JP2002103585A - Printing up to end part of print sheet without contaminating platen - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology for printing up to the end part of a print sheet without hitting an ink drop against a platen by means of a dot printer recording dots on the surface of a print medium using a dot recording head provided with a plurality of dot forming elements ejecting ink drops. SOLUTION: A platen 26n is provided with grooves 26r, 26f, 26na and 26nb. Nozzles #1 and #2 of a print head 28 pass above a downstream side groove part 26r at the time of main scan feeding in the direction of arrow MS. A print sheet P is guided by means of a guide and sub-scan fed in the direction of arrow SS such that the opposite side ends are located, respectively, above the left and right grooves 26na and 26nb. Image data Dn holds information of image as the information of recording state of dots in each pixel. These pixels are set in a range exceeding the outer circumferential end of the print sheet P. When the print sheet P is sub-scan fed and the forward end thereof reaches a position on the upstream side of the nozzle #1 above the downstream side groove part 26r, printing at the upper end part Pf of the print sheet P is started by means of the nozzles #1 and #2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention 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 up to the end of a printing sheet without soiling a platen.

[0002]

2. Description of the Related Art In recent years, as an output device of a computer,
2. Description of the Related Art Printers that eject ink from nozzles of a print head are widely used. FIG. 29 is a side view showing the periphery of a print head of a conventional printer. The printing paper P is supported on the platen 26o so as to face the head 28o. The printing paper P is supplied to the upstream paper feed rollers 25p and 25q disposed upstream of the platen 26o and the downstream paper feed rollers 25r and 25r disposed downstream of the platen 26.
It is sent in the direction of arrow A by 25s. When ink is ejected from the head, dots are sequentially recorded on the printing paper P, and an image is printed.

[0003]

In order to print an image to the edge of the printing paper without margins in such a printer as described above, image data is set to the edge of the printing paper. It is necessary to arrange such that the end is located below the print head, that is, on the platen, and eject ink droplets from the print head. However, in such printing, when an ink droplet is displaced from the end of the printing paper where it should originally land due to an error in the feeding of the printing paper or a shift in the landing position of the ink droplet, the ink droplet lands on the platen. There is. In such a case, the printing paper that subsequently passes on the platen is stained by the ink that has landed on the platen.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems in the prior art, and has as its object to provide a technique for performing printing up to the end of printing paper without causing ink drops to land on a platen. I do.

[0005]

In order to solve at least a part of the above problems, the present invention uses a dot recording head provided with a plurality of dot forming elements for ejecting ink droplets. A predetermined process is performed on a dot recording apparatus that records dots on the surface of a print medium. This dot recording apparatus is configured to face a dot forming element at least in a part of a main scanning path,
A platen is provided extending in the main scanning direction. The platen has an upstream groove portion provided in the main scanning direction at a position facing the dot forming element positioned at least at the upstream end in the sub-scanning direction among the plurality of dot forming elements; And a downstream groove portion extending in the main scanning direction at a position facing the dot forming element located at least at the downstream end in the sub-scanning direction among the dot forming elements.

When forming dots, at least one of the plurality of dot forming elements is driven to form dots while driving at least one of the dot recording head and the print medium to perform main scanning. The sub-scan is performed by driving the print medium in a direction intersecting with the main scan between scans.
At that time, first, print data including image data for recording an image in an extended area having a length exceeding at least the upper and lower ends of the print medium is prepared. Then, based on the print data, ink droplets are ejected to the extended area. If such printing is performed in the above-described dot recording apparatus, printing can be performed up to the edge of the printing paper without causing ink drops to land on the platen.

[0007] When ejecting ink droplets to the extended area,
When ejecting ink droplets to the upper end of the print medium, the print medium is supported by the platen, and the upper end of the print medium is above the opening of the downstream groove, and the upper end is the downstream end in the sub-scanning direction. It is preferable to set the position of the print medium in the sub-scanning direction so as to be located upstream of the dot forming element in the sub-scanning direction. When ejecting ink droplets to the lower end of the print medium, the print medium is supported by the platen, and the lower end of the print medium is above the opening of the upstream groove, and the lower end of the print medium is used for sub-scanning. It is preferable to set the position of the print medium in the sub-scanning direction so as to be located downstream of the dot forming element at the upstream end in the sub-scanning direction. According to this aspect, the upper end of the print medium is printed on the upstream groove, and the lower end of the print medium is printed on the downstream groove, so that the end of the print medium is printed without soiling the platen. Can be.

Further, a pair of platens are provided in a range including at least a landing range of ink droplets from a plurality of dot forming elements in the sub-scanning direction, and are provided at intervals substantially equal to the width of the print medium. In the case where the side groove portion is provided, the following is preferable. That is, when preparing print data, an image is recorded in an extended area having a width exceeding the left and right ends of the print medium and having a width not exceeding the interval between the outer side walls of the pair of side grooves. Of print data including image data for use. With such an embodiment, printing can be performed without margins on the left and right edges of the print medium.

When the ink droplets are ejected to the extended area, the print medium is supported by the platen, and both ends of the print medium are maintained at positions above the openings of the side grooves. Is preferably set in the main scanning direction. With such an embodiment, the left and right edges of the print medium can be printed without margins without soiling the platen.

[0010] The print data may include, as image data, information on a dot recording state in each pixel in the extended area. With such an embodiment, it is possible to easily set a portion of the extension area beyond the edge of the print medium.

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

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in the following order based on embodiments. A. Overview of Embodiment: First Embodiment: C. First Embodiment Second embodiment D. Third embodiment: Embodiment having a side groove portion: F. Modification:

A. Outline of Embodiment: FIG. 1 is an enlarged plan view showing the structure of a part of the left side of a platen of an ink jet printer according to an embodiment of the present invention. The platen 26n has a downstream groove 26r and an upstream groove 26.
f, left groove 26na, right groove 26nb (not shown)
Are provided so as to form a quadrilateral. The portion surrounded by these grooves is the central portion 26c of the platen 26n. In FIG. 1, the upper surface of the platen where no groove is provided is a portion indicated by a fine diagonal line from upper right to lower left. Also, the nozzle # 1 of the print head 28
And # 2 (indicated by a double circle) indicate that the print head 28 has the arrow MS
When the main scanning feed is performed in the direction of, it passes over the downstream groove 26r. In FIG. 1, the printing paper P is sub-scanned in the direction of the arrow SS from above to below. At this time, the printing paper P is guided by a guide (not shown), and both side ends thereof are formed on the left groove 26n of the platen 26n.
The sub-scan feed is performed so as to be positioned on the right side a and the right groove 26nb.

The image data Dn used for recording an image on the printing paper P is information on the image as the information on the recording state of the dots in each "pixel", which is a square dividing the image area into a grid. I have. In FIG. 1, pixels are indicated by broken lines. As shown in FIG. 1, these pixels are set beyond the outer edge of the printing paper P. In FIG. 1, the printing paper P is a portion indicated by rough oblique lines from upper left to lower right.

When the printing paper P is set on the guide, the printing paper P is sub-scanned in the direction of arrow SS. When the front end reaches the position on the downstream groove 26r and on the upstream side of the nozzle # 1, the sub-scan feed of the printing paper P is stopped. Thereafter, printing of the upper end portion Pf of the printing paper P (in FIG. 1, the printing paper P is located at the lower end side because it is drawn upside down) is started by the nozzles # 1 and # 2. Since the pixels for recording dots are set beyond the upper end Pf of the printing paper P, an image can be formed without creating a margin at the upper end of the printing paper P. Further, since the nozzles # 1 and # 2 used for printing are located on the downstream groove 26r, even if the ink droplets come off the printing paper P, the ink droplets land on the downstream groove 26r and the platen It does not land on the central portion 26c of the 26n. Therefore, the lower surface of the printing paper P is not stained by ink droplets that have landed on the central portion 26c of the platen 26n. Similarly, for the left and right side edges of the printing paper P, printing for pixels set beyond the left and right edges is performed by the left groove portion 26na and the right groove portion 26nb at the time of main scanning.
(Not shown) by a nozzle located above. Therefore, it is possible to print the left and right side edges without blanks without soiling the central portion 26c of the platen 26n.

B. First Embodiment (1) Configuration of Apparatus: FIG. 2 is a block diagram showing a configuration of an image processing apparatus and a printing apparatus according to an embodiment of the present invention. As shown in FIG.
And the printer 22 are connected. When a predetermined program is loaded and executed on the computer 90, the computer 90 functions as an image processing apparatus, and also functions as a printing apparatus together with the printer 22. This computer 90
Is centered on a CPU 81 that executes various arithmetic processes for controlling operations related to image processing according to a program,
The following components are connected to each other by a bus 80. R
The OM 82 previously stores various programs and data necessary for the CPU 81 to execute various arithmetic processes.
The AM 83 is a memory for temporarily reading and writing various programs and data necessary for the CPU 81 to execute various arithmetic processes. The input interface 84 manages input of signals from the scanner 12 and the keyboard 14, and
The output interface 85 manages output of data to the printer 22. CRTC86 is a CRT capable of displaying color
21 to control the signal output to the disk controller (D
The DC 87 controls data transfer between the hard disk 16, the flexible drive 15, and a CD-ROM drive (not shown). The hard disk 16 stores various programs loaded and executed in the RAM 83 and various programs provided in the form of device drivers.

