JP2020049762A - Image processing system and computer program - Google Patents

Abstract

To hinder delay of supply of ink.SOLUTION: Using image data, an image processing system performs printing by conducting, two or more times: partial printing in which ink is ejected by a print head while main scanning is carried out by a main scanning unit; and sub-scanning carried out by a sub-scanning unit. In the case of a first situation in which specific condition is not satisfied, which indicates that supply of ink to a print head from an ink supply unit is delayed in partial printing, the specific condition being judged for each belt-like partial image extending from one end to the other end in a main scanning direction of a print image, the image processing system causes the partial image to be printed in partial printing at one time. In the case of a second situation in which the specific condition is satisfied, a first portion of the partial image, in which the portion includes one end and does not include the other end in the main scanning direction, is printed by first partial printing, and a second portion of the partial image, which includes the other end and does not include one end in the main scanning direction, is printed in second partial printing.SELECTED DRAWING: Figure 13

Description

  The present specification relates to image processing for a print execution unit that can form a plurality of types of dots on a print medium.

  2. Description of the Related Art A printer that prints an image by discharging ink from nozzles of a print head is known. In these printers, for example, when the temperature of the ink is relatively low, the viscosity of the ink increases, so that a delay in the supply of the ink from the ink storage unit to the print head is likely to occur. When a delay in ink supply occurs, the image quality deteriorates due to, for example, a light color of a printed image.

  Patent Literature 1 discloses a technique of increasing the number of passes for printing a band when the number of continuous ejections of dots counted in the band is larger than a threshold value corresponding to the temperature of the print head.

JP-A-2004-66550

  However, the above technique does not disclose a specific means for increasing the number of passes for printing a band.

  This specification discloses a new technique capable of suppressing a delay in ink supply.

  The technology disclosed in this specification can be realized as the following application examples.

Application Example 1 A print head having a plurality of nozzles for discharging ink, an ink supply unit for supplying the ink to the print head, and moving the print head along a main scanning direction with respect to a print medium A print execution unit including: a main scanning unit that performs a main scan; and a sub scanning unit that performs a sub scan that moves the print medium along a sub scanning direction that intersects the main scanning direction with respect to the print head. An image processing apparatus for acquiring an image data, and using the image data, partial printing that causes the main scanning unit to perform the main scanning while discharging the ink to the print head. Causing the sub-scanning unit to perform the sub-scanning; and performing a plurality of times to perform the printing by the print execution unit. The print control unit includes: Scan direction The specific condition that is determined for each of the band-shaped partial images extending from one end to the other end and that indicates that the supply of the ink from the ink supply unit to the print head may be delayed in the partial printing is satisfied. In the first case where the partial image is not printed, the partial image is printed by one time of the partial printing, and in the second case where the specific condition is satisfied, the one end of the partial image in the main scanning direction is A first part including the other end and not including the other end is printed by the first partial printing, and a second part of the partial image including the other end in the main scanning direction and not including the one end is defined as a second part. An image processing apparatus for printing by the partial printing.

  According to the above configuration, the print control unit, in the second case, in which the specific condition indicating that the supply of the ink from the ink supply unit to the print head may be delayed in the partial print is not satisfied, the print control unit performs the partial image once. In the second case where the printing is performed by the partial printing and the specific condition is satisfied, the first part including one end and not including the other end of the partial image is printed by the first partial printing and includes the other end. The second part not including one end is printed by the second part printing. As a result, in the second case, a delay in ink supply can be suppressed.

  The technology disclosed in the present specification can be realized in various forms, for example, a printing apparatus, a control method of a print execution unit, a printing method, and a computer program for realizing the functions of these apparatuses and methods. , A recording medium on which the computer program is recorded, and the like.

FIG. 2 is a block diagram illustrating a configuration of a printer according to the embodiment. FIG. 2 is a diagram illustrating a schematic configuration of a printing mechanism. FIG. 3 is a diagram illustrating a configuration of the print head 110 viewed from the −Z side. FIG. 3 is a diagram showing a schematic configuration of a transport unit 140. FIG. 4 is an explanatory diagram of the operation of the printing mechanism 100. 6 is a flowchart of image processing according to the embodiment. 6 is a flowchart of image processing according to the embodiment. 6 is a flowchart of image processing according to the embodiment. 6 is a flowchart of image processing according to the embodiment. FIG. 7 is a diagram illustrating an example of a threshold table TT. It is a flowchart of a specific condition determination process. FIG. 4 is a diagram illustrating blocks set in a partial image. FIG. 4 is a diagram illustrating an example of partial printing. FIG. 4 is a diagram illustrating an example of partial printing. FIG. 4 is a diagram illustrating an example of partial printing. FIG. 4 is a diagram illustrating an example of partial printing. FIG. 4 is a diagram illustrating an example of partial printing. It is explanatory drawing of determination of the division | segmentation position of a modification. It is explanatory drawing of determination of the division | segmentation position of a modification.

A. Example:
A-1: Configuration of Printer 200 Next, an embodiment will be described based on an example. FIG. 1 is a block diagram illustrating a configuration of the printer 200 according to the embodiment.

  The printer 200 includes, for example, a printing mechanism 100, a CPU 210 as a controller of the printer 200, a nonvolatile storage device 220 such as a hard disk drive, a volatile storage device 230 such as a RAM, and buttons for acquiring user operations. An operation unit 260 such as a touch panel or a touch panel, a display unit 270 such as a liquid crystal display, and a communication unit 280 are provided. Communication unit 280 includes a wired or wireless interface for connecting to network NW. The printer 200 is communicably connected to an external device, for example, the terminal device 300 via the communication unit 280.

  The volatile storage device 230 provides a buffer area 231 for temporarily storing various intermediate data generated when the CPU 210 performs processing. The non-volatile storage device 220 stores a computer program PG and a threshold table TT. The computer program PG is a control program for controlling the printer 200 in this embodiment. The computer program PG and the threshold table TT can be stored and provided in the nonvolatile storage device 220 when the printer 200 is shipped. Instead, the computer program PG and the threshold table TT may be provided in a form downloaded from a server, or may be provided in a form stored in a DVD-ROM or the like. The CPU 210 executes, for example, image processing described later by executing the computer program PG. Accordingly, the CPU 210 controls the printing mechanism 100 to print an image on a print medium (for example, paper). The threshold table TT will be described later.

  The printing mechanism 100 can form dots on the paper M using the respective inks (droplets) of cyan (C), magenta (M), yellow (Y), and black (K). I do. The printing mechanism 100 includes a print head 110, a head driving unit 120, a main scanning unit 130, a transport unit 140, an ink supply unit 150, and a temperature sensor 170.

  FIG. 2 is a diagram illustrating a schematic configuration of the printing mechanism 100. As shown in FIG. 2, the main scanning unit 130 includes a carriage 133, a slide shaft 134, a belt 135, and a plurality of pulleys 136 and 137. The carriage 133 has the print head 110 mounted thereon. The sliding shaft 134 holds the carriage 133 so as to be able to reciprocate along the main scanning direction (the X-axis direction in FIG. 2). The belt 135 is wound around pulleys 136 and 137, and a part of the belt 135 is fixed to the carriage 133. The pulley 136 is rotated by the power of a main scanning motor (not shown). When the main scanning motor rotates the pulley 136, the carriage 133 moves along the sliding shaft 134. As a result, main scanning in which the print head 110 reciprocates with respect to the sheet M along the main scanning direction is realized.

  The ink supply unit 150 supplies ink to the print head 110. The ink supply section 150 includes a cartridge mounting section 151, a tube 152, and a buffer tank 153. A plurality of ink cartridges KC, CC, MC, and YC, which are containers containing ink therein, are removably mounted on the cartridge mounting section 151, and ink is supplied from these ink cartridges. The buffer tank 153 is disposed above the print head 110 on the carriage 133, and temporarily stores ink to be supplied to the print head 110 for each CMYK ink. The tube 152 is a flexible tube that serves as an ink flow path that connects between the cartridge mounting unit 151 and the buffer tank 153. The ink in each ink cartridge is supplied to the print head 110 via the cartridge mounting section 151, the tube 152, and the buffer tank 153. The buffer tank 153 is provided with a filter (not shown) for removing foreign matter mixed in the ink.

