Print system for long matter

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention relates to a printing system for performing long-length printing in which an image is printed on a large-format printing medium.

【0002】

[Conventional technology]

Conventionally, as an output device of a computer, an inkjet printer that records an image by forming dots with inks of several colors ejected from a plurality of nozzles provided in the head has been proposed, and an image processed by a computer or the like can be printed. Widely used for printing in multiple colors and multiple gradations. With such a printer, it is also possible to print an image on a large-format printing medium such as roll paper (hereinafter, such printing is referred to as long printing). For example, an image can be printed on a printing medium that extends for several tens of meters, such as a banner.

【0003】

Generally, there is a limit to the amount of data that can be handled by an application program that provides image data. Therefore, when performing long printing, the printer driver is usually divided into a plurality of pages and supplied with data for printing. In normal printing, there is a margin between multiple pages, but in long printing, by eliminating this margin, continuous images can be printed while receiving data divided into multiple pages. It is possible.

【0004】

By the way, in an inkjet printer, in order to improve the printing speed, it is usual to use a head in which a large number of nozzles are arranged in the sub-scanning direction. In a printer using such a head, there is a technique called "interlace method" as one of the recording methods for improving the image quality.

【0005】

FIG. 16 is an explanatory diagram showing an example of the interlaced method. In the example of FIG. 16, an example using three nozzles with a pitch of 2 dots is shown. In this example, in the first main scan, the dots of each raster are formed by the 2nd and 3rd nozzles. Nozzles do not form dots with Nozzle 1. Next, after feeding paper for 3 rasters, each raster is formed using nozzles 1 to 3 while performing the second main scan. After that, the image is recorded by repeatedly executing the paper feed for 3 rasters and the formation of rasters by the main scan in the same manner. As is clear here, the reason why the raster was not formed by the first nozzle in the first main scan is that the raster adjacent under the raster cannot be formed in the second and subsequent main scans.

【0006】

The interlaced method is a method of recording an image while intermittently forming a raster in the sub-scanning direction in this way. This interlaced method has an advantage that variations such as nozzle pitch and ink ejection characteristics can be dispersed on a recorded image. Therefore, even if there are variations in the nozzle pitch and ejection characteristics, it is possible to alleviate these effects and improve the image quality. In FIG. 16, a case where each raster is formed by one main scan at a specific nozzle pitch has been described, but recording by an interlace method with various feed amounts depending on the nozzle pitch, the number of nozzles, the number of repeated scans, and the like. Is possible.

【0007】

Interlaced recording also applies to long prints. However, in the recording by the interlace method, as is clear from FIG. 16, there are several rasters above and below, respectively, which cannot completely form an image. When performing long printing, it is necessary to print the image without margins between pages, so the presence of rasters that cannot form the image is unacceptable. Therefore, conventionally, when long printing is specified so as to avoid the occurrence of rasters that cannot form an image, it is called upper end processing and lower end processing as shown below at the upper and lower sides of each page. Printing was executed by performing sub-scanning with an irregular feed amount.

【0008】

FIG. 17 shows the state of conventional long printing. As shown in the figure, image data divided into N pages is printed in a predetermined area of a continuous printing medium. At this time, as shown in the figure, the upper end processing is performed on the upper side of each page, and the lower end processing is performed on the lower side to realize printing in which there is no margin between pages.

【0009】

An example of lower end processing is shown in FIG. Here, a head having seven nozzles at a 4-dot pitch in the sub-scanning direction will be described as an example. The solid circle in the figure means the nozzle. The number in the circle is the nozzle number. The dashed circles are shown for convenience of nozzle pitch. The figure shows the position of the head in the sub-scanning direction for each main scan in order from the left side. As shown in the figure, sub-scans equivalent to 7 rasters are executed for each main scan until the lower end processing is started. When the lower end processing is started, first, 4 rasters are fed, then 3 rasters are fed 4 times, and then 1 raster is finely fed 4 times. By performing such feed, an image can be recorded up to the raster where the 7th nozzle is located at the time of the final main scan without causing the raster to drop out.

【0010】

Next, an example of upper end processing is shown in FIG. The meanings of the symbols in the figure are the same as in FIG. In the upper end processing, first, the minute feed of 1 raster is executed 4 times, then the feed of 3 rasters is executed 4 times, and the feed of 4 rasters is performed. After this, it shifts to standard feed, that is, feed of 7 rasters at a time. By doing so, as shown in FIG. 19, the image can be recorded from the raster where the first nozzle is located in the first main scan.

【0011】

[Problems to be Solved by the Invention]

However, in the conventional long printing, the dot formation position shifts, so-called banding, occurs at the boundary portion of each page. As described above, in the conventional long printing, the bottom edge processing is performed to print the image to the bottom edge of each page, and then the sub-scanning of the large feed is performed to print the image of the subsequent page. For example, when the bottom edge processing shown in FIG. 18 is executed and the recording of the image on the first page is completed, the size of the entire head is set to start recording of the raster immediately adjacent to the lower side in the manner shown in FIG. Perform a sub-scan with a corresponding feed amount. In the examples of FIGS. 18 and 19, since seven nozzles are provided at a 4-dot pitch, sub-scanning for 25 rasters is performed at the page boundary.

【0012】

Generally, the accuracy of the sub-scan decreases as the feed amount increases. In a conventional large-format printer, the distance between the raster at the bottom of the previous page and the raster at the top of the next page may be extremely different from the distance between other rasters due to this decrease in feed accuracy. For this reason, banding may occur at the boundary of the page.

