time width is applied between the electrodes provided at both ends of the piezo element, the piezo element expands according to the voltage application time and deforms the side wall of the ink flow path. As a result, the volume of the ink flow path contracts according to the expansion and contraction of the piezo element, and the ink corresponding to this contraction becomes ink droplets and nozzles # 1 of the nozzle rows 211C, 211M, 211Y, and 211K of each color. It is discharged from ~ # 180.

=== Linear encoder === &lt;Encoder configuration&gt; FIG. 6 schematically shows the configuration of the linear encoder 51. The linear encoder 51 includes a linear encoder code plate 464 and a detection unit 466. As shown in FIG. 2, the linear encoder code plate 464 is attached to the frame side inside the inkjet printer 1. On the other hand, the detection unit 466 is attached to the carriage 41 side. When the carriage 41 moves along the guide rail 46, the detection unit 466 moves relatively along the linear encoder code plate 464. As a result, the detection unit 466 detects the amount of movement of the carriage 41.

&lt;Configuration of detector&gt; FIG. 7 schematically shows the configuration of the detection unit 466. The detection unit 466 includes a light emitting diode 452, a collimator lens 454, and a detection processing unit 456. The detection processing unit 456 includes a plurality of (for example, four) photodiodes 458, a signal processing circuit 460, and, for example, two comparators 462A and 462B.

When a voltage Vcc is applied to both ends of the light emitting diode 452 via a resistor, light is emitted from the light emitting diode 452. This light is condensed into parallel light by the collimator lens 454 and passes through the linear encoder code plate 464. The linear encoder code plate 464 is provided with slits at predetermined intervals (for example, 1/180 inch (1 inch = 2.54 cm)).

The parallel light that has passed through the linear encoder code plate 464 enters each photodiode 458 through a fixed slit (not shown) and is converted into an electric signal. The electric signals output from the four photodiodes 458 are signal processed by the signal processing circuit 460, the signals output from the signal processing circuit 460 are compared by the comparators 462A and 462B, and the comparison result is output as a pulse. The pulses ENC-A and ENC-B output from the comparators 462A and 462B are the outputs of the linear encoder 51.

&lt;Output signal&gt; 8A and 8B are timing charts showing waveforms of two output signals of the detection unit 466 during forward rotation and reverse rotation of the carriage motor 42. As shown in FIGS. 8A and 8B, the phases of the pulse ENC-A and the pulse ENC-B are different by 90 degrees in both the forward rotation and the reverse rotation of the carriage motor 42. When the carriage motor 42 is rotating forward, that is, when the carriage 41 is moving along the guide rail 46, the pulse ENC-A is only 90 degrees more than the pulse ENC-B, as shown in FIG. 8A. When the phase is advanced and the carriage motor 42 is reversed, the pulse ENC-A is 90 degrees behind the pulse ENC-B, as shown in FIG. 8B. Then, one cycle T of the pulse ENC-A and the pulse ENC-B is equal to the time for the carriage 41 to move the slit interval of the linear encoder code plate 464.

Then, the rising edges of the output pulses ENC-A and ENC-B of the linear encoder 51 are detected, the number of detected edges is counted, and the rotation position of the carriage motor 42 is calculated based on this counted value. To. This count adds "+1" when one edge is detected when the carriage motor 42 is rotating forward, and "-1" when one edge is detected when the carriage motor 42 is rotating in the reverse direction. "Is added. Each period of the pulses ENC-A and ENC-B is equal to the time from when one slit passes through the detection unit 466 to when the next slit passes through the detection unit 466 of the linear encoder code plate 464, and , Pulse ENC-A and pulse ENC-B are 90 degrees out of phase. Therefore, the count value "1" of the above count corresponds to 1/4 of the slit spacing of the linear encoder code plate 464. As a result, if the count value is multiplied by 1/4 of the slit interval, the amount of movement of the carriage motor 42 from the rotation position corresponding to the count value "0" can be obtained based on the multiplication value. At this time, the resolution of the linear encoder 51 is 1/4 of the slit spacing of the linear encoder code plate 464.

=== Rotary encoder === The configuration of the rotary encoder will be described. FIG. 9 is an explanatory diagram illustrating the configuration of the rotary encoder 134. The rotary encoder 134 includes a rotary encoder code plate 402 and a detection unit 404 provided adjacent to the rotary encoder code plate 402. As shown in the figure, the rotary encoder code plate 402 is formed in a disk shape. A large number of small slits 406 are formed at predetermined intervals on the outer peripheral edge of the rotary encoder code plate 402. The rotary encoder code plate 402 is integrally provided adjacent to the large gear 408 integrally provided at the shaft end of the transfer roller 17A that conveys the medium S. The large gear 408 is connected to the paper transport motor 15 via the small gear 410, and is rotated via the small gear 410 by the rotational drive of the paper transport motor 15. As a result, the transfer roller 17A is rotated by the rotational drive of the paper transfer motor 15, and the rotary encoder code plate 402 is also rotated in synchronization with the large gear 408 and the transfer roller 17A. The detection unit 404 of the rotary encoder 134 has substantially the same configuration as the detection unit 466 of the linear encoder 51.

=== Head drive circuit === FIG. 10 shows an example of the drive circuit 220 of the head 21. Further, FIG. 11 is a timing chart illustrating each signal of the drive circuit 220.

The drive circuit 220 is provided for ejecting ink from nozzles # 1 to # 180 provided on the head 21, and 180 pieces are provided corresponding to each nozzle # 1 to # 180. Drives the piezo elements PZT (1) to (180). The piezo elements PZT (1) to (180) are driven based on the print signal PRTS input to the drive circuit 220. In the figure, the numbers in parentheses at the end of each signal or component indicate the nozzle numbers 1 to 180 to which the signal or component corresponds.

In the present embodiment, such a drive circuit 220 is individually provided for each nozzle row 211Y, 211M, 211C, and 211K provided on the head 21. That is, four nozzle drive circuits 220 are provided corresponding to the yellow nozzle row 211Y, the magenta nozzle row 211M, the cyan nozzle row 211C, and the black nozzle row 211K, respectively.

The configuration of the drive circuit 220 will be described. As shown in FIG. 10, the drive circuit 220 includes an original drive signal generator 222 that generates an original drive signal ODRV, 180 first shift registers 224 (1) to (180), and 180 second shifts. It includes registers 226 (1) to (180), a latch circuit group 228, a data selector 230, and 180 switches SW (1) to (180).

The prime drive signal generation unit 222 generates the prime drive signal ODRV that is commonly used for the nozzles # 1 to # 180. This original drive signal ODRV is a signal for driving the respective piezo elements PZT (1) to (180) provided corresponding to the respective nozzles # 1 to # 180. As shown in FIG. 11, this original drive signal ODRV has a plurality of pulses within the main scanning period of one pixel (within the time when the carriage 41 crosses the interval of one pixel), in this case, the first pulse W1 and the second pulse. It is a signal having a pulse W2. In the original drive signal ODRV, these plurality of pulses (first pulse W1 and second pulse W2) are repeatedly generated at a predetermined cycle. The original drive signal ODRV generated by the original drive signal generation unit 222 is output to each switch SW (1) to (180).

On the other hand, the print signal PRTS (see FIG. 10) is a data signal including 180 2-bit data for driving the respective piezo elements (1) to (180), and the ink from each nozzle # 1 to # 180. It is a signal instructing whether or not the ink is ejected and the size of the ink to be ejected. Such a print signal PRTS is serially transmitted to the drive circuit 220 and input to 180 first shift registers 224 (1) to (180). Next, the print signal PRTS is input to the second shift registers 226 (1) to (180). Here, the first bit data of the 180 2-bit data is input to the first shift registers 224 (1) to (180), respectively. Further, the second bit data of the 180 2-bit data is input to the second shift registers 226 (1) to (180), respectively.

