JP2020023074A - Image processing device and computer program - Google Patents

Abstract

To improve printing speed of printing using forward printing and backward printing.SOLUTION: A profile for forward printing and a profile for backward printing are adjusted so that a color of an image to be printed in a forward direction using the profile for a forward printing and a color of an image to be printed in a backward printing using the profile for a backward printing are similar to each other. An image processing device executes first generation processing which is executed using the profile corresponding to a first direction, the opposite direction of a printing direction of partial printing lastly performed, to generate first partial printing data; and executes second generation processing which is executed using the profile corresponding to a second direction, the same direction as the printing direction of the partial printing lastly performed, to generate second partial printing data. The image processing device determines a noticeable printing direction to be the first direction using noticeable partial image data, outputs first partial printing data when the noticeable printing direction is determined to be the first direction, and outputs second partial printing data when the noticeable printing direction is determined to be the second direction.SELECTED DRAWING: Figure 5

Description

  This specification relates to image processing for a print execution unit that performs printing by performing partial printing for forming dots and sub-scanning a plurality of times while performing main scanning.

  Patent Document 1 discloses a multifunction machine that prints an image using an ejection process that ejects ink while moving a print head in a forward direction and an ejection process that ejects ink while moving a print head in a reverse direction. Image processing apparatus is disclosed. This image processing apparatus determines that the color difference between a band image printed by a forward ejection process and a band image printed by a reverse ejection process is relatively large according to the pixel value of the band image data. It is determined whether or not the condition shown is satisfied. If the condition is satisfied, the image processing apparatus determines the direction of the ejection process to be the forward direction. If the condition is not satisfied, the image processing device sets the direction of the ejection process to the direction opposite to the direction of the immediately preceding ejection process. To decide.

JP 2017-39205 A

  However, in the image processing apparatus, the direction of the ejection process is easily determined to be the forward direction depending on the image. In this case, there is a possibility that the printing speed is excessively reduced as compared with the case where the forward discharge process and the reverse discharge process are alternately repeated.

  This specification discloses a technique capable of improving the printing speed of printing using forward printing and backward printing.

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

[Application Example 1] A first type nozzle that discharges a first type of ink is different from a position of the first type nozzle in the main scanning direction, and a second type of nozzle that discharges a second type of ink. A main scanning unit that performs a main scan that moves the print head along the main scanning direction with respect to a print medium, and a sub-scan that intersects the main scanning direction with respect to the print head. A sub-scanning unit that performs a sub-scan that moves the print medium along a direction, and a partial execution that forms dots on the print medium by the print head while performing the main scan. Performing the printing by performing the sub-scanning a plurality of times, the image processing apparatus for the print execution unit, for the outward path for the partial printing in the outward direction along the main scanning direction Color conversion profile and the main A return path color conversion profile for the partial printing in the return direction along the inspection direction, and a storage unit in which the forward path color conversion profile and the return path color conversion profile are stored. A profile for converting a first type of color value into a second type of color value including component values corresponding to a plurality of types of ink including the first type of ink and the second type of ink. The color of the image printed in the partial printing in the forward direction based on the second type of color value obtained by converting the first type of color value using the color conversion profile for the forward path And printing in the partial printing in the return direction based on the second type color value obtained by converting the specific first type color value using the return path color conversion profile. The color of the image is adjusted to be closer, Storing unit, and executing a first generation process including a first color conversion process on target partial image data corresponding to the target partial image to be printed in the partial print to be processed, to generate first partial print data. A first generation unit that generates the first color conversion process, wherein, of the color conversion profile for the forward path and the color conversion profile for the return path, A first generation unit that executes using a profile corresponding to a first direction that is a reverse direction, and performs a second generation process including a second color conversion process on the target partial image data A second generation unit for generating second partial print data, wherein the second color conversion processing is performed by using the immediately preceding color conversion profile among the color conversion profile for the forward path and the color conversion profile for the return path. In the second direction, which is the printing direction of partial printing The second generator, which is executed using a corresponding profile;
A print direction determining unit that determines the target print direction, which is the print direction of the partial print to be processed, using the target partial image data, to one of the forward direction and the return direction; It is determined that a difference in color between the target partial image printed using the first partial print data and the target partial image printed using the second partial print data is less than a reference. The printing direction is determined to be the first direction, and if it is determined that the color difference is greater than or equal to the reference, the printing direction is determined to be the second direction. A determination unit, and, when the target print direction is determined to be the first direction, outputting the first partial print data to the print execution unit to cause the partial print of the processing target to be performed in the first direction And the noted printing direction is An output unit that, when determined in the second direction, outputs the second partial print data to the print execution unit to cause the partial print of the processing target to be performed in the first direction. Processing equipment.

  According to the above configuration, an image printed by partial printing in the forward direction based on the second type of color value obtained by converting a specific first type of color value using the color conversion profile for the forward direction. And a color of an image printed by partial printing in the backward direction based on a second type of color value obtained by converting a specific first type of color value using the color conversion profile for the backward direction. Are used for the forward path and the return path. As a result, there is a possibility that the difference in color between the target partial image printed using the first partial print data and the target partial image printed using the second partial print data is less than the reference. Get higher. As a result, there is a high possibility that the target printing direction is determined to be opposite to the printing direction of the immediately preceding partial printing. As a result, the printing speed of printing using forward printing and backward printing can be improved.

  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. 1 is a block diagram illustrating a configuration of a printing system 1000 according to an embodiment. FIG. 2 is a diagram illustrating a schematic configuration of a printing mechanism. FIG. 4 is an explanatory diagram of the operation of the printing mechanism 100. FIG. 9 is an explanatory diagram of color evaluation information CI. 5 is a flowchart of image processing A according to the first embodiment. FIG. 3 is a diagram illustrating a part of a print image OI. 9 is a flowchart of image processing B according to the second embodiment. 13 is a flowchart of image processing C according to the third embodiment. It is a flow chart of image processing D of a 4th example. It is a flow chart of processing of a 5th example.

A. First embodiment:
A-1: Configuration of Printing System 1000 Next, an embodiment will be described based on an example. FIG. 1 is a block diagram illustrating a configuration of a printing system 1000 according to the embodiment.

  The printing system 1000 includes a printer 200 and a terminal device 300 as an image processing device of the present embodiment. The printer 200 and the terminal device 300 are communicably connected via a wired or wireless network NW.

  The terminal device 300 is a computer used by the user of the printer 200, and is, for example, a personal computer or a smartphone. The terminal device 300 includes a CPU 310 as a controller of the terminal device 300, a nonvolatile storage device 320 such as a hard disk drive, a volatile storage device 330 such as a RAM, an operation unit 360 such as a mouse and a keyboard, and a liquid crystal display. A display unit 370 and a communication unit 380 are provided. Communication unit 380 includes a wired or wireless interface for connecting to network NW.

  The volatile storage device 330 provides a buffer area 331 for the CPU 310. The non-volatile storage device 320 stores a computer program PG1, a forward path profile PF1, a return path profile PF2, and color evaluation information CI. The computer program PG1, the outbound path profile PF1, the inbound path profile PF2, and the color evaluation information CI are provided by the manufacturer of the printer 200, for example, in a form downloaded from a server or stored in a DVD-ROM or the like. You. The CPU 310 functions as a printer driver that controls the printer 200 by executing the computer program PG2. The CPU 310 as a printer driver executes, for example, image processing described later, and causes the printer 200 to print an image.

  The forward path profile PF1 and the return path profile PF2 are profiles that define the correspondence between the color values of the RGB color system (RGB values) and the color values of the CMYK color system (CMYK values). The forward path profile PF1 and the backward path profile PF2 are used for color conversion processing for converting RGB values into CMYK values in image processing described later. The RGB values are color values including three component values of red (R), green (G), and blue (B). The CMYK values include a plurality of component values corresponding to a plurality of types of inks used for printing, and in the present embodiment, include Cyan (C), Magenta (M), Yellow (Y), and Black (K) component values. Color value. The RGB value and the CMYK value are, for example, 256 gradation values. The outward profile PF1 and the backward profile PF2 are, for example, lookup tables. The difference between the forward path profile PF1 and the return path profile PF2 and the color evaluation information CI will be described later.

  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 PG2. In this embodiment, the computer program PG2 is a control program for controlling the printer 200, and may be provided by being stored in the nonvolatile storage device 220 when the printer 200 is shipped. Instead, the computer program PG2 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. By executing the computer program PG2, the CPU 210 controls the printing mechanism 100 in accordance with, for example, print data and direction information (described later) transmitted from the terminal device 300 by image processing to be described later, and on a print medium (for example, paper). Print the image on

  The printing mechanism 100 performs printing by discharging each ink (droplet) of C, M, Y, and K. The printing mechanism 100 includes a print head 110, a head driving unit 120, a main scanning unit 130, and a transport unit 140.

  FIG. 2 is a diagram illustrating a schematic configuration of the printing mechanism 100. As shown in FIG. 2A, the main scanning unit 130 includes a carriage 133 on which the print head 110 is mounted, and a slide that holds the carriage 133 so as to be able to reciprocate along the main scanning direction (the X-axis direction in FIG. 2). A driving shaft 134. The main scanning unit 130 reciprocates the carriage 133 along the sliding shaft 134 using the power of a main scanning motor (not shown). 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 transport unit 140 transports the paper M in a transport direction (+ Y direction in FIG. 2) crossing the main scanning direction while holding the paper M. As shown in FIG. 2, a sheet tray 145, an upstream roller pair 142, and a downstream roller pair 141 are provided. Hereinafter, the upstream side (−Y side) in the transport direction is also simply referred to as the upstream side, and the downstream side (+ Y side) in the transport direction is also simply referred to as the downstream side.

  The upstream roller pair 142 holds the paper M on the upstream side (−Y side) of the print head 110, and the downstream roller pair 141 holds the paper M on the downstream side (+ Y side) of the print head 110. The paper table 145 is located between the upstream roller pair 142 and the downstream roller pair 141 and at a position facing the nozzle forming surface 111 of the print head 110. The paper M is transported by driving the downstream roller pair 141 and the upstream roller pair 142 by a transport motor (not shown).

