Printing device and computer program

Abstract

To improve an image quality of a printed image.SOLUTION: A printing execution part comprises an opposing member that can oppose to a printing surface of a printing medium at a position closer to an upstream in a conveying direction than a plurality of nozzles of a printing head. A control device makes the printing execution part execute second partial printing one or more times and then convey the printing medium by a second conveyance amount smaller than a first conveyance amount, and thereafter makes the printing execution part execute third partial printing that is executed with the printing medium positioned at a specific position at which a predetermined position of an end part at the upstream side in the conveying direction of the printing medium opposes to the opposing member one or more times, and then convey the printing medium, thereafter makes the printing execution part execute fourth partial printing that is executed with the printing medium not opposing to the opposing member one or more times. The control device, when the second conveyance amount is above a reference, determines a range of nozzles to be used in the second partial printing to a first range, and when the second conveyance amount is smaller than the reference, determines the range of nozzles to be used in the second partial printing to a second range smaller than the first range, where the second range does not include a predetermined range of a portion at an upstream side in the conveyance direction, of the first range.SELECTED DRAWING: Figure 8

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 with multiple pass processes, prints a part of the area near the boundary of the band area printed in each pass process in two pass processes. 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) that faces 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 that transports a 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 print medium to form dots on the print medium, and an opposing member that 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, and the control device controls the print execution unit to perform partial printing by forming the dots using the print head, and conveying the print medium by the conveying unit a plurality of times, thereby printing a print image, and the control device, when causing the print execution unit to print the print image, causes the print execution unit to execute first partial printing one or more times, which is the partial printing that is executed in a state where the print medium faces the opposing member, conveys the print medium a first conveying amount after executing the first partial printing one or more times, and after conveying the first conveying amount, causes the control device to execute second partial printing one or more times, which is the partial printing that is executed in a state where the print medium faces the opposing member, and after the first partial printing, the print medium is transported a second transport amount smaller than the first transport amount, and after the second transport amount, a third partial printing is performed one or more times, which is the partial printing performed in a state where the print medium is located at a specific position in the transport direction where a predetermined position of an end of the print medium on the upstream side in the transport direction faces the opposing member, and after the third partial printing is performed one or more times, the print medium is transported, and then a fourth partial printing is performed one or more times, which is the partial printing performed in a state where the print medium is not facing the opposing member, the first region to be printed 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 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 region printed by the 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 printed only by the third partial printing between the second end region and the third end region, and the fourth region printed by the 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, and when the second transport amount is equal to or greater than a reference value, the control device a printing device which determines an active nozzle range in second partial printing to be a first range which is the same as the active nozzle range in the first partial printing, and if the second carry amount is smaller than the reference, determines the active nozzle range in the second partial printing to be a second range which is smaller than the first range, the active nozzle range is a range in the carry direction which is used in the partial printing among the plurality of nozzles, the second range is a range which does not include a predetermined range which is a part of the first range on the upstream side in the carry direction, and an image within an area which corresponds to the predetermined range in the second partial printing is printed in the third partial printing.

[0007] According to the above configuration, the third partial printing is 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. Therefore, the third partial printing can be performed in a stable state of the printing medium, and the print quality can be improved. Here, if the second transport amount, which is the transport amount of the transport performed after the second partial printing, is excessively small, the length in the transport direction of the third region printed in the third partial printing becomes excessively small. In this case, there is a possibility that the length in the transport direction of the second end region printed in both the second partial printing and the third partial printing and the fourth end region printed in both the third partial printing and the fourth partial printing cannot be secured. According to the above configuration, if the second transport amount is larger than a reference, the nozzle range to be used in the second partial printing is determined to be the first range, and if the second transport amount is equal to or smaller than the reference, the nozzle range to be used in the second partial printing is determined to be the second range smaller than the first range. The second range is a range that does not include a predetermined range that is a part of the first range on the upstream side in the transport direction, and an image within an area that corresponds to the predetermined range in the second partial printing is printed in the third partial printing. As a result, it is possible to prevent the length of the third area printed in the transport direction from being excessively small. Therefore, it is possible to prevent the inconvenience of not being able to secure the length of the second end area and the third end area in the transport direction, and therefore to prevent banding from becoming noticeable. 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. 1 is a first explanatory diagram of printing in an embodiment. [Figure 6] 13 is a flowchart of a print data output process. [Figure 7] 6A and 6B are diagrams showing divided pattern data and recording rates of partial printing. [Figure 8] FIG. 2 is a second explanatory diagram of printing in the embodiment. [Figure 9] FIG. [Figure 10] FIG. 1 is a first explanatory diagram of multi-pass printing. [Figure 11] FIG. 2 is a second explanatory diagram of multi-pass printing. [Figure 12] FIG. 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 executes a print data output process. The print data output process is a process in which partial print data is generated for each partial print, which will be described later, and various control data is added to the partial print data and output to the print mechanism 100. The control data includes data that specifies the transport amount TL of the sheet transport to be performed before the partial print. In the print data output process, the partial print data is output the same number of times as the partial print to be performed. The print data output process will be described in detail later.

[0030] This allows the CPU 210 to cause the printing mechanism 100 to print the print image PI. Specifically, the CPU 210 controls the head driving 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 TL determined in the print data output process.

[0031] Fig. 5 is a first explanatory diagram of printing in 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.

[0032] 5 further illustrates head positions P0-P4, i.e., the relative position of the print head 110 in the transport direction with respect to the paper M. Head positions P0-P4 are the head positions for the last five partial prints among the multiple partial prints. In FIG. 5, four sheet transports T0-T3 are illustrated with arrows. For example, sheet transport T0 is a sheet transport that is performed after partial printing performed at head position P0. Sheet transports T1, T2, and T3 are sheet transports that are performed after partial printing performed at head positions P1, P2, and P3, respectively.

[0033] Among the head positions P0 to P4, the hatched range is the range in which the nozzles NZ (also called used nozzles) used for printing in partial printing performed at that head position are located. The used nozzles are all or some of the available nozzles (all nozzles for nozzle length D in this embodiment). In the example of FIG. 5, all available nozzles are used in partial printing performed at head positions P0 to P2. In partial printing performed at head position P3, some nozzles NZ on the downstream side are not used. In partial printing performed at head position P4, some nozzles NZ on the upstream side are not used.