In addition, a serial input / output interface (SIO) 88 is connected to the bus 80. This S
The IO 88 is connected to the modem 18 and the modem 18
Through a public telephone line PNT. The computer 90 is connected to an external network via the SIO 88 and the modem 18. By connecting to a specific server SV, it is also possible to download a program required for image processing to the hard disk 16. In addition, it is also possible to load a necessary program from a flexible disk FD or a CD-ROM and cause the computer 90 to execute the program.

FIG. 3 is a block diagram showing a software configuration of the printing apparatus. In the computer 90, an application program 95 operates under a predetermined operating system. The operating system includes a video driver 91 and a printer driver 96.
Is installed, and the application program 95
Thereafter, the image data D to be transferred to the printer 22 is output via these drivers. Application program 9 for retouching images
5 reads an image from the scanner 12 and performs a predetermined process on the
An image is displayed at T21. Data ORG supplied from the scanner 12 is original color image data ORG that is read from a color original and includes three color components of red (R), green (G), and blue (B).

This application program 95
When a print command is issued, the printer driver 96 of the computer 90 receives the image data from the application program 95 and receives the image data from the application program 95. Is converted to a multilevel signal). In the example shown in FIG. 3, the resolution conversion module 9
7, a color correction module 98, a halftone module 99, and a rasterizer 100. Further, a color correction table LUT and a dot formation pattern table DT are also stored. Note that the application program 95 corresponds to an “image data generation unit”.

The resolution conversion module 97 serves to convert 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. The image data whose resolution has been converted in this way is still RG
Since the image information is composed of the three colors B, the color correction module 98 refers to the color correction table LUT and uses the cyan (C), magenta (M), light cyan (LC), Light magenta (L
M), yellow (Y) and black (K).

The color-corrected data has a gradation value with a width of, for example, 256 gradations. The halftone module 99 executes a halftone process for expressing this gradation value in the printer 22 by forming dots in a dispersed manner. The halftone module 99 refers to the dot formation pattern table DT to set the dot formation pattern of each ink dot according to the gradation value of the image data, and then execute the halftone processing. The image data thus processed is rearranged by the rasterizer 100 in the order of data to be transferred to the printer 22, and output as final print data PD. The print data PD includes raster data indicating the recording state of dots during each main scan and data indicating the sub-scan feed amount. The raster data and the data indicating the sub-scan feed amount included in the print data PD correspond to image data D substantially representing an image to be printed. That is, these data have information on the dot recording state of each pixel in the extended area as image data. In the present embodiment, the printer 22 only plays a role of forming ink dots in accordance with the print data PD, and does not perform image processing. However, it goes without saying that these processes may be performed by the printer 22.

Next, a schematic configuration of the printer 22 will be described with reference to FIG. As shown in the figure, the printer 22 includes a mechanism for transporting a sheet P by a paper feed motor 23 and a carriage 31 by a carriage motor 24 for moving the platen 2.
6, a mechanism for reciprocating in the axial direction, a mechanism for driving a print head 28 mounted on a carriage 31 to discharge ink and form ink dots, a paper feed motor 23, a carriage motor 24, and a print head. 28 and a control circuit 40 for controlling the exchange of signals with the operation panel 32
It is composed of

A mechanism for reciprocating the carriage 31 in the axial direction of the platen 26 is provided in parallel with the axis of the platen 26, and an endless mechanism is provided between a carriage shaft 24 and a slide shaft 34 for slidably holding the carriage 31. And a position detecting sensor 39 for detecting the origin position of the carriage 31.

The carriage 31 includes a cartridge 71 for black ink (K), cyan (C), and light cyan (L).
C), a magenta (M), light magenta (LM), and yellow (Y) ink cartridges 72 containing six color inks can be mounted. The print head 28 below the carriage 31 has a total of six ink ejection heads 61.
Through 66 are formed, and an introduction pipe 67 that guides ink from the ink tank to each color head is provided upright at the bottom of the carriage 31. When the cartridge 71 for black (K) ink and the cartridge 72 for color ink are mounted on the carriage 31 from above, the introduction pipe 67 is inserted into the connection hole provided in each cartridge, and the ejection heads 61 to 66 are discharged from each ink cartridge. Can be supplied to the printer.

The heads 61 to 66 of each color provided below the carriage 31 have 48 nozzles N for each color.
z is provided, and a piezo element PE which is one of the electrostrictive elements and has excellent responsiveness is arranged for each nozzle. The piezo element PE is installed at a position in contact with an ink passage for guiding ink to the nozzle Nz. Piezo element P
As is well known, E is an element whose crystal structure is distorted by the application of a voltage and which converts electric-mechanical energy very quickly. 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 expands for the voltage application time, and deforms one side wall of the ink passage. As a result, the product of the ink passage 68 contracts in accordance with the expansion of the piezo element PE, and the ink corresponding to the contraction is discharged as particles Ip at a high speed from the tip of the nozzle Nz. Printing is performed by the ink particles Ip penetrating into the paper P mounted on the platen 26.

FIG. 5 is an explanatory diagram showing the arrangement of the ink jet nozzles Nz in the ink discharge heads 61 to 66. These nozzles are arranged from six nozzle arrays that eject ink for each color of black (K), cyan (C), light cyan (LC), magenta (M), light magenta (LM), and yellow (Y). 48 nozzles are arranged in a row at a constant nozzle pitch k. The “nozzle pitch” is a value indicating how many rasters (that is, how many pixels) the intervals in the sub-scanning direction of the nozzles arranged on the print head are. For example, the pitch k of the nozzles arranged at intervals of three rasters is four.

FIG. 6 is a plan view showing the periphery of the platen 26. The platen 26 is provided in the main scanning direction longer than the maximum width of the printing paper P usable in the printer. Upstream of the platen 26, upstream paper feed rollers 25a and 25b are provided. While the upstream paper feed roller 25a is a single drive roller, the upstream paper feed roller 25b is a plurality of small rollers that rotate freely. Downstream of the platen, downstream paper feed rollers 25c and 25d are provided. The downstream paper feed roller 25c is a plurality of rollers provided on the drive shaft,
The downstream paper feed roller 25d is a plurality of small rollers that rotate freely. On the outer peripheral surface of the downstream paper feed roller 25d,
A groove is provided in parallel with the rotation axis direction. That is, the downstream paper feed roller 25d has teeth (portions between grooves) radially on the outer peripheral surface, and looks like a gear when viewed from the rotation axis direction. This downstream paper feed roller 25
“d” is generally called “jagged roller” and plays a role of pressing the printing paper P onto the platen 26. The downstream paper feed roller 25c and the upstream paper feed roller 25a rotate synchronously so that the outer peripheral speeds are equal.

The print head 28 is connected to the upstream paper feed rollers 25a and 25b and the downstream paper feed rollers 25.
It reciprocates on the platen 26 sandwiched between c and 25d in the main scanning. The printing paper P is transferred to the upstream paper feed roller 25.
a, 25b and the downstream side paper feed rollers 25c, 25d, and a portion therebetween is supported by the upper surface of the platen 26 so as to face the nozzle row of the print head 28. Then, sub-scan feed is performed by the upstream paper feed rollers 25a and 25b and the downstream paper feed rollers 25c and 25d, and images are sequentially recorded by ink ejected from the nozzles of the print head 28. The upstream paper feed rollers 25a and 25b are "upstream sub-scanning drive units" in the claims, and
5c and 25d are "downstream side sub-scanning drive units" in the claims.

The platen 26 is provided with an upstream groove 26f and a downstream groove 26r on the upstream side and the downstream side in the sub-scanning direction, respectively. The upstream groove 26f and the downstream groove 26r are provided along the main scanning direction longer than the maximum width of the printing paper P usable in the printer. The upstream groove 26f and the downstream groove 2
Absorbing members 27f and 27r for receiving and absorbing the ink droplet Ip are arranged at the bottom of 6r.
The downstream groove 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 (the nozzles indicated by oblique lines in FIG. 6). I have. And the upstream groove 2
6f is provided at a position facing a part of the upstream nozzle group Nf (not shown in FIG. 6) including the most upstream nozzle among the nozzles on the print head 28. When the sub-scan feed is performed by the upstream paper feed rollers 25a and 25b and the downstream paper feed rollers 25c and 25d, the print paper P passes over the openings of the upstream groove portion 26f and the downstream groove portion 26r. Go.

Next, the control circuit 40 of the printer 22 (FIG. 4)
) Will be described. Inside the control circuit 40, in addition to the CPU 41, the PROM 42, and the RAM 43, a PC interface 45 for exchanging data with the computer 90, and a drive for outputting ink dot ON / OFF signals to the ink ejection heads 61 to 66. A buffer 44 and the like are provided, and these elements and circuits are interconnected 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 driving buffer 44 at a predetermined timing. The RAM 43 corresponds to a “print data storage unit” in the claims.

