JP5644159B2 - Printing apparatus, printing apparatus control method, and computer program - Google Patents

Description

  The present invention relates to printing that forms an image on a printing medium by ejecting ink.

  2. Description of the Related Art In recent years, printing apparatuses that print images by ejecting ink from nozzles provided in a print head while performing main scanning that reciprocates the print head to form ink dots on a print medium have become widespread. In such a printing apparatus, an achromatic color nozzle row that discharges achromatic color ink (for example, black ink) and a chromatic color nozzle row that discharges chromatic color ink (for example, cyan ink, magenta ink, and yellow ink) are used. A technique for forming a color region including a chromatic color in a print image and forming a monochrome region not including a chromatic color in the print image using only the achromatic color nozzle array is disclosed (for example, see Patent Document 1).

JP 2006-231930 A

  The conventional technology described above has room for improvement in terms of both improving the printing image quality and suppressing the increase in time required for the printing process. In particular, in the above-described conventional technique, the printing image quality is improved by suppressing the positional deviation along the main scanning direction of a line substantially parallel to the conveyance direction (sub-scanning direction) of the printing medium formed using the achromatic ink. In addition, there is room for improvement in terms of coexistence of the increase in time required for the printing process.

  SUMMARY An advantage of some aspects of the invention is to solve the above-described problem and perform printing while suppressing an increase in time required for printing processing when performing printing processing for forming an image on a printing medium by ejecting ink. The purpose is to improve image quality.

In order to solve at least a part of the above problems, the present invention can be realized as the following forms or application examples. One aspect of the present invention is a printing apparatus, which includes a chromatic color nozzle array configured by K (K is an integer of 2 or more) nozzles that discharge chromatic color inks arranged in the first direction. And an achromatic color nozzle array composed of (n · K) (n is an integer equal to or greater than 2) nozzles that discharge achromatic ink aligned along the first direction. A plurality of nozzle rows arranged side by side along a second direction that intersects the direction of the ink, and a moving mechanism that reciprocally moves the plurality of nozzle rows relative to the print medium along the second direction. A transport mechanism that relatively transports the print medium along the first direction with respect to the plurality of nozzle rows, and a movement mechanism that moves the plurality of nozzle rows in the forward and backward directions. Image forming operation for ejecting ink to the plurality of nozzle rows while performing And a control unit that forms an image on the print medium by repeating the transport operation of transporting the print medium to the transport mechanism, and the control unit includes the chromatic color in the image in the color region including the chromatic color. In the image forming operation of m times (m is an integer of 2 or more and n or less) in which the movement direction of the plurality of nozzle rows is alternately switched between the forward direction and the backward direction, the movement direction of the plurality of nozzle rows is the forward direction. The image forming operation is performed once and only the chromatic color nozzle row is used in a specific direction which is one of the reverse direction and the chromatic color nozzle row and the achromatic color nozzle row. A region having a predetermined width along the first direction of the image is formed by the m image forming operations including (m−1) times of the image forming operations, and the image does not include a chromatic color. In the monochrome area The region of the predetermined width of the image is formed by one image forming operation using only the achromatic color nozzle row, and the specific direction is the same for all the color regions in the image. And a printing apparatus for forming the image. In addition, the present invention can be realized in the following forms.

Application Example 1 A printing apparatus,
A chromatic color nozzle array composed of K (K is an integer of 2 or more) nozzles that discharge chromatic color inks aligned along the first direction, and an achromatic color aligned along the first direction An achromatic color nozzle array composed of (n · K) (n is an integer of 2 or more) nozzles that eject ink, and arranged along a second direction that intersects the first direction. A plurality of nozzle rows arranged in
A moving mechanism for reciprocally moving the plurality of nozzle rows relative to the print medium along the second direction;
A transport mechanism that transports the print medium relative to the plurality of nozzle rows along the first direction;
An image forming operation for causing the plurality of nozzle rows to eject ink while causing the moving mechanism to move the plurality of nozzle rows in the forward and backward directions; and a transport operation for causing the transport mechanism to transport the print medium. And a controller that forms an image on the print medium by repeating
In the color region including the chromatic color in the image, the control unit performs m times (m is an integer of 2 to n) in which the movement direction of the plurality of nozzle rows is alternately switched between the forward direction and the backward direction. In the forming operation, the moving direction of the plurality of nozzle rows is a specific direction that is one of the forward direction and the backward direction, and both the chromatic color nozzle row and the achromatic color nozzle row are used. Along the first direction of the image by m image forming operations including one image forming operation and (m-1) image forming operations in which only the chromatic color nozzle row is used. In the monochrome area that does not include a chromatic color in the image, the predetermined width area of the image is formed by one image forming operation in which only the achromatic color nozzle row is used. , Printing device.

  In this printing apparatus, the image forming operation in which the achromatic nozzle row is used in the color region is all in the same direction. Therefore, the ruled line substantially parallel to the first direction formed using the achromatic ink is used. Occurrence of misalignment along the second direction can be suppressed, and the print image quality can be improved. Further, in this printing apparatus, the number of nozzles constituting the achromatic color nozzle row is n times the number of nozzles constituting the chromatic color nozzle row, and in the color region, the chromatic color nozzle row and the achromatic color nozzle row A region having a predetermined width along the first direction of the image is formed by one image forming operation in which both are used and (m−1) image forming operations in which only the chromatic color nozzle row is used. Therefore, it is possible to suppress an increase in the time required for the printing process while setting the direction of the image forming operation in which the achromatic nozzle row is used to be the same direction. Therefore, in this printing apparatus, it is possible to improve the print image quality while suppressing an increase in time required for the printing process.

[Application Example 2] The printing apparatus according to Application Example 1,
The control unit performs the first image forming operation in which the moving direction of the plurality of nozzle rows is the specific direction among the m image forming operations, the chromatic color nozzle row and the achromatic color nozzle row. And a printing apparatus in which the image forming operation is performed once.

  In this printing apparatus, an image in which both the chromatic color nozzle row and the achromatic color nozzle row are used for the first image forming operation in which the movement direction of the plurality of nozzle rows is a specific direction among the m times of image forming operations. Since this is a forming operation, the achromatic nozzle array is used when the amount of ink on the print medium is relatively small and the deflection of the print medium is small, and the occurrence of ruled line position displacement can be effectively suppressed. it can.

[Application Example 3] The printing apparatus according to Application Example 1 or Application Example 2,
The printing apparatus, wherein the value of n is an even number.

  In this printing apparatus, it is possible to increase the speed by simplifying the processing.

  Note that the present invention can be realized in various modes. For example, the printing method and the printing apparatus, the control method and the control apparatus for the printing apparatus, the printing system, and the functions of these methods, the apparatus, and the system are realized. For example, a recording medium on which the computer program is recorded, a data signal that includes the computer program and is embodied in a carrier wave, and the like.