  FIG. 3 is a diagram illustrating a configuration of the print head 110 as viewed from the −Z side. As shown in FIG. 3, the nozzle forming surface 111 of the print head 110 is a surface facing the paper M transported by the transport unit 140. A plurality of nozzle rows composed of a plurality of nozzles NZ, that is, nozzle rows NC, NM, NY, and NK that eject the respective inks of C, M, Y, and K are formed on the nozzle forming surface 111. Each nozzle row includes a plurality of nozzles NZ. The plurality of nozzles NZ have different positions in the transport direction (+ Y direction), and are arranged at a predetermined nozzle interval NT along the transport direction. The nozzle interval NT is the length in the transport direction between two nozzles NZ adjacent in the transport direction among the plurality of nozzles NZ. Of the nozzles forming these nozzle rows, the nozzle NZ located on the most upstream side (−Y side) is also referred to as the most upstream nozzle NZu. Further, among these nozzles, the nozzle NZ located on the most downstream side (+ Y side) is referred to as the most downstream nozzle NZd. The length obtained by adding the nozzle interval NT to the length in the transport direction from the most upstream nozzle NZu to the most downstream nozzle NZd is also referred to as a nozzle length D.

  The positions of the nozzle rows NC, NM, NY, and NK in the main scanning direction are different from each other, and the positions in the sub-scanning direction overlap each other. For example, in the example of FIG. 3, the nozzle row NM is arranged in the + X direction of the nozzle row NY for discharging the Y ink.

  Each nozzle NZ is connected to the buffer tank 153 via an ink flow path (not shown) formed inside the print head 110. An actuator (not shown, a piezoelectric element in this embodiment) for discharging ink along each ink flow path inside the print head 110 is provided.

  The head drive unit 120 (FIG. 1) drives each actuator in the print head 110 in accordance with print data supplied from the CPU 210 during main scanning by the main scanning unit 130. Accordingly, ink is ejected from the nozzles NZ of the print head 110 on the paper M conveyed by the conveyance unit 140, and dots are formed. The configuration of the head driving unit 120 will be described later. The head drive unit 120 can form dots of a plurality of sizes on the paper M by changing the drive voltage supplied to the actuator. Specifically, the head drive unit 120 can form dots of four types of sizes of “small”, “medium”, “large”, and “extra large” in ascending order.

  The temperature sensor 170 is a known temperature sensor including a resistance temperature detector and the like, and is installed near the print head 110 of the printer 200. The temperature sensor 170 outputs a signal indicating the temperature of the print head 110 of the printer 200.

  The transport unit 140 transports the paper M in the transport direction (+ Y direction in FIG. 2) while holding the paper M. FIG. 4 is a diagram illustrating a schematic configuration of the transport unit 140. As shown in FIG. 4A, the transport unit 140 includes a sheet table 141, an upstream roller pair 147 for holding and transporting the sheet, a downstream roller pair 148, and a plurality of pressing members 146. Have.

  The upstream roller pair 147 is provided on the upstream side (−Y side) in the transport direction of the print head 110, and the downstream roller pair 148 is provided on the downstream side (+ Y side) of the print head 110 in the transport direction. . The upstream roller pair 147 includes a drive roller 147a driven by a transport motor (not shown), and a driven roller 147b that rotates according to the rotation of the drive roller 147a. Similarly, the downstream roller pair 148 includes a driving roller 148a and a driven roller 148b. Note that a plate member may be employed instead of the driven roller, and a configuration in which the sheet is held by the drive roller and the plate member may be employed.

  The paper table 141 is disposed between the upstream roller pair 147 and the downstream roller pair 148 and at a position facing the nozzle forming surface 111 of the print head 110. The plurality of holding members 146 are disposed between the upstream roller pair 147 and the print head 110.

  FIGS. 4B and 4C are perspective views of the sheet table 141 and the plurality of pressing members 146. FIG. FIG. 4B illustrates a state where the sheet M is not supported, and FIG. 4C illustrates a state where the sheet M is supported. The paper table 141 includes a plurality of high support members 142, a plurality of low support members 143, and a flat plate 144.

  The flat plate 144 is a plate member substantially parallel to the main scanning direction (X direction) and the transport direction (+ Y direction). The end on the −Y side of the flat plate 144 is located near the upstream roller pair 147. The end on the + Y side of the flat plate 144 is located near the downstream roller pair 148.

  The plurality of high support members 142 and the plurality of low support members 143 are alternately arranged on the flat plate 144 along the X direction. That is, each low support member 143 is disposed between two high support members 142 adjacent to the low support member. Each high support member 142 is a rib extending along the Y direction. The −Y side end of each high support member 142 is located at the −Y side end of the flat plate 144. The + Y side end of each high support member 142 is located at the center of the flat plate 144 in the Y direction. The positions of both ends of each low support member 143 in the Y direction are the same as the positions of both ends of the high support member 142 in the Y direction.

  The plurality of holding members 146 are arranged at positions on the + Z side of the plurality of low support members 143. The positions of the plurality of pressing members 146 in the X direction are the same as the positions of the plurality of low support members 143 in the X direction. That is, the position of each pressing member 146 in the X direction is located between the two high support members 142 adjacent to the pressing member. The plurality of pressing members 146 are plate members that are inclined so as to approach the low support member 143 as going in the + Y direction. The + Y side ends of the plurality of holding members 146 are located between the −Y side ends of the print head 110 and the upstream roller pair 147.

  The plurality of high support members 142, the plurality of low support members 143, and the plurality of pressing members 146 are disposed closer to the upstream roller pair 147 than the downstream roller pair 148. It can be said that it is provided on the upstream roller pair 147 side among the pair 148.

  As shown in FIG. 4C, when the paper M is transported, the plurality of high support members 142 and the plurality of low support members 143 support the paper M from the surface Mb opposite to the printing surface. The plurality of pressing members 146 support the paper M from the printing surface Ma side. As described above, the plurality of high support members 142, the plurality of low support members 143, and the plurality of pressing members 146 cause the sheet M to move in the X direction at a position facing the nozzle forming surface 111 of the print head 110. (FIG. 4 (C)). Then, the sheet M is transported in the transport direction (+ Y direction) in a state of being deformed in a wavy shape. When the sheet M is deformed in a wave shape, the rigidity of the sheet M against deformation along the Y direction can be increased. As a result, the sheet M is deformed so as to be warped along the Y direction, and the sheet M is prevented from floating from the sheet table 141 to the print head 110 side and the sheet M from being drooping toward the sheet table 141 side. Can be. When the paper M rises or the paper M hangs, a shift in the dot formation position may cause deterioration in the image quality of the printed image, for example, image quality deterioration due to banding. When the paper M rises, the paper comes into contact with the print head 110, and the paper M may be stained.

  Here, the sheet M deformed in a wavy shape extends along the transport direction (Y direction) and includes a plurality of peaks PP arranged in the main scanning direction (X direction) (FIG. 4C). The plurality of high support members 142 support each of the plurality of peaks PP from the side opposite to the side where the print head 110 is located. Further, the paper M deformed in a wavy shape extends along the transport direction (Y direction) and includes a plurality of valleys VP arranged in the main scanning direction (X direction) (FIG. 4C). The plurality of peaks PP and the plurality of valleys VP are alternately arranged in the X direction. The plurality of low support members 143 support each of the plurality of valleys VP from the side opposite to the side where the print head 110 is located. In FIG. 4, the number of the high support members 142 and the number of the peaks PP are five in order to avoid complication of the drawing. However, actually, a large number (nine in this embodiment) of the high support members 142 is provided. And a peak PP. The same applies to the low support member 143, the holding member 146, and the valley VP.

A-2. Overview of Printing The CPU 210 causes the main scanning unit 130 to perform main scanning while discharging ink from the print head 110 to form dots on the paper M, and sub-scanning by the transport unit 140 (transportation of the paper M). Are executed a plurality of times alternately to print a print image on the paper M.

  FIG. 5 is an explanatory diagram of the operation of the printing mechanism 100. FIG. 5 shows a print image OI to be printed on the paper M. The print image OI includes a plurality of partial images PI1 to PI5. Each partial image is an image printed by one partial printing in principle. However, although the details will be described later, there is a case where one partial image is printed by two partial printings. The printing direction of the partial printing is one of the forward direction and the backward direction. That is, the partial printing includes forward printing in which dots are formed while performing main scanning in the forward direction (+ X direction in FIG. 5), and return printing in which dots are formed while performing main scanning in the backward direction (−X direction in FIG. 5). And printing.

  In FIG. 5, at least one arrow in the + X direction or the −X direction is given in the partial image. The partial images PI1 and PI4 with one arrow in the + X direction are forward pass partial images printed by one forward pass printing. The partial images PI2 and PI5 provided with one arrow in the −X direction are return path partial images printed by one return path printing. The hatched partial image PI3 has two arrows in the + X direction and the -X direction. The partial image PI3 is a reciprocating partial image that is printed by two partial printings including one forward printing and one returning printing.

