JP4412305B2 - Printing method, printing apparatus, and computer-readable recording medium - Google Patents

Description

  The present invention relates to a printing apparatus, and more particularly to a technique for performing printing by forming dots on a printing medium by performing main scanning and sub-scanning.

  In recent years, printing apparatuses that print images by ejecting ink droplets from nozzles while performing main scanning to form dots on a printing medium have become widespread as output devices for computers. Such a printing apparatus has a print head having the same nozzle pitch and main scan line pitch. After printing dots on a bundle of continuous main scan lines in the main scan, the print head is moved to the recorded main head. There is a technique that performs “band printing” by moving the scanning line and recording all the bundles of the next main scanning line and repeating this.

  In addition, the print head having a nozzle pitch that is an integer multiple of the main scan line pitch has a print head, and in the main scan, a dot is recorded on the main scan line in the gap between the previously recorded main scan lines, and a newly recorded area With regard to the above, there is a method of performing “interlace printing” in which dots are newly recorded on every one or several main scanning lines.

Japanese Unexamined Patent Publication No. 07-047677

  However, in band printing, since printing is performed in units of bundles of main scanning lines, lines may be seen at the boundaries between the bundles. As a result, the quality of the printed result may be lowered.

  On the other hand, in interlaced printing, the main scanning lines recorded by different main scanning are alternately positioned in the sub-scanning direction on the printing paper, so that the recording boundary is not seen. However, since each part on the printing paper cannot be recorded by one main scan, an image cannot be recorded at a position facing the print head at the start of printing and at the end of printing. That is, the printable range on the printing paper becomes narrower than the range of the relative position where the print head is sent to the printing paper in the sub-scan during printing.

  The present invention has been made in order to solve the above-described problems in the prior art, and on the printing paper with respect to the relative movement range of the printing head with respect to the printing paper while improving the quality of the printing result. The purpose is to widen the printable range.

  In order to solve at least a part of the above-described problems, in the present invention, a predetermined process is performed in a printing apparatus that performs printing by ejecting ink droplets from nozzles and landing them on a printing medium to form dots. The printing apparatus includes a print head having a plurality of nozzles arranged at a nozzle pitch k × D that is k times the main scanning line pitch D (k is an integer of 2 or more), and at least one of the print head and the print medium. A main scanning driving unit that performs main scanning, a sub scanning driving unit that performs sub scanning that moves at least one of the print head and the print medium in a direction crossing the main scanning direction, and a control unit that controls each unit. It is equipped with.

  In such a printing apparatus, k times of main scanning and (k−1) times of sub-scanning with a predetermined first feed amount (m × D) (m is an integer that is greater than or equal to 2 and k) A unit scan operation including is performed. Then, sub-scanning with a predetermined second feed amount different from the first feed amount is performed between unit scan operations. If it is such an aspect, the quality of a printing result can be made high. In addition, the printable range on the print paper can be widened with respect to the relative movement range of the print head with respect to the print paper.

  When the unit scan operation is executed using N nozzles, the second feed amount is preferably {N × k−m × (k−1)} × D. With such an aspect, it is possible to efficiently record dots on each adjacent main scanning line.

  Further, m is preferably the smallest number or the second smallest number among two or more integers that are prime with k. With such an aspect, the printable range on the printing paper can be made wider than the relative movement range of the printing head with respect to the printing paper. For example, when k is 2 or 4, or an integer of 6 or more, m is preferably 3 or 5.

  On the other hand, when printing print data including a monochrome area recorded using only achromatic ink and a color area recorded using chromatic ink, predetermined processing is performed in the following printing apparatus. Is preferred. This printing apparatus has a plurality of single-color inks each having an equal number of nozzles arranged at a nozzle pitch k1 × D which is k1 times the main scanning line pitch D (k1 is an integer of 2 or more). One chromatic nozzle group, and an achromatic nozzle group that has a larger number of nozzles than the single chromatic nozzle group arranged at a nozzle pitch k2 × D (k2 is an integer of 2 or more) and ejects achromatic ink. And a sub-scan that moves at least one of the print head and the print medium in a direction crossing the main scan direction. A sub-scanning drive unit for performing the above and a control unit for controlling each unit.

  In such a printing apparatus, in the main scan, all the nozzles of the achromatic nozzle group are used without using the nozzles of the single chromatic nozzle group, and dots are formed on the main scan line of the monochrome area. A monochrome mode unit scan operation consisting of k2 main scans and (k2-1) subscans with a predetermined first feed amount, and monochrome mode subscans with a predetermined second feed amount. Repetitive monochrome mode printing is performed while performing between unit scan operations for each monochrome mode.

  Further, in the main scanning, at least color using a specific achromatic nozzle group that is a part of the achromatic nozzle group and includes the same number of nozzles as the single chromatic nozzle group and a plurality of single chromatic nozzle groups. A dot is formed on the main scanning line of the area, and the unit scan operation for color mode, which is composed of k1 main scanning and (k1-1) sub-scanning with a predetermined third feed amount, Color mode printing is performed, in which color mode sub-scanning with a fourth feed amount that is smaller than the feed amount is repeated while being performed between each color mode unit scan operation.

  In monochrome mode printing, when predetermined conditions are satisfied, the color mode printing is started. With such an aspect, high quality printing can be performed in each of the monochrome area and the color area. Then, it is possible to efficiently shift from monochrome mode printing to color mode printing.

  A plurality of single chromatic color nozzle groups are nozzle rows each including N (N is an integer of 2 or more) nozzles arranged at a nozzle pitch k1 × D in the sub-scanning direction. When the nozzle row is composed of N × p nozzles (p is an integer of 2 or more) arranged at a nozzle pitch k2 × D in the sub-scanning direction, it is preferable to perform the following sub-scanning. That is, the first feed amount is m1 × D (m1 is 1 or more and a prime integer of k2). The second feed amount is {N * p * k2-m1 * (k2-1)} * D. The third feed amount is m2 × D (m2 is 1 or more and a prime integer of k1). The fourth feed amount is {N × k1-m2 × (k1-1)} × D. In this mode, dots can be efficiently recorded on each adjacent main scanning line in each mode.

  Both the nozzle pitch of the single chromatic nozzle group and the nozzle pitch of the achromatic nozzle group are preferably k × D (k is an integer of 2 or more), and the first feed amount and the third feed amount. Are preferably equal. With such an embodiment, the monochrome mode unit scan operation and the color mode unit scan operation can be made the same operation.