The latch circuit group 228 latches the data stored in the first shift registers 224 (1) to (180) and the second shift registers 226 (1) to (180) to be "0 (Low)" or "1". (High) signal is taken out. Then, the latch circuit group 228 sends the signals extracted based on the data stored in the first shift registers 224 (1) to (180) and the second shift registers 226 (1) to (180) to the data selector 230, respectively. Is output. The latch timing of the latch circuit group 228 is controlled by the latch signal (LAT) input to the latch circuit group 228. That is, when a pulse as shown in FIG. 11 is input to the latch circuit group 228 as a latch signal (LAT), the latch circuit group 228 has the first shift registers 224 (1) to (180) and the first shift register group 228. 2 Latch the data stored in shift registers 226 (1) to (180). The latch circuit group 228 latches each time a pulse is input as a latch signal (LAT).

On the other hand, the data selector 230 uses the first shift registers 224 (1) to (180) and the second shift registers 224 (1) to (180) from the signals output from the latch circuit group 228 (0 (Low) or 1 (High) signals). Select the signal corresponding to any one of the shift registers 226 (1) to (180) and output it to the switches SW (1) to (180) as print signals PRT (1) to (180). .. The switching of the signal selected by the data selector 230 is performed by both the latch signal (LAT signal) and the change signal (CH signal) input to the data selector 230.

Here, when a pulse as shown in FIG. 11 is input to the data selector 230 as a latch signal (LAT signal), the data selector 230 uses the data stored in the second shift registers 226 (1) to (180). Select the signal corresponding to, and output it to the switches SW (1) to (180) as print signals PRT (1) to (180). When a pulse as shown in FIG. 11 is input to the data selector 230 as a change signal (CH signal), the data selector 230 shifts to the data stored in the second shift registers 226 (1) to (180). The selected signal is switched from the corresponding signal to the signal corresponding to the data stored in the first shift registers 224 (1) to (180), and the switch SW is used as the print signal PRT (1) to (180). Output to (1) to (180). Then, when a pulse is input again as a latch signal (LAT signal), the data selector 230 uses the second shift register from the signals corresponding to the data stored in the first shift registers 224 (1) to (180). The selected signal is switched to the signal corresponding to the data stored in 226 (1) to (180), and output to the switches SW (1) to (180) as print signals PRT (1) to (180). To do.

Here, as shown in FIG. 11, a pulse is generated in the latch signal (LAT signal) at a cycle of one pixel unit. Further, as shown in FIG. 11, a pulse is generated in the change signal (CH signal) at the timing exactly in the middle of the cycle for one pixel. From this, 2-bit data corresponding to one pixel is serially transmitted to the switches SW (1) to (180), respectively. That is, 2-bit data such as "00", "01", "10", and "11" are used as print signals PRT (1) to (180) for each pixel cycle, and switches SW (1) to (1) to ( It is entered in 180) respectively.

The switches SW (1) to (180) are the print signals PRT (1) to (180) output from the data selector 230, that is, 2-bit data such as "00", "01", "10", and "11". Based on, it is determined whether or not to pass the original drive signal ODRV input from the original drive signal generation unit. That is, when the level of the print signal PRT (i) is "1 (High)", the drive signal DRV (i) is passed through the corresponding drive pulse (first pulse W1 or second pulse W2) of the original drive signal ODRV as it is. ). On the other hand, when the level of the print signal PRT (i) is "0 (Low)", the switches SW (1) to (180) are set to the corresponding drive pulse (first pulse W1 or second pulse W2) of the original drive signal ODRV. ) Is blocked.

Therefore, the drive signal DRV (i) input from the switches SW (1) to (180) to the piezo elements PZT (1) to (180) is the switch SW (1) from the data selector 230 as shown in FIG. It differs depending on the print signals PRT (1) to (180) input for) to (180), that is, 2-bit data such as "00", "01", "10", and "11".

Here, when "10" is input to the switch SW (i) as the print signal PRT (i), only the first pulse W1 passes through the switch SW (i) and is input to the piezo element PZT (i). Will be done. The piezo element PZT (i) is driven by the first pulse W1, and small-sized ink droplets (hereinafter, also referred to as small ink droplets) are ejected from the nozzle. As a result, small-sized dots (medium dots) are formed on the medium S.

When "01" is input to the switch SW (i) as the print signal PRT (i), only the second pulse W2 passes through the switch SW (i) and is input to the piezo element PZT (i). To. The piezo element PZT (i) is driven by this second pulse W2, and ink droplets having a size larger than the smaller ink droplets (hereinafter, also referred to as medium ink droplets) are ejected from the nozzle. To. As a result, medium-sized dots (medium dots) are formed on the medium S.

When "11" is input to the switch SW (i) as the print signal PRT (i), both the first pulse W1 and the second pulse W2 pass through the switch SW (i) and the piezo element PZT. Entered in (i). The piezo element PZT (i) is driven by these first pulse W1 and second pulse W2, and small ink droplets and medium ink droplets are ejected from the nozzle. Here, the small ink droplet and the medium ink droplet are continuously ejected with a predetermined time difference. As a result, the medium S is formed with small dots formed by the small ink droplets and medium dots formed by the medium ink droplets. These small dots and medium dots form pseudo-large size dots (large dots) on the medium S.

When "00" is input to the switch SW (i) as the print signal PRT (i), neither the first pulse W1 nor the second pulse W2 passes through the switch SW (i), and the piezo element No drive pulse is input to PZT (i). As a result, ink droplets are not ejected from the nozzles, and dots are not formed on the medium S.

&lt;PTS signal&gt; Both the latch signal (LAT signal) and the change signal (CH signal) input to the latch circuit group 228 or the data selector 230 are generated based on the PTS (Pulse Timing Signal) signal. The PTS signal is a signal that defines the timing at which a pulse is generated in the latch signal (LAT signal) and the change signal (CH signal). The pulse of the PTS signal is generated based on the output pulses ENC-A and ENC-B from the linear encoder 51 (detection unit 466). That is, the pulse of the PTS signal is generated according to the amount of movement of the carriage 41. This PTS signal corresponds to "a reference signal for ejecting ink from a plurality of nozzles at the same timing".

FIG. 12 details the timing relationship between the PTS signal, the latch signal (LAT signal), and the change signal (CH signal). A pulse is generated in the PTS signal at a predetermined period T0. A pulse is generated for each of the latch signal (LAT signal) and the change signal (CH signal) based on the pulse generated in this PTS signal. The pulse of the latch signal (LAT signal) is generated immediately after the pulse is generated by the PTS signal. On the other hand, as for the change signal (CH signal), the pulse is generated after a predetermined time elapses after the pulse is generated by the PTS signal. Each pulse of the latch signal (LAT signal) and the change signal (CH signal) is generated each time a pulse is generated in the PTS signal.

The PTS signal is generated by the controller 126. The controller 126 generates a PTS signal pulse based on the output pulses ENC-A and ENC-B from the linear encoder 51 (detection unit 466), and also generates a pulse based on the print data sent from the computer 140. Change the timing and cycle as appropriate. The PTS signal generated by the controller 126 is output to the head drive unit 132. The head drive unit 132 generates a latch signal (LAT signal) and a change signal (CH signal) based on the PTS signal from the controller 126, and the original drive signal generation unit 222 generates the original drive signal ODRV.

Here, the controller 126 that generates a PTS signal and outputs it to the head drive unit 132 corresponds to a signal output unit.