In the printer 22 having the hardware configuration described above, the carriage 31 is reciprocated by the carriage motor 24 while the paper P is conveyed by the paper feed motor 23, and at the same time, the piezo elements of each nozzle unit of the print head 28 are operated. When driven, the ink droplets Ip of each color are ejected, and ink dots are formed to form a multicolor image on the paper P.

In the printer of this embodiment, the upper end Pf of the printing paper P is printed on the downstream groove 26r and the lower end Pr is printed on the upstream groove 26f. In the vicinity, a printing process different from that of the intermediate portion of the printing paper is performed. In this specification, the printing process in the middle portion of the printing paper is called “intermediate process”, the printing process near the top edge of the printing paper is “top edge process”, and the printing process near the bottom edge of the printing paper is “bottom edge process”. Call. When the upper end processing and the lower end processing are collectively called, they are called “upper / lower end processing”.

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

W = p × n + α

Here, p is one 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 a sub-scan feed error 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 processing (upstream groove 26f) is set to be larger than the value of α in the upper end processing (downstream groove 26r). If the width of the groove portion of the platen is determined by the above equation, it is possible to provide a groove portion having a width sufficient to receive ink droplets ejected from the nozzles during upper and lower end processing.

(2). Sub-scan feed: (i) Upper end processing of the first embodiment: FIG. 7 is an explanatory diagram showing how each raster is recorded by which nozzle near the upper end (top end) of the printing paper. Here, for simplicity, the description will be made using only one nozzle row. It is assumed that one nozzle row has eight nozzles. At the time of main scanning, 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 square grid virtually defined on a print medium in order to define a position where an ink droplet lands and a dot is recorded. Here, it is assumed that the nozzles are arranged at intervals of three rasters.

In FIG. 7, one row of cells arranged vertically represents the print head 28. The numbers 1 to 8 in each cell indicate the nozzle number. In the specification, “#” is added to these numbers to indicate each nozzle. In FIG. 7, the print head 28 is relatively fed in the sub-scanning direction with time.
Are sequentially shifted from left to right. As shown in FIG. 7, in the upper end process, the sub-scan feed for each dot is repeated seven times. It should be noted that “dot” as 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 equal to the pitch of the raster.

Thereafter, the processing shifts to the intermediate processing, and 5 dots,
The feeding of 2 dots, 3 dots, and 6 dots is repeated in that order. The method of performing sub-scanning by combining different feed amounts in this way is called “irregular feed”. When the above-described sub-scan feed is performed, each raster is recorded by two nozzles, except for some rasters. That is, in this embodiment, each raster is printed by two nozzles. For example,
In FIG. 7, the fifth raster from the top is recorded by nozzle # 2 and nozzle # 1. At this time, the nozzle # 2 records, for example, an even-addressed pixel, and the nozzle # 1 records an odd-addressed pixel. The ninth raster from the top is recorded by nozzles # 3 and # 2. In this manner, a method of printing by sharing pixels in one raster by a plurality of nozzles is referred to as “overlap printing”. In overlap printing, one raster is
In a plurality of main scans in which the position of the printing paper in the sub-scanning direction with respect to the print head is different from each other, dots are recorded by a plurality of nozzles passing on the raster.

On the other hand, in FIG. 7, the four rasters from the top row only pass the nozzle # 1 once in the main scan during printing. Therefore, for these rasters, it is not possible to print by sharing pixels with two nozzles. Therefore, in this embodiment, these four rasters are not used for recording an image. In other words, the rasters that can be used for recording an image in the present embodiment are the fifth and subsequent rasters from the upstream end in the sub-scanning direction among the rasters on which the nozzles on the print head 28 can record dots. A raster area that can be used to record this image is called a “printable area”.
A raster area that is not used for image recording is referred to as a “non-printable area”. In FIG. 7, the print head 28
Numbers given in order from the top are described on the left side of the figure for rasters on which the upper nozzles can record dots. Or later,
The same applies to the drawings for explaining the printing of dots in the upper end processing. It should be noted that nozzles surrounded by thick frames in the drawing are nozzles that record dots on a raster.

Also, in FIG.
In the fifth raster, three nozzles pass in the main scan during printing. In such a raster in which three or more nozzles pass during printing, it is assumed that only two of the nozzles record dots. It is preferable that these rasters are recorded by nozzles passing over the rasters after shifting to intermediate processing as much as possible. In the intermediate processing, irregular feeding is performed, and the combination of nozzles passing on adjacent rasters is different.
This is because it can be expected that the print result will have high image quality as compared with the upper end process in which the dot-by-dot regular feeding is performed.

In this embodiment, an image is recorded without a margin up to the upper end 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 to print an image. Can be recorded. Therefore, 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 above-mentioned edge is located at a position almost at the upper end of the printing paper, theoretically, Images can be recorded up to the upper end of the printing paper. However, during the sub-scan feed, an error may occur in the feed amount. Further, the ejection direction of the ink droplet may be shifted due to a manufacturing error of the print head or the like. For this reason, it is preferable that no margin is formed at the upper end of the printing paper even when the landing position of the ink droplet on the printing paper is shifted. Therefore, in the present embodiment, the image data D used for printing is
Is set from the fifth raster from the upstream end in the sub-scanning direction among the rasters where the nozzles on the print head 28 can record dots, while the upper end of the printing paper P is It is assumed that printing is started from the state at the position of the seventh raster. Therefore, the assumed position of the upper end of the printing paper with respect to each raster at the start of printing is the position of the seventh raster from the upstream end in the sub-scanning direction, as shown in FIG.

FIG. 8 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 to extend beyond the upper end Pf of the printing paper P to the outside of the printing paper P. For the same reason, the lower end of the printing paper P exceeds the lower end Pr of the printing paper P for the same reason.
Is set up to the outside of the image data. Therefore, in the present embodiment, the size of the image data D and the size of the printing paper P,
FIG. 8 shows the relationship between the image data D and the arrangement of the printing paper P during printing. That is, according to the image data D, an extended area having a length exceeding at least the upper and lower edges of the print medium (an area indicated by a dashed line in FIG. 8).
Images can be recorded on the 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 two rasters. Also,
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 equivalent to two rasters. Note that, in this specification, when the edges of the printing paper P are referred to in correspondence with the upper and lower sides of the image data recorded on the printing paper P,
When using the terms “upper end (part)” and “lower end (part)” and refer to the end of the printing paper P in correspondence with the traveling direction of the sub-scanning feed of the printing paper P on the printer 22, the “front end” (Department) ",
The term "back end (part)" may be used. In the present specification, in the printing paper P, “upper end (part)” corresponds to “front end (part)”, and “lower end (part)” corresponds to “rear end (part)”.

FIG. 9 is a side view showing the relationship between the print head 28 and the printing paper P at the start of printing. Here, the central portion 26c of the platen 26 is provided in a range R26 from a position two rasters later from the nozzle # 2 of the print head 28 to a position two rasters earlier from the nozzle # 7. It is assumed that Therefore, even when the ink droplet Ip is ejected from each nozzle in a state where there is no printing paper,
The ink droplets from the nozzles # 1, # 2, # 7, and # 8 do not land on the platen 26.

In FIG. 6, the nozzle group Nr in the shaded portion of the print head 28 is the portion where the nozzles # 1 and # 2 are located. A downstream groove 26r is provided below a portion through which the nozzles pass during the main scanning, and when the upper end Pf of the printing paper P is at a position indicated by a dashed line on the downstream groove 26r, Printing starts.

As described above, at the start of printing, the upper end Pf of the printing paper P is located 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. It is in. That is, with reference to FIG. 9, the upper end of the printing paper P is located 6 rasters behind the nozzle # 1. In addition,
In FIG. 9, the position of the raster assumed on the image data is indicated by a broken line. Therefore, if printing is to be started from this state, the uppermost raster (the fifth raster from the top in FIG. 7) of the printable area should be recorded by nozzle # 2. There is no printing paper P under the nozzle 2 yet. Therefore, if the printing paper P is correctly fed by the upstream paper feed rollers 25a and 25b, the ink droplet Ip discharged from the nozzle # 2 becomes
It will fall into the downstream groove 26r as it is. Also, as shown in FIG. 7, the uppermost raster of the printable area is recorded by nozzle # 1 after four one-dot feeds. But similarly, 4
At the stage in which the one-dot feed has been performed, there is no print paper P below the nozzle of # 1. Therefore, at that time #
The ink droplet Ip discharged from one nozzle also falls directly into the downstream groove 26r. The same applies to the case of printing the second raster from the top of the printable area (the sixth raster from the top in FIG. 7).

However, for some reason, the printing paper P
If is sent more than the original feed amount,
The upper end of the printing paper P may come to the position of the second raster from the top of the printable area or the uppermost raster of the printable area. In this embodiment, even in such a case, #
Since the nozzles # 1 and # 2 eject the ink droplets Ip to the rasters (at positions beyond the upper end Pf of the printing paper P), an image can be recorded on the upper end of the printing paper P, Is not possible. That is, even when the printing paper P is sent more than the original feeding amount, as shown by a dashed line in FIG. 9, when the extra feeding amount is less than two rasters, the printing paper P There is no margin at the top of the file. The CPU 41 performs printing in an area (extended area) exceeding the upper end Pf of the printing paper P in this manner. That is, CPU
Reference numeral 41 corresponds to an "end printing unit" in the claims.