  In monochrome mode printing, when it is assumed that monochrome mode sub-scanning is to be performed next, a main scanning line on which the achromatic nozzle group can record without gaps in the sub-scanning direction in a single monochrome mode unit scan operation. It is assumed that the main scanning line at the lower end of the achromatic unit band, which is a bundle of color images, is located in the color area, and the color mode sub-scan is performed next instead of the monochrome mode sub-scan. When the main scanning line at the lower end of the achromatic unit band is located in the monochrome area, the main scanning line at the lower end of the achromatic unit band when assuming that the unit scanning operation for monochrome mode is performed once is After sub-scanning at a relative position that coincides with the main scan line at the lower end of the monochrome area, all the nozzles of the achromatic nozzle group are used for monochrome area. While forming a main scanning line dot on, performed once a unit scan operation for monochrome mode, then it is preferable to shift to color mode printing.

  In such an embodiment, in a predetermined case, alignment feed is performed at the end of monochrome mode printing, and main scanning lines are recorded by the nozzles of the achromatic nozzle group. In such a mode, in monochrome mode printing, when monochrome mode sub-scanning is performed, the monochrome area is more efficiently compared to printing in which the nozzle reaches the color area and then shifts directly to color mode printing. Printing can be performed.

  In monochrome mode printing, when it is assumed that color mode sub-scanning is performed next, if the main scanning line at the lower end of the achromatic unit band is located in the color area, the mode may be shifted to color mode printing. preferable. With such an aspect, it is possible to efficiently shift from monochrome mode printing to color mode printing.

  Also, in monochrome mode printing, the number of main scanning lines Lr1 in the remaining monochrome area, which is an area where there is a main scanning line that has not yet been recorded in the monochrome area, is not obtained in a single monochrome mode unit scan operation. The chromatic nozzle group is smaller than the number of main scanning lines L1 of the achromatic unit band, which is a bundle of main scanning lines that can be recorded without gaps in the sub-scanning direction, and a single chromatic color is obtained by a single color mode unit scanning operation. When one of the nozzle groups is larger than the number L2 of main scanning lines of a single chromatic unit band that is a bundle of main scanning lines that can be recorded without gaps in the sub-scanning direction, it is assumed that the unit scanning operation for monochrome mode is performed once. Relative position so that the main scan line at the bottom of the achromatic unit band matches the main scan line at the bottom of the monochrome area After performing the sub-scan, the unit scan operation for monochrome mode is performed once while forming dots on the main scan line of the monochrome area using all the nozzles of the achromatic nozzle group, and then the color mode It is preferable to shift to printing. According to such an aspect, the time required for printing can be shortened by performing alignment feeding based on a simple determination criterion.

  In monochrome mode printing, when the number of main scanning lines Lr1 of the remaining monochrome area is smaller than the number of main scanning lines L1 of the achromatic unit band and the number of main scanning lines L2 of the single chromatic unit band, the color mode It is preferable to shift to printing. With such an aspect, it is possible to efficiently shift from monochrome mode printing to color mode printing without performing complicated processing.

  The plurality of single chromatic color nozzle groups each include C nozzles (N is an integer of 2 or more) including N nozzles (N is an integer of 2 or more) arranged at a nozzle pitch k × D in the sub-scanning direction. ), And the achromatic nozzle group is a nozzle row composed of N × C nozzles arranged at a nozzle pitch k × D in the sub-scanning direction, the following sub-scan is performed: Preferably it is done. That is, let D be the first feed amount and the third feed amount. The second feed amount is N × C × k × D. The fourth feed amount is N × k × D. According to such an aspect, the main scanning lines recorded by the unit scanning operation are adjacent to each other. This facilitates the mode transition process between color mode printing and monochrome mode printing.

  The first feed amount and the third feed amount may be m × D (m is an integer between 2 and k and a prime number). In such a case, the second feed amount is set to a bundle of main scanning lines that are recorded in the unit scan operation for the previous monochrome mode and are arranged without gaps in the sub-scanning direction. A feed amount for performing sub-scanning at a relative position such that the upper end nozzle of the achromatic nozzle group is positioned on the main scan line immediately below the lower main scan line. The fourth feed amount is a bundle of main scanning lines that have been recorded in the immediately preceding color mode unit scan operation and is a main scanning line at the lower end of a bundle of main scanning lines that are arranged without gaps in the sub-scanning direction. A feed amount for performing sub-scanning is set at a relative position where the uppermost nozzle among the nozzles of the plurality of single chromatic color nozzle groups is positioned on the main scanning line immediately below the scanning line. With such an aspect, the interlaced printing is partially performed, so that the quality of the printing result is improved.

  In addition, when printing is performed on a monochrome area recorded using only achromatic ink and a color area recorded using chromatic ink on the printing medium, the following printing can also be performed. That is, in main scanning, a specific achromatic nozzle group that is a part of the achromatic nozzle group and includes the same number of nozzles as the single chromatic nozzle group and a plurality of single chromatic nozzle groups, and at least the color A dot is formed on the main scanning line of the area, and a unit scan operation for color mode configured by k1 main scanning and (k1-1) subscanning with a predetermined first feed amount is performed in a predetermined manner. Color mode printing is performed in which color mode sub-scanning with the second feed amount is repeated while performing each color mode unit scan operation.

  Also, in the main scanning, dots are formed on the main scanning line in the monochrome area using all the nozzles of the achromatic nozzle group without using the nozzles of the single chromatic nozzle group, and k2 times of main scanning. And a monochrome mode unit scan operation consisting of (k2-1) sub-scans with a predetermined third feed amount, and a monochrome mode sub-scan with a fourth feed amount greater than the second feed amount. The monochrome mode printing is executed, which is repeatedly performed while performing the unit scan operation for each monochrome mode.

  Then, in color mode printing, when a predetermined condition is satisfied, the mode is shifted to monochrome mode printing. Even in such an aspect, high quality printing can be performed in each of the monochrome area and the color area. Then, it is possible to efficiently shift from monochrome mode printing to color mode printing.

  A plurality of single chromatic color nozzle groups is a nozzle row including N (N is an integer of 2 or more) nozzles each arranged at a nozzle pitch k1 × D in the sub-scanning direction. When the nozzle row is composed of N × p nozzles (p is an integer of 2 or more) arranged at a nozzle pitch k2 × D in the sub-scanning direction, it is preferable to perform the following sub-scanning. That is, the first feed amount is m1 × D (m1 is 1 or more and a prime integer of k2). The second feed amount is {N × k1-m1 × (k1-1)} × D. The third feed amount is m2 × D (m2 is 1 or more and a prime integer of k1). And let the 4th feed amount be {N * p * k2-m2 * (k2-1)} * D. In this mode, dots can be efficiently recorded on each adjacent main scanning line in each mode.