=== Printing operation === Next, the printing operation of the inkjet printer 1 described above will be described. Here, "two-way printing" will be described as an example. FIG. 13 is a flowchart showing an example of the processing procedure of the printing operation of the inkjet printer 1. Each process described below is executed by the controller 126 reading a program from the main memory 127 and controlling the carriage motor control unit 128, the transport control unit 130, the head drive unit 132, and the like according to the program. The program.

When the controller 126 receives the print data from the computer 140, the controller 126 first performs a paper feed process in order to execute printing based on the print data (S102). The paper feed process is a process of supplying the medium S to be printed into the inkjet printer 1 and transporting the medium S to the print start position (also referred to as the cue position). The controller 126 rotates the paper feed roller 13 to send the medium S to be printed to the transport roller 17A. The controller 126 rotates the transport roller 17A to position the medium S sent from the paper feed roller 13 at the printing start position (near above the platen 14).

Next, the controller 126 drives the carriage motor 42 through the carriage motor control unit 128 to move the carriage 41 relative to the medium S and execute a printing process for printing on the medium S. Here, first, while moving the carriage 41 along the guide rail 46 in one direction, outbound printing in which ink is ejected from the head 21 is executed (S104). The controller 126 drives the carriage motor 42 to move the carriage 41, and drives the head 21 based on the print data to eject ink (corresponding to "moving ejection operation"). The ink ejected from the head 21 reaches the medium S and is formed as dots.

After printing in this way, the controller 126 then executes a transport process for transporting the medium S by a predetermined amount (S106). This transport process corresponds to a "transport operation". Here, the controller 126 drives the transfer motor 15 through the transfer control unit 130 to rotate the transfer roller 17A, and transfers the medium S by a predetermined amount in the transfer direction relative to the head 21. By this transfer process, the head 21 can print in an area different from the area printed earlier.

After performing the transfer process in this way, the controller 126 executes a paper ejection determination as to whether or not the paper should be ejected (S108). Here, the controller 126 executes the paper ejection process if there is no other data to be printed on the medium S being printed (S116). On the other hand, if there is other data to be printed on the medium S being printed, the controller 126 executes return printing without performing the paper ejection process (S110). In this return printing, the carriage 41 is moved along the guide rail 46 in the direction opposite to the outward printing, and printing is performed. Here, too, the controller 126 rotates and drives the carriage motor 42 through the carriage motor control unit 128 to move the carriage 41, and drives the head 21 based on the print data to eject ink for printing. To give.

After executing the return printing, the transport process is executed (S112), and then the paper ejection judgment is performed (S114). Here, if there is other data to be printed on the medium S being printed, the process returns to step S104 and the outbound printing is executed again without performing the paper ejection process (S104). On the other hand, if there is no other data to be printed on the medium S being printed, the paper ejection process is executed (S116).

After the paper ejection process is performed, the print end determination for determining whether or not the print is completed is executed (S118). Here, the computer 140 then checks whether there is a medium S to be printed next based on the print data. Here, if there is a medium S to be printed next, the process returns to step S102, the paper feed process is executed again, and printing is started. On the other hand, if there is no medium S to be printed next, the printing process is terminated.

=== Printing method === &lt;Interlaced method&gt; FIG. 14 schematically describes a method of printing an image G by forming dots on the medium S by an interlace method. Here, for convenience of explanation, the nozzle row 211 for ejecting ink is drawn as if it is moving with respect to the medium S, but the figure shows the relative positional relationship between the nozzle row 211 and the medium S. In reality, the medium S is moving along the transport direction. Further, in the figure, the nozzles indicated by black circles are nozzles that eject ink, and the nozzles indicated by white circles are nozzles that do not eject ink. FIG. 14A shows the position of the nozzle row 211 (head 21) in paths 1 to 4, and the state of dot formation, and FIG. 14B shows the position and dot of the nozzle row 211 (head 21) in paths 1 to 6. It shows the state of formation of.

Here, the pass refers to an operation in which the head 21 having the nozzle row 211 moves once along the moving direction of the carriage 41 due to the movement of the carriage 41. In the "interlace method", by repeatedly executing such "passes", dots are arranged and formed along the moving direction of the carriage 41 for each pass, and raster lines constituting the image G to be printed are sequentially formed. Then print the image G. The "raster line" is a row of pixels arranged in the moving direction of the carriage 41, and is also called a scanning line. Further, the "pixel" is a grid-shaped grid virtually defined on the medium S in order to define a position where ink droplets are landed and dots are recorded.

In the interlace method, each time the medium S is conveyed in the transfer direction with a constant transfer amount F, each nozzle records the raster line immediately above the raster line recorded in the path immediately before the medium S. In order to record with a constant transfer amount in this way, the number of nozzles N (integer) capable of ejecting ink is relatively prime to k, and the transfer amount F is set to N and D.

Here, it is shown that the image G is formed by using # 1 to # 4 of the nozzles # 1 to # 180 in the nozzle row 211. Since the nozzle pitch of the nozzle row 211 is 4D, not all nozzles can be used in order to satisfy the condition "N and k are relatively prime" for the interlaced method. Therefore, here, a case where the image G is formed by the interlace method using three nozzles # 1 to # 3 will be briefly described. Further, since three nozzles are used, the medium S is conveyed with a transfer amount of 3 D. As a result, for example, using the nozzle row 211 with a nozzle pitch of 180 dpi (4 · D), dots are formed on the paper at a dot interval of 720 dpi (= D).

In the figure, the first raster line is formed by the nozzle # 1 of the path 3, the second raster line is formed by the nozzle # 2 of the path 2, and the third raster line is formed by the nozzle # 3 of the path 1. , The fourth raster line shows how nozzle # 1 of pass 4 is formed to form a continuous raster line. In pass 1, only nozzle # 3 ejects ink, and in pass 2, only nozzle # 2 and nozzle # 3 eject ink. This is because if ink is ejected from all the nozzles in pass 1 and pass 2, a continuous raster line cannot be formed on the medium S. In pass 3 and later, three nozzles (# 1 to # 3) eject ink, the paper is conveyed with a constant transfer amount F (= 3 · D), and continuous raster lines are dot-spaced. Formed at D. As a result, raster lines are sequentially formed for each pass, and the image G is printed.

FIG. 15 illustrates another method of the interlaced method. Here, the number of nozzles used is different. Since the nozzle pitch and the like are the same as in the above-described explanatory drawing, the description thereof will be omitted. FIG. 15A shows the position of the nozzle row 211 and the formation of dots in paths 1 to 4, and FIG. 15B shows the position of the nozzle row 211 and the formation of dots in paths 1 to 9.

In the figure, an example of printing the image G on the medium S by using # 1 to # 8 of the nozzles # 1 to # 180 of the nozzle row 211 will be described. Here, since the nozzle pitch of the nozzle row 211 is 4D, not all nozzles can be used in order to satisfy the condition "N and k are relatively prime" for performing in the interlaced method. Therefore, here, a case where the interlacing method is performed using seven nozzles # 1 to # 7 will be briefly described. The transport amount of the medium S is set to "7 D" because seven nozzles # 1 to # 7 are used.

In the figure, the first raster line is formed by the nozzle # 2 of the path 3, the second raster line is formed by the nozzle # 4 of the path 2, and the third raster line is formed by the nozzle # 6 of the path 1. , The fourth raster line shows how nozzle # 1 of pass 4 is formed to form a continuous raster line. In pass 3 and later, seven nozzles (# 1 to # 7) eject ink, the medium S is conveyed with a constant transfer amount F (= 7 · D), and continuous raster lines are dots. Formed at intervals D.

Compared with the above-mentioned interlace method, the number of nozzles used for ejecting ink is large. Therefore, since the number of nozzles N for ejecting ink is large, the amount of ink conveyed at one time is large, and the printing speed is increased. As described above, when the interlaced method is performed, if the number of nozzles capable of ejecting ink increases, the printing speed becomes high, which is advantageous.

