Printing up to end part of print sheet without contaminating platen

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention relates to a technique for recording dots on the surface of a recording medium using a dot recording head, and more particularly to a technique for printing to the edge of printing paper without soiling the platen.

【0002】

[Conventional technology]

In recent years, a printer that ejects ink from a nozzle of a print head has become widespread as an output device of a computer. FIG. 30 is a side view showing the periphery of the print head of a conventional printer. The printing paper P is supported on the platen 26o so as to face the head 28o. Then, the printing paper P is fed in the direction of arrow A by the upstream side paper feed rollers 25p, 25q arranged upstream of the platen 26o and the downstream side paper feed rollers 25r, 25s arranged downstream of the platen 26. .. When the ink is ejected from the head, dots are sequentially recorded on the printing paper P and an image is printed.

【0003】

[Problems to be Solved by the Invention]

When printing an image to the edge of the printing paper in a printer as described above, it is necessary to arrange the printing paper so that the edge of the printing paper is located below the print head, that is, on the platen, and eject ink droplets from the print head. There is. However, in such printing, the ink droplets may deviate from the edge of the printing paper that should have landed and land on the platen due to an error in the feeding of the printing paper or a deviation in the landing position of the ink droplets. .. In such a case, the ink that has landed on the platen stains the printing paper that subsequently passes over the platen.

【0004】

The present invention has been made to solve the above-mentioned problems in the prior art, and an object of the present invention is to provide a technique for printing to the edge of a printing paper without causing ink droplets to land on the platen.

【0005】

[Means for solving problems and their actions / effects]

In order to solve at least a part of the above-mentioned problems, the present invention provides a dot recording device that records dots on the surface of a printing medium using a dot recording head provided with a plurality of dot forming elements for ejecting ink droplets. Perform a predetermined process as a target. The dot recording device is provided extending in the direction of the main scanning so as to face the dot forming element in at least a part of the main scanning path, supports the print medium so as to face the dot recording head, and has a plurality of dots. The platen is provided with a groove extending in the direction of the main scan at a position facing the dot forming element located at at least one end of the forming elements at both ends in the direction of the sub-scan.

【0006】

Printing (dot recording) performed in such a printing apparatus drives at least one of a dot recording head and a printing medium to perform a main scan while driving at least a part of a plurality of dot forming elements. This is a dot recording in which dots are formed and a print medium is driven in a direction intersecting the direction of the main scan between main scans to perform a sub scan. At that time, when dots are recorded in the first recording mode in the vicinity of the edge of the print medium, the print medium is supported by the platen, and the upper end or the lower end of the print medium is above the opening of the groove. Edge printing is performed in which ink droplets are ejected from at least a part of a dot forming element located at a position facing the groove to form dots on a printing medium. Then, in the intermediate portion of the print medium, dots are recorded in the second recording mode in which the maximum sub-scan feed amount is larger than the maximum sub-scan feed amount in the first recording mode.

【0007】

In such an embodiment, the dot-forming element located at a position facing the groove can be used to print without a margin up to the edge of the printing paper without causing ink droplets to land on the platen.

【0008】

Further, when performing edge printing, it is preferable not to eject ink droplets from dot forming elements other than the dot forming element located at a position facing the groove portion. In such an aspect, in printing at the upper end of the print medium, when the feed amount of the sub-scanning of the print medium up to that point is insufficient and the upper end does not reach the groove, that is, the upper end of the print medium is platen. The platen is not contaminated by ink droplets even when it is located above and a part of the platen faces the dot recording head directly. The same applies to the case where the feed amount of the sub-scanning of the print medium is excessive in printing at the lower end of the print medium and the lower end of the print medium passes over the groove.

【0009】

When the groove is provided at a position facing at least the dot-forming element located at the downstream end in the sub-scanning direction among the plurality of dot-forming elements, when the upper end of the print medium is above the groove opening, It is preferable to perform edge printing. In such an aspect, an image can be recorded on the upper end of the print medium without a margin.

【0010】

Further, when the groove portion is provided at a position facing at least the dot forming element located at the upstream end in the sub-scanning direction among the plurality of dot forming elements, when the lower end of the print medium is above the opening of the groove portion. It is preferable to perform edge printing. In such an aspect, the image can be recorded without a margin at the lower end of the print medium.

【0011】

A sub-scanning drive unit that performs sub-scanning in the printing apparatus is provided on the upstream side in the sub-scanning direction with respect to the dot recording head, and is an upstream sub-scanning drive that holds the printing medium and drives the printing medium. In the embodiment including the unit and the downstream sub-scanning drive unit provided on the downstream side in the sub-scanning direction with respect to the dot recording head to hold the print medium and drive the print medium, as described above. Dot recording has the following advantages.

【0012】

In the printing apparatus as described above, when printing the end portion of the printing medium, the sub-scanning must be performed by only one of the upstream sub-scanning drive unit and the downstream sub-scanning drive unit. In such a printing apparatus, if the above-mentioned printing is performed, it is possible to shorten the distance for performing printing by performing sub-scanning with only one of the upstream sub-scanning drive unit and the downstream sub-scanning drive unit.

【0013】

The sub-scanning feed executed in the first recording mode is preferably a sub-scanning feed in units of 1 dot. In this way, the end portion of the print medium can be recorded by the nozzle near the end portion in the sub-scanning direction in the dot recording head.

【0014】

In the case of printing as described above, an image to be recorded is generated on the print medium beyond the edge where edge printing is performed to the outside of the print medium, and the image is generated. It is preferable to form dots based on the data. By doing so, even if there is a positioning error of the print medium, printing can be performed on the print medium of the portion protruding from the assumed position based on the image set on the outside of the print medium.

【0015】

Further, in the image data, the dimension of the portion of the image beyond the edge where the edge printing of the print medium is performed is preferably set to be less than the width of the groove. By doing so, even when the ink droplets for recording the portion set beyond the edge where the edge printing of the print medium is performed do not land on the print medium, those ink droplets The print medium can be positioned with respect to the dot recording head so as to land in the groove.

【0016】

The present invention can be realized in various aspects as shown below. (1) Dot recording method, print control method, print method. (2) Dot recording device, print control device, printing device. (3) A computer program to realize the above devices and methods. (4) A recording medium on which a computer program for realizing the above devices and methods is recorded. (5) A data signal embodied in a carrier wave including a computer program for realizing the above devices and methods.

【0017】

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described in the following order based on examples. A. Outline of the embodiment: B. First Example: C. Second Example: D. Third Example: E. Aspects with lateral grooves: F. Modification example: [0018]

A. Outline of Embodiment: FIG. 1 is a side view showing a structure around a print head of an inkjet printer according to an embodiment of the present invention. In FIG. 1, the printing paper P is held and fed by the upstream paper feed rollers 25a and 25b (secondary scanning feed), and its front end Pf passes over the upstream groove portion 26f and the platen 26. It reaches above the opening of the downstream groove 26r. At this time, ink droplets Ip are ejected from the print head 28 to start printing. Since printing is started when the front edge Pf of the printing paper P is behind the nozzle # 1, even if there is a slight paper feed error, the image is printed to the edge without creating a margin at the front edge Pf of the printing paper P. can do. The ink droplets that have not landed on the printing paper P are absorbed by the absorbing member 27r.

【0019】

When printing near the front edge Pf of the printing paper P, it is preferable to repeat printing with a minute sub-scanning feed having a feed amount of 1 dot. By doing so, it becomes easy to print the front end portion of the printing paper on the downstream groove portion 26r.

【0020】

FIG. 2 shows a state of printing at the lower end Pr of the printing paper P. In FIG. 2, in the final stage of printing, the printing paper P is held and fed only by the downstream side paper feed rollers 25c and 25d, and the rear end Pr reaches above the opening of the downstream side groove portion 26r. At this time, ink droplets are ejected from the print head 28 to print the rear end portion of the printing paper. Since printing is performed when the rear end Pr of the printing paper P is in front of nozzle # 8, even if there is a slight paper feed error, the image can be printed to the edge without creating a margin at the rear end Pr of the printing paper. Can be printed. The ink droplets that have not landed on the printing paper P are absorbed by the absorbing member 27f.

【0021】

Even when printing near the rear edge Pr of the printing paper, it is preferable to repeat the minute sub-scanning feed for printing. By doing so, it becomes easy to print the rear end portion of the printing paper on the upstream groove portion 26f.

【0022】

B. First Example: (1) Device Configuration: FIG. 3 is a block diagram showing a configuration of an image processing device and a printing device as examples of the present invention. As shown, the scanner 12 and the printer 22 are connected to the computer 90. When a predetermined program is loaded and executed on the computer 90, it functions as an image processing device and also functions as a printing device together with the printer 22. The computer 90 includes the following parts connected to each other by a bus 80, centering on a CPU 81 that executes various arithmetic processes for controlling operations related to image processing according to a program. The ROM 82 stores various programs and data necessary for executing various arithmetic processes on the CPU 81 in advance, and the RAM 83 temporarily stores various programs and data necessary for executing various arithmetic processes on the CPU 81. A memory that is read and written. The input interface 84 controls the input of signals from the scanner 12 and the keyboard 14, 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, flexible drive 15, or CD-ROM 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.