【0013】

Further, in the conventional long printing, banding occurs even in the area of the lower end processing and the upper end processing. As shown in FIGS. 18 and 19, in order to complete the image of each page without margins, it is necessary to perform a fine feed of 1 raster in the lower end processing and the upper end processing. A plurality of rasters formed by the same nozzle appear adjacent to each other in the region where the minute feed is performed. For example, all four rasters located at the lower end of FIG. 18 are formed by nozzle 7. In addition, all four rasters located at the upper end of FIG. 19 are formed by the first nozzle. In this case, if nozzles 1 and 7 are displaced in the ink ejection direction due to mechanical manufacturing errors, etc., the formation positions of the four rasters formed by each nozzle will be displaced together. .. Such a deviation is visually recognized as banding.

【0014】

The reason why the upper end processing, the lower end processing, and the fine feed are performed in the conventional long printing is that the conventional printing apparatus is not allowed to perform sub-scanning of the head across the boundary of each page. At the point. Since printing is performed while receiving data sequentially, it is not possible to determine whether or not the next page exists during printing regardless of whether it is long printing or normal printing. Therefore, when the head is sub-scanned across the boundary, it becomes necessary to return the print medium in the direction opposite to the sub-scanning at the start of printing on the next page. For example, according to the example shown in FIG. 16, the printable area is the area below the raster where the second nozzle is located in the first main scan. However, if the head is unconditionally allowed to be sub-scanned across the boundary, the position of Nozzle 2 is located below the uppermost raster on the next page where printing should start at the end of printing on the previous page. It ends up.

【0015】

In the conventional printing apparatus, in consideration of the above circumstances, as shown in FIG. 17, sub-scanning is performed so that the head does not cross the boundary of each page. Therefore, in the vicinity of the boundary of each page, sub-scanning is performed as the upper end processing and the lower end processing with a feed amount different from the feed amount periodically performed in the normal region.

【0016】

However, as described above, banding occurs in the boundary portion of the plurality of pages and the area where the upper end processing and the lower end processing are performed, and this banding impairs the image quality in long printing. The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a technique for eliminating banding that occurs near the boundary of each page and improving image quality in long printing. ..

【0017】

[Means for solving problems and their actions / effects]

In order to solve at least a part of the above-mentioned problems, the present invention has adopted the following configuration. The print control device of the present invention includes a head in which a plurality of dot forming elements are arranged at predetermined intervals in the sub-scanning direction, and repeatedly executes main scanning and sub-scanning to supply an image to a printing unit that prints an image on a printing medium. As the print data to be printed, it is a print control device that generates data for printing an image input over a plurality of pages arranged in the sub-scanning direction, and separates the image data of the image from the page. An input means for sequentially inputting delimiter data for specifying the above and end data indicating the end of the image data, an instruction input means for inputting an execution instruction for long printing without providing a margin between pages, and the printing unit. The print data generation means is provided with a print data generation means for generating print data to be supplied to the data, and the print data generation means has a fixed cycle regardless of whether or not the image is completed for each page when long printing is instructed. Rasta data generation means that generates feed data in which the sub-scanning is repeated according to the feed amount of the above, and raster data generation that generates raster data that specifies a dot formation state by the head during the main scanning based on the image data. The gist is that it is a means provided with means. When the print data generated by the print control device of the present invention is output to the printing unit, the printing unit performs main scanning and sub-scanning based on the printing data to print an image. The operation of the present invention will be described.

【0018】

In the conventional printing apparatus, as described above, the formation of the image is completed for each page. In the conventional printing apparatus, printing is executed while sequentially receiving the supply of image data, and when a signal instructing a page break is input at the end of the image data, page break is executed according to the signal. It is not possible to determine whether or not the next page exists from the signal instructing the page break. Therefore, conventionally, the formation of an image has been completed for each page so that the printing of each page can be completed regardless of whether or not the next page exists. In addition, as described above, in order to avoid having to return the print medium in the direction opposite to the sub-scanning at the start of printing of each page, the head does not cross the boundary of each page and is near the boundary of each page. In the above, as the upper end processing and the lower end processing, the sub-scanning is performed with a feed amount different from the feed amount periodically performed in the normal region.

【0019】

On the other hand, in the present invention, when long printing is instructed, sub-scanning is performed with a feed amount repeated at a fixed cycle regardless of whether or not the image is completed for each page, and the image is printed. If the sub-scanning is performed with such a feed amount, the head may be positioned across the page boundary. In such a case, in such a case, the image data of each page is determined according to the position of the raster forming element. To perform printing. The image data of the previous page is supplied to the forming element located on the previous page across the boundary of the page, and the image data of the subsequent page is supplied to the forming element located on the subsequent page. When the back page does not exist, the image data is supplied only to the forming element located on the front page.

【0020】

In the present invention, when performing long printing, the image is printed while maintaining the feed amount at a fixed cycle regardless of whether the image is completed for each page, so that the feed amount is large at the boundary portion. It is possible to avoid performing sub-scanning. Further, since it is not necessary to complete the printing for each page, it is not necessary to perform the lower end processing including the fine feed and the upper end processing. Therefore, in the present invention, it is possible to avoid the occurrence of banding at the boundary portion of the page and improve the image quality. Moreover, since it is sufficient to maintain the feed amount at a constant cycle at all times, there is an advantage that the printing control process becomes very simple. The present invention is particularly effective when printing a continuous image (hereinafter, referred to as a continuous image) including a page boundary portion.