  In color mode printing as described above, when it is assumed that color mode sub-scanning is performed next, a plurality of single chromatic color nozzle groups can newly complete recording in one color mode unit scan operation. When all the main scanning lines of the color unit band, which are bundles of main scanning lines and are arranged in the sub scanning direction without gaps, are located in the monochrome area, it is preferable to shift to monochrome mode printing. .

  According to such an aspect, the color mode printing can be efficiently transferred from the monochrome mode printing by recording the monochrome region main scanning line together with the color region main scanning line in the color mode printing. .

Note that the present invention can be realized in various modes as described below.
(1) Printing method and printing control method.
(2) Printing device and printing control device.
(3) A computer program for realizing the above apparatus and method.
(4) A recording medium on which a computer program for realizing the above apparatus and method is recorded.
(5) A data signal embodied in a carrier wave including a computer program for realizing the above-described apparatus and method.

Next, embodiments of the present invention will be described in the following order based on examples.
A. First embodiment:
A1. Device configuration:
A2. printing:
B. Second embodiment:
C. Third embodiment:
D. Variations:

A. First embodiment:
A1. Device configuration:
FIG. 1 is a schematic configuration diagram of a printing system including an inkjet printer 20 as an embodiment of the present invention. The printer 20 includes a main scanning feed mechanism that causes the carriage 30 to reciprocate along the slide shaft 34 by the carriage motor 24, and a direction perpendicular to the main scanning direction by the paper feed motor 22 (“sub-scanning direction”). )), A head drive mechanism for controlling the ink ejection and dot formation by driving the print head unit 60 mounted on the carriage 30, the paper feed motor 22, and the carriage motor. 24, a control circuit 40 that controls the exchange of signals with the print head unit 60 and the operation panel 32. The control circuit 40 is connected to the computer 88 via the connector 56.

  The sub-scan feed mechanism that transports the printing paper P includes a gear train (not shown) that transmits the rotation of the paper feed motor 22 to a paper transport roller (not shown). The main scanning feed mechanism that reciprocates the carriage 30 includes a slide shaft 34 that is laid in a direction perpendicular to the conveyance direction of the printing paper P and that slidably holds the carriage 30, and the carriage 30 and the carriage motor 24. A pulley 38 that stretches an endless drive belt 36 therebetween, and a position sensor 39 that detects the origin position of the carriage 30 are provided.

  FIG. 2 is a block diagram showing the configuration of the printer 20 with the control circuit 40 as the center. The control circuit 40 is configured as an arithmetic and logic circuit including a CPU 41, a programmable ROM (PROM) 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 dedicated to interface with an external motor and the like, and a head that is connected to the I / F dedicated circuit 50 and drives the print head unit 60 to eject ink. A drive circuit 52 and a motor drive circuit 54 for driving the paper feed motor 22 and the carriage motor 24 are provided. The I / F dedicated circuit 50 incorporates a parallel interface circuit and can receive a print signal PS supplied from the computer 88 via the connector 56. The CPU 41 functions as a color mode unit 41a and a monochrome mode unit 41b, which will be described later, by executing a computer program stored in the PROM 42.

  The print head 28 includes a plurality of nozzles n provided in a line for each color, and an actuator circuit 90 that operates the piezoelectric element PE provided in each nozzle n. The actuator circuit 90 is a part of the head drive circuit 52 (see FIG. 2), 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 90 latches data indicating ON (discharges ink) or OFF (does not discharge ink) for each nozzle in accordance with the print signal PS supplied from the computer 88, and drives only the ON nozzle. A signal is applied to the piezo element PE.

  FIG. 3 is an explanatory diagram showing the arrangement of nozzles provided in the print head 28. The printer 20 is a printing apparatus that performs printing using four color inks of black (K), cyan (C), magenta (M), and yellow (Y), and includes cyan (C), magenta (M), Yellow (Y) is provided with two nozzles, and black (K) is provided with six nozzles. Cyan (C), magenta (M), and yellow (Y) nozzles # 1 and # 2 correspond to a “single chromatic nozzle group” in the claims. The black (K) nozzles # 1 to # 6 correspond to the “achromatic nozzle group” in the claims.

  The actuator circuit 90 drives the actuator chips 91 to 93 that drive the black nozzle row K, the actuator chip 94 that drives the cyan nozzle row C, the actuator chip 95 that drives the magenta nozzle row M, and the yellow nozzle row Y. An actuator chip 96 is provided.

  The print head 28 is reciprocated along the slide shaft 34 in the direction of the arrow MS by the carriage motor 24. Then, the printing paper P is fed to the printing head 28 by the paper feed motor 22 in the direction of the arrow SS.

A2. printing:
(1) Color mode printing and monochrome mode printing:
FIG. 4 is an explanatory diagram showing the recording of the main scan line by the unit scan operation during monochrome mode printing. FIG. 5 is an explanatory diagram showing the recording of the main scan line by the unit scan operation during color mode printing. The arrangement of the nozzles is schematically shown on the left side of each figure, and the manner in which the main scanning line is recorded by each nozzle is shown on the right side. Actually, the print paper P is transported with respect to the print head and the relative position of the two changes, but here, for the sake of simplicity of explanation, the print head is moved downward with respect to the print paper P. As you can see. Note that the numbers indicated by # in the squares are the numbers of the nozzles that record each main scanning line. Further, in this specification, when describing the recording of each main scanning line, the direction of the front end when the printing paper P is fed by the paper feed motor 22 is referred to as “upward”, and the direction of the tail end is referred to as “downward”. "

  Each main scanning line is a column of pixels extending in the left-right direction in FIG. The interval between main scanning lines adjacent in the vertical direction is D. As can be seen from FIG. 4, the vertical pitch (sub-scanning direction) of each nozzle on the print head is 4 × D. In this specification, the interval between adjacent main scanning lines is expressed as “1 dot”. Therefore, the pitch of each nozzle on the print head is 4 dots. Further, when the feed amount of the sub-scan feed is described, it is expressed in “dot” units with the interval between the main scan lines as a reference. In the first embodiment, the nozzle pitch is 4 dots, but the nozzle pitch may be other values such as 6, 8. That is, the nozzle pitch k [dot] may be an integer of 2 or more.

  In printing in the first embodiment, a unit scan operation is performed in which fine feed (sub-scan) is performed by one dot between each main scan to perform k main scans. By this unit scan operation, dots are recorded in a band composed of a plurality of main scan lines adjacent in the sub-scanning direction. Then, a large feed is performed between the unit scan operation and the unit scan operation, and recording is performed in units of a bundle of main scan lines on the printing paper in order. In the first embodiment, as shown in FIGS. 4 and 5, one unit scan operation is completed by repeating the one-dot feed three times and performing four main scans. One main scan is called “pass”.