【0023】

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 by connecting to a specific server SV, it is possible to download the program required for image processing to the hard disk 16. It is also possible to load the necessary programs on a flexible disk FD or CD-ROM and have the computer 90 execute them.

【0024】

FIG. 4 is a block diagram showing a software configuration of the printing apparatus. 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 image data D for transfer to the printer 22 via these drivers. The application program 95 that retouches the image reads the image from the scanner 12, and displays the image on the CRT 21 via the video driver 91 while performing predetermined processing on the image. The data ORG supplied from the scanner 12 is a primary color image data ORG that is read from a color document and is composed of three color components of red (R), green (G), and blue (B).

【0025】

When the application program 95 issues a print instruction, the printer driver 96 of the computer 90 receives the image data from the application program 95, and the printer 22 can process the signals (here, cyan, magenta, light cyan, light magenta, etc.). It is converted to a multi-valued signal for each color of yellow and black). In the example shown in FIG. 4, the resolution conversion module 97, the color correction module 98, the halftone module 99, and the rasterizer 100 are provided inside the printer driver 96. The color correction table LUT and the dot formation pattern table DT are also stored. The application program 95 corresponds to the "image data generation unit" in the claims.

【0026】

The resolution conversion module 97 plays a role of converting the resolution of the color image data handled by the application program 95, that is, the number of pixels per unit length into a resolution that can be handled by the printer driver 96. Since the image data whose resolution has been converted in this way is still image information consisting of three RGB colors, the color correction module 98 refers to the color correction table LUT, and the cyan (C) used by the printer 22 for each pixel. Converts to magenta (M), light cyan (LC), light magenta (LM), yellow (Y), and black (K) color data.

【0027】

The color-corrected data has a gradation value with a width of, for example, 256 gradations. The halftone module 99 executes halftone processing for expressing this gradation value in the printer 22 by forming the dots in a dispersed manner. The halftone module 99 sets the dot formation pattern of each ink dot according to the gradation value of the image data by referring to the dot formation pattern table DT, and then executes the halftone processing. The image data processed in this way is sorted by the rasterizer 100 in the order of data to be transferred to the printer 22, and is output as the final print data PD. The print data PD includes raster data indicating the recording state of dots at each main scan and data indicating the sub-scan feed amount. In this embodiment, the printer 22 only plays a role of forming ink dots according to the print data PD and does not perform image processing, but of course, these processes may be performed by the printer 22.

【0028】

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 ink dots, and a control circuit 40 that controls the exchange of signals with the paper feed motor 23, the carriage motor 24, the print head 28, and the operation panel 32. ing.

【0029】

The mechanism for reciprocating the carriage 31 in the axial direction of the platen 26 is erected in parallel with the axis of the platen 26, and is an endless drive belt between the sliding shaft 34 that 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.

【0030】

The carriage 31 contains a cartridge 71 for black ink (K) and six color inks of cyan (C), light cyan (LC), magenta (M), light magenta (LM), and yellow (Y). Cartridge 72 can be mounted. A total of six ink ejection heads 61 to 66 are formed on the print head 28 at the bottom of the carriage 31, and an introduction tube 67 for guiding ink from the ink tank to the heads for each color is formed at the bottom of the carriage 31. It is erected. When the black (K) ink cartridge 71 and the color ink cartridge 72 are mounted on the carriage 31 from above, the introduction tube 67 is inserted into the connection holes provided in each cartridge, and the ejection heads 61 to 66 are inserted from each ink cartridge. Ink can be supplied to the carriage.

【0031】

The heads 61 to 66 of each color provided in the lower part of the carriage 31 are provided with 48 nozzles Nz for each color, and each nozzle is a piezo which is one of the electrodistortion elements and has excellent responsiveness. The element PE is arranged. The piezo element PE is installed at a position in contact with the ink passage that guides the ink to 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. In this embodiment, by applying a voltage having a predetermined time width between the electrodes provided at both ends of the piezo element PE, the piezo element PE is extended by the voltage application time and one side wall of the ink passage is deformed. As a result, the ink passage 68 product 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.

【0032】

FIG. 6 is an explanatory diagram showing the arrangement of the inkjet nozzles Nz in the ink ejection heads 61 to 66. The arrangement of these nozzles is from 6 sets of nozzle arrays that eject ink for each color of black (K), cyan (C), light cyan (LC), magenta (M), light magenta (LM), and yellow (Y). Each of the 48 nozzles is arranged in a row with a constant nozzle pitch k. The "nozzle pitch" is a value indicating how many rasters (that is, how many pixels) the interval of the nozzles arranged on the print head in the sub-scanning direction is. For example, the pitch k of the nozzles arranged at intervals of 3 rasters is 4.

【0033】

FIG. 7 is a plan view showing the periphery of the platen 26. The platen 26 is provided in the direction of the main scan longer than the maximum width of the printing paper P that can be used by the printer 22. Upstream paper feed rollers 25a and 25b are provided upstream of the platen 26. The upstream side paper feed roller 25a is one drive roller, while the upstream side paper feed roller 25b is a plurality of freely rotating small rollers. Further, downstream side paper feed rollers 25c and 25d are provided downstream of the platen. The downstream side paper feed roller 25c is a plurality of rollers provided on the drive shaft, and the downstream side paper feed roller 25d is a plurality of freely rotating small rollers. A groove is provided on the outer peripheral surface of the downstream paper feed roller 25d in parallel with the rotation axis direction. That is, the downstream side paper feed roller 25d has teeth (the portion between the grooves) radially on the outer peripheral surface, and looks like a gear when viewed from the direction of the rotation axis. This downstream paper feed roller 25d is commonly called a "jagged roller" and plays a role of pressing the printing paper P onto the platen 26. The downstream side paper feed roller 25c and the upstream side paper feed roller 25a rotate synchronously so that the outer peripheral speeds are equal.

【0034】

The print head 28 reciprocates in the main scan on the platen 26 sandwiched between the upstream paper feed rollers 25a and 25b and the downstream paper feed rollers 25c and 25d. The printing paper P is held by the upstream paper feed rollers 25a and 25b and the downstream paper feed rollers 25c and 25d, and the portion between them is supported by the upper surface of the platen 26 so as to face the nozzle row of the print head 28. Then, the upstream side paper feed rollers 25a and 25b and the downstream side paper feed rollers 25c and 25d perform sub-scanning feed, and the images are sequentially recorded by the ink discharged from the nozzle of the print head 28. The upstream paper feed rollers 25a and 25b are the "upstream sub-scanning drive unit" in the claims, and the downstream paper feed rollers 25c and 25d are the "downstream sub-scanning drive" in the claims. Department ".

【0035】

Further, the platen 26 is provided with an upstream groove portion 26f and a downstream groove portion 26r, respectively, on the upstream side and the downstream side in the sub-scanning direction. The upstream groove 26f and the downstream groove 26r are provided along the main scanning direction, respectively, longer than the maximum width of the printing paper P that can be used by the printer 22. Further, absorbing members 27f and 27r for receiving and absorbing ink droplets Ip are arranged at the bottoms of the upstream groove portion 26f and the downstream groove portion 26r, respectively. The downstream groove portion 26r is provided at a position facing a part of the nozzle group Nr on the downstream side including the most downstream nozzle among the nozzles Nz on the print head 28 (nozzles in the portion indicated by the diagonal line in FIG. 7). There is. The upstream groove portion 26f is provided at a position facing a part of the nozzle group Nf (not shown in FIG. 7) on the upstream side including the most upstream nozzle among the nozzles on the print head 28. The printing paper P passes over the openings of the upstream groove 26f and the downstream groove 26r when the sub-scanning feed is performed by the upstream paper feed rollers 25a and 25b and the downstream paper feed rollers 25c and 25d. I will go.

【0036】

Next, the internal configuration of the control circuit 40 (see FIG. 5) of the printer 22 will be described. Inside the control circuit 40, in addition to the CPU 41, PROM 42, and RAM 43, a PC interface 45 that exchanges data with the computer 90 and a drive that outputs ink dot ON / OFF signals to the ink ejection heads 61 to 66. A buffer 44 or the like is provided, and these elements and circuits are connected to each other by a bus. The control circuit 40 receives the dot data processed by the computer 90, temporarily stores the dot data in the RAM 43, and outputs the dot data to the drive buffer 44 at a predetermined timing.

【0037】

The printer 22 having the hardware configuration described above reciprocates the carriage 31 by the carriage motor 24 while transporting the paper P by the paper feed motor 23, and at the same time drives the piezo elements of each nozzle unit of the print head 28. , Each color ink droplet Ip is ejected to form ink dots to form a multicolored image on the paper P.

【0038】

In the printer of this embodiment, in order to print the upper end Pf of the printing paper P on the downstream groove 26r and the lower end Pr on the upstream groove 26f, in the vicinity of the upper end and the lower end of the printing paper, A printing process different from that of the middle part of the printing paper is performed. In this specification, the printing process in the middle part of the printing paper is called "intermediate processing", the printing process near the upper end of the printing paper is "upper end processing", and the printing process near the lower end of the printing paper is "lower end processing". Called. Further, when the upper end processing and the lower end processing are collectively called, it is called "upper and lower end processing".