1 is a schematic configuration diagram of a printing system according to a first embodiment of the present invention. FIG. 2 is a block diagram illustrating a configuration of the ink jet printer 20 with a control circuit 40 as a center in the first embodiment. It is explanatory drawing which shows arrangement | positioning of the nozzle provided in the print head 28 of the inkjet printer 20 in 1st Example. It is explanatory drawing which shows an example of the recording method in the printing process by the inkjet printer 20 of 1st Example. It is explanatory drawing which shows another example of the recording method in the printing process by the inkjet printer 20 of 1st Example. It is explanatory drawing which shows the detailed example of the recording method in the printing process by the inkjet printer 20 of 1st Example. It is explanatory drawing which shows arrangement | positioning of the nozzle provided in the print head 28a of the inkjet printer 20 in 2nd Example. It is explanatory drawing which shows an example of the recording method in the printing process by the inkjet printer 20 of 2nd Example. It is explanatory drawing which shows an example of the recording method in the printing process by the inkjet printer 20 of 2nd Example. It is explanatory drawing which shows an example of the recording method in the printing process by the inkjet printer 20 of 3rd Example. It is explanatory drawing which shows an example of the recording method in the printing process by the inkjet printer 20 of 3rd Example. It is explanatory drawing which shows an example of the recording method in the printing process by the inkjet printer 20 of 4th Example.

Next, embodiments of the present invention will be described in the following order based on examples.
A. First embodiment:
A-1. Configuration of printing device:
A-2. Recording method:
B. Second embodiment:
C. Third embodiment:
D. Fourth embodiment:
E. Variations:

A. First embodiment:
A-1. Configuration of printing device:
FIG. 1 is a schematic configuration diagram of a printing system according to a first embodiment of the present invention. The printing system according to the first embodiment includes an inkjet printer 20 and a computer 88 that supplies a print signal PS to the inkjet printer 20. The ink jet printer 20 is connected to a computer 88 via a connector 56.

  The ink jet printer 20 includes a moving mechanism that performs main scanning for reciprocating the carriage 30 along a direction parallel to the axis of the platen 26, and a sheet P as a printing medium in a direction (sub scanning direction) that intersects the main scanning direction. A transport mechanism that performs the sub-scan to be transported, a print head unit 60 mounted on the carriage 30, and a control circuit 40 that controls each part of the inkjet printer 20 are provided.

  The transport mechanism that transports the paper P includes a paper feed motor 22 and a gear train (not shown) that transmits the rotation of the paper feed motor 22 to a paper transport roller (not shown). The rotation of the paper feed motor 22 is transmitted to the paper transport roller, and the paper P is transported by the rotation of the paper transport roller. The moving mechanism for reciprocating the carriage 30 is endless between the carriage motor 24, the carriage motor 24, a sliding shaft 34 that is laid in parallel to the axis of the platen 26, and slidably holds the carriage 30. A pulley 38 that stretches the drive belt 36 and a position detection sensor 39 that detects the origin position of the carriage 30 are included. The rotation of the carriage motor 24 is transmitted to the carriage 30 via the drive belt 36, whereby the carriage 30 reciprocates along the sliding shaft 34. The direction parallel to the main scanning direction corresponds to the second direction in the present invention, and the direction parallel to the sub-scanning direction corresponds to the first direction in the present invention.

  FIG. 2 is a block diagram showing the configuration of the ink jet printer 20 centering on the control circuit 40 in the first embodiment. The control circuit 40 is configured as an arithmetic and logic circuit including a CPU 41, a ROM 43, a RAM 44, and a character generator (CG) 45 that stores a dot matrix of characters. The control circuit 40 further includes an I / F dedicated circuit 50 that is an interface with an external motor, a head drive circuit 52 that is connected to the I / F dedicated circuit 50 and drives the print head unit 60, and paper feeding. And a motor drive circuit 54 that drives the motor 22 and the carriage motor 24. The I / F dedicated circuit 50 receives the print signal PS supplied from the computer 88 via the connector 56. The CPU 41 causes the control circuit 40 to function as a control unit that controls the inkjet printer 20 by executing a computer program stored in the ROM 42.

  The print head unit 60 includes a print head 28. The print head 28 includes a plurality of nozzle rows (described later) that eject ink, and an actuator circuit that operates a piezo element provided in each nozzle constituting each nozzle row. The actuator circuit is a part of the head drive circuit 52 and controls on / off of a drive signal supplied from a drive signal generation circuit (not shown) in the head drive circuit 52. That is, the actuator circuit latches dot data indicating ON (ink is ejected) or OFF (ink is not ejected) for each nozzle in accordance with the print signal PS supplied from the computer 88, and the drive signal is only for the ON nozzle. Is applied to the piezo element.

  FIG. 3 is an explanatory diagram showing the arrangement of nozzles provided in the print head 28 of the inkjet printer 20 in the first embodiment. The inkjet printer 20 of the first embodiment performs printing using four colors of ink of black (K), cyan (C), magenta (M), and yellow (Y). Therefore, a plurality of nozzle rows corresponding to four ink colors are arranged in the print head 28 along the main scanning direction. Specifically, for each of the three chromatic color inks (cyan ink, yellow ink, and magenta ink), the print head 28 includes one nozzle row composed of 152 nozzles arranged in the sub-scanning direction. (Indicated as “C”, “Y”, and “M” in FIG. 3 respectively), the achromatic ink (black ink) is composed of 152 nozzles arranged in the sub-scanning direction. Two nozzle rows are arranged (indicated as “K0” and “K1” in FIG. 3).

  As shown in FIG. 3, the nozzle pitch of each nozzle row is the same. Regarding the positions along the sub-scanning direction, the positions of the cyan nozzle row, the magenta nozzle row, and the one black nozzle row (K0) are the same, and the yellow nozzle row and the other black nozzle row (K1). This position is a position shifted by a half of the nozzle pitch from the positions of the cyan nozzle row, the magenta nozzle row, and the one black nozzle row (K0). The two black nozzle rows can be regarded as one nozzle row composed of 304 nozzles in a so-called staggered arrangement, as indicated by the nozzle numbers in parentheses in FIG. In this way, assuming that the number of nozzles constituting each nozzle row for chromatic colors is K, the number of nozzles constituting the nozzle row for black is (n · K) (where n = 2). That is, the number of nozzles constituting the black nozzle row is twice the number of nozzles constituting each chromatic color nozzle row. The nozzle pitch of the black nozzle row is twice as fine as the nozzle pitch of each chromatic color nozzle row.

  Thus, the two nozzle rows for black can be regarded as one nozzle row in a staggered arrangement. Further, in the example of FIG. 3, in each chromatic color nozzle row of the print head 28, the positions of the nozzles constituting the nozzle row along the main scanning direction are all the same (that is, linear). However, the chromatic color nozzle rows may be so-called staggered nozzle rows. That is, in this specification, “nozzle row” means a plurality of nozzles arranged side by side along the sub-scanning direction, and “a plurality of nozzles are arranged side by side along the sub-scanning direction”. Means that the positions of the plurality of nozzles along the sub-scanning direction are arranged so as to be different from each other regardless of the positions of the nozzles along the main scanning direction.

  A print head unit 60 having the print head 28 is mounted on the carriage 30. Therefore, the print head 28 is reciprocally moved relative to the print medium along the sliding shaft 34 (along the main scanning direction) by the carriage motor 24 (FIG. 1). Further, the paper P is transported to the print head 28 by the paper feed motor 22 in the paper feed direction (sub-scanning direction).

