Printing device and computer program

Abstract

To reduce a rewinding amount of a printing medium wound in a roll shape.SOLUTION: A printer comprises: a housing; a print head disposed in the housing; a mounting part on which a roll body is detachably mounted; a conveyance part which conveys a printing medium in a conveying direction along a conveyance path including an upstream path from the mounting part to the print head; and a cutter which cuts the printing medium at a specified position of the upstream path. The roll body is a printing medium wound in a sheet shape. The conveyance part comprises a holding part disposed at a position between the cutter and the print head in the upstream path. The holding part holds the printing medium which is in a state of being wavily deformed along a direction perpendicular to the conveying direction.SELECTED DRAWING: Figure 2

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] Printers that print on roll paper are known. For example, the inkjet recording device disclosed in Patent Document 1 includes a sheet cutting device located downstream of the recording head on the transport path. The sheet cutting device cuts the printed portion of the roll paper. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-86235 Summary of the Invention [Problem to be solved by the invention]

[0004] When removing roll paper from the recording device's housing, the unwound leading edge of the roll paper may be rewound to prevent it from coming into contact with the housing and bending. In this case, with the above technology, the sheet is cut downstream of the recording head on the transport path, leaving a relatively long unwound leading edge of the roll paper. As a result, with the above technology, the amount of roll paper rewound is large, and rewinding can take a long time.

[0005] This specification discloses a technique for reducing the amount of unwinding of a print medium wound in a roll. [Means for solving the problem]

[0006] The techniques disclosed in this specification can be implemented in the following application examples.

[0007] [Application Example 1] A printing device comprising: a housing; a print head provided within the housing; a mounting unit to which a roll body is detachably attached, the roll body being a wound sheet-like printing medium; a transport unit that transports the printing medium in a transport direction along a transport path that includes an upstream path from the mounting unit to the print head; and a cutter that cuts the printing medium at a specific position on the upstream path, wherein the transport unit comprises a holding unit that is positioned on the upstream path between the cutter and the print head, and the holding unit holds the printing medium in a wavy state that is deformed along a direction perpendicular to the transport direction.

[0008] With this configuration, the cutter cuts the print medium at a specific location on the upstream path from the roll mounting portion to the print head, making the distance from the mounting portion to the cutting position relatively short, which reduces the amount of rewinding required for the roll. [Application example 2] The printing device according to Application Example 1, the print head has 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 ejects ink onto the print medium to form dots on the print medium; the printing device further includes a control unit that performs multi-pass printing in which partial printing, in which the print head forms the dots, and transporting the print medium by the transport unit are performed alternately a plurality of times, thereby printing a plurality of consecutive raster lines in the transport direction by the partial printing a plurality of times; The control unit a first transport operation for transporting the print medium and the partial printing operation after the first transport operation are performed a plurality of times; a second transport operation that transports the print medium by a transport amount smaller than that of the first transport operation, and the partial printing that follows the second transport operation; a third transport operation that transports the print medium by a transport amount greater than that of the first transport operation, and the partial printing that follows the third transport operation; the third transport operation transports the printing medium from a start position where an upstream end of the printing medium in the transport direction is held by the holding unit to an end position where the upstream end is not held by the holding unit; the control unit adjusts at least one of the number of times the second transport operation is performed and the transport amount of the second transport operation so that the upstream edge of the print medium is positioned within a specific range at the start position of the third transport operation; The specific range is a range in the transport direction that is determined with respect to the holding unit. [Application example 3] The printing device according to Application Example 2, The control unit adjusts the number of times the second transport operation is performed so that the upstream edge of the print medium is positioned within a specific range at the start position of the third transport operation. [Application example 4] The printing device according to Application Example 3, The control unit When the upstream edge of the print medium is at a first position upon completion of the first transport operation, the second transport operation is performed N times (N is an integer greater than or equal to 1); A printing device that performs the second transport operation M times (M is an integer satisfying M>N) when the upstream end of the printing medium is at a second position upstream of the first position upon completion of the first transport operation. [Application example 5] The printing device according to Application Example 4, A printing device, wherein the carry amount of the N second transport operations is the same as the carry amount of the M second transport operations. [Application Example 6] The printing device according to Application Example 5, When the control unit executes the M number of second transport operations, the control unit adds (MN) number of second transport operations after the N number of second transport operations, A printing device wherein the plurality of nozzles used in the partial printing performed after each of the additional (MN) second transport operations are the same as the plurality of nozzles used in the partial printing performed after the last transport operation of the N second transport operations. [Application Example 7] The printing device according to Application Example 2, The control unit adjusts the transport amount of the second transport operation so that the upstream edge of the print medium is positioned within a specific range at the start position of the third transport operation. [Application Example 8] The printing device according to Application Example 7, The control unit When the upstream edge of the printing medium is at a first position upon completion of the first transport operation, a transport amount of the specific second transport operation is set to a first amount; A printing device that sets the transport amount of the specific second transport operation to a second amount smaller than the first amount when the upstream end of the printing medium is at a second position downstream of the first position at the completion of the first transport operation. [Application Example 9] The printing device according to Application Example 8, a control unit that, when setting the transport amount of the specific second transport operation to the second amount, reduces the number of raster lines printed in the partial printing performed after the second transport operation compared to when setting the transport amount of the specific second transport operation to the first amount. [Application Example 10] The printing device according to any one of Application Examples 7 to 9, the multi-pass printing is a printing method in which a recording rate of at least a part of the partial printing performed multiple times to print a specific area is changed according to a position in the transport direction, When adjusting the carry amount of the second transport operation, the control unit adjusts the recording rate of the partial printing after the second transport operation in accordance with the adjustment of the carry amount. [Application Example 11] The printing device according to any one of Application Examples 1 to 10, the holding section includes a plurality of ribs positioned at different positions in a specific direction perpendicular to the transport direction, the plurality of ribs supporting the print medium from below, and a plurality of pressing members positioned at different positions in the specific direction, the plurality of pressing members pressing the print medium from above, A printing device, wherein the positions of each of the plurality of pressing members in the specific direction are located between two of the plurality of ribs that are adjacent to each other in the specific direction.

[0009] 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 explanation of the drawings]

[0010] [Figure 1] FIG. 2 is a block diagram showing the configuration of a printer 200 according to the embodiment. [Figure 2] FIG. 1 is a diagram showing a schematic configuration of a printing mechanism 100. [Figure 3] FIG. 1 is a diagram showing a schematic configuration of a printing mechanism 100. [Figure 4] FIG. 2 is a diagram showing the configuration of a print head 110. [Figure 5] FIG. 14 is a perspective view of a paper tray 145 and a plurality of pressing members 146. [Figure 6] 10 is a flowchart of a printing process. [Figure 7] FIG. 1 is a first explanatory diagram of printing in the first embodiment. [Figure 8] FIG. 10 is an explanatory diagram of the recording rate of partial printing. [Figure 9] FIG. 2 is a second explanatory diagram of printing in the first embodiment. [Figure 10] FIG. 10 is a third explanatory diagram of printing in the first embodiment. [Figure 11] FIG. 4 is a fourth explanatory diagram of printing in the first embodiment. [Figure 12] FIG. 10 is an explanatory diagram of printing in a comparative example. [Figure 13] FIG. 5 is a fifth explanatory diagram of printing in the first embodiment. [Figure 14] FIG. 6 is a sixth explanatory diagram of printing in the first embodiment. [Figure 15] 10 is a flowchart of a print data output process. [Figure 16] FIG. 10 is a first explanatory diagram of printing in the second embodiment. [Figure 17] FIG. 10 is a second explanatory diagram of printing in the second embodiment. [Figure 18] FIG. 10 is a third explanatory diagram of printing in the second embodiment. [Figure 19] FIG. 4 is a fourth explanatory diagram of printing in the second embodiment. [Figure 20] FIG. 10 is an explanatory diagram of the recording rate of partial printing in the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] A. First Example: A-1: Printer 200 Configuration Next, the embodiment will be described based on an example. Fig. 1 is a block diagram showing the configuration of a printer 200 according to the example.

[0012] The printer 200 includes, for example, a printing 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 RAM, an operation unit 260 such as buttons or a touch panel for acquiring user operations, 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 communicably connected to an external device, for example, a user's terminal device 300, via the communication unit 280.

[0013] The volatile storage device 230 provides a buffer area 231 that temporarily stores 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 stored in the non-volatile storage device 220 when the printer 200 is shipped. Alternatively, the computer program PG may be provided in a form downloaded from a server or 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. In this way, the CPU 210 controls the printing mechanism 100 to print an image on a printing medium (e.g., paper).

[0014] The printing mechanism 100 is capable of forming 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, a conveying unit 140, and a sheet cutting unit 150.

[0015] Fig. 2 is a diagram showing a schematic configuration of the printing mechanism 100. Fig. 3 is an enlarged view of the vicinity of the print head 110 in Fig. 2. As shown in Fig. 2, the elements 110 to 150 of the printing mechanism 100 are housed in a housing 1 of the printer 200. The X and Y directions in Fig. 2 are horizontal directions, and the Z direction is vertical.

[0016] 2, the printing mechanism 100 further includes a paper feed tray 5, a roll mounting unit 11 provided inside the paper feed tray 5, and a paper output tray 6 to which printed sheets are output. The paper feed tray 5 has, for example, a box shape that opens upward, and is detachable from the lower part of the housing 1. The paper output tray 6 is formed by the side wall at the front of the upper part of the housing 1, and can be opened and closed relative to the housing 1.

[0017] A roll R, which is obtained by winding a long length of paper M into a cylindrical shape, is detachably mounted on the roll mounting section 11. The roll R is mounted in a recess 11x formed in the roll mounting section 11 so that its axis Rx is parallel to the X direction in FIG. 2. When mounted on the roll mounting section 11, the roll R is supported by rollers 14 and 15 so as to be rotatable in a rotation direction B about the axis Rx. A long hole 11y extending in the X direction is formed in the lower part of the roll mounting section 11.

[0018] The conveying section 140 conveys the paper M unwound from the roll body R along a conveying path from the long hole 11y of the roll mounting section 11, through between the print head 110 and the paper tray 145 (described later), and to the paper output tray 6.

[0019] The conveying section 140 includes, from the upstream side to the downstream side of the conveying path, a feeding roller 141, a pair of intermediate rollers 142, a pair of conveying rollers 143, a pair of paper ejection rollers 144, a paper tray 145, and guide members 147 and 148.

