Printing device and computer program

Abstract

To improve the image quality of a printed image.SOLUTION: A printing execution unit includes an opposite member that can be positioned opposite a printing surface of a printing medium on an upstream side of a plurality of nozzles of a print head in a conveying direction. A control device conveys the printing medium by a second amount of conveyance smaller than a first amount of conveyance after executing second partial printing an N number of times, then executes third partial printing an N number of times executed while the printing medium is positioned at a specific position where a predetermined position at an upstream end of the printing medium in the conveying direction is positioned opposite the opposite member, then conveys the printing medium, and then executes fourth partial printing an N number of times executed while the printing medium is not opposite the opposite member. The amount of conveyance of the printing medium of an (N-1) number of time between the N number of partial printings is determined such that the number of raster lines positioned on an upstream side in the conveying direction of the plurality of raster lines printable in the N number of second partial printings, among a plurality of raster lines printable in the N number of third partial printings is equal to or more than the number of raster lines printed in a first end region.SELECTED DRAWING: Figure 9

Description

[Technical field]

[0001] The present specification relates to a control device for a print execution unit that includes a print head having a plurality of nozzles and a transport unit that transports a print medium in a transport direction relative to the print head. [Background technology]

[0002] The printer disclosed in Patent Document 1, when printing in multiple pass processes, prints in two pass processes a portion of the area near the boundary of the band area printed in each pass process. This prevents banding from becoming noticeable near the boundary of the band area. This printer is equipped with a pressing member that presses the paper from the printing surface side, upstream of the multiple nozzles of the print head in the transport direction. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-153182 A Summary of the Invention [Problem to be solved by the invention]

[0004] This specification discloses a technique for improving the quality of an image printed by a print execution unit having an opposing member (for example, the above-mentioned pressing member) capable of facing the printing surface of a sheet of paper. [Means for solving the problem]

[0005] The technology disclosed in this specification can be realized in the following application examples.

[0006] [Application Example 1] A printing device comprising a print execution unit and a control device, the print execution unit comprising a transport unit which transports a print medium in a transport direction, a print head having a plurality of nozzles which eject ink of a specific color, the plurality of nozzles being positioned at different positions in the transport direction, and which ejects ink onto the print medium to form dots on the print medium, and an opposing member which is capable of facing a printing surface of the print medium upstream of the plurality of nozzles of the print head in the transport direction, the control device comprising: a partial printing in which the dots are formed by the print head; and conveying the print medium, alternately performed a plurality of times to cause the print execution unit to print a print image, and the control unit, when causing the print execution unit to print the print image, causes the print execution unit to execute first partial printing, which is the partial printing performed in a state where the print medium faces the opposing member, N times (N is an integer of 2 or more), conveys the print medium a first conveying amount after executing the first partial printing N times, and conveys the print medium a first conveying amount after conveying the first conveying amount, executes second partial printing, which is the partial printing performed in a state where the print medium faces the opposing member, N times, and conveys the second partial printing N times. and after performing the third partial printing N times, the printing medium is transported a second transport amount smaller than the first transport amount, and after transporting the second transport amount, a third partial printing is performed N times, which is the partial printing performed in a state where the printing medium is located at a specific position in the transport direction where a predetermined position of an end of the printing medium on the upstream side in the transport direction faces the opposing member, and after performing the third partial printing N times, the printing medium is transported, and then a fourth partial printing is performed N times, which is the partial printing performed in a state where the printing medium is not facing the opposing member, and the Nth partial printing is printed by the first partial printing. the first region to be printed by N times of the second partial printing includes a first normal region printed only by the first partial printing, and a first end region located upstream of the first normal region in the transport direction and printed by both the first partial printing and the second partial printing; the second region to be printed by N times of the second partial printing includes the first end region, a second normal region located upstream of the first end region in the transport direction and printed by only the second partial printing, and a second end region located upstream of the second normal region in the transport direction and printed by both the second partial printing and the third partial printing;The third area printed by N times of the third partial printing includes at least the second end area and a third end area located upstream of the second end area in the transport direction and printed by both the third partial printing and the fourth partial printing, and may include a third normal area printed only by the third partial printing between the second end area and the third end area, and the fourth area printed by N times of the fourth partial printing includes the third end area and a fourth normal area located upstream of the third end area in the transport direction and printed only by the fourth partial printing, and among the multiple first raster lines in the first normal area and aligned in the transport direction, N adjacent first raster lines are each printed by different first partial printings, and among the multiple second raster lines in the first normal area and aligned in the transport direction, N adjacent second raster lines are each printed by different second partial printings. a plurality of third raster lines in the third normal area that are aligned in the transport direction, N adjacent third raster lines are printed with the third partial printing that are different from each other, and a plurality of fourth raster lines in the fourth normal area that are aligned in the transport direction, N adjacent fourth raster lines are printed with the fourth partial printing that are different from each other, and the control device carries out (N-1) transport of the printing medium between N of the first partial printings, between N of the second partial printings, between N of the third partial printings, and between N of the fourth partial printings, respectively, and a transport amount of the (N-1) transport of the printing medium is determined by the number of upstream raster lines that are located upstream in the transport direction of the plurality of raster lines that can be printed in N of the third partial printings when the second transport amount is set to a minimum value, 3 The printing device, wherein the number of raster lines printed in the edge region is determined to be equal to or greater than the number of raster lines printed in the edge region.

[0007] According to the above configuration, the N third partial printings are performed in a state where the printing medium is located at a specific position, that is, in a state where a predetermined position of the end portion on the upstream side in the transport direction of the printing medium faces the opposing member. This allows the third partial printing to be performed in a stable state of the printing medium, thereby improving the print quality. Here, the second carry amount may be small because the N third partial printings are performed in a state where the printing medium is located at a specific position. Furthermore, according to the above configuration, when the second carry amount is set to a minimum value, among the multiple raster lines that can be printed in the N third partial printings, the number of raster lines located upstream in the transport direction from the multiple raster lines that can be printed in the N second partial printings is determined to be equal to or greater than the number of raster lines printed in the first end area. As a result, it is possible to print raster lines that are equal to or greater than the number of raster lines printed in the first end area in the N third partial printings upstream in the transport direction from the multiple raster lines that can be printed in the N second partial printings. As a result, the number of raster lines in the third end region printed in both the N third partial printings and the N fourth partial printings can be made equal to or greater than the number of raster lines in the first end region. Therefore, it is possible to prevent banding from becoming noticeable due to an inability to ensure the number of raster lines in the third end region. As described above, with the above configuration, it is possible to improve the image quality of the image printed by the print execution unit.

[0008] The technology disclosed in this specification can be realized in various forms, such as a printing device, a control method for a print execution unit, a printing method, a computer program for realizing the functions of these devices and methods, a recording medium on which the computer program is recorded, etc. [Brief description of the drawings]

[0009] [Figure 1] FIG. 2 is a block diagram showing the configuration of a printer 200 according to the embodiment. [Diagram 2] FIG. 2 is a diagram showing a schematic configuration of a printing mechanism 100. [Diagram 3] FIG. 1 is a perspective view of a paper tray 145 and a plurality of pressing members 146. [Figure 4]4 is a flowchart of a printing process. [Diagram 5] FIG. 11 is a first explanatory diagram of printing in the normal printing mode. [Figure 6] 11 is a flowchart of a print data output process for a normal print mode. [Figure 7] FIG. 13 is a diagram showing divided pattern data PD and the recording rate of partial printing executed at head positions P0 to P2. [Figure 8] FIG. 11 is an explanatory diagram of printing in a barcode print mode. [Figure 9] FIG. 13 is a second explanatory diagram of printing in the normal printing mode. [Figure 10] FIG. 13 is a second explanatory diagram of printing in the normal printing mode. [Figure 11] FIG. [Figure 12] FIG. 11 is an explanatory diagram of a partial print set according to a comparative example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] A. First Example: A-1: Configuration of Printer 200 Next, the embodiment will be described based on an example embodiment. Fig. 1 is a block diagram showing the configuration of a printer 200 according to the example embodiment.

[0011] The printer 200 includes, for example, a print mechanism 100 as a print execution unit, a CPU 210 as a control device, a non-volatile storage device 220 such as a hard disk drive, a volatile storage device 230 such as a RAM, an operation unit 260 such as buttons or a touch panel for acquiring operations by a user, a display unit 270 such as a liquid crystal display, and a communication unit 280. The communication unit 280 includes a wired or wireless interface for connecting to a network NW. The printer 200 is connected to an external device, for example, a user's terminal device 300, via the communication unit 280 so as to be able to communicate with the external device.

[0012] The volatile storage device 230 provides a buffer area 231 for temporarily storing various intermediate data generated when the CPU 210 performs processing. The non-volatile storage device 220 stores a computer program PG. In this embodiment, the computer program PG is a control program for controlling the printer 200. The computer program PG may be provided by being stored in the non-volatile storage device 220 at the time of shipment of the printer 200. Alternatively, the computer program PG may be provided in a form downloaded from a server, or in a form stored on a DVD-ROM or the like. The CPU 210 executes the computer program PG to perform, for example, a printing process described below. As a result, the CPU 210 controls the printing mechanism 100 to print an image on a printing medium (for example, paper).

[0013] The printing mechanism 100 can form dots on paper M using ink (droplets) of each of cyan (C), magenta (M), yellow (Y), and black (K), thereby performing color printing. The printing mechanism 100 includes a print head 110, a head drive unit 120, a main scanning unit 130, and a transport unit 140.