  In the ink jet printer 20 of the present embodiment having the above-described configuration, the control circuit 40 causes the print head unit 60 to eject ink while causing the carriage 30 having the print head unit 60 mounted on the moving mechanism to reciprocate. A printing process for forming an image on the paper P is performed by repeating the operation and the transporting operation for transporting the paper P to the transport mechanism. The ink jet printer 20 performs color conversion processing and halftone processing based on the print signal PS received from the computer 88, and generates dot data indicating ON / OFF of each nozzle in the print processing. Since these processes are well-known, description of the process contents is omitted.

A-2. Recording method:
FIG. 4 is an explanatory diagram illustrating an example of a recording method in the printing process performed by the inkjet printer 20 according to the first embodiment. FIG. 4 shows each image area when a print image is divided into a color area that is an image area that includes a chromatic color and a monochrome area that is an image area that does not include a chromatic color along the sub-scanning direction (paper feeding direction). The position along the sub-scanning direction of the nozzle row used in each pass for forming the.

  Here, “pass” means an operation of moving the print head 28 (FIG. 3) including each nozzle row in the forward or backward direction of the main scanning direction by the above-described moving mechanism. In FIG. 4, a path with the number “r” attached to the number of passes is a path for moving the print head 28 in the backward direction, and the other paths are paths for moving the print head 28 in the forward direction. The forward direction is a direction from a home position preset in the vicinity of one end of the movement path of the carriage 30 to the vicinity of the other end, and the backward direction is a direction opposite to the forward direction. Further, in each pass, when the “K” code is attached, the black nozzle row is used at the position along the sub-scanning direction of the rectangle attached with the “K” code, and the “Co” code is attached. If it is, the chromatic color nozzle row is used at a position along the sub-scanning direction of the rectangle with the “Co” symbol. In each pass, the black nozzle row is not used when the “K” symbol is not attached, and the chromatic nozzle row is not used when the “Co” symbol is not attached. Note that the black nozzle row or chromatic color nozzle row is used in each pass if the dot data corresponding to the pass contains data that should eject black ink or chromatic color ink. This means that the corresponding color ink is ejected from the nozzle row. Even when a black nozzle row or a chromatic color nozzle row is used in a certain pass, if there is no data to eject black ink or chromatic color ink in the dot data corresponding to that pass The corresponding color ink is not ejected from the corresponding nozzle row. Further, the pass involving the use of the black nozzle row or the chromatic color nozzle row corresponds to the above-described image forming operation. As will be described later, the pass may be a pass (empty pass) that does not involve the use of both the black nozzle row and the chromatic color nozzle row.

  In the example of FIG. 4, the print image is configured in the order of a color area, a monochrome area, a color area, a monochrome area,. Therefore, in the printing process, first, an image of a color area is formed. In the first color area, the first pass in the forward direction in which both the black nozzle row and the chromatic color nozzle row are used, and the second pass in the backward direction in which only the chromatic color nozzle row is used, An image (hereinafter also referred to as “unit band”) having a predetermined width along the scanning direction (a width corresponding to the length of each nozzle row) is formed. In the following, a path in which both the black nozzle row and the chromatic nozzle row are used is also referred to as a “black / chromatic color combined pass”, and a pass in which only the chromatic nozzle row is used is referred to as “chromatic color only”. Also referred to as “pass”, a pass in which only the black nozzle row is used is also referred to as “black only pass”. Subsequently, adjacent to the unit band formed by the first pass and the second pass by the third pass, which is a black / chromatic color combination pass in the forward direction, and the fourth pass, which is a pass only in the chromatic color in the backward direction. The next unit band is formed. As described above, in the color area, the forward and backward passes are alternately repeated, and one black / chromatic color combined pass in a specific direction (for example, the forward direction) and the reverse direction of the specific direction (for example, the backward direction). The recording method in which a unit band is formed by a total of two passes (image forming operation) including a single chromatic color pass). In other words, in the color area, the directions of the passes in which the black nozzle rows are used are all the same direction (specific direction). As will be described later, a transport operation (paper feed) for one main scanning line is performed between two passes forming a unit band.

  Further, as shown in FIG. 4 as the fifth pass and the sixth pass, in this embodiment, in addition to the case where the entire unit band to be formed is located in the color region, a part of the unit band to be formed is colored. The recording method in the color area described above is also used when the remaining part is located in the monochrome area. In this case, among the nozzles constituting the chromatic color nozzle row, the nozzles located in the monochrome area are masked and not used. When the entire unit band to be formed is located in the monochrome area, the following recording method in the monochrome area is adopted.

  In the first monochrome area in the example of FIG. 4, first, a unit band is formed by the seventh pass, which is a forward only black pass. Next, the next unit band adjacent to the unit band formed by the seventh pass is formed by the eighth pass, which is the black-only pass in the backward direction. In this way, in the monochrome area, a recording method is adopted in which only forward and backward black passes are alternately repeated, and unit bands are formed by a single black pass (image forming operation). In the subsequent ninth pass and tenth pass, a part of the unit band to be formed is located in the color area, and printing is performed according to the recording method in the color area described above.

  FIG. 5 is an explanatory diagram illustrating another example of the recording method in the printing process performed by the inkjet printer 20 according to the first embodiment. In the example of FIG. 5, the recording method from the first pass to the seventh pass is the same as the example of FIG. In the example of FIG. 5, when the forward seventh pass is completed, a part of the unit band to be formed in the next backward eighth pass is located in the color area. Therefore, according to the recording method in the color area described above, the next eighth pass in the backward direction is a black / chromatic color combined pass. However, in this embodiment, the unit band immediately before the boundary with the color area in the monochrome area is the path in the same direction as the specific direction (the direction of the black / chromatic color combined path) described above when forming the other color areas. In this case, the next pass of the pass for forming the immediately preceding unit band is in a direction opposite to the specific direction without using any of the black nozzle row and the chromatic color nozzle row. It is assumed that the color area is formed by the empty pass and the subsequent passes. In the example of FIG. 5, the unit band immediately before the boundary with the color area in the monochrome area is formed by the seventh path that is the same direction as the specific direction (that is, the forward direction) in the first color area. The eighth pass, which is a path of the second, is an empty path in the reverse direction (reverse direction) to the specific direction (that is, a path that moves to the home position HP), and the subsequent ninth pass is a combination of black and chromatic colors in the same direction as the specific direction It is a pass. In this way, the direction of the black / chromatic color combination pass is unified in the same direction in all color regions in the printed image.

  FIG. 6 is an explanatory diagram showing a detailed example of a recording method in the printing process by the ink jet printer 20 of the first embodiment. FIG. 6 shows the positions along the sub-scanning direction of the nozzle rows used in each pass for forming each image region (color region and monochrome region) of the print image, as in FIGS. 4 and 5. ing. In FIG. 6, the positions of the nozzles constituting each nozzle row are indicated by numerals. Since the positions of the cyan nozzle row (C) and the magenta nozzle row (M) along the sub-scanning direction are the same, FIG. 6 shows the position of only one of the cyan nozzle row and the magenta nozzle row. ing. In addition, nozzles marked with an X mark superimposed on the numbers indicating the nozzle positions represent nozzles that are not used in the pass.

