JP2014162184A - Printing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce image quality deterioration of a gray image printed with inks having a complementary color relation.SOLUTION: A printing apparatus includes: a first nozzle array group having multiple first nozzle arrays in which multiple nozzles ejecting an ink are arranged in a predetermined direction and positions in a predetermined direction are mutually the same; a second nozzle array group having multiple second nozzle arrays in which multiple nozzles are arranged in a predetermined direction and positions in a predetermined direction that is different from the predetermined direction in the first nozzle arrays are mutually the same; and a control part repeats an operation of ejecting inks from nozzles and another operation of relatively moving the nozzle array groups and a medium in a predetermined direction while relatively moving the nozzle array groups and the medium in a direction crossing the predetermined direction. Inks having a complementary color relation are ejected respectively from a nozzle array belonging to the same nozzle array group in the first nozzle array group and the second nozzle array group.

Description

  The present invention relates to a printing apparatus.

  As an example of a printing apparatus, an ejection operation for ejecting ink from nozzles while moving a head including a nozzle row in which a plurality of nozzles are arranged in a predetermined direction in a moving direction intersecting the predetermined direction, and a movement for moving the head in a predetermined direction Ink jet printers that repeat operation are known.

  In order to perform high-density printing, there has been proposed a printing apparatus in which inks of the same color are assigned to a plurality of nozzle rows whose nozzle positions are shifted in the nozzle row direction (see Patent Document 1).

JP 2010-208164 A

  By mixing inks having complementary colors (for example, magenta ink and green ink), a gray image that is a halftone between black and white can be printed. However, when the inks having the complementary color relationship are respectively assigned to the nozzle rows whose nozzle positions are shifted in the nozzle row direction, the gray images are printed by overlapping the inks ejected by different ejection operations. For this reason, for example, when medium expansion / contraction or head movement error occurs between ejection operations, the dot rows of inks having complementary colors cannot be appropriately overlapped, and the image quality of the gray image is deteriorated.

  Therefore, an object of the present invention is to reduce image quality deterioration of a gray image printed with ink having a complementary color relationship.

  A main invention for solving the above problems is a plurality of first nozzle rows in which a plurality of nozzles for ejecting ink are arranged in a predetermined direction, and the positions of the nozzles in the predetermined direction are the same. A first nozzle row group including one nozzle row and a plurality of second nozzle rows in which a plurality of nozzles for ejecting ink are arranged in the predetermined direction, and the positions of the nozzles in the predetermined direction are the same; The second nozzle row group including a plurality of second nozzle rows different from the positions of the nozzles in the predetermined direction of the first nozzle row, the first nozzle row group, the second nozzle row group, and the medium. An operation of ejecting ink from the nozzles while relatively moving in a direction crossing a predetermined direction, and an operation of relatively moving the first nozzle row group, the second nozzle row group, and the medium in the predetermined direction. repeat And a control unit that discharges ink having a complementary color relationship from nozzle rows belonging to the same nozzle row group of the first nozzle row group and the second nozzle row group. It is a printing device.

  Other features of the present invention will become apparent from the description of this specification and the accompanying drawings.

1 is a block diagram illustrating an overall configuration of a printing system. 2A is a schematic sectional view of the printer, and FIG. 2B is a schematic top view of the printer. It is a figure which shows the arrangement | sequence of the nozzle provided in the head. 4A is a diagram showing a nozzle arrangement of a comparative example, FIG. 4B is an explanatory diagram of a gray image printing method, and FIG. 4C is an explanatory diagram of an image printed on paper. It is explanatory drawing of the image printed when the movement error of a head generate | occur | produces. 6A is a diagram illustrating the nozzle arrangement of the first embodiment, FIG. 6B is an explanatory diagram of a gray image printing method, and FIG. 6C is an explanatory diagram of an image printed on paper. It is explanatory drawing of the image printed when the movement error of a head generate | occur | produces. FIG. 6 is a diagram for explaining a nozzle arrangement of Example 2.