[0014] FIG. 2 is a diagram showing a schematic configuration of the printing mechanism 100. As shown in FIG. 2, the main scanning unit 130 includes a carriage 133 and a sliding shaft 134. The carriage 133 carries the print head 110. The sliding shaft 134 holds the carriage 133 so that it can move back and forth along the main scanning direction (the X-axis direction in FIG. 2). The main scanning unit 130 uses the power of a main scanning motor (not shown) to move the carriage 133 back and forth (also called scanning) along the sliding shaft 134. This achieves main scanning, which moves the print head 110 back and forth along the main scanning direction relative to the paper M.

[0015] The conveying section 140 holds the paper M and conveys the paper M in a conveying direction AR (+Y direction in FIG. 2) that intersects with the main scanning direction. As shown in FIG. 2A, the conveying section 140 includes an upstream roller pair 142, a downstream roller pair 141, a paper tray 145, and a plurality of pressing members 146. Hereinafter, the upstream side (-Y side) of the conveying direction AR will also be simply referred to as the upstream side, and the downstream side (+Y side) of the conveying direction AR will also be simply referred to as the downstream side.

[0016] The upstream roller pair 142 holds the paper M upstream (-Y side) of the print head 110, and the downstream roller pair 141 holds the paper M downstream (+Y side) of the print head 110. The paper platform 145 is located between the upstream roller pair 142 and the downstream roller pair 141, and is disposed in a position facing the nozzle forming surface 111 of the print head 110. The downstream roller pair 141 and the upstream roller pair 142 are driven by a transport motor (not shown), whereby the paper M is transported in the transport direction AR.

[0017] While the main scanning unit 130 is performing a main scan of the print head 110, the head driving unit 120 (FIG. 1) supplies a driving signal to the print head 110 to drive the print head 110. In accordance with the driving signal, the print head 110 ejects ink onto the paper being transported by the transport unit 140 to form dots.

[0018] FIG. 2B illustrates the configuration of the print head 110 as viewed from the -Z side (the lower side in FIG. 2). As shown in FIG. 2B, a plurality of nozzle rows consisting of a plurality of nozzles, that is, nozzle rows NC, NM, NY, and NK that eject the above-mentioned C, M, Y, and K inks, are formed on the nozzle forming surface 111 of the print head 110. Each nozzle row includes a plurality of nozzles NZ aligned along the transport direction AR. The positions of the plurality of nozzles NZ in the transport direction AR (+Y direction) are different from each other, and aligned along the transport direction AR at a predetermined nozzle interval NT. The nozzle interval NT is the length in the transport direction AR between two nozzles NZ adjacent to each other in the transport direction AR among the plurality of nozzles NZ. Of the nozzles that constitute these nozzle rows, the nozzle NZ located on the most upstream side (-Y side) is also called the most upstream nozzle NZu. Of these nozzles NZ, the nozzle NZ located on the most downstream side (+Y side) is called the most downstream nozzle NZd. The length in the transport direction AR from the most upstream nozzle NZu to the most downstream nozzle NZd plus the nozzle spacing NT is also called the nozzle length D. The nozzle length D is expressed as the number of nozzles included in each nozzle row, with the number of nozzles used as a unit. Note that in an actual product, among the multiple nozzles NZ, the nozzles NZ near both ends in the transport direction AR may not be used for printing, but in this embodiment, an example will be described in which printing is performed using all the nozzles NZ of the nozzle length D. The nozzles NZ used for printing in this embodiment are called usable nozzles.

[0019] The nozzle rows NC, NM, NY, and NK are positioned differently in the main scanning direction (X direction in FIG. 2B), and overlap each other in the transport direction AR (Y direction in FIG. 2B). For example, in the example of FIG. 2B, the nozzle row NM is disposed in the +X direction of the nozzle row NY that ejects Y ink.

[0020] The transport section 140 will be further described with reference to Fig. 3. Fig. 3 is a perspective view of the paper tray 145 and a plurality of pressing members 146. Fig. 3(A) shows a state in which the paper sheet M is not held, and Fig. 3(B) shows a state in which the paper sheet M is held. The paper tray 145 includes a plurality of high support members HP, a plurality of low support members LP, and a flat plate BB.

[0021] The flat plate BB is a plate member that is approximately parallel to the main scanning direction (X direction) and the transport direction (+Y direction). The upstream end (-Y side) of the flat plate BB is located near the upstream roller pair 142. The downstream end (+Y side) of the flat plate BB is located near the downstream roller pair 141.

[0022] As shown in FIG. 3(A), a plurality of high support members HP and a plurality of low support members LP are alternately arranged along the X direction on a flat plate BB. That is, each low support member LP is disposed between two high support members HP adjacent to the low support member. Each support member HP, LP is a rib extending along the Y direction. As shown in FIG. 2(A), the upstream end (-Y side) of each high support member HP is located at the upstream end of the flat plate BB. The downstream end (+Y side) of each high support member HP is located at the center of the flat plate BB in the Y direction. The positions of both ends of each low support member LP in the Y direction are the same as the positions of both ends of the high support member HP in the Y direction.

[0023] The multiple pressing members 146 are disposed at positions on the +Z side of the multiple low support members LP. The positions of the multiple pressing members 146 in the X direction are the same as the positions of the multiple low support members LP in the X direction. That is, the position of each pressing member 146 in the X direction is located between two high support members HP adjacent to that pressing member 146. The multiple pressing members 146 are plate members that are inclined so as to approach the low support members LP in the -Y direction. The positions of the multiple pressing members 146 in the Y direction are upstream of the print head 110 (-Y side) and downstream of the upstream roller pair 142 (+Y side).

[0024] As shown in FIG. 3B, when the paper M is transported, the multiple high support members HP and the multiple low support members LP face the surface Mb side opposite to the printing surface, and support the paper M from the surface Mb side. The multiple pressing members 146 face the printing surface Ma, and press the paper M from the printing surface Ma side. In this way, the multiple high support members HP, the multiple low support members LP, and the multiple pressing members 146 hold the paper M in a state in which it is deformed into a wavy shape along the X direction (FIG. 3B). Then, the paper M is transported in the transport direction (-Y direction) in a state in which it is deformed into a wavy shape at a position facing the nozzle forming surface 111 of the print head 110. By deforming the paper M into a wavy shape, the rigidity of the paper M against deformation along the Y direction can be increased. As a result, the paper M is deformed so as to be warped along the Y direction, and it is possible to prevent the paper M from floating up from the paper base 145 toward the print head 110 side, or the paper M from sagging toward the paper base 145 side. If the paper M floats up or sags, the position at which the dots are formed may shift, causing a deterioration in the quality of the printed image, for example, deterioration in image quality due to banding. Furthermore, if the paper M floats up, the paper may come into contact with the print head 110 and become soiled.

[0025] When the upstream end (-Y end) of the paper M being transported is located upstream (-Y side) of position Ys in FIG. 2A, the paper M is held down by the presser member 146. When the upstream end of the paper M being transported is located downstream (+Y side) of position Ys in FIG. 2A, the paper M is not held down by the presser member 146. When the paper M is held down by the presser member 146, the paper M is held more stably than when the paper M is not held down by the presser member 146, and the distance between the paper M and the nozzle forming surface 111 is also stable. For this reason, in order to stabilize the dot formation positions and stabilize the image quality, it is preferable to perform printing in a state where the paper M is held down by the presser member 146 as much as possible.

[0026] A-2. Printing process The CPU 210 (FIG. 1) of the printer 200 executes a print process based on a print instruction input by a user via the operation unit 260. The print instruction includes a designation of image data indicating an image to be printed. FIG. 4 is a flowchart of the print process. In S110, the CPU 210 acquires the image data designated by the print instruction from the non-volatile storage device 220. Alternatively, the print instruction and the image data may be acquired from the terminal device 300. The acquired image data is image data having various formats, such as JPEG compressed image data and image data described in a page description language.

[0027] In S120, the CPU 210 executes a rasterization process on the acquired image data to generate RGB image data. This results in the acquisition of RGB image data as the target image data of this embodiment. The RGB image data is bitmap data that includes RGB values ​​for each pixel. The RGB values ​​are color values ​​in the RGB color system that include, for example, three component values ​​of red (R), green (G), and blue (B).

[0028] In S130, the CPU 210 converts the RGB image data into print data. Specifically, the CPU 210 executes color conversion processing and halftone processing on the RGB image data. The color conversion processing is processing for converting the RGB values ​​of a plurality of pixels included in the RGB image data into CMYK values. The CMYK values ​​are color values ​​of the CMYK color system including component values ​​(in this embodiment, component values ​​of C, M, Y, and K) corresponding to the inks used in printing. The color conversion processing is executed, for example, by referring to a known lookup table that specifies the correspondence between RGB values ​​and CMYK values. The halftone processing is processing for converting the color-converted image data into print data (also called dot data). The print data is data that represents the dot formation state for each pixel for each color component of CMYK. The value of each pixel of the dot data indicates the dot formation state in two gradations, for example, "no dot" and "dot", or in four gradations, "no dot", "small", "medium", and "large". The halftone processing is executed using a known method such as a dither method or an error diffusion method.

[0029] In S140, the CPU 210 judges whether the print mode of the printing to be performed is the barcode print mode. In this embodiment, printing can be performed in two print modes: the barcode print mode and the normal print mode. The barcode print mode is a print mode suitable for printing images including one-dimensional codes such as barcodes and two-dimensional codes such as QR codes (registered trademark). The normal print mode is a print mode suitable for printing general images, such as characters, photographs, and drawings (graphics). For example, an instruction to specify the print mode is input by the user together with a print instruction, and the CPU 210 judges whether the print mode is the barcode print mode based on the instruction.

[0030] Alternatively, CPU 210 may determine whether or not the image to be printed contains a one-dimensional code or a two-dimensional code by analyzing the image data acquired in S110 and the print data acquired in S130. In this case, if the analysis result shows that the image to be printed contains a one-dimensional code or a two-dimensional code, the print mode to be executed is determined to be the barcode print mode, and if the image to be printed does not contain a one-dimensional code or a two-dimensional code, the print mode to be executed is determined to be the normal print mode. do.