  In the example of FIG. 6, for ease of explanation, each of the chromatic color nozzle arrays is composed of 7 nozzles, and the black nozzle array is composed of 14 nozzles. That is, if the number of nozzles constituting each nozzle row for chromatic color is K, the number of nozzles constituting the nozzle row for black is (n · K) (where n = 2). In the example of FIG. 6, in the printed image, the area from the first main scanning line (first raster) to the 39th main scanning line is a color area, and from the 40th main scanning line to the 67th main scanning line. The area is a monochrome area, and the area after the 68th main scan line is a color area.

  As shown in FIG. 6, in the first color region, the forward black / chromatic color combined pass is executed as the first pass, and after the minute transport operation Sc for one main scanning line is performed, Only the chromatic color in the backward direction is executed. In the second pass, a chromatic color raster is newly formed between the chromatic color rasters formed in the first pass. Therefore, the formation of the first unit band is completed by the first pass and the second pass. Next, the main transport operation Sm for 13 main scan lines is performed, the forward black / chromatic color combined pass is executed as the third pass, and the micro transport operation Sc for one main scan line is performed. Only the chromatic color in the backward direction is executed as the fourth pass, and the formation of the next unit band is completed by these two passes.

  In the subsequent fifth pass and sixth pass, a part of the unit band to be formed is located in the color area and the remaining part is located in the monochrome area. Is formed. At this time, among the nozzles constituting the chromatic color nozzle row, the nozzles located in the monochrome area are masked and not used.

  In the first monochrome area, only the forward black pass is executed as the seventh pass. With this one pass, the formation of the first unit band in the monochrome area is completed. In the example of FIG. 6, when the main transport operation Sm for 13 main scanning lines is performed after the seventh pass, a part of the unit band to be formed in the next pass is located in the color area. Therefore, in the example of FIG. 6, the unit band immediately before the boundary with the color area in the monochrome area is in the same direction as the above-described specific direction (the direction of the black / chromatic color combined pass) when forming the other color areas. It is formed by the pass. Therefore, the eighth pass, which is the next pass, is a backward pass that does not involve the use of any nozzle row. Thereafter, after the main transport operation Sm for 13 main scanning lines is performed, the second color area is formed by the ninth pass and thereafter. In the example of FIG. 6, the main transport operation Sm is performed after the eighth pass that is an empty pass, but the main transport operation Sm is performed after the seventh pass, and then the eighth pass that is an empty pass. May be executed.

  As described above, in the inkjet printer 20 of the present embodiment, assuming that the number of nozzles constituting each chromatic color nozzle row is K, the number of nozzles constituting the black nozzle row is (n · K) ( However, n = 2). In the printing process by the inkjet printer 20 of the present embodiment, in the color region, the forward direction and the backward direction pass are alternately repeated, and one black / chromatic color combined pass in the specific direction (for example, the forward direction) and the specific direction are performed. A recording method in which a unit band is formed by a total of two passes (image forming operation) including only one chromatic color pass in the reverse direction (for example, the backward direction) is used. That is, in each color region, the pass directions in which the black nozzle rows are used are all the same direction (specific direction). In a certain color area, when the direction of the pass in which the black nozzle row is used includes both the forward direction and the backward direction, the main scanning of the ruled line formed substantially parallel to the sub-scanning direction formed using black ink There is a possibility that a positional deviation along the direction (so-called Bi-d deviation) may occur. In the present embodiment, in all color areas, the directions of the paths in which the black nozzle rows are used are all unified in the same direction, so the occurrence of the ruled line misalignment can be suppressed, and the print image quality can be improved. be able to. In this embodiment, the number of nozzles constituting the black nozzle row is set to be twice the number of nozzles constituting each chromatic color nozzle row, and the unit band in the color region is a single black / chromatic color combined pass. Since only one chromatic color is formed with a pass, it is possible to suppress a decrease in printing speed while suppressing the occurrence of the ruled line position deviation described above. Further, in the present embodiment, in the monochrome area, a recording method is adopted in which passes only in the forward and backward blacks are alternately repeated and a unit band is formed by a single black pass. The printing speed can be improved. In addition, since the chromatic ink is not ejected in the monochrome area, the amount of ink per unit area of the print medium is relatively small compared to the color area, and the deflection of the print medium is small. Therefore, in the monochrome area, even if only the forward and backward black paths are used together, there is little risk of occurrence of the ruled line position deviation described above. From the above, in the inkjet printer 20 of the present embodiment, it is possible to improve the print image quality while suppressing an increase in the time required for the printing process.

  In the inkjet printer 20 of the present embodiment, the unit band immediately before the boundary with the color area in the monochrome area is the same as the specific direction (direction of the black / chromatic color combined pass) described above when forming the other color areas. When formed by a direction pass, the pass next to the pass for forming the immediately preceding unit band is an empty pass that does not involve the use of either the black nozzle row or the chromatic color nozzle row. The color area is formed by the next pass and after. For this reason, in this embodiment, the direction of the black / chromatic color combined pass is unified in the same direction in all the color regions in the printed image. Here, in the forward black / chromatic color combination pass and the backward black / chromatic color combination pass, the overlapping order of the black ink dots and the chromatic ink dots on the printing medium is reversed. Therefore, if the image area formed by the forward black / chromatic color combination pass and the image area formed by the backward black / chromatic color combination pass are mixed in the printed image, color unevenness may occur. is there. In this embodiment, the direction of the black and chromatic color combined pass is unified in the same direction in all the color areas in the printed image, so that the occurrence of color unevenness can be suppressed and the print image quality can be further improved. it can.

B. Second embodiment:
FIG. 7 is an explanatory diagram showing the arrangement of nozzles provided in the print head 28a of the inkjet printer 20 in the second embodiment. The nozzle arrangement of the print head 28a in the second embodiment is that four nozzle rows each comprising 152 nozzles are arranged for the black ink. The print head 28 in the first embodiment shown in FIG. This is different from the nozzle arrangement. That is, the print head 28a in the second embodiment is provided with black nozzle rows K2 and K3 in addition to the black nozzle rows K0 and K1 provided in the same manner as in the first embodiment.

  As shown in FIG. 7, the nozzle pitch of the black nozzle rows K2 and K3 is the same as the nozzle pitch of the black nozzle rows K0 and K1. Regarding the position along the sub-scanning direction, the position of the black nozzle row K2 is a position shifted by a quarter of the nozzle pitch from the position of the black nozzle row K0, and the position of the black nozzle row K3 is The position is shifted from the position of the black nozzle row K1 by a quarter of the nozzle pitch. Accordingly, the four black nozzle rows are arranged in the order of K0, K2, K1, and K3 while being shifted by a quarter of the nozzle pitch. The four black nozzle rows can be regarded as one nozzle row composed of 608 nozzles, as indicated by the nozzle numbers in parentheses in FIG. In this way, if the number of nozzles constituting each nozzle row for chromatic colors is K, the number of nozzles constituting the nozzle row for black is (n · K) (where n = 4). That is, the number of nozzles constituting the black nozzle row is four times the number of nozzles constituting each chromatic color nozzle row. The nozzle pitch of the black nozzle row is four times finer than the nozzle pitch of each chromatic color nozzle row.