[0020] The feed roller 141 is pivotally supported at the tip of the arm 3. The arm 3 is rotatably supported on a support shaft 3x, and is biased so that the feed roller 141 approaches the bottom surface of the paper feed tray 5. When the roll R is attached to the roll attachment section 11, the feed roller 141 is driven by a paper feed motor (not shown) and transports the paper M unwound from the roll R.

[0021] The intermediate roller pair 142, the conveying roller pair 143, and the paper discharge roller pair 144 each include a drive roller driven by a conveying motor (not shown) and a driven roller that rotates in accordance with the rotation of the drive roller. These roller pairs sandwich the paper M and convey the paper M along the conveying path.

[0022] Guide member 147 is disposed on the conveying path between feed roller 141 and intermediate roller pair 142. Guide member 148 is disposed on the conveying path between intermediate roller pair 142 and conveying roller pair 143. These guide members guide paper M along the conveying path.

[0023] As shown in FIG. 3, 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. 3). 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 relative to the paper M in the main scanning direction.

[0024] 3, near the print head 110, the transport unit 140 holds the paper M between the print head 110 and the paper tray 145, and transports the paper M in a transport direction AR (+Y direction in FIG. 3) that intersects with the main scanning direction. Hereinafter, the upstream side (-Y side) of the transport direction AR will also be simply referred to as the upstream side, and the downstream side (+Y side) of the transport direction AR will also be simply referred to as the downstream side.

[0025] 3, the above-mentioned conveying roller pair 143 holds the paper M upstream (-Y side) of the print head 110, and the above-mentioned paper discharge roller pair 144 holds the paper M downstream (+Y side) of the print head 110. The paper platform 145 is located between the conveying roller pair 143 and the paper discharge roller pair 144, and is positioned opposite the nozzle forming surface 111 of the print head 110.

[0026] The head driving unit 120 (FIG. 1) supplies a driving signal to the print head 110 to drive the print head 110 while the main scanning unit 130 is performing a main scan of 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.

[0027] FIG. 4 is a diagram showing the configuration of the print head 110 as seen from the -Z side (the bottom side in FIG. 2). As shown in FIG. 4, the nozzle forming surface 111 of the print head 110 is formed with multiple nozzle rows consisting of multiple nozzles, i.e., nozzle rows NC, NM, NY, and NK that eject the above-mentioned C, M, Y, and K inks. Each nozzle row includes multiple nozzles NZ aligned along the transport direction AR. The multiple nozzles NZ are positioned at different positions in the transport direction AR (+Y direction) and aligned along the transport direction AR at a predetermined nozzle spacing NT. The nozzle spacing NT is the length in the transport direction AR between two nozzles NZ adjacent to each other in the transport direction AR among the multiple nozzles NZ. Of the nozzles constituting these nozzle rows, the nozzle NZ located most upstream (on the -Y side) is also referred to as the most upstream nozzle NZu. Furthermore, of these nozzles NZ, the nozzle NZ located most downstream (on the +Y side) is referred to as 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 referred to as the nozzle length D. The nozzle length D is expressed in units of the number of nozzles included in each nozzle row. Note that in an actual product, of 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 along the nozzle length D. In this embodiment, the nozzles NZ used for printing are referred to as usable nozzles.

[0028] The nozzle rows NC, NM, NY, and NK are positioned differently in the main scanning direction (X direction in FIG. 4), and overlap each other in the transport direction AR (Y direction in FIG. 4). For example, in the example of FIG. 4, the nozzle row NK is disposed in the +X direction of the nozzle row NY that ejects Y ink.

[0029] The sheet cutting unit 150 is disposed between the guide member 147 and the pair of intermediate rollers 142 on the conveyance path. The sheet cutting unit 150 is configured to cut the paper M at a specific position Cp on the upstream path TR from the roll mounting unit 11 to the print head 110. The sheet cutting unit 150 includes a cutter 151 and a scanning mechanism 152 to which the cutter 151 is attached. The cutter 151 is configured to pinch the paper M between two rotary blades 151a and 151b during cutting. The scanning mechanism 152 is a mechanism that reciprocates the cutter 151 in the X direction using the power of a drive motor (not shown) under the control of the CPU 210. When not in use, the scanning mechanism 152 positions the cutter 151 at a position different from the range in the X direction in which the paper M is located. During cutting, the scanning mechanism 152 moves the cutter 151 so as to traverse the range in the X direction in which the paper M is located. This cuts the paper M.

[0030] In this embodiment, the sheet cutting section 150 is located upstream of the print head 110, so the sheet cutting section 150 cuts the paper M before printing on the paper M is completed.

[0031] The transport section 140 will be further described with reference to Figure 5. Figure 5 is a perspective view of a paper tray 145 and a plurality of pressing members 146. Figure 5(A) shows a state in which no paper sheet M is held, and Figure 5(B) shows a state in which a paper sheet M is held. The paper tray 145 includes a plurality of high support members HP that are positioned differently in the X direction, a plurality of low support members LP that are positioned differently in the X direction, and a flat plate BB.

[0032] 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 pair of transport rollers 143. The downstream end (+Y side) of the flat plate BB is located near the pair of paper discharge rollers 144.

[0033] As shown in FIG. 5(A), multiple high support members HP and multiple low support members LP are arranged alternately along the X direction on the flat plate BB. That is, each low support member LP is disposed between two high support members HP adjacent to that 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.

[0034] The multiple presser members 146 are arranged on the +Z side of the multiple low support members LP. The X-direction positions of the multiple presser members 146 are different from one another and are the same as the X-direction positions of the multiple low support members LP. That is, the X-direction position of each presser member 146 is located between two high support members HP that are adjacent to that presser member 146 in the X-direction. The ends of the multiple presser members 146 are plate-shaped members that extend along the Y-direction. The Y-direction positions of the multiple presser members 146 are upstream (-Y side) of the print head 110 and downstream (+Y side) of the sheet cutting section 150 and the conveying roller pair 143.

[0035] As shown in FIG. 5B, when the paper M is being transported, the multiple high support members HP and the multiple low support members LP face the surface Mb opposite the printing surface and support the paper M from the surface Mb side. The multiple presser 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 presser members 146 hold the paper M in a wavy state along the X direction (FIG. 5B). The paper M is then transported in the transport direction (-Y direction) in a wavy state at a position facing the nozzle forming surface 111 of the print head 110. Deforming the paper M in a wavy state increases the rigidity of the paper M against deformation along the Y direction. As a result, the paper M is warped along the Y direction, preventing the paper M from lifting off the paper stand 145 toward the print head 110 or drooping toward the paper stand 145. If the paper M lifts up or sags, the position of the dots formed may shift, which may cause a deterioration in the quality of the printed image, for example, a deterioration in image quality due to banding. Furthermore, if the paper M lifts up, the paper may come into contact with the print head 110 and become soiled. In particular, in this embodiment, the paper M is unwound from the roll R, and therefore is prone to bending, which makes the paper M prone to lifting up or sagging. For this reason, the effect of deforming the paper M into a wavy shape is significant.

[0036] As shown in FIG. 3, when the upstream edge Me of the sheet M being conveyed (the edge on the -Y side cut by the cutter 151) is located in the prohibited range NGA, the sheet M is more likely to become soiled due to the sheet M floating up. The prohibited range NGA is the range in the Y direction from position Yu to position Ym in FIG. 3. Here, as shown in FIG. 3, the state in which the sheet M is held only by the pair of sheet discharge rollers 144 and is not pressed down by the presser member 146 is also referred to as a cantilevered state. In the cantilevered state, the length Ly in the Y direction of the portion of the sheet M that is upstream (on the -Y side) of position Yd where the sheet M is held by the pair of sheet discharge rollers 144 is also referred to as the cantilevered sheet length Ly. In the cantilevered state, the longer the cantilevered sheet length Ly, the more likely the upstream edge Me of the sheet M is to float up, and the more likely the sheet M is to become soiled.

[0037] The position Yu of the upstream end of the prohibited range NGA is slightly upstream (towards the -Y side) of the downstream (+Y side) end of the pressing member 146. When the upstream end Me of the paper M is located upstream (towards the -Y side) of position Yu, the paper M is sufficiently pressed down by the pressing member 146. In this state, the paper M is less likely to become soiled.

[0038] The downstream end position Ym of the prohibited range NGA is near the center of the range in the Y direction in which the print head 110 is located. When the upstream end Me of the paper M is located downstream (+Y side) of position Ym, the paper M is in a cantilevered state, held only by the pair of paper discharge rollers 144, but the cantilevered paper length Ly described above is sufficiently short. In this state, the paper M is less likely to become soiled.

[0039] In contrast, when the upstream edge Me of the sheet M is located in the prohibited range NGA, the upstream edge Me of the sheet M is located downstream (+Y side) of position Yu. In this state, the sheet M is not pressed down by the presser member 146, or only a small portion near the upstream edge Me is pressed down, and the upstream edge Me is likely to come off the presser member 146. Furthermore, when the upstream edge Me of the sheet M is located in the prohibited range NGA, the upstream edge Me of the sheet M is located upstream (-Y side) of position Ym. In this state, the cantilevered sheet length Ly described above is long. For this reason, when the upstream edge Me of the sheet M is located in the prohibited range NGA, as described above, staining of the sheet M is likely to occur. The prohibited range NGA is determined experimentally, for example, by actually repeating a large number of printing runs while changing the position of the upstream edge Me of the sheet M.

[0040] In the printing process of this embodiment, as will be described in detail later, in order to prevent the paper M from becoming soiled during partial printing, measures have been taken to prevent partial printing from being performed when the upstream end Me of the paper M is located within the prohibited range NGA.

[0041] A-3. Printing process The CPU 210 (FIG. 1) of the printer 200 executes printing processing based on a printing instruction input by a user via the operation unit 260. The printing instruction includes a specification of image data indicating the image to be printed. FIG. 6 is a flowchart of the printing processing. In S110, the CPU 210 acquires the image data specified by the printing instruction from the non-volatile storage device 220. Alternatively, the printing instruction and image data may be acquired from the terminal device 300. The acquired image data may be image data in various formats, such as JPEG-compressed image data or image data written in a page description language.

[0042] In S120, the CPU 210 performs 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 containing RGB values ​​for each pixel. The RGB values ​​are, for example, color values ​​in the RGB color system containing three component values: red (R), green (G), and blue (B).