  The head drive unit 120 (FIG. 1) supplies a drive signal to the print head 110 and drives the print head 110 while the main scanning unit 130 is performing main scan of the print head 110. The print head 110 forms dots by discharging ink on the paper conveyed by the conveyance unit 140 according to the drive signal.

  FIG. 2B illustrates the configuration of the print head 110 as viewed from the −Z side (the lower side in FIG. 2). As shown in FIG. 2B, the nozzle formation surface 111 of the print head 110 has a plurality of nozzle rows including a plurality of nozzles, that is, a nozzle row for ejecting each of the above-described C, M, Y, and K inks. NC, NM, NY, and NK are formed. 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.

A-2. Overview of Printing The printing mechanism 100 alternately performs partial printing in which dots are formed on the paper M by the print head 110 while performing main scanning by the main scanning unit 130 and sub-scanning (transportation of the paper M) by the transport unit 140. The print image OI is printed on the sheet M by executing the process a plurality of times.

  FIG. 3 is an explanatory diagram of the operation of the printing mechanism 100. FIG. 3 shows print images OI1 and OI2 to be printed on sheets M1 and M2, respectively. The print image includes a plurality of partial images PI. In the example of FIG. 3, the print images OI1 and OI2 include partial images PI1 to PI5 and PI6 to PI10, respectively. Each partial image PI is an image printed by one partial printing. The printing direction of the partial printing is one of the forward direction and the backward direction. In other words, the partial printing includes forward printing in which dots are formed while performing main scanning in the forward direction (+ X direction in FIG. 3), and returning printing in which dots are formed while performing main scanning in the backward direction (−X direction in FIG. 3). And printing. In FIG. 3, a solid line arrow in the + X direction or the −X direction is given in the partial image. The partial images PI1, PI2, PI3, PI5, PI7, PI8, and PI10 with solid line arrows in the + X direction are forward pass partial images printed by forward pass printing. The partial images PI4, PI6, and PI9 indicated by solid arrows in the −X direction are return path partial images printed by return path printing.

  In FIG. 3, an arrow in the −Y direction from one partial image PI (for example, the partial image PI1) to another partial image PI (for example, the partial image PI2) adjacent in the −Y direction indicates the conveyance of the sheet M. (Sub-scan). That is, the arrow in the −Y direction in FIG. 3 indicates that the print head 110 moves in the −Y direction with respect to the sheet M illustrated in FIG. As shown in FIG. 3, the printing of the present embodiment is so-called one-pass printing, and the length of each partial image in the transport direction and the transport amount of the sheet M at one time are the nozzle length D.

  Here, as shown in FIG. 2B, as shown in the print head 110, the positions of the CMYK nozzle rows NC, NM, NY, and NK in the main scanning direction are different from each other. For this reason, when forming each dot of CMYK at the same position on the paper M, the order of dot formation differs between forward printing and backward printing. For example, in the example of FIG. 2B, dots are formed in the order of K, C, M, and Y in the forward pass printing, and dots are formed in the order of Y, M, C, and K in the backward pass printing. Is done. As a result, in an area where dots of a plurality of colors overlap, the order of overlapping dots differs between the forward pass partial image and the return pass partial image. For this reason, the printed colors may be different between the forward pass partial image and the return pass partial image even if they are printed using the same dot data. Such a difference in the colors printed between the forward pass partial image and the return pass partial image (also referred to as a round-trip color difference) occurs.

  Here, the above-described outward path profile PF1 is used to convert RGB values into CMYK values when generating partial print data for outward path printing, that is, print data for one outward path print indicating an outward path partial image. Used for The return path profile PF2 is used to convert RGB values into CMYK values when generating partial print data for return path printing, that is, print data for one return path print indicating a return path partial image. The forward path profile PF1 and the backward path profile PF2 are color-matched with each other so as to reduce the above-mentioned color difference between reciprocation. More specifically, these profiles PF1 and PF2 include the color of the outward partial image printed based on the CMYK values obtained by converting a specific RGB value using the outward profile PF1, and the specific RGB. The value is adjusted so that the color of the return path partial image printed based on the CMYK value obtained by converting the value using the return path profile PF2 approaches.

  However, for a specific color, since the color difference between reciprocation is large, there is a case where the color difference between reciprocation cannot be sufficiently suppressed even by using the forward pass profile PF1 and the return pass profile PF2. The color evaluation information CI (FIG. 1) is information that defines weights according to the color difference between round trips for each of the RGB values.

  FIG. 4 is an explanatory diagram of the color evaluation information CI. FIG. 4A shows an RGB color space CC. Codes indicating colors (specifically, black vertex Vk (0, 0, 0), red vertex Vr (255, 0, 0), green vertex Vg (0, 255, 0), blue vertex Vb (0, 0, 255), cyan vertex Vc (0, 255, 255), magenta vertex Vm (255, 0, 255), yellow vertex Vy (255, 255, 0), white Vertex Vw (255, 255, 255)) is attached. The numbers in parentheses indicate the value of each color component of (R, G, B). The value of R of each grid GD is any of Q + 1 values obtained by dividing the range of R (here, from zero to 255) by Q. The same applies to the values of green G and blue B of each grid GD. In this embodiment, since Q = 9, 9 <3> (729) grids GD are set in the RGB color space CC.

  FIG. 4B shows an example of the color evaluation information CI. In the color evaluation information CI, a weight Wt is associated with each of the RGB values corresponding to the 729 grids GD. For example, the evaluator converts the RGB values of a specific grid GD into color patches printed based on the CMYK values obtained by converting the RGB values of the grid GD using the forward path profile PF1, and the RGB values of the grid GD into the return path profile. And a color patch to be printed based on CMYK values obtained by conversion using PF2. The evaluator obtains a colorimetric value by measuring the color of the two color patches. The colorimetric values are, for example, color values in a color space independent of devices such as the printing mechanism 100, and in the present embodiment, color values in a CIELAB color space (hereinafter also referred to as Lab values). The evaluator calculates the color difference between the two acquired colorimetric values as the round-trip color difference dM corresponding to the specific grid GD. The evaluator determines the larger weight Wt as the inter-round color difference dM is larger, as the weight Wt associated with the specific grid GD. Thus, the weight Wt associated with the 729 grids GD is determined, and the color evaluation information CI is created.

  As described above, the round-trip color difference is caused by a difference in the order in which dots overlap between the forward pass partial image and the return pass partial image. For this reason, the color difference between reciprocation increases in a specific color (also referred to as a color difference generation color) expressed using two types of inks among the C, M, Y, and K inks used for printing. The color difference generation color includes, for example, green represented by using both the C ink and the Y ink, particularly dark green represented by using both the relatively large amounts of the C ink and the Y ink. Further, the color difference generation color is expressed using red, which is expressed using both the M ink and the Y ink, and blue, C, M, Y ink which is expressed using both the C ink and the M ink. Gray. In the color evaluation information CI, a larger weight Wt is associated with the grid GD corresponding to these color difference generation colors than the grid GD corresponding to other colors.

A-3. Image Processing FIG. 5 is a flowchart of the image processing A of the first embodiment. The CPU 310 of the terminal device 300 (FIG. 1) starts the image processing of FIG. 5 based on a print instruction from the user. The print instruction includes designation of target image data corresponding to the print image OI (FIG. 3) to be printed. In the present embodiment, the target image data is, for example, RGB image data that represents the color of each pixel with RGB values. If the target image data is not RGB image data, the CPU 310 performs a rasterizing process on the target image data to convert the target image data into RGB image data.

  In S105, the CPU 310 acquires one piece of target pixel data from a plurality of pixel data (RGB values) included in the target image data. FIG. 6 is a diagram illustrating a part of the print image OI. FIG. 6A shows three partial images PI1 to PI3 of the print image OI described above.

  In the target image indicated by the target image data, a plurality of pixels are arranged in a matrix along the X direction and the Y direction. A line composed of a plurality of pixels for one row arranged in the X direction is called a raster line. In this embodiment, a plurality of raster lines included in the target image are sequentially processed from the + Y side to the -Y side, and a plurality of pixels constituting one raster line are processed from the -X side. Processing is sequentially performed toward the + X side. For this reason, as shown in FIG. 6A, for example, as shown by arrows in FIG. 6A, a plurality of pixels corresponding to the partial image PI2 are sequentially arranged from the pixel at the upper left corner to the pixel of interest. Is selected as Then, the value (RGB value) of the target pixel is acquired as target pixel data.

  In S115, the CPU 310 determines whether or not the target printing direction has been determined to be the immediately preceding printing direction. Here, the partial image PI corresponding to the current target pixel is also referred to as a target partial image. The target print direction is the print direction (forward direction or return direction) of the partial print for printing the target partial image. If the target print direction has been determined to be the immediately preceding print direction in S155 described below, it is determined that the target print direction has been determined to be the previous print direction. Here, the immediately preceding printing direction is the printing direction of the partial printing immediately before the partial printing for printing the target partial image.

  If the target printing direction has been determined to be the immediately preceding printing direction (S115: YES), in S120, the CPU 310 uses the profile corresponding to the immediately preceding printing direction among the outgoing path profile PF1 and the returning path profile PF2. Then, the target pixel data is color-converted. That is, the target pixel data (RGB values) is converted to CMYK values.

  If the target printing direction has not been determined (S115: NO), in S125, the CPU 310 uses the profile corresponding to the reverse direction of the immediately preceding printing direction, out of the outward profile PF1 and the return profile PF2. Then, the target pixel data is color-converted. That is, the target pixel data (RGB values) is converted to CMYK values.

  In S130, the CPU 310 performs a halftone process on the color-converted target pixel data. The halftone process is a process of generating data (also referred to as dot data) indicating a dot formation state for each CMYK component for a target 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”. In the present embodiment, the halftone processing is performed using a known error collection method.

  In S135, the CPU 310 determines the nozzle NZ corresponding to the pixel of interest. That is, when forming a dot corresponding to the target pixel, the CPU 310 determines the nozzle NZ used for forming the dot for each CMYK component. In the buffer area 331, a nozzle buffer for storing dot data for the target partial print is secured. The dot data corresponding to the target pixel is stored in the nozzle buffer at an address corresponding to the determined nozzle NZ.