  As shown in FIG. 5, the printing of this embodiment is, in principle, bidirectional printing in which forward printing and backward printing are alternately executed. In the bidirectional printing, for example, the printing time can be reduced as compared with the one-way printing in which only the forward pass printing is repeatedly executed. In one-way printing, it is necessary to move the print head 110 in the backward direction without performing partial printing in order to perform the forward printing again after the forward printing, but in bidirectional printing, it is not necessary. It is.

  In FIG. 5, an arrow in the −Y direction from one partial image (for example, the partial image PI1) to another partial image (for example, the partial image PI2) adjacent in the −Y direction indicates the conveyance of the paper M (the sub-image). Scanning). That is, the arrow in the −Y direction in FIG. 5 indicates that the print head 110 moves in the −Y direction with respect to the sheet M illustrated in FIG. As shown in FIG. 5, the printing of the present embodiment is, in principle, a so-called one-pass printing, and the length of each partial image in the transport direction and the transport amount of the paper M at one time are determined by the nozzle length D. is there. However, as in the case of the partial image PI3 described above, in a specific case, printing may be performed by two partial printings (details will be described later).

  Here, when the ink is ejected from the nozzles NZ during printing, the amount of ink in the buffer tank 153 (FIG. 2) decreases by the amount of the ejected ink, so that a negative pressure is generated in the buffer tank 153. By the negative pressure, ink is supplied from the ink cartridge to the buffer tank 153 via the cartridge mounting portion 151 and the tube 152. If a large amount of ink is ejected from the plurality of nozzles NZ within a short time for printing, a delay in the supply of ink to the buffer tank 153 may occur. If such a delay in the supply of ink occurs, there occurs a problem that the ink is not ejected from the nozzle NZ or a smaller amount of ink is ejected than expected even when the actuator is driven. When such a problem occurs, the color of the print image OI becomes lighter, and the image quality deteriorates.

  The delay in the supply of ink is likely to occur when the fluidity of the ink decreases. For example, the lower the temperature of the print head 110 of the printer 200 (printing mechanism 100) (hereinafter, also referred to as the head temperature Th), the more likely the ink supply delay will occur. This is because the lower the head temperature Th, the higher the viscosity of the ink, and the lower the flowability of the ink. Here, the cumulative ink usage TA is an index value indicating the cumulative usage of a specific ink (any of C, M, Y, and K) from the time of manufacturing the printer 200 to the present. As the cumulative ink usage amount TA increases, the supply delay of the specific ink is more likely to occur. This is because the larger the cumulative ink usage amount TA, the larger the amount of foreign matter deposited on the filter for removing foreign matter in the ink, so that the flow resistance of the ink increases and the fluidity of the ink decreases. The pass ink usage PA is an index value indicating the usage of a specific ink used for printing a partial image in one partial printing. As the pass ink usage PA increases, the supply delay of the specific ink is more likely to occur. This is because the specific ink is used in a short time, so that the supply of the specific ink tends to be difficult to keep up with.

  In the image processing described below, a contrivance is made to suppress a delay in ink supply. Specifically, when printing a specific partial image (partial image PI3 in the example of FIG. 5) that satisfies a specific condition indicating that a delay in ink supply is likely to occur, as described above, two times The specific partial image is printed by the partial printing. This makes it possible to reduce the amount of ink used in one partial print as compared with the case where a specific partial image is printed in one partial print. Therefore, it is possible to suppress a large amount of ink from being used in a short time when a specific partial image is printed, and to suppress a delay in ink supply when a specific partial image is printed. be able to.

A-3. Image Processing FIGS. 6 to 9 are flowcharts of image processing of the embodiment. FIG. 10 is a diagram illustrating an example of the threshold table TT. The CPU 210 of the printer 200 starts image processing, for example, when receiving a print instruction from the terminal device 300 (FIG. 1). Alternatively, the CPU 210 may start image processing when a print instruction is obtained from the user via the operation unit 260. The print instruction includes designation of image data indicating an image to be printed.

  In S100, the CPU 210 controls the transport unit 140 to transport one sheet of paper M from a print tray (not shown) to a predetermined initial position.

  In S105, the CPU 210 acquires the head temperature Th of the print head 110 of the printer 200 based on the signal from the temperature sensor 170.

  In S110, the CPU 210 acquires the accumulated ink usage amount TA of each ink used for printing from the nonvolatile storage device 220. The cumulative ink usage amount TA is recorded in a predetermined area of the nonvolatile storage device 220 for each of the CMYK inks. The CPU 210 updates the cumulative ink usage amount TA by calculating the usage amount of each color ink based on, for example, the number of dots formed by printing each time printing is performed. In this step, for example, in the case of monochrome printing, the cumulative ink usage amount TA of the K ink is obtained, and in the case of color printing, the cumulative ink usage amount TA of each of the CMYK inks is obtained.

  In S115, the CPU 210 acquires a determination threshold value JT (unit:%) corresponding to each ink used for printing from the threshold value table TT in FIG. 10 based on the head temperature Th and the cumulative ink usage amount TA. In the threshold table TT, a determination threshold JT corresponding to a combination of the head temperature Th and the cumulative ink usage TA is recorded. For example, in the example of FIG. 10A, the acquired head temperature Th is within a predetermined “medium” range, and the accumulated ink usage amount TA acquired for a specific ink is a predetermined amount. If it is within the range of “large”, “75%” is acquired as the determination threshold value JT corresponding to the specific ink. In the case of monochrome printing, a determination threshold value JT corresponding to K ink is obtained, and in the case of color printing, one determination threshold value JT corresponding to all CMYK inks is obtained.

  In S120, the CPU 210 acquires dot data corresponding to the focused partial image among the plurality of partial images PI1 to PI5 of the print image OI from the image data as focused dot data, and stores it in the buffer area 331. . In this embodiment, the dot data is data indicating a dot formation state for each color component and for each pixel. The dot formation state is, for example, any one of “with dot” and “without dot”. Instead, the dot formation state may be any of “large dot”, “medium dot”, “small dot”, and “no dot”. Note that, in a modification, the CPU 210 may acquire the dot data of interest by generating the dot data of interest using the image data stored in the volatile storage device 230. For example, target dot data is generated by executing image processing including color conversion processing and halftone processing on data corresponding to the target partial image in the image data. Note that partial printing for printing the target partial image is also referred to as target partial printing.

  In S125, the CPU 210 executes the specific condition determination process on the target partial image using the target dot data. The specific condition determination processing determines whether or not a partial image to be processed (for example, a partial image of interest) satisfies a specific condition indicating that a delay in ink supply is likely to occur. If satisfies the above, the process is also to determine the division position of the partial image of interest. The division position is a position where the partial image to be processed is divided when the partial image to be processed is to be printed by two partial printings.

  FIG. 11 is a flowchart of the specific condition determination process. FIG. 12 is a diagram illustrating blocks set in a partial image. In S300, the CPU 210 divides the partial image to be processed into a plurality of blocks BL. For example, the partial image PI2 shown in FIG. 12 is divided into ten rectangular blocks BL arranged in the main scanning direction (X direction). The boundary BD between two blocks BL adjacent to each other corresponds to each peak PP of the sheet M that is deformed in a wave shape as described above when the print image OI including the partial image PI2 is printed on the sheet M. Set to position. In other words, the positions in the X direction of the nine boundaries BD of the partial image PI1 correspond to the positions on the paper M supported by the nine high support members 142 (FIG. 4C) at the time of printing. ing.

  In S305, the CPU 210 selects one target block from the ten blocks BL set in the partial image to be processed. The block of interest is selected from the upstream side in the printing direction (forward direction (+ X direction) or backward direction (-X direction)) of the first partial printing for printing the partial image to be processed. For example, in the example of FIG. 12, it is assumed that the printing direction of the partial image PI1 printed immediately before the partial image PI2 to be processed is the backward direction. In this case, since the printing direction of the first partial printing for printing the partial image PI2 to be processed is the forward direction, the target block is sequentially selected from the upstream side (−X side) in the forward direction. That is, in this case, the first block of interest is the block BLa located at the end on the −X side (FIG. 12). Hereinafter, the upstream side (−X side) in the forward path direction is simply referred to as the upstream side, and the downstream side (+ X side) in the forward path direction is simply referred to as the downstream side.