[0034] In FIG. 5, the print image PI formed on the paper M includes a plurality of normal regions (for example, non-hatched regions NA0-NA4 in FIG. 5) and a plurality of end regions (for example, hatched regions SA0-SA3 in FIG. 5). For example, the region RA0 printed in partial printing performed at the head position P0 includes the normal region NA0 and an end region SA0 upstream (-Y side) of the normal region NA0. The region RA1 printed in partial printing performed at the head position P1 includes the normal region NA1, an end region SA0 downstream (+Y side) of the normal region NA1, and an end region SA1 upstream (-Y side) of the normal region NA1. The region RA2 printed in partial printing performed at the head position P2 includes the normal region NA2, an end region SA1 downstream (+Y side) of the normal region NA2, and an end region SA2 upstream (-Y side) of the normal region NA2. The area RA3 printed in partial printing performed at head position P3 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 in partial printing performed at head position P4 includes the normal area NA4 and an end area SA3 downstream (+Y side) of the normal area NA4.

[0035] Each normal area is an area in which each raster line within the area is printed by only one partial printing. For example, in each raster line of the normal area NAk (k is an integer from 0 to 4) in FIG. 5, dots are formed by only partial printing performed at the head position Pk. Therefore, dots of a specific color in each raster line of the normal area NAk, for example, dots of C, are formed using one nozzle NZ of the nozzle row NC that corresponds to the raster line.

[0036] The edge region is a region where the raster lines within the region are printed in 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 in both partial printing performed at head position Pl and partial printing performed at head position P(l+1). 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. For example, the two nozzles NZ that correspond to the raster line of the edge region SAl are the nozzle NZ that corresponds to the raster line in partial printing performed at head position Pl, and the nozzle NZ that corresponds to the raster line in partial printing performed at head position P(l+1).

[0037] The length Ha (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 6. 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.

[0038] 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.

[0039] In this embodiment, among the multiple partial printings, the partial printings except the last partial printing 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 printing 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 printing one before the last is performed in a state where a 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 printing one before the last is a partial printing performed at the head position P3. In FIG. 5, the pressing member 146 shown on the upstream side of the head position P3 is illustrated at a position in the transport direction AR where the specific position SP is pressed. This makes it possible to make the image printed in the last partial printing, that is, the partial printing performed at the head position P4 in FIG. 5, smaller. Therefore, the last partial printing can be performed using only a part of the downstream side of the multiple nozzles NZ. As a result, the final partial printing is performed with the paper M 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 final 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 stabilize the dot formation position. Hereinafter, head position P3 where the pressing member 146 presses the specific position SP of the paper M is also referred to as the end pressing head position.

[0040] A-3. Print data output process Next, the print data output process of S140 in 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.

[0041] 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.

[0042] 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).

[0043] Here, the partial printing of the target raster line is also called the target partial printing. However, when the target raster line is printed in two partial printings, that is, when the target raster line is located in the edge area, the partial printing that is performed first among the two partial printings is the target partial printing. For example, when the raster lines RL1 and RL2 in FIG. 5 are the target raster line, the target partial printing is the partial printing performed at the head position P0 (FIG. 5). The nozzle NZ used to form dots on the target raster line in the target partial printing 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 raster line is the nozzle NZ located at the most downstream of the usable nozzles.

[0044] In S205, the CPU 210 judges whether the raster data of interest is to be divided. If the raster line of interest is located within the edge region, in other words, if the nozzles of interest are a predetermined number (six in this embodiment) of nozzles NZ located at the upstream end of the available nozzles, the raster data of interest is judged to be divided. If the raster line of interest is located within the normal region, the raster data of interest is judged not to be divided.

[0045] If the raster data of interest is not to be divided (S205: NO), that is, if the raster line of interest is located within the normal area, then in S210, CPU 210 assigns the raster data of interest to the nozzle of interest. The nozzle of interest at the start of the print data output process is nozzle NZ at the downstream end of the available nozzles.

[0046] If the target raster data is to be divided (S205: YES), that is, if the target raster line is located within the edge region, in S215, CPU 210 divides the target raster data into data for printing the target portion and data for printing the next portion.

[0047] Specifically, CPU 210 acquires 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 printing. A value of "1" in the divided pattern data PD indicates that a dot corresponding to that pixel should be formed in the partial printing next to the target partial printing.

[0048] Here, the recording rates R0, R1, and R2 in Fig. 7B are the recording rates in partial printing performed at head positions P0, P1, and P2, respectively. Fig. 7B shows the recording rates R0, R1, and R2 relative to positions in the transport direction AR. In the range of the transport direction AR that corresponds to the normal area NA0, the recording rate R0 is 100%. Similarly, in the range of the transport direction AR that corresponds to the normal areas NA1 and NA2, the recording rates R1 and R2 are 100%.

[0049] 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.

[0050] 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 printing the target portion and data for printing the next portion according to the division pattern data PD.

[0051] In S220, the CPU 210 assigns data for printing the target portion to the target nozzle. In S225, the CPU 210 assigns data for printing the next portion to the corresponding nozzle for the next portion. Here, the corresponding nozzle is the nozzle NZ used to form dots on the target raster line in the next portion. The corresponding nozzle at the start of the print data output process is the nozzle NZ at the downstream end of the usable nozzles. 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 position P1.

[0052] In S230, the CPU 210 updates the number indicating the corresponding nozzle for the next partial printing. 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.

[0053] 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.

[0054] In S240, CPU 210 determines whether raster data has been assigned to all active nozzles in printing the target portion. 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.

[0055] When raster data is assigned to all the nozzles in use (S240: YES), in S245, the CPU 210 outputs the partial print data for printing the target portion and the carry amount data to the print mechanism 100. The partial print data is a group of raster data assigned to the nozzles in use. The carry amount data is control data indicating the carry amount TL. When the target portion printing is the first partial printing, the carry amount TL is determined so that the position on the paper M where the downstream end of the print image PI is to be printed coincides with the position of the downstream end nozzle NZ among the nozzles in use. When the target portion printing is the second partial printing, the carry amount TL is a value obtained by subtracting the number of nozzles for the end area from the number of nozzles of the usable nozzles. In this embodiment, the number of nozzles of the usable nozzles is the nozzle length D, and the number of nozzles for the end area is the length Ha of the transport direction AR of the end area, so the carry amount TL determined when the target portion printing is the second partial printing is (D-Ha). This carry amount is determined in advance on the premise that the head position of the second partial printing will not become the end pressing head position. If the target partial printing is the third or subsequent partial printing, the transport amount TL is determined in S280, which will be described later. When the printing mechanism 100 receives the partial print data and the transport amount data, it performs sheet transport by the transport amount TL indicated by the transport amount data, and then performs partial printing using the partial print data.