[0043] In S130, the CPU 210 converts the RGB image data into print data. Specifically, the CPU 210 performs color conversion and halftone processing on the RGB image data. The color conversion process converts the RGB values ​​of multiple pixels contained in the RGB image data into CMYK values. The CMYK values ​​are color values ​​in the CMYK color system, including component values ​​corresponding to the inks used in printing (in this embodiment, C, M, Y, and K component values). The color conversion process is performed, for example, by referencing a known lookup table that defines the correspondence between RGB values ​​and CMYK values. The halftone process converts 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 CMYK color component. The value of each pixel in the dot data represents the dot formation state in two gradations, for example, "no dot" and "dot," or in four gradations, for example, "no dot," "small," "medium," and "large." The halftone process is performed using known techniques such as dithering and error diffusion.

[0044] In S140, CPU 210 executes print data output processing. The print data output processing is processing 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 before outputting it to printing mechanism 100. The control data includes data that specifies the transport amount of the sheet transport to be performed before partial printing. In the print data output processing, partial print data is output the same number of times as the number of partial prints to be performed. The print data output processing will be described in detail later.

[0045] By executing the printing process, the CPU 210 can cause the printing mechanism 100 to print the print image PI. Specifically, the CPU 210 controls the head drive unit 120, the main scanning unit 130, and the transport unit 140 to alternately perform partial printing and sheet transport multiple times, thereby performing printing. In one partial printing, with the paper M stopped on the paper tray 145, one main scan is performed while ejecting ink from the nozzles NZ of the print head 110 onto the paper M, thereby printing a portion of the print image on the paper M. In one sheet transport, the paper M is transported in the transport direction AR by a transport amount determined in the print data output process.

[0046] Figure 7 is a first explanatory diagram of printing in the first embodiment. Figure 7 shows an example of a print image PI printed on paper M. The print image PI includes multiple raster lines (for example, RL1 to RL3 in Figure 7) that each extend in the X direction (the main scanning direction during printing) in Figure 7 and are positioned at different positions in the Y direction (the transport direction AR during printing). Each raster line is a line on which multiple dots can be formed.

[0047] 7 also shows the head position, that is, the relative position of the print head 110 in the transport direction with respect to the paper M. Head positions P11 to P16, P21 to P23, P31, and P41 to P42 are the head positions for the last 12 partial prints out of multiple partial prints.

[0048] The hatched area of ​​the head position is the area where the nozzles NZ (also called the used nozzles) used for printing in the partial printing performed at that head position are located. The used nozzles are all or part of the usable nozzles.

[0049] In Figure 7, each raster line included in the print image PI is printed using three partial printings (so-called multi-pass printing). The three partial printings that print a specific raster line are also called a partial printing set. For example, each raster line in partial area NAc in Figure 7 is printed using a partial printing set executed at head positions P11, P12, and P13. Each raster line in partial area NAm is printed using a partial printing set executed at head positions P21, P22, and P23.

[0050] The reason for printing each raster line through multiple partial printings will be explained. Let us assume that each raster line is printed through only one partial printing. In this case, due to factors such as variations in the transport amount of the paper M, a defect known as banding may occur, in which white or black stripes appear at the boundary between an area printed through one partial printing and an area adjacent to that area in the transport direction AR and printed through another partial printing. Banding reduces the image quality of the print image PI. By printing each raster line through multiple partial printings, the defect known as banding described above can be suppressed. This is because, when dots on one raster line are formed through multiple partial printings, it is possible to suppress the same misalignment of all dots on one raster line relative to all dots on other raster lines.

[0051] FIG. 8 is an explanatory diagram of the recording rate of partial printing. The recording rates R11 to R14 in FIG. 8(A) are the dot recording rates in the partial printing executed at the head positions P11 to P14, respectively. The partial printing at each head position forms dots in three partial regions: a downstream region where dots are formed in the partial printing one time before and two times before, a central region where dots are formed in the partial printing one time before and one time after, and an upstream region where dots are formed in the partial printing one time after and two times after. For example, focusing on the partial printing at the head position P13, the partial region NAc which is the downstream region is a region where dots are also formed at the head positions P11 and P12, the partial region NAd which is the central region is a region where dots are also formed at the head positions P12 and P14, and the partial region NAe which is the upstream region is a region where dots are also formed at the head positions P14 and P15.

[0052] Focusing on the partial printing at the head position P13, in the partial region NAc which is the downstream region, the recording rate R13 linearly increases in the range of 0 < R13 < 50% as it goes toward the upstream side (the lower side in FIG. 8) in the conveyance direction AR. In the partial region NAd which is the central region, the recording rate R13 is a constant value (50%). In the partial region NAe which is the upstream region, the recording rate R13 linearly decreases in the range of 0 < R13 < 50% as it goes toward the upstream side (the lower side in FIG. 8) in the conveyance direction AR. In each partial region, the sum of the recording rates of the three partial printings that form dots in that partial region becomes 100% at all positions in the conveyance direction AR. For example, in the partial region NAc of FIG. 8(A), the sum of the recording rates R11, R12, and R13 is 100% at all positions in the conveyance direction AR. Thus, by changing the recording rate R13 according to the position in the conveyance direction AR in the upstream and downstream regions of each partial printing, it is possible to effectively suppress the conspicuousness of banding.

[0053] Figure 9 is a second explanatory diagram of printing in the first embodiment. As described above, Figure 7 illustrates the paper M and print image PI as fixed, and shows the position of the print head 110 (head position) that moves relative to the paper M and print image PI as the paper M is transported. In contrast, Figure 9 illustrates the print head 110 and presser member 146 as fixed, and shows the position of the paper M (hereinafter also referred to as the paper position) that moves relative to the print head 110 and presser member 146 as the paper M is transported. Figures 7 and 9 illustrate the same printing.

[0054] In Fig. 9, paper positions are indicated by strip-shaped rectangles. Paper positions M11 to M16, M21 to M23, M31, and M41 to M42 in Fig. 9 correspond to head positions P11 to P16, P21 to P23, P31, and P41 to P42 in Fig. 7. In other words, paper position Mk (k is a two-digit number) in Fig. 9 indicates the paper position when partial printing is performed at head position Pk in Fig. 7.

[0055] 7 and 9 further show sheet transports T12 to T16, T21 to T23, T31, and T41 to T42 with arrows. Sheet transport Tk (k is a two-digit number) is the sheet transport that takes place immediately before partial printing at head position Pk in Fig. 7. Furthermore, when sheet transport Tk is completed, paper M moves to paper position Mk.

[0056] In FIG. 9, images SIa and SIb currently being printed are shown as two hatched bands within the rectangle representing each paper position Mk. The first image SIa on the left is an image of the print image PI that has been printed in a partial printing prior to the partial printing performed at paper position Mk. The first image SIa is hatched with three levels of density. The raster lines in area SA1, which is hatched with the lightest density, have completed one of three partial printing runs for printing that raster line. The raster lines in area SA2, which is hatched with the medium density, have completed two of three partial printing runs for printing that raster line. The raster lines in area SA3, which is hatched with the darkest density, have completed all three partial printing runs for printing that raster line. The second image SIb on the right is an image of the print image PI that will be printed in the partial printing performed at paper position Mk.

[0057] In multi-pass printing, in which one partial area is printed in three partial prints as in this embodiment, the pass configuration must be set so that the following condition is met between any one partial print and the partial print one cycle after that one partial print (the partial print three cycles later in this embodiment): If this condition is not met, a gap will occur between the partial image printed in one partial print and the partial print one cycle later, making it impossible to print one continuous image.

[0058] Condition: If the raster line printed by the most upstream nozzle used in one partial printing is raster line A, and the raster line printed by the most downstream nozzle used in the partial printing one cycle later is raster line B, then raster line B is adjacent to the upstream side of raster line A.

[0059] To satisfy this condition, the maximum value of the total transport amount of the sheet transport for one cycle executed from printing one partial to printing the partial one cycle later is the nozzle length D. The total transport amount reaches the maximum value when the most upstream nozzle used in printing one partial is the most upstream nozzle NZu (FIG. 4) of the print head 110, and the most downstream nozzle used in printing the partial one cycle later is the most downstream nozzle NZd (FIG. 4) of the print head 110.

[0060] For example, let's look at the partial printing performed at head position P11. Figure 7 shows raster line RLa printed by the most upstream nozzle NZa used in the partial printing performed at head position P11, and raster line RLb printed by the most downstream nozzle NZb used in the partial printing performed one cycle later at head position P14. Raster line RLb is adjacent to the upstream side of raster line RLa. This relationship is satisfied in all partial printings except for the final three partial printings, in which there is no partial printing performed one cycle later.

[0061] Here, when printing one partial area with three partial prints as in this embodiment, ignoring the need to prevent the upstream edge of the paper M from being positioned in the prohibited range NGA, the most efficient path configuration is one in which the transport amount for each sheet transport is 1 / 3 (D / 3) of the nozzle length D and printing is performed using all nozzles NZ for the nozzle length D (so-called equal feed). For this reason, as shown in Figures 7 and 9, when printing an area away from the upstream edge of the paper M, printing is performed using equal feed. For example, the transport amount for sheet transports T12 to T16 in Figures 7 and 9 is (D / 3).

[0062] In contrast, when printing near the upstream edge of the paper M (the lower edge in Figure 9), in order to prevent partial printing when the upstream edge of the paper M is located in the prohibited range NGA as described above, the upstream edge of the paper M is configured to jump over the prohibited range NGA in one sheet transport.

[0063] The above-mentioned prohibited range NGA is illustrated in Fig. 9. For example, in the example of Fig. 9, sheet transport T31 is executed so that the upstream edge of the sheet M moves from a position upstream of the prohibited range NGA to a position downstream of the prohibited range NGA.

[0064] When the paper M is unwound from the roll R, the paper M bends, and as described above, the paper M is more likely to become soiled due to contact with the print head 110, so the length of the prohibited range NGA in the conveying direction AR becomes longer. For example, in this embodiment, the length of the prohibited range NGA in the conveying direction AR is longer than (D / 3). For this reason, in this embodiment, when printing near the upstream end of the paper M (the lower end in FIG. 9), a configuration other than uniform feed is adopted to make the conveyance amount of sheet conveyance T31 longer than (D / 3).