  In S310, the CPU 210 calculates the number of dot pixels (also referred to as the dot number Dp) in the target block for each ink used for printing. The dot pixel is a pixel having a value indicating dot formation in the target dot data. In the case of monochrome printing, the number of dots Dp corresponding to K ink is calculated, and in the case of color printing, the number of dots Dp of four dots corresponding to each ink of CMYK is calculated.

  In S320, the CPU 210 updates the total dot number Dt by adding the dot number Dp of the target block to the total dot number Dt of the already processed block. For example, when the target block is the block BLc in FIG. 12, the total number of dots of the three blocks BLa to BLc is calculated as a new total dot number Dt. Since the larger the dot number Dt is, the larger the pass ink usage amount PA is, the total dot number Dt is an index value indicating the pass ink usage amount PA. In the case of monochrome printing, the total number of dots Dt corresponding to K ink is calculated, and in the case of color printing, the total number of four dots Dt corresponding to each ink of CMYK is calculated.

  In S330, the CPU 210 determines whether or not the total dot number Dt of at least one ink used for printing is larger than the reference number Tv. The reference number Tv is the number of pixels of the processing target partial image corresponding to the determination threshold value JT (unit is%) acquired in S115 of FIG. For example, when the total number of pixels of the partial image to be processed is Pt, the reference number Tv is a number obtained by multiplying the total number of pixels Pt by the determination threshold value JT and dividing by 100 (Tv = (JT × Pt) / 100). ). When the total number of dots Dt is larger than the reference number Tv, a large amount of ink is ejected in a short time, so that a delay in ink supply may occur.

  If the total number of dots Dt is greater than the reference number Tv for at least one ink used for printing (S330: YES), it is determined in S340 that the partial image to be processed satisfies the specific condition. In S350, the CPU 210 determines the boundary BD between the current block of interest and the immediately preceding block of interest (also referred to as the immediately preceding block) as the division position DP, and ends the specific condition determination processing. For example, when the block BLe in FIG. 12 is the target block, the boundary BDd between the block BLd and the block BLe is determined as the division position DP.

  If the total number of dots Dt is equal to or smaller than the reference number Tv for all the inks used for printing (S330: NO), in S370, the CPU 210 determines that the partial image to be processed does not satisfy the specific condition. Then, the specific condition determination process ends.

  When the specific condition determination process is completed, it is determined in S130 of FIG. 6 whether or not the specific condition determination process determines that the specific condition is satisfied. If it is determined that the specific condition is satisfied (S130: YES), the supply of the ink may be delayed. Therefore, in order to suppress the delay of the supply of the ink, the target partial image is printed by two partial printings. You. For example, when the partial image PI2 of FIG. 12 is the focused partial print, the first partial FP of the partial image PI2 is printed by the first partial print, and the second partial SP is printed by the subsequent partial print. Is done. Then, the intermediate portion MP located between the first portion FP and the second portion SP is printed by both of the two partial printings. The first portion FP is, for example, a portion from the upstream end (left end in FIG. 12) in the printing direction (the forward direction (+ X direction in the example of FIG. 12)) to a position one block upstream of the division position DP. It is. The second part SP is, for example, a part from the division position DP to the downstream end (the right end in FIG. 12) in the printing direction.

  Specifically, first, in S135, CPU 210 executes a mask process. For example, the mask process is a process of allocating a plurality of pixels in the intermediate portion MP to one of two partial printings using mask data (not shown) stored in advance. The mask data is binary data corresponding to the intermediate portion MP, and is data that defines pixels to be assigned to the preceding partial printing and pixels to be assigned to the subsequent partial printing. For example, in the intermediate portion MP, pixels to be assigned to the preceding partial printing and pixels to be assigned to the subsequent partial printing are dispersedly arranged throughout the intermediate portion MP. For example, the closer to the first part FP, the higher the ratio of pixels allocated to the first partial printing, and the closer to the second part SP, the higher the ratio of pixels allocated to the subsequent partial printing.

  In S140, the CPU 210 causes the printing mechanism 100 to print the upstream portion of the target partial image. That is, the CPU 210 controls the head driving unit 120 and the main scanning unit 130 to execute the preceding partial printing, and the first part FP and the pixels allocated to the earlier partial printing of the intermediate part MP are displayed. Are formed on the paper M.

  13 to 17 are diagrams illustrating an example of partial printing. In FIG. 13, each arrow along the X direction on the partial image PI2 indicates a main scan performed in one partial print. Of the arrows, a solid line indicates a section in which dot formation is performed, and a broken line indicates a section in which dot formation is not performed. An arrow AR1 in FIG. 13 indicates partial printing before printing the partial image PI2. As shown by the arrow AR1, in the example of FIG. 13, the preceding partial printing is printing in the forward direction, and prints the first part FP and a part of the intermediate part MP of the partial image PI2.

  In S145, the CPU 210 executes a specific condition determination process on the next partial image. That is, a partial image (for example, the partial image PI3 in FIG. 12) adjacent to the target partial image (for example, the partial image PI2 in FIG. 13) on the upstream side (−Y side in FIG. 13) in the transport direction is processed. The above-described specific condition determination process (FIG. 11) is executed as the partial image. As a result, it is determined whether or not the next partial image satisfies the specific condition, and if the next partial image satisfies the specific condition, the division position DPn of the next partial image is determined.

  When the specific condition determination processing is completed, it is determined in S150 whether the specific condition determination processing determines that the specific conditions are satisfied for the next partial image. If it is determined that the specific condition is satisfied (S150: YES), the supply of ink may be delayed when printing the next partial image, so the next partial image is printed by two partial printings. . For example, when the partial image PI3 in FIG. 13 is the next partial print, the first part FPn and the second part SPn of the partial image PI3 are printed by different partial prints. Then, the intermediate portion MPn located between the first portion FPn and the second portion SPn is printed by both of the two partial printings.

  Specifically, first, in S155, the CPU 210 determines whether or not the downstream portion of the target partial image and the upstream portion of the next partial image can be printed. The downstream portion of the target partial image includes, for example, in the example of the partial image PI2 in FIG. 13, the second portion SP and the pixels assigned to the subsequent partial printing of the intermediate portion MP. In the example of the partial image PI3 in FIG. 13, the upstream portion of the next partial image includes the first portion FPn and the pixels of the intermediate portion MPn to be assigned to the previous partial printing. In the next partial image (for example, the partial image PI3 in FIG. 13), an area from the position on the left side of the left end LP of the downstream portion of the target partial image (for example, the partial image PI2 in FIG. 13) by one block to the right end. IAa is an area that cannot be printed together with the downstream portion of the target partial image. If the area IAa does not include at least a part of the upstream part (the first part FPn and the intermediate part MPn) of the next partial image, the upstream part of the next partial image is displayed together with the downstream part of the target partial image. It is determined that printing is possible. In the example of FIG. 13, the part of the first part FPn and the intermediate part MPn of the next partial image (partial image PI3) are located in the area IAa. It is determined that the upstream part of the partial image cannot be printed.

  If the upstream portion of the next partial image cannot be printed together with the downstream portion of the target partial image (S155: NO), in S160, the CPU 210 proceeds to S160. The printing mechanism 100 prints the downstream portion. That is, the CPU 210 controls the head driving unit 120 and the main scanning unit 130 to execute the subsequent partial printing, and the second part SP and the pixels assigned to the preceding partial printing of the intermediate part MP, Are formed on the paper M. An arrow AR2 in FIG. 13 indicates partial printing after the partial image PI2 is printed. As shown by the arrow AR2, in the example of FIG. 13, the subsequent partial printing is printing in the backward direction, and prints the second part SP and a part of the intermediate part MP of the partial image PI2.

  As can be understood from the above description, when the target partial print is printed in two partial prints, the partial print for printing the upstream portion of the target partial image and the partial image for printing the downstream portion of the target partial image , The paper M is not conveyed.

  In S162, the CPU 210 controls the transport unit 140 to transport the sheet M by a predetermined amount (specifically, by the nozzle length D). For example, an arrow AR3 along the Y direction in FIG. 13 corresponds to the conveyance of the sheet M in this step.

  In S165, CPU 210 determines whether or not all the partial images have been printed. In other words, it is determined whether the printing of the print image OI has been completed. If all the partial images have been printed (S165: YES), the CPU 210 ends the image processing. If there is an unprinted partial image (S165: NO), the CPU 210 returns to S120.