[0056] In S250, the CPU 210 judges whether all the partial print data has been output. If all the partial print data has been output (S250: YES), the CPU 210 ends the print data output process. If all the partial print data has not been output (S250: NO), the CPU 210 updates the target portion printing in S251. That is, the target portion printing is set to the target portion printing next to the current target portion printing. Specifically, the number of the corresponding nozzle of the next target portion printing at the current time is set to the number of the new target nozzle. The number of the corresponding nozzle of the next target portion printing at the current time is the number of the nozzle at the downstream end of the normal area. For this reason, the number of the new target nozzle is set to the number of the nozzle at the downstream end of the normal area.

[0057] In S252, the CPU 210 determines whether the target portion printing is partial printing performed at the end holding head position. In the example of Fig. 5, if the target portion printing is partial printing performed at head position P3, it is determined that the target portion printing is partial printing performed at the end holding head position. If the target portion printing is not partial printing performed at the end holding head position (S252: NO), the process proceeds to S255.

[0058] In S255, the CPU 210 calculates the excess amount VO of the pressing reference position in the target portion printing. 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 printing 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 printing is located upstream of the pressing reference position RL, the next partial printing of the target portion printing is performed at the end pressing head position (head position P3 in FIG. 5). In the example of FIG. 5, when the partial printing performed at the head position P2 is the target portion printing, the most upstream nozzle NZ at the head position P2 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, for example, the number of nozzles (number of raster lines).

[0059] 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 printing performed at head positions P0 and P1 is the target partial printing, the most upstream nozzle at head positions P0 and P1 is located downstream of the holding reference position RL, so the excess amount VO is 0.

[0060] In S260 to S270, the CPU 210 sets the nozzle shift amount NS for the partial printing next to the printing of the target portion 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 next to the printing of the target portion. 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 on the downstream side (the +Y side in FIG. 5) of the available nozzles that correspond to the nozzle shift amount NS are downstream unused nozzles. Therefore, in this case, the available nozzles excluding the downstream unused nozzles are the nozzles to be used in the partial printing next to the printing of the target portion.

[0061] In S260, the CPU 210 determines whether the excess amount VO is greater than the upper limit NSmax of the nozzle shift amount NS. The upper limit NSmax is a value obtained by subtracting twice the number of nozzles in the end area from the number of usable nozzles. In this embodiment, the number of usable nozzles is the nozzle length D, and the number of nozzles in the end area is Ha, so the upper limit NSmax is (D-2×Ha). In other words, the upper limit NSmax is determined so that the length in the transport direction AR of the area printed in one partial printing (for example, area RA3) is at least twice the length Ha of the transport direction AR of the end area.

[0062] If the nozzle shift amount NS is equal to or less than the upper limit NSmax (S260: NO), the CPU 210 sets the nozzle shift amount NS to the excess amount VO in S265. If the excess amount VO is greater than the upper limit NSmax of the nozzle shift amount NS (S260: YES), the CPU 210 sets the nozzle shift amount NS to the upper limit NSmax in S270.

[0063] If the target portion printing is partial printing performed 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 portion printing is at the end holding head position, the next partial printing will be the last partial printing, because in the last partial printing, no unused nozzles are set at the downstream end of the usable nozzles.

[0064] In S275, CPU 210 calculates the shortening amount VS of the nozzles to be used for printing the portion of interest. The shortening amount VS of the nozzles to be used indicates the number of nozzles NZ (also called upstream unused nozzles) that are not used on the upstream side among the available nozzles in printing the portion of interest. When the shortening amount VS is 0, there are no upstream unused nozzles. When the shortening amount VS is 1 or more, among the available nozzles, the nozzles NZ on the upstream side (the -Y side in FIG. 5) that are shortened by the amount VS are downstream unused nozzles. Therefore, in this case, among the available nozzles, the nozzles excluding the downstream unused nozzles are the nozzles to be used for printing the portion of interest.

[0065] The shortening amount VS is calculated based on the excess amount VO and the nozzle shift amount NS. In this embodiment, the shortening amount VS is a value obtained by subtracting the nozzle shift amount NS from the excess amount VO (VS=VO-NS). Here, if the excess amount VO is equal to or smaller than the upper limit value NSmax, the nozzle shift amount NS is set to the excess amount VO in S265 (NS=VO), and the shortening amount VS is set to 0. If the excess amount VO is greater than the upper limit value NSmax, the nozzle shift amount NS is set to the upper limit value NSmax, which is smaller than the excess amount VO, in S270, and the shortening amount VS is set to a value greater than 0 (VO-NSmax). Note that the shortening amount VS is a value smaller than the number of nozzles Ha for the end region (0≦VS <Ha)。

[0066] In S280, the CPU 210 determines the transport amount TL of the sheet transport performed after printing the target portion based on the nozzle shift amount NS and the shortening amount VS. The transport amount TL is calculated in units of the number of nozzles. The transport amount is a value obtained by subtracting the number of nozzles in the end area, the nozzle shift amount NS, and the shortening amount VS from the number of nozzles in the usable nozzles. In this embodiment, the number of nozzles in the usable nozzles is the nozzle length D, and the number of nozzles in the end area is the length Ha of the end area in the transport direction AR, so the transport amount TL is (D-Ha-NS-VS).

[0067] Here, since the shortening amount VS is (VO-NS), the transport amount TL can also be expressed as (D-Ha-VO). That is, the larger the excess amount VO, the smaller the transport amount TL becomes, and the smaller the excess amount VO, the larger the transport amount TL becomes. Therefore, if the reference value TLth of the transport amount TL is (D-Ha-NSmax), when the excess amount VO is equal to or smaller than the upper limit value NSmax, the shortening amount VS is set to 0, and when the excess amount VO is greater than the upper limit value NSmax, the shortening amount VS is set to a value (VO-NSmax) greater than 0, which can be rephrased as follows. When the transport amount TL is equal to or greater than the reference value TLth, the shortening amount VS is set to 0, and when the transport amount TL is smaller than the reference value TLth, the shortening amount VS is set to a value (VO-NSmax) greater than 0.

[0068] Furthermore, since the transport amount TL decreases as the excess amount VO increases, when the transport amount TL is smaller than the reference value TLth, the smaller the transport amount TL is, the larger the shortening amount VS becomes.