[0065] Specifically, as described above, the total transport distance for one cycle must be less than the nozzle length D. Therefore, to maximize the transport distance of sheet transport T31, the transport distances of the two sheet transports T22 and T23 before sheet transport T31 and the two sheet transports T41 and T42 after sheet transport T31 are set to less than (D / 3). If sheet transports T22 and T23 are set too short, the length in the transport direction AR of the partial area printed in the subsequent partial printing (e.g., partial area NAm in FIG. 7) becomes too short. In this case, smooth changes in recording rate, such as those shown in FIG. 8, cannot be achieved, which can result in image quality problems such as noticeable banding. Furthermore, if sheet transports T22 and T23 are set too short, transport accuracy may deteriorate, potentially resulting in degradation of image quality. For this reason, the transport distances of sheet transports T22 and T23 are set to the minimum value within a range that does not result in such image quality problems. The transport amount of sheet transports T41 and T42 is determined to be the same as the transport amount of sheet transports T22 and T23. The transport amount of sheet transports T22, T23, T41, and T42 is set to a small transport amount TVs. As a result, the transport amount of sheet transport T31 can be increased up to (D-2 x TVs), so the transport amount of sheet transport T31 is set to the maximum settable value (D-2 x TVs).

[0066] Here, the conveyance amount of the sheet conveyance T31 is defined as the large conveyance amount TVb, the conveyance amount (D / 3) of the uniform feed is defined as the medium conveyance amount TVm, and the length of the conveyance direction AR of the prohibited range NGA is defined as the prohibited range length NGL. The large conveyance amount TVb is larger than the medium conveyance amount TVm, and the small conveyance amount TVs is smaller than the medium conveyance amount TVm (TVs < TVm < TVb). And the large conveyance amount TVb is larger than the prohibited range length NGL, and the medium conveyance amount TVm is smaller than the prohibited range length NGL (TVm < NGL < TVb).

[0067] In order for the upstream end of the sheet M to cross the prohibited range NGA by the sheet conveyance T31 at the large conveyance amount TVb, at the paper position at the start point of the sheet conveyance T31 (in the example of FIG. 9, the paper position M23), the upstream end of the sheet M needs to be located within the allowable range AA adjacent to the upstream side of the prohibited range NGA. The length of the conveyance direction AR of the allowable range AA (referred to as the allowable range length AL) is the difference between the large conveyance amount TVb and the prohibited range length NGL (TVb - NGL). When the upstream end of the sheet M at the start point of the sheet conveyance T31 is located on the upstream side of the allowable range AA, after the completion of the sheet conveyance T31, the upstream end of the sheet M is located within the prohibited range NGA. Also, when the upstream end of the sheet M at the start point of the sheet conveyance T31 is located on the downstream side of the allowable range AA, at the start point of the sheet conveyance T31, the upstream end of the sheet M is located within the prohibited range NGA.

[0068] Here, at the paper position M16 after the last sheet conveyance T16 (FIG. 9) at the medium conveyance amount TVm, the position of the upstream end of the sheet M varies due to the blank space on the downstream side of the printed image PI, the length of the conveyance direction AR of the sheet M, etc. Also, when there is a blank part in the middle of the conveyance direction AR of the printed image PI and printing is performed by skipping the blank, depending on the blank part included in the printed image PI, the position of the upstream end of the sheet M at the paper position M16 varies. For this reason, in this embodiment, the number of times of sheet conveyance at the small conveyance amount TVs executed before the sheet conveyance T31 is adjusted so that the upstream end of the sheet M is located within the allowable range AA at the start point of the sheet conveyance T31. In the example of FIG. 9, the three sheet conveyances T21 to T23 executed before the sheet conveyance T31 are executed at the small conveyance amount TVs.

[0069] FIG. 10 is a third explanatory diagram of printing in the first embodiment. Similar to FIG. 7, FIG. 10 illustrates the relative position of the print head 110 with respect to the paper M. FIG. 11 is a fourth explanatory diagram of printing in the first embodiment. Similar to FIG. 9, FIG. 11 illustrates the relative position of the paper with respect to the print head 110 and the presser member 146. FIGS. 10 and 11 illustrate the same print, but different print from those in FIGS. 7 and 9. In the examples of FIGS. 7 and 9, at paper position M16 after sheet transport T16, the upstream edge of paper M is a distance d1 upstream from the allowable range AA. In contrast, in the examples of FIGS. 10 and 11, at paper position M16 after sheet transport T16, the upstream edge of paper M is a distance d2 upstream from the allowable range AA. Distance d2 is greater than distance d1. For this reason, in the examples of Figures 10 and 11, in addition to the path configurations of Figures 7 and 9, sheet transport T24, which is executed at the small transport amount TVs, and partial printing, which is executed at head position P24 after sheet transport T24, are added. That is, in the examples of Figures 10 and 11, four sheet transports T21 to T24, which are executed before sheet transport T31, are executed at the small transport amount TVs. As a result, in the examples of Figures 10 and 11, the upstream edge of sheet M is located within the allowable range AA at the sheet position at the start of sheet transport T31 at the large transport amount TVb (sheet position M24 in Figure 11). As a result, in the examples of Figures 10 and 11, as in the examples of Figures 7 and 9, sheet transport T31 causes the upstream edge of sheet M to jump over the prohibited range NGA.

[0070] FIG. 12 is an explanatory diagram of printing in a comparative example. Similar to FIG. 11, FIG. 12 illustrates the relative position of the paper with respect to the print head 110 and the presser member 146. In this comparative example, similar to the examples in FIGS. 10 and 11, at paper position M16 after sheet transport T16, the upstream edge of the paper M is a distance d2 upstream from the allowable range AA. However, unlike the examples in FIGS. 10 and 11, the comparative example does not include additional sheet transports performed at small transport amounts TVs. That is, in the comparative example, sheet transports T21 to T23 at small transport amounts TVs performed before sheet transport T31 are performed three times, similar to the examples in FIGS. 7 and 9. Therefore, in the comparative example, at the paper position at the start of sheet transport T31 at large transport amount TVb (paper position M23 in FIG. 12), the upstream edge of the paper M is located upstream of the allowable range AA. As a result, the upstream edge of the sheet M cannot jump over the prohibited range NGA by the sheet transport T31, and at the sheet position M31 after the sheet transport T31, the upstream edge of the sheet M is located within the prohibited range NGA. For this reason, in the comparative example (FIG. 12), the sheet M is more likely to become soiled than in the present embodiment (FIGS. 10 and 11).

[0071] FIG. 13 is a fifth explanatory diagram of printing in the first embodiment. Similar to FIG. 7, FIG. 13 illustrates the relative position of the print head 110 with respect to the paper M. FIG. 14 is a sixth explanatory diagram of printing in the first embodiment. Similar to FIG. 9, FIG. 14 illustrates the relative position of the paper with respect to the print head 110 and the presser member 146. FIGS. 13 and 14 illustrate the same print, but different prints from FIGS. 7 and 9, and FIGS. 10 and 11. In the examples of FIGS. 13 and 14, at paper position M16 after sheet transport T16, the upstream edge of paper M is a distance d3 upstream from the allowable range AA. Distance d3 is greater than distance d1 (FIG. 9) and distance d2 (FIG. 11). For this reason, in the examples of Figures 13 and 14, in addition to the path configurations of Figures 7 and 9, sheet transport T24 is performed at the small transport amount TVs, partial printing is performed at head position P24 after sheet transport T24, and sheet transport T25 is performed at the small transport amount TVs, partial printing is performed at head position P25 after sheet transport T25. That is, in the examples of Figures 13 and 14, five sheet transports T21 to T25 performed before sheet transport T31 are performed at the small transport amount TVs. As a result, in the examples of Figures 13 and 14, the upstream edge of sheet M is located within the allowable range AA at the sheet position at the start of sheet transport T31 at the large transport amount TVb (sheet position M24 in Figure 14). As a result, in the examples of Figures 13 and 14, as in the examples of Figures 7, 9, 10, and 11, sheet transport T31 causes the upstream edge of sheet M to jump over the prohibited range NGA. If sheet transports T24 and T25 at the small transport distance TVs are not added, the upstream edge of the sheet M cannot jump over the prohibited range NGA by sheet transport T31, as in the comparative example of FIG.

[0072] A-2. Print data output process Next, we will explain the print data output process for the normal printing mode at S140 in Fig. 6. As described above, the print data output process uses the print data generated at S130 to generate partial print data for each partial print, and adds various control data to the partial print data before outputting it to the printing mechanism 100. Fig. 15 is a flowchart of the print data output process.

[0073] The print data generated in S130 of Fig. 6 represents the print image PI (Fig. 7) to be printed. Therefore, the print data includes multiple pieces of raster data corresponding to the multiple raster lines included in the print image PI.

[0074] 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, sequentially from the downstream side of the transport direction AR during printing (the +Y side in FIG. 7).

[0075] Here, the three partial printings for printing a target raster line are also referred to as a target partial printing set. For example, if the raster line RL2 in FIG. 7 is the target raster line, the target partial printing set is three partial printings performed at head positions P11, P12, and P13. The three nozzles NZ used to form dots on the target raster line in the target partial printing set are also referred to as a target nozzle set. For example, if the raster line RL2 in FIG. 7 is the target raster line, the target nozzle set is three nozzles consisting of a nozzle NZ that forms dots on the raster line RL2 at head position P11, a nozzle NZ that forms dots on the raster line RL2 at head position P12, and a nozzle NZ that forms dots on the raster line RL2 at head position P13.

[0076] In S210, the CPU 210 divides the target raster data into three parts and allocates them to the three nozzles NZ that make up the target nozzle set.

[0077] Specifically, the CPU 210 acquires the divided pattern data PD corresponding to the target raster line. An example of the divided pattern data PD is shown in FIG. 8B. As shown in FIG. 8B, the divided pattern data PD is data having a value corresponding to each pixel of the target raster line. The value corresponding to each pixel is, for example, one of "0," "1," or "2." The value "0" indicates that the dot corresponding to that pixel should be formed in the first partial print of the target portion print set. The value "1" indicates that the dot corresponding to that pixel should be formed in the second partial print of the target portion print set. The value "2" indicates that the dot corresponding to that pixel should be formed in the third partial print of the target portion print set. The divided pattern data PD is created so as to achieve the recording rate shown in FIG. 8A described above, depending on the position of the target raster line in the transport direction AR. The CPU 210 divides the target raster data into data for three partial prints that constitute the target portion print set in accordance with the divided pattern data PD. The CPU 210 assigns each of the three divided data to the three nozzles NZ that constitute the target nozzle set. For example, a memory area is reserved in the buffer area 231 of the volatile memory device 230 for storing print data for a set of nozzles of interest (for three partial prints), and the data assigned to the three nozzles NZ is stored in addresses in the memory area corresponding to the three nozzles NZ, respectively.