[0031] If the print mode to be executed is the normal print mode (S140: NO), the CPU 210 executes print data output processing for the normal print mode in S150. If the print mode to be executed is the barcode print mode (S140: YES), the CPU 210 executes print data output processing for the barcode print mode in S160. The print data output processing is a process of generating partial print data for each partial print, which will be described later, adding various control data to the partial print data, and outputting the data to the print mechanism 100. The control data includes data that specifies the conveyance amount of the sheet conveyance to be executed before the partial print. In the print data output processing, the partial print data is output the same number of partial prints to be executed. Details of the print data output processing will be described later, but in the print data output processing for the normal print mode, an end area, which will be described later, is provided in the image to be printed, and in the print data output processing for the barcode print mode, an end area is not provided in the image to be printed.

[0032] By executing the print process, the CPU 210 can cause the print mechanism 100 to print the print image PI. Specifically, the CPU 210 controls the head drive unit 120, the main scanning unit 130, and the transport unit 140 to alternately perform partial printing and sheet transport multiple times, thereby performing printing. In one partial printing, with the paper M stopped on the paper tray 145, one main scan is performed while ejecting ink from the nozzles NZ of the print head 110 onto the paper M, thereby printing a portion of the print image on the paper M. In one sheet transport, the paper M is transported in the transport direction AR by a transport amount determined in the print data output process.

[0033] Fig. 5 is a first explanatory diagram of printing in the normal printing mode of the first embodiment. Fig. 5 shows an example of a print image PI printed on paper M. The print image PI includes multiple raster lines (for example, RL1 in Fig. 5) that each extend in the X direction (main scanning direction during printing) in Fig. 5 and differ from one another in position in the Y direction (transport direction AR during printing). Each raster line is a line on which multiple dots can be formed.

[0034] 5 further illustrates the head position, i.e., the relative position of the print head 110 in the transport direction with respect to the paper M. Head positions P0a, P0b, P1a, P1b, P2a, P2b, P3a, P3b, P4a, and P4b are the head positions for the final 10 partial prints out of the multiple partial prints.

[0035] The hatched area of ​​the head position is the area where the nozzles NZ (also called the used nozzles) used for printing in the partial printing performed at that head position are located. The used nozzles are all or a part of the usable nozzles.

[0036] In Figure 5, the print image PI formed on the paper M includes a plurality of normal areas (e.g., non-hatched areas NA0 to NA4 in Figure 5) and a plurality of end areas (e.g., hatched areas SA0 to SA3 in Figure 5).

[0037] Each normal area is printed by two partial printings (so-called multi-pass printing). Two partial printings for printing one normal area are also called a partial printing set. For example, the normal area NA0 in FIG. 5 is printed by a partial printing set performed at head positions P0a and P0b. Similarly, the normal areas NA1, NA2, NA3, and NA4 are printed by a partial printing set performed at head positions P1a and P1b, a partial printing set performed at head positions P2a and P2b, a partial printing set performed at head positions P3a and P3b, and a partial printing set performed at head positions P4a and P4b, respectively.

[0038] Of the multiple raster lines aligned in the transport direction AR within the normal area, two adjacent raster lines (two raster lines that are continuous in the transport direction AR) are printed by different partial printing. For example, of the multiple raster lines aligned in the transport direction AR within the normal area, the odd-numbered raster lines are printed by an earlier partial printing that constitutes a partial printing set that prints the normal area, and the even-numbered raster lines are printed by a later partial printing that constitutes the partial printing set. This doubles the printing resolution of the print image PI in the transport direction AR compared to when the normal area is printed by only one partial printing.

[0039] The area RA0 printed by the partial printing set executed at head positions P0a and P0b includes the normal area NA0 and an end area SA0 upstream (-Y side) of the normal area NA0. The area RA1 printed by the partial printing set executed at head positions P1a and P1b includes the normal area NA1, an end area SA0 downstream (+Y side) of the normal area NA1, and an end area SA1 upstream (-Y side) of the normal area NA1. The area RA2 printed by the partial printing set executed at head positions P2a and P2b includes the normal area NA2, an end area SA1 downstream (+Y side) of the normal area NA2, and an end area SA2 upstream (-Y side) of the normal area NA2. The area RA3 printed by the partial printing set executed at head positions P3a and P3b includes the normal area NA3, an end area SA2 downstream (+Y side) of the normal area NA3, and an end area SA3 upstream (-Y side) of the normal area NA3. The area RA4 printed by the partial printing set executed at head positions P4a and P4b includes the normal area NA4 and an end area SA3 downstream (+Y side) of the normal area NA4.

[0040] In the normal regions, each raster line in the region is printed by only one partial printing. For example, in each raster line of the normal region NAk (k is an integer from 0 to 4) in FIG. 5, dots are formed by only one partial printing that constitutes a partial printing set performed at head positions Pka and Pkb. Therefore, dots of a specific color in each raster line of the normal region NAk, for example, dots of C, are formed using one nozzle NZ of the nozzle row NC that corresponds to the raster line.

[0041] In the edge region, the raster lines within the region are printed by two partial printings. For example, in each raster line of the edge region SAl (l is an integer from 0 to 3) in Fig. 5, dots are formed by both one partial printing constituting a partial printing set performed at head positions Pla and Plb, and one partial printing constituting a partial printing set performed at head positions P(l+1)a and P(l+1)b. Therefore, dots of a specific color in each raster line of the edge region SAl, for example, dots of C, are formed using two nozzles NZ of the nozzle row NC that correspond to the raster line.

[0042] The length H (FIG. 5) of the end region in the transport direction AR, with the raster line as the unit, is, for example, 3 to several tens of raster lines, and in this embodiment it is 8. In this embodiment, since the nozzles NZ and the raster lines correspond to each other, using the raster line as a unit is equivalent to using the number of nozzles as a unit.

[0043] The reason for providing the edge region will be explained. Suppose that the print image is composed only of the image printed in the normal region without providing the edge region. In this case, a defect called banding may occur in which white or black stripes appear at the boundary between two normal regions adjacent to each other in the transport direction AR due to variations in the transport amount of the paper M. Banding reduces the image quality of the print image PI. By providing an edge region between the two normal regions and printing an image in the region, the defect called banding described above can be suppressed. This is because in the edge region, dots on one raster line are formed by two partial printings, and it is possible to suppress all dots on one raster line from being shifted in the same way with respect to all dots on other raster lines.

[0044] In this embodiment, among the multiple partial print sets, the partial print sets except the last partial print set are performed in a state where the paper M is pressed by the pressing member 146, that is, in a state where the printing surface of the paper M faces the pressing member 146. The last partial print set is performed in a state where the paper M is not pressed by the pressing member 146. Here, in this embodiment, in order to perform printing in a state where the paper M is pressed by the pressing member 146 as much as possible, the partial print set before the last is performed in a state where the specific position SP near the upstream end of the paper M is pressed by the pressing member 146. As shown in FIG. 5, the partial print set before the last is a partial print set executed at the head positions P3a and P3b. In FIG. 5, the pressing member 146 shown on the upstream side of the head position P3b is illustrated at a position in the transport direction AR where the specific position SP is pressed. This makes it possible to reduce the size of the image printed in the last partial print set, that is, the partial print set executed at the head positions P4a and P4b in FIG. 5. Therefore, the last partial print set can be executed using only a downstream portion of the multiple nozzles NZ. As a result, the last partial print set is executed in a state where the paper M is held only by the downstream roller pair 141, but the length from the downstream roller pair 141 to the upstream end of the paper M can be shortened during the last partial printing. This makes it possible to prevent the upstream end of the paper M from touching the nozzle forming surface 111 of the print head 110, and to stabilize the dot formation position. Hereinafter, the head positions P3a and P3b where the pressing member 146 presses the specific position SP of the paper M are also referred to as end pressing head positions.

[0045] In FIG. 5, the sheet transports T0b, T1a, T1b, T2a, T2b, T3a, T3b, and T4a are further illustrated by arrows. The sheet transports T1a, T2a, T3a, and T4a are sheet transports (also called intra-set transports) that are performed between two partial prints that constitute a partial print set. The transport amounts of the sheet transports T1a, T2a, T3a, and T4a are also called intra-set transport amounts ΔTL. The usable nozzles of the first partial print that constitutes the partial print set are the nozzles NZ of the multiple nozzles NZ of the nozzle length D, excluding several nozzles NZ on the downstream side (+Y side) according to the intra-set transport amount ΔTL. The usable nozzles of the subsequent partial print that constitutes the partial print set are the nozzles NZ of the multiple nozzles NZ of the nozzle length D, excluding several nozzles NZ on the upstream side (-Y side) according to the intra-set transport amount ΔTL. The maximum length NL in the transport direction AR that can be printed with one partial print set (that is, the length of the range in the transport direction AR in which the usable nozzles are located; FIG. 5) is (2D-ΔTL) in units of raster lines.

[0046] Sheet transport T0b is a sheet transport performed immediately before the partial print set performed at head positions P1a and P1b. Sheet transports T1b, T2b, and T3b are sheet transports performed immediately before the partial print set performed at head positions P2a and P2b, immediately before the partial print set performed at head positions P3a and P3b, and immediately before the partial print set performed at head positions P4a and P4b, respectively. The transport amounts of sheet transports T0b, T1b, T2b, and T3b are also called pre-set transport amounts TL.