[0069] In S285, the CPU 210 sets the nozzle number of the corresponding nozzle for the partial printing next to the target partial printing to an initial value. The initial value is the nozzle number of the usable nozzle located upstream from the downstream end by the nozzle shift amount NS. After S285, the CPU 210 returns the process to S200.

[0070] The printing of this embodiment described above will be further described with reference to FIG. 5. In partial printing prior to partial printing performed at head position P3, which is the end pressing head position, for example, partial printing performed at head positions P1 and P2, 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 partial printing performed at head positions P1 and P2 is set to 0 (S265 in FIG. 6), and the transport amount TL of sheet transports T0 and T1 immediately before these partial printings is set to (D-Ha) (S280 in FIG. 6). In addition, the last partial printing performed at head position P4 is preferably performed 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, so it is preferable to perform it using nozzles downstream of head position P4. For this reason, the nozzle shift amount NS of the last partial printing is set to 0 (S272 in FIG. 6), and the transport amount TL of sheet transport T3 immediately before the last partial printing is set to (D-Ha) (S280 in FIG. 6).

[0071] Head position P3, which is the edge pressing head position, is a position in the transport direction AR that is fixed with respect to the paper M. For this reason, the nozzle shift amount NS for partial printing performed at head position P3 is set according to the position of head position P2 in the transport direction AR (S260 to S270 in FIG. 6), and the transport amount TL for sheet transport T2 immediately before partial printing performed at head position P3 is determined (S280 in FIG. 6). Therefore, except for the case where head position P2 with respect to the paper M happens to be downstream by (D-Ha) from the edge pressing head position, the nozzle shift amount NS for partial printing at head position P3 is set to a value greater than 0, and the transport amount TL for sheet transport T2 is determined to a value smaller than (D-Ha).

[0072] In the example of Fig. 5, the position of head position P2 in the transport direction AR and the position of head position P3, which is the end pressing head position, are relatively far apart in the transport direction AR. For this reason, the excess amount VO is equal to or less than the upper limit value NSmax. For this reason, in the example of Fig. 5, the nozzle shift amount NS for partial printing at head position P3 is set to the excess amount VO (S260, S265), and the shortening amount VS for partial printing at head position P2 is determined to be 0 (S280).

[0073] Here, the position of head position P2 in the transport direction AR varies due to the margin on the downstream side of the print image PI (the +Y side in FIG. 5) and the length of the transport direction AR of the paper M. Also, if there is a blank portion in the middle of the print image PI in the transport direction AR and printing is performed by skipping the blank portion, the position of head position P2 in the transport direction AR varies depending on the blank portion contained in the print image PI. For this reason, the position of head position P2 in the transport direction AR and the position of head position P3, which is the end pressing head position, may be close to each other in the transport direction AR. Printing in such a case will be explained by comparing this embodiment with a comparative example.

[0074] Fig. 8 is a second explanatory diagram of printing in the first embodiment. Fig. 9 is an explanatory diagram of printing in a comparative example. Fig. 8(A) shows an explanatory diagram of this embodiment similar to Fig. 5, in which the position of head position P2 in the transport direction AR and the position of head position P3, which is the end pressing head position, are close to each other in the transport direction AR. Fig. 9(A) shows an explanatory diagram of a comparative example, in which the position of head position P2 in the transport direction AR and the position of head position P3, which is the end pressing head position, are close to each other in the transport direction AR.

[0075] In this embodiment of FIG. 8A, since the excess amount VO in the partial printing performed at head position P2 is greater than the upper limit value NSmax, the nozzle shift amount NS in the partial printing performed at head position P3 is set to the upper limit value NSmax (S260, S270). Then, corresponding to the nozzle shift amount NS in the partial printing performed at head position P3, the shortening amount VS of the nozzles used in the partial printing performed at head position P2 is determined to be greater than 0 (S275). Therefore, the length in the transport direction AR of the area RA3 printed in the partial printing performed at head position P3 does not become excessively small, and in this embodiment, the length in the transport direction AR of the area RA3 is secured by (2×Ha). As a result, both the length in the transport direction AR of the end area SA2 and the length in the transport direction AR of the end area SA3 can be secured by the number of nozzles Ha that should be secured as the length of the end area.

[0076] FIG. 8(B) shows an enlarged view of the area AA surrounded by a dashed line in FIG. 8(A). In FIG. 8(B), the circles and squares shown inside the head positions P2 to P4 indicate nozzles NZ. The black circles indicate nozzles NZ that print the edge region. The squares indicate nozzles NZ that print the normal region. The white circles indicate nozzles NZ that are not used. The nozzle group NG2 at the head positions P2 and P3 is a nozzle group that prints the edge region SA2. The nozzle group NG3 at the head positions P3 and P4 is a nozzle group that prints the edge region SA3. Each of the nozzle groups NG2 and NG3 includes nozzles NZ equal to the number of nozzles Ha (six in this embodiment) in the transport direction AR.

[0077] The nozzle group NU indicated by a white circle on the upstream side (-Y side) of head position P2 is a nozzle group of unused upstream nozzles. The number of nozzles in the nozzle group NU in the transport direction AR corresponds to the shortening amount VS. The image in the area corresponding to the unused upstream nozzles of head position P2 is printed by partial printing performed at head positions P3 and P4, as shown in FIG. 8(B).

[0078] In the comparative example, the upper limit NSmax and the shortening amount VS of the nozzle shift amount NS are not provided. Therefore, in the comparative example, as shown in FIG. 9A, when the excess amount VO is greater than the upper limit NSmax, the nozzle shift amount NS becomes greater than the upper limit NSmax. Therefore, in FIG. 9A, the length in the transport direction AR of the area RA3 printed in partial printing performed at the head position P3 is smaller than (2×Ha). As a result, the length in the transport direction AR of the end area SA2 is secured by the number of nozzles Ha that should be secured as the length of the end area, but the length in the transport direction AR of the end area SA3 is not secured by the number of nozzles Ha.

[0079] FIG. 9B shows an enlarged view of the area AAx surrounded by a dashed line in FIG. 9. In FIG. 9B, as in FIG. 8B, black circles, squares, and white circles respectively indicate nozzles NZ that print the end area, nozzles NZ that print the normal area, and unused nozzles NZ. The nozzle group NG2x at the head positions P2 and P3 is a nozzle group that prints the end area SA2. The nozzle group NG3x at the head positions P3 and P4 is a nozzle group that prints the end area SA3. The nozzle group NG2x includes nozzles NZ in the transport direction AR for the number of nozzles Ha (six in this embodiment), but the nozzle group NG3x includes only nozzles NZ in the transport direction AR for the number of nozzles Hx (one in FIG. 9B), which is less than the number of nozzles Ha.