【0039】

Further, the width W of the upstream groove portion 26f and the downstream groove portion 26r in the sub-scanning direction can be determined by the following equation.

【0040】

W = p × n + α [0041]

Here, p is the feed amount [inch] of the sub-scan feed in the upper and lower end processing. n is the number of sub-scan feeds performed in each of the upper end processing and the lower end processing. α is the error of the sub-scanning feed assumed in each of the upper end processing and the lower end processing. It is preferable that the value of α in the lower end treatment (upstream groove 26f) is set larger than the value of α in the upper end treatment (downstream groove 26r). If the width of the groove portion of the platen is determined by the above formula, it is possible to provide the groove portion having a width sufficient to receive the ink droplets ejected from the nozzle during the upper and lower end processing.

【0042】

(2) Sub-scan feed: (i) Top Processing of First Example: FIG. 8 is an explanatory diagram showing how each raster is recorded by which nozzle in the vicinity of the top edge (tip) of the printing paper. Here, for the sake of simplicity, only one row of nozzle rows will be used. And it is assumed that one row of nozzles has eight nozzles. During the main scan, each nozzle is responsible for recording one raster. Here, the "raster" is a row of pixels arranged in the main scanning direction. The "pixel" is a grid-shaped grid virtually defined on the print medium in order to define the position where the ink droplets are landed and the dots are recorded. Here, it is assumed that the nozzles are arranged at intervals of 3 rasters.

【0043】

In FIG. 8, one row of squares arranged vertically represents the print head 28. The numbers 1 to 8 in each square indicate the nozzle number. In the specification, "#" is added to these numbers to indicate each nozzle. In FIG. 8, the print heads 28, which are relatively fed in the sub-scanning direction with time, are shown shifted in order from left to right. As shown in FIG. 8, in the upper end processing, the sub-scan feed for each dot is repeated 7 times. This upper end processing is printing in the "first recording mode" in the claims. The "dot", which is a unit of the sub-scan feed amount, means a pitch of one dot corresponding to the print resolution in the sub-scan direction, which is also equal to the raster pitch.

【0044】

After that, the process shifts to intermediate processing, and the feeding of 5 dots, 2 dots, 3 dots, and 6 dots is repeated in that order. This intermediate process is printing in the "second recording mode" as defined in the claims. A method of performing sub-scanning by combining different feed amounts in this way is called "irregular feed". When the sub-scan feed as described above is performed, each raster is recorded by two nozzles, except for some rasters. That is, in this embodiment, each raster is printed with two nozzles. For example, in FIG. 8, the fifth raster from the top is recorded by nozzle # 2 and nozzle # 1. At this time, the nozzle # 2 records, for example, the pixels of even-numbered addresses, and the nozzle # 1 records the pixels of odd-numbered addresses. The ninth raster from the top is recorded by nozzle # 3 and nozzle # 2. In this way, the method of printing by sharing the pixels in one raster with a plurality of nozzles is called "overlap printing". In overlap printing, one raster is recorded with dots by a plurality of nozzles passing over the raster in a plurality of main scans in which the positions of the printing paper in the sub-scanning direction with respect to the print head are different from each other.

【0045】

On the other hand, in FIG. 8, the four rasters from the top row pass through the nozzle # 1 only once in the main scan during printing. Therefore, for these rasters, the pixels cannot be shared and printed by the two nozzles. Therefore, in this embodiment, it is assumed that these four rasters are not used for recording an image. That is, the raster that can be used for recording an image in this embodiment is the fifth or later raster from the upstream end in the sub-scanning direction among the rasters on which the nozzle on the print head 28 can record dots. The area of the raster that can be used to record this image is called the "printable area". Further, the raster area that is not used for image recording is called a "non-printable area". In FIG. 8, the rasters on which the nozzles on the print head 28 can record dots are numbered in order from the top on the left side of the figure. Hereinafter, the same applies to the drawings for explaining the recording of dots in the upper end processing. The nozzle surrounded by a thick frame in the figure is a nozzle that records dots on the raster.

【0046】

Further, in FIG. 8, the 13th and 15th rasters from the top pass through three nozzles in the main scan during printing. For such rasters through which three or more nozzles pass in printing, only two of them shall record dots. It is preferable to record those rasters with nozzles that pass over the rasters after shifting to intermediate processing as much as possible. In the intermediate processing, irregular feed is performed, and the combination of nozzles passing on adjacent rasters is different. Therefore, the print result is higher quality than the upper end processing in which regular feed is performed one dot at a time. This is because it can be expected to become.

【0047】

In this embodiment, the image is recorded without a margin up to the upper edge of the printing paper. As described above, in the present embodiment, among the rasters on which the nozzles on the print head 28 can record dots, the fifth and subsequent rasters (printable area) from the upstream end in the sub-scanning direction are used for the image. Can be recorded. Therefore, theoretically, if the printing paper is arranged with respect to the print head 28 and the dot recording is started so that the fifth raster from the edge is located at the position just above the upper edge of the printing paper, Images can be recorded up to the top edge of the printing paper. However, there may be an error in the feed amount during the sub-scan feed. In addition, the ink droplet ejection direction may shift due to a manufacturing error of the print head or the like. For that reason, it is preferable that no margin is generated at the upper end of the printing paper even when the landing position of the ink droplet on the printing paper is displaced. Therefore, in this embodiment, the image data D used for printing is set from the fifth raster from the upstream end in the sub-scanning direction among the rasters on which the nozzle on the print head 28 can record dots, while printing. Printing is started from the state where the upper end of the paper P is at the position of the seventh raster from the upstream edge in the sub-scanning direction. Therefore, as shown in FIG. 8, the assumed position of the upper end of the printing paper for each raster at the start of printing is the position of the seventh raster from the upstream end in the sub-scanning direction.

【0048】

FIG. 9 is a plan view showing the relationship between the image data D and the printing paper P. As described above, in this embodiment, the image data D is set beyond the upper end Pf of the printing paper P to the outside of the printing paper P. Also, for the same reason, the image data D is set on the lower end side beyond the lower end Pr of the printing paper P to the outside of the printing paper P. Therefore, in this embodiment, the relationship between the size of the image data D and the printing paper P and the arrangement of the image data D and the printing paper P at the time of printing is shown in FIG. In this embodiment, the width of the portion of the image data D set beyond the upper end Pf of the printing paper P to the outside of the printing paper P is 2 rasters. Further, the width of the portion of the image data D set beyond the lower end Pr of the printing paper P to the outside of the printing paper P is also 2 rasters. In this specification, when the end of the printing paper P is referred to corresponding to the top and bottom of the image data to be recorded on the printing paper P, the terms "upper end (part)" and "lower end (part)" are used. When calling the edge of the printing paper P corresponding to the traveling direction of the sub-scanning feed of the printing paper P on the printer 22, the terms "front edge (part)" and "rear edge (part)" are used. In the present specification, in the printing paper P, the "upper end (part)" corresponds to the "front end (part)" and the "lower end (part)" corresponds to the "rear end (part)".

【0049】

FIG. 10 is a side view showing the relationship between the print head 28 and the printing paper P at the start of printing. Here, the platen 26 is provided in the range R26 from the position 2 rasters behind the # 2 nozzle of the print head 28 to the position 2 rasters before the # 7 nozzle. To do. Therefore, even if the ink droplets Ip are ejected from each nozzle without the printing paper, the ink droplets from the nozzles # 1, # 2, # 7, and # 8 do not land on the platen 26.

【0050】

In FIG. 7, the nozzle group Nr of the portion indicated by the diagonal line of the print head 28 is the portion where the nozzles of # 1 and # 2 are located. A downstream groove portion 26r is provided below the portion through which those nozzles pass during the main scanning, and when the upper end Pf of the printing paper P is located at the position indicated by the alternate long and short dash line on the downstream groove portion 26r. Printing starts.

【0051】

As described above, at the start of printing, the upper end Pf of the printing paper P is at the position of the seventh raster from the upstream end in the sub-scanning direction among the rasters on which the nozzles on the print head 28 can record dots. That is, to explain using FIG. 10, the upper end of the printing paper P is located 6 rasters behind the nozzle # 1. In FIG. 10, the position of the raster assumed on the image data is indicated by a broken line. Therefore, if printing is started from this state, the top raster of the printable area (the fifth raster from the top in Fig. 8) should be recorded by nozzle # 2, but # There is no printing paper P below the nozzle of 2. Therefore, if the printing paper P is accurately fed by the upstream paper feed rollers 25a and 25b, the ink droplet Ip ejected from the nozzle # 2 will fall directly into the downstream groove 26r. In addition, as shown in FIG. 8, the raster at the top of this printable area is also recorded by the # 1 nozzle after four 1-dot feeds. However, similarly, at the stage where the 1-dot feed is performed four times, there is no printing paper P under the nozzle of # 1. Therefore, the ink droplet Ip ejected from the nozzle # 1 at that time also falls into the downstream groove portion 26r as it is. The same can be said for the case of recording the second raster from the top of the printable area (the sixth raster from the top in FIG. 8).