&lt;Overlap method&gt; FIG. 16 schematically illustrates a method of printing the image G on the medium S by the overlap method. FIG. 16A shows the position of the nozzle row 211 and the formation of dots in paths 1 to 8, and FIG. 16B shows the position of the nozzle row 211 and the formation of dots in paths 1 to 12. In the above-mentioned interlace method, one raster line is formed by one nozzle. On the other hand, in the overlap method, for example, one raster line is formed by two or more nozzles.

In the overlap method, each nozzle intermittently forms dots every few dots each time the medium S is transported in the transport direction with a constant transport amount F. Then, in another path, one raster line is completed by the plurality of nozzles by forming the dots so as to complement the intermittent dots already formed by the other nozzles. When one raster line is completed in M passes in this way, it is defined as the number of overlaps M. In the figure, since each nozzle intermittently forms dots every other dot, dots are formed in odd-numbered pixels or even-numbered pixels for each pass. Since one raster line is formed by two nozzles, the number of overlaps is M = 2. In the case of the above-mentioned interlace method, the number of overlaps is M = 1.

In the overlap method, the following conditions (1) to (3) are required in order to record with a constant transport amount. (1) N / M is an integer. (2) N / M is relatively prime to k. (3) The transport amount F is set to (N / M) · D.

In the figure, the number of nozzles in the nozzle row 211 is 180. However, since the nozzle pitch of the nozzle row 211 is 4D (k = 4), all nozzles are required to satisfy the condition for printing by the overlap method, "N / M and k are relatively prime". Cannot be used. Therefore, here, an example in which the image G is printed using # 1 to # 6 of the nozzles # 1 to # 180 of the nozzle row 211 will be briefly described. Since six nozzles are used, the medium S is conveyed with a transfer amount of 3 D. As a result, for example, using a nozzle array with a nozzle pitch of 180 dpi (4 · D), dots are formed on the medium S at a dot interval of 720 dpi (= D). Also, in one pass, each nozzle intermittently forms dots every other dot in the scanning direction. In the figure, the raster line in which two dots are drawn in the direction of carriage movement has already been completed. For example, in FIG. 16A, the first raster line to the sixth raster line have already been completed. A raster line on which one dot is drawn is a raster line in which dots are formed intermittently every other dot. For example, in the 7th and 10th raster lines, dots are formed intermittently every other dot. The seventh raster line, in which dots are intermittently formed every other dot, is completed by forming dots so that nozzle # 1 in pass 9 complements them.

In the figure, the first raster line is formed by nozzle # 4 of pass 3 and nozzle # 1 of pass 7, and the second raster line is formed by nozzle # 5 of pass 2 and nozzle # 2 of pass 6. The fourth raster line is formed by nozzle # 6 of pass 1 and nozzle # 3 of pass 5, and the fourth raster line is formed by nozzle # 4 of pass 4 and nozzle # 1 of pass 8, and is a continuous raster line. Is shown to be formed. In passes 1 to 6, there are nozzles # 1 to nozzles # 6 that do not eject ink. This is because if ink is ejected from all the nozzles in passes 1 to 6, a continuous raster line cannot be formed on the medium S. In pass 7 and later, six nozzles (# 1 to # 6) eject ink, the medium S is conveyed with a constant transfer amount F (= 3 · D), and continuous raster lines are dots. Formed at intervals D.

The formation positions of the dots formed in each path in the scanning direction are summarized below. <img file="JP4591013B2_D0001.tif" />

Here, "odd number" means that a dot is formed in the odd-numbered pixel among the pixels (raster line pixel) arranged in the carriage moving direction. Further, "even number" in the table means that dots are formed in the even numbered pixels among the pixels arranged in the scanning direction. For example, in pass 3, each nozzle forms a dot in the odd-numbered pixels. When one raster line is formed by M nozzles, k × M passes are required to complete the raster lines for the nozzle pitch. For example, in the present embodiment, since one raster line is formed by two nozzles, eight passes (4 × 2) are required to complete the four raster lines. As can be seen from Table 1, dots are formed in the order of odd-even-odd-even in the first four passes. As a result, when the first four passes are completed, dots are formed in the even-numbered pixels on the raster line next to the raster line in which the dots are formed in the odd-numbered pixels. In the latter four passes, dots are formed in the order of even-odd-even-odd. That is, in the latter four passes, dots are formed in the reverse order of the first half four passes. As a result, dots are formed so as to complement the gaps between the dots formed by the first half pass.

Similar to the above-mentioned interlace method, the overlap method also increases the number of nozzles N capable of ejecting ink, the larger the amount of ink conveyed at one time, and the faster the printing speed. Therefore, if the number of nozzles capable of ejecting ink increases when the overlap method is used, the printing speed becomes faster, which is advantageous.

&lt;Other printing methods&gt; Other printing methods other than the interlace method and the overlap method include a band printing method and a draft printing method.

=== Conventional problems === In such an inkjet printer 1, the head 21 may be installed at an angle with respect to the moving direction of the carriage 41 (corresponding to the moving direction of the nozzle). The main reasons why the head 21 is installed at an angle in this way are as follows. (A) The head 21 is fixed in a tilted state within the manufacturing error range. (B) When the head 21 is detachably provided, the head 21 is tilted and attached when the head 21 is attached again after the head 21 is removed for maintenance or the like.

FIG. 17 shows an example when the head 21 is installed at an angle. Here, as shown in the figure, the head 21 is installed at an angle to the left. When the head 21 is installed obliquely with respect to the moving direction of the carriage 41 in this way, the nozzle rows 211C, 211M, 211Y, and 211K provided on the head 21 are orthogonal to the moving direction of the carriage 41, respectively. It is not placed and is placed at an angle. As a result, the nozzle rows 211C, 211M, 211Y, and 211K are not arranged parallel to the conveying direction of the medium S, but are arranged obliquely with respect to the conveying direction of the medium S. As a result, the arrangement of the nozzles # 1 to # 180 becomes oblique with respect to the transport direction of the medium S, and when ink is ejected from the nozzles # 1 to # 180, dots are formed diagonally. There has occurred.

FIG. 18 illustrates an example of the dot formation state when the head 21 is installed obliquely with respect to its moving direction. Here, a case where the nozzle row 211 has eight nozzles # 1 to # 8 will be briefly described as an example. Further, the operation in which the nozzle row 211 moves along the moving direction due to the movement of the carriage 41, that is, the case where the so-called "pass" is performed four times will be described here. The positions of the dots formed in the first pass (path 1) are indicated by circles numbered 1. The positions of the dots formed in the second pass (pass 2) are indicated by circles numbered 2. The positions of the dots formed in the third pass (pass 3) are indicated by circles numbered 3. The positions of the dots formed in the fourth pass (pass 4) are indicated by circles numbered 4.

As shown in the figure, when the nozzle row 211 is arranged diagonally with respect to the transport direction of the medium S, when the nozzle row 211 moves due to the movement of the carriage 41, ink is ink from each of the nozzles # 1 to # 8. When is ejected, the dots formed by the ejected ink are formed diagonally parallel to the arrangement direction of the nozzles # 1 to # 8 (see the circles numbered "1" in the figure). .. Ink is ejected from the nozzles # 1 to # 8 at the same timing.