  In S140, the CPU 310 determines whether the target printing direction has not been determined and whether all the pixel data of the target determination area has been acquired as the target pixel data. If the target printing direction has not been determined to be the immediately preceding printing direction in S155 described later, it is determined that the target printing direction has not been determined. As shown in FIG. 6A, a plurality of determination areas BL obtained by dividing each partial image PI into a plurality are set in the print image OI. The shape of the determination area BL is rectangular. The plurality of determination regions BL are arranged in a lattice pattern without gaps along the X direction and the Y direction. The number BH of pixels in the Y direction and the number BW of pixels in the X direction of the determination area BL are determined in advance. The attention determination area is a determination area BL corresponding to the attention pixel. For example, when the pixel PXa located at the lower right corner of the determination area BLa in FIG. 6A is the target pixel, all the pixel data corresponding to the determination area BLa has been acquired as the target pixel data. Is determined.

  If the target print direction has been determined, or if some pixel data of the target determination area has not been acquired (S140: NO), the CPU 310 returns the process to S105. If the target printing direction has not been determined and if all the pixel data in the target determination area has been acquired as the target pixel data (S140: YES), in S145, the CPU 310 calculates the evaluation value EV of the target determination area. I do.

  Specifically, the weight Wt corresponding to each of the plurality of pixels in the attention determination area is determined. The weight Wt is determined with reference to the above-described color evaluation information CI (FIG. 4). That is, Wt corresponding to each pixel is calculated by interpolation based on a plurality of weights Wt corresponding to a plurality of grids GD close to the RGB values (pixel data) of each pixel. The average value of the plurality of weights Wt corresponding to the plurality of pixels is calculated as the evaluation value EV of the attention determination area. The fact that the evaluation value EV of the attention determination area is large means that the color difference between the reciprocating motions of the image in the attention determination area is large.

  In S150, CPU 310 determines whether or not evaluation value EV of the attention determination area is equal to or greater than threshold value THv. If the evaluation value EV is less than the threshold value THv (S150: NO), the CPU 310 advances the processing to S175. If the evaluation value EV is equal to or greater than the threshold value THv (S150: YES), in S155, the CPU 310 determines the target printing direction to be the immediately preceding printing direction.

  In S160, the CPU 310 executes a recolor conversion process. That is, the CPU 310 performs the color conversion again on all the pixel data processed as the target pixel data up to the present. The pixel data processed so far is color-converted using the profile corresponding to the reverse direction of the immediately preceding printing direction, out of the forward pass profile PF1 and the return pass profile PF2 (S125). On the other hand, in the re-color conversion processing, the color conversion is performed using the profile corresponding to the immediately preceding printing direction among the outward path profile PF1 and the return path profile PF2.

  In S165, CPU 310 executes a re-halftone process. That is, in S160, CPU 310 again performs halftone processing on all the color-converted pixel data, and again generates dot data corresponding to the pixel data. The halftone processing of this embodiment is an error collection method. Therefore, in order to execute the halftone processing again, the calculation is performed when the halftone processing is executed for a predetermined number (for example, 1 to 2) of raster lines adjacent to the + Y side of the target partial image. Error value is required. For example, when the partial image PI2 in FIG. 6A is the target partial image, an error value for a predetermined number of raster lines RL1 located at the -Y side end of the partial image PI1 is required. This error value is stored in the buffer area 331 in S185 described later.

  In S170, the CPU 310 determines a nozzle NZ corresponding to the generated dot data. The dot data generated again is stored in the nozzle buffer at an address corresponding to the determined nozzle NZ. As a result, the dot data stored for each pixel of interest in the nozzle buffer in S135 described above is overwritten by the dot data generated again in S165 and erased.

  In S175, the CPU 310 determines whether or not all the pixel data of the target partial image data has been processed as the target pixel data. The target partial image data is data corresponding to the target partial image among the target image data. If the target partial image data includes unprocessed pixel data (S175: NO), the CPU 310 returns the processing to S105. If all the pixel data of the target partial image data has been processed as the target pixel data (S175: YES), at this point, all the dot data corresponding to the target partial image is stored in the nozzle buffer. That is, at this point, partial print data for printing the target partial image has been completed in the nozzle buffer. In this case, the CPU 310 advances the processing to S180.

  In S180, the CPU 310 determines whether or not the print direction of interest has been determined to be the immediately preceding print direction. If the target print direction has been determined to be the immediately preceding print direction (S180: YES), the CPU 310 advances the process to S190. If the target print direction has not been determined (S180: NO), in S185, the CPU 310 determines the target print direction to be the reverse of the immediately preceding print direction. That is, when the partial print data is completed without determining the target print direction in S155 as the immediately preceding print direction, the target print direction is determined in a direction opposite to the immediately preceding print direction.

  In S190, the CPU 310 transmits the generated partial print data and the direction information indicating the determined target print direction to the printer 200. When the printer 200 receives the partial print data and the direction information, the CPU 210 of the printer 200 executes the partial print according to the partial print data and the direction information. For example, when the direction information indicates the forward path direction, the CPU 210 executes the forward path printing to print the target partial image, and when the direction information indicates the backward path direction, executes the return path printing to execute the target path image. Print the image.

  In S195, the CPU 310 stores the error value for the case where the re-halftone process in S165 is executed in the process with the next partial image as the target partial image in the buffer area 331. For example, when the partial image PI2 in FIG. 6A is the target partial image, the error value of the predetermined number of raster lines RL2 located at the end on the −Y side of the partial image PI2 is the buffer area 331. Is stored in

  In S198, the CPU 310 determines whether or not all the partial image data of the print image OI to be printed has been processed. If there is unprocessed partial image data (S198: NO), the CPU 310 returns the process to S105. If all the partial image data has been processed (S198: YES), the CPU 310 ends the image processing A.

  The print image OI printed by the image processing A described above will be described. As shown in FIG. 4, in the printing of this embodiment, in principle, forward printing and backward printing are executed alternately (S125 in FIG. 5). As a result, the printing time required for printing can be reduced.

  Further, according to the image processing A, the CPU 310 uses the focused partial image data to determine the focused printing direction as one of the forward direction and the backward direction (S150, S155, S180, S185 in FIG. 5). ). As a result, the target partial image is printed in a print direction appropriate for the target partial image to be printed. Thus, it is possible to suppress the occurrence of color unevenness due to different printing directions.

  For example, a partial image of interest printed using the first partial print data (that is, one of a forward partial image and a return partial image), and a partial image of interest printed using the second partial print data If it is determined that the color difference (that is, the color difference between reciprocation) between the forward pass image and the return pass image is smaller than the reference, the target print direction is the immediately preceding print direction. Is determined in the opposite direction. Specifically, as described above, when the evaluation values EV of all the determination areas BL in the target partial image are smaller than the threshold value (NO in S180 of FIG. 5), the target print direction is the same as the immediately preceding print direction. It is determined in the opposite direction (S185 in FIG. 5). If it is determined that the color difference is equal to or greater than the reference, the target printing direction is determined to be the immediately preceding printing direction. Specifically, as described above, when the evaluation value EV of at least one determination area BL in the target partial image is equal to or larger than the threshold (YES in S150 of FIG. 5), the target print direction is set to the immediately preceding print. The direction is determined (S155 in FIG. 5). As a result, when the color difference is less than the reference, the printing speed can be improved, and when the color difference is equal to or more than the reference, a decrease in image quality due to the color difference can be suppressed.

  For example, in the example of FIG. 3, the hatched partial images PI2, PI3, and PI8 are partial images for which the color difference is determined to be equal to or more than the reference, and the remaining unhatched partial images PI1, PI4 to PI7. , PI9, and PI10 are partial images for which it is determined that the color difference is less than the reference. As shown in FIG. 3, the hatched partial images PI2, PI3, and PI8 are printed in the same print direction as the print direction of the partial images PI1, PI2, and PI7 that are printed immediately before. In this case, as indicated by a broken-line arrow in FIG. 3, main scanning is performed without forming dots between the partial printing for printing the partial image and the immediately preceding partial printing. A main scan performed without forming dots (that is, without printing a partial image) in this manner is also referred to as a non-print main scan.

  By performing the non-printing main scanning, the printing time required for printing becomes longer as compared with the case where the non-printing main scanning is not performed. A decrease in image quality can be suppressed. For example, the two partial images PI2 and PI3 in FIG. 3 are adjacent to each other and have a color difference equal to or greater than a reference. Can stand out. In the present embodiment, as shown in FIG. 3, since the two partial images PI2 and PI3 are printed in the same printing direction, there is no color difference between the two partial images PI2 and PI3 during the reciprocation.

  Here, as described above, in the color evaluation information CI, a weight Wt greater than other colors is associated with the color difference generation color. Therefore, the fact that the evaluation value EV of at least one determination region BL is equal to or greater than the threshold value means that the target partial image includes color difference generation color pixels that are equal to or greater than the reference, and the evaluation values EV of all the determination regions BL. Is smaller than the threshold value, it means that the target partial image does not include a color difference generation color pixel equal to or higher than the reference. The color difference generating color pixel is a pixel having the above-described color difference generating color. As described above, in the present embodiment, it can be said that when the target partial image includes a color difference generating color pixel that is equal to or greater than the reference, the color difference (the color difference between the two directions) is determined to be equal to or greater than the reference. As a result, it is possible to appropriately suppress a decrease in image quality due to a color difference caused by overlapping of two or more types of ink.

  Here, in the image processing A, the CPU 310 executes a first generation process (S125, S130, S135 in FIG. 5) including a first color conversion process (S125 in FIG. 5) on the focused partial image data. obtain. This first color conversion process is performed using the profile corresponding to the direction opposite to the immediately preceding printing direction among the profiles PF1 and PF2. As described above, the first generation process is a process of generating the first partial print data for performing the partial print in the direction opposite to the immediately preceding print direction. In addition, the CPU 310 performs a second generation process (S160, S165, S170, S120, S130, S135 in FIG. 5) including a second color conversion process (S160, S120 in FIG. 5) on the target partial image data. You can do it. This second color conversion processing is performed using the profile corresponding to the immediately preceding printing direction among the profiles PF1 and PF2. As described above, the second generation process is a process of generating the second partial print data for performing the partial print in the immediately preceding print direction. Then, the CPU 310 outputs the first partial print data to the printer 200 when the target print direction is determined to be the reverse direction of the immediately preceding print direction, and outputs the first partial print data when the target print direction is determined to be the immediately preceding print direction. The second print data is output to the printer 200 (S190 in FIG. 5).