  In S130 of FIG. 6, when it is determined that the specific condition is not satisfied for the target partial image (S130: NO), the target partial image is printed by one partial printing. Specifically, in S170 of FIG. 7, similarly to S145 of FIG. 6, the CPU 210 executes the specific condition determination process on the next partial image. In the example of FIG. 14, the partial image PI2b does not satisfy the specific condition. If the partial image PI2b is the target partial image, in this step, it is determined whether or not the next partial image PI3b (FIG. 14) satisfies the specific condition, and the next partial image PI3b determines whether the specific condition is satisfied. If so, the division position DPn of the next partial image is determined. In the example of FIG. 14, it is assumed that the partial image PI3b is determined to satisfy the specific condition, and the division position DPn is determined.

  If it is determined that the specific condition is satisfied for the next partial image (S175: YES), in S180, CPU 210 determines whether the downstream portion of the next partial image can be printed together with the target partial image. I do. In the partial image of interest, the area from the position one block left to the right end of the left end LP of the downstream part of the next partial image (for example, the partial image PI3b in FIG. 13) is defined as an area IAb. If the object to be printed of the target partial image (for example, the object OBb of the partial image PI2b in FIG. 14) does not exist in the area IAb, it is determined that the downstream part of the next partial image can be printed together with the target partial image. Is done. In the example of FIG. 14, since the object OBb does not exist in the area IAb, it is determined that the downstream portion of the next partial image PI3b can be printed together with the partial image PI2b.

  When it is determined that the downstream portion of the next partial image can be printed together with the target partial image (S180: YES), in S195, the CPU 210 acquires dot data of the next partial image. In S200, the CPU 210 performs a mask process using the dot data of the next partial image. For example, thereby, a plurality of pixels in the intermediate portion MPn of the next partial image are assigned to one of two partial printings.

  In S205, the CPU 210 causes the printing mechanism 100 to print the target partial image and the downstream portion of the next partial image. For example, as indicated by an arrow AR4 in FIG. 14, the CPU 210 causes the partial image PI2b, which is the target partial image, to be printed in the forward direction, and when the printing of the partial image PI2b (printing of the object OBb) is completed, the CPU 210 proceeds. Is temporarily stopped. Then, as indicated by an arrow AR5 in FIG. 14, the CPU 210 conveys the sheet M by the nozzle length D. Then, as indicated by an arrow AR6 in FIG. 14, the CPU 210 restarts the main scanning in the forward direction, and determines the downstream portion of the next partial image PI3b (the pixel of the intermediate portion MPn assigned to the pixel The two parts SPn) are printed in the outward direction. As described above, the CPU 210 does not execute the main scan in the backward direction between the printing of the partial image of interest and the printing of the downstream part of the next partial image. As a result, it is possible to suppress the printing speed from being excessively reduced.

  Here, the section for one block is provided between the left end LP of the downstream portion of the next partial image and the left end of the area IAb because the downstream portion of the next partial image is transported after the paper M is conveyed. This is because a certain distance is needed to accelerate the print head 110 to a speed suitable for printing when the main scanning is restarted to print the image. As a modified example, the paper M may be conveyed between the printing of the target partial image and the printing of the downstream portion of the next partial image without stopping main scanning. In this case, while the paper M is being transported, printing cannot be performed even though the print head 110 is moving. A section having a predetermined length in the X direction is provided between the left end LP of the downstream portion of the image and the left end of the area IAb.

  In S210, the CPU 210 causes the printing mechanism 100 to print the upstream portion of the next partial image. The upstream portion of the next partial image is printed in a printing direction opposite to the printing direction of the downstream portion of the next partial image. For example, as indicated by an arrow AR7 in FIG. 14, the CPU 210 prints the upstream portion (the pixel of the intermediate portion MPn assigned by the mask process and the first portion FPn) of the next partial image PI3b in the backward direction. Let it. After S210, the process proceeds to S162 in FIG.

  When it is determined that the specific condition is not satisfied for the next partial image (S175: NO), and when it is determined that the downstream portion of the next partial image cannot be printed together with the target partial image (S180: NO). ), CPU 210 proceeds to S190. In S190, the CPU 210 causes the printing mechanism 100 to print the target partial image in one ordinary partial print. For example, when the preceding partial printing is the backward printing, the target partial image is printed in one forward printing. After S190, the process proceeds to S162 in FIG.

  In S150 of FIG. 6, when it is determined that the specific condition is not satisfied for the next partial image (S150: NO), the next partial image is printed by one partial printing. In this case, in S215 of FIG. 8, the CPU 210 determines whether the entirety of the next partial image can be printed together with the downstream portion of the target partial image. The downstream portion of the target partial image includes, for example, in the example of the partial image PI2c in FIG. 15, the second portion SP and the pixels of the intermediate portion MP that are allocated to the subsequent partial printing. In the next partial image (for example, the partial image PI3c in FIG. 15), an area from a position one block left to the right end of the left end LP of the downstream part of the target partial image (for example, the partial image PI2c in FIG. 15). The IAc is an area that cannot be printed together with the downstream portion of the target partial image. If the object to be printed of the next partial image (for example, the object OBc of the partial image PI3c in FIG. 15) is not included in the area IAc, the entirety of the next partial image is printed together with the downstream part of the target partial image. It is determined that it can be done. In the example of FIG. 15, since the object OBc does not exist in the area IAc, it is determined that the entirety of the next partial image PI3c can be printed together with the downstream part of the partial image PI2c.

  If it is determined that the whole of the next partial image can be printed together with the downstream portion of the target partial image (S215: YES), in S225, the CPU 210 acquires dot data of the next partial image.

  In S230, the CPU 210 causes the printing mechanism 100 to print the downstream portion of the target partial image and the entirety of the next partial image. For example, as indicated by an arrow AR7 in FIG. 15, the CPU 210 causes the downstream portion of the partial image PI2c, which is the target partial image, to be printed in the backward direction, and when the printing of the downstream portion of the partial image PI2c is completed, the backward direction is completed. Is temporarily stopped. Then, as indicated by an arrow AR8 in FIG. 15, the CPU 210 conveys the paper M by the nozzle length D. Then, as indicated by an arrow AR9 in FIG. 15, the CPU 210 restarts the main scanning in the backward direction and prints the entirety of the next partial image PI3c (object OBc) in the backward direction. In this way, the CPU 210 does not execute the main scanning in the forward direction between the printing of the downstream portion of the target partial image and the printing of the next partial image. As a result, it is possible to suppress the printing speed from being excessively reduced. After S230, the process proceeds to S162 in FIG.

  If it is determined that the entirety of the next partial image cannot be printed together with the downstream portion of the target partial image (S215: NO), only the downstream portion of the target partial image is printed in S220. For example, in the example of FIG. 16, some of the objects OBd1 and OBd2 to be printed of the next partial image PI3d are located in the area IAd. It is determined that the entire partial image PI3d cannot be printed. In this example, as indicated by an arrow AR10 in FIG. 16, the CPU 210 causes only the downstream portion of the partial image PI2d to be printed by the backward printing. After S220, the process proceeds to S162 in FIG. In the example of FIG. 16, after that, the paper M is conveyed as shown by an arrow AR11 in FIG. 16 (S162 in FIG. 6), and as shown by an arrow AR12 in FIG. Is printed by one forward pass printing (S190 in FIG. 7).

  If it is determined in S155 of FIG. 6 that the downstream portion of the target partial image and the upstream portion of the next partial image satisfying the specific condition can be printed (S155: YES), the process proceeds to S235 of FIG. Is advanced. The printing of the downstream portion of the target partial image and the upstream portion of the next partial image are performed. The downstream portion of the target partial image includes, for example, in the example of the partial image PI2e in FIG. 17, the second portion SP and the pixels assigned to the subsequent partial printing of the intermediate portion MP. In the example of the partial image PI3e in FIG. 17, the upstream portion of the next partial image includes the first portion FPn and the pixels of the intermediate portion MPn to be allocated to the previous partial printing. In the next partial image (for example, the partial image PI3e in FIG. 17), an area from the position left to the right end by one block from the left end LP of the downstream part of the target partial image (for example, the partial image PI2e in FIG. 17). IAe is an area that cannot be printed together with the downstream portion of the target partial image. In this example, since the upstream portion (the first portion FPn and the intermediate portion MPn) of the next partial image is not included in the area IAe, the upstream portion of the next partial image can be printed together with the downstream portion of the target partial image. Is determined.

  In S235 of FIG. 9, the CPU 210 acquires dot data of the next partial image. In S240, CPU 210 performs a mask process using the dot data of the next partial image. For example, thereby, a plurality of pixels in the intermediate portion MPn of the next partial image are assigned to one of two partial printings.