Further, when the movement of the carriage 41 is completed (the end of "pass 1") and the next path ("path 2") is executed, the medium S is conveyed by a predetermined amount along the conveying direction. As a result, the medium S is moved upward relative to the nozzle row 211 as shown in the figure. Here, when the carriage 41 starts moving again, the nozzle row 211 moves along the moving direction of the carriage 41 while being inclined at an angle. Therefore, the dots formed by the inks ejected from the nozzles # 1 to # 8 are formed diagonally along the arrangement direction of the nozzles # 1 to # 8, as in the case of "pass 1". To. The positions of the dots formed here are indicated by circles numbered "2". In this way, when the dots (circles numbered "2") are formed diagonally in "Pass 2", the dots formed in "Pass 2" (numbered "2") are attached. The circle mark) is formed at a position relatively largely deviated from the dot formed by the pass 1 (the circle mark numbered 1).

Further, when the "pass 2" ends and the next pass, that is, the "pass 3" is executed, the medium S moves relatively upward with respect to the nozzle row 211, and the carriage 41 moves to the medium. When the dots are moved relative to S, the dots formed by the inks ejected from the nozzles # 1 to # 8 are the nozzles # as indicated by the circles numbered "3" in the figure. It is formed diagonally along the arrangement direction of 1 to # 8. In this way, when the dots (circles numbered "3") are formed diagonally in "pass 3", the dots formed in "pass 3" (numbered "3") are attached. The circle mark) is formed at a position relatively largely deviated from the dot formed by the pass 2 (the circle mark numbered 2).

Then, when the medium S further moves upward relative to the nozzle array 211 and "pass 4" is executed, the dots formed by the inks ejected from the nozzles # 1 to # 8 are displayed. As shown in the figure (circles marked with "4"), the nozzles # 1 to # 8 are formed diagonally along the arrangement direction. In this way, when the dots (circles numbered "4") are formed diagonally in "pass 4", the dots formed in "pass 3" (numbered "4") are attached. The circles) will be formed at positions that are relatively large deviations from the dots formed by the "pass 3" (circles numbered "3").

When "pass 1" to "pass 4" are executed with the nozzle rows arranged diagonally with respect to the transport direction of the medium S in this way, each "pass 1" to "pass 4" is set. The dots (circles numbered "1" to "4") formed by the ink ejected from the nozzles # 1 to # 8 are formed at positions that are offset from each other. In some cases, the pixels constituting the image to be printed could not be properly formed. For this reason, the composition of the printed image may be greatly disturbed, which may greatly affect the image quality of the printed image.

FIG. 19 shows a dot formation state when the head 21 is properly installed without being tilted diagonally with respect to the moving direction of the carriage 41. When the head 21 is not tilted with respect to the moving direction of the carriage 41, the nozzle row 211 is arranged parallel to the transport direction of the medium S as shown in the figure. Therefore, the nozzles # 1 to # 180 in the nozzle row 211 are also arranged in parallel with the transport direction of the medium S. As a result, when the nozzle row moves along the moving direction of the carriage due to the movement of the carriage 41, ink is ejected from each of the nozzles # 1 to # 8, and when "pass 1" is executed, the ink is ejected. The dots formed by the ink are formed side by side along the transport direction of the medium S, as indicated by the circles numbered 1 in the figure. Similarly, when "pass 2" to "pass 4" are executed, the dots formed by the ink ejected from the nozzles # 1 to # 8 are shown in the figure of "pass 2" to "pass 4". As shown by the circles numbered "2" to "4" for each "pass 4", they are formed side by side along the transport direction of the medium S.

If the head 21 is properly installed without being tilted diagonally with respect to the moving direction of the carriage 41 in this way, the dots formed in each of "pass 1" to "pass 4" are as shown in the figure. It is not formed in a misaligned position, but is formed in a properly arranged state. As a result, the pixels constituting the image to be printed can be properly formed, and a high-quality printed image can be obtained.

=== Solution === In the inkjet printer 1 according to the present embodiment, even when the head 21 is installed at an angle with respect to the moving direction of the carriage 41 in this way, it is possible to prevent the dot arrangement from being disturbed. , It is possible to suppress deterioration of the image quality of the printed image. The method will be described in detail below.

FIG. 20 illustrates a dot formation state when the head 21 is installed obliquely with respect to the moving direction of the carriage 41 in the inkjet printer 1 according to the present embodiment. Here, a case where the nozzle row 211 has eight nozzles # 1 to # 8 will be briefly described as an example. Further, the operation in which the nozzle row 211 moves along the moving direction due to the movement of the carriage 41, that is, the situation when the so-called "pass" is performed four times is schematically shown here. The positions of the dots formed in the first pass ("path 1") are simply indicated by circles numbered "1", and the dots formed in the second pass ("path 2"). The position of is simply indicated by a circle numbered "2", and the position of the dot formed in the third pass ("Path 3") is simply numbered "3". It is indicated by a circle, and the position of the dot formed in the fourth pass (path 4) is simply indicated by a circle numbered 4.

In the inkjet printer 1 according to the present embodiment, when the head 21 is installed obliquely with respect to the moving direction, the nozzle row 211 is not parallel to the conveying direction of the medium S as shown in the figure. Arranged diagonally without. When the nozzle row 211 moves along the moving direction of the carriage 41 due to the movement of the carriage 41, ink is ejected from the nozzles # 1 to # 8 of the nozzle row 211 at the same timing, so that each nozzle # As shown in the figure, the dots formed by the inks ejected from 1 to # 8 are arranged diagonally along the arrangement direction of the nozzles # 1 to # 8.

Here, when the movement of the carriage 41 is completed (the end of "path 1") and the next path ("path 2") is executed, the medium S is conveyed by a predetermined amount along the conveying direction. .. As a result, the medium S is moved upward relative to the nozzle row 211 as shown in the figure.

When the movement of the carriage 41 is started and ink is ejected again from the nozzles # 1 to # 8 to execute "pass 2", the nozzle row 211 is tilted diagonally along the moving direction of the carriage 41. And move. When the nozzle row 211 moves along the moving direction of the carriage 41 in this way, ink is ejected from the nozzles # 1 to # 8 of the nozzle row 211 at the same timing, and ink is ejected onto the medium. , Dots are formed diagonally by the ink ejected from each of the nozzles # 1 to # 8.

In the present embodiment, the timing of ejecting ink from the nozzles # 1 to # 8 is changed here. This timing change is the position of the dots formed by the ink ejected from each nozzle # 1 to # 8 in the previous pass, that is, "pass 1" (the position of the circle marked with "1"). It is done in response to. That is, as shown in the figure, the positions of the dots formed by the inks ejected from the nozzles # 1 to # 8 (the positions of the circles numbered "2") are the previous paths, that is, the positions of the circles. The timing at which ink is ejected from each nozzle # 1 to # 8 is changed so as to be aligned with the position of the dots (circles numbered "1") formed in "pass 1". As a result, the positions of the dots formed by "pass 1" (circles numbered "1") and the dots formed by "path 2" (circles numbered "2") The position of) does not have to be separated as in the past.

Furthermore, even when "path 2" ends and the next path, that is, "path 3" is executed, the positions of the dots formed in "path 2" (circles numbered "2"). The timing of ejecting ink from each nozzle # 1 to # 8 is changed according to the position of the mark). The dots formed by the ink ejected from the nozzles # 1 to # 8 are oblique along the arrangement direction of the nozzles # 1 to # 8, as indicated by the circles numbered "3" in the figure. Although they are formed side by side, they are arranged so that they are aligned with the dots (circles numbered "2") formed by "pass 2".

Then, when "pass 4" is executed, each nozzle # 1 corresponds to the position of the dot formed in "pass 3" (the position of the circle numbered with "3"). The timing of ejecting ink from ~ # 8 is changed. The dots formed by the ink ejected from the nozzles # 1 to # 8 are oblique along the arrangement direction of the nozzles # 1 to # 8, as indicated by the circles numbered "4" in the figure. Although they are formed side by side, they are arranged so that they are aligned with the dots (circles numbered "3") formed by "pass 3".