  According to the image processing A, the profiles PF1 and PF2 used in the first color conversion process and the second color conversion process convert specific RGB values using the outward profile PF1 as described above. The color of the forward pass partial image printed based on the obtained CMYK value and the color of the return pass partial image printed based on the CMYK value obtained by converting the specific RGB value using the return pass profile PF2. , Has been adjusted to get closer. As a result, for example, in comparison to the case where one type of profile is used in both forward printing and backward printing, the focused partial image printed in forward printing and the focused partial image printed in backward printing are compared. It is more likely that the color difference that occurs between is less than the criterion. As a result, there is a high possibility that the target printing direction is determined to be opposite to the immediately preceding printing direction. As a result, the printing speed of printing using forward printing and backward printing can be improved.

  Further, according to the image processing A, the first generation processing is started from a point in time when the target printing direction has not been determined (NO in S115 of FIG. 5). Further, the first generation processing is interrupted when the target printing direction is determined to be the immediately preceding printing direction (the same direction as the printing direction of the immediately preceding partial printing) (YES in S115 of FIG. 5). The first generation process is executed without interruption (ie, completed) when the target print direction is determined to be the reverse direction of the immediately preceding print direction (S185 in FIG. 5). Then, the second generation processing is started after the target print direction is determined to be the immediately preceding print direction (YES in S150 of FIG. 5, YES in S115).

  As described above, the first generation processing is started from a point in time when the target printing direction is not determined. Therefore, when the target printing direction is determined to be the reverse direction of the immediately preceding printing direction, the first partial printing is promptly performed. Data is generated. As a result, for example, even if it takes a relatively long time to determine the target printing direction, if the target printing direction is determined to be the reverse direction of the immediately preceding printing direction, that is, forward printing and returning printing are used. When printing (bidirectional printing) is performed, printing can be started immediately using the first partial print data. Therefore, a decrease in printing speed can be suppressed. For example, when compared with a case where the first generation processing and the second generation processing are performed in parallel (for example, a third embodiment described later), a case where the target printing direction is determined to be the opposite direction to the immediately preceding printing direction. Can quickly generate the first partial print data. As can be understood from the above description, according to the image processing A, it is possible to suppress a decrease in printing speed while suppressing the occurrence of color unevenness in printing using forward printing and backward printing.

  When the first generation processing and the second generation processing are performed in parallel (for example, a third embodiment described later), the data generated in the first generation processing and the data generated in the second generation processing are generated. It is necessary to secure a buffer area 331 for respectively storing the data to be processed. On the other hand, according to the image processing A, the first generation process is interrupted when the target print direction is determined to be the immediately preceding print direction, and the second generation process is performed when the target print direction is set to the immediately preceding print direction. Since the processing is started after the determination, only the buffer area 331 for storing one of the data generated in the first generation processing and the data generated in the second generation processing may be secured. Therefore, the capacity of the memory as the buffer area 331 necessary for generating the partial print data can be reduced.

  Here, it can be said that the fact that the evaluation value EV of the attention determination area is equal to or larger than the threshold is a specific condition indicating that the attention printing direction should be the immediately preceding printing direction. According to the image processing A, the CPU 310 determines whether or not the specific condition is satisfied using a part of the target partial image data (that is, the data corresponding to the determination area BL) (see FIG. 5 (S150 in FIG. 5), when the specific condition is satisfied (YES in S150 in FIG. 5), the target print direction is determined to be the immediately preceding print direction (S155 in FIG. 5). As a result, for example, the time required to determine the target printing direction as the immediately preceding printing direction can be reduced as compared with the case where the target printing direction is determined using the entire target partial image data. For example, if the target print direction is determined to be the immediately preceding print direction, the first generation process is interrupted to start the second generation process, and the first generation process performed up to that point is started. Is wasted. However, according to the image processing A, the first generation processing can be interrupted earlier and the second generation processing can be started as compared with the case where the target print direction is determined using the entire target partial image data. it can. As a result, even when the target print direction is determined to be the immediately preceding print direction, the first generation processing is prevented from being performed uselessly, and the printing speed can be improved.

  Further, according to the image processing A, when at least one determination area BL satisfies a specific condition (in the image processing A, the evaluation value EV is equal to or more than a threshold), the target printing direction is determined to be the immediately preceding printing direction ( S150 and S155 in FIG. 5). Therefore, the time required to determine the target printing direction as the immediately preceding printing direction can be further reduced.

  Further, according to the image processing A, the CPU 310 obtains the specific image data each time a plurality of specific pixel data among the plurality of pixel data included in the target partial image data is obtained as the target pixel data. Using the pixel data, it is determined whether the specific condition is satisfied (S140 to S150 in FIG. 5). Specifically, in the image processing A, the plurality of specific pixel data is pixel data to be processed last in each determination region BL (for example, the pixel PXa in the determination region BLa in FIG. 6A). Each time these pixels are acquired as target pixel data, it is determined whether a specific condition is satisfied. If it is determined that any specific pixel data is acquired and the specific condition is satisfied (YES in S150 of FIG. 5), the target print direction is determined to be the immediately preceding print direction (FIG. 5). S155 of No. 5). Then, when the acquisition of a plurality of specific pixel data is completed without satisfying the specific condition (NO in S180 of FIG. 5), the target print direction is determined to be the reverse direction of the immediately preceding print direction. (S185 in FIG. 5). As a result, when the target print direction is determined to be the immediately preceding print direction, the time required for determining the target print direction can be reduced.

  Further, according to the image processing A, the first color conversion processing (S125 in FIG. 5) and the first color conversion processing generated by the first color conversion processing are performed for each pixel from the point in time when the target printing direction is not determined. A unit process including a first halftone process using the processed data (CMYK values) (S130 in FIG. 5) is started. As a result, after the first color conversion process is performed on the entire target partial image data, the buffer region 331 is required more than when the first halftone process is performed (for example, a second embodiment described later). Memory capacity can be reduced. When performing the first halftone process after performing the first color conversion process on the entire target partial image data, the buffer region 331 storing the CMYK values of all the pixels in the target partial image This is because, according to the image processing A, it is only necessary to hold the CMYK values for one pixel. Further, at S185 in FIG. 5, when the target printing direction is determined to be the reverse of the immediately preceding printing direction, the first partial print data for printing the target partial image has been generated. Is determined in the direction opposite to the immediately preceding printing direction, the printer 200 can immediately start printing the target partial image. When the first halftone process is performed after the first color conversion process is performed on the entire target partial image data, the CMYK values of the target partial image stored in the buffer area 331 are used. It is necessary to obtain CMYK values for each pixel and perform halftone processing. On the other hand, according to the image processing A, color conversion and halftone processing are performed as a set on the RGB values acquired once. For this reason, the time required to generate the first partial print data can be reduced because the process of acquiring the CMYK values one pixel at a time becomes unnecessary. Therefore, the printing speed can be further improved.

B. Second Embodiment In the second embodiment, image processing B is executed instead of the image processing A (FIG. 5) of the first embodiment. FIG. 7 is a flowchart of the image processing B of the second embodiment. In the flowchart of FIG. 7, the same steps as those in the image processing A in FIG. 5 are denoted by the same reference numerals as those in FIG. 5, and steps different from those in the image processing A in FIG. ing.

  In S105B of the image processing B in FIG. 7, the target pixel data is obtained one by one, but the order of obtaining the target pixel data is different from that in S105 of the image processing A in FIG. In S105B of the image processing B, as shown in FIG. 6B, after the pixel data corresponding to all the pixels in the determination area BL, which is the attention determination area, is acquired as the attention pixel data, it is adjacent to the + X side. Pixel data corresponding to a pixel in the next determination area BL is obtained. Then, after all of the plurality of determination regions BL arranged in the X direction are processed as the attention determination region, the plurality of determination regions BL adjacent to the plurality of determination regions BL on the −Y side are sequentially arranged from the −X side. Is processed. The target pixel data can be obtained in such an order because, as described later, halftone processing using the error collection method is performed after all the pixel data of the target partial image data are color-converted. is there.

  In image processing B of FIG. 7, S130 and S135 of image processing A of FIG. 5 are not executed. For this reason, in the image processing B, after the color conversion processing is performed on the target pixel data in S120 or S125, the CPU 310 advances the processing to S140.

  In the image processing B in FIG. 7, after the target print direction is determined to be the immediately preceding print direction in S155, S158B and S160B are executed instead of S160 to S170 in FIG.

  In S158B, the CPU 310 determines one or more processed determination areas BL as a determination area BL for performing recolor conversion or a determination area BL for not performing recolor conversion. For example, it is assumed that when the determination area BLb in FIG. 6B is the attention determination area, it is determined that the evaluation value EV of the attention determination area is equal to or larger than the threshold value THv (YES in S150 in FIG. 7). In this case, in S158B, the CPU 310 converts each of the processed determination areas BL hatched in FIG. 6B into a determination area BL for performing recolor conversion and a determination area for not performing recolor conversion. BL. Specifically, among the processed determination areas BL, a determination area BL in which the corresponding evaluation value EV is equal to or greater than a threshold value THs smaller than the threshold value THv is determined as a determination area BL for performing recolor conversion, and the corresponding evaluation area BL is determined. The determination region BL in which the value EV is less than the threshold value THs is determined as a determination region BL in which recolor conversion is not performed.