On the contrary, it is conceivable that the printing paper P is fed less than the original feeding amount for some reason. In such a case, there is no printing paper at the position where the printing paper should be, and the ink droplet Ip lands on the lower structure. However, as shown in FIG. 7, in the present embodiment, two rasters from the assumed upper end position of the paper are recorded by nozzles # 1 and # 2. Below these nozzles, a downstream groove 26 is provided.
r is provided, and if the ink droplet Ip is temporarily
Even if the ink droplet Ip does not land, the ink droplet Ip falls into the downstream groove 26r and is absorbed by the absorbing member 27r. Therefore, the ink droplets Ip do not land on the upper surface of the platen 26 and do not stain the printing paper later. That is, in the present embodiment, the printing paper P
Is higher than the assumed upper end position,
When the amount of deviation from the assumed upper end position is 2 rasters or less, the ink droplet Ip does not land on the upper surface of the platen 26 and does not stain the printing paper P later.

As described above, at the time of sub-scanning, the upper end Pf of the printing paper P is located above the opening of the downstream groove 26r, and the upper end Pf is located upstream of the nozzle at the downstream end in the sub-scanning direction. It is the CPU 41 that sets the position in the sub-scanning direction of the printing paper P so as to be at a certain position. That is, the CPU 41 corresponds to an “upper end positioning portion” in the claims.

The printing paper P is supplied to the upstream paper feed roller 25.
a and 25b and the downstream side paper feed rollers 25c and 25d are preferably held by two rollers and fed in the sub-scanning direction. This is because the sub-scan feed can be performed more accurately than the case where the sheet is held by only one roller and the sub-scan feed is performed. However, when printing the upper end Pf of the printing paper, the printing paper P is transferred to the upstream paper feed rollers 25a, 25a.
5b, and is fed in the sub-scanning direction. In the present 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 rasters on which nozzles on the print head 28 can record dots. (See FIGS. 7 and 9). Therefore, as shown in FIG.
Until f is held by the downstream paper feed rollers 25c and 25d, that is, while the printing paper is fed by the distance of L31, the sub-scan feed is performed only by the upstream paper feed rollers 25a and 25b, and printing is executed. Is done. In this embodiment, the sub-scan feed is performed only by the upstream paper feed rollers 25a and 25b, and the section in which printing is performed is relatively short, so that the print result has high image quality. Note that the present invention is not limited to the above-described embodiment, and the above-described effect can be obtained if the nozzle near the downstream end in the sub-scanning direction is used to print the vicinity of the upper end Pf of the printing paper. And, in particular,
Upstream sub-scanning drive section (upstream paper feed rollers 25a, 25
This is effective when the feeding accuracy of b) is relatively low.

Further, when printing the upper end portion, the printing paper P is supported at two places: the upstream 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 unlikely to be bent downward on the downstream groove 26r. Therefore, there is little possibility that the quality of the print result of the upper end portion is deteriorated due to the bending of the printing paper.

(Ii) Top feed of comparative example: FIG. 10 shows the print head 28 and the printing paper P at the start of printing in the comparative example.
It is a side view which shows the relationship. As shown in FIG. 10, even when the upper end portion of the printing paper P is printed in the upstream groove 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 print paper is fed (see FIG. 10) from the start of printing on the upper end portion of the print paper until the upper end of the print paper is held by the downstream paper feed rollers 25c and 25d.
) Is longer than that of the embodiment (L31 in FIG. 7). That is, the section in which the sub-scan feed is performed only by the upstream paper feed rollers 25a and 25b and printing is performed is relatively long. For this reason, the quality of the printing result is lower than that of the embodiment.

When printing the upper end portion, the printing paper P is held only by the upstream paper feed rollers 25a and 25b. For this reason, the upper end portion of the printing paper P easily bends downward on the upstream groove 26f. Therefore,
When printing the upper end portion, there is a relatively high possibility that the quality of the print result is reduced.

(Iii) Lower end processing of the first embodiment: FIG.
FIG. 7 is an explanatory diagram showing how each raster is recorded by which nozzle in the lower end process. FIG.
In FIG. 1, the portion from the point at which the (n + 1) -th sub-scan feed is performed to the point at which the last (n + 17) -th sub-scan feed is performed is shown. In the present embodiment, as shown in FIG.
In the intermediate processing, the feeding of 5 dots, 2 dots, 3 dots, and 6 dots is repeated in that order in the sub-scanning up to the (n + 8) -th time, and then, in the lower end processing, the last 9 times, that is, the sub-scanning from the (n + 9) -th to the (n + 17) -th times Feed 1
This is done by dot by dot. As a result, each raster along the main scanning direction is recorded by two nozzles except for some rasters. In FIG. 11, a raster on which the nozzles on the print head 28 can record dots is described.
The numbers given in order from the bottom are described on the right side of the figure. Hereinafter, the same applies to the drawings for explaining the printing of dots in the lower end processing.

In FIG. 11, in the four rasters from the bottom, the nozzle # 8 passes only once in printing. Then, the fifth or more raster lines from the bottom can be recorded by two or more nozzles. Therefore, the printable area in the lower end portion of the printing paper is the area of the fifth or more rasters from the bottom.

Also, in FIG.
In the 0th raster or the like, three or more nozzles pass in the main scan during printing. With respect to such a raster in which three or more nozzles pass in printing, it is preferable to perform recording by nozzles passing on the raster in the intermediate processing as much as possible. This is because the print result can be expected to have high image quality as compared with the lower end process in which the regular feed is performed dot by dot.

In this embodiment, as in the case of the upper end, an image is recorded without a margin at the lower end. 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 more rasters (printable area) from the downstream end in the sub-scanning direction are used to print an image. Can be recorded. However, in consideration of a case where an error occurs in the feed amount during the sub-scan feed, the recording is performed on the printing paper from the seventh raster from the downstream end in the sub-scan direction. That is, in a state where the lower end of the printing paper is at the position of the seventh raster from the upstream end in the sub-scanning direction, the ink drops Ip are also ejected to the fifth and sixth rasters, and Perform a scan. Therefore, the assumed position of the lower end of the printing paper with respect to each raster at the end of printing is
As shown in FIG. 11, this is the position of the seventh raster from the downstream end in the sub-scanning direction.

FIG. 12 is a plan view showing the relationship between the upstream groove 26f and the printing paper P when printing the lower end Pr of the printing paper P. In FIG. 12, the nozzle group Nf of the portion of the print head 28 indicated by oblique lines is the portion where the nozzles # 7 and # 8 are located. An upstream groove 26f is provided below a portion through which the nozzles pass during main scanning, and when the lower end Pr of the printing paper P is located at a position indicated by a dashed line on the upstream groove 26f, Finish printing.

FIG. 13 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
The nozzle on the nozzle 8 is located at the position of the seventh raster from the downstream end in the sub-scanning direction among the rasters on which dots can be recorded (FIG. 1).
1). That is, the lower end of the printing paper P is located six rasters earlier than the nozzle of # 8. Therefore, in this state, if the printing of the lowermost line of the printable area and the second raster from the lowermost line (the sixth and fifth raster lines from the bottom in FIG. 11) is to be performed,
The ink droplets Ip ejected from the nozzles # 7 and # 8 fall directly into the upstream groove 26f.

Also, if the printing paper P is sent less than the original feeding amount for some reason,
Since the nozzles # 7 and # 8 are ejecting ink droplets Ip to the fifth and sixth rasters from the bottom (at a position exceeding the lower end Pr of the printing paper P), the lower end Pr of the printing paper P
The image can be recorded on the image without any margin. That is, as shown by the one-dot chain line in FIG. 13, when the insufficient feed amount is equal to or less than two rasters, no margin is formed at the lower end of the printing paper P. It is the CPU 41 that performs printing in an area (extended area) exceeding the lower end Pr of the printing paper P in this manner. That is, the CPU 41 corresponds to an “edge printing unit” in the claims.

The two rasters (the seventh and eighth rasters from the bottom in FIG. 11) above the assumed upper end position of the paper are recorded by nozzles # 7 and # 8. Therefore, even if the printing paper P is sent more than the original feed amount for some reason, the ejected ink droplets Ip may fall into the upstream groove 26f and land on the upper surface of the platen 26. Absent.

As described above, at the time of sub-scanning, the lower end Pr of the printing paper P is located above the opening of the upstream groove 26f, and the lower end Pr is located downstream from the nozzle at the upstream end in the sub-scanning direction. It is the CPU 41 that sets the position in the sub-scanning direction of the printing paper P so as to be at a certain position. That is, the CPU 41 corresponds to a “lower end positioning portion” in the claims.