The dots formed by the ink from each nozzle # 1 to # 8 (circles with numbers "1" to "4") are executed in each pass, that is, "pass 1" to "pass 4". Each time, it is formed with a gradual shift along one direction (in the present embodiment, the right direction in the figure).

In this way, when each pass, that is, "pass 1" to "pass 4" is executed, the ink ejection timing from each nozzle # 1 to # 8 is changed, so as shown in the figure, Although the point that the dots formed by the inks ejected from the nozzles # 1 to # 8 are formed diagonally is not solved, the arrangement of the dots can be made uniform. This does not have a significant effect on the composition of the printed image. From this, even when the head 21 is installed obliquely with respect to the moving direction of the carriage 41, it is possible to prevent the dot arrangement from being disturbed and suppress the deterioration of the image quality of the printed image. ..

=== Discharge timing change amount === The amount of change when changing the ink ejection timing from each of the nozzles # 1 to # 180 is obtained based on the amount of transport of the medium S and the inclination of the dots actually formed on the medium S.

FIG. 21 illustrates the relationship between the amount of the medium S conveyed, the inclination of the dots actually formed, and the amount of change in the ink ejection timing from the nozzles # 1 to # 180. Assuming that the transport amount of the medium S is "M", the inclination of the formed dots is "θ", and the change amount of the ink ejection timing is "L", the ink ejection timing change amount L has the following relationship. It can be obtained by Eq. (1). L = M × tan θ ............... (1) Assuming that the amount of medium S transported from the first pass (pass 1) to the N1th pass (pass N1) is M1, the ink ejection timing in the N1th pass (pass N1) The change amount L1 of can be obtained from the following relational expression (2). L1 = M1 × tan θ ............... (2) Further, the amount of change in the ink ejection timing L2 in the N2nd pass (pass N2) after the N1st pass (pass N1) can be obtained from the following relational expression (3). L2 = M2 × tan θ ............... (3) Here, the transport amount M (M1, M2) of the medium S increases sequentially as the path is executed, that is, as the printing process progresses. From this, the change amount L of the ink ejection timing is also gradually increased in the same manner. The amount of change in ink ejection timing "L" (L1, L2) required here represents a distance. When actually changing the ink ejection timing, an appropriate ink ejection timing is derived from the change amount "L" obtained here, and the ink is ejected.

=== How to change the discharge timing === The ink ejection timing from the nozzles # 1 to # 180 is changed by changing the output timing of the PTS signal from the controller 126 to the head drive unit 132.

FIG. 22 shows an example of the PTS signal output from the controller 126. Here, a case where dots are formed by four passes (path 1 to pass 4) will be described as an example. The PTS signal (1) indicates that it was output in the first path (path 1), and the PTS signal (2) indicates that it was output in the second path (path 2). Shown. The PTS signal (3) indicates that it was output in the third pass (path 3), and the PTS signal (4) was output in the fourth pass (path 4). Show things.

As shown in the figure, the timing at which pulses are generated in each of the PTS signals (1) to (4) is gradually deviated. This is because the medium S is transported each time the pass is executed, and the transport amount gradually increases. That is, as the amount of the medium S conveyed increases, it is necessary to increase the amount of change in the ink ejection timing in order to align the dots. Here, the timing at which the pulses of the PTS signals (1) to (4) are generated is gradually delayed each time the path is executed.

=== Controller processing === Each time the controller 126 executes the transport operation of the medium S, the controller 126 changes the output timing of the PTS signal from the controller 126 to the head drive unit 132 according to the transport amount of the transport operation. As a result, the ink ejection timings from the nozzles # 1 to # 180 of the nozzle rows 211C, 211M, 211Y, and 211K are changed. Here, a method in which the controller 126 acquires the amount of change in the output timing of the PTS signal will be described.

&lt;Method by calculation&gt; First, as one method, there is a method of obtaining the amount of change in the output timing of the PTS signal by calculation. An example of the method will be described. The controller 126 includes a calculation unit for calculating the amount of change in the output timing of the PTS signal. The controller 126 stores in the main memory 127 or the like data necessary for obtaining the amount of change in the output timing of the PTS signal according to the amount of the medium S conveyed. When the controller 126 obtains the amount of change in the output timing of the PTS signal, the controller 126 reads the data from the main memory 127 or the like, and changes the output timing of the PTS signal based on the read data and the amount of transport of the medium S. Calculate the amount. The amount of the medium S transported is obtained from the rotary encoder 134. Further, as the data required to obtain the change amount of the output timing of the PTS signal stored in the main memory 127 or the like, θ or tanθ indicating the inclination angle of the formed dots described in FIG. 22 is used. ], Etc., which refers to various correction data (corresponding to "predetermined correction information") necessary for obtaining the amount of change in the output timing of the PTS signal. The amount of change in the output timing of the PTS signal by the controller 126 is calculated by using, for example, the above-mentioned relational expression (1) or the like.

&lt;Method by table&gt; Here, a method of storing the change amount per pass in advance as a table in the main memory 127 or the like according to the transport amount per pass for each resolution of the image to be printed, the printing method, and the like will be described.

FIG. 23 shows an example of the table stored here. As shown in the figure, this table stores in advance the amount of change in the output timing of the PTS signal in the main memory 127 according to the resolution of the image to be printed, the printing method, and the like. That is, since the amount of transport of the medium S per pass differs depending on the resolution of the image to be printed and the printing method, the amount of change in the output timing of the PTS signal is stored in advance for each resolution and printing method of the image to be printed. Keep it.

The inkjet printer 1 according to the present embodiment stores five numerical values from α1 to α5 as the amount of change in the output timing of the PTS signal according to the resolution of the image to be printed and the printing method. When the type of resolution or the type of printing method of the image to be printed is larger or smaller than this, the number is not limited to these five numerical values from α1 to α5. That is, as the amount of change in the output timing of the PTS signal, the numerical value stored in the main memory 127 or the like is appropriately set according to the type of resolution and the type of printing method of the image to be printed.

When executing the path, the controller 126 reads the table data from the main memory 127 or the like, and sequentially changes the output timing of the PTS signal based on the read data.

=== Controller processing procedure === FIG. 24 is a flowchart showing an example of the processing procedure of the controller 126 at this time.

When the printing process is started, the controller 126 first checks whether or not the medium S is conveyed (S200). The check performed here may be executed before the transfer of the medium S is performed, or may be executed after the transfer of the medium S is performed. If it is found by this check that the medium S is not conveyed, the controller 126 sequentially executes the check until the medium S is conveyed. On the other hand, when it is found that the medium S is conveyed, the controller 126 then proceeds to step S202 to acquire the transferred amount of the medium S. The transport amount acquired here may be the transport amount obtained by one transport operation, or may be the total transport amount from the start of printing to the present.

After acquiring the transfer amount of the medium S in this way, the controller 126 acquires the change amount of the output timing of the PTS signal based on the acquired transfer amount of the medium S (S204). Here, the controller 126 calculates the output timing of the PTS signal based on the acquired transfer amount and various correction information such as information on the inclination angle of the formed dots (θ, tanθ, etc.). You may get the change amount of. Further, the controller 126 may read and acquire the change amount of the output timing of the PTS signal corresponding to the acquired transfer amount from the table or the like stored in the main memory 127 or the like based on the acquired transfer amount.

After acquiring the change amount of the output timing of the PTS signal in this way, the controller 126 then proceeds to step S206 and checks whether or not the movement of the carriage 41 has been started. Here, if the movement of the carriage 41 has not been started, the controller 126 executes the sequential check until the movement of the carriage 41 is started. On the other hand, when the movement of the carriage 41 is started, the controller 126 then proceeds to step S208, and starts outputting the PTS signal at a predetermined timing changed based on the acquired change amount.