【0052】

However, if for some reason the printing paper P is fed more than the original feed amount, the upper end of the printing paper P is the second raster from the top of the printable area or the top of the printable area. It may come to the position of the raster of. In this embodiment, even in such a case, since the nozzles # 1 and # 2 eject ink droplets Ip to those rasters, an image can be recorded on the upper end of the printing paper P, and the margins can be recorded. Will not be created. That is, even if the printing paper P is fed more than the original feed amount, as shown by the alternate long and short dash line in FIG. 10, if the extra feed amount is 2 rasters or less, the printing paper P is fed. There is no margin at the top of the.

【0053】

On the contrary, it is conceivable that the printing paper P is fed less than the original feed amount for some reason. In such a case, the printing paper is not at the position where the printing paper should be, and the ink droplet Ip will land on the structure below. However, as shown in FIG. 8, in this embodiment, two rasters from the assumed upper end position of the paper are recorded by the nozzles # 1 and # 2. A downstream groove 26r is provided below these nozzles, and even if the ink droplet Ip does not land on the printing paper P, the ink droplet Ip falls on the downstream groove 26r and the absorbing member 27r. Will be absorbed by. Therefore, the ink droplet Ip does not land on the upper surface of the platen 26 and later stain the printing paper. That is, in this embodiment, even if the upper end Pf of the printing paper P is behind the assumed upper end position at the start of printing, if the amount of deviation from the assumed upper end position is 2 rasters or less, the ink droplet Ip Will not land on the upper surface of the platen 26 and later stain the printing paper P.

【0054】

It is desirable that the printing paper P is held by two sets of rollers, the upstream side paper feed rollers 25a and 25b and the downstream side paper feed rollers 25c and 25d, and is fed by sub-scanning. This is because the sub-scanning feed can be performed more accurately than when the sub-scanning feed is held by only one roller. However, when printing the upper end Pf of the printing paper, the printing paper P is held only by the upstream paper feed rollers 25a and 25b, and is subjected to the sub-scanning feed. In this embodiment, printing is started in a state where the upper end Pf of the printing paper is located at the position of the seventh raster from the upstream end in the sub-scanning direction among the rasters on which the nozzle on the print head 28 can record dots. (See Figures 8 and 10). Therefore, as shown in FIG. 10, from that position until the upper end Pf of the printing paper is held by the downstream side paper feed rollers 25c and 25d, that is, while the printing paper is fed by the distance of L31, the upstream side paper. Sub-scan feed is performed only by the feed rollers 25a and 25b, and printing is executed. In this embodiment, the sub-scanning feed is performed only by the upstream paper feed rollers 25a and 25b, and the section in which printing is executed is relatively short, so that the print result becomes high quality. In addition to the above-described embodiment, the above-mentioned effect can be obtained by printing the vicinity of the upper end Pf of the printing paper with a nozzle near the downstream end in the sub-scanning direction. It is particularly effective when the feed accuracy of the upstream sub-scanning drive unit (upstream side paper feed rollers 25a, 25b) is relatively low.

【0055】

Further, when printing the upper end portion, the printing paper P is supported by two places, the upstream side paper feed rollers 25a and 25b and the upper surface of the platen 26. Therefore, the upper end portion of the printing paper P is relatively less likely to bend downward on the downstream groove portion 26r. Therefore, it is unlikely that the quality of the print result at the upper end portion will deteriorate due to the bending of the printing paper.

【0056】

(ii) Top Feed of Comparative Example: FIG. 11 is a side view showing the relationship between the print head 28 and the printing paper P at the start of printing in the comparative example. As shown in FIG. 11, even if the upper end portion of the printing paper P is printed on the upstream groove portion 26f, the ink droplets that have not landed on the printing paper P do not land on the upper surface of the platen 26. However, in this comparative example, the distance L32 at which the printing paper is fed from the start of printing on the upper end portion of the printing paper until the upper end of the printing paper is held by the downstream paper feed rollers 25c and 25d (see FIG. 11). ) Is longer than that of the example (L31 in FIG. 8). That is, the sub-scanning feed is performed only by the upstream paper feed rollers 25a and 25b, and the section in which printing is executed is relatively long. Therefore, the quality of the print result is lower than that of the examples.

【0057】

Further, when printing the upper end portion, the printing paper P is held only by the upstream side paper feed rollers 25a and 25b. Therefore, the upper end portion of the printing paper P tends to bend downward on the upstream groove portion 26f. Therefore, when printing the upper end portion, there is a relatively high possibility that the quality of the print result is deteriorated.

【0058】

(iii) Lower end processing of the first embodiment: FIG. 12 is an explanatory diagram showing how each raster is recorded by which nozzle in the lower end processing. FIG. 12 shows from the place where the n + 1th sub-scan feed is performed to the place where the last n + 17th sub-scan feed is performed. In this embodiment, as shown in FIG. 12, in the intermediate processing, the feeding of 5 dots, 2 dots, 3 dots, and 6 dots is repeated in that order in the sub-scan feed up to the n + 8th time, and then the last in the lower end processing. 9 times, that is, from the n + 9th time to the n + 17th time, the sub-scan feed is performed one dot at a time. As a result, each raster along the main scanning direction is recorded with two nozzles, except for some. In FIG. 12, the rasters on which the nozzles on the print head 28 can record dots are numbered in order from the bottom on the right side of the figure. Hereinafter, the same applies to the drawings for explaining the recording of dots in the lower end processing.

【0059】

In FIG. 12, the four rasters from the bottom are only passed through the nozzle # 8 once in printing. Then, the fifth or more rasters from the bottom can be recorded by two or more nozzles. Therefore, the printable area at the lower end of the printing paper is the area of the fifth or more rasters from the bottom.

【0060】

Further, in FIG. 12, the ninth and tenth rasters from the bottom pass through three or more nozzles in the main scan during printing. For such a raster through which three or more nozzles pass in printing, it is preferable to record with the nozzles passing over the raster in the intermediate processing as much as possible. This is because it can be expected that the print result will have higher image quality than the lower end processing in which the regular feed is performed one dot at a time.

【0061】

In this embodiment, as in the case of the upper end, the image is recorded at the lower end without any margin. As described above, in the present embodiment, among the rasters on which the nozzles on the print head 28 can record dots, the fifth or higher raster (printable area) from the downstream end in the sub-scanning direction is used for the image. Can be recorded. However, in consideration of a case where an error occurs in the feed amount during the sub-scan feed, recording is performed on the printing paper from the seventh raster from the end downstream in the sub-scan direction. That is, with the lower end of the printing paper at the position of the 7th raster from the upstream edge in the sub-scanning direction, ink droplets Ip are also ejected to the 5th and 6th rasters, and the final main printing is performed. Scan. Therefore, as shown in FIG. 12, the assumed position of the lower end of the printing paper for each raster at the end of printing is the position of the seventh raster from the downstream end in the sub-scanning direction.

【0062】

FIG. 13 is a plan view showing the relationship between the upstream groove portion 26f and the printing paper P when printing the lower end portion Pr of the printing paper P. In FIG. 13, the nozzle group Nf of the portion indicated by the diagonal line of the print head 28 is the portion where the nozzles of # 7 and # 8 are located. An upstream groove portion 26f is provided below the portion through which those nozzles pass during main scanning, and when the lower end Pr of the printing paper P is located at the position indicated by the alternate long and short dash line on the upstream groove portion 26f. Finish printing.

【0063】

FIG. 14 is a side view showing the relationship between the print head 28 and the printing paper P when printing the lower end Pr of the printing paper P. As described above, when printing the lower end Pr of the printing paper P, the lower end Pr of the printing paper P is 7 from the downstream end in the sub-scanning direction among the rasters on which the nozzle on the print head 28 can record dots. It is in the position of the second raster (see Figure 12). That is, the lower end of the printing paper P is located 6 rasters before the nozzle # 8. Therefore, in this state, it is assumed that the bottom row of the printable area and the second raster from the bottom row (the sixth and fifth rasters from the bottom in FIG. 12) are recorded. The ink droplet Ip ejected from the nozzle of No. 1 will fall as it is into the groove portion 26f on the upstream side.

【0064】

Also, even if the printing paper P is fed less than the original feed amount for some reason, the rasters # 7 and # 8 are set beyond the lower end Pr of the printing paper P (Fig. 12). Since the ink droplet Ip is ejected to the fifth and sixth rasters from the bottom), an image can be recorded on the lower end Pr of the printing paper P, and no margin is formed. That is, as shown by the alternate long and short dash line in FIG. 14, when the insufficient feed amount is 2 rasters or less, a margin is not formed at the lower end of the printing paper P.

【0065】

The two rasters above the assumed upper edge position of the paper (the seventh and eighth rasters from the bottom in FIG. 12) are to be recorded by the nozzles # 7 and # 8. Therefore, even if the printing paper P is fed more than the original feed amount for some reason, the ejected ink droplet Ip may fall into the upstream groove portion 26f and land on the upper surface portion of the platen 26. Absent.