  8 and 9 are explanatory diagrams illustrating an example of a recording method in the printing process by the ink jet printer 20 according to the second embodiment. 8 and 9, as in FIG. 6 showing the recording method in the first embodiment, nozzle rows used in each pass for forming each image area (color area and monochrome area) of the print image. The position along the sub-scanning direction is shown.

  In the example of FIGS. 8 and 9, for ease of explanation, each of the chromatic color nozzle arrays is composed of 7 nozzles, and the black nozzle array is composed of 28 nozzles. That is, if the number of nozzles constituting each nozzle row for chromatic color is K, the number of nozzles constituting the nozzle row for black is (n · K) (where n = 4). 8 and 9, in the printed image, the region from the first main scanning line (first raster) to the 38th main scanning line is a color region, and the 39th main scanning line to the 86th main scanning line. The area up to the line is a monochrome area, and the area after the 87th main scan line is a color area.

  As shown in FIG. 8, in the first color region, the forward black / chromatic color combined pass is executed as the first pass, and after the minute transport operation Sc for one main scanning line is performed, Only the chromatic color in the backward direction is executed. Further, after the minute conveyance operation Sc for one main scanning line is performed, only the chromatic color in the forward direction is executed as the third pass, and after the minute conveyance operation Sc for one main scanning line is performed, Only four chromatic colors in the backward direction are executed as four passes. In the second pass to the fourth pass, a chromatic color raster is newly formed between the chromatic color rasters formed in the first pass. The formation of the first unit band is completed by four passes from the first pass to the fourth pass.

  Next, the main transport operation Sm for 25 main scan lines is performed, the forward black / chromatic color combined pass is executed as the fifth pass, and the micro transport operation Sc for one main scan line is performed. Only the chromatic color in the backward direction is executed as the sixth pass, and only the chromatic color in the forward direction is executed as the seventh pass after the minute transport operation Sc for one main scanning line is performed. After the minute minute transport operation Sc is performed, only the chromatic color in the backward direction is executed as the eighth pass. The formation of the next unit band is completed by four passes from the fifth pass to the eighth pass. In addition, since a part of the unit band formed at this time is located in the monochrome area, the nozzle located in the monochrome area is not used because it is masked in each pass.

  In this way, in the color area, the forward and backward passes are alternately repeated, and one black / chromatic color combined pass in a specific direction (for example, the forward direction) and three passes in the forward or backward direction. A recording method in which a unit band is formed by a total of four passes (image forming operation) including only a chromatic color pass is adopted. In other words, in the color area, the directions of the passes in which the black nozzle rows are used are all the same direction (specific direction). In this embodiment, of the four passes performed for forming the unit band in the color region, the first specific direction pass is the black / chromatic color combined pass. For example, when the specific direction is the forward direction, the first specific rather than the third path that is the second specific direction path among the first to fourth paths performed for forming the first unit band is used. The first pass, which is a direction pass, is a black / chromatic color combined pass.

  In the first monochrome area, only the forward black pass is executed as the ninth pass (FIG. 9). With this one pass, the formation of the first unit band in the monochrome area is completed. In the second embodiment as well, in the monochrome area, a recording method is adopted in which passes only in the forward and backward black are alternately repeated and a unit band is formed by only one black pass.

  Also in the second embodiment, the unit band immediately before the boundary with the color area in the monochrome area is the same direction as the above-described specific direction (the direction of the combined black and chromatic color path) when forming the other color areas. In this case, the next pass after the pass for forming the immediately preceding unit band is an empty pass that does not involve the use of either the black nozzle row or the chromatic color nozzle row. The color area is formed after the first pass. In the example of FIG. 9, when the main transport operation Sm for 25 main scanning lines is performed after the ninth pass, a part of the unit band to be formed in the next pass is located in the color area, so monochrome The unit band immediately before the boundary with the color area in the area is formed by the path in the same direction as the above-described specific direction (direction of the combined black and chromatic color) when forming the other color areas. Accordingly, the tenth pass, which is the next pass, is a backward pass that does not involve the use of any nozzle row. Thereafter, after the main transport operation Sm for 25 main scanning lines is performed, the second color area is formed by the eleventh pass and thereafter. In the example of FIG. 9, the main transport operation Sm is performed after the tenth pass which is an empty pass, but the main transport operation Sm is performed after the ninth pass and then the tenth pass which is an empty pass. May be executed.

  As described above, in the inkjet printer 20 of the second embodiment, assuming that the number of nozzles constituting each chromatic color nozzle row is K, the number of nozzles constituting the black nozzle row is (n · K). (Where n = 4). In the printing process by the ink jet printer 20 of the second embodiment, in the color region, the forward and backward passes are alternately repeated, and one black / chromatic color combined pass and forward pass in a specific direction (for example, the forward direction). A recording method is adopted in which unit bands are formed by a total of four passes (image forming operation) including only three chromatic colors in the direction or backward direction. That is, in each color region, the pass directions in which the black nozzle rows are used are all the same direction (specific direction). Therefore, in the second embodiment, as in the first embodiment, the occurrence of ruled line misalignment can be suppressed, and the print image quality can be improved. In the second embodiment, the number of nozzles constituting the black nozzle row is set to be four times the number of nozzles constituting each chromatic color nozzle row, and the unit band is used once for the black / chromatic color combination pass in the color region. Since only three chromatic colors are formed with a pass, it is possible to suppress a decrease in printing speed while suppressing occurrence of ruled line position deviation. Further, in the second embodiment, in the monochrome area, a recording method is adopted in which passes only in the forward and backward blacks are alternately repeated and a unit band is formed by only one black pass. The printing speed can be improved in a monochrome area where the ink amount per area is relatively small and the risk of occurrence of ruled line position deviation is small. Therefore, the inkjet printer 20 of the second embodiment can improve the print image quality while suppressing an increase in the time required for the printing process as in the first embodiment.

  Also in the inkjet printer 20 of the second embodiment, when the unit band immediately before the boundary with the color area in the monochrome area is formed by a path in the same direction as the specific direction described above when forming the other color area. The next pass of the pass for forming the immediately preceding unit band is an empty pass that does not involve the use of either the black nozzle row or the chromatic color nozzle row, and the color region is formed by the next pass and thereafter. Therefore, the direction of the black and chromatic color combined pass is unified in the same direction in all color regions in the printed image, so that the occurrence of color unevenness can be suppressed and the print image quality can be further improved. .

  In the inkjet printer 20 of the second embodiment, the first specific direction (for example, the forward direction) of the four passes performed for forming the unit band in the color region is the black / chromatic color combined pass. It is said. When a unit band is formed by a plurality of passes, the amount of ink in the unit band region on the print medium increases each time the passes are overlapped, so that the deflection of the print medium in the unit band increases. In the second embodiment, since the first specific direction pass is a black / chromatic color combined pass, the black nozzle row is used when the deflection of the print medium is relatively small, and the occurrence of the ruled line position deviation is caused. It can be effectively suppressed.