[0080] 8 and 9, 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. Thus, the area RA3 printed in partial printing performed at head position P3 includes at least the end area SA2 and the end area SA3, but there may be cases where the normal area is included between the end area SA2 and the end area SA3 (FIG. 5) and cases where the normal area is not included (FIG. 8).

[0081] 8B and 9B, in the embodiment of FIG. 8B, by providing upstream unused nozzles on the upstream side of head position P2, the nozzle group NG2 that prints the end area SA2 is shifted downstream (+Y side) compared to the comparative example. In addition, by setting the nozzle shift amount NS to the upper limit value NSmax, the number of unused nozzles downstream of head position P3 is reduced compared to the comparative example, and the number of used nozzles at head position P3 is increased compared to the comparative example. This allows the length of the transport direction AR of the area RA3 printed by partial printing performed at head position P3 to be secured by (2×Ha). As a result, it can be seen that in the embodiment, both 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 are secured by the number of nozzles Ha that should be secured as the length of the end area.

[0082] In this way, in the comparative example, since the length of the edge region SA3 in the transport direction AR cannot be sufficiently ensured, it is not possible to perform appropriate printing of the edge region SA3 as described in FIG. 7, for example. Therefore, in the comparative example, banding may be noticeable in the edge region SA3 of the printed image PI. In contrast, in this embodiment, since the length of the edge region SA3 in the transport direction AR can be sufficiently ensured, it is possible to perform appropriate printing of the edge region SA3 as described in FIG. 7, and it is possible to prevent banding from being noticeable in the printed image PI.

[0083] As can be seen from the above description, according to this embodiment, when the transport amount TL of the sheet transport T2 is equal to or greater than the reference value TLth, the CPU 210 sets the shortening amount VS to 0 and does not provide upstream unused nozzles (FIG. 5). As a result, the CPU 210 determines the range of the used nozzles in the transport direction AR in the partial printing performed at the head position P2 to be the first range that is the same as the partial printing performed at the head position P1 (FIG. 5). Then, when the transport amount TL of the sheet transport T2 is smaller than the reference value TLth, the CPU 210 sets the shortening amount VS to a value greater than 0 and provides upstream unused nozzles (FIG. 8). As a result, the CPU 210 determines the used nozzles in the partial printing performed at the head position P2 to be the second range in the transport direction AR that is smaller than the partial printing performed at the head position P1 (FIG. 8). The second range is a range that does not include upstream unused nozzles in the first range, that is, a range that does not include a predetermined range that is a part of the upstream side of the transport direction AR. Then, the image within the area corresponding to the upstream unused nozzles at head position P2 is printed in partial printing executed at head position P3 (FIG. 8).

[0084] As a result, as described above, it is possible to prevent the length in the transport direction AR of the area RA3 printed at the head position P3 from becoming excessively short. Therefore, it is possible to prevent the inconvenience of not being able to secure the length in the transport direction AR of the end areas SA2 and SA3, and to prevent banding from becoming noticeable, thereby improving the image quality of the printed image by the printing mechanism 100.

[0085] Furthermore, according to this embodiment, as described above, when the transport amount TL of the sheet transport T2 is smaller than the reference value TLth, the CPU 210 increases the shortening amount VS as the transport amount TL of the sheet transport T2 decreases. That is, the CPU 210 increases the range of the upstream unused nozzles as the transport amount TL decreases. As a result, the range of the used nozzles of the head position P2 can be appropriately determined according to the transport amount TL of the sheet transport T2, so that the length of the end areas SA2 and SA3 in the transport direction can be appropriately secured.

[0086] Furthermore, according to this embodiment, as described above, the upper limit NSmax (D-2×Ha) of the nozzle shift amount NS is set according to the length Ha of the end area in the transport direction AR. As can be seen from the fact that the shortening amount VS is indicated by (VO-NSmax) when it is a value greater than 0, the shortening amount VS is set according to the upper limit NSmax. For this reason, the shortening amount VS is also determined according to the length Ha of the end area in the transport direction AR. That is, the CPU 210 determines the range of the upstream unused nozzles according to the length Ha of the end area in the transport direction AR. Therefore, the length of the end areas SA2 and SA3 in the transport direction can be appropriately secured according to the length Ha of the end area in the transport direction to be secured.

[0087] 8B, in this embodiment, the shortened amount VS of the nozzles in use at head position P2 is determined to be the length Ha of the edge region in the transport direction to be secured minus the transport amount TL of sheet transport T2 (VS=Ha-TL). This allows the length of the edge region SA3 in the transport direction to be secured exactly by Ha. If the shortened amount VS of the nozzles in use at head position P2 is set to be equal to or greater than the length Ha minus the transport amount TL of sheet transport T2, the length of the edge region SA3 in the transport direction can be secured to be equal to or greater than Ha.

[0088] Furthermore, in the print data output process (FIG. 6) of the above embodiment, as described above, the CPU 210 sequentially processes multiple raster lines from the downstream side to the upstream side in the transport direction. Then, when the excess amount VO of the target portion printing is 0, the CPU 210 determines the transport amount of the paper M to be (D-Ha) (S255, S265, S280 in FIG. 6). That is, when the target portion printing is a partial printing that prints multiple raster lines that do not include the raster line on the upstream side of the pressing reference position RL, the transport amount TL of the subsequent sheet transport is determined to be (D-Ha). Then, when the excess amount VO of the target portion printing is greater than 0, the transport amount of the paper M is determined to be (D-Ha-VO), a value smaller than (D-Ha). That is, when the first partial printing that prints multiple raster lines including the raster line on the upstream side of the pressing reference position RL is the target portion printing, the next partial printing should be partial printing performed at the end pressing position. For this reason, the transport amount TL for sheet transport after the first partial printing is determined to be a value (D-Ha-VO) smaller than (D-Ha), and the reduction amount VS for the first partial printing is determined to be a value larger than 0 as necessary (S255 to S280 in FIG. 6). As a result, the transport amount TL and the reduction amount VS can be determined so that partial printing performed at the edge pressing position is appropriately performed using the pressing reference position RL.