【0066】

Further, in this embodiment, the position of the seventh raster from the downstream end in the sub-scanning direction among the rasters on which the nozzle on the print head 28 can record dots (that is, two rasters of nozzle # 7 in FIG. 14). The last raster on the printing paper is recorded with the lower edge Pr of the printing paper located at the previous position), and printing ends (see Fig. 12). Therefore, while the printing paper P is fed by the distance of L41 from when the lower end Pr of the printing paper P leaves the upstream paper feed rollers 25a and 25b to the position shown in FIG. 14, only the downstream paper feed rollers 25c and 25d are fed. Sub-scan feed is performed and printing is executed. In this embodiment, the sub-scanning feed is performed only by the downstream paper feed rollers 25c and 25d, and the section in which printing is executed is relatively short, so that the print result becomes high quality. In particular, the downstream paper feed roller 25d is a gear-shaped roller, and the combination of the downstream paper feed rollers 25c and 25d has lower feed accuracy than the upstream paper feed rollers 25a and 25b. Therefore, it is very effective for improving the quality of the print result that the sub-scanning feed is performed only by the downstream paper feed rollers 25c and 25d and the section in which printing is executed is relatively short. In addition to the above-described embodiment, the above-mentioned effect can be obtained by printing the vicinity of the lower end Pr of the printing paper with a nozzle near the upstream end in the sub-scanning direction. It is particularly effective when the feed accuracy of the downstream sub-scanning drive unit (downstream side paper feed rollers 25c, 25d) is relatively low.

【0067】

Further, when printing the lower end portion, the printing paper P is supported by two places, the downstream side paper feed rollers 25c and 25d and the upper surface of the platen 26. Therefore, the lower end portion of the printing paper P is relatively less likely to bend downward on the upstream groove portion 26f. Therefore, it is unlikely that the quality of the print result at the upper end portion will deteriorate due to the bending of the printing paper.

【0068】

(iv) Bottom Feed of Comparative Example: FIG. 15 is a side view showing the relationship between the print head 28 and the printing paper P when printing the lower end Pr of the printing paper P in the comparative example. As shown in FIG. 15, even if the lower end portion of the printing paper P is printed on the downstream groove portion 26r, the ink droplets that have not landed on the printing paper P do not land on the upper surface of the platen 26. However, in the comparative example, as shown in FIG. 15, the distance L42 at which the printing paper is fed from the time when the lower end of the printing paper leaves the upstream paper feed rollers 25a and 25b to the end of printing is the case of the embodiment ( It is longer than L41) in Fig. 14. That is, the sub-scan feed is performed only by the downstream paper feed rollers 25c and 25d, which have relatively low feed accuracy, and the section in which printing is executed is long. Therefore, the quality of the print result is lower than that of the examples.

【0069】

Further, when printing the lower end portion, the printing paper P is held only by the downstream side paper feed rollers 25c and 25d. Therefore, the lower end portion of the printing paper P tends to bend downward on the downstream groove portion 26r. Therefore, when printing the lower end portion, there is a relatively high possibility that the quality of the print result is deteriorated.

【0070】

C. Second Example: FIG. 16 is a side view showing the relationship between the print head 28a, the upstream groove 26fa, and the downstream groove 26ra in the second embodiment. Here, a case where the upper end processing and the lower end processing are performed in a printing apparatus in which one row of nozzles has 11 nozzles will be described. In the printing apparatus used here, the downstream groove portion 26ra is provided at a position facing the nozzles # 1 to # 3 in the sub-scanning direction. Further, the upstream groove portion 26fa is provided at a position facing the nozzles # 9 to # 11. The other points are the same as those of the printing apparatus described above. Further, in this second embodiment, overlap printing is not performed. That is, each raster is recorded with one nozzle in one main scan.

【0071】

(1) Top treatment of the second embodiment: FIGS. 17 and 18 are explanatory views showing how each raster is recorded by which nozzle in the top treatment of the second embodiment. 17 and 18 show how the head records the raster, divided into upper and lower parts. The lower part of FIG. 17 leads to the upper part of FIG. The 38th to 42nd rasters from the top are duplicated in FIGS. 17 and 18.

【0072】

As shown in FIG. 17, in the upper end processing of the second embodiment, the sub-scanning feed of 3 dots is repeated 11 times. This upper end processing is printing in the "first recording mode" in the claims. In this upper end processing, no nozzles other than the nozzles # 1 to # 3 of the print head 28a are used. The nozzle surrounded by a thick frame in the figure is a nozzle that records dots on the raster.

【0073】

After that, the "transition process" is performed before the intermediate process is performed, instead of immediately performing the intermediate process. In this transition process, the sub-scan feed of 3 dots is performed four times as in the case of the upper end process. In the transition process, all nozzles # 1 to # 11 are used. After that, as shown in FIG. 18, the process shifts to the intermediate processing, and the regular feed of 11 dots is repeated. This intermediate process is printing in the "second recording mode" as defined in the claims.

【0074】

In FIG. 17, the nozzles of the second, third, and sixth rasters from the top do not pass through the main scan during printing. Therefore, for the rasters from the top to the sixth, it is not possible to print pixels continuously on adjacent rasters. In this embodiment, these six rasters are "non-printable areas". For rasters through which two or more nozzles pass, such as the 13th and 16th rasters from the top, only the nozzle that passes through the last raster shall record dots.

【0075】

In the second embodiment, among the rasters in which the nozzle on the print head 28a can record dots, the raster (printable area) 7th or later from the upstream end in the sub-scanning direction is used to record an image. it can. Therefore, the image data D used for printing is set from the seventh raster from the upstream end in the sub-scanning direction. However, for the same reason as in the first embodiment, printing starts when the upper end of the printing paper P is at the 23rd raster position, not at the 7th position from the upstream edge in the sub-scanning direction. .. That is, as shown in FIG. 17, the assumed position of the upper end of the printing paper P with respect to each raster at the start of printing is the position of the 23rd raster from the upstream end in the sub-scanning direction. Therefore, in the second embodiment, the image data D is provided for 16 rasters beyond the assumed position of the upper end of the printing paper P. Therefore, even if an error occurs in the feeding of the printing paper P and the extra printing paper P is fed, if the error is within 16 rasters, the image is formed without a margin up to the upper end of the printing paper P. Can be done.

【0076】

Further, in the second embodiment, 16 rasters set beyond the assumed upper end position of the printing paper P and 20 rasters from the upper end position are recorded only by nozzles # 1 to # 3. A downstream groove portion 26ra is provided below the nozzles # 1 to # 3. Therefore, even if the ink droplets are ejected to the above-mentioned 16 rasters set beyond the assumed position of the upper end of the printing paper P (that is, in the range where the printing paper does not exist), the ink droplets are discharged on the platen 26a. It will not land. Further, even if ink droplets are ejected to the raster assigned to the upper end of the printing paper P in a state where the printing paper P is not fed to the expected position due to an error in the feeding of the printing paper P, the feed is fed. If the error is within 20 rasters, the ink droplets will not land on the platen 26a.

【0077】

(2) Lower end processing of the second embodiment: FIGS. 19 and 20 are explanatory views showing how each raster is recorded by which nozzle in the lower end processing of the second embodiment. FIG. 19 shows the sub-scan feed after the n + 1th time. 19 and 20 show how the head records the raster, divided into upper and lower parts. The lower part of FIG. 19 connects to the upper part of FIG. 20. The 45th to 40th rasters from the bottom are duplicated in FIGS. 19 and 20.

【0078】

In this embodiment, as shown in FIGS. 19 and 20, after the regular feed of 11 dots is repeated in the sub-scan feed from the n + 1th to the n + 3 times in the intermediate processing, the feed of 3 dots in the transition processing is performed. Repeat 4 times. After that, in the lower end processing, only nozzles # 9 to # 11 are used to feed 3 dots.

【0079】

In the second embodiment, as shown in FIG. 20, an image is recorded using the seventh or higher raster (printable area) from the bottom among the rasters on which the nozzle on the print head 28 can record dots. can do. However, in the second embodiment, the image is recorded using the eighth or higher raster from the bottom. That is, the eighth or higher rasters from the bottom of FIG. 20 are print areas, and image data is set for those rasters.

【0080】

Further, in FIG. 20, the 13th and 16th rasters from the bottom pass through two or more nozzles in the main scan during printing. For such rasters through which two or more nozzles pass in printing, the nozzles that first pass over the raster record dots.

【0081】

In the second embodiment, among the rasters on which the nozzles on the print head 28a can record dots, the eighth or higher raster from the downstream end in the sub-scanning direction can be used to record an image. Therefore, the image data D used for printing is set up to the eighth raster. However, for the same reason as in the first embodiment, printing ends when the lower end of the printing paper P is at the 38th raster position, not at the 8th position from the downstream edge in the sub-scanning direction. .. That is, as shown in FIG. 20, the assumed position of the lower end of the printing paper P for each raster at the end of printing is the position of the 38th raster from the downstream end in the sub-scanning direction. Therefore, in the second embodiment, the image data D is provided for 30 rasters beyond the assumed position of the lower end of the printing paper P. Therefore, even if an error occurs in the feeding of the printing paper P and the printing paper P is not fed to the assumed position, if the error is within 30 rasters, the image can be formed without a margin to the lower end.