=== Summary of disclosure ===
At least the following will become apparent from the description of the present specification and the accompanying drawings.

That is, a first nozzle row comprising a plurality of first nozzle rows in which a plurality of nozzles that eject ink are arranged in a predetermined direction, and the positions of the nozzles in the predetermined direction are the same. A plurality of second nozzle rows in which a group and a plurality of nozzles that eject ink are arranged in the predetermined direction, and the positions of the nozzles in the predetermined direction are the same and the nozzles of the first nozzle row A second nozzle row group having a plurality of second nozzle rows different from the position in the predetermined direction, and the relative movement of the first nozzle row group, the second nozzle row group, and the medium in a direction intersecting the predetermined direction And a controller that repeats an operation of ejecting ink from the nozzles and an operation of relatively moving the first nozzle row group, the second nozzle row group, and the medium in the predetermined direction. The first From the nozzle row belonging to the same nozzle row group of the nozzle row group and the second nozzle row group, the ink having a complementary relationship is discharged respectively, a printing apparatus according to claim.
According to such a printing apparatus, each operation (pass) for ejecting ink from the nozzle can form dots of ink having a complementary color relationship at the same position in a predetermined direction (nozzle row direction). Pass) can complete a gray dot row. Therefore, even if a relative movement error between the nozzle array group and the medium occurs or the medium expands and contracts, it is possible to suppress the occurrence of complementary ink-related ink streaks on the gray image, and the gray image quality deteriorates. Can be reduced.

This printing apparatus has a heating support section that heats while supporting the medium.
According to such a printing apparatus, it is possible to promote drying of the ink that has landed on the medium. Further, even when the medium expands and contracts due to the heat of the heating support portion, it is possible to reduce the deterioration of the gray image quality.

In such a printing apparatus, the complementary inks are a magenta ink and a green ink.
According to such a printing apparatus, it is possible to reduce deterioration in image quality of a gray image printed with magenta ink and green ink.

In such a printing apparatus, the complementary inks are a cyan ink and an orange ink.
According to such a printing apparatus, it is possible to reduce image quality deterioration of a gray image printed with cyan ink and orange ink.

This printing apparatus is characterized in that yellow ink and clear ink are respectively ejected from nozzle rows belonging to different nozzle row groups among the first nozzle row group and the second nozzle row group. It is.
According to such a printing apparatus, not only the ink ejected from the nozzle array belonging to the same nozzle array group as the clear ink but also the image (medium) by the ink ejected from the nozzle array belonging to the nozzle array group different from the clear ink. The filling of can also be improved.

=== Printing system ===
Hereinafter, an embodiment will be described by taking a printing system in which an inkjet printer (printing apparatus) and a computer are connected as an example.
FIG. 1 is a block diagram showing the overall configuration of the printing system. 2A is a schematic cross-sectional view of the inkjet printer 1 (hereinafter, printer 1), and FIG. 2B is a schematic top view of the printer 1. FIG. FIG. 3 is a diagram illustrating an arrangement of nozzles (openings) provided in the head 41. The printer 1 includes a controller 10, a transport unit 20, a drive unit 30, a head unit 40, and a detector group 50. The printer 1 is communicably connected to the computer 60, and a printer driver installed in the computer 60 creates print data for causing the printer 1 to print an image and outputs the print data to the printer 1.

  A controller 10 in the printer 1 is for performing overall control in the printer 1. The interface unit 11 transmits and receives data to and from the computer 60 that is an external device. The CPU 12 is an arithmetic processing device for performing overall control of the printer 1, and controls each unit via the unit control circuit 14. The memory 13 is for securing an area for storing a program of the CPU 12, a work area, and the like. The situation in the printer 1 is monitored by the detector group 50, and the controller 10 performs control based on the detection result from the detector group 50.

  The transport unit 20 transports the continuous paper S (corresponding to a medium) in a transport direction that is a direction in which the continuous paper S continues, and includes a transport roller 21. Specifically, the transport roller 21 feeds the continuous paper S wound up in a roll shape and supplies it to the printing area, and discharges the printed continuous paper S from the printing area and winds it up in a roll shape. Note that the medium on which the printer 1 prints an image is not limited to paper, and may be, for example, cloth or film. Further, not only the continuous paper S but cut paper may be used.