  As shown in FIG. 4, the main scan lines recorded by the black ink when the unit scan operation is performed using all the nozzles of the black nozzle group K, and the main scans are arranged without gaps in the sub-scan direction. The number of lines L1 is 24. A set of main scanning lines recorded by black ink when a unit scanning operation is performed using all the nozzles of the black nozzle group K is called an “achromatic unit line”, of which the sub-scanning direction is A bundle of main scanning lines arranged without gaps is called an “achromatic unit band”. In the first embodiment, the “achromatic unit line” and the “achromatic unit band” match. In monochrome mode printing in which the unit scan operation is performed using all nozzles of the black nozzle group K, after one unit scan operation is completed, the sub scan corresponding to 21 main scan lines is performed in order to perform the next unit scan operation. A scan is performed. This sub-scanning is called “monochrome mode sub-scanning”. The monochrome mode sub-scan feed amount Sm is 21 dots. Assuming that the number of black nozzle group nozzles is (N × p), the nozzle pitch is k2 dots, and the amount of feed performed between main scans in line recording is m1 dots { N * p * k2-m * (k2-1)} * D.

  Note that “use (all) nozzles” means that the nozzles can be used in printing in that mode. Therefore, depending on the contents of the sent print data, the nozzle may not actually be used. Also, if a nozzle that ejects the same color ink passes over the main scan line that has already been recorded with the ink of a certain color for the convenience of sub-scanning, that nozzle is not actually used. There is also. In addition to image data, the print data includes assumed pixel pitch data, sub-scan feed amount data, and the like. In the description of the present invention, the term “image” includes all forms of objects to be recorded on a print medium such as characters, symbols, and diagrams in addition to pictures.

  On the other hand, in color mode printing, printing is performed using the same number of nozzles for each ink color. For this reason, only two nozzles, nozzles # 5 and # 6, are used as the nozzles of the black nozzle group K. Black nozzles used in color mode printing are referred to as “specific black nozzle group K0”.

  As shown in FIG. 5, when the unit scan operation is performed using the single chromatic nozzle groups Y, M, and C and the specific black nozzle group K0, the main scan recorded by the ink ejected from each nozzle group is performed. The numbers L2 of lines (referred to as “single chromatic color unit bands”) are 8 respectively. The same applies to the specific black nozzle group K0. Therefore, in color mode printing, after one unit scan operation is completed, sub-scanning for five main scan lines is performed before the next unit scan operation is performed. This sub-scanning is called “color mode sub-scanning”. The color mode sub-scan feed amount Sc is 5 dots. The feed amount for the sub-scan for the color mode is {N if the number of nozzles of the single chromatic nozzle group is N, the nozzle pitch is k1 dots, and the feed amount performed between main scans in line recording is m2 dots. * K1-m2 * (k1-1)} * D.

  When focusing on the 17th to 24th lines in FIG. 5, first, in the first unit scan operation, the nozzles # 5 and # 6 of the specific black nozzle group K0 and the cyan nozzle group are displayed on the 17th to 24th lines. A dot is formed by C. Thereafter, when color mode sub-scanning for five main scanning lines is performed, magenta dots are recorded on the 17th to 24th lines by the magenta nozzle group M this time. Further, when color mode sub-scanning for five main scanning lines is performed, yellow dots are recorded by the yellow nozzle group Y on the 17th to 24th lines. Thus, black, cyan, magenta and yellow dots are formed on the 17th to 24th lines, and a color image is recorded. Each main scanning line on the printing paper is similarly recorded in order by three unit scanning operations.

  In FIG. 5, the recording of each main scanning line by the nozzles # 5 and # 6 of the specific black nozzle group is not shown for the sake of simplicity. The recording of the main scanning lines of the black nozzles # 5 and # 6 is performed in the same manner as the recording of the main scanning lines by the cyan nozzles # 1 and # 2.

  When a unit scan operation is performed using the single chromatic color nozzle group Y, M, C and the specific black nozzle group K0, and the color mode sub-scan is performed between the unit scan operations, that is, in the case of color mode printing think of. In color mode printing, the main scanning line where the yellow nozzle group Y has finished recording in each unit scan operation is the main scanning line where printing of print data for all inks of KCMY has been completed. That is, data recording is newly completed on the main scan line by 8 lines in each unit scan operation. A set of main scanning lines in which a plurality of single chromatic color nozzle groups can newly complete printing in one unit scanning operation is called a “color unit line”. Of the color unit lines, the main scanning lines arranged without gaps in the sub-scanning direction are referred to as “color unit bands”. In the first embodiment, the “color unit line” and the “color unit band” match. The width of the color unit band is equal to the width of the single chromatic unit band. The color unit band usually coincides with the single chromatic color band of the uppermost single chromatic nozzle group.

  Note that color mode printing is executed by the color mode unit 41a, and monochrome mode printing is executed by the monochrome mode unit 41b (see FIG. 2).

(2) Transition from color mode printing to monochrome mode printing 1:
FIG. 6 is a flowchart showing processing in color mode printing. FIG. 7 is an explanatory diagram showing how image data including a color area and a monochrome area is recorded. The image data to be printed includes a chromatic area and an achromatic area. As a result, a color area and a monochrome area corresponding to the chromatic area and the achromatic area of the image data also exist on the printing paper on which the image is printed. The color area is an area recorded using at least chromatic ink. In the first embodiment, black ink is also used for color area recording. The monochrome area is an area recorded with only achromatic ink. In the first embodiment, only black ink is used for recording in the monochrome area.

  In FIG. 7, main scanning lines (four in this case) recorded by one nozzle in one unit scanning operation are schematically represented by an array of squares in the horizontal direction. For example, the top row represents the first to fourth lines recorded by the yellow nozzle # 1 in the first unit scan operation. In the example of FIG. 7, the 45th to 156th lines are monochrome areas, and the upper side from the 44th line and the lower side from the 157th line are color areas. In FIG. 7, as also shown in the upper right of the drawing, the print head that executes the unit scan operation is schematically represented by a grid of 2 columns × 6 rows. One column corresponds to an actual nozzle column (see FIGS. 4 and 5), and an area corresponding to the width of four main scanning lines recorded by each nozzle in one unit scan operation is represented by one row. Represents. K, C, M, and Y in each square represent the color of ink ejected by each nozzle. Actually, the print paper P is transported with respect to the print head, and the relative position of the two changes, but in order to simplify the explanation in FIG. 7, the print head represented by a 2 × 6 cell is shown below. It is displayed as if it moves downward relative to the printing paper P. For nozzles that are not actually used in each main scan, K, C, M, and Y are not written in the cells corresponding to each nozzle.