【0021】

In general, long printing instructions are usually given to a very long printing medium such as roll paper. When the size of the print medium does not have a margin for the area on which the image is printed, if the sub-scanning is performed up to the vicinity of the end of the print medium, the feed accuracy may be significantly lowered depending on the sub-scanning mechanism. On the other hand, when performing long printing, the length of the printing paper is usually sufficient. The present invention has been made in view of such characteristics in long-length printing, and states that "at least on the final page, it should be prohibited to position the head beyond the predetermined size of the print medium." It was realized by breaking the conventional stereotypes. As a result, it has become possible to improve the image quality while simplifying the long printing process. Since the processing is simplified, it is naturally possible to improve the printing speed.

【0022】

Here, the feed amount at a constant cycle does not necessarily mean a constant feed amount. Depending on the number and spacing of the raster forming elements, the image may be printed using two or more feed rates periodically. Such periodic use is also included in the feed amount of a fixed cycle. In the present invention, it is not necessary to maintain the feed amount at a fixed cycle strictly in all regions, and an exceptional feed amount may be used in a small part of the regions.

【0023】

For example, in the first page of the plurality of pages, the feed data setting means has a feed amount smaller than the average feed amount repeated in the fixed cycle and a feed amount of the fixed cycle prior to the feed amount repeated in the fixed cycle. The feed amount may be a means for setting the feed amount capable of executing the main scan in a predetermined area outside the printable area without causing the raster to drop out. In this way, the upper end of the first page can be subjected to so-called upper end processing as in the conventional case, and the printable area can be expanded at the upper end portion of the first page. This is an area in which the predetermined area is expanded. The actual feed amount can be variously set according to the range of a predetermined region, the pitch of the dot forming elements, the number of main scans required for forming each raster, and the like.

【0024】

The present invention can be more specifically configured in the following aspects. When the delimited data is input, the raster data generation means waits for the input of the image data of the page following the delimited data to generate the raster data, and when the terminal data is input, further It is a print control device that is a means for generating the raster data without waiting for input of image data. In this way, when the head is positioned across the page boundary, the image can be printed appropriately depending on whether or not there is a page following the boundary. As for the structure of the delimiter data and the termination data, various formats of data can be applied as long as they can be clearly distinguished from general image data.

【0025】

Further, as another aspect, the print data generation means may be a means for generating the print data by setting the size of the print medium to a value sufficiently larger than that of the plurality of pages. it can.

【0026】

In this way, the image data divided into a plurality of pages can be treated virtually like the data existing on one page. Moreover, by setting the size of the print medium to a sufficiently large value, long printing can be realized by using the same processing as the normal printing processing.

【0027】

In the present invention, long printing may be performed exclusively, but the instruction input means selectively inputs the long printing execution instruction and the normal printing execution instruction in which a margin is provided for each page. The feed data setting means is a means for setting a feed amount capable of executing the main scan for each page without causing a raster omission when normal printing is instructed, and the raster data generation. The means may be means for generating raster data of each page based on the image data input before the delimiter data. By doing so, it is possible to select and execute normal printing in which a margin is provided for each page and long printing, and the usefulness of the printing system can be improved.

【0028】

In addition to being configured as the above-mentioned print control device, the present invention can also be configured as various printing devices including the above-mentioned print control device and the above-mentioned printing unit as an invention that makes the main part the same. Such a printing apparatus further includes a back-feeding means for feeding the print medium excessively fed by printing the image on the last page of the plurality of pages to a position suitable for the next printing start in the direction opposite to that at the time of printing. It is also desirable to make it.

【0029】

As described above, in the present invention, even on the final page of the image, printing is executed while maintaining the feed amount at a fixed cycle without performing the lower end processing. Therefore, a useless area may be generated in the area following the final page on the print medium. If the above-mentioned back-feeding means is provided, the wasted area once generated can be effectively utilized for the next printing by back-feeding the print medium. The reverse feed means can be, for example, a means for determining the size of the wasted area generated by the excessive feed from the process of the sub-scanning and returning the size to a position suitable for the next printing start. Further, the print medium may be back-fed to the state before being supplied to the printing apparatus, and the print medium may be supplied again. Further, such reverse feeding may be performed when the printing of the image is completed, or may be performed prior to the start of the next printing.

【0030】

The present invention may be further configured as a print control method or a printing method, or may be configured in various modes such as a recording medium on which a program for generating data supplied to the above-mentioned printing unit is recorded, the program itself, and the like. Can be done.

【0031】

The storage medium includes a flexible disk, a CD-ROM, a magneto-optical disk, an IC card, a ROM cartridge, a punch card, a printed matter on which a code such as a bar code is printed, and an internal storage device of a computer (memory such as RAM or ROM). ) And various computer-readable media such as external storage can be used.