[0089] As can be seen from the above description, the partial printing performed at the head position P1 in this embodiment is an example of the first partial printing, the partial printing performed at the head position P2 is an example of the second partial printing, the partial printing performed at the head position P3 is an example of the third partial printing, and the partial printing performed at the head position P4 is an example of the fourth partial printing. Also, the end areas SA1, SA2, SA3, and SA4 are examples of the first end area, the second end area, the third end area, and the fourth end area, respectively. The normal areas NA1, NA2, NA3, and NA4 are examples of the first normal area, the second normal area, the third normal area, and the fourth normal area, respectively. Also, the conveyance amount TL of the sheet conveyance T1 is an example of the first conveyance amount, and the TL of the sheet conveyance T2 is an example of the second conveyance amount. The end pressing head position is an example of a specific position, and the pressing reference position RL is an example of a reference position.

[0090] B. Second Example Fig. 10 is a first explanatory diagram of multi-pass printing. Fig. 10 shows an example of a print image PIb printed on paper M, and head positions for multiple partial printings of the print image PIb. The print image PIb includes multiple normal regions (for example, non-hatched regions NB0-NB4 in Fig. 10) and multiple edge regions (for example, hatched regions SB0-SB3 in Fig. 10).

[0091] In the first embodiment, the normal areas (for example, NA0 to NA4 in FIG. 5) are each printed in a single partial printing (so-called multi-pass printing). That is, in the first embodiment, multiple raster lines aligned in the transport direction AR within one normal area are printed in a single partial printing.

[0092] In contrast, in the second embodiment, each normal area is printed by two partial prints. Two partial prints for printing one normal area are also called partial print sets. For example, the normal area NB0 in FIG. 6 is printed by a partial print set executed at head positions P0a and P0b. Similarly, the normal areas NB1, NB2, NB3, and NB4 are printed by a partial print set executed at head positions P1a and P1b, a partial print set executed at head positions P2a and P2b, a partial print set executed at head positions P3a and P3b, and a partial print set executed at head positions P4a and P4b, respectively. As a result, the print resolution in the transport direction AR of the print image PIb in the second embodiment is twice that of the print image PI in the first embodiment.

[0093] In the second embodiment, among the multiple raster lines aligned in the transport direction AR in the normal area, two adjacent raster lines 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.

[0094] Sheet transports T1a, T2a, T3a, and T4a are sheet transports performed between two partial prints that constitute a partial print set. The transport amount of sheet transports T1a, T2a, T3a, and T4a is a small transport amount ΔTL, for example, a transport amount for an odd number of raster lines (three in this embodiment). 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 (one in this embodiment) on the downstream side (+Y side) that correspond to the small 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 (one in this embodiment) on the upstream side (-Y side) that correspond to the small transport amount ΔTL.

[0095] Sheet transport T0b is a sheet transport performed after a partial print set performed at head positions P0a and P0b. Sheet transports T1b, T2b, and T3b are sheet transports performed after a partial print set performed at head positions P1a and P1b, after a partial print set performed at head positions P2a and P2b, and after a partial print set performed at head positions P3a and P3b, respectively.

[0096] The region RB0 printed by the partial printing set executed at head positions P0a and P0b includes a normal region NB0 and an end region SB0 upstream (-Y side) of the normal region NB0. The region RB1 printed by the partial printing set executed at head positions P1a and P1b includes a normal region NB1, an end region SB0 downstream (+Y side) of the normal region NB1, and an end region SB1 upstream (-Y side) of the normal region NB1. The region RB2 printed by the partial printing set executed at head positions P2a and P2b includes a normal region NB2, an end region SB1 downstream (+Y side) of the normal region NB2, and an end region SB2 upstream (-Y side) of the normal region NB2. The region RB3 printed by the partial printing set performed at head positions P3a and P3b includes the normal region NB3, an end region SB2 downstream (+Y side) of the normal region NB3, and an end region SB3 upstream (-Y side) of the normal region NB3. The region RB4 printed by the partial printing set performed at head positions P4a and P4b includes the normal region NB4 and an end region SB3 downstream (+Y side) of the normal region NB4.

[0097] Each raster line in the edge region is printed in two partial print sets. For example, in each raster line in the edge region SB1 in Fig. 10, dots are formed in both one partial print constituting a partial print set performed at head positions P1a and P1b, and one partial print constituting a partial print set performed at head positions P2a and P2b. The length Hb (Fig. 10) of the edge region in the transport direction AR is, for example, 3 to several tens, and is 8 in this embodiment, in units of the number of nozzles (number of raster lines) of the partial print set.

[0098] In this embodiment, of the multiple partial print sets, the partial print sets except for the last partial print set are performed in a state in which the paper M is pressed down by the pressing member 146. The last partial print set is performed in a state in which the paper M is not pressed down by the pressing member 146. Subsequent partial printing that constitutes the partial print set before the last is performed at the end pressing head position. In the example of FIG. 10, the partial print set before the last is a partial print set performed at head positions P3a and P3b. Therefore, head position P3b is the end pressing head position.

[0099] In the second embodiment, when the first partial print set that prints a plurality of raster lines including a raster line located upstream of the holding reference position RLb (FIG. 10) is a target partial print set, the next partial print set after the target partial print set is a partial print set that includes partial printing performed at the end holding head position. For this reason, the transport amount TLb of the sheet transport after the target partial print set is determined so that the subsequent partial printing constituting the next target partial print set is performed at the end holding head position. For this reason, it is shorter than the transport amount TLb of the sheet transport after the other partial print sets. And, in the partial print set that includes partial printing performed at the end holding head position, the nozzle shift amount NSb is greater than 0.

[0100] 10, the transport amount TLb of the sheet transport T2b after the partial print set executed at the head positions P2a and P2b is shorter than the sheet transports T0b, T1b, and T3b. The nozzle shift amount NSb of the partial print set executed at the head positions P3a and P3b is a value greater than 0 according to the excess amount VOb.

[0101] In the example of FIG. 10, the CPU 210 determines the target transport amount TLb of the sheet transport T2b so that the head position P3b of the subsequent partial printing constituting the next partial printing set becomes the end pressing head position. As in the first embodiment, when the target transport amount of the sheet transport T2b is equal to or greater than the reference value TLbth, the CPU 210 sets the shortening amount VSb at the head positions P2a and P2b to O and does not provide upstream unused nozzles at the head positions P2a and P2b (FIG. 10). Then, as described later, when the target transport amount of the sheet transport T2b is smaller than the reference value TLbth, the CPU 210 sets the shortening amount VSb at the head positions P2a and P2b to a value greater than 0 and provides upstream unused nozzles at the head positions P2a and P2b. This makes it possible to prevent the length of the transport direction AR of the area RB3 printed in the partial printing set executed at the head positions P3a and P3b from becoming excessively short in the second embodiment as well. As a result, the length of the end areas SB2 and SB3 in the transport direction AR can be secured by the number of nozzles Hb that should be secured.