C. Third embodiment:
10 and 11 are explanatory diagrams illustrating an example of a recording method in the printing process by the ink jet printer 20 according to the third embodiment. 10 and 11, similarly to FIG. 6 showing the recording method in the first embodiment, nozzle rows used in each pass for forming each image area (color area and monochrome area) of the print image. The position along the sub-scanning direction is shown.

  In the example of FIGS. 10 and 11, each of the chromatic color nozzle arrays is composed of 7 nozzles, and the black nozzle array is composed of 28 nozzles. That is, if the number of nozzles constituting each nozzle row for chromatic color is K, the number of nozzles constituting the nozzle row for black is (n · K) (where n = 4). In the example of FIGS. 10 and 11, in the print image, the region from the first main scanning line (first raster) to the 34th main scanning line is a color region, and the 35th main scanning line to the 86th main scanning line. The area up to the line is a monochrome area, and the area after the 87th main scan line is a color area.

  As shown in FIG. 10, in the first color area, the forward black / chromatic color combined pass is executed as the first pass, and after the minute transport operation Sc for two main scanning lines is performed, Only the chromatic color in the backward direction is executed. In the second pass, a chromatic color raster is newly formed between the chromatic color rasters formed in the first pass. The formation of the first unit band is completed by a total of two passes, the first pass and the second pass. In the unit band formed at this time, the resolution along the sub-scanning direction of the main scanning line formed by the black nozzle row is along the sub-scanning direction of the main scanning line formed by the chromatic color nozzle row. The resolution is twice as fine as the resolution.

  Next, the main transport operation Sm for 26 main scan lines is performed, the forward black / chromatic color combined pass is executed as the third pass, and the micro transport operation Sc for 2 main scan lines is performed. Only the chromatic color in the backward direction is executed as the fourth pass. The formation of the next unit band is completed by a total of two passes, the third pass and the fourth pass. In addition, since a part of the unit band formed at this time is located in the monochrome area, the nozzle located in the monochrome area is not used because it is masked in each pass.

  As described above, in the color area, the forward and backward passes are alternately repeated, and one black / chromatic color combined pass in a specific direction (for example, the forward direction) and the reverse direction of the specific direction (for example, the backward direction). The recording method in which a unit band is formed by a total of two passes (image forming operation) including a single chromatic color pass). In other words, in the color area, the directions of the passes in which the black nozzle rows are used are all the same direction (specific direction).

  Further, in the first monochrome area, only the forward black pass is executed as the fifth pass (FIG. 11). With this one pass, the formation of the first unit band in the monochrome area is completed. In the third embodiment as well, in the monochrome area, a recording method is employed in which passes only in the forward and backward black are alternately repeated and a unit band is formed by only one black pass.

  Also in the third embodiment, the unit band immediately before the boundary with the color area in the monochrome area is the same as the specific direction (direction of the black / chromatic color combined path) described above when forming the other color areas. In this case, the next pass after the pass for forming the immediately preceding unit band is an empty pass that does not involve the use of either the black nozzle row or the chromatic color nozzle row. The color area is formed after the first pass. In the example of FIG. 11, when the main transport operation Sm for 26 main scanning lines is performed after the fifth pass, a part of the unit band to be formed in the next pass is located in the color area, so monochrome The unit band immediately before the boundary with the color area in the area is formed by the path in the same direction as the above-described specific direction (direction of the combined black and chromatic color) when forming the other color areas. Accordingly, the sixth pass, which is the next pass, is a backward empty pass that does not involve the use of any nozzle row. Thereafter, after the main transport operation Sm for 26 main scan lines is performed, the second color area is formed by the seventh pass and thereafter. In the example of FIG. 11, the main transport operation Sm is performed after the sixth pass that is an empty pass, but the main transport operation Sm is performed after the fifth pass, and then the sixth pass that is an empty pass. May be executed.

As described above, in the inkjet printer 20 of the third embodiment, assuming that the number of nozzles constituting each chromatic color nozzle row is K, the number of nozzles constituting the black nozzle row is (n · K). (Where n = 4). In the printing process by the ink jet printer 20 of the third embodiment, in the color region, the forward and backward passes are alternately repeated, and a single black / chromatic color combined pass in the specific direction (for example, the forward direction) is specified. A recording method in which a unit band is formed by a total of two passes (image forming operation) including a single chromatic color pass in the reverse direction (for example, the backward direction) of the direction is adopted. That is, in each color region, the pass directions in which the black nozzle rows are used are all the same direction (specific direction). Therefore, in the third embodiment, as in the first embodiment, the occurrence of ruled line misalignment can be suppressed, and the print image quality can be improved. In the third embodiment, the number of nozzles constituting the black nozzle row is double the number of nozzles constituting each chromatic color nozzle row, and the unit band is used once in the color region for the combined black and chromatic color pass. Sub-scanning of the main scanning line formed by the chromatic color nozzle row with a resolution along the sub-scanning direction of the main scanning line formed by the black nozzle row. Since the resolution is twice as fine as the resolution along the direction, it is possible to suppress a decrease in printing speed while suppressing occurrence of ruled line position deviation.
Furthermore, in the third embodiment, in the monochrome area, a recording method is adopted in which passes only in the forward and backward black are alternately repeated and a unit band is formed by only one black pass. The printing speed can be improved even in a monochrome region in which the amount of ink per area is relatively small and the risk of occurrence of ruled line position deviation is small. Therefore, the inkjet printer 20 of the third embodiment can improve the print image quality while suppressing an increase in the time required for the printing process as in the first embodiment.

  Also in the inkjet printer 20 of the third embodiment, when the unit band immediately before the boundary with the color area in the monochrome area is formed by the path in the same direction as the specific direction described above when forming the other color area. The next pass of the pass for forming the immediately preceding unit band is an empty pass that does not involve the use of either the black nozzle row or the chromatic color nozzle row, and the color region is formed by the next pass and thereafter. Therefore, the direction of the black and chromatic color combined pass is unified in the same direction in all color regions in the printed image, so that the occurrence of color unevenness can be suppressed and the print image quality can be further improved. .

D. Fourth embodiment:
FIG. 12 is an explanatory diagram illustrating an example of a recording method in print processing by the inkjet printer 20 according to the fourth embodiment. FIG. 12 shows the sub-scanning direction of the nozzle row used in each pass for forming each image area (color area and monochrome area) of the print image, as in FIG. 4 showing the recording method of the first embodiment. The position along is shown. The nozzle array arrangement in the print head 28 of the fourth embodiment is the same as that of the first embodiment shown in FIG. That is, the number of nozzles constituting the black nozzle row is twice the number of nozzles constituting each chromatic color nozzle row.