【0032】

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described in the following order based on examples. A. Overall configuration of the device: B. Software configuration: C. Printer configuration: D. Print control: E. Dot formation: F. Effects and variants: [0033]

A. Device Configuration: FIG. 1 is a block diagram showing the configuration of a printing device as an embodiment of the present invention. As shown, the computer 90 is connected to the color printer 22. When a predetermined program is loaded and executed on the computer 90, it functions as a print control device that controls the printer 22. The computer 90 includes the following parts connected to each other by a bus 80, centering on a CPU 81, a ROM 82, and a RAM 83 that execute various arithmetic processes according to a program. The input interface 84 controls the input of signals from the keyboard 14 and the like, and the output interface 85 controls the output of data to the printer 22. The CRTC86 controls the signal output to the color-displayable CRT21, and the disk controller (DDC) 87 controls the transfer of data to and from the hard disk 16, the CD-ROM drive 15, or a flexible disk drive (not shown). The hard disk 16 stores various programs loaded and executed in RAM 83 and various programs provided in the form of device drivers.

【0034】

In addition, a serial input / output interface (SIO) 88 is connected to the bus 80. This SIO88 is connected to the modem 18, and is connected to the public telephone line PNT via the modem 18. The computer 90 is connected to an external network via the SIO88 and the modem 18, and various programs can be downloaded to the hard disk 16 by connecting to a specific server SV. It is also possible to load the necessary programs on a flexible disk FD or CD-ROM and have the computer 90 execute them.

【0035】

The printer 22 is an inkjet printer. Although the detailed configuration will be described later, the head provided with a plurality of nozzles for ejecting ink is reciprocated in one direction of the printing paper for main scanning, and the head and the printing paper are relative to each other in a direction orthogonal to the main scanning. The image is printed by performing a sub-scanning that moves around. From the computer 90 to the printer 22, raster data that specifies which pixel each nozzle forms a dot during the main scan, feed amount data that specifies the feed amount of the sub scan, and the like are output as print data. .. The printer 22 executes the main scan and the sub scan based on the print data.

【0036】

B. Software configuration: Figure 2 is a block diagram showing the software configuration of the printing device. On computer 90, application program 95 is running under a given operating system. The video driver 91 and the printer driver 96 are incorporated in the operating system, and the application program 95 outputs the print data FNL for transfer to the printer 22 via these drivers. The application program 95 generates an image for printing on a large-format print medium such as a banner according to an instruction from the keyboard 14, etc., and displays the image on the CRT display 21 via the video driver 91. ing. The image data ORG generated by the application program 95 is data composed of three color components of red (R), green (G), and blue (B).

【0037】

When this application program 95 issues a print instruction, the spooler 97 of the printer driver 96 of the computer 90 receives the image data ORG from the application program 95 in the form of a set of drawing instructions and stores it in the spool file SF. Since the amount of image data for a large-format print medium generated by the application program 95 is enormous, it cannot be collectively transferred to the printer driver 96. According to the restrictions on the operating system, the application program 95 divides the image data into pages of a predetermined size and sequentially transfers them to the printer driver 96. The despooler 98 provided in the printer driver 96 raster-processes the drawing instructions stored in the spool file SF and converts them into image data having R, G, and B gradation values for each pixel.

【0038】

In addition to the spooler 97, spool file SF, and despooler 98, the printer driver 96 includes a color conversion module 99, a halftone module 100, a feed amount setting unit 101, and a data output unit 102. The color conversion module 99 changes the color components of the image data from R, G, B to the color components (here, cyan, magenta, yellow, and black colors) that can be expressed by the printer 22 according to the color conversion table LUT prepared in advance. to correct. The printer 22 of this embodiment can take only two values of dot on / off for each pixel. Therefore, the halftone module 100 sets the on / off of the dots for each pixel so that the gradation value of the image data corrected by the dispersibility of the dots formed by the printer 22 can be expressed.

【0039】

The feed amount setting unit 101 sets the sub-scanning amount according to the print mode. As a printing mode, the printing apparatus of this embodiment has a long printing mode for printing one continuous image on a large-format printing medium and a normal printing mode for printing an image for each page specified by the application. There is. The sub-scanning amount of each page corresponding to each printing mode is set in advance in the feed amount table SS. The feed amount setting unit 101 refers to this feed amount table and sets the feed amount according to each print mode. Further, the position of each nozzle of the printer 22 is determined based on the setting of the sub-scanning amount, and the raster to be printed is selected.

【0040】

The data output unit 102 rearranges the print data of each raster in the order of output to the head according to the main scanning direction of the head. The printer driver 96 outputs the image data subjected to the above processing and the feed amount data for specifying the feed amount of the sub-scan to the printer 22 as print data FNL.

【0041】

In the printer 22, the input unit 201 receives the print data FNL output from the computer 90 and temporarily stores it in the buffer 202. The data in the buffer 202 is output to the main scanning unit 203. The main scanning unit 203 ejects ink based on the print data while performing the main scanning of the head. Further, when the raster is formed by the main scanning unit 203, the sub-scanning unit 204 conveys the printing paper with the sub-scanning amount specified by the printer driver 96. The input unit 201 sequentially inputs the data of the remaining portion while the main scanning unit 203 and the sub scanning unit 204 are executing printing.

【0042】

C. Printer Configuration: Next, the schematic configuration of the printer 22 will be described with reference to FIG. As shown in the figure, the printer 22 has a mechanism for transporting the paper P by the paper feed motor 23, a mechanism for reciprocating the carriage 31 in the axial direction of the platen 26 by the carriage motor 24, and a print head mounted on the carriage 31. It is composed of a mechanism that drives 28 to eject ink and form dots, and a control circuit 40 that controls the exchange of signals with the paper feed motor 23, carriage motor 24, printhead 28, and operation panel 32. ..