[0078] In S220, the CPU 210 determines whether all raster data has been processed. If the raster data of interest is the most upstream raster line of the print image PI, such as raster line RL3 in the example of Figure 7, it is determined that all raster lines have been processed. If the raster data of interest is not the most upstream raster line of the print image PI, it is determined that there are unprocessed raster lines.

[0079] If all raster lines have been processed (S220: YES), the CPU 210 proceeds to S230, and if there are any unprocessed raster lines (S220: NO), the CPU 210 proceeds to S235.

[0080] In S230, the CPU 210 outputs the partial print data for the target partial print set and the carry amount data to the printing mechanism 100, and ends the print data output process. That is, the partial print data for the final three partial prints and the carry amount data indicating the carry amount for the sheet transport to be performed immediately before each of these three partial prints are output to the printing mechanism 100. In the example of Fig. 7, the partial print data for the three partial prints performed at head positions P31, P41, and P42 and the carry amount data indicating the carry amount for each of sheet transports T31, T41, and T42 are output.

[0081] When the printing mechanism 100 receives the partial print data for three partial prints and the transport amount data for three sheet transports, it executes three sheet transports and the final three partial prints executed after each of the three sheet transports in accordance with these data, thereby completing the printing.

[0082] In S235, the CPU 210 updates the nozzle set of interest. Specifically, the numbers indicating the three nozzles NZ that make up the nozzle set of interest are changed to numbers indicating the nozzle that is one nozzle upstream of the current nozzle.

[0083] In S240, CPU 210 determines whether raster data has been assigned to all active nozzles for the first target portion printing. The first target portion printing is the first partial printing in the target portion printing set. Specifically, if the number indicating the nozzle for the first target portion printing in the updated target nozzle set 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 are active nozzles to which raster data has not been assigned (S240: NO), the process returns to S200.

[0084] If raster data has been assigned to all of the operating nozzles (S240: YES), in S245 the CPU 210 outputs the partial print data for printing the first target portion and the carry amount data to the printing mechanism 100. The partial print data is a group of raster data assigned to the operating nozzles for printing the first target portion. The carry amount data is control data indicating the carry amount, and indicates the carry amount of the sheet transport that should be performed immediately before printing the first target portion. Before S260, which will be described later, is performed, the carry amount is the medium carry amount TVm, which is the carry amount for uniform feed. After S260, which will be described later, is performed, the carry amount is the carry amount determined in S260 (either the medium carry amount TVm, the small carry amount TVs, or the large carry amount TVb).

[0085] When the printing mechanism 100 receives the partial print data and the carry amount data, it carries out sheet transport by the carry amount indicated by the carry amount data, and then carries out the first partial printing using the partial print data.

[0086] In S250, the CPU 210 calculates the excess amount VO from the reference position for printing the leading target portion. The excess amount VO indicates the length from the reference position RP to the most upstream nozzle NZ for printing the leading target portion when the most upstream nozzle NZ is located upstream of the reference position RP. The reference position RP (FIG. 7) is a position in the transport direction AR determined on the paper M. The reference position RP is determined at a predetermined distance from the upstream edge of the paper M. Because the upstream edge of the paper M is the edge cut by the sheet cutting unit 150 under the control of the CPU 210, the CPU 210 recognizes the positional relationship between the upstream edge of the paper M and the nozzles NZ of the print head 110. Therefore, the CPU 210 can also recognize the positional relationship between the reference position RP and the nozzles NZ of the print head 110, and can therefore calculate the excess amount VO.

[0087] In the example of Fig. 7, when the partial printing performed at head position P13 is the target leading partial printing, the upstream-most nozzle NZ of the partial printing performed at head position P13 is located upstream of the pressing reference position RP, so the excess amount VO shown in Fig. 7 is calculated. The unit of the excess amount VO is expressed, for example, as the number of raster lines.

[0088] When the most upstream nozzle NZ is located at the same position as the reference position RP or downstream of the reference position RP, the excess amount VO is 0. In the example of Fig. 7, when the partial printing performed at head positions P11 and P12 is the first target partial printing, the most upstream nozzle NZ of these partial printings is located downstream of the reference position RP, so the excess amount VO is 0.

[0089] In S255, the CPU 210 determines whether the excess amount VO calculated in S250 has exceeded 0 for the first time. In the example of Fig. 7, when the partial printing performed at head position P13 is the target leading partial printing, it is determined that the excess amount VO has exceeded 0 for the first time.

[0090] If it is determined that the excess amount VO has exceeded 0 for the first time (S255: YES), in S260, the CPU 210 determines a path configuration after the current target portion printing set based on the excess amount VO. The fact that the excess amount VO has exceeded 0 for the first time means that printing has progressed to near the upstream edge of the paper M. In order to achieve the path configurations shown in FIGS. 7, 9, etc., when printing has progressed to near the upstream edge of the paper M, it is necessary to transition the path configuration from a configuration that performs uniform feeding at the medium conveyance amount TVm to a configuration (FIGS. 7, 9, etc.) that includes sheet transport at the large conveyance amount TVb or the small conveyance amount TVs. For this reason, if it is determined that the excess amount VO has exceeded 0 for the first time, the path configuration after the current target portion printing set is determined to be a configuration that includes sheet transport at the large conveyance amount TVb or the small conveyance amount TVs.

[0091] As shown in FIG. 7, the target partial printing set at the time when the excess amount VO exceeds 0 for the first time is three partial printings performed at head positions P13, P14, and P15. For this reason, the pass configuration (the transport amount and the range of nozzles used for each sheet transport) after the partial printing at head position P15 is determined. Specifically, the sheet transports after the partial printing at head position P15 are determined to be one sheet transport T16 at a medium transport amount TVm, three to five sheet transports at a small transport amount TVs (three sheet transports T21 to T23 in the example of FIG. 7), one sheet transport T31 at a large transport amount TVb, and two sheet transports T41 and T42 at small transport amounts TVs. Then, depending on the determined sheet transports, the range of nozzles used in the partial printing after each sheet transport (for example, the hatched range in FIG. 7) is determined.

[0092] Here, the excess amount VO varies depending on the paper position relative to the print head 110. Specifically, the excess amount VO varies within a range greater than or equal to 0 and less than the medium conveyance amount TVm(D / 3). The smaller the excess amount VO, the greater the distance between the print head 110 and the upstream edge of the paper M. For this reason, the smaller the excess amount VO, the greater the distance (distance d1 in FIG. 9, distance d2 in FIG. 11, distance d3 in FIG. 14) between the upstream edge of the paper M at paper position M16 after sheet conveyance T16 and the permissible range AA. For example, in the examples of FIGS. 7 and 9, the excess amount VO is large and is a value close to the medium conveyance amount TVm. In the examples of FIGS. 10 and 11, the excess amount VO is smaller than in the examples of FIGS. 7 and 9, and is approximately half of the medium conveyance amount TVm. In the examples of FIGS. 13 and 14, the excess amount VO is smaller than in the examples of FIGS. 10 and 11, and is a value close to 0. For this reason, as described above, the distance d2 in the examples of Figures 10 and 11 is greater than the distance d1 in the examples of Figures 7 and 9, and the distance d3 in the examples of Figures 13 and 14 is greater than the distance d2 in the examples of Figures 10 and 11 (d3>d2>d1).

[0093] In this embodiment, the smaller the excess amount VO, the more the number of times the sheet is conveyed by the small conveyance amount TVs before the sheet conveyance T31 by the large conveyance amount TVb is increased. Specifically, in this embodiment, the number of times the sheet is conveyed by the small conveyance amount TVs before the sheet conveyance T31 is set to three times as the reference number. The additional number Nad is determined by the following formula (1). Nad=rounddown[(TVm-VO) / TVs] …(1) In formula (1), rounddown[A] means an integer obtained by rounding down the decimal point of the number A.

[0094] 7 and 9, the number of sheet transports by the small transport amount TVs performed before sheet transport T31 is determined to be three (sheet transports T21 to T23). In the example of FIGS. 10 and 11, the number of sheet transports by the small transport amount TVs performed before sheet transport T31 is determined to be four (sheet transports T21 to T24). In the example of FIGS. 13 and 14, the number of sheet transports by the small transport amount TVs performed before sheet transport T31 is determined to be five (sheet transports T21 to T25). As a result of determining the path configuration in this way, the number of sheet transports by the small transport amount TVs is adjusted so that the upstream edge of the sheet M is located within the allowable range AA at the sheet position at the start of sheet transport T31.

[0095] If it is determined that the excess amount VO does not exceed 0 (S255: NO), or if the excess amount VO already exceeded 0 when the partial printing before the current leading target partial printing was the leading target partial printing (S255: NO), the CPU 210 skips S260 and proceeds to S265.

[0096] In S265, the CPU 210 updates the target portion printing set. That is, of the three partial printings that make up the current target portion printing set, the second partial printing is set as the first partial printing of the new target portion printing set (the first target portion printing described above). Of the three partial printings that make up the current target portion printing set, the third partial printing is set as the second partial printing of the new target portion printing set. The partial printing to be performed next after the three partial printings that make up the current target portion printing set is set as the third partial printing of the new target portion printing set. For example, if the current target portion printing set is three partial printings performed at head positions P11, P12, and P13 in FIG. 7, the new target portion printing set is three partial printings performed at head positions P12, P13, and P14.

[0097] In S270, the CPU 210 updates the target nozzle set. That is, the three nozzles that make up the target nozzle set are set as nozzles corresponding to the new target partial printing set. The third partial printing nozzle added to the new target partial printing set is set as the initial nozzle at this point. Before S260 is executed, the initial value is the most downstream nozzle NZd, and after S260 is executed, the initial value is a value corresponding to the pass configuration determined in S260. After S270, the CPU 210 returns the process to S200.

[0098] According to the first embodiment described above, the printer 200 includes a housing 1, a print head 110 provided within the housing 1, and a roll mounting unit 11 to which a roll R is detachably mounted (FIG. 2). The roll R is formed by a roll of paper M, a sheet-like printing medium, wound around it (FIG. 2). The printer 200 further includes a transport unit 140 (FIG. 2) that transports the paper M in the transport direction along a transport path including an upstream path TR from the roll mounting unit 11 to the print head 110, and a cutter 151 that cuts the paper M at a specific position Cp on the upstream path TR (FIG. 2). The transport unit 140 includes a holder (in this embodiment, a high support member HP and a presser member 146) located between the cutter 151 and the print head 110 (FIGS. 3 and 5). The holder holds the paper M in a wavy state that is deformed in a direction perpendicular to the transport direction (FIG. 5B).