  In S245, the CPU 210 causes the printing mechanism 100 to print a downstream portion of the partial image of interest and an upstream portion of the next partial image. For example, as indicated by an arrow AR13 in FIG. 17, the CPU 210 prints the downstream portion (the pixel of the intermediate portion MP assigned by the mask process and the second portion SP) of the partial image PI2e by the backward printing. When the printing of the downstream portion is completed, the main scanning in the backward direction is temporarily stopped. Then, as indicated by an arrow AR14 in FIG. 17, the CPU 210 conveys the paper M by the nozzle length D. Then, as indicated by an arrow AR15 in FIG. 17, the CPU 210 restarts the main scanning in the backward direction, and determines the upstream portion of the next partial image PI3e (the pixel of the intermediate portion MPn that has been One part FPn) is printed in the backward direction. In this way, the CPU 210 does not execute the main scanning in the forward direction between the printing of the downstream portion of the target partial image and the printing of the upstream portion of the next partial image. As a result, it is possible to suppress the printing speed from being excessively reduced.

  In S250, the CPU 210 causes the printing mechanism 100 to print the downstream portion of the next partial image. For example, as indicated by an arrow AR16 in FIG. 17, the CPU 210 prints the downstream portion (the pixel of the intermediate portion MPn assigned by the mask process and the second portion SPn) of the partial image PI3e by forward printing. Let it. After S250, the process proceeds to S162 in FIG.

  According to the present embodiment described above, when the specific condition determined for each band-shaped partial image extending from one end to the other end in the main scanning direction of the print image OI is not satisfied for the target partial image (S130 in FIG. 6). NO), the CPU 210 causes the target partial image to be printed by one partial printing (S190, S205 in FIG. 7). If the specific condition is satisfied (YES in S130 of FIG. 6), the other end (for example, the right end of FIG. 13) including one end (for example, the left end in FIG. 13) of the target partial image in the main scanning direction is included. The first portion FP that is not included is printed by the preceding partial printing, and includes the other end (for example, the right end in FIG. 13) of the target partial image in the main scanning direction and does not include one end (for example, the left end in FIG. 13). The second part SP is printed by the subsequent partial printing.

  As described above, in the second case in which the specific condition indicating that the supply of the ink from the ink supply unit 150 to the print head 110 may be delayed in the focused partial printing is satisfied, the focused partial image is converted into two partial prints Printed. As a result, when a specific condition is satisfied, a delay in ink supply can be suppressed.

  Further, according to the present embodiment, one of the two partial prints for printing the target partial print when the specific condition is satisfied is a partial print performed in the main scan in the forward direction, and the other is a partial print in the backward direction. (Partial printing) performed in the main scanning of FIG. As a result, the printing speed can be increased as compared with the case where two partial printings are performed in the main scanning in the same direction. Therefore, even if the specific condition is satisfied, it is possible to suppress the printing speed from being excessively reduced.

  Furthermore, according to the present embodiment, the intermediate part MP (FIGS. 12 and 13 and the like) located between the first part FP and the second part SP in the target partial image is obtained when the specific condition is satisfied. Is printed in both of the two partial printings. As a result, for example, in a case where the position of the dot formed by one partial printing is shifted from the position of the dot formed by the other partial printing (also referred to as a dot positional shift). Even if there is, the problem that the boundary between the first part FP and the second part SP is conspicuous can be suppressed.

  Further, according to the present embodiment, the number of dots Dp, which is an index value of the amount of ink used in the target block, is calculated (S310 in FIG. 11), and the total number of dots Dt of the blocks processed up to that point is calculated. (S320 in FIG. 11). That is, the ink used when printing a portion from one end (for example, the left end in FIG. 12) of the target partial image to a specific position (for example, the right end of the target block) in the main scanning direction using the target dot data. The total number of dots Dt is calculated as an index value relating to the usage amount of. Then, when it is determined that the used amount of ink is equal to or more than the reference based on the comparison between the total number of dots Dt and the threshold (reference number Tv) (YES in S330 of FIG. 11), the specific condition is satisfied. It is determined (S340 in FIG. 11). As a result, whether or not the specific condition is satisfied can be efficiently determined using a part of the dot data.

  Further, according to the present embodiment, when it is determined that the specific condition is satisfied, the specific position (the right end of the target block) in the target partial image is shifted to one end side (the left side in FIG. 12). The DP is determined (S350 in FIG. 11, FIG. 12). As a result, the first portion FP is determined on one end side (left side in FIG. 12) of the specific position (right end of the block of interest). Therefore, based on the number Dt of dots, the first portion FP, and thus the second portion SP, can be appropriately determined. For this reason, a delay in ink supply can be appropriately suppressed.

  Further, according to the present embodiment, when the specific condition is satisfied, in the target partial image, the end opposite to one end of the first part FP (the right end in FIG. 12) and the other end of the second part SP Is determined at the opposite end (the left end in FIG. 12) and at the position of the boundary BD of the block BL. That is, these ends are determined at positions corresponding to one of the plurality of peaks PP of the sheet M. As a result, the problem that the boundary between the first part FP and the second part SP is conspicuous can be suppressed. The peak PP of the paper M is supported by the high support member 142 from the side opposite to the side where the print head 110 is located (FIG. 4C). For this reason, the position in the Z direction of the peak PP of the sheet M being conveyed is held with higher accuracy than the portion not supported by the support members 142 and 143. Therefore, during printing, the distance between the peak PP of the paper M and the nozzle forming surface 111 of the print head 110 is less likely to change than the distance between the other portion of the paper M and the nozzle forming surface 111. For this reason, in the peak portion PP of the paper M, since the above-described displacement of the dot position is unlikely to occur, it is possible to suppress the problem that the boundary between the first portion FP and the second portion SP is conspicuous.

  As a modified example, the position of the boundary BD of the block BL, the right end of the first portion FP, and the left end of the second portion SP are respectively located on the plurality of valleys VP of the sheet M (FIG. 4C). The position may be determined to correspond to any one of them. The valley VP of the paper M is supported by the low support member 143 from the side opposite to the side where the print head 110 is located (FIG. 4C). This is because it is held with higher accuracy than the part not supported by 143.

  Further, according to the present embodiment, the specific condition is satisfied for the partial image PI2e (FIG. 17), and the specific condition is satisfied for the partial image PI3e (FIG. 17) adjacent to the partial image PI2e in the sub-scanning direction. In this case, the partial printing for printing the first part FPn of the partial image PI3e (arrow AR15 in FIG. 17) and the partial printing for printing the second part SP of the partial image PI2e (arrow AR13 in FIG. 17) are the same. This can be executed by the main scanning in the backward direction (S245 in FIG. 9). Then, the main scanning in the forward direction is not executed between these two partial printings. Therefore, the main scan in the forward direction is not executed between the printing of the second part SP of the partial image PI2e and the printing of the first part FPn of the partial image PI3e, both of which are performed in the main scanning in the backward direction. Even if the condition is satisfied, it is possible to suppress the printing speed from excessively decreasing.

  Further, according to the present embodiment, a stop period for stopping the movement (main scanning) of the print head between the printing of the second part SP of the partial image PI2e and the printing of the first part FPn of the partial image PI3e. Is provided. Therefore, it is possible to secure a time for carrying the sheet M (for example, the arrow AR14 in FIG. 17).

  Further, according to the present embodiment, the specific condition is satisfied for the partial image PI3b (FIG. 14), and the specific condition is satisfied for the partial image PI2b (FIG. 14) adjacent to the partial image PI3b in the sub-scanning direction. When there is no object to be printed in the specific area IAb including one end (the right end in FIG. 14) of the partial image PI2b and the second part SPn of the partial image PI3b is printed (arrow AR5 in FIG. 14). And one partial printing of the partial image PI2b (arrow AR4 in FIG. 14) is executed in the outward direction. Then, the main scanning in the backward direction is not executed between these two partial printings. Accordingly, since the main scanning in the backward direction is not performed between the printing of the second part SPn of the partial image PI3b and the printing of the partial image PI2b, both of which are performed in the main scanning in the forward direction, the specific condition is satisfied. Even in this case, it is possible to suppress the printing speed from excessively decreasing.

  Further, according to the present embodiment, a stop period for stopping the movement (main scanning) of the print head is provided between the printing of the second part SPn of the partial image PI3b and the printing of the partial image PI2b. Accordingly, it is possible to secure time for executing the conveyance of the sheet M (for example, the arrow AR5 in FIG. 14).

  Furthermore, in the above embodiment, since the CPU 210 of the printer 200 executes the image processing of FIGS. 6 to 9, it depends on, for example, the processing of the terminal device 300 (for example, the processing of the driver installed in the terminal device 300). Instead, the delay in ink supply can be suppressed only by the printer 200.