【0043】

The mechanism for reciprocating the carriage 31 in the axial direction of the platen 26 is an endless drive belt between the sliding shaft 34, which is erected in parallel with the axis of the platen 26 and holds the carriage 31 slidably, and the carriage motor 24. It is composed of a pulley 38 on which 36 is stretched, a position detection sensor 39 for detecting the origin position of the carriage 31, and the like.

【0044】

The carriage 31 can be equipped with a cartridge 71 for black ink (Bk) and a cartridge 72 for color ink containing three colors of ink, cyan (C), magenta (M), and yellow (Y). .. A total of four ink ejection heads 61 to 64 are formed on the print head 28 at the bottom of the carriage 31. When the black (Bk) ink cartridge 71 and the color ink cartridge 72 are mounted on the carriage 31 from above, ink can be supplied from each cartridge to the ejection heads 61 to 64.

【0045】

The printer 22 of this embodiment can supply cut sheet paper or roll paper as printing paper P. Although not shown, the roll paper is pivotally supported by the holding portion and supplied to the printer 22. When the printing of the image is completed, the user cuts the roll paper. For cutting, a mechanism for automatically cutting the paper by a signal from the control circuit 40 may be provided. By using roll paper, the printer 22 of this embodiment can print an image over several tens of meters.

【0046】

FIG. 4 is an explanatory diagram showing the arrangement of the inkjet nozzles Nz in the ink ejection heads 61 to 64. The arrangement of these nozzles consists of four sets of nozzle arrays that eject ink for each color, and 48 nozzles Nz are arranged in a staggered pattern with a constant nozzle pitch k. The positions of the nozzle arrays in the sub-scanning direction coincide with each other. The nozzle pitch k of this embodiment corresponds to 6 dots.

【0047】

A mechanism for ejecting ink and forming dots will be described. FIG. 5 is an explanatory diagram showing a schematic configuration inside the ink ejection head 28. For convenience of illustration, the yellow head is not shown. In the 48 nozzles Nz provided on the heads 61 to 64 of each color, a piezo element PE is arranged for each nozzle at a position in contact with the ink passage 68 that guides the ink to the nozzle Nz. Figure 5 shows in detail the structure of the piezo element PE and the nozzle Nz. As is well known, the piezo element PE is an element in which the crystal structure is distorted by the application of a voltage and the conversion of electric-mechanical energy is performed at an extremely high speed. When a voltage having a predetermined time width is applied between the electrodes provided at both ends of the piezo element PE, the piezo element PE is stretched by the voltage application time as shown in the figure, and one side wall of the ink passage 68 is deformed. As a result, the volume of the ink passage 68 contracts according to the expansion of the piezo element PE, and the ink corresponding to this contraction becomes particles Ip and is ejected from the tip of the nozzle Nz at high speed. Printing is performed by permeating the ink particles Ip into the paper P mounted on the platen 26.

【0048】

Next, the internal configuration of the control circuit 40 of the printer 22 will be described. FIG. 6 is an explanatory diagram showing the internal configuration of the control circuit 40. As shown in the figure, inside the control circuit 40, in addition to the CPU 41, PROM 42, and RAM 43, a PC interface 44 that exchanges data with the computer 90, a paper feed motor 23, a carriage motor 24, an operation panel 32, and the like are connected. A peripheral input / output unit (PIO) 45 for exchanging signals, a timer 46 for measuring time, and a drive buffer 47 for outputting dot on / off signals to heads 61 to 64 are provided, and these elements are provided. And the circuits are interconnected by bus 48. The control circuit 40 also includes a transmitter 51 that outputs a drive waveform for driving the piezo element PE of each nozzle at a predetermined frequency, and a distributor 55 that distributes the output from the transmitter 51 to the heads 61 to 64. It is provided.

【0049】

The control circuit 40 receives the print data processed by the computer 90, temporarily stores the print data in the RAM 43, and outputs the print data to the drive buffer 47 at a predetermined timing. From the drive buffer 47, data indicating on / off of dots for each nozzle is output to the distribution output device 55. As a result, a drive waveform for driving the piezo element PE is output to the nozzle on which the dots should be formed, and the dots are formed.

【0050】

In this embodiment, as described above, the printer 22 provided with the head for ejecting ink using the piezo element PE is used, but a printer for ejecting ink by another method may be used. For example, it may be applied to a printer of a type in which a heater arranged in an ink passage is energized and ink is ejected by bubbles generated in the ink passage. In addition to ejecting ink to form dots, it can also be applied to various types of printers such as so-called thermal transfer type printers, sublimation type printers, and dot impact type printers.

【0051】

D. Print control: Next, the print control process in this embodiment will be described. Here, a process of printing an image on a large-format print medium will be described. In this embodiment, a normal mode and a long mode are provided as print modes in such a case. Figure 7 (a) shows how the image is printed in the normal mode. As shown in the figure, an image is printed with a margin provided for each page. Further, in order to expand the printable area, top and bottom processing is performed for each page. The contents of the upper end processing and the lower end processing will be described later. Figure 7 (b) shows how the image is printed in the long mode. In the long mode, the image divided into N pages (N is an integer of 2 or more) is printed on the printing paper P without providing a margin between each page to print a continuous image. At the upper end of the first page where printing is started, the upper end processing is performed to expand the print area. Unlike the normal mode, the lower end processing is not performed. In addition, the top edge processing is not performed for the second and subsequent pages.