[0102] 10, the position of head position P2b in the transport direction AR is relatively far from the position of head position P3a in the transport direction AR, so the transport amount TLb is greater than the reference value TLbth and the excess amount VO is smaller than the upper limit value NSbmax. Therefore, the nozzle shift amount NSb of head positions P3a and P3b is smaller than the upper limit value NSbmax. In addition, the shortening amount VSb of head positions P2a and P2b is set to 0, and no unused upstream nozzles are provided at head positions P2a and P2b.

[0103] Here, as in the first embodiment, the position of the head position P2b in the transport direction AR varies due to a margin on the downstream side (+Y side in FIG. 10) of the print image PIb, and so the position of the head position P2b in the transport direction AR and the position of the head position P3a in the transport direction AR may be close to each other. Below, the embodiment and the comparative example will be described while comparing them. FIG. 11 is a second explanatory diagram of multi-pass printing. FIG. 11 is an explanatory diagram of printing in the comparative example. FIG. 12(A) shows an explanatory diagram similar to FIG. 10, in which the position of the head position P2b in the transport direction AR and the position of the head position P3a in the transport direction AR are close to each other. FIG. 12(A) shows an explanatory diagram of the comparative example, in which the position of the head position P2b in the transport direction AR and the position of the head position P3a in the transport direction AR are close to each other.

[0104] In this embodiment shown in Fig. 11A, the transport amount TLb of the sheet transport T2b after partial printing performed at head position P2b is smaller than the reference value TLbth, and the excess amount VO is larger than the upper limit value NSbmax. For this reason, in the example shown in Fig. 11A, the nozzle shift amount NSb at head positions P3a and P3b is set to the upper limit value NSbmax. In addition, the shortening amount VSb at head positions P2a and P2b is set to a value larger than O, and upstream unused nozzles are provided at head positions P2a and P2b.

[0105] FIG. 11B shows an enlarged view of the area AAb enclosed by a dashed line in FIG. 11A. In FIG. 11B, the black circle, square, and white circle shown inside the head position respectively indicate the nozzles NZ that print the end area, the nozzles NZ that print the normal area, and the nozzles NZ that are not used. As shown in FIG. 11B, the head positions P2a and P2b are provided with a nozzle group NUb of upstream unused nozzles with a shortening amount VSb. The nozzle group NG2b at the head positions P2a, P2b, P3a, and P3b is a nozzle group that prints the end area SB2. The nozzle group NG3b at the head positions P3a, P3b, P4a, and P4b is a nozzle group that prints the end area SB3. The nozzle shift amount NSb for head positions P3a and P3b is set to the upper limit value NSbmax, and the nozzle group NUb of the upstream unused nozzles is provided at head positions P2a and P2b, so that the length in the transport direction AR of the area RB3 printed by the partial print set executed at head positions P3a and P3b does not become excessively short. This means that the length in the transport direction AR of nozzle groups NG2b and NG3b is secured to the number of nozzles Hb (8 in this embodiment) each.

[0106] In the comparative example, the concepts of the upper limit value NSbmax of the nozzle shift amount NSb and the shortening amount VSb of the used nozzle are not introduced. For this reason, an upper limit value is not set for the nozzle shift amount NSb at the head positions P3a and P3b, and upstream unused nozzles are not provided at the head positions P2a and P2b. In the comparative example of FIG. 12(A), the conveyance amount TLb of the sheet conveyance T2b after partial printing performed at the head position P2b is smaller than the reference value TLbth, and the excess amount VO is larger than the upper limit value NSbmax. Even in this case, in the comparative example, the nozzle shift amount NSb at the head positions P3a and P3b is set to the excess amount VO, and upstream unused nozzles are not provided at the head positions P2a and P2b.

[0107] For this reason, the length in the transport direction AR of the region RB3 printed by the partial print set executed at head positions P3a and P3b becomes excessively short. As a result, the length in the transport direction AR of the end region SB2 is secured for the number of nozzles Hb that should be secured, but the length in the transport direction AR of the end region SB3 is not secured for the number of nozzles Hb.

[0108] FIG. 12B shows an enlarged view of the area AAbx surrounded by a dashed line in FIG. 12A. In FIG. 12B, as in FIG. 11B, black circles, squares, and white circles respectively indicate nozzles NZ that print the end area, nozzles NZ that print the normal area, and unused nozzles NZ. The nozzle group NG2bx at head positions P2a, P2b, P3a, and P3b is a nozzle group that prints the end area SB2. The nozzle group NG3bx at head positions P3a, P3b, P4a, and P4b is a nozzle group that prints the end area SB3. The nozzle group NG2bx includes nozzles in the transport direction AR for the number of nozzles Hb (8 in this embodiment), but the nozzle group NG3bx includes only nozzles in the transport direction AR for the number of nozzles Hbx (4 in FIG. 12B), which is less than the number of nozzles Hb.

[0109] As can be seen from the above explanation, in the comparative example, the length of the edge region SB3 in the transport direction AR cannot be sufficiently secured, so printing of the edge region SB3 cannot be performed appropriately. Therefore, in the comparative example, banding may be noticeable in the edge region SB3 of the printed image PIb. In contrast, in this embodiment, the length of the edge region SB3 in the transport direction AR can be sufficiently secured, so printing of the edge region SB3 can be performed appropriately and banding in the printed image PIb can be suppressed from being noticeable.

[0110] As can be seen from the above description, the two partial printings at the head positions P1a and P1b in this embodiment are an example of the first partial printing, the two partial printings at the head positions P2a and P2b are an example of the second partial printing, the two partial printings at the head positions P3a and P3b are an example of the third partial printing, and the two partial printings at the head positions P4a and P4b are an example of the fourth partial printing. Also, the end regions SB1, SB2, SB3, and SB4 are examples of the first end region, the second end region, the third end region, and the fourth end region, respectively. The normal regions NB1, NB2, NB3, and NB4 are examples of the first normal region, the second normal region, the third normal region, and the fourth normal region, respectively. Also, the conveyance amount TLb of the sheet conveyance T1b is an example of the first conveyance amount, and the TLb of the sheet conveyance T2b is an example of the second conveyance amount.