  In S160B, the CPU 310 performs the recolor conversion process on the pixel data corresponding to all the pixels in the determination region BL that has been determined to perform the recolor conversion among the processed determination region BL. The CPU 310 does not perform the recolor conversion processing on the pixel data corresponding to the pixels in the determination area BL that is determined not to perform the recolor conversion among the processed determination areas BL. In the recolor conversion process, as in S160 of FIG. 5, color conversion is performed using the profile corresponding to the immediately preceding print direction, out of the forward pass profile PF1 and the return pass profile PF2. In the buffer area 331 in which the color-converted pixel data (CMYK values) are stored, the CMYK values corresponding to the pixels in the determination area BL determined to perform the recolor conversion are the CMYK values generated by the reconversion processing. Will be overwritten. In the buffer area 331, the CMYK values corresponding to the pixels in the determination area BL determined not to perform the recolor conversion are not overwritten.

  In the image processing B, S186B is executed after the color conversion processing has been performed for all the partial image data of interest, that is, after S180 or S185.

  In S186B, the CPU 310 performs a halftone process on all the pixel data (CMYK values) of the target partial image data after the color conversion process. As a result, all dot data corresponding to the target partial image data is generated. That is, if the target print direction is determined to be the reverse direction of the immediately preceding print direction in S185, the first halftone process is executed. If the target print direction is determined to be the immediately preceding print direction in S155, , A second halftone process is executed. The first halftone process is executed using the processed data (CMYK values) generated in the first color conversion process (S125 in FIG. 7). The second halftone process includes the processed data (CMYK values) generated in the second color conversion process (S160B and S120 in FIG. 7) performed after the target print direction is determined, and the first color conversion. The processing is performed using the data corresponding to the determination area BL in which the re-conversion processing is not performed among the processed data generated in the processing (S125 in FIG. 7). In S188B, the CPU 310 determines a corresponding nozzle NZ for all dot data. As a result, partial print data for printing the target partial image is generated. That is, the first partial print data is generated when the target print direction is determined to be the reverse direction of the immediately preceding print direction, and the second partial print data is generated when the target print direction is determined to be the previous print direction. Data is generated.

  Other processing of the image processing B in FIG. 7 is the same as the image processing A in FIG.

  According to the image processing B of the present embodiment described above, the halftone processing is started after the color conversion processing is completed for the partial image data of interest (S186B in FIG. 7). That is, when the target print direction is determined to be the reverse direction of the immediately preceding print direction in S185, the CPU 310 executes the first halftone process after determining the target print direction to be the reverse direction of the immediately preceding print direction. I do. Then, when the target printing direction is determined to be the immediately preceding printing direction in S155, the CPU 310 executes the second generation processing including the second halftone processing after the target printing direction is determined to be the immediately preceding printing direction. I do. As a result, whether the target printing direction is determined to be the reverse direction of the immediately preceding printing direction or the immediately preceding printing direction, it is possible to suppress unnecessary halftone processing from being performed. In other words, even if the target print direction is determined to be the immediately preceding print direction, the only process that needs to be executed again is the color conversion process. Therefore, when the target printing direction is determined to be the immediately preceding printing direction, a decrease in printing speed can be suppressed.

  Further, according to the image processing B, when the target printing direction is determined to be the immediately preceding printing direction (S155 in FIG. 7), the CPU 310 generates the interrupted first color conversion process (S125 in FIG. 7). The usable data is determined from the processed data (CMYK values) (S158B in FIG. 7), and a second color conversion process is performed on data that does not correspond to the usable data (S160B in FIG. 7). The second color conversion process is not performed on data corresponding to available data. Then, when the target print direction is determined to be the immediately preceding print direction, the CPU 310 determines the CMYK values generated by the second color conversion processing (S120 and S160B in FIG. 7) and the interrupted first generation processing ( The second partial print data is generated using the available CMYK values generated by the first color conversion processing) (S186B, S188B). As a result, according to the image processing B, since the second color conversion processing is not performed on the data corresponding to the available data, the printing time can be reduced when the printing direction is determined to be the immediately preceding printing direction. obtain.

  Further, as described above, the available CMYK values are the CMYK values corresponding to the determination area BL in which the corresponding evaluation value EV is less than the threshold value THs. The CMYK value corresponding to the determination area BL in which the corresponding evaluation value EV is less than the threshold value THs is based on the color difference between the case of printing in forward printing and the case of printing in return printing (color difference between round trip). It can be said that the data corresponds to the part determined to be as follows. As a result, only the CMYK values generated by the first color conversion process, that is, the regions that can be determined to be unlikely to cause a color difference even if a profile corresponding to a direction different from the target printing direction is used, are used as the second values. The color conversion processing is omitted. Therefore, it is possible to suppress the image quality of the image to be printed from being degraded despite omitting a part of the second color conversion processing.

  Further, according to the image processing B, in S105 of FIG. 7, target pixel data is obtained in the order shown in FIG. As a result, for example, in the order shown in FIG. 6A, the determination region BL located on the −X side, for example, the determination region BLa in FIG. The determination using the evaluation value EV of BLb (S150) is performed at an early stage. As a result, when the target print direction is determined to be the immediately preceding print direction (S155), the time required to determine the target print direction can be reduced. As a result, when the target print direction is determined to be the immediately preceding print direction, it is possible to reduce the amount of useless execution of the first generation process.

  Here, when a profile corresponding to a direction different from the target printing direction is used, a round-trip color difference is more likely to occur than when a profile corresponding to the target printing direction is used. For this reason, when determining usable data, it is preferable to more strictly determine that the color of the image in the determination area BL is a color in which the color difference between the reciprocations is unlikely to occur. According to the image processing B, the threshold value THs used in determining available data in S158B is smaller than the threshold value THv used in determining the target printing direction to the immediately preceding printing direction in S150. As a result, it is possible to appropriately suppress the deterioration of the image quality of the image to be printed.

C. Third embodiment

  In the third embodiment, the CPU 310 includes a plurality of logical processors, and a function of improving the overall processing speed by allocating logical processors to each of two or more threads and simultaneously processing them (also referred to as a multi-thread processing function). ). For example, a plurality of logical processors may be realized by a plurality of physical cores, a single physical core may be realized by providing a plurality of logical cores, or a combination of these. Is also good. As a technology in which one physical core provides a plurality of logical cores, for example, Intel (registered trademark) hyper-threading technology is known.

  In the third embodiment, image processing C is executed instead of image processing A (FIG. 5) and image processing B (FIG. 7). FIG. 8 is a flowchart of the image processing C of the third embodiment. In the flowchart of FIG. 8, the same steps as those in the image processing B in FIG. 7 are denoted by the same reference numerals as those in FIG. 7, and steps different from those in the image processing B in FIG. ing.

  In the image processing C of FIG. 8, when it is determined in S115 that the target print direction has not been determined to be the immediately preceding print direction (S115: NO), S125C and S127C are replaced with S125C in FIG. It is executed in parallel by the multi-thread function.

  In S125C, the CPU 310 color-converts the target pixel data using the outward path profile PF1. As a result, CMYK values for the forward path are generated. In S127C, the CPU 310 converts the color of the target pixel data using the return path profile PF2. As a result, a CMYK value for the return path is generated. These two types of CMYK values are stored in different areas of the buffer area 331, respectively.

  In the image processing C in FIG. 8, after the target printing direction is determined to be the immediately preceding printing direction in S155, S158B and S160B in FIG. 7 are not executed.

  As described above, in the image processing C, when the target print direction is determined to be the immediately preceding print direction in S155, the forward CMYK is performed in S125C and S127C until the target print direction is determined to be the immediately preceding print direction. Both the value and the CMYK value for the return path are generated and stored in the buffer area 331. After the target print direction is determined to be the immediately preceding print direction, only the CMYK values corresponding to the immediately preceding print direction among the CMYK values for the forward pass and the CMYK values for the return pass are generated in S120. The generation of CMYK values corresponding to the opposite direction is interrupted.

  Then, in the image processing C, if the target print direction is determined to be the reverse direction of the immediately preceding print direction in S185, both the forward CMYK value and the return CMYK value are used in S125C and S127C. Generated for the entire partial image.

  In the image processing C of FIG. 8, similarly to the image processing B of FIG. 7, after the color conversion processing is performed on all the target partial image data, that is, after S180 or S185, the halftone processing is performed in S186B. The processing is executed.

  That is, if the target print direction is determined to be the reverse direction of the immediately preceding print direction in S185, the corresponding one of the forward CMYK value and the return CMYK value corresponds to the reverse direction of the previous print direction in S186B. Halftone processing is performed on the CMYK partial image data composed of the CMYK values to be processed. As a result, first partial print data for printing the target partial image in the direction opposite to the immediately preceding print direction is generated.

  If the target printing direction is determined to be the immediately preceding printing direction in S155, in S186B, of the CMYK values for the forward path and the CMYK values for the returning path, the CMYK values are formed from the CMYK values corresponding to the immediately preceding printing direction. Halftone processing is performed on the partial image data. Thereby, the second partial print data for printing the target partial image in the immediately preceding print direction is generated.

  According to the image processing C described above, the first generation processing for generating the first partial print data and the second generation processing for generating the second partial image data include the target print. The processing is started in parallel from the time when the direction is not determined (S125C and S127C in FIG. 8). As a result, no matter which print direction is determined, the partial print data can be generated relatively early. For example, even when it takes a relatively long time to determine the target print direction, the partial print data can be generated early. As a result, the printing speed can be improved.

  Further, according to the image processing C, after the target partial image is determined in the immediately preceding printing direction (S115 in FIG. 8: NO), only the color conversion using the profile corresponding to the immediately preceding printing direction (S120 in FIG. 8) is performed. Color conversion using the other profile is not performed. That is, when the target partial image is determined in the immediately preceding printing direction, at that time, the first generation processing is interrupted, and only the second generation processing is completed. After the target partial image is determined in the reverse direction of the immediately preceding print direction (S185 in FIG. 8), the CMYK partial image data generated by the color conversion using the profile corresponding to the reverse direction of the immediately preceding print direction is executed. Only the halftone process is performed (S186B in FIG. 8), and the halftone process is not performed on the CMYK partial image data generated by the color conversion using the other profile. That is, when the target partial image is determined in the direction opposite to the immediately preceding printing direction, at that time, the second generation processing is interrupted, and only the first generation processing is completed. As described above, after the target print direction is determined, only one of the first generation processing and the second generation processing is executed, so that the processing load for generating the partial print data can be reduced. .