[0047] As will be described later when describing the print data output process (FIG. 6), the pre-set carry amount TL varies depending on the nozzle shift amount NS (described later), and the minimum value TLmin of the pre-set carry amount TL is expressed in units of raster lines and is 1 in this embodiment. The minimum value TLmin may be a value greater than 1 (for example, 2, 3, 5). In this embodiment, the intra-set carry amount ΔTL is the value obtained by subtracting the minimum value TLmin of the pre-set carry amount TL from the width H of the end areas SA0 to SA3 in the carry direction AR (ΔTL=(H-TLmin)). The intra-set carry amount ΔTL is a fixed value expressed in units of raster lines and is set to an odd number. As described above, in this embodiment, the width H of the end areas SA0 to SA3 in the carry direction AR is 8, and the minimum value TLmin is 1, so the intra-set carry amount ΔTL is 7.

[0048] A-3. Print data output process for normal print mode Next, the print data output process for the normal printing mode in S150 of Fig. 3 will be described. As described above, the print data output process is a process in which partial print data is generated for each partial print SP using the print data generated in S130, various control data is added to the partial print data, and the partial print data is output to the printing mechanism 100. Fig. 6 is a flowchart of the print data output process for the normal printing mode.

[0049] The print data generated in S130 of Fig. 4 represents a print image PI (Fig. 5) to be printed. Therefore, the print data includes a plurality of raster data corresponding to a plurality of raster lines included in the print image PI.

[0050] In S200, the CPU 210 acquires raster data corresponding to one raster line of interest (hereinafter also referred to as "target raster data") from among the multiple raster data. The target raster line is selected one by one from the multiple raster lines included in the print image PI and aligned in the transport direction AR, in sequence from the downstream side of the transport direction AR during printing (the +Y side in FIG. 5).

[0051] Here, the partial print set that prints the target raster line is also called the target partial print set. However, when the target raster line is printed in two partial print sets, that is, when the target raster line is located in the end area, the partial print set that is performed first among the two partial print sets is the target partial print set. For example, when the raster lines RL1 and RL2 in FIG. 5 are the target raster line, the target partial print set is the partial print set performed at the head positions P0a and P0b (FIG. 5). The nozzle NZ used to form dots on the target raster line in the target partial print set is also called the target nozzle. For example, when the raster line to be processed first, that is, the raster line located at the most downstream of the print image PI, is the target raster line, the target nozzle is the nozzle NZ located at the most downstream of the usable nozzles in the target partial print set.

[0052] In S205, the CPU 210 judges whether the target raster data is to be divided. If the target raster line is located within the edge region, in other words, if the target nozzle is one of a predetermined number (eight in this embodiment) of nozzles NZ located at the upstream end of the usable nozzles of the target portion print set, the target raster data is judged to be a target for division. If the target raster line is located within the normal region, the target raster data is judged not to be a target for division.

[0053] If the target raster data is not to be divided (S205: NO), that is, if the target raster line is located within the normal region, in S210, the CPU 210 assigns the target raster data to the target nozzle. The target nozzle at the start of the print data output process is the nozzle NZ at the downstream end of the usable nozzles in the target portion print set.

[0054] If the target raster data is to be split (S205: YES), i.e., if the target raster line is located within the edge region, in S215, CPU 210 splits the target raster data into data for the target partial printing set and data for the next partial printing set.

[0055] Specifically, the CPU 210 acquires the divided pattern data PD corresponding to the target raster line. FIG. 7 is a diagram showing the divided pattern data PD and the recording rates of partial printing executed at head positions P0 to P2. As shown in FIG. 7(A), the divided pattern data PD is binary data having values ​​corresponding to each pixel of the target raster line. A value of "0" in the divided pattern data PD indicates that a dot corresponding to that pixel should be formed in the target partial print set. A value of "1" in the divided pattern data PD indicates that a dot corresponding to that pixel should be formed in the partial print set next to the target partial print set.

[0056] Here, the recording rate R0 in FIG. 7B is the recording rate in the partial print set performed at head positions P0a and P0b. The recording rate R1 is the recording rate in the partial print set performed at head positions P1a and P1b. The recording rate R2 is the recording rate in the partial print set performed at head positions P2a and P2b. FIG. 7B shows the recording rates R0, R1, and R2 relative to the position in the transport direction AR. In the range of the transport direction AR corresponding to the normal area NA0, the recording rate R0 is 100%. Similarly, in the range of the transport direction AR corresponding to the normal areas NA1 and NA2, the recording rates R1 and R2 are 100%.

[0057] In the range of the transport direction AR corresponding to the edge region SA0, the recording rate R0 decreases linearly toward the upstream side in the transport direction AR (the lower side in FIG. 7B). In the range of the transport direction AR corresponding to the edge region SA0, the recording rate R1 decreases linearly toward the downstream side in the transport direction AR (the upper side in FIG. 7B). In the range of the transport direction AR corresponding to the edge region SA0 (FIG. 5), the sum of the recording rates R0 and R1 is 100%. The same is true for the recording rates R1 and R2 in the range of the transport direction AR corresponding to the edge region SA1.

[0058] The division pattern data PD is generated so as to realize the above-mentioned recording rate according to the position of the target raster line in the edge region in the transport direction AR. CPU 210 divides the target raster data into data for the target partial print set and data for the next partial print set according to the division pattern data PD.

[0059] In S220, the CPU 210 assigns data for the target partial print set to the target nozzle. In S225, the CPU 210 assigns data for the next partial print set to the corresponding nozzle for the next partial print set. Here, the corresponding nozzle is the nozzle NZ used to form dots on the target raster line in the next partial print set. The corresponding nozzle at the start of the print data output process is the nozzle NZ at the downstream end of the usable nozzles of the next partial print set. For example, if the raster line RL2 in FIG. 5 is the target raster line, the corresponding nozzle is the nozzle NZ located at the end on the downstream side (the +Y side in FIG. 5) of the usable nozzles at head positions P1a and P1b.

[0060] In S230, the CPU 210 updates the number indicating the corresponding nozzle of the next partial print set. That is, the CPU 210 changes the number indicating the corresponding nozzle to the number of the nozzle NZ that is one nozzle upstream from the current corresponding nozzle.

[0061] In S235, the CPU 210 updates the number indicating the nozzle of interest. That is, the CPU 210 changes the number indicating the nozzle of interest to the number of the nozzle NZ that is one nozzle upstream from the current nozzle of interest.

[0062] In S240, CPU 210 determines whether raster data has been assigned to all active nozzles in the target partial print set (all active nozzles for two partial prints). Specifically, if the updated number indicating the target nozzle exceeds the number of the most upstream nozzle among the active nozzles, it is determined that raster data has been assigned to all active nozzles. If there is an active nozzle to which raster data has not been assigned (S240: NO), the process returns to S200.

[0063] If raster data has been assigned to all of the operating nozzles (S240: YES), then in S245 the CPU 210 outputs to the printing mechanism 100 partial print data for the two partial prints that make up the target portion printing set, and two transport amount data. The partial print data is a group of raster data assigned to the operating nozzles. The transport amount data is control data that indicates the transport amount. The two transport amount data include a pre-set transport amount TL of the sheet transport that should be executed immediately before the target portion printing set, and an in-set transport amount ΔTL. As described above, the in-set transport amount ΔTL is a fixed value (7 in this embodiment).

[0064] When the target portion print set is the first partial print set, the pre-set carry amount TL is determined so that the position on the paper M where the downstream end of the print image PI should be printed coincides with the position of the downstream end nozzle NZ among the available nozzles in the target portion print set. When the target portion print set is the second partial print set, the pre-set carry amount TL is a value obtained by subtracting the number of raster lines in the end area and the carry amount ΔTL from the maximum length NL in the carry direction AR that can be printed in one partial print set. In this embodiment, as described above, the maximum length NL is (2D-ΔTL), and the number of raster lines in the end area is the length H in the carry direction AR of the end area, so the pre-set carry amount TL determined when the target portion print is the second partial print is (2D-H-2ΔTL). This carry amount is determined in advance on the premise that the head position of the second partial print set will not become the end pressing head position. When the target portion print set is the third or subsequent partial print set, the pre-set carry amount TL is determined in S280, which will be described later. When the printing mechanism 100 receives the partial print data for two times and the transport amount data for two times, it performs sheet transport by the pre-set transport amount TL indicated by the transport amount data, and then performs the first partial printing using the partial print data. Furthermore, the printing mechanism 100 performs sheet transport by the in-set transport amount ΔTL indicated by the transport amount data, and then performs the second partial printing. In this way, two partial printings that constitute the target partial printing set are performed.

[0065] In S250, the CPU 210 judges whether all partial printing sets have been processed. If all partial printing sets have been processed (S250: YES), the CPU 210 ends the print data output process. If all partial printing sets have not been processed (S250: NO), the CPU 210 updates the target portion printing set in S251. That is, the target portion printing set is set to the target portion printing set next to the current target portion printing set. Specifically, the corresponding nozzle number of the next target portion printing set at the current time is set to the new target nozzle number. The corresponding nozzle number of the next target portion printing set at the current time is the number of the nozzle at the downstream end of the normal area. For this reason, the new target nozzle number is set to the number of the nozzle at the downstream end of the normal area.

[0066] In S252, the CPU 210 determines whether the target portion print set is a partial print set executed at the end holding head position. In the example of Fig. 5, if the target portion print set is a partial print set executed at head positions P3a and P3b, the target portion print set is determined to be a partial print set executed at the end holding head position. If the target portion print set is not a partial print set executed at the end holding head position (S252: NO), the process proceeds to S255.