Then, the controller 126 then proceeds to step S210 and checks whether or not the movement of the carriage 41 is completed. Here, if the movement of the carriage 41 is not completed, the controller 126 executes the check sequentially until the movement of the carriage 41 is completed. On the other hand, when the movement of the carriage 41 is started, the controller 126 then proceeds to step S212 and ends the output of the PTS signal.

After that, the controller 126 proceeds to step S214 and checks whether or not printing is completed. Here, if printing has been completed, the controller 126 ends the process as it is. On the other hand, if the printing is not completed, the controller 126 returns to step S200 again and checks whether or not the medium S is conveyed. The controller 126 repeatedly executes such a process until printing is completed.

=== Survey pattern === In the inkjet printer 1 according to the present embodiment, a survey is conducted to investigate whether or not the dots formed on the medium S by the inks ejected from the nozzles # 1 to # 180 are formed at an angle. Can be executed. This survey is carried out by forming a survey pattern on the medium S by the inkjet printer 1.

FIG. 25 shows an example of the survey pattern 500 formed here. The investigation pattern 500 has reference patterns X1 to X7 and comparison patterns Y1 to Y7. The reference patterns X1 to X7 are formed by a row of dots formed by inks ejected from the nozzles # 1 to # 180 based on the PTS signals output at predetermined timings as reference points. On the other hand, the comparison patterns Y1 to Y7 are formed by a row of dots formed by inks ejected from the nozzles # 1 to # 180 based on PTS signals having different output timings.

FIG. 26 shows an example of seven types of PTS signals (a) to (g) output to form the comparison patterns Y1 to Y7 with different output timings. The comparison patterns Y1 to Y7 are formed by the inks ejected from the nozzles # 1 to # 180 based on the PTS signals (a) to (g) at different timings at which such pulses are generated.

When investigating how much the dots formed on the medium by the ink ejected from the nozzles # 1 to # 180 are formed at an angle, the comparison patterns Y1 to Y7 are used as a reference. Select a pattern that exactly matches the patterns X1 to X7. That is, the comparison patterns Y1 to Y7 that exactly match the reference patterns X1 to X7 and form one straight line are selected. Here, since the comparison pattern Y3 exactly matches the reference pattern X3, the comparison pattern Y3 is selected.

In the vicinity of the comparison patterns Y1 to Y7 (here, below each comparison pattern Y1 to Y7), the symbols "# 1" to "# 7" are individually corresponding to the comparison patterns Y1 to Y7. It is attached. Here, since the comparison pattern Y3 is selected, the code # 3 corresponding to the comparison pattern Y3 is selected. If this code "# 3" is input to the inkjet printer 1, the head 21 is installed at an angle with respect to the moving direction of the carriage 41, and dots are formed obliquely on the medium S. Even in some cases, this can be corrected. In the inkjet printer 1 according to the present embodiment, when such correction information is input, this correction information is stored in the main memory 127 or the like, and this correction information is read out from the main memory 127 or the like when printing is executed. , Reflect in the print process.

It should be noted that such an adjustment pattern 500 may be formed at a factory or the like at the manufacturing stage of the inkjet printer 1, or may be appropriately performed by a user or a maintenance worker.

=== Summary === As described above, in the inkjet printer 1 according to the present embodiment, the controller 126 changes the output timing of the PTS signal according to the transfer amount of the transfer operation each time the transfer operation is executed. Therefore, each nozzle row 211C, The positions of the dots formed by the inks ejected from the nozzles # 1 to # 180 of 211M, 211Y, and 211K can be adjusted. For this reason, even when the head 21 is installed at an angle with respect to the moving direction of the carriage 41 and the dots formed on the medium S are formed at an angle. Since the dot formation position can be adjusted each time the transport operation is executed, it is possible to prevent the quality of the printed image from being significantly impaired. Thereby, even in such a case, the image quality of the printed image can be improved.

In particular, when the nozzles # 1 to # 180 in the nozzle row are arranged along a predetermined direction, the head 21 is installed at an angle with respect to the moving direction of the carriage 41, so that the medium is installed. Even when the dots formed on the S are formed at an oblique angle, deterioration of the image quality of the printed image can be suppressed.

Further, if a calculation unit for calculating the change amount when changing the output timing of the PTS signal is provided, the change amount can be easily obtained. Further, if a table in which the transport amount of the medium S and the change amount of the output timing of the PTS signal are associated with each other is provided, the change amount can be easily acquired.

Further, it is possible to form a survey pattern 500 for investigating how much the dots formed on the medium S by the inks ejected from the nozzles # 1 to # 180 are formed at an angle. , The appropriate amount of change in the output timing of the PTS signal can be easily investigated.

=== Configuration of printing system, etc. === Next, an embodiment of the printing system according to the present invention will be described by exemplifying a case where the inkjet printer 1 is provided as the printing apparatus. FIG. 27 shows an external configuration of an embodiment of the printing system according to the present invention. The printing system 300 includes a computer 140, a display device 304, and an input device 306. The computer 140 is composed of various computers such as a personal computer.

The computer 140 includes a reading device 312 such as an FD drive device 314 and a CD-ROM drive device 316. In addition to this, the computer 140 may include, for example, an MO (Magnet Optical) disk drive device, a DVD drive device, or the like. Further, the display device 304 is composed of various display devices such as a CRT display, a plasma display, and a liquid crystal display. The input device 306 is composed of a keyboard 308, a mouse 310, and the like.

FIG. 28 is a block configuration diagram showing an example of the system configuration of the printing system of the present embodiment. The computer 140 includes a CPU 318, a memory 320, and a hard disk drive 322, in addition to a reading device 312 such as an FD drive device 314 and a CD-ROM drive device 316.

The CPU 318 controls the entire computer 140. In addition, various data are stored in the memory 320. A printer driver or the like is installed in the hard disk drive 322 as a program for controlling a printing device such as the inkjet printer 1 of the present embodiment. The CPU 318 reads a program such as a printer driver stored in the hard disk drive 322 and operates according to the program. Further, a display device 304, an input device 306, an inkjet printer 1, and the like installed outside the computer 140 are connected to the CPU 318.

The printing system 300 realized in this way is a system superior to the conventional system as a whole system.

=== Other embodiments === The printing apparatus such as a printer according to the present invention has been described above based on one embodiment, but the above-described embodiment is for facilitating the understanding of the present invention, and the present invention is limited and interpreted. Not for doing. It goes without saying that the present invention can be modified or improved without departing from its gist, and the present invention includes its equivalents. In particular, even the embodiments described below are included in the printing apparatus according to the present invention.

&lt;About the transport mechanism&gt; In the above-described embodiment, a configuration including a paper transport motor 15, a transport roller 17A, a paper discharge roller 17B, and the like is disclosed as the "convey mechanism", but such a mechanism is provided in the "convey mechanism". The mechanism is not limited to the above, and any mechanism may be used as long as it can convey the medium S.

&lt;About the nozzle&gt; In the above-described embodiment, the nozzles are arranged in a straight line along a predetermined direction in a row, but in the case of a "nozzle", the nozzles need to be arranged in a straight line in this way. There is no. Further, the "nozzles" need not be arranged in a straight line in a row as long as they are arranged along a predetermined direction, and may be arranged in a staggered pattern, for example.

&lt;About the ink ejection mechanism&gt; In the above-described embodiment, a mechanism for ejecting ink by using a piezo element as a piezoelectric element has been introduced, but the mechanism for ejecting ink is not limited to a mechanism for ejecting ink by such a method. If it is a mechanism that ejects ink, for example, a method that ejects ink by generating bubbles in the nozzle by heat or the like, various other methods, and if it is a mechanism that ejects ink, any method is adopted. It doesn't matter if you have it.