  Further, according to the image processing C, a part of the first generation processing and a part of the second generation processing are processed in parallel using the multi-thread processing function of the CPU 310, so that the partial print data Generation can be accelerated.

D. Fourth Embodiment In a fourth embodiment, image processing D is executed instead of image processing A (FIG. 5), image processing B (FIG. 7), and image processing C (FIG. 8). FIG. 9 is a flowchart of the image processing D of the fourth embodiment.

  In S205, the CPU 310 acquires target pixel data in the order shown in FIG. 6B, for example, as in S105 of FIG. However, in this embodiment, instead of acquiring all pixels in the attention determination area as attention pixel data, a part of the pixels in the attention determination area are selectively acquired. As described above, the attention determination area is an area corresponding to the attention pixel data among the plurality of determination areas BL (FIG. 6). For example, among the plurality of pixel data corresponding to the attention determination area, the CPU 310 acquires only the data of the pixels whose X coordinate and Y coordinate are odd numbers as attention pixel data. As a result, the processing time required to determine the target printing direction can be reduced.

  In S210, the CPU 310 determines whether all the pixel data to be acquired have been acquired from among the plurality of pixel data corresponding to the attention determination area. For example, it is determined whether or not the data of all the pixels having an odd X coordinate and Y coordinate among several pieces of pixel data corresponding to the attention determination area has been obtained.

  If some of the pixel data to be acquired has not been acquired (S210: NO), the CPU 310 returns the processing to S205. When all the pixel data to be acquired have been acquired (S210: YES), in S214, the CPU 310 calculates the evaluation value EV of the attention determination area, and in S220, when the evaluation value EV is equal to or larger than the threshold value THv. It is determined whether or not there is.

  If the evaluation value EV is equal to or greater than the threshold value THv (S220: YES), in S225, the CPU 310 determines the target printing direction to be the immediately preceding printing direction, and proceeds to S245. If the evaluation value EV is less than the threshold value THv (S220: NO), in S230, the CPU 310 determines whether or not all the determination areas BL in the target partial image have been processed. If there is an unprocessed determination area (S230: NO), the CPU 310 returns the processing to S205. If all the determination areas BL in the target partial image have been processed (S230: YES), in S240, the CPU 310 determines the target print direction to be the reverse of the immediately preceding print direction, and proceeds to S245. .

  In S245, the CPU 310 acquires the target pixel data in the order shown in FIG. 6A, for example, as in S105 in FIG. In S250, the CPU 310 color-converts the target pixel data using the profile corresponding to the determined target print direction among the forward pass profile PF1 and the return pass profile PF2. In S255, the CPU 310 executes a halftone process on the color-converted target pixel data. In S260, the CPU 310 determines the nozzle NZ corresponding to the pixel of interest.

  In S265, the CPU 310 determines whether all pixel data of the target partial image data has been processed as target pixel data. If the target partial image data includes unprocessed pixel data (S265: NO), the CPU 310 returns the process to S245. If all the pixel data of the target partial image data have been processed as the target pixel data (S265: YES), in S270, the CPU 310 determines the generated partial print data and the direction indicating the determined target print direction. And the information to the printer 200. When the printer 200 receives the partial print data and the direction information, the CPU 210 of the printer 200 executes the partial print according to the partial print data and the direction information.

  In S275, the CPU 310 determines whether or not all the partial image data of the print image OI to be printed has been processed. If there is unprocessed partial image data (S275: NO), the CPU 310 returns the processing to S205. If all the partial image data has been processed (S275: YES), the CPU 310 ends the image processing D.

  According to the image processing D described above, after the target print direction is determined in S205 to S240, in S245 to S265, the determined target print of the first generation process and the second generation process is determined. Processing corresponding to the direction is performed. As a result, even when the target print direction is determined to be the immediately preceding print direction, the first generation processing is not executed wastefully. Further, even when the direction of interest is determined to be the reverse direction of the immediately preceding printing direction, the second generation processing is not executed unnecessarily. As a result, the same printing speed can be realized no matter which printing direction is determined.

  Also, since the first generation processing and the second generation processing are not performed in parallel, the data generated by the first generation processing and the data generated by the second generation processing are Both need not be stored in the buffer area 331. For this reason, for example, compared to the image processing C, the capacity of the memory required as the buffer area 331 can be reduced.

E. FIG. Fifth Embodiment In the fifth embodiment, the above-described three types of processing of image processing A (FIG. 5), image processing C (FIG. 8), and image processing D (FIG. 9) are selectively used. FIG. 10 is a flowchart of the process of the fifth embodiment.

  The process in FIG. 10 is started based on, for example, a print instruction from a user. In S310, the CPU 310 determines whether or not the CPU 310 has the above-described multi-thread processing function. For example, the system information of the operating system includes information indicating the number of logical processors indicating the number of threads that can be processed simultaneously by the CPU 310. The CPU 310 specifies the number of logical processors of the CPU 310 with reference to the system information. When the number of logical processors of the CPU 310 is two or more, the CPU 310 determines that the CPU 310 has the multithread processing function described above. When the number of logical processors of the CPU 310 is 1, the CPU 310 determines that the CPU 310 does not have the multithread processing function described above. In the modified example, when the number of physical cores of the CPU 310 is two or more, it is determined that the CPU 310 has a multi-thread processing function. When the number of physical cores of the CPU 310 is one, the multi-thread processing function is provided. It may be determined that they have not.

  If the CPU 310 has the multi-thread processing function (S310: YES), the process proceeds to S320. If the CPU 310 does not have the multi-thread processing function (S310: NO), the process proceeds to S330.

  In S320, the CPU 310 determines whether the printer 200 has an unprocessed print job. The unprocessed print job includes partial print data for partial printing that has not been executed by the printer 200. For example, the CPU 310 inquires whether the printer 200 has an unprocessed print job. CPU 310 determines whether printer 200 has an unprocessed print job based on a response obtained from printer 200 in response to the inquiry. If there is an unprocessed print job in the printer 200 (S320: YES), the CPU 310 advances the process to S340. If there is no unprocessed print job in the printer 200 (S320: NO), the CPU 310 proceeds to S330.

  In S330, the CPU 310 determines whether the main object of the print image OI to be printed is a character, a photograph, or a drawing based on the print instruction. For example, the CPU 310 makes the determination based on the extension of the image data (image file) corresponding to the print image OI. Specifically, if the extension of the image file is a first type extension, the CPU 310 determines that the main object is a character. If the extension of the image file is the second type of extension, the CPU 310 determines that the main object is a drawing or a photograph. The first type extension includes, for example, “.txt”, “.doc”, and “.pdf”. The second type of extension includes, for example, “.jpg” and “.bmp”. If the main object of print image OI is a character (S330: YES), CPU 310 proceeds to S350. If the main object of the print image OI is a photograph or a drawing (S330: NO), the CPU 310 proceeds to S340.

  In S340, the CPU 310 acquires the capacity of the memory that can be used as the buffer area 331 for the process of generating the partial print data. In S345, CPU 310 determines whether or not the acquired available memory capacity is equal to or greater than threshold value THm. The threshold value THm is set, for example, to a capacity equivalent to twice the CMYK image data corresponding to one partial image. If the available memory capacity is equal to or greater than threshold THm (S345: YES), CPU 310 proceeds to S360. If the available memory capacity is less than the threshold value THm (S345: NO), the CPU 310 proceeds to S370.

  In S350, the CPU 310 executes the image processing A of FIG. In S360, CPU 310 executes image processing C in FIG. In S270, the CPU 310 executes the image processing D of FIG.

  However, when the image processing D of FIG. 9 is executed when the CPU 310 has the multi-thread processing function, the CPU 310 executes the image processing D using the multi-thread processing function. For example, the CPU 310 executes a process (S205 to S240 in FIG. 9) of determining a target printing direction for the first partial printing. When the target printing direction is determined for the first partial printing, the CPU 310 then determines the target printing direction for the (n + 1) -th (n is an integer of 1 or more) partial printing (see FIG. 9). S205 to S240), processing for generating partial print data for the n-th partial print (S245 to S275 in FIG. 9), and the processing are executed in parallel using the multi-thread processing function.

  According to the fifth embodiment described above, when the available memory capacity is equal to or larger than the threshold value THm (S345 in FIG. 10: YES), the first generation is performed from the time when the target print direction is not determined. Image processing C in which the processing and the second generation processing are started is executed (S360 in FIG. 10). That is, in this case, image processing that requires a relatively large memory capacity is executed. If the available memory capacity is less than the reference (S345 in FIG. 10: NO), after the target printing direction is determined, the determined one of the first generation processing and the second generation processing is determined. Image processing D, in which processing corresponding to the target print direction is started, is executed (S370 in FIG. 10). That is, in this case, image processing that requires a relatively small memory capacity is executed. As a result, an appropriate generation process can be executed according to the available memory capacity.

  Further, according to the fifth embodiment, when multi-thread processing is possible (S310: YES in FIG. 10), the image processing C and the image processing are performed on the condition that there is an unprocessed print job in the printer 200. D is executed (S360, S370 in FIG. 10). It can be said that the image processing C is processing in which the first generation processing and the second generation processing are started in parallel using multi-thread processing from the point in time when the target print direction has not been determined. The image processing D includes a process of determining the print direction of the next partial print and a process corresponding to the determined target print direction of the first generation process and the second generation process, which are performed by multi-thread processing. It can be said that the processing is executed in parallel using That is, in this case, when multi-thread processing is possible, image processing that can improve the processing speed is executed as compared with the case where multi-thread processing is not possible. If the multi-thread process is not possible (S310: NO in FIG. 10), the first generation process starts when the target print direction is undecided on condition that the main object is a character. Then, image processing A without starting the second generation processing is executed (S350 in FIG. 10). That is, in this case, even if the multi-thread processing is not used, if the target print direction is determined to be the reverse of the immediately preceding print direction, an image that can generate partial print data at a higher speed than other image processing can be used. The processing is executed. As a result, more appropriate image processing can be executed depending on whether multi-thread processing is possible.