In this embodiment, the print head 2
At the position of the seventh raster from the downstream end in the sub-scanning direction among the rasters on which the nozzles on dot 8 can record dots (that is, the position two rasters before nozzle # 7 in FIG. 13),
The last raster on the printing paper is recorded in a state where the lower end Pr of the printing paper is located, and printing is completed (see FIG. 11). Therefore, the lower end Pr of the printing paper P is
5a and 25b to the position shown in FIG.
While the printing paper P is fed by a distance of 41, the sub-scan feed is performed only by the downstream paper feed rollers 25c and 25d,
Printing is executed. In this embodiment, the sub-scan feed is performed only by the downstream paper feed rollers 25c and 25d, and the section in which printing is performed is relatively short, so that the print result has high image quality. In particular, the downstream paper feed roller 25d is a gear-shaped roller, and the downstream paper feed rollers 25c and 25d.
The combination of d has lower feeding accuracy than the upstream paper feeding rollers 25a and 25b. Therefore, the fact that the sub-scan feed is performed only by the downstream paper feed rollers 25c and 25d and the section in which printing is performed is relatively short is very effective in improving the quality of the print result. Note that the present invention is not limited to the above-described embodiment, and the above-described effect can be obtained if the nozzle near the upstream end in the sub-scanning direction is used to print the vicinity of the lower end Pr of the printing paper. This is particularly effective when the feeding accuracy of the downstream sub-scanning drive units (downstream paper feed rollers 25c and 25d) is relatively low.

Further, when printing the lower end portion, the printing paper P is supported at two places: the downstream paper feed rollers 25 c and 25 d and the upper surface of the platen 26. Therefore, the lower end portion of the printing paper P is relatively unlikely to be bent downward on the upstream-side groove portion 26f. Therefore, there is little possibility that the quality of the print result of the upper end portion is deteriorated due to the bending of the printing paper.

(Iv) Lower end feed of comparative example: 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 in the comparative example.
As shown in FIG. 14, even when the lower end portion of the printing paper P is printed in the downstream groove 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. 14, the distance L42 to which the printing paper is fed from when the lower end of the printing paper leaves the upstream paper feed rollers 25a and 25b to when printing is completed is the case of the embodiment ( It is longer than L41) in FIG. That is, the sub-scan feed is performed only by the downstream paper feed rollers 25c and 25d having relatively low feed accuracy, and the section in which printing is performed is long. For this reason, the quality of the printing result is lower than that of the embodiment.

When printing the lower end portion, the print paper P is held only by the downstream paper feed rollers 25c and 25d. For this reason, the lower end portion of the printing paper P is easily bent downward on the downstream groove 26r. Therefore,
When printing the lower end portion, there is a relatively high possibility that the quality of the print result is reduced.

C. Second Embodiment: FIG. 15 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, the case where the upper end processing and the lower end processing are performed in a printing apparatus in which one nozzle row has 11 nozzles will be described. In the printing apparatus used here, the downstream groove 26
ra is provided at a position facing the nozzles # 1 to # 3 in the sub-scanning direction. The upstream groove 26fa
Are provided at positions facing the nozzles # 9 to # 11. The other points are the same as those of the printing apparatus described above. In the second embodiment, overlap printing is not performed. That is, each raster is recorded by one nozzle in one main scan.

(1) Upper end processing of the second embodiment: FIGS. 16 and 17 are explanatory diagrams showing how each raster is recorded by which nozzle in the upper end processing of the second embodiment. . 16 and 17 show the manner in which the head prints a raster, divided into upper and lower parts. The lower part of FIG. 16 is connected to the upper part of FIG. Note that the 38th to 42nd rasters from the top are duplicated in FIGS. 16 and 17.

As shown in FIG. 16, in the upper end processing of the second embodiment, the sub-scan feed of three dots is repeated 11 times. In the upper end processing, the # of the print head 28a is
Nozzles other than nozzles # 1 to # 3 are not used. In addition,
In the figure, nozzles surrounded by thick frames are nozzles that record dots on a raster.

Thereafter, instead of performing the intermediate processing immediately, the "transfer processing" is performed before the intermediate processing is performed. In this transition processing, the sub-scan feed of three dots is performed four times as in the upper end processing. In the transfer process, all nozzles # 1 to # 11 are used. Thereafter, as shown in FIG. 17, the process proceeds to the intermediate processing, and the regular feeding of 11 dots is repeated.

In FIG. 16, the nozzles of the second, third, and sixth rasters from the uppermost row do not pass in the main scan during printing. Therefore, for the sixth raster from the top, pixels cannot be printed consecutively on adjacent rasters. In the present embodiment, these six rasters are “non-printable areas”. Also, for a raster such as the thirteenth or sixteenth raster from the top, which passes through two or more nozzles, only the nozzle that last passes through the raster records dots.

In the second embodiment, among the rasters on which the nozzles on the print head 28 can record dots, an image is recorded using the rasters (printable area) that are the seventh and subsequent rasters from the upstream end in the sub-scanning direction. can do. 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 is started not when the upper end of the printing paper P is at the seventh position from the upstream end in the sub-scanning direction but at the 23rd raster position. . That is, the assumed position of the upper end of the printing paper P for each raster at the start of printing is
As shown in FIG. 16, this 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 upper end position of the printing paper P. For this reason, even if an error occurs in the feeding of the printing paper P and the printing paper P is sent extra, if the error is within 16 rasters,
An image can be formed without a margin up to the upper end of the printing paper P.

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 nozzles # 1 to # 4.
Recorded only in # 3. A downstream groove 26ra is provided below the nozzles # 1 to # 3. Therefore, the expected position of the upper end of the printing paper P is exceeded (that is,
The above-mentioned 16 set in a range where no printing paper exists)
Even if ink droplets are ejected on the raster, the platen 26a
No ink droplets land on the top. 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 has not been fed to the expected position due to an error in the feeding of the printing paper P, If the error is within 20 rasters, ink droplets will not land on the platen 26a.

(2) Lower end processing of the second embodiment: FIGS. 18 and 19 are explanatory diagrams showing how each raster is recorded by which nozzle in the lower end processing of the second embodiment. . FIG. 18 shows the (n + 1) th and subsequent sub-scan feeds. FIGS. 18 and 19 show the manner in which the head prints a raster, divided into upper and lower parts. The lower part of FIG. 18 is connected to the upper part of FIG. Note that the 45th to 40th rasters from the bottom are duplicated in FIGS. 18 and 19.

In the present embodiment, as shown in FIGS. 18 and 19, in the intermediate processing, the regular scanning of 11 dots is repeated in the (n + 1) -th to (n + 3) -th sub-scanning feeds, and then the 3-dot feeding is performed in the transition processing. Repeat 4 times.
Then, in the lower end processing, the nozzles # 9 to # 1
3 dots are fed using only 1.

In the second embodiment, as shown in FIG. 19, among the rasters on which the nozzles on the print head 28 can record dots, the seventh or more lower rasters (printable area) are used. Images can be recorded. But,
In the second embodiment, an image is recorded using the eighth or more rasters from the bottom. That is, the eighth or more rasters from the bottom in FIG. 19 are print areas, and image data is set for those rasters.

In FIG. 19, the 13th and 16th rasters from the bottom are 2nd rasters in the main scan during printing.
More than one nozzle passes. For such a raster in which two or more nozzles pass in printing, nozzles that pass on the raster first record dots.

In the second embodiment, an image can be recorded using the eighth or more rasters from the downstream end in the sub-scanning direction among the rasters on which the nozzles on the print head 28 can record dots. Therefore, the image data D used for printing
Sets up to this 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 eighth position from the downstream end in the sub-scanning direction. . That is, the assumed position of the lower end of the printing paper P with respect to each raster at the end of printing is the position of the 38th raster from the downstream end in the sub-scanning direction, as shown in FIG. Therefore, the second
In the embodiment, the image data D is provided for 30 rasters beyond the assumed lower end position of the printing paper P. For this reason, even if an error occurs in the feeding of the printing paper P and the printing paper P is not sent to the expected position, if the error is within 30 rasters, an image can be formed with no blank space to the lower end.

In the second embodiment, 30 rasters set beyond the assumed lower end position of the printing paper P and 20 rasters upstream from the lower end position are only nozzles # 9 to # 11. Be recorded. And nozzle # 9 ~
An upstream groove 26fa is provided below # 11. Therefore, even if an ink droplet is ejected to a raster set beyond the assumed position of the lower end of the printing paper P (that is, in a range where the printing paper does not exist), the ink droplet lands on the platen 26a. Nothing. Further, if an error occurs in the feeding of the printing paper P and the printing paper P is sent extra, even if ink droplets are ejected to a raster assigned to the lower end of the printing paper P, the feeding Error is 2
If it is within 0 rasters, ink droplets will not land on the platen 26a.

When printing the lower end of the printing paper P, the printing paper P is fed a longer distance than when printing the upper end of the printing paper P. Therefore, when recording the lower end of the printing paper P, there is a high possibility that the error in the position of the printing paper P is larger than when recording the upper end of the printing paper P. The downstream paper feed roller 25d is a gear-shaped roller, and the downstream paper feed roller 2d
The combination of 5c and 25d is the upstream paper feed roller 25.
The feed accuracy is lower than that of the feed a and 25b. Therefore, from this point, there is a high possibility that the error at the time of recording the lower end side is larger than the error of the position of the printing paper P at the time of recording the upper end side. Therefore, as in the second embodiment, the nozzles (# 9 to # 1) on the upstream groove 26fa at the lower end of the printing paper P are used.
1) The number of rasters recorded only by
At the upper end of the nozzle on the downstream groove 26ra (# 1
It is preferable that the number of rasters is set to be larger than the number of rasters recorded only by # 3). Then, in the image data D, the number of rasters set beyond the lower end of the printing paper P is
It is preferable to set more than the number of rasters set beyond the upper end of the printing paper P.