  The drive unit 30 moves the head 41 for ejecting ink in the main scanning direction (conveying direction of the continuous paper S) with respect to the continuous paper S positioned in the printing area, and moves the head 41 in the sub-scanning direction. And a Y-axis stage 32 that moves in a direction that intersects the transport direction.

  The head unit 40 has a platen 42 that supports the continuous paper S positioned in the printing area from a surface opposite to the printing surface, and a head 41 that ejects ink onto the continuous paper S supported by the platen 42 to print an image. Have one or more. As shown in FIG. 3, a plurality of nozzles Nz (openings) for ejecting ink are predetermined in the sub-scanning direction (corresponding to a predetermined direction) on the surface of the head 41 facing the paper S (the lower surface in this embodiment). Eight nozzle rows arranged at every interval D are formed. In FIG. 3, it is assumed that one nozzle row has 360 nozzles Nz, and numbers are sequentially assigned starting from the nozzles Nz located on one side in the sub-scanning direction (# 1, # 2,... # 360). . The ink ejection method from the nozzle Nz may be a piezo method in which ink is ejected from the nozzle Nz by applying a voltage to the drive element (piezo element) to expand and contract the ink chamber, or a nozzle using a heating element. A thermal method in which bubbles are generated in Nz and ink is ejected from the nozzles Nz by the bubbles may be used.

  The eight nozzle rows provided in the head 41 are divided into an A row group and a B row group. The positions of the nozzles Nz included in the four nozzle rows A1 to A4 (corresponding to the first nozzle row) belonging to the A row group (corresponding to the first nozzle row group) are the same as each other. Further, the positions of the nozzles Nz of the four nozzle rows B1 to B4 (second nozzle row) belonging to the B row group (corresponding to the second nozzle row group) are the same as each other in the A row group. It is different from the position in the sub-scanning direction of the nozzles Nz included in the nozzle rows A1 to A4 to which the nozzle arrays A1 to A4 belong. Specifically, with respect to the nozzles Nz included in the nozzle rows A1 to A4 belonging to the A row group, the nozzles Nz included in the nozzle rows B1 to B4 belonging to the B row group are only half the nozzle interval D of each nozzle row. It is shifted to the other side in the sub-scanning direction. Therefore, for example, nozzle # 1 of nozzle row B1 is located between nozzle # 1 and nozzle # 2 of nozzle row A1. In FIG. 3, the number of nozzle rows belonging to the A row group is the same as the number of nozzle rows belonging to the B row group, but this is not limiting, and the number of nozzle rows is different between the A row group and the B row group. Also good.

  In addition, a plurality of heaters 43 (for example, nichrome wires) are disposed inside the platen 42, and the temperature of the platen 42 rises due to the heat generated by the heater 43, and the continuous paper S on the platen 42 is heated. As a result, it is possible to promote drying of the ink that has landed on the continuous paper S on the platen 42, and it is possible to suppress bleeding of the ink in the printed image. That is, the platen 42 corresponds to a heating support unit that heats the continuous paper S while supporting it. Not only the heater 43 is provided inside the platen 42, but also a drying furnace (corresponding to a heating support portion, not shown) for heating while supporting the continuous paper S is provided downstream of the platen 42 in the transport direction. Also good. The drying of the image printed on the continuous paper S can be promoted by the drying furnace.

  In the printer 1 having the above-described configuration, the controller 10 (corresponding to the control unit) moves the head 41 (the A-row group and the B-row group) in the main scanning direction by the X-axis stage 31 with respect to the continuous paper S positioned in the printing area. An image forming operation for alternately repeating an ejection operation (pass) for ejecting ink from the nozzle Nz while moving and a moving operation for moving the head 41 to the other side in the sub-scanning direction by the Y-axis stage 32 is executed. As a result, a two-dimensional image is printed on the continuous paper S located in the printing area. Thereafter, the controller 10 causes the transport unit 20 to discharge the portion of the continuous paper S on which the image has been printed from the print area, and to perform a transport operation for supplying the portion of the continuous paper S that has not yet been printed to the print area. . By repeating the image forming operation and the conveying operation in this manner, an image is printed along the continuous direction of the continuous paper S.