【0082】

Further, in the second embodiment, 30 rasters set beyond the assumed position of the lower end of the printing paper P and 20 rasters upstream from the lower end position are recorded only by nozzles # 9 to # 11. .. An upstream groove portion 26fa is provided below the nozzles # 9 to # 11. Therefore, even if the ink droplets are ejected to the raster set beyond the assumed position of the lower end of the printing paper P (that is, in the range where the printing paper does not exist), the ink droplets will land on the platen 26a. Never. In addition, even if ink droplets are ejected to the raster assigned to the lower end of the printing paper P in a state where an error occurs in the feeding of the printing paper P and the extra printing paper P is fed, the feed is fed. If the error is within 20 rasters, the ink droplets will not land on the platen 26a.

【0083】

When recording the lower end side of the printing paper P, the printing paper P is sent a longer distance than when recording the upper end side of the printing paper P. Therefore, when recording the lower end side of the printing paper P, it is highly possible that the error in the position of the printing paper P is larger than when recording the upper end side of the printing paper P. Further, the downstream side paper feed roller 25d is a gear-shaped roller, and the combination of the downstream side paper feed rollers 25c and 25d has lower feed accuracy than the upstream side paper feed rollers 25a and 25b. Therefore, from this point as well, there is a high possibility that the error in recording the lower end side is larger than the error in the position of the printing paper P when recording the upper end side. Therefore, as in the second embodiment, the number of rasters recorded only by the nozzles (# 9 to # 11) on the upstream groove 26fa at the lower end of the printing paper P is set to the downstream groove at the upper end of the printing paper P. It is preferable to set more than the number of rasters recorded only by the nozzles (# 1 to # 3) on the part 26ra. Then, in the image data D, it is preferable to set the number of rasters set beyond the lower end of the printing paper P to be larger than the number of rasters set beyond the upper end of the printing paper P.

【0084】

D. Third Example: FIG. 21 is a side view showing the relationship between the print head 28b, the upstream groove portion 26fb, and the downstream groove portion 26rb in the third embodiment. Here, a case where upper end processing and lower end processing are performed in a printing apparatus in which one row of nozzles has 48 nozzles will be described. In the printing apparatus used here, the downstream groove portion 26rb is provided at a position facing the nozzles # 1 to # 12 in the sub-scanning direction. Further, the upstream groove portion 26fb is provided at a position facing the nozzles # 37 to # 48. The other points are the same as those of the printing apparatus described above.

【0085】

FIG. 22 is an explanatory diagram showing the arrangement of the inkjet nozzles Nz in the ink ejection heads 61b to 66b in the third embodiment. In this third embodiment, the pitch of each nozzle and the pitch of the raster are the same. Therefore, the printhead 28b can record dots on adjacent rasters in one main scan. In FIG. 22, the range facing the downstream groove 26rb on the platen 26b is indicated by Rr, and the range facing the upstream groove 26fb is indicated by Rf. The nozzles existing in the range Rr are nozzles # 1 to # 12, and the nozzles existing in the range Rf are nozzles # 37 to # 48. In the third embodiment, overlap printing is performed using the print head 28b.

【0086】

(1) Top treatment of the third embodiment: FIGS. 23 and 24 are explanatory views showing how each raster is recorded by which nozzle in the top treatment of the third embodiment. The lower part of FIG. 23 connects to the upper part of FIG. 24. The rasters from the 66th to the 74th from the top are described in duplicate.

【0087】

As shown in FIG. 23, in the upper end processing of the third embodiment, the sub-scanning feed of 6 dots is repeated 10 times. This upper end processing is printing in the "first recording mode" in the claims. Nozzles other than the nozzles # 1 to # 12 of the print head 28b are used in this upper end processing. The nozzle surrounded by the thick frame in the figure is the nozzle that records dots on the raster. The nozzle used in the upper end treatment is the nozzle shown as the nozzle group N1 in FIG.

【0088】

After that, the "migration process" is performed. In this transition process, the 6-dot sub-scan feed is performed twice as in the case of the upper end process. In the transition process, after the first feed, dots are recorded with the # 1 to # 12 nozzles as in the case of the upper end process. Then, after the second feed, the # 1 to # 30 nozzles are used. After that, as shown in FIG. 24, the process shifts to the intermediate processing, and the regular feed of 24 dots is repeated. In the intermediate treatment, all nozzles # 1 to # 48 are used. This intermediate process is printing in the "second recording mode" as defined in the claims. The nozzle used after the second feed of the transition process is the nozzle shown as the nozzle group N2 in FIG. 22. The nozzle used in the intermediate treatment is the nozzle shown as the nozzle group N3 in FIG. 22.

【0089】

In FIG. 23, for the rasters from the top to the sixth, overlap printing cannot be performed because the nozzles pass only once in the main scan during printing. In this embodiment, these six rasters are "non-printable areas". For rasters through which two or more nozzles pass, such as the 13th and subsequent rasters from the top, only the nozzle that passes through the raster last and the nozzle that passes through the raster immediately before that shall record dots. ..

【0090】

In the third embodiment, the image data D used for printing is set from the seventh raster from the upstream end in the sub-scanning direction, which is the upper end of the printable area. However, for the same reason as in the first embodiment, printing starts when the upper end of the printing paper P is at the position of the 37th raster from the upstream edge in the sub-scanning direction. The position is shown in FIG. 23 as an assumed position of the upper end of the printing paper P. That is, in the third embodiment, the image data D is provided for 36 rasters beyond the assumed position of the upper end of the printing paper P. Therefore, even if an error occurs in the feeding of the printing paper P and the extra printing paper P is fed, if the error is within 36 rasters, the image is formed without a margin up to the upper end of the printing paper P. Can be done.

【0091】

Further, in the third embodiment, 36 rasters set beyond the assumed upper end position of the printing paper P and 42 rasters from the upper end position are nozzles # 1 to # 12 on the downstream groove 26rb. Recorded only in. Therefore, even if the ink droplets are ejected to the above-mentioned 36 rasters set beyond the assumed position of the upper end of the printing paper P (that is, in the range where the printing paper does not exist), the ink droplets are discharged on the platen 26a. It will not land. Further, even if ink droplets are ejected to the raster assigned to the upper end of the printing paper P in a state where the printing paper P is not fed to the expected position due to an error in the feeding of the printing paper P, the feed is fed. If the error is within 42 rasters, ink droplets will not land on the platen 26b.

【0092】

(2) Lower end processing of the third embodiment: FIGS. 25 and 26 are explanatory views showing how each raster is recorded by which nozzle in the lower end processing of the third embodiment. The lower part of FIG. 25 connects to the upper part of FIG. 26.

【0093】

In this embodiment, as shown in FIG. 25, after repeating the regular feed of 24 dots in the intermediate process, the feed of 6 dots is performed once in the transition process. The nozzles used after the feed are # 19 ~ # 48. After that, in the lower end processing, 6 dots are fed using only nozzles # 37 to # 48. The nozzle used after the feed of the transition process is the nozzle shown as the nozzle group N4 in FIG. 22. The nozzle used in the lower end processing is the nozzle shown as the nozzle group N5 in FIG. 22.

【0094】

In the third embodiment, as shown in FIG. 26, an image is recorded using the seventh or higher raster (printable area) from the bottom among the rasters on which the nozzle on the print head 28 can record dots. can do. However, in the third embodiment, the image is recorded using the ninth or higher raster from the bottom. That is, the ninth or higher rasters from the bottom of FIG. 26 are print areas, and image data is set for those rasters.

【0095】

Further, in FIG. 26, two or more nozzles pass through the thirteenth or higher raster from the bottom in the main scan during printing. For such rasters through which two or more nozzles pass in printing, the nozzles that first pass over the raster and then the nozzles that pass through the raster record dots.

【0096】

In the third embodiment, the image data D used for printing is set up to the ninth raster from the bottom. However, for the same reason as in the first embodiment, printing ends when the lower end of the printing paper P is at the 49th raster position, not at the 9th position from the downstream edge in the sub-scanning direction. .. FIG. 26 shows the assumed position of the lower end of the printing paper P for each raster at the end of printing. Therefore, in the third embodiment, the image data D is provided for 40 rasters beyond the assumed position of the lower end of the printing paper P. Therefore, even if an error occurs in the feeding of the printing paper P and the printing paper P is not fed to the assumed position, if the error is within 40 rasters, the image can be formed without a margin to the lower end.

【0097】

Further, in the third embodiment, 40 rasters set beyond the assumed position of the lower end of the printing paper P and 36 rasters on the upstream side from the position of the lower end are nozzles # 37 ~ on the upstream groove portion 26fb. Recorded only in # 48. Therefore, even if the ink droplets are ejected to the raster set beyond the assumed position of the lower end of the printing paper P (that is, in the range where the printing paper does not exist), the ink droplets will land on the platen 26b. Never. In addition, even if ink droplets are ejected to the raster assigned to the lower end of the printing paper P in a state where an error occurs in the feeding of the printing paper P and the extra printing paper P is fed, the feed is fed. If the error is within 36 rasters, ink droplets will not land on the platen 26a.