D. Third Embodiment FIG. 20 is a side view showing the relationship between the print head 28b, the upstream groove 26fb, and the downstream groove 26rb in the third embodiment. Here, a case where the upper end processing and the lower end processing are performed in a printing apparatus in which one nozzle row has 48 nozzles will be described. In the printing apparatus used here, the downstream groove 26
rb is provided at a position facing the nozzles # 1 to # 12 in the sub-scanning direction. The upstream groove 26fb
Are provided at positions facing the nozzles # 37 to # 48. The other points are the same as those of the printing apparatus described above.

FIG. 21 is an explanatory diagram showing the arrangement of the ink jet nozzles Nz in the ink discharge heads 61b to 66b in the third embodiment. In the third embodiment,
The pitch of each nozzle and the pitch of the raster are the same. Therefore, the print head 28b can record dots on adjacent raster lines in one main scan. In FIG. 21, a range facing the downstream groove 26rb on the platen 26b is denoted by Rr, and a range facing the upstream groove 26fb is denoted by Rf. Nozzles in the range Rr are nozzles # 1 to # 12, and nozzles in the range Rf are # 37 to # 48. In the third embodiment, overlap printing is performed using the print head 28b.

(1) Upper end processing of the third embodiment: FIGS. 22 and 23 are explanatory diagrams showing how each raster is recorded by which nozzle in the upper end processing of the third embodiment. . The lower part of FIG. 22 is connected to the upper part of FIG. Note that the 66th to 74th rasters from the top are redundantly described.

As shown in FIG. 22, in the upper end processing of the third embodiment, the sub-scan feed of 6 dots is repeated 10 times. This upper end processing is printing in the “first recording mode” described in the claims. In this upper end processing, nozzles other than the nozzles # 1 to # 12 of the print head 28b are not used. In the figure, nozzles surrounded by thick frames are nozzles that record dots on a raster. The nozzle used in the upper end processing is the nozzle group N1 in FIG.
Nozzle.

Thereafter, a “transfer process” is performed. In this transition process, 6-dot sub-scan feed is performed twice as in the upper end process. In the shift processing, after the first feed, # 1 to # 12 as in the case of the upper end processing
Dots are recorded by the nozzles. After the second feed, nozzles # 1 to # 30 are used. Thereafter, as shown in FIG. 23, the process proceeds to the intermediate process, and the regular feeding of 24 dots is repeated. In the intermediate processing,
All nozzles of # 48 are used. This intermediate processing is printing in the “second recording mode” described in the claims. The nozzles used after the second feeding in the transition process are the nozzles shown as the nozzle group N2 in FIG. The nozzles used in the intermediate processing are the nozzles shown as the nozzle group N3 in FIG.

In FIG. 22, overlap printing cannot be performed for the rasters from the uppermost row to the sixth raster row because the nozzles pass only once in the main scan during printing. In the present embodiment, these six rasters are “non-printable areas”. In addition, for a raster that passes through two or more nozzles, such as the 13th and subsequent rasters from the top, only the nozzle that passes through the last raster and the nozzle that passes through the raster immediately before that record dots. .

In the third embodiment, the image data D used for printing is set from the uppermost end of the printable area, 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 37th raster position from the upstream end in the sub-scanning direction. The position is shown as an assumed position of the upper end of the printing paper P in FIG. That is, in the third embodiment, the position 3
Image data D is provided for six rasters. For this reason,
Even if an error occurs in the feeding of the printing paper P and the printing paper P is sent excessively, an image can be formed without a margin up to the upper end of the printing paper P if the error is within 36 rasters.

In the third embodiment, the 36 rasters set beyond the assumed upper end position of the printing paper P and the 42 rasters from the upper end position correspond to the nozzle # 1 on the downstream groove 26rb. ~ # 12 only. Therefore, even if ink droplets are ejected to the 36 rasters set above the assumed position of the upper end of the printing paper P (that is, in a range where no printing paper exists), the platen 2
No ink droplets land on 6a. Further, even if ink droplets are ejected to a raster assigned to the upper end of the printing paper P in a state where an error has occurred in the feeding of the printing paper P and the printing paper P has not been sent to the expected position,
If the feed error is within 42 rasters, the platen 26
No ink droplets land on b.

(2) Lower end processing of the third embodiment: FIGS. 24 and 25 are explanatory diagrams showing how each raster is recorded by which nozzle in the lower end processing of the third embodiment. . The lower part of FIG. 24 is connected to the upper part of FIG.

In the present embodiment, as shown in FIG. 24, after the regular feeding of 24 dots is repeated in the intermediate processing,
In the transition process, six dots are fed once. The nozzles used after the feed are # 19 to # 48. Thereafter, in the lower end processing, six dots are fed using only the nozzles # 37 to # 48. It should be noted that the nozzles used after the transfer of the transfer process are the nozzle group N in FIG.
Nozzle designated as 4. The nozzles used in the lower end processing are the nozzles shown as the nozzle group N5 in FIG.

In the third embodiment, as shown in FIG. 25, among the rasters on which the nozzles on the print head 28 can record dots, the seventh or more rasters from the bottom (printable area) are used. Images can be recorded. But,
In the third embodiment, an image is recorded using the ninth or more rasters from the bottom. That is, the ninth or more rasters from the bottom in FIG. 25 are print areas, and image data is set for those rasters.

In FIG. 25, two or more nozzles pass through the thirteenth or more raster lines from the bottom in the main scan during printing. For such a raster in which two or more nozzles pass in printing, the nozzle that first passes over the raster and the nozzle that subsequently passes through the raster record dots.

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 is performed on the printing paper P.
Is terminated when the lower end of is located at the position of the 49th raster, not at the ninth position from the downstream end in the sub-scanning direction. FIG. 25 shows the assumed position of the lower end of the printing paper P with respect to each raster at the end of printing. Therefore, in the third embodiment, the position 4
Image data D is provided for 0 rasters. For this reason, even if an error occurs in the feeding of the printing paper P and the printing paper P is not sent to the expected position, if the error is within 40 rasters, it is possible to form an image with no blank space at the lower end.

In the third embodiment, the 40 rasters set beyond the assumed lower end position of the printing paper P and the 36 rasters upstream from the lower end position are the nozzles on the upstream groove 26fb. It is recorded only in # 37 to # 48. Therefore, even if ink droplets are ejected to a raster set beyond the assumed position of the lower end of the printing paper P (that is, in a range where no printing paper exists), the platen 26b
No ink droplets land on the top. Further, if an error occurs in the feeding of the printing paper P and the printing paper P is sent in excess, even if ink droplets are ejected to the raster assigned to the lower end of the printing paper P, the feeding of the printing paper P may be stopped. If the error is within 36 rasters, no ink droplet will land on the platen 26a.

In the third embodiment, the printing paper P
At the lower end of the nozzle on the upstream groove 26fb (# 3
The number of rasters recorded by only the nozzles (# 1 to # 12) on the downstream groove 26rb at the upper end of the printing paper P is set to be larger than the number of rasters recorded only by the nozzles 7 to # 48). I have. Then, in the image data D, the number of rasters set beyond the lower end of the printing paper P is
The number is set to be larger than the number of rasters set beyond the upper end of the printing paper P.

E. Aspects having side grooves: In the above description, as shown in FIGS. 9 and 13, in the printer 22 having the upstream grooves 26f and the downstream grooves 26r in the platen 26, the printing paper P is set beyond the upper and lower ends. The aspect in which printing is performed based on the image data D (see FIG. 8) has been described. Here, the upstream groove 26f, the downstream groove 2
In the printer 22n having the left groove 26na and the right groove 26nb on the platen in addition to 6r, image data Dn set beyond the upper and lower ends and the left and right ends of the printing paper P.
The printing mode will be described based on the above.

FIG. 26 is a plan view showing the relationship between image data Dn and printing paper P. In FIG. 26, the image data D
n is set not only to the upper end Pf and the lower end Pr of the printing paper P but also to the outside of the printing paper P beyond the left end Pa and the right end Pb. As a result, in the present embodiment, the relationship between the size of the image data Dn and the printing paper P, and the relationship between the assumed position of the image data Dn at the time of printing and the arrangement of the printing paper P are as shown in FIG.
It becomes as shown in. The width of the image that can be recorded by the image data Dn (the width of the extended area) has a width that exceeds the left and right ends of the printing paper P, and exceeds the interval between the outer side walls of the left groove 26na and the right groove 26nb. With no width. Since the left and right names of the left end Pa and the right end Pb correspond to the left and right names of the printer 22, the actual left and right and left end Pa,
The name of the right end Pb is reversed.