=== Ink ===
The printer 1 of the present embodiment has eight types of ink, that is, black ink (K), cyan ink (C) as primary colors, magenta ink (M), yellow ink (Y), and secondary colors. Green ink (Gr), orange ink (Or), white ink (W), and clear ink (Cl) can be ejected. Therefore, eight types of ink are allocated to the eight nozzle rows provided in the head 41, respectively. The clear ink (Cl) is a colorless and transparent ink that contains, for example, polymer fine particles, does not contain a colorant, and does not react with other colored inks. However, clear ink also includes ink that exhibits a slight tint due to components other than the colorant, such as polymer fine particles and organic solvents in the clear ink.

  In the printer 1 of the present embodiment, clear ink is used when it is desired to ensure the abrasion resistance of the image with colored ink and when it is desired to improve the filling of the image with colored ink (filling of the paper S). When it is desired to ensure the abrasion resistance of the image, the printer 1 ejects clear ink onto the colored image after printing the image with the colored ink on the paper S. By doing so, the colored image is covered with a layer of clear ink, and the abrasion resistance can be ensured. In this case, since the unevenness on the surface is reduced, the gloss is also improved. On the other hand, when it is desired to improve the filling of the image with the colored ink, the printer 1 ejects the ink so that the colored ink and the clear ink overlap on the paper S. That is, colored ink and clear ink are ejected toward the same position on the paper S in the same pass. By doing so, the colored ink wets and spreads by the clear ink, and the dot diameter of the colored ink can be made larger than when the colored ink is landed on the paper S alone. Therefore, the filling of the image with colored ink can be improved.

  The inks that are complementary to each other that can be ejected by the printer 1 of the present embodiment are “magenta ink (M) and green ink (Gr)”, and “cyan ink (C) and orange ink”. (Or) ". The ink having a complementary color relationship is an ink that becomes gray (achromatic color) when mixed at an appropriate ratio, and is an ink of a color that is on a diagonal line in the hue circle. However, it is not limited to a complementary color relationship in a strict sense, but also includes an ink of a certain color and a color located on the complementary color side of the color, such as the above-described cyan ink and orange ink. That is, ink that can print a gray image (a halftone image of black and white) by mixing colors is an ink having a complementary color relationship.

=== Nozzle arrangement ===
<<< comparative example >>>
4A is a diagram showing a nozzle arrangement of a comparative example, FIG. 4B is an explanatory diagram of a gray image printing method, and FIG. 4C is an explanatory diagram of an image printed on the paper S by the printing method of FIG. 4B. It is. FIG. 5 is an explanatory diagram of an image printed when a movement error of the head 41 occurs. In the following drawings, the number of nozzles belonging to the nozzle row is reduced for the sake of simplicity. FIG. 4B is a diagram showing the positional relationship of the nozzles between passes.

  In the comparative example, yellow ink Y is ejected from the nozzle row A1 of the A row group, cyan ink C is ejected from the nozzle row A2 of the A row group, clear ink Cl is ejected from the nozzle row A3 of the A row group, and A The green ink Gr is ejected from the nozzle row A4 of the row group, the magenta ink M is ejected from the nozzle row B1 of the B row group, the black ink K is ejected from the nozzle row B2 of the B row group, and the nozzle rows of the B row group The nozzle arrangement is such that orange ink Or is ejected from B3 and white ink W is ejected from nozzle row B4 of the B row group. That is, in the comparative example, the green ink Gr and the magenta ink M, which are inks having complementary colors, are respectively ejected from nozzle rows belonging to different nozzle row groups, and the cyan ink C and the orange ink Or, which are also complementary colors, are obtained. Discharge is performed from nozzle rows belonging to different nozzle row groups.