  In color mode printing, in step S22 in FIG. 6, it is assumed that the color mode sub-scan is performed next (here, it corresponds to the single chromatic color band of the nozzles of the yellow nozzle group). The main scanning lines are considered. As a result, when it is determined in step S24 that there is a color line (referred to as a main scanning line included in the color area, the same applies hereinafter), color mode sub-scanning is performed in step S26, and two colors are selected in step S28. Unit scan operation is performed using each nozzle. In the example of FIG. 7, printing up to the 24th pass is executed according to this routine.

  That is, in color mode printing, as long as the color unit main scan line is included in the color unit band when the color mode sub-scan is performed next, steps S26 and S28 are repeated, and color mode printing is performed. Executed. At this time, if the print head is at a relative position that spans both the color area and the monochrome area, the main scan line of the monochrome area is also recorded by the specific black nozzle group K0. In the example of FIG. 7, the 45th to 64th lines are recorded as such.

  In the case of color mode printing, when a monochrome line is included in a unit line or unit band recorded by performing a predetermined sub-scan that is considered next and a subsequent unit scan operation. The considered unit lines and the main scanning line at the lower end of the unit band are considered to be located in the monochrome area. When such a unit line or unit band does not include a monochrome line, the main scanning line at the lower end of the unit line or unit band is considered to be located in the color area.

  On the other hand, if it is determined in step S24 that there is no color line, that is, if the main scanning lines of the color unit band when the color mode sub-scanning is performed next are all located in the monochrome area, color Transition from mode printing to monochrome mode printing. Note that after shifting to monochrome mode printing, first, monochrome mode sub-scanning is performed. In the example of FIG. 7, the sub-scan performed after the 24th pass is the first sub-scan after shifting to the monochrome mode printing according to this routine, and the unit scan operation including the 25th to 28th passes is the monochrome mode. This is the first unit scan operation after shifting to printing.

  At the time after the 24th pass, the main scanning lines (45th to 64th lines) above the monochrome area have already been recorded by the specific black nozzle group K0 during the 13th to 24th passes. On the other hand, in monochrome mode printing, all the nozzles of the black nozzle group K are used. Therefore, even when the monochrome mode sub-scan is performed after the 24th pass and the next unit scan operation (25th to 28th passes) is performed, the main scan lines in the monochrome area can be recorded without any gaps. Note that the transition from the color mode printing to the monochrome mode printing is executed by the transition unit 41a1 (see FIG. 2) of the color mode unit 41a.

(3) Transition from color mode printing to monochrome mode printing 2:
FIG. 8 is a block diagram illustrating another aspect of the control circuit of the printer 20. The CPU 41 of the control circuit 40s shown in FIG. 8 functions as a color mode unit 41a and a monochrome mode unit 41b, like the CPU 41 of the control circuit 40 shown in FIG. However, the color mode unit 41a of the control circuit 40s shown in FIG. 8 further includes a first transition unit 41a2 and a second transition unit 41a3 as functional units. The control circuit 40s shown in FIG. 8 is the same as the control circuit 40 shown in FIG. In a printer having a control circuit having such a configuration, it is possible to shift from color mode printing to monochrome mode printing in the following manner.

  9 and 10 are flowcharts showing processing in color mode printing. FIG. 11 is an explanatory diagram showing how image data including a color area and a monochrome area is recorded. In color mode printing, it is assumed in step S23 in FIG. 9 that the unit scan operation is performed by performing color mode sub-scanning next, and the main scanning line (“specific non-specified” recorded by the specific black nozzle group K0 is assumed. What main scanning line is included in “coloring unit line”) is examined. As a result, if it is determined in step S25 that there is no monochrome line (referred to as a main scanning line included in the monochrome area; the same applies hereinafter), color mode sub-scanning is performed in step S27, and two colors are selected in step S29. Unit scan operation is performed using each nozzle. In the example of FIG. 11, printing up to the 12th pass is executed according to this routine.

  In the case of color mode printing, when a monochrome line is included in a unit line or unit band recorded by performing a predetermined sub-scan that is considered next and a subsequent unit scan operation. The considered unit lines and the main scanning line at the lower end of the unit band are considered to be located in the monochrome area. When such a unit line or unit band does not include a monochrome line, the main scanning line at the lower end of the unit line or unit band is considered to be located in the color area.

  On the other hand, if it is determined in step S25 that there is a monochrome line, it is assumed in step S31 what main scanning is performed on the color unit line when it is assumed that the unit mode operation is performed by performing the color mode sub-scanning next. Consider whether the line is included. As a result, when it is determined in step S33 that there is a color line (referred to as a main scanning line included in the color area; the same applies hereinafter), in step S35, among the nozzles of the specific black nozzle group K0, Mask nozzles that pass through. In step S27, color mode sub-scanning is performed. In step S29, a unit scanning operation is performed. In the example of FIG. 11, printing from the 13th to the 24th pass is executed according to this routine. In the figure, the nozzles marked with “*” are nozzles masked in step S35. Note that such transition processing from color mode printing to monochrome mode printing is performed by the first transition unit 41a2 (see FIG. 8) of the color mode unit 41a.

  If it is determined in step S33 that there is no color line in the next color unit line, alignment feed is performed in step S37 of FIG. In this alignment feed, the main scan line at the upper end of the achromatic unit band when the unit scan operation is performed using all the nozzles of the black nozzle group coincides with the main scan line at the upper end of the monochrome area. It is performed so that it may become a relative position. Thereafter, in step S39, the unit scan operation is performed using all the nozzles of the black nozzle group, and the mode is shifted to the monochrome mode. In the example of FIG. 11, the sub-scan feed after the 24th pass is the alignment feed in step S37. In the example of FIG. 11, the feed amount Sc1 of the alignment feed is 4 dots. The unit scan operation including the 25th to 28th passes is the unit scan operation performed in step S39. Note that the transition from the color mode printing to the monochrome mode printing is executed by the second transition unit 41a3 (see FIG. 8) of the color mode unit 41a.

  That is, in color mode printing, as long as the color unit main scanning line is included in the color unit line when the color mode sub-scanning is performed next, steps S27 and S29 are repeated, and color mode printing is performed. Executed. At this time, if the nozzle of the specific black nozzle group K0 is in the monochrome area, the gap is masked (step S35), and the main scan line in the monochrome area is not recorded. In the example of FIG. 11, in the 13th to 24th passes, the black nozzles pass on the 45th to 64th lines, but these black nozzles are masked and the 45th to 64th lines are not recorded.

  Thereafter, when the color unit main scanning line is not included in the color unit line when the color mode sub-scanning is performed next (step S33 in FIG. 9), alignment feeding is performed (step S37). . In the example of FIG. 11, since the achromatic color unit line and the achromatic color unit band coincide with each other, the sub-scan is performed so that the nozzle at the upper end of the black nozzle group K is positioned at the position of the 45th line that is the upper end of the monochrome area. Is done. Thereafter, a unit scan operation is performed using all the nozzles of the black nozzle group K (step S39), and then monochrome mode printing is performed.