【0052】

The print mode can be specified by the user of the printing device. Printing in long mode is selected when a large format image is generated by the application program. It is CPU81 in computer 90 that executes the application program. The CPU 81 that executes the application program divides the image data into pages of a predetermined size and temporarily stores the image data together with the data such as the page size in the RAM 83.

【0053】

Figure 8 shows the structure of a series of data provided by the application program. As shown in the figure, a code indicating "data start" is added to the beginning of the series of data. After that, a code indicating the start of each page is attached, and then the image data of the page is provided. At the end of each page, a code indicating the end of the page is attached. A code indicating "end of data" is added to the end of the series of data. Since the data is provided by the application program in such a structure, it is not possible to determine whether or not the next page exists when the code indicating the end of the page is input. The code indicating the page start and page end will be collectively referred to as delimited data below.

【0054】

On the other hand, the CPU 81 also executes a printer driver program, which is a program for driving the printer 22 to execute printing. The printer driver program is started by a print instruction from the application program. Figure 9 shows the contents of the print data generation process, which is a part of the process of CPU81 when executing the printer driver program.

【0055】

When this process is started, the CPU 81 inputs the image data and the print mode (step S100). As shown in FIG. 8, the image data is divided into pages and expressed by the gradation values of R, G, and B. The CPU81 inputs delimited data as well as image data. The CPU 81 performs color conversion processing on the image data (step S105). The color conversion process is a process of correcting the color components of R, G, and B that specify image data to the color components of C, M, Y, and K that can be used by the printer 22 for each pixel. This process is performed using a color conversion table that gives C, M, Y, and K color components to the hues represented by the R, G, and B color systems. After that, the CPU 81 performs halftone processing of the color-converted image data (step S110). As a method of halftone processing, a well-known method such as a so-called error diffusion method or a dither method can be applied. Since the contents of the color conversion process and the halftone process are well known, detailed description thereof will be omitted.

【0056】

Next, the CPU 81 sets the sub-scanning amount of the printer 22, and executes a process for extracting the data to be transferred to the printer 22. In this embodiment, different sub-scanning amounts are stored in advance as a feed amount table depending on the print mode. Since the CPU81 refers to this table, it first determines whether or not the long mode is specified (step S115). When the long mode is not specified, that is, when the normal mode is specified, printing is executed by performing top edge processing and bottom edge processing for each page as shown in FIG. 7 (a). Therefore, the upper / lower end processing table in which the feed amount is set on the premise that the upper end processing and the lower end processing are performed is referred to (step S120). An example of the upper and lower end processing table is shown in FIG. As shown in the figure, the feed amount sequentially used for printing one page is stored as a one-dimensional table. Each number represents the feed amount in raster units. The data near the beginning of the table corresponds to the feed amount for the upper end processing, the data in the middle part corresponds to the standard feed for printing the image, and the data near the end corresponds to the feed amount for the lower end processing.

【0057】

On the other hand, when the long mode is specified, it is next determined whether or not the image data being processed is the data of the first page (step S125). As shown in FIG. 7 (b), on the first page of the long mode, the top processing table is referred to in order to perform the printing with the top processing applied (step S130). Since the top edge processing is not performed on the second and subsequent pages, the standard table is referenced (step S135). An example of these tables is shown in FIG. In the first page table, data corresponding to the feed amount for upper end processing is stored near the top, and standard feed data is stored after the middle. In this example, the feed of 3 rasters is performed 7 times as the upper end processing, and then the feed is shifted to the standard feed. In the standard table, only the data for standard feed is stored. This example means that the feed of "5 rasters-> 2 rasters-> 3 rasters-> 6 rasters" is executed periodically.

【0058】

The CPU 81 thus sets the sub-scanning amount according to the print mode and extracts the data to be transferred to the printer 22. That is, based on the feed amount of the sub-scan, it is determined which raster of the image data should be formed by each nozzle of the printer 22, and the data of the raster is extracted.

【0059】

Figure 11 shows this situation. The left side of FIG. 11 shows the position of the head in the sub-scanning direction in the first to third main scans. The circled numbers in the figure indicate the nozzles. For convenience of illustration, an example is shown in which four nozzles from Nozzle No. 1 to Nozzle No. 4 are provided with a nozzle pitch of 3 dots. In this example, a sub-scan equivalent to 4 rasters is executed for each main scan.

【0060】

On the right side of FIG. 11, the state of the pixels forming the image is shown. When the sub-scanning is performed with the above-mentioned feed amount, the image cannot be printed in the entire area because there is a portion where the raster can be formed only intermittently in the sub-scanning direction. In the first main scan, the image can be printed below the raster where Nozzle 3 is located. Therefore, in the first main scan, the CPU 81 extracts and supplies the data of the first raster of the image to the third nozzle, and extracts and supplies the data of the fourth raster from the beginning to the fourth nozzle. The raster number of the image data is attached to the right side of the figure for reference. In the second main scan, the second raster is supplied to the second nozzle, the fifth raster is supplied to the third nozzle, and the eighth raster is supplied to the fourth nozzle. In this way, the CPU 81 extracts the raster to be supplied to each nozzle according to the feed amount of the sub-scan.