[0067] In S255, the CPU 210 calculates the excess amount VO of the pressing reference position in the target portion print set. The excess amount VO indicates the length from the pressing reference position RL to the most upstream nozzle NZ among the usable nozzles in the head position in the target portion print set when the most upstream nozzle NZ is located upstream of the pressing reference position RL. The pressing reference position RL (FIG. 5) is a position in the transport direction AR determined on the paper M. When the most upstream nozzle NZ in the target portion print set is located upstream of the pressing reference position RL, the next partial print set of the target portion print set is executed at the end pressing head position (head positions P3a, P3b in FIG. 5). In the example of FIG. 5, when the partial print set executed at the head positions P2a, P2b is the target portion print set, the most upstream nozzle NZ at the head positions P2a, P2b is located upstream of the pressing reference position RL, so the excess amount VO shown in FIG. 5 is calculated. The unit of the excess amount VO is indicated, for example, by the number of raster lines.

[0068] When the most upstream nozzle is located at the same position as the holding reference position RL or downstream of the holding reference position RL, the excess amount VO is 0. In the example of Fig. 5, when the partial print set executed at head positions P0a, P0b, or the partial print set executed at head positions P1a, P1b is the target partial print set, the most upstream nozzle at these head positions is located downstream of the holding reference position RL, so the excess amount VO is 0.

[0069] In S265, the CPU 210 sets the nozzle shift amount NS of the partial printing set next to the target partial printing set based on the excess amount VO. The nozzle shift amount NS indicates the number of nozzles NZ (also called downstream unused nozzles) that are not used on the downstream side among the available nozzles in the partial printing set next to the target partial printing set. When the nozzle shift amount NS is 0, no downstream unused nozzles are provided. When the nozzle shift amount NS is 1 or more, the nozzles NZ of the available nozzles on the downstream side (the +Y side in FIG. 5) corresponding to the nozzle shift amount NS are downstream unused nozzles. Therefore, in this case, the available nozzles excluding the downstream unused nozzles are the used nozzles of the partial printing set next to the target partial printing set. Specifically, in S265, the CPU 210 sets the nozzle shift amount NS to the excess amount VO.

[0070] If the target partial printing set is a partial printing set executed at the end holding head position (S252: YES), then in S272, the CPU 210 sets the nozzle shift amount NS to 0. If the target partial printing set is at the end holding head position, the next partial printing set will be the last partial printing set, because in the last partial printing set, no unused nozzles are set at the downstream end of the usable nozzles.

[0071] In S280, the CPU 210 determines the transport amount of the sheet transport performed after the target portion print set, in other words, the pre-set transport amount TL of the sheet transport performed immediately before the next partial print set of the target portion print set, based on the nozzle shift amount NS. The pre-set transport amount TL is calculated in units of raster lines. The pre-set transport amount TL is determined to be a value obtained by subtracting the number of raster lines in the end area, the transport amount ΔTL, and the nozzle shift amount NS from the maximum length NL in the transport direction AR that can be printed in one partial print set. In this embodiment, the maximum length NL is (2D-ΔTL), and the number of raster lines in the end area is the length H of the end area in the transport direction AR, so the pre-set transport amount TL is (2D-H-2ΔTL-NS).

[0072] In S285, the CPU 210 sets the number of the corresponding nozzle of the partial printing set next to the target partial printing set to an initial value. The initial value is the number of the nozzle located upstream from the downstream end by the nozzle shift amount NS among the usable nozzles of the partial printing set. After S285, the CPU 210 returns the process to S200.

[0073] The printing of this embodiment described above will be further described with reference to FIG. 5. In the partial printing set prior to the partial printing set executed at the head positions P3a and P3b, which are the end pressing head positions, it is preferable to perform printing using all available nozzles in order to achieve high-speed printing. For this reason, the nozzle shift amount NS of the partial printing set executed at the head positions P1a and P1b and the partial printing set executed at the head positions P2a and P2b is set to 0 (S265 in FIG. 6), and the pre-set conveyance amount TL of the sheet conveyances T0b and T1b immediately before these partial printing sets is set to (2D-H-2ΔTL) (S280 in FIG. 6). In addition, since it is preferable that the last partial printing set executed at the head positions P4a and P4b is executed in a state in which the length from the downstream roller pair 141 to the upstream end of the paper M is as short as possible, it is preferable to execute it using the nozzles downstream of the head positions P4a and P4b. For this reason, the nozzle shift amount NS of the last partial print set is set to 0 (S272 in FIG. 6), and the transport amount TL of the sheet transport T3b immediately before the last partial print set is set to (2D-H-2ΔTL) (S280 in FIG. 6).

[0074] Head positions P3a and P3b, which are edge holding head positions, are positions in the transport direction AR that are fixed with respect to the paper M. For this reason, the nozzle shift amount NS of the partial print set executed at head positions P3a and P3b is set according to the position of head position P2b in the transport direction AR (S255, S260 in FIG. 6), and the transport amount TL of the sheet transport T2b immediately before the partial print set executed at head positions P3a and P3b is determined (S280 in FIG. 6). Therefore, except for the case where head position P2b with respect to the paper M happens to be downstream by (2D-H-2ΔTL) from the edge holding head position, the nozzle shift amount NS of the partial print set at head positions P3a and P3b is set to a value greater than 0, and the transport amount TL of the sheet transport T2b is determined to a value smaller than (2D-H-2ΔTL).

[0075] A-4. Print data output process for barcode printing mode Next, the print data output process for the barcode printing mode in S160 in Fig. 3 will be described. Fig. 8 is an explanatory diagram of printing in the barcode printing mode. In Fig. 8, an explanatory diagram similar to Fig. 5 is shown for printing in the barcode printing mode. The barcode printing mode differs from the normal printing mode in Fig. 5 in that no end area is provided in the print image PIb. For this reason, in Fig. 8, the print image PIb formed on the paper M includes multiple normal areas (for example, areas NA0 to NA4 in Fig. 8) and does not include end areas.

[0076] Therefore, in the barcode printing mode, the area RA0 printed by the partial print set executed at the head positions P0a and P0b is printed only by the partial print set executed at the head positions P0a and P0b, and is not printed by the other partial print sets. Similarly, the area RA1 is printed only by the partial print set executed at the head positions P1a and P1b, and the area RA2 is printed only by the partial print set executed at the head positions P2a and P2b. The area RA3 is printed only by the partial print set executed at the head positions P3a and P3b, and the area RA4 is printed only by the partial print set executed at the head positions P4a and P4b.

[0077] The reason why the end area is not provided in the barcode printing mode will be explained. In one-dimensional codes such as barcodes and two-dimensional codes such as QR Code (registered trademark), the contents of information indicated by these codes differ depending on the thickness and interval of the lines and blocks that constitute these codes. For this reason, it is important that the thickness and interval of the lines and blocks that constitute the codes in the printed image are printed with high precision. In the end area, since dots on one raster line are formed by multiple partial printings, dots formed by one partial printing and dots formed by other partial printings on one raster line may be misaligned in the transport direction AR. In this case, the thickness of the lines expressed by one raster line may vary, which may cause the thickness and interval of the lines and blocks of the printed code to vary. For this reason, the end area is not provided in the barcode printing mode of this embodiment.

[0078] In the barcode printing mode, as in the normal printing mode, among the multiple raster lines aligned in the transport direction AR in the normal area, two adjacent raster lines (two raster lines consecutive in the transport direction AR) are printed by different partial printing. For example, among the multiple raster lines aligned in the transport direction AR in the normal area, the odd-numbered raster lines are printed by the first partial printing that constitutes the partial printing set that prints the normal area, and the even-numbered raster lines are printed by the second partial printing that constitutes the partial printing set. For this reason, the print resolution in the transport direction AR of the print image PIb in the barcode printing mode is the same as the print resolution in the transport direction AR of the print image PI in the normal printing mode.

[0079] Furthermore, the in-set transport amount ΔTLx in the barcode printing mode (for example, the transport amounts of sheet transports T1a, T2a, T3a, and T4a in FIG. 8) is smaller than the in-set transport amount ΔTL in the normal printing mode (7 in this embodiment) (ΔTL>ΔTLx). In this embodiment, the in-set transport amount ΔTLx in the barcode printing mode is 3 in units of raster lines.

[0080] Because the intra-set transport amount ΔTLx in the barcode printing mode is smaller than in the normal printing mode, the number of usable nozzles in the barcode printing mode is greater than in the normal printing mode. For this reason, the length NLx (FIG. 8) of the transport direction AR that can be printed with one partial print set in the barcode printing mode is (2D-ΔTLx), which is longer than the length NL (FIG. 5, 2D-ΔTL) of the transport direction AR that can be printed with one partial print set in the normal printing mode (NLx>NL).

[0081] In this way, in the barcode printing mode, the length NLx in the transport direction AR that can be printed with one partial print set is long, and by not providing an end area, the number of partial prints required to print the print image can be reduced compared to the normal printing mode. Therefore, in the barcode printing mode, the printing time can be shorter than the printing speed in the normal printing mode.

[0082] The print data output process for the barcode printing mode is executed in the same manner as the print data output process for the normal printing mode in FIG. 6. However, in the barcode printing mode, since no end area is provided as described above, in S205 in FIG. 6, the target raster data is not determined to be a division target. Therefore, in the barcode printing mode, the process always proceeds to S210 in FIG. 6 after S205 in FIG. 6, and S215 to S230 in FIG. 6 are not executed. Also, in the normal printing mode, in S280 in FIG. 6, the pre-set carry amount TL is determined by the formula (2D-H-2ΔTL-NS). In the barcode printing mode, since no end area is provided, H=0, and the intra-set carry amount is ΔTLx, in S280 in FIG. 6, the pre-set carry amount TL is determined by the formula (2D-2ΔTLx-NS).