  With such an embodiment, the number of times of color mode sub-scanning, monochrome mode sub-scanning, and alignment feeding when recording the portion near the upper end of the monochrome area in contact with the color area can be reduced. For example, in FIG. 11, when the 45th to 64th lines are recorded by the nozzles marked with “*” in the 13th to 24th passes, the 45th to 64th lines in the monochrome region are two times in between. Recording is performed by three unit scan operations with the color mode sub-scan interposed therebetween. On the other hand, in the mode of FIG. 11, the 45th to 64th lines are recorded by one unit scan operation of 24th to 28th passes. Since the color mode sub-scan, monochrome mode sub-scan, and alignment feed have a larger feed amount than the minute feed (see FIGS. 4 and 5) performed in the unit scan operation, the feed error also increases. Therefore, as the number of times of feeding when the same area is printed increases, the quality of the print result is likely to deteriorate. In the first embodiment, since the number of times of these feeds can be reduced, the quality of the print result of the portion near the boundary with the color area in the monochrome area where the upper end is in contact with the color area can be increased. .

(4) Transition from monochrome mode printing to color mode printing 1:
FIG. 12 is a flowchart showing processing in monochrome mode printing. In monochrome mode printing, in step S42, it is examined what main scanning line is included in the achromatic unit band when it is assumed that monochrome mode sub-scanning is performed next. As a result, if it is determined in step S44 that there is no color line, the monochrome mode sub-scan is performed in step S46, and the unit scan operation is performed using all the nozzles of the black nozzle group K in step S48. Thereafter, the process returns to step S42. In FIG. 7, the printing up to the 36th pass after the sub-scan performed after the 24th pass is executed according to this routine.

  That is, in monochrome mode printing, steps S46 and S48 are repeated and monochrome mode printing is executed unless the main scanning line of the color area is included in the achromatic unit band when the monochrome mode sub-scan is performed next. Is done.

  In monochrome mode printing, when a color line is included in a unit line or unit band that is recorded by performing a predetermined sub-scan that is being considered next and a subsequent unit scan operation. Therefore, it is considered that the main scanning line at the lower end of the unit line or unit band examined is located in the color region. When such a unit line or unit band does not include a color line, the main scanning line at the lower end of the unit line or unit band is considered to be located in the monochrome area.

  If it is determined in step S44 that there is a color line, in step S50, it is examined what main scanning line is included in the achromatic unit band when it is assumed that the color mode sub-scan is performed next. To do.

  If it is determined in step S52 that there is no color line, in step S54, alignment is performed at a relative position such that the main scanning line at the lower end of the achromatic unit band matches the main scanning line at the lower end of the monochrome area. Feed. In step S56, the unit scan operation is performed using all the nozzles of the black nozzle group K. However, in step S56, the width (number of main scanning lines) of the area where black dots are to be recorded is smaller than the number of main scanning lines L1 of the achromatic unit band. , Not used in some or all main scans. In FIG. 7, the sub-scan performed after the 36th pass and the unit scan operations of the 37th to 40th passes are executed according to this routine. Here, the feed amount Sm1 of the alignment feed is 20 dots. Thereafter, the process shifts to color mode printing. Note that after shifting to color mode printing, color mode sub-scanning is first performed. The sub-scan performed after the 40th pass is the first sub-scan after shifting to color mode printing.

  That is, in monochrome mode printing, it is assumed that the main scanning line at the lower end of the achromatic unit band is located in the color area when it is assumed that monochrome mode sub-scanning is performed next, and for monochrome mode printing. When it is assumed that color mode sub-scanning is performed instead of sub-scanning, and the main scanning line at the lower end of the achromatic unit band is located in the monochrome area, (1) a predetermined alignment feed is performed, 2) After the unit scan operation is performed while forming dots on the main scan line in the monochrome area, (3) the mode shifts from monochrome mode printing to color mode printing. In the alignment feed, the main scan line at the lower end of the achromatic unit band is assumed to be the main scan at the lower end of the monochrome area when it is assumed that the relative position between the print head and the printing paper is one unit scan operation after the sub-scan. This is performed so that the relative position coincides with the line. Note that the transition from the monochrome mode printing to the color mode printing is executed by the first transition unit 41b1 (see FIG. 2) of the monochrome mode unit 41b.

  In the first embodiment, in the above case, alignment feed is performed, and the unit scan operation is performed using all the nozzles of the black nozzle group K. Then, the feed amount Sm of the alignment feed is larger than the feed amount Sc of the color mode sub-scan. For this reason, by performing alignment feeding, it is possible to perform printing more efficiently than in the case of directly shifting to color mode printing and recording the main scanning lines of the remaining monochrome area with the specific black nozzle group K0. .

  FIG. 13 is an explanatory diagram of another example showing how image data including a color area and a monochrome area is recorded. The print data shown in FIG. 13 is the same as that shown in FIG. 7 except that the area above the 140th line is a monochrome area and the area below the 141st line is a color area. Therefore, the processing of each pass is the same as that in FIG. 7 up to the 36th pass. In the example of FIG. 13, as shown in the lower left of the figure, the lower end of the achromatic unit band is positioned in the color area even if the color mode sub-scan is performed after the 36th pass. Therefore, it is determined that there is a color line in step S52 of FIG. In this case, the process proceeds to color mode printing as it is. Note that after shifting to color mode printing, color mode sub-scanning is first performed. In FIG. 13, the sub-scan performed after the 36th pass is the first sub-scan after shifting to the color mode printing according to this routine, and the unit scan operation including the 37th to 40th passes is performed in the color mode printing. This is the first unit scan operation.

  That is, in monochrome mode printing, even if it is assumed that color mode sub-scanning is performed next, if the main scanning line at the lower end of the achromatic unit band is located in the monochrome area, the process proceeds to color mode printing as it is. . Note that the transition from the monochrome mode printing to the color mode printing is performed by the second transition unit 41b2 (see FIG. 2) of the monochrome mode unit 41b. The first transition unit 41b1 and the second transition unit 41b2 constitute a transition unit 41b0 of the monochrome mode unit 41b.

  In the first embodiment, since the processing as shown in the lower part of FIG. 13 is performed, when shifting from the monochrome mode printing to the color mode printing, the color mode printing is efficiently performed without performing an extra alignment feed. Can be migrated.

(5) Transition from monochrome mode printing to color mode printing 2:
FIG. 14 is a flowchart illustrating another example of monochrome mode printing. In the flowchart of FIG. 14, step S43 is executed instead of steps S42 and S44 of FIG. 12, and step S51 is executed instead of steps S50 and S52 of FIG. Other points are the same as those in the flowchart of FIG. Processing in monochrome mode printing can also be performed as follows.