FIG. 27 shows the platen 26 of the printer 22n.
It is a top view which shows the periphery of n. This printer 22n
Guides 29a and 29 for guiding the printing paper P to maintain a predetermined position in the main scanning direction during the sub-scanning of the printing paper P.
b. The platen 26n has an upstream groove 26f and a downstream groove 2 similarly to the platen 26 of FIG.
6r is provided. Furthermore, the platen 26n has
A left-side groove 26na extending in the sub-scanning direction so as to connect both ends of the upstream-side groove 26f and the downstream-side groove 26r.
And a right-side groove 26nb. Left groove 26
The na and the right groove portion 26nb are provided in a range in the sub-scanning direction longer than the landing range of the ink droplet from the nozzle row on the print head. The left groove portion 26na and the right groove portion 26nb are provided such that the interval between the respective center lines (in the main scanning direction) is equal to the width of the printing paper P in the main scanning direction. Another configuration is the printer 22 described above.
Is the same as

The left groove 26na and the right groove 26n
b, 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 located on the opening of the left groove 26na; What is necessary is just to provide so that the other side end part Pb may be located on the opening of 26 g of right side groove parts. Therefore, as described above, when the printing paper P is at a fixed position, the left and right grooves 26na and 26nb have a side edge on the center line of the left and right grooves 26na and 26nb. May be provided so as to be located inside or outside the center line of the left groove portion 26na and the right groove portion 26nb.

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

The printing paper P is fed to the upstream paper feed roller 25.
When the sub-scan feed is being performed by a, 25b and the downstream paper feed rollers 25c, 25d, the paper passes over the openings of the upstream groove 26f and the downstream groove 26r.
On the platen 26n, the printing paper P has the left end Pa located on the left groove 26na and the right end Pb
Are positioned on the right groove 26nb so that the guide 29
Positions are made in the main scanning direction by a and 29b. Therefore, at the time of the sub-scan feed, the feed is performed while maintaining the positions where the both side ends of the printing paper P are above the openings of the left groove 26na and the right groove 26nb, respectively.

Also in the embodiment shown in FIG. 27, the sub-scan feed of the upper end processing and the lower end processing is performed according to the above-described B.I. The first embodiment (see FIGS. 6, 7, 9, and 11 to 13), C.I. Second embodiment (see FIGS. 15 to 19), D.E. Feeding of the third embodiment (see FIGS. 20 to 25) and the like can be performed. Therefore, hereinafter, the side edge P of the printing paper P will be described.
The printing of a and Pb will be described.

FIG. 28 is an explanatory diagram showing the printing of the left and right end portions of the printing paper P. In the mode of FIG. 27, printing is performed so that no margin is provided at the left and right edges of the printing paper P throughout the 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 sent to one end at a position where all the nozzles are located beyond the end of the printing paper P and located outside the printing paper P, and the other end is also moved. All the nozzles are fed to the position beyond the other end of the printing paper P and located outside the printing paper P. Then, not only when the nozzle Nz is on the printing paper P, but also when the nozzle Nz is located beyond the edge of the printing paper P and on the left groove 26na or the right groove 26nb, The ink droplet is ejected from the nozzle Nz according to Dn. Note that the image area (extended area) of the image data Dn has a width exceeding the left and right ends of the printing paper P, and the left groove 26
na and a width not exceeding the interval between the outer side walls of the right groove 26nb. For this reason, even when the nozzle is outside the printing paper P and on the left groove 26na or the right groove 26nb, the ink droplet can be ejected according to the image data Dn.

By performing such printing, even if the printing paper P slightly shifts in the main scanning direction, it is possible to form an image without creating a margin on both right and left ends of the printing paper P. Since the nozzles that print both side edges of the printing paper are nozzles located on the left groove 26na or the right groove 26nb, even when the ink drops come off the printing paper P, the ink drops remain in the center of the platen 26. 26c without landing on the left groove 26na or the right groove 2
Lands at 6nb. Therefore, the central portion 26 of the platen 26
The printing paper P is not stained by the ink droplets that have landed on c.

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

E1. Modified Example 1 In the first embodiment, the upper end processing and the lower end processing perform a regular feed of one dot each,
In the embodiment, the regular feed of 3 dots is performed, and in the third embodiment, 6 dots are performed. However, the feeding of the upper end processing and the lower end processing is not limited to this, and regular feeding of 2 dots, 4 dots, and 5 dots can be performed according to 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-scan feed in the upper end process, the more the nozzle on the downstream side in the sub-scan direction can record the upper end of the printing paper. Therefore, the downstream groove can be made narrower, and the upper surface of the platen supporting the printing paper can be made wider. Similarly, the smaller the feed amount of the sub-scan feed in the lower end process, the higher the nozzle on the upstream side can record the upper end of the printing paper. for that reason,
The groove on the upstream side can be made narrower, and the upper surface of the platen supporting the printing paper can be made wider.

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, 5 dots, 3 dots, 2 dots, and 6 dots may be fed. Further, other combinations of the feed amounts may be adopted in accordance with the number of nozzles, the nozzle pitch, and the like, and regular feed of other feed amounts may be performed. That is, 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 end processing, any sub-scan feed may be performed.

E2. Modified Example 2: In the above embodiment, the image set beyond the edge of the printing paper is two rasters on both the upper end side and the lower end side in the first embodiment, and the upper end side is 16 rasters in the second embodiment. And the lower end side was 30 rasters. In the third embodiment, the upper end side has 30 rasters and the lower end side has 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 set to a half of the width of the downstream groove 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 set to a half of the width of the upstream groove 26f.
That is, the width of the part of the image data 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 may be smaller than the width of the upstream groove 26f on the lower end side. It should just be smaller than the width of.
By doing so, even when the edge of the printing paper P is not at the expected position, the ink droplet Ip for recording the image set beyond the printing paper P may land on the upper surface of the platen 26. Absent. However, if the width of the groove portion is set to も, the same amount of deviation can be permitted both when the printing paper P is shifted to the upstream side and when it is shifted to the downstream side.

Similarly, for the left and right side edges, the width of the portion of the image data set beyond the edge of the printing paper to the outside of the printing paper is smaller than the width of the left groove 26na and the right groove 26nb. I just need. If the width of the groove is set to も, the same amount of deviation can be tolerated both when the printing paper P shifts to the upstream side and when it shifts to the downstream side.

E3. 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 as necessary. Further, the printing apparatus of the present embodiment includes the upstream groove portion 26f and the downstream groove portion 26r on the platen 26 on the upstream side and the downstream side in the sub-scanning direction, respectively, but may include only one of them. .

E4. Modification 4: In the above embodiment, a part of the configuration realized by hardware may be replaced by software, and conversely, a part of the configuration realized by software may be replaced by hardware. You may. For example, the CPU 41
A part of the functions of FIG. 4 may be executed by the host computer 90.

A computer program for realizing such functions 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 the computer program from the recording medium and transfers it to an internal storage device or an external storage device. Alternatively, from the program supply device to the host computer 90 via a communication path.
May be supplied with a computer program. When implementing the functions of a computer program,
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.

In this specification, the host computer 90 is a concept including a hardware device and an operation system, and means a hardware device that operates under the control of the operation system. The computer program is executed by such a host computer 9.
0 implements the functions of the above-described units. Some of the functions described above may be realized by an operation system instead of the application program.

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 may be various internal memories such as a RAM and a ROM. It also includes a device and an external storage device fixed to the computer such as a hard disk.

[Brief description of the drawings]

FIG. 1 is an enlarged plan view showing the structure of a part of the left side of a platen of an inkjet printer according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a configuration of an image processing apparatus and a printing apparatus according to an embodiment of the invention.

FIG. 3 is a block diagram illustrating a software configuration of the printing apparatus.

FIG. 4 is a diagram illustrating a configuration of a mechanical part of the printing apparatus.

FIG. 5 is a plan view showing an example of an arrangement of nozzle units for each color in the print head unit 60.

FIG. 6 is a plan view showing the periphery of a platen 26;

FIG. 7 is an explanatory diagram showing how each raster is recorded by which nozzle near the upper end (front end) of a printing sheet.

FIG. 8 is a plan view showing the relationship between image data D and printing paper P.

FIG. 9 is a side view showing the relationship between the print head and the printing paper P at the start of printing.

FIG. 10 shows a print head 28 at the start of printing in a comparative example.
FIG. 4 is a side view showing a relationship between the printing paper P and the printing paper P.

FIG. 11 is an explanatory diagram showing how each raster is recorded by which nozzle in the lower end process.

FIG. 12 is a plan view showing the relationship between the upstream groove 26f and the printing paper P when printing the lower end Pr of the printing paper P.

FIG. 13 is a side view showing the relationship between the print head and the printing paper P when printing the lowermost end of the printing paper.

FIG. 14 is a side view showing the relationship between the print head and the printing paper P when printing the lowermost end of the printing paper in the comparative example.

FIG. 15 is a side view showing a relationship between a print head 28a, an upstream groove 26fa, and a downstream groove 26ra in the second embodiment.

FIG. 16 is an explanatory diagram showing how each raster is recorded by which nozzle in the upper end process of the second embodiment.

FIG. 17 is an explanatory diagram showing how each raster is recorded by which nozzle in the upper end process of the second embodiment.

FIG. 18 is an explanatory diagram showing how each raster is recorded by which nozzle in the lower end process of the second embodiment.