[0083] In the present embodiment described above, the reason why the in-set transport amount ΔTL in the normal printing mode is set to a value larger than the in-set transport amount ΔTLx in the barcode printing mode will be described. In the example of FIG. 5, the positions of the head positions P2a and P2b in the transport direction AR and the positions of the head positions P3a and P3b, which are the end pressing head positions, are relatively far apart. Here, the positions of the head positions P2a and P2b in the transport direction AR vary due to the margin on the downstream side (the +Y side in FIG. 5) of the printed image PI and the length of the paper M in the transport direction AR. Also, when there is a blank portion in the middle of the printed image PI in the transport direction AR, if printing is performed by skipping the blank portion, the positions of the head positions P2a and P2b in the transport direction AR vary according to the blank portion included in the printed image PI. For this reason, the positions of the head positions P2a and P2b in the transport direction AR and the positions of the head positions P3a and P3b in the transport direction AR, which are the end pressing head positions, may be close to each other. Printing in such a case will be described while comparing this embodiment with a comparative example.

[0084] FIG. 9 is a second explanatory diagram of printing in the normal printing mode of the first embodiment. FIG. 10 is an explanatory diagram of printing in the normal printing mode of the comparative example. FIG. 9(A) shows an explanatory diagram of this embodiment similar to FIG. 5, in which the positions of head positions P2a and P2b in the transport direction AR and the positions of head positions P3a and P3b, which are end pressing head positions, in the transport direction AR are close to each other. FIG. 10(A) shows an explanatory diagram of the comparative example, in which the positions of head positions P2a and P2b in the transport direction AR and the positions of head positions P3a and P3b, which are end pressing head positions, in the transport direction AR are close to each other. In the comparative example, unlike this embodiment, the intra-set transport amount is set to the intra-set transport amount ΔTLx of the barcode printing mode.

[0085] In the example of Fig. 9 and Fig. 10, the position of head positions P2a, P2b in the transport direction AR and the position of head positions P3a, P3b, which are the end pressing head positions, are close to each other, so the sheet transport T2b is set to 3 (three raster lines) (S280 in Fig. 6). In such a case, in this embodiment (Fig. 9), the length of the transport direction AR of the end area SA2 and the length of the transport direction AR of the end area SA3 can both be secured by the length H (H raster lines) that should be secured as the length of the end area. In the comparative example (Fig. 10), the length of the transport direction AR of the end area SA2 can be secured by the length H that should be secured, but the length of the transport direction AR of the end area SA3 is shorter than the length H that should be secured.

[0086] Fig. 9(B) shows an enlarged view of the area AA surrounded by a dashed line in Fig. 9(A). Fig. 10(B) shows an enlarged view of the area AAx surrounded by a dashed line in Fig. 10(A). In Fig. 9(B) and Fig. 10(B), the circles and squares shown inside the head positions P2a, P2b, P3a, P3b, P4a, and P4b indicate nozzles NZ. Black circles indicate nozzles NZ that print the end region. Squares indicate nozzles NZ that print the normal region. White circles indicate nozzles NZ that are not used.

[0087] In this embodiment of FIG. 9B, the nozzle group NG2 at the head positions P2a, P2b, P3a, and P3b is a nozzle group that prints the end area SA2. The nozzle group NG3 at the head positions P3a, P3b, P4a, and P4b is a nozzle group that prints the end area SA3. The nozzle group NGn at the head positions P3a and P3b is a nozzle group that prints the normal area NA3. Each of the nozzle groups NG2 and NG3 includes nozzles NZ for a length H (eight raster lines in this embodiment) that should be secured in the transport direction AR. That is, in this embodiment of FIG. 9B, the length of the end area SA2 and the end area SA3 in the transport direction AR is secured by the length H that should be secured.

[0088] This is because the intra-set transport amount ΔTL is set to a value obtained by subtracting the minimum value TLmin of the pre-set transport amount TL from the width H of the end areas SA0 to SA3 in the transport direction AR (ΔTL=(H-TLmin), 7 in this embodiment). That is, in this embodiment, since the intra-set transport amount ΔTL is set to 7, regardless of the transport amount of the sheet transport T2b, eight or more nozzles (nozzle group NGd in FIG. 9(B)) used for printing at the head positions P3a and P3b can be secured upstream (lower side in FIG. 9(B)) of the nozzle NZend at the upstream end (lower end in FIG. 9(B)) used for printing at the head positions P2a and P2b. In the example of FIG. 9(B), the transport amount of the sheet transport T2b is 3, so the nozzle group NGd (FIG. 9(B)) includes 10 nozzles. It can be seen from FIG. 9(B) that even if the transport amount of the sheet transport T2b is 1, at least eight nozzles are secured. If eight nozzles are secured, it is possible to print the edge area SA3 including eight raster lines.

[0089] In other words, in this embodiment, even when the transport amount of sheet transport T2b is set to the minimum value (1 in this embodiment), the intra-set transport amount ΔTL is determined so that, among the multiple raster lines printable in the partial printing set at head positions P3a, P3b, the number of upstream raster lines located upstream of the multiple raster lines printable at head positions P2a, P2b is equal to or greater than the number H of raster lines printed in the edge region SA3. As a result, a sufficient length in the transport direction AR of the edge region SA3 can be ensured, so that appropriate printing of the edge region SA3 as described in FIG. 7 can be performed and noticeable banding in the printed image PI can be suppressed.

[0090] In the example of FIG. 9B, the nozzle group NGd (FIG. 9B) includes 10 nozzles, so the end area SA3 is printed using 8 upstream nozzles (nozzles belonging to the nozzle group NG3 in FIG. 9B) among the 10 nozzles. Then, the normal area NA3 is printed using the remaining 2 nozzles (nozzles belonging to the nozzle group NGn in FIG. 9B). When the conveyance amount of the sheet conveyance T2b is 1, 8 nozzles are secured, so the end area SA3 is printed using these 8 nozzles, and the normal area NA3 is not printed. That is, in this case, the end area SA2 and the end area SA3 are directly adjacent to each other, and there is no normal area between the end area SA2 and the end area SA3. In this way, the area RA3 printed in the partial printing performed at the head positions P3a and P3b includes at least the end area SA2 and the end area SA3, but there may be a case where a normal area is included (FIG. 9) or not included (not shown) between the end area SA2 and the end area SA2.

[0091] In the comparative example of FIG. 10B, the intra-set transport amount ΔTLx is smaller than the intra-set transport amount ΔTL in this embodiment. For this reason, in FIG. 10B, only six nozzles (nozzle group NGdx in FIG. 10B) can be secured as nozzles used for printing at head positions P3a and P3b upstream of the upstream end nozzle NZend used for printing at head positions P2a and P2b. When the transport amount of sheet transport T2b is the minimum value (1 in this embodiment), the number of nozzles that can be secured is further reduced to only four. For this reason, in the comparative example of FIG. 10B, when the transport amount of sheet transport T2b is small, the length of the transport direction AR of the end area SA3 becomes Hx, which is smaller than the length H that should be secured. Therefore, in the comparative example, for example, since the appropriate printing of the end area SA3 described in FIG. 7 cannot be executed, banding may be noticeable in the end area SA3.

[0092] Furthermore, according to this embodiment, the intra-set transport amount ΔTLx in the barcode printing mode is smaller than the intra-set transport amount ΔTL in the normal printing mode. As a result, an appropriate intra-set transport amount can be set according to the printing mode. For example, this allows the number of nozzles used in the partial printing set executed at head positions P1a and P1b in the barcode printing mode to be greater than the number of nozzles used in the partial printing set in the normal printing mode (NLx>NL). Therefore, the printing time in the barcode printing mode can be shorter than the printing time in the normal printing mode.

[0093] As can be seen from the above description, the two partial printings performed at head positions P1a and P2a in the normal printing mode of this embodiment are examples of the first partial printing, and the two partial printings performed at head positions P2a and P2b in the normal printing mode are examples of the second partial printing. The two partial printings performed at head positions P3a and P3b in the normal printing mode are examples of the third partial printing, and the two partial printings performed at head positions P4a and P4b in the normal printing mode are examples of the fourth partial printing. In addition, the end areas SA1, SA2, SA3, and SA4 in the normal printing mode are examples of the first end area, second end area, third end area, and fourth end area, respectively. The normal areas NA1, NA2, NA3, and NA4 in the normal printing mode are examples of the first normal area, second normal area, third normal area, and fourth normal area, respectively. Furthermore, the transport amount of sheet transport T1b in the normal printing mode is an example of a first transport amount, and the transport amount of sheet transport T2b is an example of a second transport amount. The end holding head position is an example of a specific position. The two partial printings performed at head positions P1a and P2a in the barcode printing mode are each an example of a fifth partial printing, and the two partial printings performed at head positions P2a and P2b in the normal printing mode are each an example of a sixth partial printing. The two partial printings performed at head positions P3a and P3b in the normal printing mode are each an example of a seventh partial printing, and the two partial printings performed at head positions P4a and P4b in the normal printing mode are each an example of an eighth partial printing.

[0094] B. Second Example In the first embodiment described above, one partial print set includes two partial prints. In the second embodiment, one partial print set includes three partial prints. FIG. 11 is an explanatory diagram of the partial print sets in the second embodiment. FIGS. 11(A) to (C) each show the head positions of two partial print sets. The partial print set consisting of three partial prints performed at head positions P2a, P2b, and P2c is the partial print set that prints the area RA2 in FIG. 5. The partial print set consisting of three partial prints performed at head positions P3a, P3b, and P3c is the partial print set that prints the area RA3 in FIG. 5.

[0095] In the second embodiment, one partial print set includes three partial prints, so two intra-set transports are performed while one partial print set is executed. In Fig. 11 (A) to (C), sheet transports T2a and T2b performed after head positions P2a and P2b are intra-set transports of the partial print set executed at head positions P2a, P2b, and P2c. Sheet transports T3a and T3b performed after head positions P3a and P3b are intra-set transports of the partial print set executed at head positions P3a, P3b, and P3c. Sheet transport T2c is a sheet transport performed between the partial print set executed at head positions P2a, P2b, and P2c and the partial print set executed at head positions P3a, P3b, and P3c.