[0111] C. Modifications (1) In the second embodiment described above, one partial print set is composed of two partial prints. Alternatively, one partial print set may be composed of two or more partial prints, for example, three or four partial prints. In general, one partial print set may be composed of N partial prints (N is an integer equal to or greater than 2). In this case, of the multiple raster lines aligned in the transport direction in each normal area, adjacent N raster lines are each printed by different partial prints included in one partial print set.

[0112] (2) 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 print data conversion 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 for 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 for all sheet conveyances is determined, the partial print data and the conveyance amount data may be output.

[0113] (3) As the print medium, instead of paper M, other media, such as OHP film, CD-ROM, or DVD-ROM, may be used.

[0114] (4) 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 partial print data and carry amount data to the printer 200 as a print execution unit, thereby causing the printer 200 to execute printing.

[0115] (5) 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 carry 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.

[0116] (6) 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.

[0117] 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]

[0118] 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, Ha...number of nozzles, Hb...number of nozzles, Hbx...number of nozzles, Hx...number of nozzles, LP...low support member, LP...each 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 alternately execute partial printing, in which the print head forms the dots, and conveying the print medium by the conveying unit, multiple times to print a print image; When causing the print execution unit to print the print image, the control device performing a first partial printing, which is the partial printing performed in a state in which the print medium faces the opposing member, one or more times; After the first portion printing is performed one or more times, the print medium is conveyed a first conveyance amount; After the first transport amount is transported, a second partial printing is performed one or more times, the second partial printing being the partial printing performed in a state where the print medium faces the opposing member; After the second portion printing is executed one or more times, the print medium is transported a second transport amount that is smaller than the first transport amount; after conveying the second conveyance amount, a third partial printing is performed one or more times, the third partial printing being the partial printing that is performed 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 on an upstream side in the conveyance direction of the print medium faces the opposing member; After the third portion printing is performed one or more times, the print medium is transported; Thereafter, a fourth partial printing is performed one or more times, the fourth partial printing being the partial printing performed in a state where the print medium is not opposed to the opposing member; the first region printed by the first 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 printed by 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 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 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 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, The control device includes: If the second carry amount is equal to or greater than a reference amount, the nozzle range to be used in the second partial printing is determined to be the first range, which is the same nozzle range to be used in the first partial printing; If the second carry amount is smaller than the reference amount, the nozzle range to be used in the second partial printing is determined to be a second range smaller than the first range; the use nozzle range is a range in the transport direction that is used in the partial printing among the plurality of nozzles, the second range is a range that does not include a predetermined range that is a part of the first range on the upstream side in the transport direction, A printing device, wherein an image within an area corresponding to the predetermined range in the second partial printing is printed in the third partial printing.

2. 2. The printing device according to claim 1, When the second carry amount is smaller than the reference value, the control device increases the predetermined range as the second carry amount decreases.

3. 3. The printing device according to claim 1, When the second transport amount is smaller than the reference amount, the control device determines the predetermined range according to a length of the first end region in the transport direction.

4. The printing device according to any one of claims 1 to 3, The number of times of the first partial printing, the second partial printing, the third partial printing, and the fourth partial printing is one, a plurality of first raster lines in the first normal region that are aligned in the transport direction are printed in one first partial printing, a plurality of second raster lines in the second normal region that are aligned in the transport direction are printed in one second partial printing, a plurality of third raster lines in the third normal region that are aligned in the transport direction are printed in one third partial printing, a printing device in which a plurality of fourth raster lines in the fourth normal area that are aligned in the transport direction are printed in one fourth partial printing.

5. 5. The printing device according to claim 4, The control device determines the predetermined range to be equal to or greater than a value obtained by subtracting the second transport amount from a length of the first end region in the transport direction.

6. The printing device according to any one of claims 1 to 3, the first partial printing, the second partial printing, the third partial printing, and the fourth partial printing are each performed N times (N is an integer equal to or greater than 2); 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, A printing device, wherein, among a plurality of fourth raster lines within the fourth normal area that are aligned in the transport direction, N adjacent fourth raster lines are printed by the fourth partial printing that are different from each other.

7. The printing device according to any one of claims 1 to 6, the print image includes a plurality of raster lines aligned in the transport direction, The control device includes: generating print data indicating the print image using input image data, the print data including a plurality of raster data corresponding to the plurality of raster lines; causing the print execution unit to print the print image using the print data; The control device includes: when outputting the print data to the print execution unit, the plurality of raster lines are sequentially processed from the downstream side to the upstream side in the transport direction; determining, as the first carry amount, a carry amount of the printing medium after the partial printing in which a plurality of raster lines among the plurality of raster lines, which does not include a raster line that is on the upstream side of a reference position in the carry direction, are printed; determining, as the second carry amount, a carry amount of the printing medium after a first partial printing of a plurality of raster lines including a raster line that is upstream of the reference position in the carry direction, among the plurality of raster lines; determining the active nozzle range for the first partial print to be either the first range or the second range; A printing device, wherein the reference position is a position determined based on the specific position and is a position on the printing medium in the transport direction.

8. The printing device according to any one of claims 1 to 7, 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.

9. 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, performing a first partial printing, which is the partial printing performed in a state in which the print medium faces the opposing member, one or more times; After the first portion printing is performed one or more times, the print medium is conveyed a first conveyance amount; After the first transport amount is transported, a second partial printing is performed one or more times, the second partial printing being the partial printing performed in a state where the print medium faces the opposing member; After the second portion printing is executed one or more times, the print medium is transported a second transport amount that is smaller than the first transport amount; after conveying the second conveyance amount, a third partial printing is performed one or more times, the third partial printing being the partial printing that is performed 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 on an upstream side in the conveyance direction of the print medium faces the opposing member; After the third portion printing is performed one or more times, the print medium is transported; Thereafter, a fourth partial printing is performed one or more times, the fourth partial printing being the partial printing performed in a state where the print medium is not opposed to the opposing member; the first region printed by the first 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 printed by 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 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 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 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, The computer program comprises: if the second carry amount is equal to or greater than a reference value, determining an active nozzle range for the second partial printing to be a first range, which is the same active nozzle range as that for the first partial printing; if the second carry amount is smaller than the reference value, determining the nozzle range to be used in the second partial printing to be a second range smaller than the first range; The above-mentioned program is executed on the computer. the use nozzle range is a range in the transport direction that is used in the partial printing among the plurality of nozzles, the second range is a range that does not include a predetermined range that is a part of the first range on the upstream side in the transport direction, A computer program product, wherein an image within an area corresponding to the predetermined range in the second partial printing is printed in the third partial printing.

Images