  First, in step S43, the number of main scanning lines Lr1 of the remaining monochrome area, which is the main scanning line of the monochrome area currently recorded and has not yet been recorded, and the achromatic unit band. The number L1 of main scanning lines is compared. If the number Lr1 of main scanning lines in the remaining monochrome area is larger than the number L1 of main scanning lines in the achromatic unit band, steps S46 and S48 are executed to perform monochrome mode printing.

  If it is determined in step S43 that the number of main scanning lines Lr1 in the remaining monochrome area is equal to or less than the number L1 of main scanning lines in the achromatic unit band, in step S51, the number of main scanning lines Lr1 in the remaining monochrome area is The number L2 of main scanning lines in one chromatic unit band is compared. When the number Lr1 of main scanning lines in the remaining monochrome area is greater than or equal to the number L2 of main scanning lines in a single chromatic unit band, alignment feed is performed in step S54. If the number Lr1 of main scanning lines in the remaining monochrome area is smaller than the number L2 of main scanning lines in a single chromatic color unit band, the process proceeds to the color mode as it is.

  Even if such processing is performed, printing as shown in FIGS. 7 and 13 is appropriately performed. With such processing, it is possible to shift from monochrome mode printing to color mode printing with simpler processing. 7 and 13, for comparison, the number L1 of the main scanning lines of the achromatic unit band and the number L2 of the main scanning lines of the single chromatic unit band of each single chromatic nozzle group are shown on the upper right. Is shown.

B. Second embodiment:
(1) Color mode printing and monochrome mode printing:
FIG. 15 and FIG. 16 are explanatory diagrams showing the arrangement of the nozzles of the printer of the second embodiment and the recording of the main scan line by the unit scan operation. Also in the printer of the second embodiment, the nozzles provided in the print head are arranged with a pitch k of 4 in the sub-scanning direction. However, in the printer of the second embodiment, the black nozzle group K has 15 nozzles arranged in a line in the sub-scanning direction. Each single chromatic nozzle group C, M, Y has five nozzles arranged in a line in the sub-scanning direction. Of the black nozzle group K, specific black nozzle groups K0 used in color mode printing are nozzles # 11 to # 15. Other points are the same as those of the printer of the first embodiment. Further, in the second embodiment, as shown in FIGS. 15 and 16, one unit scan operation is completed by repeating the 3-dot feed three times and performing four main scans. As described above, by adopting a feed amount of 4 [dots] and 3 [dots] which is a prime, it is possible to record various scan lines without gaps by repeating the unit scan operation. The three-dot feed amount performed in the unit scan operation of monochrome mode printing shown in FIG. 15 is the “first feed amount” in the claims. The three-dot feed amount performed in the unit scan operation of color mode printing shown in FIG. 16 is the “third feed amount” in the claims.

  In the second embodiment, since 3 dots are fed, the main scanning lines recorded by the unit scan operation are not all in contact with each other. Referring to FIG. 15, the first line, the fourth and fifth lines, and the seventh line are recorded by one unit scan operation, but the second and second lines between the first line and the fourth line are recorded. Three lines are not recorded in the unit scan operation. Also, the sixth line between the fifth line and the seventh line is not recorded in the unit scan operation. For this reason, in the second embodiment, the achromatic unit lines are the 60 main scanning lines from the first to the 66th lines in FIG. 15, but the achromatic unit band is the seventh to the 60th lines. Up to 54 main scanning lines. Therefore, the main scanning line number L1 of the achromatic unit band recorded by the black nozzle group K is 54 lines. On the upper side and the lower side of the achromatic unit band, there are main scanning lines recorded by the same unit scanning operation as the achromatic unit band with the main scanning line not recorded by the unit scanning operation interposed therebetween. These main scanning lines are also included in the achromatic unit line.

  FIG. 17 is an explanatory diagram showing the recording of the main scanning line during monochrome mode printing by the printer of the second embodiment. In FIG. 17, in the fourth pass, which is the last pass of the first unit scan operation, nozzle # 1 is at the position of the 10th line. In monochrome mode printing, in the fifth pass, which is the first pass of the next unit scan operation, nozzle # 1 comes to the position of the 61st line that was not recorded in the previous unit scan operation. That is, the feed amount Sm of the monochrome mode sub-scan is 51 dots. This monochrome mode sub-scan is a main scan line at the lower end of a bundle of main scan lines recorded in the immediately preceding unit scan operation and arranged in the sub-scan direction without gaps (FIG. 15). This is performed so that the nozzle at the upper end of the black nozzle group K is positioned in the main scanning line (61st line) immediately below the 60th line. By performing such monochrome mode sub-scanning, each main scan line is recorded without gaps in monochrome mode printing.

  Assuming that the nozzle pitch of the black nozzle group K used in monochrome mode printing is k2 × D (D is the main scanning line pitch. K2 is an integer of 2 or more), as shown in FIGS. 15 and 17, the unit scanning operation is performed. The number of main scans performed in the unit scan operation is k2, and the number of sub-scans performed in the unit scan operation is (k2-1). Further, the sub-scan feed amount Sum performed in the unit scan operation can be expressed as follows.

  Sum = m1 × D (1)

  Here, m1 may be an integer that is 2 or more and prime with k. However, it is preferable that it is the smallest number or the second smallest number among integers that are prime and equal to or larger than 2. This is because the smaller the m1, the smaller the unprintable area. This point will be described later. In the monochrome mode printing of the third embodiment, m1 is 3. This is the smallest number among integers that are prime and equal to or larger than 2.

  Further, when the number of nozzles is N × p (N is the number of nozzles of a single chromatic color nozzle group. P is a positive integer. In the second embodiment, it is 3). Sm is represented by the following equation.

Sm = N × p × k2 × D-Sum × (k2-1)
= {N * p * k2-m1 * (k2-1)} * D (2)

  FIG. 18 is an explanatory diagram showing the recording of the main scanning line during monochrome mode printing by the printer of the second embodiment. FIG. 17 shows seven passes after the start of printing, whereas FIG. 18 shows eight passes before the end of printing. As shown in FIG. 17, in the monochrome mode printing of the second embodiment, among the areas on the printing paper on which the nozzles are arranged at the start of printing, the first to sixth lines at the upper end are the non-printable areas. . As shown in FIG. 18, among the areas on the printing paper on which the nozzles are arranged at the end of printing, the sixth line from the bottom from the bottom line is also a non-printable area.