  Further, according to the fifth embodiment, when there is an unprocessed print job in the printer 200 (S320: YES in FIG. 10), one of the image processing C and the image processing D is executed. (S360 and S370 in FIG. 10). That is, in this case, since the printer 200 is not in a state where printing can be started immediately, there is no large difference in processing time whether the target printing direction is the opposite direction to the immediately preceding printing direction or the immediately preceding printing direction. Image processing capable of stably generating partial print data is executed. Then, when there is no unprocessed print job in the printer 200 (S320: NO in FIG. 10), the image processing A is executed. That is, in this case, since the printer 200 is in a state where printing can be started immediately, the image processing A that may possibly generate the partial print data at the highest speed is executed. The image processing A can generate the partial print data fastest if the target print direction is opposite to the immediately preceding print direction. As a result, more appropriate image processing can be executed according to the presence or absence of a print job.

  Further, according to the fifth embodiment, when the image data corresponding to the print image OI is specified as image data in which a main object is a drawing or a photograph (S330 in FIG. 10: NO), the image One of the processing C and the image processing D is executed (S360, S370 in FIG. 10). Drawings or photographs are more likely to contain the color difference generating colors described above than text. For this reason, in this case, the possibility that the target printing direction is determined to be the immediately preceding printing direction is relatively high. Less image processing C and image processing D are performed. Then, when the image data is specified as the image data in which the main object is a character (S330 in FIG. 10: YES), the image processing A is executed. Characters are less likely to include the color difference colors described above than drawings and photographs. For this reason, in this case, the possibility that the target print direction is determined in the opposite direction to the immediately preceding print direction is relatively high. Image processing A capable of generating partial print data is executed. As a result, more appropriate image processing can be executed according to the type of image data corresponding to the print image OI.

F. Modification (1) At S105 of the image processing A (FIG. 5), the target pixel data is obtained in the order shown in FIG. For example, when the dither method is employed in the halftone processing in S130 of FIG. 5, the target pixel data may be acquired in the order shown in FIG. 6B in S105 of the image processing A. In this case, the time required to determine the target printing direction can be reduced. Further, when the dither method is employed in the halftone processing of S130 of FIG. 5, the processing of S195 of FIG. 5 can be omitted.

(2) At S105B of the image processing B and C (FIGS. 7 and 8) and S205 of the image processing D (FIG. 9), the target pixel data is obtained in the order shown in FIG. 6B. Instead, in these image processings B to D, target pixel data may be obtained in the order shown in FIG.

(3) The processing of S158B of the image processing B (FIG. 7) may be omitted. In this case, in S160B in FIG. 7, the color conversion processing is executed again for all the pixel data for which the color conversion processing has been executed in S125 in FIG.

(4) In the image processing C (FIG. 8), after the color conversion processing has been performed on all the target partial image data, that is, after S180 or S185, the nozzle NZ corresponding to the halftone processing (S186B) is determined. (S188B) are executed. Alternatively, in FIG. 8, after each of S120, S125C, and S127C, the halftone processing and the determination of the corresponding nozzle NZ may be performed for each pixel.

(5) Various methods can be used to determine whether or not the main object of the print image OI is a character in S330 of FIG. 10 of the fifth embodiment. For example, the CPU 310 specifies a main object of the print image OI by analyzing image data to be used for printing, and determines whether or not the main object of the print image OI is a character based on the specification result. You may decide. The CPU 310 may further determine whether or not the main object is a character by making an estimation based on a printing condition specified by a printing instruction from the user. For example, when the specified print mode is the image quality emphasis mode, the main object is determined to be a drawing or a photograph. When the specified print mode is the speed emphasis mode, the main object is a text or a photo. May be determined. When the paper used for printing is glossy paper, the main object is determined to be a drawing or a photograph, and when the paper used for printing is plain paper, the main object is determined to be text. Is also good. Further, the user may input at the time of printing whether the main object is a character or a non-character, and the CPU 310 may determine whether the main object is a character based on the input.

  For example, whether or not the main object is a character may be determined for each partial image. In this case, for example, the image processing to be executed may be switched for each partial image.

(6) In the fifth embodiment (FIG. 10), the determination processing (S310 to S345) for selecting the image processing to be executed is an example, and is not limited to this. For example, when it is assumed that a device having no multi-thread processing function performs image processing, the determination in S310 may be omitted. Also, the determination in S320 may be omitted. For example, when S310 and S320 are omitted, for example, the CPU 310 first executes the determination of S330 in FIG. 5, and thereafter performs the determination as shown in the flowchart of FIG.

  In FIG. 10, the image processing to be executed is selected from the three image processings A, C, and D, but is not limited thereto. For example, the image processing to be executed may be selected from the two image processings A and C. For example, when there is no unprocessed print job in the printer 200 and the main object of the print image OI is a character, the image processing A may be selected, and in other cases, the image processing C may be selected. . In S350 of FIG. 10, image processing B of FIG. 7 may be selected instead of image processing A.

(7) In S205 of the image processing D in FIG. 9, the CPU 310 obtains only a part of the pixel data among the plurality of pixel data corresponding to the attention determination area as the attention pixel data. Instead, the CPU 310 may acquire all the pixel data corresponding to the attention determination area as the attention pixel.

  Further, the CPU 310 generates reduced partial image data obtained by reducing the target partial image data using a predetermined algorithm (for example, the nearest neighbor method or bilinear method), and acquires target pixel data from the reduced partial image data. good. In this case, the processing time required for determining the target printing direction can be reduced by reducing the number of pixel data to be acquired.

(9) In the image processings A to D, the specific condition for determining the target print direction to the immediately preceding print direction is that the evaluation value EV of at least one determination area BL is equal to or larger than the threshold value THv. Not limited to For example, every time the CPU 310 acquires the target pixel data, the CPU 310 determines whether the target pixel data (RGB values) indicates a color difference generation color having an RGB value in a predetermined range, and indicates the color difference generation color. In this case, the number of color difference generating color pixels is counted up. Then, when the number of color difference generating color pixels reaches a predetermined threshold value, the CPU 310 determines the target printing direction to be the immediately preceding printing direction, and the number of color difference generating color pixels does not reach the predetermined threshold value. When the acquisition of is completed, the target print direction may be determined to be the reverse direction of the immediately preceding print direction.

  Also, whether or not to determine the target print direction as the immediately preceding print direction may always be determined using all pixel data included in the target partial image data. For example, when an object including a specific color pixel is arranged across both the target partial image and the partial image printed in the previous partial print, the CPU 310 changes the print direction of the target partial print to The printing direction of the immediately preceding partial printing may be determined. The arrangement position of the object in the image can be specified using, for example, a known object recognition process. If there is a solid-colored area at the boundary between the target partial image and the partial image printed by the previous partial printing, the color difference between the reciprocating movements tends to be conspicuous. For this reason, when there is the solid-colored area, the printing direction of the target partial printing may be determined to be the printing direction of the immediately preceding partial printing. In these cases, for example, the process of determining the target print direction and the first generation process are started in parallel using the multi-thread processing function. Then, similarly to the image processes A and B, the first generation process is interrupted after the target print direction is determined to be the immediately preceding print direction, the second generation process is started, and the target print direction is reversed from the immediately preceding print direction. When the direction is determined, the first generation processing is completed, and the second generation processing is not started. Alternatively, the process of determining the target print direction, the first generation process, and the second generation process are started in parallel using the multi-thread processing function. Then, similarly to the image processing C, when the target print direction is determined to be the immediately preceding print direction, the first generation processing is interrupted, the second generation processing is completed, and the target print direction is set to a direction opposite to the immediately preceding print direction. Is determined, the first generation processing is completed, and the second generation processing is interrupted.

(10) The arrangement positions of the nozzle rows of the print head 110 need not be in the order of the nozzle rows NC, NM, NY, and NK from the upstream side in the X direction in FIG. May be adopted. If a color difference occurs due to different printing directions, the nozzle rows may be arranged symmetrically with respect to the printing direction. For example, seven nozzle rows may be arranged in the order of NC, NM, NY, NK, NY, NM, and NC.

(11) In each image processing of the above embodiment, a partial image corresponding to one partial print is processed as one target partial image. Instead of this, for example, a partial image corresponding to a plurality of partial printings may be processed as one target partial image. For example, when processing a partial image corresponding to three partial printings as one target partial image, for example, in the first generation processing, the printing direction of each of the three partial printings is the immediately preceding partial printing. The color conversion process is executed by using different profiles so as to be in the opposite direction. That is, in the first generation process, three partial prints are printed in the forward pass, return pass, and forward pass, or three partial prints are printed in the return pass, forward pass, and return pass. First partial print data is generated. Further, for example, in the second generation processing, the color conversion processing is executed such that the printing directions of the three partial printings are the same as the previous partial printing. That is, in the second generation processing, three pieces of second partial print data are generated such that three partial prints are printed in forward printing or in return printing. If the target print direction is determined to be opposite to the immediately preceding print direction, three partial prints are performed bidirectionally using the three first partial print data, and the target print direction is set to the immediately preceding print direction. If it is determined in the direction, three partial prints are performed in one direction using three pieces of second partial image data.

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

(13) In the printing mechanism 100 of the above embodiment, the transport unit 140 transports the paper M, thereby moving the paper M relative to the print head 110 in the transport direction. Alternatively, the paper M may be moved relative to the print head 110 in the transport direction by moving the print head 110 in a direction opposite to the transport direction with respect to the fixed paper M.

(14) In each of the above embodiments, the device that executes the image processing A to D is the terminal device 300. Instead, the CPU 210 of the printer 200 may execute the image processing A to D as an image processing device. In this case, the CPU 210 that functions as an image processing apparatus stores the print data and the direction information in, for example, the nonvolatile storage device 220 or the volatile storage device in S190 of FIGS. 5, 7, and 8 and S270 of FIG. The data is output to a predetermined memory area of the device 230. The printing mechanism 100 of the printer 200 executes partial printing according to the print data and the direction information output to the memory area.