【0061】

Here, in the present embodiment, in the long mode, since the sub-scanning is performed while maintaining a constant feed amount, the head may be located across a plurality of pages. For example, in the example of FIG. 11, in the third main scan, the first to third nozzles of the head are located on the first page, and the fourth nozzle is located on the second page. In such a case, wait for the input of the image data on the second page and extract the raster to be supplied to the Nozzle No. 4. As explained in FIG. 8, when the page end code is entered, the CPU 81 cannot determine whether the next page exists. Therefore, the CPU 81 further inputs data, and when the page start code is input, determines that the next page exists and waits for raster extraction until the image data is input. On the other hand, when the data end code is input, it means that the next page does not exist, so the raster is extracted without waiting for the input of further image data. In this case, only mask data, which means that dots are not formed, is supplied to some nozzles of the head.

【0062】

Next, the CPU 81 prepares for data transfer by rearranging the supply data to each nozzle extracted in this order in the order of transfer to the printer 22 (step S140). For example, when printing an image in both directions of reciprocating motion of the main scan, the arrangement of data is reversed according to the direction of the main scan. Further, in the case of performing so-called overlap recording in which each raster is formed by using two nozzles, the data of the odd-numbered pixels is supplied to one nozzle and the data of the even-numbered pixels is supplied to the other nozzle. Sort the data as follows. For nozzles that form only odd-numbered pixels, mask data is inserted into even-numbered pixels.

【0063】

The CPU 81 outputs the data set in this way to the printer 22 as print data together with the data of the feed amount of the sub-scan (step S145). These processes are repeated until all pages are finished (step S150). In FIG. 9, it is shown that all the image data of each page is input in step S100, but it is also possible to gradually input the image data while executing the color conversion process and the halftone process.

【0064】

The printer 22 prints in the mode shown in FIG. 7 based on the feed amount data and the print data output from the computer 90 by the above processing. FIG. 12 shows a flowchart of a dot formation control processing routine for realizing such printing. This process is a process executed by the CPU 41 provided in the control circuit 40 of the printer 22.

【0065】

When this process is started, the CPU 41 first inputs data (step S210). This data is print data that has been halftone-processed by the printer driver 96 and data that indicates the feed amount of each sub-scan. The CPU 41 stores the data input in this way in the RAM 42, transfers the raster data to be formed in the next main scan to the drive buffer 47, and sets the main scan data (step S220). Next, the CPU 41 drives the head to form dots while performing the main scan (step S230). When the formation of the main scan is completed, the sub scan is executed with the feed amount specified by the printer driver 96 (step S240). In the normal mode, when the delimiter data for each page is input, the sub-scanning is executed with the feed amount corresponding to the page break. In the long mode, a constant feed amount is maintained regardless of whether or not it is a page boundary even if delimited data is input. This process is repeated until printing is completed (step S250). When the printing of the image is completed, the back-feeding process of the printing paper is executed (step S260). The reverse printing process of printing paper means a process of returning the printing paper in the direction opposite to the sub-scanning direction in preparation for the next printing. The content of such processing will be described later.

【0066】

E. Dot formation: Fig. 13 shows the dot formation in this example. FIG. 13 is an explanatory diagram showing a state of dot formation by standard feed. Here, for convenience of illustration, a head equipped with eight nozzles at a 4-dot pitch is shown as an example. At this time, the standard feed is "5 rasters-> 2 rasters-> 3 rasters-> 6 rasters" as shown in the feed amount table of FIG. By periodically executing such a feed, it is possible to execute an overlap recording in which each raster is formed by two main scans. In the printable area in FIG. 13, each raster is formed by two nozzles. When printing is performed with such a feed from the beginning of printing, as shown in FIG. 13, a non-printable area of 23 rasters is generated before each raster can be formed by two main scans.

【0067】

In the long mode, the top page is processed to expand the print area. An example of top edge processing is shown in FIG. The nozzle pitch and the number of nozzles are the same as in the example of FIG. In this case, the feed of 3 rasters is performed 7 times as the upper end processing, and then the feed is shifted to the standard feed. When dots are formed by such feed, as shown in FIG. 14, the non-printable area until each raster can be formed by two main scans is equivalent to 18 rasters. That is, the print area is expanded by 5 rasters as compared with the case where the upper end processing is not performed. Various values can be set for these values according to the number of nozzles provided in the print head and the nozzle pitch. Of course, the upper end processing may not be performed.

【0068】

As explained earlier, in the normal mode, the bottom edge processing is performed for each page. Although the example of the lower end processing is omitted here, the printable area of the lower end portion of the page can be expanded by several rasters by printing with the feed amount shown in FIG.

【0069】

The back-feeding process of printing paper will be described with reference to FIG. As described above, the printer 22 prints with a standard feed amount even on the final page without performing bottom edge processing. FIG. 15 is an explanatory diagram showing the state of the final page when printing is performed while maintaining the standard feed amount in this way. The meanings of the symbols in the figure are the same as those in FIGS. 13 and 14.

【0070】

As shown in the figure, it is assumed that the area up to the raster where the first nozzle is located in the final main scan is the image print area. In FIG. 15, for convenience of illustration, the nozzle position in the conventional main scan is not sufficiently shown, but as is clear from FIG. 13, an image can be printed in the print area in FIG. 15 by repeating the standard feed. It turns out that.

【0071】

When the image of the final page has been printed, most of the head is located below the print area as shown in FIG. In some cases, as shown in FIG. 15, the lower end of the head may extend beyond the end of the last page and even enter the print area of the first page when printing is started next time. As shown in FIG. 13, when the first page is formed without performing the upper end processing, the Nozzle No. 5 is the nozzle that forms the first raster. Therefore, in this case, as a result of printing the final page while maintaining the standard feed, the excess feed shown in FIG. 15 occurs. The printer 22 returns the printing paper in the direction opposite to the sub-scanning direction by the amount corresponding to the overfeeding as the back-feeding process of the printing paper. In the reverse feed processing of the printing paper, the amount of excess feed may be calculated and returned by that amount, or the print paper may be completely removed from the feed mechanism and re-feeding may be performed.