【0098】

Also in the third embodiment, the number of rasters recorded only by the nozzles (# 37 to # 48) on the upstream groove 26fb at the lower end of the printing paper P is the number of rasters recorded only by the nozzles (# 37 to # 48) at the upper end of the printing paper P. It is set more than the number of rasters recorded only by nozzles (# 1 to # 12) on 26rb. Then, in the image data D, the number of rasters set beyond the lower end of the printing paper P is set larger than the number of rasters set beyond the upper end of the printing paper P.

【0099】

E. Aspect having a lateral groove: In the above, as shown in FIG. 7, in a printer 22 having an upstream groove 26f and a downstream groove 26r on the platen 26, an image set beyond the upper and lower ends of the printing paper P. A mode of printing was described based on the data D (see FIG. 9). Here, in a printer 22n having a left groove 26na and a right groove 26nb on a platen in addition to the upstream groove 26f and the downstream groove 26r, it is based on the image data Dn set beyond the upper and lower ends and the left and right edges of the printing paper P. The mode of printing will be described.

【0100】

FIG. 27 is a plan view showing the relationship between the image data Dn and the printing paper P. In FIG. 27, the image data Dn is set not only at the upper end Pf and the lower end Pr of the printing paper P but also beyond the left end Pa and the right end Pb to the outside of the printing paper P. As a result, in this embodiment, the relationship between the size of the image data Dn and the printing paper P and the assumed position of the image data Dn at the time of printing and the arrangement of the printing paper P is shown in FIG. 27. The width of the image (width of the extended area) that can be recorded by this image data Dn has a width that exceeds the left and right edges of the printing paper P and exceeds the distance between the outer side walls of the left groove portion 26na and the right groove portion 26nb. Has no width. Since the left and right names of the left edge Pa and the right edge Pb correspond to the left and right names of the printer 22, the actual left and right and left edge Pa and right edge Pb names are used in the printing paper P. It's the other way around.

【0101】

FIG. 28 is a plan view showing the periphery of the platen 26n of the printer 22n. The printer 22n includes guides 29a and 29b that guide the printing paper P to maintain a predetermined position in the main scanning direction during the sub-scanning of the printing paper P. Further, the platen 26n is provided with an upstream groove portion 26f and a downstream groove portion 26r, similarly to the platen 26 in FIG. Further, the platen 26n is provided with a left groove 26na and a right groove 26nb extending in the sub-scanning direction so as to connect both ends of the upstream groove 26f and the downstream groove 26r. The left groove portion 26na and the right groove portion 26nb are provided in a range in the sub-scanning direction that is longer than the landing range of ink droplets from the nozzle row on the print head. The left groove portion 26na and the right groove portion 26nb are provided so that the distance between the center lines (in the main scanning direction) is equal to the width of the printing paper P in the main scanning direction. Other configurations are the same as those of the printer 22 described above.

【0102】

In the left groove portion 26na and the right groove portion 26nb, when the printing paper P is at a predetermined main scanning position guided by the guides 29a and 29b, one side end Pa in the main scanning direction of the printing paper P is the left groove portion. It may be provided so as to be located above the opening of 26na and the other side end Pb is located above the opening of the right groove 26nb. Therefore, the left groove 26na and the right groove 26nb have the printing paper P other than the aspect in which the side ends of the left groove 26na and the right groove 26nb are on the center line of the left groove 26na and the right groove 26nb when the printing paper P is in a fixed position as described above. The side end portion of the left side groove portion 26na and the right side groove portion 26nb may be provided so as to be located inside or outside the center line.

【0103】

These upstream groove 26f, downstream groove 26r, left groove 26na and right groove 26nb are connected to each other to form a quadrilateral groove. An absorbing member 27 for receiving the ink droplet Ip and absorbing the ink droplet Ip is arranged at the bottom thereof.

【0104】

The printing paper P passes over the openings of the upstream side groove portion 26f and the downstream side groove portion 26r when the sub-scanning feed is performed by the upstream side paper feed rollers 25a and 25b and the downstream side paper feed rollers 25c and 25d. .. Further, the printing paper P is positioned in the main scanning direction by the guides 29a and 29b so that the left end Pa is located on the left groove 26na and the right end Pb is located on the right groove 26nb on the platen 26n. Has been done. Therefore, during the sub-scanning feed, the printing paper P is fed while maintaining its positions on the openings of the left groove portion 26na and the right groove portion 26nb, respectively.

【0105】

Also in the aspect of FIG. 28, regarding the feed of the sub-scanning of the upper end treatment and the lower end treatment, the feed of the first to third embodiments described above is performed according to the relative positional relationship between each nozzle of the nozzle row and the platen 26n. be able to. Therefore, in the following, printing of the side end portions Pa and Pb of the printing paper P will be described.

【0106】

FIG. 29 is an explanatory diagram showing printing of the left and right side edges of the printing paper P. In the aspect of FIG. 28, printing is performed so that no margins are provided at the left and right edges of the printing paper P throughout the entire recording of the image on the printing paper P, including the upper end processing and the lower end processing. At that time, in the main scanning, the print head 28 is fed to a position where all the nozzles of one end are beyond the edge of the printing paper P and are located outside the printing paper P, and also at the other end. All nozzles are fed beyond the other edge of the printing paper P to the outside of the printing paper P. Then, not only when the nozzle Nz is on the printing paper P, but also when the nozzle Nz is at a position beyond the edge of the printing paper P and is on the left groove portion 26na or the right groove portion 26nb, the image data Ink droplets are ejected from the nozzle Nz according to Dn. The image area (extended area) of the image data Dn has a width exceeding the left and right edges of the printing paper P and a width not exceeding the distance between the outer side walls of the left groove portion 26na and the right groove portion 26nb. .. Therefore, even when the nozzle is on the left side groove portion 26na or the right side groove portion 26nb on the outside of the printing paper P, the ink droplets can be ejected according to the image data Dn.

【0107】

By performing such printing, even if the printing paper P is slightly displaced in the main scanning direction, an image can be formed without creating margins at both left and right ends of the printing paper P. Since the nozzles that print both ends of the printing paper are the nozzles located on the left groove 26na or the right groove 26nb, even if the ink droplets come off the printing paper P, the ink droplets are still in the center of the platen 26. It lands on the left groove 26na or the right groove 26nb without landing on 26c. Therefore , the printing paper P is not contaminated by the ink droplets that land on the central portion 26c of the platen 26.

【0108】

F. Modifications: The present invention is not limited to the above examples and embodiments, and can be implemented in various embodiments without departing from the gist thereof. For example, the following modifications are also possible. It is possible.

【0109】

F1. Modification 1: In the first embodiment, the regular feed of 1 dot is performed in the upper end processing and the lower end processing, in the second embodiment, the regular feed of 3 dots is performed, and in the third embodiment, the regular feed of 6 dots is performed. went. However, the feed of the upper end processing and the lower end processing is not limited to this, and can be a regular feed of 2 dots, 4 dots, or 5 dots depending on the number of nozzles in the nozzle row and the nozzle pitch. That is, any feed may be used as long as the maximum sub-scan feed amount is smaller than the maximum sub-scan feed amount in the intermediate processing. However, the smaller the feed amount of the sub-scanning feed of the upper end processing, the more the upper end of the printing paper can be recorded by the nozzle on the downstream side in the sub-scanning direction. Therefore, the groove on the downstream side can be narrowed, and the upper surface of the platen that supports the printing paper can be widened. Similarly, the smaller the feed amount of the sub-scanning feed for the lower end processing, the more the upper end of the printing paper can be recorded by the nozzle on the upstream side. Therefore, the groove on the upstream side can be narrowed, and the upper surface of the platen that supports the printing paper can be widened.

【0110】

Further, the feed in the intermediate processing is not limited to the irregular feed in which the feed of 5 dots, 2 dots, 3 dots, and 6 dots is repeated in that order, the regular feed of 11 dots, and the regular feed of 24 dots. For example, in the configuration shown in the first embodiment, the feed may be 5 dots, 3 dots, 2 dots, or 6 dots. Further, it is possible to adopt a combination of other feed amounts according to the number of nozzles, the nozzle pitch, and the like, and it is also possible to carry out regular feed of another feed amount. That is, any sub-scan feed may be performed as long as the maximum sub-scan feed amount is larger than the maximum sub-scan feed amount in the upper end processing or the lower end processing.