  Here, a case where a gray image is printed by mixing green ink Gr and magenta ink M, which are complementary colors, will be described. In this case, as shown in FIG. 4B, an ejection operation (pass) in which the green ink Gr and the magenta ink M are ejected from the head 41 while moving the head 41 in the moving direction (main scanning direction), and the head 41 is moved in the sub-scanning direction. The moving operation of moving to the other side is alternately repeated. Note that the amount of movement of the head 41 in one movement operation is set to ¼ of the nozzle interval D in the nozzle row.

  As a result, as shown in FIG. 4C, in pass 1, magenta dot rows (M) and green dot rows (Gr) extending in the moving direction (main scanning direction) of the head 41 are alternately arranged in the sub-scanning direction. Printed. Thereafter, in pass 2, magenta dot rows (M) and green dot rows (Gr) are alternately printed between the dot rows printed in pass 1. Then, in pass 3, a green dot row (Gr) is printed on the magenta dot row (M) printed in pass 1 to form a gray dot row (M + Gr). The magenta dot row (M) is overlaid on the green dot row (Gr) thus printed to form a gray dot row (Gr + M). Thereafter, in pass 4, the green dot row (Gr) or the magenta dot row (M) is printed on the magenta dot row (M) or green dot row (Gr) printed in pass 2, respectively. A gray dot row is formed. Thus, a gray image in which gray dot rows are arranged in the sub-scanning direction is printed.

  As described above, in the comparative example, the green ink Gr and the magenta ink M, which are inks having complementary colors, are assigned to different nozzle row groups. Therefore, the green dot row and the magenta dot row formed in different passes are used. A gray image is printed by overlapping. Therefore, in the comparative example, an error occurs in the amount of movement of the head 41 in the sub-scanning direction, the sheet S on the platen 42 contracts due to the heat of the heater 43 provided in the platen 42, or a drying furnace (not shown). If the sheet S on the platen 42 is pulled due to the contraction of the sheet S in (), the magenta dot row (M) and the green dot row (Gr) cannot be properly overlapped.

  FIG. 5 shows a case where a movement error occurs in the movement operation of the head 41. Specifically, this is the case where the amount of movement of the head 41 is small and a dot row is formed by shifting to one side in the sub-scanning direction. Originally, as shown in FIG. 4C, a dot row of pass 2 is formed between the dot rows printed in pass 1, but in the case of FIG. 5, a part of the dot row printed in pass 1 is passed. 2 dot rows are formed in an overlapping manner. As a result, the magenta dot row (M) and the green dot row (Gr) do not overlap properly in pass 3 and pass 4, and magenta stripes and green stripes appear on the gray image. It will deteriorate. In particular, since magenta and green streaks that are complementary to each other appear alternately, image quality deterioration is easily visible. In addition, even if the magenta dot row and the green dot row overlap, the region where the magenta dot row overlaps (M + M + Gr) becomes gray with a strong magenta color, and the green dot row overlaps. In the region (Gr + Gr + M), the gray color is strong with a green color, and the image quality of the gray image is degraded.

  Further, as described above, the printer 1 of the present embodiment ejects ink so that the colored ink and the clear ink overlap on the paper S when it is desired to improve the filling of the image with the colored ink. Therefore, as in the comparative example, if the inks (Gr, M) having a complementary color relationship are assigned to different nozzle row groups, the green ink Gr and the clear ink Cl are ejected at the same position on the paper S in each pass. However, the magenta ink M and the clear ink Cl are ejected to different positions on the paper S in each pass. Therefore, compared with the magenta ink M, the green ink Gr is more influenced by the clear ink Cl, the dot diameter becomes larger, and a gray image with a strong green tint is printed. That is, if the complementary color relationship ink is assigned to different nozzle row groups, a gray image with a strong tint of ink assigned to the same nozzle row group as the clear ink among the complementary color relationship inks is printed. The image quality of the gray image is deteriorated.