  As understood from the above description, in each of the above embodiments, the terminal device 300 is an example of an image processing device, and the printer 200 is an example of a print execution unit. In this modification, the CPU 210 of the printer 200 is an example of an image processing device, and the printing mechanism 100 of the printer 200 is an example of a print execution unit.

  The apparatus that executes the image processing A to D may be, for example, a server that obtains image data from a printer or a terminal device and generates a print job using the image data. Such a server may be a plurality of computers that can communicate with each other via a network. In this case, the entirety of the plurality of computers that can communicate with each other via the network is an example of the image processing apparatus.

(15) In each of the above embodiments, part of the configuration realized by hardware may be replaced with software, and conversely, part or all of the configuration realized by software may be replaced with hardware. You may do so. For example, when the image processing of FIG. 5 is executed in the printer 200, the color conversion processing and the halftone processing are realized by, for example, a dedicated hardware circuit (for example, an ASIC) that operates according to an instruction of the CPU 210 of the printer 200. You may.

  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.

    Reference numeral 100: printing mechanism, 110: print head, 111: nozzle forming surface, 120: head driving unit, 130: main scanning unit, 133: carriage, 134: sliding axis, 140: transport unit, 141: downstream roller pair, 142 .., Upstream roller pair, 145... Paper stand, 200... Printer, 210... CPU, 220... Nonvolatile storage device, 230... Volatile storage device, 231. Unit, 290 print execution unit, 300 terminal device, 310 CPU, 320 nonvolatile storage device, 330 volatile storage device, 331 buffer area, 360 operation unit, 370 display unit, 380 communication unit , 1000: printing system, PF1: outbound profile, PF2: return profile, PG1: computer program, PG2: compilation Over data program

Claims (9)

A print head having a first type of nozzle that discharges a first type of ink and a second type of nozzle that discharges a second type of ink at a position different from the first type of nozzle in the main scanning direction. A main scanning unit that performs a main scan that moves the print head along the main scanning direction with respect to a print medium, and the sub scanning direction that intersects the main scanning direction with respect to the print head. A sub-scanning unit that performs a sub-scan to move a print medium, and a print execution unit that performs partial printing that forms dots on the print medium by the print head while performing the main scan; and Performing printing by executing a plurality of times, an image processing apparatus for the print execution unit,
A color conversion profile for the forward path for the partial printing in the forward direction along the main scanning direction and a color conversion profile for the backward path for the partial printing in the backward direction along the main scanning direction are stored. In the storage unit, wherein the color conversion profile for the forward path and the color conversion profile for the return path include a plurality of colors including a first type of color value and the first type of ink and the second type of ink. A profile for converting into a second type of color value including a component value corresponding to the type of ink, and is obtained by converting the specific first type of color value using the color conversion profile for the outward path. The color of the image printed in the partial printing in the forward direction based on the second type color value and the specific first type color value are converted using the color conversion profile for the return path. Based on the second type of color value obtained The color of the image to be printed by the partial printing of the serial in the backward direction are adjusted such approaches, and the storage unit,
A first generating process including a first color conversion process is performed on target partial image data corresponding to a target partial image printed by the partial printing to be processed to generate first partial print data. 1, wherein the first color conversion process is performed in a direction opposite to a printing direction of the preceding partial printing, of the color conversion profile for the forward path and the color conversion profile for the return path. The first generation unit, which is executed using a profile corresponding to a first direction;
A second generation unit that executes a second generation process including a second color conversion process on the target partial image data to generate second partial print data, wherein the second color conversion process is performed. Executing the second generation using the profile corresponding to the second direction, which is the printing direction of the previous partial printing, of the color conversion profile for the forward pass and the color conversion profile for the return pass. Department and
A print direction determining unit that determines the target print direction, which is the print direction of the partial print to be processed, using the target partial image data, to one of the forward direction and the return direction; It is determined that a difference in color between the target partial image printed using the first partial print data and the target partial image printed using the second partial print data is less than a reference. The printing direction is determined to be the first direction, and if it is determined that the color difference is greater than or equal to the reference, the printing direction is determined to be the second direction. A decision unit,
When the target print direction is determined to be the first direction, the first partial print data is output to the print execution unit in order to perform the partial print of the processing target in the first direction, and An output unit configured to output the second partial print data to the print execution unit to cause the partial print to be performed in the first direction when a print direction is determined to be the second direction;
An image processing apparatus comprising: The image processing device according to claim 1,
The first generation unit starts the first generation process from a point in time when the target print direction is undetermined,
The image processing apparatus, wherein the second generation unit starts the second generation process from a point in time when the target print direction is not determined. The image processing device according to claim 2,
The first generator includes:
Interrupting the first generation processing at the time when the target printing direction is determined to be the second direction;
Completing the first generation processing when the target print direction is determined to be the first direction;
The second generation unit includes:
Interrupting the second generation processing at the time when the target printing direction is determined to be the first direction;
An image processing apparatus that completes the second generation processing when the target printing direction is determined to be the second direction. The image processing apparatus according to claim 3, wherein
The printing direction determination unit,
A plurality of determination areas are set in the noted partial image,
Of the noted partial image data, using area data corresponding to the determination area, determine whether the determination area satisfies a specific condition,
An image processing apparatus, wherein when the at least one determination area satisfies the specific condition, the target print direction is determined to be a specific one of the first direction and the second direction. The image processing apparatus according to claim 1, further comprising:
A capacity acquisition unit that acquires a capacity of a memory available for the first generation processing and the second generation processing;
When the available memory capacity is equal to or larger than a reference, a first process for starting the first generation process and the second generation process is executed from a point in time when the target print direction is not determined. And
When the available memory capacity is less than a reference, after the target printing direction is determined, the determined target printing direction is selected from the first generation processing and the second generation processing. An image processing apparatus in which a second process for starting a process corresponding to the above is performed. The image processing apparatus according to claim 1,
If multi-thread processing is possible, the first generation processing and the second generation processing are started in parallel using the multi-thread processing from the point in time when the target print direction has not been determined. One of a first process and a second process of starting the process corresponding to the target print direction of the first generation process and the second generation process after determining the target print direction. Is performed,
When the multi-thread process is not possible, at the time when the target print direction is undecided, the first generation process is started, and the third process is performed without starting the second generation process,
The second process is a process of determining a print direction of the next partial print, a process corresponding to the determined target print direction of the first generation process and the second generation process, The image processing apparatus starts in parallel using the multi-thread processing. The image processing device according to claim 1, further comprising:
The print execution unit includes a determination unit that determines the presence or absence of generated partial print data for partial printing that has not been performed,
When there is the generated partial print data, a first process for starting the first generation process and the second generation process from a point in time when the target print direction has not been determined; , A second process of starting the process corresponding to the target printing direction of the first generation process and the second generation process after the determination is performed, and
In a case where the generated partial print data does not exist, a third process in which the first generation process is started and the second generation process is not started at the time when the target print direction is undetermined, is executed. Image processing device. The image processing apparatus according to claim 1, further comprising:
Including the noted partial image data, comprising a specification unit that specifies the type of image data corresponding to the image to be printed,
When the image data is specified as the first type of data in which a main object is a drawing or a photograph, the first generation processing and the second generation processing are performed from a point in time when the target print direction is not determined. A second process that starts the process corresponding to the target printing direction of the first generation process and the second generation process after determining the target printing direction. Processing, and any one of the processing is executed,
When the image data is specified as the second type of data in which the main object is a character, the first generation processing is started at the time when the target print direction is undecided, and the second generation processing is started. An image processing apparatus in which a third process that does not start the generation process of the image is executed. A print head having a first type of nozzle that discharges a first type of ink and a second type of nozzle that discharges a second type of ink at a position different from the first type of nozzle in the main scanning direction. A main scanning unit that performs a main scan that moves the print head along the main scanning direction with respect to a print medium, and the sub scanning direction that intersects the main scanning direction with respect to the print head. A sub-scanning unit that performs a sub-scan to move a print medium, and a print execution unit that performs partial printing that forms dots on the print medium by the print head while performing the main scan; and Performing printing by executing a plurality of times, a computer program for the print execution unit,
A color conversion profile for the forward path for the partial printing in the forward direction along the main scanning direction and a color conversion profile for the backward path for the partial printing in the backward direction along the main scanning direction are stored. In the storage unit, wherein the color conversion profile for the forward path and the color conversion profile for the return path include a plurality of colors including a first type of color value and the first type of ink and the second type of ink. A profile for converting into a second type of color value including a component value corresponding to the type of ink, and is obtained by converting the specific first type of color value using the color conversion profile for the outward path. The color of the image printed in the partial printing in the forward direction based on the second type color value and the specific first type color value are converted using the color conversion profile for the return path. Based on the second type of color value obtained The color of the image to be printed by the partial printing of the serial in the backward direction are adjusted such approaches, and the storage unit,
A first generating process including a first color conversion process is performed on target partial image data corresponding to a target partial image printed by the partial printing to be processed to generate first partial print data. 1, wherein the first color conversion process is performed in a direction opposite to a printing direction of the preceding partial printing, of the color conversion profile for the forward path and the color conversion profile for the return path. The first generation unit, which is executed using a profile corresponding to a first direction;
A second generation unit that executes a second generation process including a second color conversion process on the target partial image data to generate second partial print data, wherein the second color conversion process is performed. Is executed using a profile corresponding to a second direction, which is a printing direction of the preceding partial printing, out of the color conversion profile for the forward pass and the color conversion profile for the return pass. Department and
A print direction determining unit that determines the target print direction, which is the print direction of the partial print to be processed, using the target partial image data, to one of the forward direction and the return direction; It is determined that a difference in color between the target partial image printed using the first partial print data and the target partial image printed using the second partial print data is less than a reference. The printing direction is determined to be the first direction, and if it is determined that the color difference is greater than or equal to the reference, the printing direction is determined to be the second direction. A decision unit,
When the target print direction is determined to be the first direction, the first partial print data is output to the print execution unit in order to perform the partial print of the processing target in the first direction, and An output unit configured to output the second partial print data to the print execution unit to cause the partial print to be performed in the first direction when a print direction is determined to be the second direction;
A computer program that causes a computer to realize

Images