B. Modified Example (1) In the above embodiment, when the target partial image is printed in two partial prints in order to satisfy a specific condition, one of the two partial prints is forward print and the other is return print. It is. Instead, both of the two partial printings may be forward printing. This case will be described assuming that the partial image PI2 in FIG. 12 is the target partial image. By the first forward pass printing, dots corresponding to the first portion FP and a part of the intermediate portion MP are formed, and the print head 110 is stopped near the division position DP. Then, after a predetermined stop period, the main scanning in the backward direction is performed, and the print head 110 is returned to a position on the right side of the right end of the intermediate portion MP by a predetermined amount. Thereafter, the main scanning in the forward direction is performed again, and dots corresponding to the second portion SP and a part of the intermediate portion MP are formed.

(2) In the above embodiment, when the specific condition is satisfied, the target partial image is printed by two partial printings. Alternatively, if a specific condition is satisfied, the target partial image may be printed by partial printing three or more times. For example, when the index value of the ink amount used for printing the target partial image indicates an ink amount that is equal to or more than the first reference and less than the second reference, the target partial image is printed in two partial printings, and the index value Indicates the ink amount equal to or larger than the third reference, the target partial image may be printed in three partial prints. When the target partial image is printed by three partial printings, for example, the target partial image is divided into three parts (for example, a right end part, a left end part, and a center part), and the three parts are printed. Each part is printed by different partial printing.

(3) In the above embodiment, when the target partial image satisfies the specific condition, the division position DP of the target partial image is determined based on the number of dots Dp calculated for each block (S350 in FIG. 11). Instead, the division position DP may be determined by another method.

  FIG. 18 is an explanatory diagram of the determination of the division position according to the modification. In this example, the division position is determined in consideration of the partial image to be printed immediately before. A description will be given assuming that the partial image PI3f in FIG. 18 is a target partial image. The partial image PI3f satisfies the specific condition, and the partial image PI2f printed immediately before does not satisfy the specific condition. It is assumed that the partial image PI2f is printed in the outward direction (+ X direction). In this case, the CPU 210 specifies the print end position EP based on the position of the object OBf of the previous partial image PI2f. Then, the CPU 210 determines a position on the downstream side in the outward direction by the predetermined length SL from the printing end position EP as the division position DPv of the partial image PI3f. The predetermined length SL is determined based on, for example, a distance required to accelerate the print head 110 when the print head 110 that has stopped once is moved again. The CPU 210 determines the first part FP, the second part SP, and the middle part MP of the partial image PI3f based on the division position DPv.

  In this case, printing of the partial image PI2f and the partial image PI3f is performed as follows. As indicated by an arrow ARa in FIG. 18, the CPU 210 causes the partial image PI2f to be printed in the forward direction, and when the printing of the partial image PI2f is completed, the main scanning in the forward direction is temporarily stopped at the print end position EP. Then, as indicated by an arrow ARb in FIG. 18, the CPU 210 conveys the sheet M by the nozzle length D. Then, as indicated by an arrow ARc in FIG. 18, the CPU 210 restarts the main scanning in the forward direction, and prints the downstream portion (a part of the intermediate portion MP and the second portion SP) of the partial image PI3f in the forward direction. . Further, as indicated by an arrow ARd in FIG. 18, the CPU 210 causes the upstream portion (part of the intermediate portion MP and the first portion FP) of the partial image PI3f to be printed in the backward direction.

  Note that, for example, when the object OBf is arranged on the entire partial image PI2f, the division position DPv may not be determined by the above method. In this case, the division position DPv is determined to be, for example, a predetermined position (for example, a center position in the main scanning direction). Then, after the partial image PI2f is printed in the forward direction, the downstream portion of the partial image PI3f is printed in the backward direction. Further, thereafter, the upstream portion of the partial image PI3f is printed in the outward direction.

  FIG. 19 is an explanatory diagram of the determination of the division position according to the modification. In this example, the division position is determined in consideration of a partial image to be printed immediately thereafter. A description will be given assuming that the partial image PI2g in FIG. 19 is a target partial image. The partial image PI2g satisfies the specific condition, and the partial image PI3g printed immediately after does not satisfy the specific condition. The partial image PI2g is printed by the partial printing in the forward direction performed first and the partial printing in the backward direction performed later. In this case, the CPU 210 specifies the print start position PSP based on the position of the object OBg of the subsequent partial image PI2g. Then, the CPU 210 determines a position on the upstream side in the backward direction by the predetermined length SL from the second portion SP as the division position DPv of the partial image PI2g. The CPU 210 determines the first part FP, the second part SP, and the intermediate part MP of the partial image PI2g based on the division position DPv.

  In this case, printing of the partial image PI2g and the partial image PI3g is performed as follows. As indicated by an arrow ARd in FIG. 19, the CPU 210 causes the upstream portion (a portion of the intermediate portion MP and the first portion FP) of the partial image PI2g to be printed in the outward direction. Thereafter, as indicated by an arrow ARe in FIG. 19, the CPU 210 causes the downstream portion (the part of the intermediate portion MP and the second portion SP) of the partial image PI2g to be printed in the backward direction, and is located upstream of the print start position PSP. To temporarily stop the main scanning in the backward direction. Then, as indicated by an arrow ARf in FIG. 19, the CPU 210 conveys the sheet M by the nozzle length D. Then, as indicated by an arrow ARd in FIG. 19, the CPU 210 restarts the main scanning in the backward direction and prints the partial image PI3g in the backward direction.

  Note that, for example, when the object OBg is arranged in the entire partial image PI3g, the division position DPv may not be determined by the above method. In this case, the division position DPv is determined to be, for example, a predetermined position (for example, a center position in the main scanning direction).

(4) In the above embodiment, the intermediate part MP is provided between the first part FP and the second part SP when the target partial image is printed by two partial printings, but the intermediate part MP is provided. You don't have to. In this case, the CPU 210 causes one of the two partial printings to print the first part FP and the other to print the second part SP.

(5) The configuration of the transport unit 140 in the above embodiment is an example. For example, the transport unit 140 transports the paper M while holding the paper M in a deformed state in a wave shape. Alternatively, the transport unit 140 may transport the paper M in a flat state without deforming the paper M in a wave shape.

(6) The image processing in the above embodiment is an example, and can be appropriately changed. For example, the image processing may be a simpler processing. For example, in the image processing, when printing a target partial image, all processes for considering the next partial image may be omitted. In this case, for example, S145 to S155 in FIG. 6 and the processing in FIGS. 7 to 9 are omitted. Then, in S130 of FIG. 6, when it is determined that the target partial image does not satisfy the specific condition (S130: NO), the target partial image is printed by one partial printing similarly to S190 of FIG. Printed. Then, the process proceeds to S162 in FIG.

(7) In each of the above embodiments, the condition indicating whether or not a delay in ink supply can occur is determined using the head temperature Th, the accumulated ink usage amount TA, and the number of dots Dp. Not limited to For example, the determination may be made using only the head temperature Th and the number of dots Dp. In this case, for example, in the threshold table TT of FIG. 10, only three determination thresholds JT corresponding to three types of head temperatures Th (low, medium, and high) need be specified. Alternatively, the determination may be made using only the cumulative ink usage amount TA and the number of dots Dp. In this case, the threshold table TT need only specify three determination thresholds JT corresponding to the three types of cumulative ink usage amounts TA (small, medium, and large).

(8) Instead of the number of dots Dp, another index value regarding the amount of ink used may be adopted. For example, when the CMYK image data in the target block can be acquired, another index value may be an integrated value of component values corresponding to each ink of the CMYK image data. The CMYK image data is image data indicating the color of each pixel by CMYK values. The CMYK values include component values indicating the density of each of the C, M, Y, and K inks as 256 tone values. Further, instead of the cumulative ink usage TA, another index value regarding the cumulative ink usage may be adopted. For example, another index value may be the cumulative number of printed sheets or the cumulative number of ink cartridge replacements. It can be said that the larger the accumulated number of printed sheets and the number of times of replacement are, the larger the accumulated ink usage amount TA is. Therefore, it can be said that the accumulated number of printed sheets is an index value relating to the accumulated ink usage amount TA.

(9) In the printing mechanism 100 of the above-described embodiment, the sub-scanning in which the paper M is moved relative to the print head 110 in the transport direction is performed by the transport unit 140 transporting the paper M. Alternatively, the sub-scanning may be performed by moving the print head 110 with respect to the fixed sheet M in a direction opposite to the transport direction.

(10) As the print medium, instead of the paper M, another medium, for example, an OHP film, a CD-ROM, or a DVD-ROM may be adopted.