&lt;About moving discharge operation&gt; In the above-described embodiment, the "moving ejection operation" has been described as an operation of ejecting ink toward the medium S when the carriage 41 moves once along the carriage moving direction, that is, a so-called path. The "moving discharge operation" is not necessarily limited to the operation when the carriage moves once in this way. That is, even when the carriage 41 moves along the movement direction of the carriage, then temporarily stops and then starts moving again, or when the carriage 41 moves back and forth, these series of operations are also referred to as a moving discharge operation. That is, all the moving ejection operations executed between the media conveying operations are included in the "moving ejection operation".

&lt;About the signal output section&gt; In the above-described embodiment, the controller 126 is exemplified as a signal output unit that outputs a signal (PTS signal or the like), but in the signal output unit, the controller 126 that controls the entire printing apparatus is used. Not limited to. That is, a dedicated circuit or the like for outputting a signal (PTS signal or the like) may be separately provided, or a signal output unit for outputting a signal (PTS signal or the like) may be provided on the head drive unit 132 or the like. Good.

&lt;About signals&gt; In the above-described embodiment, the PTS signal has been described as an example of "a reference signal for ejecting ink from a plurality of nozzles at the same timing", but such a signal is described. Not limited to PTS signals. That is, any form of signal may be used as long as it is a "reference signal for ejecting ink from a plurality of nozzles at the same timing".

&lt;About printing method&gt; In the above-described embodiment, the interlace method and the overlap method have been described as the "printing method", but the "printing method" is not limited to these printing methods. That is, the "printing method" includes a method other than these printing methods, specifically, a band printing method, a draft printing method, and the like.

&lt;Regarding predetermined correction information&gt; In the above-described embodiment, "θ" and "tanθ" indicating the inclination angle of the formed dots have been described as "predetermined correction information", but the "predetermined correction information" has been described. , Not limited to such correction information. That is, the "predetermined correction information" may be the amount of change in the output timing of the PTS signal in a specific transfer amount, or may be the ratio of the transfer amount and the change amount. In short, the "predetermined correction information" includes all information other than the amount of transport of the medium S, which is necessary for obtaining the amount of change in the output timing of the PTS signal.

&lt;About survey patterns&gt; In the above-described embodiment, as the survey pattern, a pattern having reference patterns X1 to X7 and comparison patterns Y1 to Y7 has been described as an example, but in the survey pattern, such a pattern has been described. Not limited to. That is, any pattern formed on the medium S for investigating an appropriate change amount of the output timing of the PTS signal or the like is included in the investigation pattern.

&lt;About ink&gt; The ink used may be a pigment ink, or may be various other inks such as a dye ink. Regarding the color of the ink, in addition to the above-mentioned yellow (Y), magenta (M), cyan (C), and black (K), light cyan (LC), light magenta (LM), dark yellow (DY), for example. Other colors of ink, such as red, violet, blue, and green, may be used.

&lt;About dots&gt; In the above-described embodiment, dots having a substantially circular shape are formed as the dots to be formed, but they may have an elliptical shape or any other shape. That is, dots of any shape and shape may be used as long as they constitute pixels of the image to be printed.

&lt;About printing equipment&gt; In the above-described embodiment, the printing apparatus according to the present invention has been described by taking the case of the inkjet printer 1 as described above as an example. However, the printing apparatus is not limited to such a printing apparatus, and ink is ejected by another method. It may be an inkjet printer.

&lt;About the medium&gt; Regarding medium S, plain paper, matte paper, cut paper, glossy paper, roll paper, paper, photo paper, roll type photo paper, etc., as well as film materials and cloth materials such as OHP film and glossy film. , Metal plate material, etc. may be used. That is, any medium may be used as long as it can be printed.

<figref num="1">The perspective view of one Embodiment of the printing apparatus which concerns on this invention.</figref><figref num="2">The perspective view explaining the internal structure of a printing apparatus.</figref><figref num="3">The cross-sectional view which shows the transport part of a printing apparatus.</figref><figref num="4">The block block diagram which shows the system structure of a printing apparatus.</figref><figref num="5">Explanatory drawing which shows arrangement of nozzles of a head.</figref><figref num="6">The figure which roughly explained the structure of the linear encoder.</figref><figref num="7">The figure which schematically explained the structure of the detection part of a linear encoder.</figref><figref num="8">FIG. 8A is a timing chart showing the output waveform of the linear encoder at the time of normal rotation, and FIG. 8B is a timing chart showing the output waveform of the linear encoder at the time of reverse rotation.</figref><figref num="9">The figure explaining the structure of the rotary encoder.</figref><figref num="10">The figure explaining an example of the drive circuit of a head.</figref><figref num="11">It is a timing chart of each signal.</figref><figref num="12">It is a timing chart of each signal.</figref><figref num="13">A flowchart illustrating an example of printing processing.</figref><figref num="14">14A and 14B are explanatory views illustrating an example of an image printing procedure by the interlace method.</figref><figref num="15">15A and 15B are explanatory views illustrating an image printing procedure by another interlace method.</figref><figref num="16">16A and 16B are explanatory views illustrating an example of an image printing procedure by the overlap method.</figref><figref num="17">Explanatory drawing for explaining a conventional problem.</figref><figref num="18">Explanatory drawing for explaining a conventional problem.</figref><figref num="19">Explanatory drawing explaining the arrangement state of dots at the time of printing normally.</figref><figref num="20">Explanatory drawing schematically explaining the printing method of this invention.</figref><figref num="21">The explanatory view explaining the change amount of the ink ejection timing.</figref><figref num="22">The figure for demonstrating an example of a PTS signal.</figref><figref num="23">The figure explaining an example of the table of this invention.</figref><figref num="24">A flowchart illustrating an example of a controller processing procedure.</figref><figref num="25">The figure which shows an example of the investigation pattern of this invention.</figref><figref num="26">Diagram of the PTS signal for forming the survey pattern.</figref><figref num="27">The perspective view which shows the appearance of an example of the printing system which concerns on this invention.</figref><figref num="28">The block block diagram which shows the system structure of an example of the printing system which concerns on this invention.</figref>

Code description

1 Inkjet printer, 2 Operation panel, 3 Paper output section, 4 Paper feed section, 5 operation buttons, 6 indicator lamps, 7 output trays, 8 paper feed trays, 13 Paper Feed Roller, 14 Platen, 15 Conveyor Motor, 17A Conveyor Roller, 17B paper ejection roller, 18A free roller, 18B free roller, 21 heads, 31 pumping device, 35 capping device, 41 carriage, 42 carriage motor, 44 pulley, 45 timing belt, 46 guide rail, 48 ink cartridges, 49 cartridge mounts, 51 linear encoders, 53 Paper detection sensor, 122 buffer memory, 124 image buffer, 126 controller, 127 main memory, 128 carriage motor control unit, 129 Communication interface, 130 Transport control unit, 132 Head drive unit, 134 rotary encoder, 140 computer, 211 Nozzle Row, 211Y Yellow Nozzle Row, 211M Magenta Nozzle Row, 211C cyan nozzle row, 211K Black nozzle row, 224 1st shift register, 226 2nd shift register, 228 latch circuit group, 230 data selector, 300 printing system, 304 display device, 306 input device, 308 keyboard, 310 mouse, 312 reader, 314 FD drive device, 316 CD-ROM drive device, 318 CPU, 320 memory, 322 hard disk drive, 402 rotary encoder code plate, 404 detector, 408 large gear, 410 small gears, 452 light emitting diodes, 454 collimator lenses, 456 detection processing unit, 458 photodiode, 460 signal processing circuit, 462A Comparator, 462B Comparator, 464 Linear encoder code plate, 466 detector, 500 investigation pattern,