[0099] With this configuration, the cutter 151 cuts the paper M at a specific position on the upstream path from the roll mounting unit 11 to the print head 110, so the distance from the roll mounting unit 11 to the cutting position is relatively short. This reduces the amount of paper M that needs to be rewound. To explain this in more detail, for example, when removing the roll R from the housing 1 along with the paper feed tray 5, the leading edge of the paper M that has been unwound from the roll R and cut by the cutter 151 may bend if it comes into contact with the housing 1 or the like. To prevent this, the unwound portion of the paper M is rewound before removal. In this embodiment, the amount of paper R that needs to be rewound is reduced, thereby reducing the time required for rewinding. This ultimately reduces the user's waiting time (the time spent waiting without removing the paper until rewinding is complete).

[0100] Furthermore, in the above embodiment, the CPU 210 causes the printing mechanism 100 to execute sheet transport (for example, T12 to T16 in FIG. 7) to transport the paper M at the medium transport amount TVm and partial printing after the sheet transport (for example, P12 to P16 in FIG. 7) multiple times. Subsequently, the CPU 110 causes the printing mechanism 100 to execute sheet transport (for example, T21 to T23 in FIG. 7) to transport the paper M at a small transport amount TVs smaller than the medium transport amount TVm and partial printing after the sheet transport (for example, P21 to P23 in FIG. 7), and causes the printing mechanism 100 to execute sheet transport (for example, T31 in FIG. 7) to transport the paper M at a large transport amount TVb larger than the medium transport amount TVm and partial printing after the sheet transport (for example, P31 in FIG. 7) (FIG. 7, etc.). In sheet transport (e.g., T31 in FIG. 7) for transporting sheet M at large transport amount TVb, sheet M is transported from a start position (e.g., sheet position M23 in FIG. 9) where the upstream edge of sheet M is held by pressure member 146 to an end position (e.g., sheet position M31 in FIG. 9) where the upstream edge of sheet M is not held by pressure member 146 (e.g., FIG. 9, etc.). CPU 210 transports sheet M at small transport amount TVs so that the upstream edge of sheet M is positioned within tolerance range AA at the start position of sheet transport (e.g., T31) for transporting sheet M at large transport amount TVb. The number of sheet transports T21 to T23 that transport paper M by the small transport amount TVs is adjusted (for example, in FIGS. 7, 9 to 11, 13, and 14). In the example of FIGS. 7 and 9, the number of sheet transports T21 to T23 that transport paper M by the small transport amount TVs is three, in the example of FIGS. 10 and 11, the number of sheet transports T21 to T24 that transport paper M by the small transport amount TVs is four, and in the example of FIGS. 13 and 14, the number of sheet transports T21 to T25 that transport paper M by the small transport amount TVs is five. The allowable range AA is a range in the transport direction AR that is determined for the presser member 146.

[0101] If the paper M is cut after being unwound from the roll R, the vicinity of the upstream edge of the paper M is likely to deform during printing, which can lead to problems such as the paper M coming into contact with the print head 110 (e.g., paper M becoming dirty). This problem is particularly likely to occur before and after sheet transport T31, which transports the paper M from the start position where the upstream edge of the paper M is held by the presser member 146 to the end position where the upstream edge is no longer held. If the large transport amount TVb of the sheet transport T31 is made sufficiently large, the prohibited range NGA can be exceeded, and this problem can be avoided. However, in multi-pass printing, there is a limit to how large the large transport amount TVb can be increased because printing must be completed as described above. According to this embodiment, the number of times sheet conveyance is performed at the small conveyance amount TVs is adjusted so that the upstream edge of the paper M is positioned within the allowable range AA at the start position of sheet conveyance T31 (for example, M23 in FIG. 9, M24 in FIG. 11, and M25 in FIG. 14). This allows the position of the paper M before and after sheet conveyance T31 to be set to an appropriate position that jumps over the prohibited range NGA (FIGS. 9, 11, and 14). Therefore, it is possible to prevent the paper M from coming into contact with the print head 110 without excessively increasing the large conveyance amount TVb. In other words, it is possible to prevent the paper M from coming into contact with the print head 110 while still achieving multi-pass printing.

[0102] More specifically, when the upstream edge of the sheet M is at a first position (specifically, a position that is a distance d1 away from the allowable range AA (FIG. 9)) at the completion of sheet transport T16, the CPU 210 executes sheet transports T21-T23 at the small transport amount TVs N times (N is an integer greater than or equal to 1, three times in the example of FIG. 9). Then, when the upstream edge of the sheet M is at a second position that is upstream of the first position (specifically, a position that is a distance d2 away from the allowable range AA (FIG. 11)) at the completion of sheet transport T16, the CPU 210 executes sheet transports T21-T24 at the small transport amount TVs M times (M is an integer that satisfies M>N, four times in the example of FIG. 11). As a result, by increasing the number of sheet transports at the small transport amount TVs the further upstream the upstream edge of the sheet M is at the completion of sheet transport T16, the position of the sheet M before and after sheet transport T31 can be set to an appropriate position that jumps over the prohibited range NGA.

[0103] Furthermore, according to the above embodiment, the transport amounts of the three sheet transports T21 to T23 in the printing of Figure 9, the four sheet transports T21 to T24 in the printing of Figure 11, and the five sheet transports T21 to T25 in the printing of Figure 14 are all the same transport amount (specifically, the small transport amount TVs).

[0104] According to the above embodiment, when four sheet transports T21 to T24 are performed as in the example of Fig. 11, it is only necessary to add one sheet transport of the same transport amount, which makes control easier compared to when three sheet transports T21 to T23 are performed as in the example of Fig. 9. Similarly, when five sheet transports T21 to T25 are performed as in the example of Fig. 14, it is only necessary to add two sheet transports of the same transport amount, which makes control easier compared to when three sheet transports T21 to T23 are performed as in the example of Fig. 9.

[0105] Furthermore, according to the above embodiment, in the printing of FIG. 10, one sheet transport T24 is added after the three sheet transports T21 to T23 in the printing of FIG. 7. In FIG. 10, the range NR2 (hatched portion) of nozzles used at head position P24, which is added after sheet transport T24, is the same as the range NR1 (hatched portion) of nozzles used at the immediately preceding head position P23. That is, the multiple nozzles used in the partial printing performed after the added sheet transport T24 (partial printing at head position P24 in FIG. 10) are the same as the multiple nozzles used in the partial printing performed after sheet transport T23, which is the final transport operation of the three sheet transports T21 to T23 (partial printing at head position P23 in FIGS. 9 and 10). As a result, the control of the partial printing at head position P24, which is added in conjunction with the addition of sheet transport T24, can be achieved by simply repeating the control (e.g., routine control) of the partial printing at the immediately preceding head position P23. Therefore, the addition of sheet transport T24 and partial printing after sheet transport T24 can be easily realized.

[0106] Similarly, in the printing of Fig. 13, two sheet transports T24 and T25 are added after the three sheet transports T21 to T23 in the printing of Fig. 7. In Fig. 13, the ranges NR2 and NR3 (hatched portions) of nozzle usage at head positions P24 and P25, which are added after sheet transports T24 and T25, respectively, are the same as the range NR1 (hatched portion) of nozzle usage at head position P23, which is the previous one. In other words, the multiple nozzles used in the partial printing performed after the two added sheet transports T24 and T25 (partial printing at head positions P24 and P25 in Fig. 13) are the same as the multiple nozzles used in the partial printing performed after sheet transport T23, which is the final transport operation of the three sheet transports T21 to T23 (partial printing at head position P23 in Figs. 9 and 13). As a result, the control of partial printing at head positions P24 and P25, which are added in conjunction with the addition of sheet conveyances T24 and T25, can be achieved simply by repeating the control of partial printing at the previous head position P23. Therefore, the addition of sheet conveyances T24 and 25 and partial printing after sheet conveyances T24 and T25 can be easily realized.

[0107] Furthermore, according to the above embodiment, in the print data output process, the CPU 210 calculates the excess amount VO relative to the reference position RP set on the paper M (S250 in FIG. 15), and when the excess amount VO exceeds 0 for the first time (YES in S255 in FIG. 15), the CPU 210 determines the subsequent pass configuration in accordance with the excess amount VO (S260 in FIG. 15). In this way, by introducing the excess amount VO, the pass configuration for printing near the upstream edge of the paper M can be determined at an appropriate timing before the process for printing near the upstream edge of the paper M is started. As a result, partial print data can be generated efficiently, for example, so that the process of recreating partial print data in accordance with the pass configuration does not occur.

[0108] As can be seen from the above explanation, in this embodiment, sheet transports T12 to T16 at a medium transport amount TVm are each an example of a first transport operation, sheet transports T21 to T25 at a small transport amount TVs are each an example of a second transport operation, and sheet transport T31 at a large transport amount TVb is an example of a third transport operation.

[0109] B. Second Example Figure 16 is a first explanatory diagram of printing in the second embodiment. Similar to Figure 7, Figure 16 illustrates the relative position of the print head 110 with respect to the paper M. Figure 17 is a second explanatory diagram of printing in the second embodiment. Similar to Figure 9, Figure 17 illustrates the relative position of the paper with respect to the print head 110 and the presser member 146. Figures 16 and 17 are of the same print.

[0110] Figure 18 is a third explanatory diagram of printing in the second embodiment. Like Figure 7, Figure 18 illustrates the relative position of the print head 110 with respect to the paper M. Figure 19 is a fourth explanatory diagram of printing in the second embodiment. Like Figure 9, Figure 19 illustrates the relative position of the paper with respect to the print head 110 and the presser member 146. Figures 18 and 19 illustrate the same printing, but different printing from Figures 16 and 17.

[0111] In the examples of FIGS. 16 and 17, at paper position M16 after sheet transport T16, the upstream edge of paper M is a distance da away from the allowable range AA on the upstream side. In contrast, in the examples of FIGS. 18 and 19, at paper position M16 after sheet transport T16, the upstream edge of paper M is a distance db away from the allowable range AA on the upstream side. Distance db is smaller than distance da. As explained in the first embodiment, the smaller the excess amount VO, the greater the distance between the upstream edge of paper M at paper position M16 after sheet transport T16 and the allowable range AA (distance da in FIG. 16, distance db in FIG. 19). As can be seen from this, the prints in FIGS. 16 and 17 are examples where the excess amount VO is relatively small, and the prints in FIGS. 18 and 19 are examples where the excess amount VO is greater than in the prints in FIGS. 16 and 17.