  Therefore, an object of the present embodiment is to reduce image quality deterioration of a gray image printed by mixing inks having complementary colors. The case where the gray image is printed with the green ink Gr and the magenta ink M has been described as an example, but the same problem occurs when the gray image is printed with the cyan ink C and the orange ink Or.

<<< Example 1 >>>
6A is a diagram illustrating the nozzle arrangement of the first embodiment, FIG. 6B is an explanatory diagram of a gray image printing method, and FIG. 6C is an explanation of an image printed on the paper S by the printing method of FIG. 6B. FIG. FIG. 7 is an explanatory diagram of an image that is printed when a movement error of the head 41 occurs. In Example 1, yellow ink Y is ejected from nozzle row A1 of the A row group, white ink W is ejected from nozzle row A2 of the A row group, clear ink Cl is ejected from nozzle row A3 of the A row group, Black ink K is ejected from nozzle row A4 of the A row group, green ink Gr is ejected from nozzle row B1 of the B row group, cyan ink C is ejected from nozzle row B2 of the B row group, and nozzles of the B row group It is assumed that the orange ink Or is ejected from the row B3 and the magenta ink M is ejected from the nozzle row B4 of the B row group.

  In other words, in the first embodiment, the green ink Gr and the magenta ink M, which are inks having complementary colors, are ejected from the nozzle rows belonging to the same nozzle row group (here, the B row group), and are also complementary colors. Cyan ink C and orange ink Or are ejected from nozzle rows belonging to the same nozzle row group (here, B row group).

  Here, a case where a gray image is printed by mixing green ink Gr and magenta ink M having a complementary color relationship will be described. In this case, as shown in FIG. 6B, an ejection operation (pass) in which the green ink Gr and the magenta ink M are ejected from the head 41 while moving the head 41 in the moving direction (main scanning direction), and the head 41 is moved in the sub-scanning direction. The moving operation of moving the length of 1/4 of the nozzle interval D to the other side of the nozzle is alternately repeated. As a result, as shown in FIG. 6C, in each pass, the green dot row (Gr) and the magenta dot row (M) are printed in the same position in the sub-scanning direction, and a gray dot row is completed for each pass. To do. Then, a gray dot row (Gr + M) is formed in each pass of pass 2 to pass 4 between the gray dot rows (Gr + M) formed in pass 1, and the gray dot rows are arranged in the sub-scanning direction. The image is printed.

  In this way, by ejecting ink having a complementary color relationship from each of the nozzle rows belonging to the same nozzle row group of the A row group and the B row group, the dots of the ink having the complementary color relationship are discharged in the sub-scanning direction ( Nozzle row direction) can be formed at the same position, and a gray dot row can be completed in each pass. Therefore, even if an error occurs in the amount of movement of the head 41 in the sub-scanning direction or the sheet S expands or contracts due to the heat of the heater 43 in the platen 42 or the like, as in the comparative example (FIG. 5), Thus, magenta streaks and green streaks can be prevented from appearing, and image quality deterioration of a gray image printed with ink having a complementary color relationship can be reduced.

  For example, a case where the moving amount of the head 41 is small and the dot row is formed by shifting to one side in the sub-scanning direction will be described as an example. In this case, in Example 1 (FIG. 7), a part (gr + gr) that is printed with the gray dot line of pass 2 overlapped with a part of the gray dot line printed in pass 1 and is visually recognized as a slightly dark gray is obtained. Although it occurs, no magenta or green streak occurs as in the comparative example (FIG. 5). The dark gray streaks on the gray image are less visible than the magenta or green streaks, and it can be said that the image quality deterioration of the gray image can be reduced in the first embodiment compared to the comparative example. Further, in the first embodiment, the dot row of one of the complementary colors does not overlap as in the comparative example (for example, the M + M + Gr dot row or the Gr + Gr + M dot row in the comparative example (FIG. 5)). In other words, there is no gray portion where the color of one of the complementary colors is strong. Also from this point, it can be said that Example 1 can reduce the deterioration of the image quality of the gray image as compared with the comparative example.