  In the example of FIG. 12, the recording method from the first pass to the seventh pass is the same as the example of FIG. In the example of FIG. 12, when the seventh pass in the forward direction is completed, a part of the unit band to be formed in the next eighth pass in the backward direction is located in the color area. Therefore, according to the recording method in the color area, the next backward pass eighth pass is a black / chromatic color combined pass. However, in the fourth embodiment, the unit band immediately before the boundary with the color area in the monochrome area is in the same direction as the specific direction (direction of the combined black and chromatic color path) described above when forming the other color areas. If the path is formed by a path, the next path after the path for forming the immediately preceding unit band is only a chromatic color opposite to the specific direction, and the next path is black and It is supposed to be a coloring combination pass. In the example of FIG. 12, the unit band immediately before the boundary with the color area in the monochrome area is formed by the seventh path that is the same direction as the specific direction (that is, the forward direction) in the first color area. The eighth pass, which is a path of the second color, is a chromatic color path in the reverse direction (reverse direction) to the specific direction, and the subsequent ninth path is a black / chromatic color combined path in the same direction as the specific direction (forward direction). The subsequent unit band of the color area is formed by one backward chromatic color pass followed by one forward black / chromatic color combined pass.

As described above, in the inkjet printer 20 of the fourth embodiment, assuming that the number of nozzles constituting each nozzle row for chromatic color is K, the number of nozzles constituting the nozzle row for black is (n · K). (Where n = 2). In the printing process by the inkjet printer 20 of the fourth embodiment, in the color region, the forward and backward passes are alternately repeated, and the black and chromatic color combined pass in a specific direction (for example, the forward direction) is specified. A recording method in which a unit band is formed by a total of two passes (image forming operation) including only one chromatic color pass in the direction opposite to the direction (for example, the backward direction) is employed. That is, in each color region, the pass directions in which the black nozzle rows are used are all the same direction (specific direction). Therefore, in the fourth embodiment, as in the first embodiment, the occurrence of ruled line misalignment can be suppressed, and the print image quality can be improved.
In the fourth embodiment, the number of nozzles constituting the black nozzle row is set to be twice the number of nozzles constituting each chromatic color nozzle row, and the unit band is used once in the color region for the black / chromatic color combined pass. Since only one chromatic color is formed with a pass, it is possible to suppress a decrease in printing speed while suppressing occurrence of ruled line position deviation. Further, in the fourth embodiment, in the monochrome area, a recording method is adopted in which passes only in the forward and backward black are alternately repeated and a unit band is formed by only one black pass. The printing speed can be improved in a monochrome area where the ink amount per area is relatively small and the risk of occurrence of ruled line position deviation is small. From the above, the inkjet printer 20 of the fourth embodiment can improve the print image quality while suppressing an increase in the time required for the printing process as in the first embodiment.

  Also in the inkjet printer 20 of the fourth embodiment, when the unit band immediately before the boundary with the color area in the monochrome area is formed by a path in the same direction as the specific direction described above when forming the other color area. The next path after the path for forming the unit band immediately before is a path for chromatic colors opposite to the specific direction, and the next path is a black / chromatic color combined path for the specific direction. It is said. Therefore, in the fourth embodiment, the direction of the black and chromatic color combined pass is unified in the same direction in all the color regions in the printed image, the occurrence of color unevenness can be suppressed, and the print image quality can be further improved. Can do. In the fourth embodiment, since there is no empty pass that does not involve the use of either the black nozzle row or the chromatic color nozzle row, an increase in the time required for the printing process can be more effectively suppressed.

E. Variations:
The present invention is not limited to the above-described examples and embodiments, and can be implemented in various modes without departing from the gist thereof. For example, the following modifications are possible.

E1. Modification 1:
In each of the above embodiments, if the number of nozzles constituting each chromatic color nozzle row is K and the number of nozzles constituting the black nozzle row is (n · K), the value of n is 2 or 4. However, the value of n may be any value other than 2 and 4 as long as it is an integer of 2 or more. Regardless of the value of n, in the color region, the forward and backward passes are alternately repeated, and one black / chromatic color combined pass in a specific direction and (m−1) forward and backward passes. A recording method in which a unit band is formed by a total of m passes (image forming operation) with only a chromatic color pass (m is an integer of 2 or more and n or less) is adopted, and only one black pass is passed in the monochrome area. A recording method in which a unit band is formed may be adopted.

  When the value of n is an even number, the combination of the direction of a series of passes for forming each unit band can be unified in each color region. For example, when the recording method in which the value of n is 4 and a unit band is formed by a total of four passes is adopted, the combination of the direction of a series of passes for forming each unit band is, for example, , Forward direction, backward direction, forward direction, and backward direction can be unified. On the other hand, for example, when a recording method in which the value of n is 3 and a unit band is formed by a total of three passes is adopted, the combination of the direction of a series of passes for forming each unit band is For example, the combination of the direction of a series of paths is a combination of the forward direction, the backward direction, and the forward direction for a certain unit band, and the combination of the backward direction, the forward direction, and the backward direction for the next unit band. It is difficult to unify. If the combination of the directions of a series of passes for forming each unit band is not unified, the processing becomes complicated, for example, adjustment of the transport amount in the transport operation is necessary to eliminate missing of the main scanning line (raster). There is a fear. Therefore, it is preferable that the value of n is an even number from the viewpoint of speeding up by simplification of processing.

  In each of the above embodiments, a recording method is adopted in which the pass is repeated alternately only in the forward and backward black directions in the monochrome area. However, in the monochrome area, only the black in the forward and backward directions is used. A recording method in which only the pass is repeated may be employed. In this way, it is possible to effectively suppress the occurrence of misalignment of the ruled lines in the monochrome area, although there is a risk of increasing the printing time.

E2. Modification 2:
In each of the above-described embodiments, the first specific direction pass among the multiple passes performed for forming the unit band in the color region is the black / chromatic color combined pass, but it is not always necessary to do so. . For example, in the example of FIG. 8, the second specific direction path, not the first path that is the first specific direction path among the first to fourth paths performed for forming the first unit band. The third pass may be a black / chromatic color combined pass. That is, as long as the direction of the black / chromatic color combination pass is unified in a certain color area, one of the multiple passes performed for forming the unit band is used as the black / chromatic color combined pass. The remaining paths may be chromatic colors only. However, since the amount of ink in the unit band region on the print medium increases each time the passes are overlapped and the deflection of the print medium tends to increase, among the multiple passes performed for forming the unit band, It is preferable from the viewpoint of suppressing the occurrence of ruled line deviation that the path executed earlier is a black / chromatic color combined path.

E3. Modification 3:
In each of the above embodiments, when the unit band immediately before the boundary with the color area in the monochrome area is formed by the path in the same direction as the specific direction described above when forming the other color area, for example, The pass after the pass for forming the unit band is an empty pass opposite to the specific direction that does not involve the use of either the black nozzle row or the chromatic color nozzle row. In this way, the direction of the black and chromatic color combined pass is unified in the same direction for all the color areas in the printed image, and the print quality is further improved by suppressing the occurrence of color unevenness. In such a case, for example, the empty pass is not executed, and the pass next to the pass for forming the unit band immediately before may be used as the pass for forming the color region. . Even in this case, if the individual color regions in the printed image are viewed, the directions of the paths in which the black nozzle rows are used are all the same direction (specific direction), and therefore the occurrence of ruled line deviation can be suppressed. .