[0112] In the second embodiment, the path configuration after partial printing at paper position M16 (partial printing at head position P16) is different from that in the first embodiment. That is, in the second embodiment, the path configuration determined in S260 of Fig. 15, in other words, the path configuration for printing near the upstream edge of paper M, is different from that in the first embodiment.

[0113] In the first embodiment, the number of sheet transports at the small transport amount TVs and the number of partial prints are adjusted according to the excess amount VO (in other words, according to the distances d1, d2, and d3 in FIGS. 9, 11, and 14). In contrast, in the second embodiment, the number of sheet transports at the medium transport amount and the number of partial prints are fixed, regardless of the excess amount VO. That is, in the second embodiment, regardless of the excess amount VO, after partial printing at head position P16, three sheet transports at small transport amounts T21B, T22, and T23 are performed, followed by one sheet transport T31 at the large transport amount TVb, and then two sheet transports at small transport amounts T41 and T42.

[0114] In the second embodiment, among the three sheet transports T21B, T22, and T23 with a small transport amount, the transport amount of the first sheet transport T21B is variable, and the transport amounts of the remaining two sheet transports T22 and T23 are fixed. The transport amounts of the last two sheet transports T41 and T42 with a small transport amount are also fixed. The fixed transport amounts of the sheet transports T22, T23, 41, and T42 are the same as the small transport amount TVs in the first embodiment. The sheet transport T21B is also called the variable sheet transport T21B, and the transport amount of the sheet transport T21B is also called the variable transport amount TVv.

[0115] The variable transport amount TVv varies according to the excess amount VO (in other words, according to the distances da and db in FIGS. 17 and 19) within the range of not less than the fixed small transport amount TVs and less than the medium transport amount TVm (TVs ≦ TVv < TVm). Specifically, the smaller the excess amount VO, the larger the variable transport amount TVv. Therefore, the larger the distance (for example, the distance da in FIG. 17 and the distance db in FIG. 19) between the upstream end of the sheet M and the allowable range AA at the sheet position M16 after the sheet transport T16, the larger it is.

[0116] More specifically, the CPU 210 variably changes the variable conveyance amount TVv stepwise according to the excess amount VO. In this embodiment, the variable conveyance amount TVv is set to a multiple of the small conveyance amount TVs. For example, assume that the medium conveyance amount TVm, which is the upper limit value of the variable conveyance amount TVv, is more than 3 times and less than 4 times the small conveyance amount TVs. In this case, when 0 < VO < TVs, the variable conveyance amount TVv is set to 3TVs. When TVs ≤ VO < 2TVs, the variable conveyance amount TVv is set to 2TVs. When 2TVs ≤ VO, the variable conveyance amount TVv is set to TVs. For example, in the examples of FIGS. 16 and 17, the variable conveyance amount TVv of the variable sheet conveyance T21B is set to 3 times (3TVs) the small conveyance amount TVs. In the examples of FIGS. 18 and 19, the variable conveyance amount TVv of the variable sheet conveyance T21B is set to the small conveyance amount TVs. Note that, to avoid complication in the drawings, in this embodiment, it is assumed that the medium conveyance amount TVm is more than 3 times and less than 4 times the small conveyance amount TVs, and the variable conveyance amount TVv is changed in three steps. However, actually, since the medium conveyance amount TVm is even larger than 4 times the small conveyance amount TVs, the variable conveyance amount TVv is changed in more steps.

[0117] FIG. 20 is an explanatory diagram of the recording rate of partial printing in the second embodiment. The recording rates R16, R21 to R23 in FIG. 20 are the dot recording rates in the partial printing executed at the head positions P16, P21 to P24, respectively. FIG. 20(A) shows the recording rate in the examples of FIGS. 16 and 17, that is, the recording rate when the excess amount VO is small and the variable conveyance amount TVv of the sheet conveyance T21B is large. FIG. 20(B) shows the recording rate in the examples of FIGS. 18 and 19, that is, the recording rate when the excess amount VO is large and the variable conveyance amount TVv of the sheet conveyance T21B is small.

[0118] The larger the variable carry amount TVv, the larger the range of nozzles NRa, NRb, and NRc (hatched area) used in the three partial printing operations at head positions P21, P22, and P23. Accordingly, the larger the variable carry amount TVv, the longer the length in the transport direction AR of the partial area NAx printed in the three partial printing operations at head positions P21, P22, and P23. For this reason, when generating partial print data for printing the partial area NAx, the CPU 210 adjusts the recording rates R21 and R23 according to the length of the transport direction AR of the partial area NAx. Specifically, the longer the partial area NAx, the more gradual the fluctuations in the recording rates R21 and R23 with respect to their position in the transport direction AR are.

[0119] 16 and 17 is used as the basic configuration, and as the excess amount VO increases, the CPU 210 generates partial print data by decreasing the variable transport amount TVv. As a result, the length in the transport direction AR of the partial area NAx printed in the three partial printings at head positions P21, P22, and P23 performed after variable sheet transport T21B is maximized for the basic configuration, and decreases as the excess amount VO increases.

[0120] According to the second embodiment described above, the CPU 210 adjusts the variable transport amount TVv of the sheet transport T21B so that the upstream edge of the sheet M is positioned within the allowable range AA at the start position of a sheet transport (e.g., T31) that transports the sheet M by the large transport amount TVb (FIGS. 16 to 19). As a result, similar to the first embodiment, the position of the sheet M before and after the sheet transport T31 can be set to an appropriate position that jumps over the prohibited range NGA (FIGS. 16 to 19). Therefore, without excessively increasing the large transport amount TVb, it is possible to prevent the sheet M from coming into contact with the print head 110. In other words, it is possible to prevent the sheet M from coming into contact with the print head 110 while still achieving multi-pass printing. Furthermore, because it is possible to prevent an increase in the number of partial prints and the number of sheet transports, it is possible to prevent an increase in printing time.

[0121] More specifically, when the upstream edge of sheet M is at a first position (specifically, a position that is a distance da away from the allowable range AA (FIG. 16)) at the completion of sheet transport T16, CPU 210 sets the variable transport amount TVv of sheet transport T21B to a first amount (e.g., 3TVs) (FIGS. 16 and 17). Then, when the upstream edge of sheet M is at a second position that is downstream of the first position (specifically, a position that is a distance db away from the allowable range AA (FIG. 19)) at the completion of sheet transport T16, CPU 210 sets the variable transport amount TVv of sheet transport T21B to a second amount (e.g., TVs) that is smaller than the first amount (FIGS. 18 and 19). As a result, by reducing the variable transport amount TVv the more downstream the upstream edge of sheet M is at the completion of sheet transport T16, it is possible to position sheet M before and after sheet transport T31 at an appropriate position that jumps over the prohibited range NGA.

[0122] Furthermore, according to this embodiment, when the variable conveyance amount TVv of sheet conveyance T21B is set to a second amount smaller than the first amount, the range of nozzles NRa, NRb, and NRc used in the partial printing performed after sheet conveyance T21B (FIG. 20) is made shorter than when the variable conveyance amount TVv of sheet conveyance T21B is set to the first amount (FIG. 20). In other words, when the variable conveyance amount TVv is set to a second amount smaller than the first amount, the number of raster lines printed in the partial printing performed after sheet conveyance T21B is made smaller than when the variable conveyance amount TVv of sheet conveyance T21B is set to the first amount (FIG. 20). As a result, the control of partial printing that is changed in conjunction with shortening the variable conveyance amount TVv from the basic configuration only needs to reduce the number of raster lines processed compared to the control of the basic configuration. Therefore, changes to the variable conveyance amount TVv and the resulting changes to partial printing can be easily achieved. Furthermore, since the required memory capacity does not increase with a change in the variable transport amount TVv, if the required memory capacity is secured in the basic configuration, no memory capacity problems will arise.

[0123] Furthermore, multi-pass printing in this embodiment is printing in which the recording rate of at least some of the multiple partial prints that print a partial area (for example, the partial area NAx in FIG. 20) is varied according to the position in the transport direction AR (FIG. 20). When adjusting the variable transport amount TVv, the CPU 210 adjusts the recording rate in the partial print after sheet transport T21B at the variable transport amount TVv according to the adjustment of the variable transport amount TVv. Specifically, as described with reference to FIG. 20, the recording rates R21 and R23 when printing the partial area NAx, whose length in the transport direction AR varies according to the adjustment of the variable transport amount TVv, are adjusted. As a result, even when adjusting the variable transport amount TVv, multi-pass printing can be performed appropriately, and degradation of image quality due to banding, for example, can be suppressed.

[0124] As can be seen from the above explanation, in this embodiment, sheet transports T12 to T16 at the medium transport amount TVm are each an example of a first transport operation, sheet transport T21B at the variable transport amount TVv and sheet transports T22 and T23 at the small transport amount TVs are each an example of a second transport operation, and sheet transport T31 at the large transport amount TVb is an example of a third transport operation. Also, sheet transport T21B at the variable transport amount TVv is an example of a specific second transport operation.

[0125] C. Variations (1) In the above embodiments, multi-pass printing is used in which any number of consecutive raster lines in the transport direction AR are each printed in three partial prints. Alternatively, multi-pass printing may be used in which, of three consecutive raster lines in the transport direction AR, the first raster line is printed in a first partial print, the second raster line is printed in a second partial print, and the third raster line is printed in a third partial print. In this configuration, the printing resolution in the transport direction AR can be set to a resolution (e.g., 900 dpi) higher than the resolution (e.g., 300 dpi) corresponding to the nozzle spacing NT (FIG. 4).

[0126] Furthermore, the so-called number of passes in multi-pass printing (3 in this embodiment) may be 2 or an integer equal to or greater than 4. In other words, multi-pass printing may be employed in which each of multiple raster lines that are continuous in the transport direction AR is printed in two or four or more partial prints.

[0127] (2) In the first embodiment, the number of sheet transports at the small transport amount TVs is adjusted to adjust the paper positions before and after sheet transport T31 at the large transport amount TVb so that they jump over the prohibited range NGA. In the second embodiment, the variable transport amount TVv of sheet transport T21B is adjusted to adjust the paper positions before and after sheet transport T31 so that they jump over the prohibited range NGA. By combining the first and second embodiments, for example, by adjusting both the number of sheet transports at the small transport amount TVs and the transport amount of these sheet transports, the paper positions before and after sheet transport T31 may be adjusted so that they jump over the prohibited range NGA. For example, as in the first embodiment, the CPU 210 may roughly adjust the paper positions before and after sheet transport T31 by adjusting the number of sheet transports at the small transport amount, and further, as in the second embodiment, finely adjust the paper positions before and after sheet transport T31 by finely adjusting the transport amount of the first small transport amount of sheet transport.