[0096] The transport amount of the intra-set transport of one partial printing set is set to be the same as the transport amount of the corresponding intra-set transport of another partial printing set. For example, the transport amount of sheet transport T2a is the same as the transport amount of sheet transport T3a, and the transport amount of sheet transport T2b is the same as the transport amount of sheet transport T3b. Even if the transport amounts of the two intra-set transports in one partial printing set are different, it is sufficient as long as they follow the following rules (1) and (2). By setting in this way, it is possible to perform appropriate printing so that the raster lines are lined up at intervals that are one-third the nozzle interval NT (FIG. 2(B)) of the print head 110. (1) The remainder when the first sheet transport of the two intra-set transports (for example, T2a) is divided by the number of partial prints (three) included in one partial print set is either 1 or 2. (2) The remainder when the sum of the first and second sheet transports of two intra-set transports (for example, T2a and T2b) is divided by the number of partial prints (3) contained in one partial print set is the other of 1 and 2.

[0097] Furthermore, in the second embodiment, the transport amount of the two intra-set transports is determined so that the sum of the total transport amount of the two intra-set transports and the minimum value of the sheet transport T2c performed between two partial printing sets (1 in this embodiment) is greater than or equal to the length H (6 in this embodiment) of the transport direction AR of the end area SA3 to be secured.

[0098] In the second embodiment, one of the transport amounts for the intra-set transport shown in Figures 11A to 11C is adopted. In Figure 11A, the transport amounts of sheet transports T2a and T3a are each 2, and the transport amounts of sheet transports T2b and T3b are each 5, for each raster line. The sum of the transport amounts of sheet transports T2a and T2b, and the sum of the transport amounts of sheet transports T3a and T3b are each 7.

[0099] 11B, in units of raster lines, the transport amounts of sheet transports T2a and T3a are each 5, and the transport amounts of sheet transports T2b and T3b are each 2. The sum of the transport amounts of sheet transports T2a and T2b and the sum of the transport amounts of sheet transports T3a and T3b are each 7.

[0100] 11C, in units of raster lines, the transport amounts of sheet transports T2a and T3a are each 4, and the transport amounts of sheet transports T2b and T3b are each 4. The sum of the transport amounts of sheet transports T2a and T2b and the sum of the transport amounts of sheet transports T3a and T3b are each 8.

[0101] According to the second embodiment, the transport amount of the two intra-set transports is determined so that the sum of the transport amount of the two intra-set transports and the minimum value (1 in this embodiment) of the sheet transport T2c performed between two partial print sets is equal to or greater than the length H (6 in this embodiment) of the transport direction AR of the end area SA3 to be secured, so that the length of the transport direction AR of the end area SA3 can be secured by the length H of the transport direction AR to be secured. As a result, as in the first embodiment, appropriate printing of the end area SA3 can be performed, and noticeable banding in the printed image can be suppressed.

[0102] In each of FIGS. 11A to 11C, nozzle group NG1 is a nozzle group that prints end area SA1 (FIG. 5). Nozzle group NG2 is a nozzle group that prints end area SA2 (FIG. 5). Nozzle group NG3 is a nozzle group that prints end area SA3 (FIG. 5). Even if sheet transport T2c is at its minimum value (1 in this embodiment), nozzle groups NG1, NG2, and NG3 each include six nozzles that are positioned differently in the transport direction AR. In this way, it can be seen that the length H of end areas SA1 to SA3 in the transport direction AR is ensured even if sheet transport T2c is at its minimum value (1 in this embodiment).

[0103] Fig. 12 is an explanatory diagram of a partial print set of a comparative example. In the comparative example of Fig. 12, the conveyance amount of the sheet conveyances T2a and T3a is 2, and the conveyance amount of the sheet conveyances T2b and T3b is 2, each in units of a raster line. The sum of the conveyance amounts of the sheet conveyances T2a and T2b and the sum of the conveyance amounts of the sheet conveyances T3a and T3b are 4, respectively. That is, in the comparative example of Fig. 12, unlike the second embodiment of Fig. 11, the sum (4 in this embodiment) of the sum of the conveyance amount of the two intra-set conveyances and the minimum value (1 in this embodiment) of the sheet conveyance T2c performed between the two partial print sets is less than the length H (6 in this embodiment) of the conveyance direction AR of the end area SA3 to be secured.

[0104] For this reason, in the comparative example, when the sheet transport T2c is at its minimum value (1 in this embodiment), the nozzle group NG3 includes only five nozzles whose positions in the transport direction AR are different from each other. That is, in the comparative example, when the sheet transport T2c is at its minimum value (1 in this embodiment), it is understood that the length H of the end area SA3 in the transport direction AR cannot be secured.

[0105] C. Modifications (1) In the first embodiment, one partial print set includes two partial prints, and in the second embodiment, one partial print set includes three partial prints. Alternatively, one partial print set may be configured by four or more partial prints, for example, four or five partial prints. In general, one partial print set may be configured by N partial prints (N is an integer of 2 or more). In this case, among the multiple raster lines aligned in the transport direction in each normal area, adjacent N raster lines are printed by different partial prints included in one partial print set. Then, while one partial print set is executed, (N-1) intra-set transports are executed. The transport amount of the (N-1) intra-set transports is determined so that the sum of the total transport amount of the (N-1) intra-set transports and the minimum transport amount of the sheet transport between one partial print set and the next partial print set is equal to or greater than the length H in the transport direction of the number of raster lines printed in the end area. According to this configuration, the length of the end region in the transport direction is ensured, and banding in the printed image can be prevented from becoming noticeable.

[0106] (2) In the first embodiment, the printing modes include a normal printing mode and a barcode printing mode. Alternatively, the printing modes may include a normal printing mode and a high-speed printing mode. Then, printing in the barcode printing mode of the first embodiment may be executed in the high-speed printing mode. Also, the printing modes do not have to include the barcode printing mode or the high-speed printing mode.

[0107] Furthermore, although the within-set carry amount ΔTLx in the barcode printing mode in the first embodiment is smaller than the within-set carry amount ΔTL in the normal printing mode, the within-set carry amount ΔTLx in the barcode printing mode may be equal to the within-set carry amount ΔTL in the normal printing mode.

[0108] (3) The printing process in FIG. 4 and the print data output process in FIG. 6 are examples, and are not limited thereto. For example, in the processes in FIG. 4 and FIG. 6, the entire image data is converted into print data (S130 in FIG. 4), and then the print data output process in FIG. 6 is executed. Instead of this, for example, the conversion of the print data may be executed for each raster data acquired in S200 in FIG. 6. Also, in the print data output process, the raster data is sequentially assigned to the nozzles to be used, and each time the assignment of one partial print is completed, the assigned raster data group is output as partial print data for one partial print. Instead of this, the print data may be divided to generate all partial print data, and after the conveyance amount of all the sheet conveyances is determined, the partial print data and the conveyance amount data may be output.

[0109] (4) As the print medium, instead of paper M, other media, such as OHP film, CD-ROM, or DVD-ROM, may be used.

[0110] (5) In each of the above embodiments, the control device that executes the printing process in Fig. 4 is the CPU 210. Alternatively, the control device may be another type of device, for example, a user's terminal device 300. In this case, for example, the terminal device 300 operates as a printer driver by executing a driver program, and executes the printing process in Fig. 4 as part of its function as the printer driver. In this case, the terminal device supplies the partial print data and carry amount data to the printer 200 as a print execution unit, thereby causing the printer 200 to execute printing.

[0111] (6) The control device that executes the printing process in Fig. 4 may be, for example, a server that acquires image data from printer 200 or terminal device 300, generates the partial print data and transport amount data described above using the image data, and transmits these data to printer 200. Such a server may be multiple computers that are capable of communicating with each other via a network.

[0112] (7) In each of the above embodiments, a part of the configuration realized by hardware may be replaced by software, and conversely, a part or all of the configuration realized by software may be replaced by hardware. For example, a part of the printing process in FIG. 4 may be realized by a dedicated hardware circuit (e.g., ASIC) that operates according to instructions from CPU 210.