【0111】

F2. Modification 2: In the above embodiment, the image set beyond the edge of the printing paper has two rasters on both the upper end side and the lower end side in the first embodiment, and the upper end side in the second embodiment. There were 16 rasters and 30 rasters on the lower end side. Then, in the third embodiment, the upper end side was 30 rasters and the lower end side was 40 rasters. However, the size of the image set beyond the edge of the printing paper is not limited to this. For example, the width of the portion of the image data D set beyond the upper end Pf of the printing paper P to the outside of the printing paper P can be equivalent to 1/2 the width of the downstream groove portion 26r. Similarly, the width of the portion of the image data D set beyond the lower end Pr of the printing paper P to the outside of the printing paper P can be equivalent to 1/2 the width of the upstream groove portion 26f. That is, the width of the image data portion set beyond the edge of the printing paper to the outside of the printing paper may be smaller than the width of the downstream groove 26r on the upper end side, and the upstream groove 26f on the lower end side. It should be smaller than the width of. By doing so, even if the edge of the printing paper P is not at the expected position, the ink droplet Ip for recording the set image beyond the printing paper P may land on the upper surface of the platen 26. Absent. However, if the width of the groove is halved, the same amount of deviation can be tolerated regardless of whether the printing paper P is displaced to the upstream side or the downstream side.

【0112】

Similarly, for the left and right side edges, the width of the image data portion set beyond the edges of the printing paper to the outside of the printing paper may be smaller than the width of the left groove portion 26na and the right groove portion 26nb. If the width of the groove is halved, the same amount of deviation can be tolerated regardless of whether the printing paper P is displaced to the upstream side or the downstream side.

【0113】

F3. Modification 3: In the above embodiment, both the upper end processing and the lower end processing are executed, but only one of them may be executed if necessary. Further, the printing apparatus of this embodiment is provided with the upstream side groove portion 26f and the downstream side groove portion 26r on the upstream side and the downstream side of the platen 26 in the sub-scanning direction, respectively, but only one of them may be provided. ..

【0114】

F4. Modification 4: In the above embodiment, a part of the configuration realized by the hardware may be replaced with software, and conversely, a part of the configuration realized by the software may be replaced with the hardware. You may do so. For example, the host computer 90 can perform some of the functions of CPU 41 (Fig. 5).

【0115】

A computer program that realizes such a function is provided in a form recorded on a computer-readable recording medium such as a floppy disk or a CD-ROM. The host computer 90 reads a computer program from the recording medium and transfers it to an internal storage device or an external storage device. Alternatively, the computer program may be supplied from the program supply device to the host computer 90 via the communication path. When the function of the computer program is realized, the computer program stored in the internal storage device is executed by the microprocessor of the host computer 90. Further, the host computer 90 may directly execute the computer program recorded on the recording medium.

【0116】

In this specification, the host computer 90 is a concept including a hardware device and an operating system, and means a hardware device operating under the control of the operating system. The computer program causes such a host computer 90 to realize the functions of the above-mentioned parts. It should be noted that some of the above-mentioned functions may be realized by the operating system instead of the application program.

【0117】

In the present invention, the "computer-readable recording medium" is not limited to a portable recording medium such as a flexible disk or a CD-ROM, but also an internal storage device in a computer such as various RAMs or ROMs, or an internal storage device in a computer. It also includes external storage devices such as hard disks that are fixed to the computer.

[Simple explanation of drawings]

[Figure 1]

FIG. 5 is a side view showing a structure around a print head of an inkjet printer according to an embodiment of the present invention.

[Figure 2]

It is explanatory drawing which shows the state of printing at the lower end Pr of the printing paper P.

[Fig. 3]

The block diagram which shows the structure of the image processing apparatus and the printing apparatus as an Example of this invention.

[Fig. 4]

The block diagram which shows the software structure of this printing apparatus.

[Fig. 5]

The figure which shows the structure of the mechanical part of this printing apparatus.

[Fig. 6]

The plan view which shows the example of the arrangement of the nozzle unit for each color in a print head unit 60.

[Fig. 7]

Top view showing the periphery of platen 26.

[Fig. 8]

Explanatory drawing which shows how each raster is recorded by which nozzle near the upper end (tip) of printing paper.

[Fig. 9]

The plan view which shows the relationship between image data D and printing paper P.

[Fig. 10]

The side view which shows the relationship between the print head 28 and the printing paper P at the start of printing.

[Fig. 11]

The side view which shows the relationship between the print head 28 and the printing paper P at the start of printing in a comparative example.

[Fig. 12]

Explanatory drawing which shows how each raster is recorded by which nozzle in the lower end processing.

[Fig. 13]

The plan view which shows the relationship between the upstream groove 26f and the printing paper P when printing the lower end Pr of the printing paper P.

[Fig. 14]

The side view which shows the relationship between the printing head 28 and printing paper P when printing at the lowermost end of printing paper.

[Fig. 15]

The side view which shows the relationship between the print head 28 and the print paper P when printing at the lowermost end of the print paper in the comparative example.

[Fig. 16]

The side view which shows the relationship between the print head 28a, the upstream side groove part 26fa, and the downstream side groove part 26ra in the 2nd Example.

[Fig. 17]

Explanatory drawing which shows how each raster is recorded by which nozzle in the upper end processing of 2nd Example.

[Fig. 18]

Explanatory drawing which shows how each raster is recorded by which nozzle in the upper end processing of 2nd Example.

[Fig. 19]

Explanatory drawing which shows how each raster is recorded by which nozzle in the lower end processing of 2nd Example.

[Fig. 20]

Explanatory drawing which shows how each raster is recorded by which nozzle in the lower end processing of 2nd Example.

[Fig. 21]

The side view which shows the relationship between the print head 28b, the upstream side groove part 26fb, and the downstream side groove part 26rb in the 3rd Example.

[Fig. 22]

The explanatory view which shows the arrangement of the inkjet nozzle Nz in the ink ejection head 61b to 66b in the 3rd Example.

[Fig. 23]

Explanatory drawing which shows how each raster is recorded by which nozzle in the upper end processing of 3rd Example.

[Fig. 24]

Explanatory drawing which shows how each raster is recorded by which nozzle in the upper end processing of 3rd Example.

[Fig. 25]

Explanatory drawing which shows how each raster is recorded by which nozzle in the lower end processing of 3rd Example.

[Fig. 26]

Explanatory drawing which shows how each raster is recorded by which nozzle in the lower end processing of 3rd Example.

[Fig. 27]

A plan view showing the relationship between the image data Dn and the printing paper P.

[Fig. 28]

Top view showing the periphery of the platen 26n of the printer 22n.

[Fig. 29]

Explanatory drawing which shows printing of the left-right side end part of printing paper P.

[Fig. 30]

A side view showing the periphery of the print head of a conventional printer.

[Explanation of symbols]

12 ... Scanner 14 ... keyboard 15 ... Flexible drive 16 ... Hard disk 18 ... Modem 21 ... CRT 22,22n ... Printer 23 ... Paper feed motor 24 ... Carriage motor 25a, 25b ... Upstream paper feed roller 25c, 25d ... Downstream paper feed roller 25p, 25q ... Upstream paper feed roller 25r, 25s ... Downstream paper feed roller 26,26a, 26b, 26n, 26o ... Platen 26c ... Central 26f, 26fa, 26fb ... upstream groove 26na ... left groove 26nb ... Right groove 26r, 26ra, 26rb ... Downstream groove 27,27f, 27r ... Absorbent member 28,28a, 28b, 28o ... Print head 29a, 29b ... Guide 31 ... Carriage 32 ... Operation panel 34 ... Sliding shaft 36 ... drive belt 38 ... pulley 39 ... Position detection sensor 40 ... control circuit 41 ... CPU 42 ... PROM 43 ... RAM 44 ... Drive buffer 45 ... PC interface 60 ... print head unit 61 ~ 66 ... Ink ejection head 61b ~ 66b ... Ink ejection head 67 ... Introduction pipe 68 ... Ink passage 71 ... Cartridge 72 ... Color ink cartridge 80 ... Bus 81 ... CPU 82 ... ROM 83 ... RAM 84 ... Input interface 85 ... Output interface 86 ... CRTC 88 ... SIO 90 ... host computer 91 ... Video driver 95 ... application program 96 ... Printer driver 97 ... resolution conversion module 98 ... Color correction module 99 ... Halftone module 100 ... rasterizer D, Dn ... image data DT ... Dot formation pattern table FD ... Flexible disk Ip ... ink drops L31 ... Distance printed by sub-scanning only by the upstream paper feed roller L41 ... Distance printed by sub-scanning only by the downstream paper feed roller L32 ... Distance printed by sub-scanning only by the upstream paper feed roller L42 ... Distance printed by sub-scanning only by the downstream paper feed roller LUT ... Color correction table N1 ... Nozzle group used for top edge processing N2 ... Nozzle group used in migration process N3 ... Nozzle group used in intermediate processing N4 ... Nozzle group used in migration process N5 ... Nozzle group used for lower end processing Nf ... Upstream nozzle group Nr ... Downstream nozzle group Nz ... Inkjet nozzle ORG ... Original color image data P ... Printing paper PD ... print data PE ... Piezo element PNT ... Public telephone line Pa ... Left end (part) Pb ... Right end (part) Pf ... Top (part) Pr ... Lower end (part) R26 ... The range where the central part of the platen is provided Rf ... Range where the upstream groove is provided Rr ... Range where the downstream groove is provided SV ... server k ... nozzle pitch