FIG. 19 is an explanatory diagram showing how each raster is recorded by which nozzle in the lower end process of the second embodiment.

FIG. 20 is a side view showing the relationship between the print head 28b, the upstream groove 26fb, and the downstream groove 26rb in the third embodiment.

FIG. 21 is an ink ejection head 61 according to a third embodiment.
Explanatory drawing which shows arrangement | positioning of the inkjet nozzle Nz in b-66b.

FIG. 22 is an explanatory diagram showing how each raster is recorded by which nozzle in the upper end process of the third embodiment.

FIG. 23 is an explanatory diagram showing how each raster is recorded by which nozzle in the upper end process of the third embodiment.

FIG. 24 is an explanatory diagram showing how each raster is recorded by which nozzle in the lower end process of the third embodiment.

FIG. 25 is an explanatory diagram showing how each raster is recorded by which nozzle in the lower end process of the third embodiment.

FIG. 26 is a plan view showing the relationship between image data Dn and printing paper P.

FIG. 27 is a plan view showing the periphery of a platen 26n of the printer 22n.

FIG. 28 is an explanatory diagram showing printing on left and right ends of printing paper P.

FIG. 29 is a side view showing the periphery of a print head of a conventional printer.

[Explanation of symbols]

DESCRIPTION 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 Rollers 25p, 25q Upstream paper feed rollers 25r, 25s Downstream paper feed rollers 26, 26a, 26b, 26n, 26o Platen 26c Central portions 26f, 26fa, 26fb Upstream groove 26na Left groove 26nb Right Grooves 26r, 26ra, 26rb Downstream grooves 27, 27f, 27r Absorbing members 28, 28a, 28b, 28o Printing heads 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 A… Arrow D, Dn… Image data DT… Dot formation pattern table F ... Flexible disk Ip ... Ink droplet L31 ... Distance printed and printed by only the upstream paper feed roller L41 ... Distance printed and printed by only the downstream paper feed roller L32 ... Only by the upstream paper feed roller Distance for sub-scan feed and printing L42 ... Distance for sub-scan feeding and printing only by downstream paper feed roller LUT ... Color correction table MS ... Arrow N1 ... Nozzle group used in upper end processing N2 ... Used in transition processing Nozzle group used in intermediate processing N4 ... Nozzle group used in transition processing N5 ... Nozzle group used in lower end processing Nf ... Upstream nozzle group Nr ... Downstream nozzle group Nz ... Inkjet Nozzle ORG: Original color image data P: Printing paper PD: Printing data PE: Piezo element PNT: Public Telephone line Pa: left end (part) Pb: right end (part) Pf: upper end (part) Pr: lower end (part) R26: range in which the center of the platen is provided Rf: upstream groove part is provided Range Rr: Range where the downstream groove is provided SS: Arrow SV: Server k: Nozzle pitch

Claims (10)

[Claims] 1. A dot recording apparatus for recording 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, wherein at least one of the dot recording head and the printing medium is provided. While at least one of the plurality of dot forming elements is driven to drive one of the plurality of dot forming elements to form a dot,
A dot recording method for performing sub-scanning by driving the print medium in a direction intersecting with the main scanning direction during the main scanning, wherein the dot recording apparatus is configured to perform the main scanning in at least a part of a path of the main scanning. It is provided extending in the main scanning direction so as to face a dot forming element, and is provided at a position facing a dot forming element located at least at an upstream end in the sub-scanning direction among the plurality of dot forming elements. A platen having an upstream groove portion and a downstream groove portion provided at a position facing at least a dot forming element located at a downstream end in the sub-scanning direction among the plurality of dot forming elements. The dot recording method includes: (a) storing image data for recording an image in an extended area having a length exceeding at least upper and lower ends of the print medium; Preparing a non-print data, (b) on the basis of the print data, dot recording method comprising the steps of ejecting ink droplets onto the expanded area. 2. The dot recording method according to claim 1, wherein in the step (b), (b1) the printing medium is supported by the platen when an ink droplet is ejected to an upper end of the printing medium. And a position where the upper end of the print medium is above the opening of the downstream groove portion and the upper end is upstream of the dot forming element at the downstream end in the sub-scanning direction in the sub-scanning direction. Setting the position of the print medium in the sub-scanning direction so that the print medium is located in the sub-scanning direction; (b2) when ejecting ink droplets to the lower end of the print medium, the print medium is supported by the platen; and The lower end of the print medium is above the opening of the upstream groove, and the lower end of the print medium is downstream of the dot forming element at the upstream end in the sub-scan direction in the sub-scan direction. The printing medium so as to come into position Dot recording method comprising the steps of setting a position of the sub-scan. 3. The dot recording method according to claim 1, wherein the platen further comprises:
And a pair of side grooves provided at least in a range including a landing range of ink droplets from the plurality of dot forming elements and provided at intervals substantially equal to the width of the print medium; And (a1) for recording an image in the extended area having a width exceeding the left and right ends of the printing medium and having a width not exceeding the interval between the outer side walls of the pair of side grooves. A step of preparing print data including the image data. 4. The dot recording method according to claim 3, wherein in the step (b), (b3) the printing medium is supported by the platen, and both side edges of the printing medium are respectively positioned on the side. A dot recording method, comprising: setting a position of the print medium in the main scanning direction so as to maintain a position on the opening of the groove. 5. The dot recording method according to claim 1, wherein in the step (a), (a2) information of a dot recording state in each pixel in the extension area is stored in the dot recording method. A dot recording method, comprising a step of preparing the print data to be provided as image data. 6. A dot recording apparatus for recording dots on a surface of a printing medium using a dot recording head provided with a plurality of dot forming elements for discharging ink droplets, wherein the dot recording head and the printing medium A main scanning drive unit that performs main scanning by driving at least one of the above, and a head driving unit that drives at least a part of the plurality of dot forming elements to form dots during the main scanning. A platen extending in the main scanning direction so as to face the dot forming element in at least a part of a path of the main scanning; and intersecting the printing medium with the main scanning direction between the main scanning. A sub-scanning drive unit that performs sub-scanning by driving in a direction, and a control unit that controls each of the units, wherein the platen has at least one of the plurality of dot forming elements. An upstream groove provided in the main scanning direction at a position facing a dot forming element positioned at an upstream end in the sub-scanning direction; and at least the sub-scanning of the plurality of dot forming elements. And a downstream groove portion provided in the main scanning direction so as to extend in a position facing the dot forming element located at the downstream end of the printing medium. A print data storage unit that stores print data including image data for recording an image in an extended area having a length exceeding the upper and lower ends; and an end that ejects ink droplets to the extended area based on the print data. And a printing unit. 7. The dot recording apparatus according to claim 6, wherein the control unit is further configured such that, when ejecting ink droplets to an upper end of the print medium, the print medium is supported by the platen; The upper end of the print medium is located above the opening of the downstream groove, and the upper end is located at a position upstream of the dot forming element at the downstream end in the sub-scanning direction in the sub-scanning direction. An upper end positioning unit that sets a position of the print medium in the sub-scanning direction; and when the ink medium is ejected to the lower end of the print medium, the print medium is supported by the platen; Is located above the opening of the upstream groove, and the lower end of the print medium is located at a position downstream of the dot forming element at the upstream end in the sub-scanning direction in the sub-scanning direction. To the printing medium A dot recording apparatus comprising: a lower end positioning unit that sets a position in the sub-scanning direction. 8. The dot recording apparatus according to claim 7, wherein the platen further comprises:
The dot recording device is provided at least in a range including a landing range of ink droplets from the plurality of dot forming elements, and has a pair of side groove portions provided at intervals substantially equal to the width of the print medium. Further, the print medium is supported by the platen, and the print medium is positioned in the main scanning direction so that both side edges of the print medium are respectively located on the openings of the side grooves. The print data has a width that exceeds the left and right ends of the print medium, and has a width that does not exceed the interval between the outer side walls of the pair of side grooves. A dot recording device including the image data for recording an image. 9. The dot recording apparatus according to claim 6, wherein the print data includes information on a dot recording state of each pixel in the extended area as the image data. Dot recording device. 10. A computer comprising a dot recording device for recording dots on the surface of a print medium using a dot recording head provided with a plurality of dot forming elements for ejecting ink droplets, the computer comprising the dot recording head and the printing While at least one of the media is driven to perform main scanning, at least a part of the plurality of dot forming elements is driven to form dots, and the printing medium is subjected to the main scanning during the main scanning. A computer-readable recording medium recording a computer program for performing sub-scanning by driving in a direction intersecting a direction, wherein the dot recording apparatus includes the dot forming element in at least a part of a path of the main scanning. And extending in the main scanning direction so as to face the at least one of the plurality of dot forming elements. An upstream groove portion provided at a position facing the dot forming element located at the upstream end in the direction of, and a dot forming element located at least at the downstream end in the sub-scanning direction among the plurality of dot forming elements. And a downstream groove provided at a position facing the recording medium.The recording medium is for recording an image in an extended area having a length exceeding at least the upper and lower ends of the printing medium. A computer-readable recording medium storing a computer program for causing the computer to realize a function of preparing print data including image data of the above, and a function of ejecting ink droplets to the extended area based on the image data. Possible recording medium.