[0113] The present invention has been described above based on examples and modifications, but the above-described embodiments of the invention are intended to facilitate understanding of the present invention and are not intended to limit the present invention. The present invention may be modified or improved without departing from the spirit and scope of the claims, and equivalents thereof are included in the present invention. [Explanation of symbols]

[0114] 100...printing mechanism, 110...print head, 111...nozzle forming surface, 120...head driving section, 130...main scanning section, 133...carriage, 134...sliding shaft, 140...conveying section, 141...downstream roller pair, 142...upstream roller pair, 145...paper stand, 146...member, 200...printer, 210...CPU, 220...non-volatile storage device, 230...volatile storage device, 231...buffer area, 260...operation section, 270...display section, 280...communication section, 300...terminal device, BB...flat plate, D...nozzle length, HP...high support member, HP...high support member, LP...low support member, M...paper, PG...computer program, PI, PIb...printed image

Claims

1. A printing device including a print execution unit and a control device, The print execution unit is a transport unit that transports the print medium in a transport direction; a print head having a plurality of nozzles that eject ink of a specific color, the plurality of nozzles being positioned at different positions in the transport direction, and ejecting ink onto the printing medium to form dots on the printing medium; an opposing member that is capable of opposing a printing surface of the printing medium on an upstream side of the plurality of nozzles of the print head in the transport direction; Equipped with the control device causes the print execution unit to print a print image by alternately executing partial printing, in which the print head forms the dots, and conveying the print medium by the conveying unit, multiple times; When causing the print execution unit to print the print image, the control device A first partial printing, which is the partial printing performed in a state in which the print medium faces the facing member, is performed N times (N is an integer equal to or greater than 2); After the first partial printing is performed N times, the print medium is conveyed a first conveyance amount; After the first transport amount is transported, second partial printing is performed N times, the second partial printing being performed in a state where the print medium faces the opposing member; After the second portion printing is executed N times, the print medium is transported by a second transport amount smaller than the first transport amount; after conveying the second conveyance amount, a third partial printing is executed N times, the third partial printing being executed in a state in which the print medium is positioned at a specific position in the conveyance direction where a predetermined position of an end portion of the print medium on an upstream side in the conveyance direction faces the opposing member; After the third portion printing is performed N times, the print medium is transported. Thereafter, a fourth partial printing, which is the partial printing performed in a state where the print medium is not opposed to the opposing member, is performed N times; a first region printed by the N number of first partial printings includes a first normal region printed only by the first partial printing, and a first end region located upstream of the first normal region in the transport direction and printed by both the first partial printing and the second partial printing, a second region printed by the Nth second partial printing includes the first end region, a second normal region located upstream of the first end region in the transport direction and printed only by the second partial printing, and a second end region located upstream of the second normal region in the transport direction and printed by both the second partial printing and the third partial printing, the third region printed by the Nth third partial printing includes at least the second end region and a third end region located upstream of the second end region in the transport direction and printed by both the third partial printing and the fourth partial printing, and may include a third normal region between the second end region and the third end region that is printed only by the third partial printing; a fourth region printed by the Nth fourth partial printing includes the third end region and a fourth normal region located upstream of the third end region in the transport direction and printed only by the fourth partial printing, Among the plurality of first raster lines in the first normal region that are aligned in the transport direction, N first raster lines that are adjacent to each other are printed in the first partial printing that are different from each other, Among the plurality of second raster lines within the first normal region that are aligned in the transport direction, N adjacent second raster lines are printed in the second partial printing that are different from each other, Among the third raster lines in the third normal area that are aligned in the transport direction, N third raster lines adjacent to each other are printed in the third partial printing that are different from each other, Among the plurality of fourth raster lines in the fourth normal area that are aligned in the transport direction, N adjacent fourth raster lines are printed in the fourth partial printing that are different from each other, the control device executes (N-1) transports of the print medium between N times of the first partial printing, between N times of the second partial printing, between N times of the third partial printing, and between N times of the fourth partial printing, a transport amount for the (N-1) transports of the printing medium is determined so that, when the second transport amount is set to a minimum value, the number of upstream raster lines located upstream in the transport direction of the multiple raster lines that can be printed in N times of the third partial printing is greater than or equal to the number of raster lines printed in the third end region.

2. 2. The printing device according to claim 1, a transport amount for the (N-1)th transport of the printing medium is determined so that the sum of the total transport amount for the (N-1)th transport of the printing medium and the minimum value of the second transport amount is greater than or equal to the length in the transport direction of the number of raster lines printed in the third end area.

3. 3. The printing device according to claim 1, the control device is capable of executing printing in a first print mode and printing in a second print mode; the print image is a first print image printed in the first print mode, When the control device causes the print execution unit to print a second print image to be printed in the second print mode, A fifth partial printing, which is the partial printing performed in a state where the print medium faces the facing member, is performed N times; After the fifth portion printing is executed N times, the print medium is conveyed a fifth conveyance amount; After the fifth conveyance distance, a sixth partial printing is performed N times, the sixth partial printing being performed in a state where the print medium faces the opposing member; After the sixth portion printing is executed N times, the print medium is transported a sixth transport amount that is smaller than the fifth transport amount; After the sixth transport distance, a seventh partial printing is performed N times, the partial printing being performed in a state in which the print medium is positioned at a specific position in the transport direction where a predetermined position of an end portion of the print medium on an upstream side in the transport direction faces the opposing member; After the seventh portion printing is performed N times, the print medium is transported; Thereafter, an eighth partial printing, which is the partial printing performed in a state where the print medium is not opposed to the opposing member, is performed N times; A fifth region that is printed in the Nth fifth partial printing is printed only in the fifth partial printing, A sixth region printed in the sixth partial printing N times is printed only in the sixth partial printing, The seventh region printed in the Nth seventh partial printing is printed only in the seventh partial printing, The eighth region printed in the Nth eighth partial printing is printed only in the eighth partial printing, Among the plurality of fifth raster lines in the fifth region that are aligned in the transport direction, N adjacent fifth raster lines are printed in the fifth partial printing that are different from each other, Among the plurality of sixth raster lines in the sixth region that are aligned in the transport direction, N sixth raster lines adjacent to each other are printed by the sixth partial printing that is different from each other, Among the multiple seventh raster lines in the seventh region that are aligned in the transport direction, N adjacent seventh raster lines are printed in the seventh partial printing that are different from each other, Among the multiple eighth raster lines in the eighth region that are aligned in the transport direction, N adjacent eighth raster lines are printed by the eighth partial printing that is different from each other, the control device executes (N-1) transports of the print medium between N prints of the fifth portion, between N prints of the sixth portion, between N prints of the seventh portion, and between N prints of the eighth portion, respectively; A printing device, wherein a transport amount of the (N-1)th transport of the printing medium in the second printing mode is smaller than a transport amount of the (N-1)th transport of the printing medium in the first printing mode.

4. 4. The printing device according to claim 3, A printing device, wherein the number of nozzles used in the fifth partial printing and the sixth partial printing in the second printing mode is greater than the number of nozzles used in the first partial printing and the second partial printing in the first printing mode.

5. 5. The printing device according to claim 3, A printing device, wherein the second print image printed in the second print mode includes a code image showing at least one of a one-dimensional code and a two-dimensional code.

6. The printing device according to any one of claims 1 to 5, further comprising: a carriage that carries the print head and scans the print medium in a scanning direction perpendicular to the transport direction; The control device executes the partial printing by causing the print head to eject ink onto the print medium while scanning the carriage in the scanning direction.

7. The printing device according to any one of claims 1 to 6, The region in which the upstream raster line is located among the multiple raster lines that can be printed in the N third partial printings is at least the third end region including the same number of the upstream raster lines as the raster lines printed in the first end region, a third normal region when the number of the upstream raster lines is greater than the number of raster lines printed in the first end region.

8. A computer program for a control device that controls a print execution unit, The print execution unit is a transport unit that transports the print medium in a transport direction; a print head having a plurality of nozzles that eject ink of a specific color, the plurality of nozzles being positioned at different positions in the transport direction, and ejecting ink onto the printing medium to form dots on the printing medium; an opposing member that is capable of opposing a printing surface of the printing medium on an upstream side of the plurality of nozzles of the print head in the transport direction; Equipped with the computer program causes a computer of the control device to cause the print execution unit to print a print image by alternately executing partial printing, in which the print head forms the dots, and conveying the print medium by the conveying unit, multiple times; The computer program, when causing the print execution unit to print the print image, A first partial printing, which is the partial printing performed in a state in which the print medium faces the facing member, is performed N times (N is an integer equal to or greater than 2); After the first partial printing is performed N times, the print medium is conveyed a first conveyance amount; After the first transport amount is transported, second partial printing is performed N times, the second partial printing being performed in a state where the print medium faces the opposing member; After the second portion printing is executed N times, the print medium is transported by a second transport amount smaller than the first transport amount; after conveying the second conveyance amount, a third partial printing is executed N times, the third partial printing being executed in a state in which the print medium is positioned at a specific position in the conveyance direction where a predetermined position of an end portion of the print medium on an upstream side in the conveyance direction faces the opposing member; After the third portion printing is performed N times, the print medium is transported. Thereafter, a fourth partial printing, which is the partial printing performed in a state where the print medium is not opposed to the opposing member, is performed N times; a first region printed by the N number of first partial printings includes a first normal region printed only by the first partial printing, and a first end region located upstream of the first normal region in the transport direction and printed by both the first partial printing and the second partial printing, a second region printed by the Nth second partial printing includes the first end region, a second normal region located upstream of the first end region in the transport direction and printed only by the second partial printing, and a second end region located upstream of the second normal region in the transport direction and printed by both the second partial printing and the third partial printing, the third region printed by the Nth third partial printing includes at least the second end region and a third end region located upstream of the second end region in the transport direction and printed by both the third partial printing and the fourth partial printing, and may include a third normal region between the second end region and the third end region that is printed only by the third partial printing; a fourth region printed by the Nth fourth partial printing includes the third end region and a fourth normal region located upstream of the third end region in the transport direction and printed only by the fourth partial printing, Among the plurality of first raster lines in the first normal region that are aligned in the transport direction, N first raster lines that are adjacent to each other are printed in the first partial printing that are different from each other, Among the plurality of second raster lines within the first normal region that are aligned in the transport direction, N adjacent second raster lines are printed in the second partial printing that are different from each other, Among the third raster lines in the third normal area that are aligned in the transport direction, N third raster lines adjacent to each other are printed in the third partial printing that are different from each other, Among the plurality of fourth raster lines in the fourth normal area that are aligned in the transport direction, N adjacent fourth raster lines are printed in the fourth partial printing that are different from each other, the computer program causes the computer to execute (N-1) transports of the print medium between N times of the first partial printing, between N times of the second partial printing, between N times of the third partial printing, and between N times of the fourth partial printing; a computer program, the transport amount of the (N-1) transports of the printing medium being determined so that, when the second transport amount is set to a minimum value, the number of upstream raster lines located upstream in the transport direction of the multiple raster lines that can be printed in the N number of the second partial printings is greater than or equal to the number of raster lines printed in the third end region.

Images