[0128] (3) In the second embodiment, the variable conveyance amount TVv is adjusted in stages according to the excess amount VO. Alternatively, the variable conveyance amount TVv may be adjusted continuously according to the excess amount VO. For example, each time the excess amount VO decreases by one raster line, the variable conveyance amount TVv may be increased by one raster line.

[0129] (4) In the second embodiment, the number of times the sheet is conveyed at the small conveyance distance TVs is adjusted between 3 and 5 times. The adjustable number of times is not limited to this range and may be any range. The number of times the sheet is conveyed at the small conveyance distance TVs may be adjusted between 2 and 6 times, or between 4 and 7 times, for example.

[0130] (5) In the multi-pass printing of each of the above embodiments, the recording rate of each partial print varies depending on the position of the raster line to be printed in the transport direction AR (FIGS. 8 and 20). Alternatively, the recording rate of each partial print may be a fixed value (for example, 1 / 3) regardless of the position of the raster line to be printed in the transport direction AR.

[0131] (6) The specific configuration of the printer 200 described with reference to Figures 2 to 5 is an example and is not limited to this. For example, the sheet cutting unit 150 may be located at another position between the roll mounting unit 11 and the print head 110. For example, the sheet cutting unit 150 may be located between the pair of intermediate rollers 142 and the pair of conveying rollers 143, or may be attached to the guide member 147 or the guide member 148. Furthermore, the configuration for holding the paper M in a wavy state is not limited to the configuration shown in Figure 5, and other configurations may be adopted.

[0132] (7) The printing process of FIG. 6 and the print data output process of FIG. 15 are merely examples and are not limiting. For example, in the processes of FIGS. 6 and 15, the entire image data is converted into print data (S130 of FIG. 6), and then the print data output process of FIG. 15 is executed. Alternatively, for example, the print data conversion may be executed for each raster data each time raster data is acquired in S200 of FIG. 15. Also, in the print data output process, 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. Alternatively, the print data may be divided to generate all partial print data, and after the transport amounts for all sheet transports have been determined, the partial print data and the transport amount data may be output.

[0133] (8) As the printing medium, instead of paper M, other sheet-like printing media, such as a roll of resin film or cloth, may be used.

[0134] (9) In each of the above embodiments, the control device that executes the printing process of Fig. 6 is the CPU 210. Alternatively, the control device may be another type of device, for example, the 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 of Fig. 6 as part of its function as the printer driver. In this case, the terminal device supplies the partial print data and carry amount data to the printer 200 as a print execution unit, thereby causing the printer 200 to execute printing.

[0135] (10) The control device that executes the printing process in Fig. 6 may be, for example, a server that acquires image data from printer 200 or terminal device 300, uses the image data to generate the partial print data and carry amount data described above, and transmits this data to printer 200. Such a server may be multiple computers (so-called cloud servers) that can communicate with each other via a network.

[0136] (11) In each of the above embodiments, some of the hardware components may be replaced with software, and conversely, some or all of the software components may be replaced with hardware. For example, some of the printing process in FIG. 6 may be implemented by a dedicated hardware circuit (e.g., an ASIC) that operates according to instructions from the CPU 210.

[0137] 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 also included in the present invention. [Explanation of symbols]

[0138] 1...housing, 1...paper feed tray, 100...printing mechanism, 11...roller mounting section, 110...print head, 111...nozzle forming surface, 11x...recess, 11y...long hole, 120...head drive section, 130...main scanning section, 133...carriage, 134...sliding shaft, 14, 15...roller, 140...conveying section, 141...feed roller, 142...intermediate roller pair, 143...conveying roller pair, 144...paper discharge roller pair, 145...paper stand, 146...pressure member, 147, 147...guide member, 150... Sheet cutting unit, 151... cutter, 151a, 151b... rotary blades, 152... scanning mechanism, 200... printer, 210... CPU, 220... non-volatile storage device, 230... volatile storage device, 260... operation unit, 270... display unit, 280... communication unit, 3... arm, 300... terminal device, 3x... support shaft, 5... paper feed tray, 6... paper output tray, HP... high support member, HP... each support member, LP... low support member, M... paper, NZ... nozzle, PG... computer program, R... roll body

Claims

1. 1. A printing device, comprising: The housing and a mounting section to which a roll body is detachably mounted, the roll body being a wound sheet-like printing medium; a print head provided within the housing and having a plurality of nozzles that eject ink of a specific color, the plurality of nozzles being positioned at different positions in a transport direction of the print medium, and ejecting ink onto the print medium to form dots on the print medium; a transport unit configured to transport the print medium in the transport direction along a transport path that includes an upstream path from the mounting unit to the print head; a cutter that cuts the print medium at a specific position on the upstream path; a control unit that performs multi-pass printing in which partial printing, in which the print head forms the dots, and the transport unit transports the print medium, are alternately performed a plurality of times, thereby printing a plurality of consecutive raster lines in the transport direction by the partial printing a plurality of times; Equipped with the conveying unit includes a holding unit disposed in the upstream path at a position between the cutter and the print head, the holding section holds the print medium in a state in which the print medium is deformed in a wave shape along a direction perpendicular to the transport direction, The control unit a first transport operation for transporting the print medium and the partial printing after the first transport operation are performed a plurality of times; a second transport operation that transports the print medium by a transport amount smaller than that of the first transport operation, and the partial printing that follows the second transport operation; a third transport operation that transports the print medium by a transport amount greater than that of the first transport operation, and the partial printing that follows the third transport operation; the third transport operation transports the print medium from a start position where an upstream end of the print medium in the transport direction is held by the holding unit to an end position where the upstream end is not held by the holding unit; the control unit adjusts at least one of the number of times the second transport operation is performed and the transport amount of the second transport operation so that the upstream edge of the print medium is positioned within a specific range at the start position of the third transport operation; The specific range is a range in the transport direction that is determined with respect to the holding unit.

2. 2. The printing device according to claim 1, The control unit adjusts the number of times the second transport operation is performed so that the upstream edge of the print medium is positioned within a specific range at the start position of the third transport operation.

3. 3. The printing device according to claim 2, The control unit When the upstream edge of the print medium is at a first position upon completion of the first transport operation, the second transport operation is performed N times (N is an integer greater than or equal to 1); A printing device that performs the second transport operation M times (M is an integer satisfying M>N) when the upstream end of the printing medium is at a second position upstream of the first position at the completion of the first transport operation.

4. 4. The printing device according to claim 3, The conveying amount of the N number of the second conveying operations is the same as the conveying amount of the M number of the second conveying operations.

5. 5. The printing device according to claim 4, when the control unit executes the M number of second transport operations, it adds (M-N) number of second transport operations after the N number of second transport operations; A printing device in which the plurality of nozzles used in the partial printing performed after each of the additional (M-N) second transport operations are the same as the plurality of nozzles used in the partial printing performed after the last transport operation of the N second transport operations.

6. 2. The printing device according to claim 1, The control unit adjusts the transport amount of the second transport operation so that the upstream edge of the print medium is positioned within a specific range at the start position of the third transport operation.

7. 7. The printing device according to claim 6, The control unit When the upstream edge of the printing medium is at a first position upon completion of the first transport operation, a transport amount of the specific second transport operation is set to a first amount; A printing device that sets the transport amount of the specific second transport operation to a second amount smaller than the first amount when the upstream end of the printing medium is at a second position downstream of the first position at the completion of the first transport operation.

8. 8. The printing device according to claim 7, a control unit that, when setting the transport amount of the specific second transport operation to the second amount, reduces the number of raster lines printed in the partial printing performed after the second transport operation compared to when setting the transport amount of the specific second transport operation to the first amount.

9. The printing device according to any one of claims 6 to 8, the multi-pass printing is a printing method in which a recording rate of at least a part of the partial printing performed multiple times to print a specific area is changed according to a position in the transport direction, When adjusting the carry amount of the second transport operation, the control unit adjusts the recording rate of the partial printing after the second transport operation in accordance with the adjustment of the carry amount.

10. The printing device according to any one of claims 1 to 9, the holding section includes a plurality of ribs positioned at different positions in a specific direction perpendicular to the transport direction, the plurality of ribs supporting the print medium from below, and a plurality of pressing members positioned at different positions in the specific direction, the plurality of pressing members pressing the print medium from above, A printing device, wherein the positions of the plurality of pressing members in the specific direction are each located between two of the plurality of ribs that are adjacent to each other in the specific direction.

11. A computer program for controlling a printing device, comprising: The printing device The housing and a print head provided within the housing; a mounting section to which a roll body is detachably mounted, the roll body being a wound sheet-like printing medium; a transport unit configured to transport the print medium in a transport direction along a transport path including an upstream path from the mounting unit to the print head; a cutter that cuts the print medium at a specific position on the upstream path; Equipped with the conveying unit includes a holding unit disposed in the upstream path at a position between the cutter and the print head, the holding section holds the print medium in a state in which the print medium is deformed in a wave shape along a direction perpendicular to the transport direction, the print head has 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 ejects ink onto the print medium to form dots on the print medium; the computer program causes a computer to realize a control function that causes the printing device to perform multi-pass printing in which a plurality of raster lines that are continuous in the transport direction are printed by a plurality of partial printings, by alternately performing a plurality of partial printings in which the print head forms the dots and a plurality of transporting steps of the print medium by the transport unit; The control function is a first transport operation for transporting the print medium and the partial printing after the first transport operation are performed a plurality of times; a second transport operation that transports the print medium by a transport amount smaller than that of the first transport operation, and the partial printing that follows the second transport operation; a third transport operation that transports the print medium by a transport amount greater than that of the first transport operation, and the partial printing that follows the third transport operation; the third transport operation transports the print medium from a start position where an upstream end of the print medium in the transport direction is held by the holding unit to an end position where the upstream end is not held by the holding unit; the control function adjusts at least one of the number of times the second transport operation is performed and the transport amount of the second transport operation so that the upstream edge of the print medium is positioned within a specific range at the start position of the third transport operation; The specific range is a range in the conveying direction that is determined with respect to the holding unit.

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