E4. Modification 4:
The configuration of the inkjet printer 20 in each of the above embodiments is merely an example, and the configuration of the inkjet printer 20 can be variously modified. For example, in each of the embodiments described above, the inkjet printer 20 is a printer that performs printing using a total of four inks, black ink as an achromatic color and cyan, magenta, and yellow ink as chromatic colors. The inkjet printer 20 may be a printer that performs printing using four or less colors, or six or more colors, as long as both the achromatic color ink and the chromatic color ink are included. Regardless of the number of ink colors used, the print head 28 of the inkjet printer 20 is provided with a nozzle row corresponding to each ink color.

  In each of the above embodiments, the inkjet printer 20 receives the print signal PS from the computer 88 and performs printing. However, the inkjet printer 20 does not necessarily receive the print signal PS from the computer 88 and perform printing. The inkjet printer 20 may perform printing based on data held by the inkjet printer 20 itself without the involvement of the computer 88.

  In each of the above embodiments, a part of the configuration realized by hardware may be replaced by software, and conversely, a part of the configuration realized by software may be replaced by hardware. Also good.

  In addition, when part or all of the functions of the present invention are realized by software, the software (computer program) can be provided in a form stored in a computer-readable recording medium. In the present invention, the “computer-readable recording medium” is not limited to a portable recording medium such as a flexible disk or a CD-ROM, but an internal storage device in a computer such as various RAMs and ROMs, a hard disk, etc. It also includes an external storage device fixed to the computer.

DESCRIPTION OF SYMBOLS 20 ... Inkjet printer 22 ... Paper feed motor 24 ... Carriage motor 26 ... Platen 28 ... Print head 30 ... Carriage 34 ... Sliding shaft 36 ... Drive belt 38 ... Pulley 39 ... Position detection sensor 40 ... Control circuit 41 ... CPU
42 ... ROM
43 ... ROM
44 ... RAM
52 ... head drive circuit 54 ... motor drive circuit 56 ... connector 60 ... print head unit 88 ... computer

Claims (5)

A printing device,
A chromatic color nozzle array composed of K (K is an integer of 2 or more) nozzles that discharge chromatic color inks aligned along the first direction, and an achromatic color aligned along the first direction An achromatic color nozzle array composed of (n · K) (n is an integer of 2 or more) nozzles that eject ink, and arranged along a second direction that intersects the first direction. A plurality of nozzle rows arranged in
A moving mechanism for reciprocally moving the plurality of nozzle rows relative to the print medium along the second direction;
A transport mechanism that transports the print medium relative to the plurality of nozzle rows along the first direction;
An image forming operation for causing the plurality of nozzle rows to eject ink while causing the moving mechanism to move the plurality of nozzle rows in the forward and backward directions; and a transport operation for causing the transport mechanism to transport the print medium. And a controller that forms an image on the print medium by repeating
In the color region including the chromatic color in the image, the control unit performs m times (m is an integer of 2 to n) in which the movement direction of the plurality of nozzle rows is alternately switched between the forward direction and the backward direction. In the forming operation, the moving direction of the plurality of nozzle rows is a specific direction that is one of the forward direction and the backward direction, and both the chromatic color nozzle row and the achromatic color nozzle row are used. Along the first direction of the image by m image forming operations including one image forming operation and (m-1) image forming operations in which only the chromatic color nozzle row is used. In the monochrome area that does not include a chromatic color in the image, the predetermined width area of the image is formed by one image forming operation in which only the achromatic color nozzle row is used. Together with the picture In for all of the color region such that the specific direction is the same direction, effect formation of the image, the printing apparatus. The printing apparatus according to claim 1,
The control unit performs the first image forming operation in which the moving direction of the plurality of nozzle rows is the specific direction among the m image forming operations, the chromatic color nozzle row and the achromatic color nozzle row. And a printing apparatus in which the image forming operation is performed once. The printing apparatus according to claim 1 or 2, wherein
The printing apparatus, wherein the value of n is an even number. A chromatic color nozzle array composed of K (K is an integer of 2 or more) nozzles that discharge chromatic color inks aligned along the first direction, and an achromatic color aligned along the first direction An achromatic color nozzle array composed of (n · K) (n is an integer of 2 or more) nozzles that eject ink, and arranged along a second direction that intersects the first direction. A plurality of nozzle rows arranged in the above, a moving mechanism for reciprocally moving the plurality of nozzle rows relative to the print medium along the second direction, and the print medium with respect to the plurality of nozzle rows. And a transport mechanism that transports relatively along the first direction.
An image forming operation for causing the plurality of nozzle rows to eject ink while causing the moving mechanism to move the plurality of nozzle rows in the forward and backward directions; and a transport operation for causing the transport mechanism to transport the print medium. , Including the step of forming an image on the print medium by repeating
In the step of forming the image, in the color region including the chromatic color in the image, the moving direction of the plurality of nozzle rows is alternately switched between the forward direction and the backward direction (m is an integer of 2 to n) In the image forming operation, the moving direction of the plurality of nozzle rows is a specific direction that is one of a forward direction and a backward direction, and both the chromatic color nozzle row and the achromatic color nozzle row The first image of the image is obtained by m times of the image forming operation including one image forming operation in which only the chromatic color nozzle row is used and (m−1) times of the image forming operation in which only the chromatic color nozzle row is used. In a monochrome region that does not include a chromatic color in the image and that forms a region having a predetermined width along the direction, the region of the predetermined width of the image is formed by one image forming operation in which only the achromatic color nozzle row is used. to form a , As the specific direction for all of the color area in the image are the same direction, a step for forming the image, method. A chromatic color nozzle array composed of K (K is an integer of 2 or more) nozzles that discharge chromatic color inks aligned along the first direction, and an achromatic color aligned along the first direction An achromatic color nozzle array composed of (n · K) (n is an integer of 2 or more) nozzles that eject ink, and arranged along a second direction that intersects the first direction. A plurality of nozzle rows arranged in the above, a moving mechanism for reciprocally moving the plurality of nozzle rows relative to the print medium along the second direction, and the print medium with respect to the plurality of nozzle rows. A computer program for controlling a printing apparatus comprising: a transport mechanism that transports relatively along the first direction;
An image forming operation for causing the plurality of nozzle rows to eject ink while causing the moving mechanism to move the plurality of nozzle rows in the forward and backward directions; and a transport operation for causing the transport mechanism to transport the print medium. , By causing the printing apparatus to realize a control function for forming an image on the print medium by repeating
In the color function including the chromatic color in the image, the control function is m times (m is an integer not smaller than 2 and not larger than n) in which the moving direction of the plurality of nozzle rows is alternately switched between the forward direction and the backward direction. In the forming operation, the moving direction of the plurality of nozzle rows is a specific direction that is one of the forward direction and the backward direction, and both the chromatic color nozzle row and the achromatic color nozzle row are used. Along the first direction of the image by m image forming operations including one image forming operation and (m-1) image forming operations in which only the chromatic color nozzle row is used. In the monochrome area that does not include a chromatic color in the image, the predetermined width area of the image is formed by one image forming operation in which only the achromatic color nozzle row is used. Together with the above As the specific direction for all of the color area in the image are the same direction, a function for forming the image, the computer program.

Images