  However, when the movement amount of the head 41 is small as shown in FIG. 7 and a dot row is formed by shifting to one side in the sub-scanning direction, the gray color formed in pass 1 and pass 4 is used in the first embodiment. White stripes are generated between the dot rows (gr). Therefore, a gray image may be printed using not only the green ink Gr and the magenta ink M ejected from the nozzle row of the B row group but also the black ink K ejected from the nozzle row of the A row group (not shown). . By doing so, the gray dots formed by the nozzle row (K) of the A row group between the gray dot rows formed by the nozzle row (Gr, M) of the B row group in pass 1 and pass 4. It can be filled with columns, and white streaks can be prevented from occurring in the gray image. If another set of complementary inks (cyan ink C and orange ink Or) is arranged in the A column group, cyan ink C and orange ink Or may be used instead of black ink K. Good. That is, it is preferable to distribute ink groups (a group of green ink Gr and magenta ink M, a group of cyan ink C and orange ink Or, and a group of black ink K) that can print a gray image to both nozzle row groups. By doing so, it is possible to further reduce the image quality deterioration of the gray image.

  Also, suppose that a gray image is printed using the black ink K in addition to the green ink Gr and the magenta ink M also in the nozzle arrangement of the comparative example (FIG. 4A). Even in such a case, the green streaks and the black inks overlap, and the magenta streaks and the black inks overlap, so that a gray portion having a strong tint of one of the complementary colors is generated. Therefore, the image quality deterioration of the gray image cannot be reduced in the comparative example as in the first embodiment.

  In the nozzle arrangement of the first embodiment, either the complementary color ink is assigned to the same nozzle row group as the clear ink, or is assigned to a different nozzle row group. Therefore, even when the filling of the image with the colored ink is improved by the clear ink, the ink having the complementary color relationship is ejected toward the same position on the paper S as the clear ink in each pass, or the clear ink is cleared. The ink is ejected toward a position on the paper S different from the ink. For this reason, it is possible to prevent one of the inks having a complementary color relationship from being strongly influenced by the clear ink as compared with the other ink, and to make the influence of the clear ink received by the ink having a complementary color relationship equal. be able to. Therefore, it is possible to equalize the extent of the dot diameter of the ink having a complementary color relationship, and to reduce the image quality deterioration of the gray image.

<<< Example 2 >>>
FIG. 8 is a diagram illustrating the nozzle arrangement of the second embodiment. In Example 2, yellow ink Y is ejected from the nozzle row A1 of the A row group, cyan ink C is ejected from the nozzle row A2 of the A row group, and orange ink Or is ejected from the nozzle row A3 of the A row group. Black ink K is ejected from nozzle row A4 in the A row group, green ink Gr is ejected from nozzle row B1 in the B row group, white ink W is ejected from nozzle row B2 in the B row group, and nozzles in the B row group It is assumed that the clear ink Cl is ejected from the row B3 and the magenta ink M is ejected from the nozzle row B4 of the B row group.

  As described above, by discharging the ink so that the colored ink and the clear ink overlap on the paper S, the colored ink wets and spreads, and the filling of the image with the colored ink can be improved. This is because when the colored ink and the clear ink are overlapped on the paper S, the apparent amount of the colored ink having a low density increases. Therefore, even when the yellow ink, which is a light color ink, of the inks that can be ejected by the printer 1 and other colored inks overlap on the paper S, the same effect can be obtained and the filling of the image can be improved.

  Therefore, in the second embodiment, yellow ink and clear ink are respectively ejected from nozzle rows belonging to different nozzle row groups among the A row group and the B row group. By doing so, the ink assigned to the same nozzle array group as the clear ink is ejected to the same position on the paper S as the clear ink in each pass, so that the dot diameter is increased and the filling is improved. On the other hand, since the ink allocated to the nozzle row group different from the clear ink is ejected to the same position on the paper S as the yellow ink in each pass, the dot diameter is increased and the filling is improved. That is, not only the ink assigned to the same nozzle row group as the clear ink but also the filling of the ink assigned to the nozzle row group different from the clear ink can be improved, and the image quality deterioration of the printed image can be reduced. . In other words, since it is not necessary to arrange the nozzle rows for discharging the clear ink in both nozzle row groups, the image quality of the printed image can be improved without increasing the number of nozzle rows.