【0072】

F. Effect and modification example: According to the above-mentioned printing apparatus, the image is printed while maintaining a constant feed amount even at the boundary portion in the long mode. Therefore, the same image quality can be maintained at the boundary portion and the other portion. That is, it is possible to avoid the occurrence of banding at the boundary portion of the page and improve the image quality. Moreover, since it is sufficient to maintain the feed amount at a constant cycle at all times, there is an advantage that the printing control process becomes very simple.

【0073】

Further, in the above-mentioned printing apparatus, the excess feed shown in FIG. 15 occurs by maintaining a constant feed amount even on the final page. Since the process of backfeeding the excess feed after the printing is completed, waste of printing paper can be eliminated. It should be noted that the back-feeding means is not an essential element in this embodiment, and if it can be overlooked that waste of printing paper occurs, this may be omitted to configure the printing apparatus.

【0074】

In the above-mentioned printing apparatus, printing in the long mode may be executed by ignoring the delimiter data. In this case, the image data provided by the application program divided into a plurality of pages can be treated as the data of a single page. When the long mode is specified, regardless of the size of the printing paper specified by the application program, printing is executed assuming a printing paper size of a sufficiently large size preset on the printer driver side. If this is done, long printing can be realized relatively easily. Specifically, in the flowchart shown in FIG. 9, a process of changing the size of the printing paper to a sufficiently large value may be performed between steps S115 and S120.

【0075】

Since the printing apparatus described above realizes the processing shown in FIG. 9 by a computer, it can also be implemented as a recording medium on which a program for realizing such processing is recorded. It is also possible to execute the print data generation process shown in FIG. 9 on the CPU 41 on the printer 22 side.

【0076】

Although various examples of the present invention have been described above, the present invention is not limited to these, and can be carried out in various forms without departing from the gist thereof. For example, some or all of the various control processes described in the above embodiment may be realized by hardware. In the above embodiment, the case where an auxiliary tool capable of supplying roll paper is attached to a printer that mainly uses so-called standard size paper is described as an example, but it can also be applied to a printer that mainly uses roll paper. Further, the print medium is not limited to roll paper as long as it is a medium capable of printing a large-format image.

[Simple explanation of drawings]

[Figure 1]

It is a schematic block diagram of the printing system to which the printing apparatus as an Example is applied.

[Figure 2]

It is explanatory drawing which shows the structure of software.

[Fig. 3]

It is a schematic block diagram of the printer as an Example.

[Fig. 4]

It is explanatory drawing which shows the arrangement of the nozzle in a head.

[Fig. 5]

It is explanatory drawing which shows the formation principle of a dot.

[Fig. 6]

It is explanatory drawing which shows the internal structure of the control device of a printer.

[Fig. 7]

It is explanatory drawing which shows the state of printing in each mode.

[Fig. 8]

It is explanatory drawing which shows the structure of image data.

[Fig. 9]

It is a flowchart of the print data generation processing routine.

[Fig. 10]

It is explanatory drawing which shows the content of the feed amount table.

[Fig. 11]

It is explanatory drawing which shows the relationship between the data provided to a nozzle and image data.

[Fig. 12]

It is a flowchart of a dot formation control processing routine.

[Fig. 13]

It is explanatory drawing which shows the state of the dot recording when the upper end processing is not performed.

[Fig. 14]

It is explanatory drawing which shows the example of the upper end processing.

[Fig. 15]

It is explanatory drawing which shows the positional relationship of a head and a printing paper on the last page.

[Fig. 16]

It is explanatory drawing which shows the state of the dot recording by the interlace method.

[Fig. 17]

It is explanatory drawing which shows the state of printing of the long mode as a prior art.

[Fig. 18]

It is explanatory drawing which shows the example of the lower end processing in the conventional long mode printing.

[Fig. 19]

It is explanatory drawing which shows the example of the upper end processing in the conventional long mode printing.

[Explanation of symbols]

14 ... keyboard 16 ... Hard disk 18 ... Modem 22 ... Color printer 23 ... motor 24 ... Carriage motor 26 ... Platen 28 ... Printhead 31 ... Carriage 32 ... Operation panel 34 ... Sliding shaft 36 ... drive belt 38 ... pulley 39 ... Position detection sensor 40 ... control circuit 45 ... Input / output section 46 ... timer 47 ... Drive buffer 48 ... Bus 51 ... transmitter 55 ... Distribution output device 61 ~ 64 ... Ink ejection head 68 ... Ink passage 71 ... Cartridge 72 ... Color ink cartridge 80 ... Bus 81 ... CPU 82 ... ROM 83 ... RAM 84 ... Input interface 85 ... Output interface 87 ... disk controller 88 ... Serial I / O interface 90 ... computer 91 ... Video driver 95 ... application program 97 ... spooler 98 ... Despula 96 ... Printer driver 99 ... Color conversion module 100 ... halftone module 101 ... Feed amount setting unit 102 ... Data output section 201 ... Input section 202 ... buffer 203 ... Main scanning unit 204 ... Sub-scanning unit