(11) In each of the above embodiments, the apparatus that executes the image processing of FIGS. 6 to 9 is the CPU 210 of the printer 200. Instead, the device that executes the image processing may be another type of device, for example, the terminal device 300. In this case, for example, the terminal device 300 operates as a printer driver by executing a driver program, controls the printer 200 as a print execution unit as a part of the function as the printer driver, and performs image processing. Let it run. In this case, the terminal device 300 realizes, for example, transport of the paper M by transmitting a transport command including information indicating the transport amount of the paper M to the printer 200. In this case, the terminal device 300 acquires the head temperature Th and the accumulated ink usage amount TA from the printer 200 in S105 and S110 in FIG. In addition, the terminal device 300 realizes partial printing by transmitting, for example, a partial print command including print data to the printer 200.

  As can be understood from the above description, in the above embodiment, the printing mechanism 100 is an example of a print execution unit, and when the terminal device 300 executes image processing as in this modification, the printer 200 that executes printing is used. Is an example of the print execution unit.

(12) The apparatus that executes the image processing shown in FIGS. 6 to 9 acquires image data from, for example, the printer 200 or the terminal device 300 and generates the above-described transport command or partial print command using the image data. The server may transmit these commands to the printer 200. Such a server may be a plurality of computers that can communicate with each other via a network.

(13) In each of the above embodiments, a part of the configuration realized by hardware may be replaced by software, and conversely, a part or all of the configuration realized by software is replaced by hardware. You may do so. For example, some of the image processing in FIGS. 6 to 9 may be realized by a dedicated hardware circuit (for example, an ASIC) that operates according to an instruction from the CPU 210.

  As described above, the present invention has been described based on the examples and the modified examples. However, the above-described embodiments are for facilitating understanding of the present invention, and do not limit the present invention. The present invention can be modified and improved without departing from the spirit and scope of the claims, and the present invention includes equivalents thereof.

  100 printing mechanism, 110 printing head, 111 nozzle forming surface, 120 head driving unit, 130 main scanning unit, 133 carriage, 134 sliding door, 135 belt, 136 pulley, 140 transport unit .., 141... A paper stand, 142... A high support member, 143. A low support member, 144. A flat plate, 146. .., Drive roller, 148b, driven roller, 150, ink supply section, 151, cartridge mounting section, 152, tube, 153, buffer tank, 170, temperature sensor, 200, printer, 210, CPU, 220, non-volatile storage device, 230 volatile storage device, 231 buffer area, 260 operation unit, 270 display unit, 280 communication Department, 300 ... terminal apparatus, 331 ... buffer area, M ... sheet, D ... nozzle length, PG ... computer program, OI ... print image, BL ... block, TT ... threshold table, NW ... Network

Claims (11)

A print head having a plurality of nozzles for discharging ink, an ink supply unit for supplying the ink to the print head, and a main scan for moving the print head along a main scan direction with respect to a print medium. Image processing for a print execution unit, comprising: a main scanning unit; and a sub-scanning unit that performs sub-scanning for moving the print medium in a sub-scanning direction that intersects the main scanning direction with respect to the print head. A device,
An acquisition unit for acquiring image data;
Using the image data, partial printing in which the print head ejects the ink while the main scanning section performs the main scanning, and causing the sub-scanning section to perform the sub-scanning are performed a plurality of times. A print control unit that causes the print execution unit to perform printing,
With
The print control unit includes:
Specific conditions determined for each strip-shaped partial image extending from one end to the other end of the print image in the main scanning direction, and the supply of the ink from the ink supply unit to the print head may be delayed in the partial printing. In the first case where the specific condition indicating that the partial image is not satisfied, the partial image is printed by one partial printing,
In a second case where the specific condition is satisfied, a first portion of the partial image including the one end in the main scanning direction and not including the other end is printed by the first partial printing, and An image processing apparatus that causes a second portion of the partial image that includes the other end in the main scanning direction and does not include the one end to be printed by the second partial printing. The image processing device according to claim 1,
The first partial printing is the partial printing performed in the main scanning in a first direction along the main scanning direction,
The second partial printing is the partial printing performed in the main scanning in the second direction, which is a second direction along the main scanning direction and opposite to the first direction. Processing equipment. The image processing device according to claim 1 or 2,
The partial image includes a third part located between the first part and the second part,
The image processing apparatus, wherein in the second case, the print control unit causes the third part to be printed by both the first partial print and the second partial print. The image processing device according to claim 1,
Using the partial image data corresponding to the partial image, calculate an index value related to the amount of ink used when printing a part of the partial image from the one end to the specific position in the main scanning direction. Equipped with a calculation unit,
When it is determined that the used amount of the ink is equal to or more than a reference based on the comparison between the index value and the threshold, it is determined that the specific condition is satisfied,
The image processing apparatus may further include, when it is determined that the used amount of the ink is equal to or more than a reference based on a comparison between the index value and a threshold, the one end side of the partial image relative to the specific position. An image processing apparatus, further comprising: a part determining unit that determines the first part. The image processing apparatus according to claim 1, wherein
The sub-scanning unit includes a holding unit that holds the print medium in a state of being deformed in a wave shape at a position facing the print head,
The print medium deformed in a wavy shape includes a plurality of peaks extending along the sub-scanning direction and arranged in the main scanning direction,
The holding unit is a plurality of support units extending along the sub-scanning direction and arranged in the main scanning direction, and supports each of the plurality of peaks from a side opposite to a side where the print head is located. Comprising the plurality of support portions,
The image processing apparatus may further include, when the specific condition is satisfied, in the partial image, an end opposite to the one end of the first portion and an end opposite to the other end of the second portion. An image processing apparatus comprising: a position determining unit that determines at least one of an end and a position corresponding to one of the plurality of peaks of the print medium. The image processing apparatus according to claim 1,
The print control unit may satisfy the specific condition for the first partial image, and satisfy the specific condition for a second partial image adjacent to the first partial image in the sub-scanning direction. The first partial printing to print the first part of the first partial image, and the second partial printing to print the second part of the second partial image, The main scanning in the first direction along the main scanning direction,
The print control unit, the first partial print to print the first part of the first partial image, and the second partial print to print the second part of the second partial image, An image processing apparatus that does not execute the main scanning in the direction opposite to the first direction during the period. The image processing device according to claim 6,
The print control unit, the first partial print to print the first part of the first partial image, and the second partial print to print the second part of the second partial image, An image processing apparatus, wherein a stop period for stopping the movement of the print head is provided between them. The image processing apparatus according to claim 1,
The print control unit may satisfy the specific condition for the first partial image, and satisfy the specific condition for a second partial image adjacent to the first partial image in the sub-scanning direction. And if there is no object to be printed in a specific area including the other end of the second partial image, the second partial printing to print the second part of the first partial image; The one partial printing of printing the second partial image, and the main scanning in a first direction along the main scanning direction,
The print control unit, between the second partial print that prints the second part of the second partial image, and the one partial print that prints the second partial image, An image processing apparatus that does not execute the main scanning in the direction opposite to the first direction. The image processing device according to claim 8, wherein:
The print control unit, between the first partial print to print the first part of the first partial image and the one partial print to print the second partial image, An image processing apparatus having a stop period for stopping the movement of a print head.   A printing apparatus, comprising: the image processing apparatus according to claim 1; and the print execution unit. A print head having a plurality of nozzles for discharging ink, an ink supply unit for supplying the ink to the print head, and a main scan for moving the print head along a main scan direction with respect to a print medium. Computer program for a print execution unit, comprising: a main scanning unit; and a sub-scanning unit that executes a sub-scanning that moves the print medium in a sub-scanning direction that intersects the main scanning direction with respect to the print head. And
An acquisition function for acquiring image data,
Using the image data, partial printing in which the print head ejects the ink while the main scanning section performs the main scanning, and causing the sub-scanning section to perform the sub-scanning are performed a plurality of times. A print control function for causing the print execution unit to perform printing,
To the computer,
The print control function includes:
Specific conditions determined for each strip-shaped partial image extending from one end to the other end of the print image in the main scanning direction, and the supply of the ink from the ink supply unit to the print head may be delayed in the partial printing. In the first case where the specific condition indicating that the partial image is not satisfied, the partial image is printed by one partial printing,
In the second case in which the specific condition is satisfied, a first portion of the partial image including the one end in the main scanning direction and not including the other end is printed by the first partial printing, and A computer program for causing a second portion of the partial image that includes the other end in the main scanning direction and does not include the one end to be printed by the second partial printing.

Images