=== Other Embodiments ===
The above-described embodiments are for facilitating the understanding of the present invention, and are not intended to limit the present invention. The present invention can be changed and improved without departing from the gist thereof, and it is needless to say that the present invention includes equivalents thereof.

  The type of ink ejected by the printer 1 of the above embodiment is an example. Therefore, inks having a complementary color relationship are not limited to magenta ink and green ink, and are not limited to cyan ink and orange ink. Of the inks that can be ejected by each printing apparatus, the complementary color ink may be ejected from the nozzle rows belonging to the same nozzle row group.

  In the above embodiment, two sets of inks having complementary colors are assigned to the nozzle rows belonging to the same nozzle row group, but the present invention is not limited to this. For example, yellow ink Y, cyan ink C, black ink K, and clear ink Cl may be assigned to the A row group, and green ink Gr, white ink W, orange ink Or, and magenta ink M may be assigned to the B row group. That is, one set of complementary colors (Gr and M) may be assigned to the same nozzle row group, and the other set of complementary colors (C and Or) may be assigned to different nozzle row groups.

  In the above-described embodiment, the head 41 moves in the X direction and the Y direction with respect to the continuous paper S positioned in the print area, and an operation of printing a two-dimensional image, and a new continuous paper S part is in the print area. Although the printer 1 that repeats the supplied operation is taken as an example, the present invention is not limited to this. For example, the operation of ejecting ink while the head moves in the direction intersecting the nozzle row direction (main scanning direction), and the paper in the nozzle row direction (sub-scanning direction, or in the case of continuous paper in the case of continuous paper) The printer may be a printer that repeats the transport operation for transporting the printer. Further, for example, a printer in which the operation of ejecting ink toward the paper moving in the X direction with respect to the head and the operation of moving the paper in the Y direction with respect to the head may be repeated.

1 Printer, 10 Controller, 11 Interface section,
12 CPU, 13 memory, 14 unit control circuit,
20 transport units, 21 transport rollers,
30 drive unit, 31 X-axis stage, 32 Y-axis stage,
40 head units, 41 heads, 42 platens, 43 heaters,
50 detector groups, 60 computers

Claims (5)

A first nozzle row group comprising a plurality of first nozzle rows in which a plurality of nozzles for ejecting ink are arranged in a predetermined direction, wherein the nozzles have the same position in the predetermined direction; ,
The plurality of nozzles that eject ink are a plurality of second nozzle rows arranged in the predetermined direction, and the positions of the nozzles in the predetermined direction are the same and the predetermined directions of the nozzles of the first nozzle row A second nozzle row group comprising a plurality of second nozzle rows different from the position of
An operation of ejecting ink from the nozzles while relatively moving the first nozzle row group, the second nozzle row group, and the medium in a direction crossing the predetermined direction; and the first nozzle row group and the second nozzle A controller that repeats the relative movement of the row group and the medium in the predetermined direction;
Have
Each of the first nozzle row group and the second nozzle row group is ejected with ink having a complementary color relationship from a nozzle row belonging to the same nozzle row group;
A printing apparatus characterized by the above. The printing apparatus according to claim 1,
Having a heating support section for heating while supporting the medium;
A printing apparatus characterized by the above. The printing apparatus according to claim 1 or 2, wherein
Complementary color inks are magenta ink and green ink,
A printing apparatus characterized by the above. The printing apparatus according to any one of claims 1 to 3, wherein
Complementary color inks are cyan ink and orange ink.
A printing apparatus characterized by the above. The printing apparatus according to any one of claims 1 to 4, wherein:
Yellow ink and clear ink are respectively ejected from nozzle rows belonging to different nozzle row groups among the first nozzle row group and the second nozzle row group;
A printing apparatus characterized by the above.