  19 and 20 are explanatory diagrams showing recording of main scanning lines according to a comparative example. FIG. 19 shows five passes after the start of printing, and FIG. 20 shows five passes before the end of printing. In this comparative example, interlaced printing that repeats 15-dot sub-scanning is performed in a printing apparatus having the same hardware configuration as that of the second embodiment. When interlaced printing is performed, as shown in FIGS. 19 and 20, the unprintable area is 42 lines on both the upper end side and the lower end side.

  In the monochrome mode printing of the second embodiment, printing that repeats the unit scan operation is performed instead of interlaced printing. For this reason, as shown in FIGS. 17 and 19, and FIGS. 18 and 20, the non-printable area is significantly smaller in the second embodiment than in the comparative example. Furthermore, in the monochrome mode printing of the second embodiment, the sub-scan feed amount m1 dot performed in the unit scan operation is the minimum number among the integers that are prime and 2 or more of the nozzle pitch k2. It is a dot. Therefore, the printing impossible area is the smallest in the printing in which the unit scanning operation with the feeding amount Sum of 2 or more is performed.

  FIG. 21 is an explanatory diagram showing the recording of the main scanning line during monochrome mode printing by the printer of the second embodiment. FIG. 17 shows the first line to the 68th line, while FIG. 21 shows the 46th line to the 105th line. As in the second embodiment, if the amount of sub-scan feed performed in the unit scan operation is 2 dots or more, the main scan lines recorded by each unit scan operation are partially and alternately positioned. Become. For example, in the example of FIG. 21, the area indicated by the arrow L11 on the printing paper is recorded only by the first unit scan operation, and the area indicated by the arrow L12 is recorded only by the second unit scan operation. On the other hand, in the area indicated by the arrow L11m, the 62nd, 63rd, and 66th lines are recorded by the first unit scan operation, whereas the 61st, 64th, and 64th lines sandwiched between them are recorded. 65 lines are recorded in the next unit scan operation. That is, the main scan line recorded by the first unit scan operation and the main scan line recorded by the second unit scan operation are alternately present. For this reason, the boundary between the achromatic unit bands recorded in each unit scan operation is less noticeable, and the quality of the printing result is improved. The same applies to color mode printing shown in FIG. 16, as will be described later. The same applies to the boundary between the achromatic unit band and the color unit band.

  Other single chromatic color nozzle groups C, M, and Y and a specific black nozzle group K0 used in color mode printing can be considered in the same manner. That is, taking the yellow nozzle group of FIG. 16 as an example, the main scan lines recorded by the nozzles # 1 to # 5 of the yellow nozzle group in one unit scan operation are 20 lines from the first line to the 26th line. The main scanning lines that are recorded without gaps in the sub-scanning direction are 14 main scanning lines from the seventh line to the twentieth line. That is, the number of main scanning lines L2 of the single chromatic color unit band of the single chromatic color nozzle group Y, M, C is 14 lines. The specific black nozzle group K0 can be considered in the same manner as the cyan nozzle group C. The number of main scanning lines of the color unit band is 14 lines. On the other hand, the number of main scanning lines of the color unit line is 20 lines.

  Referring to FIG. 16, in the color mode sub-scan performed after the fourth pass, the yellow nozzle # 1 is sent from the position of the 10th line to the position of the 21st line. That is, the color mode sub-scan feed amount Sc is 11 dots. The sub-scan for color mode is a bundle of main scan lines for which recording has been completed in the immediately preceding unit scan operation, and is a main scan line at the lower end of a bundle of main scan lines arranged without gaps in the sub-scan direction (FIG. 16). The uppermost nozzle (nozzle # 1 of the yellow nozzle group) among the nozzles of the single chromatic nozzle group is located in the main scanning line (the 21st line) immediately below the 20th line). To be done. By performing such color mode sub-scanning, each main scanning line is recorded without gaps in color mode printing.

  If the nozzle pitch of the single chromatic color nozzle group C, M, Y used in color mode printing is k1 × D (k1 is an integer of 2 or more), the main scanning performed in the unit scan operation of color mode printing. The number of times is k1, and the number of sub-scans performed in the unit scan operation is (k1-1) times. Further, the sub-scan feed amount Suc performed in the unit scan operation can be expressed as follows.

  Suc = m2 × D (3)

  Here, m2 may be an integer that is 2 or more and prime with k1. However, it is preferable that it is the smallest number or the second smallest number among the integers that are prime and equal to or larger than two. In the color mode printing of the second embodiment, m2 is 3. This is the smallest number among integers that are prime and equal to or greater than two.

  Further, when the number of nozzles of the single chromatic nozzle group C, M, Y is N, the feed amount Sc for the color mode sub-scan is expressed by the following equation.

Sc = N × k1 × D-Suc × (k1-1)
= {N * k1-m2 * (k1-1)} * D (4)

  FIG. 22 and FIG. 23 are explanatory diagrams showing the recording of the main scanning line during color mode printing by the printer of the second embodiment. FIG. 22 shows 16 passes after the start of printing, whereas FIG. 23 shows 12 passes before the end of printing. As shown in FIG. 22, in the color mode printing of the second embodiment, the area from the upper end to the 46th line is a non-printable area. Also, as shown in FIG. 18, the area from the bottom to the 46th line from the bottom is also a non-printable area.

  24 and 25 are explanatory diagrams showing recording of the main scanning line according to the comparative example. FIG. 24 shows 14 passes after the start of printing, and FIG. 25 shows 14 passes before the end of printing. In the comparative example, interlaced printing that repeats sub scanning of 5 dots is performed in a printing apparatus having the same hardware configuration as that of the second embodiment. When interlaced printing is performed, as shown in FIGS. 24 and 25, the unprintable area is 52 lines on both the upper end side and the lower end side.

  In the color mode printing of the second embodiment, printing that repeats the unit scan operation is performed instead of interlaced printing. For this reason, as shown in FIGS. 22 and 24, and FIGS. 23 and 25, the non-printable area is smaller in the second embodiment than in the comparative example. Further, in the color mode printing of the second embodiment, the sub-scan feed amount m2 dots performed in the unit scan operation is the minimum number among integers which are prime and 2 or more as the nozzle pitch k3. It is a dot. Therefore, in the printing in which the unit scan operation with the feed amount Suc of 2 or more is performed, the unprintable area is the smallest.

  FIG. 26 is an explanatory diagram showing the recording of the main scanning line during color mode printing by the printer of the second embodiment. FIG. 22 shows the first line to the 73rd line, while FIG. 26 shows the 37th line to the 93rd line. As in the second embodiment, if the amount of sub-scan feed performed in the unit scan operation is 2 dots or more, the main scan lines recorded by each unit scan operation are partially and alternately positioned. Become. For example, in the example of FIG. 26, the area indicated by the arrow L21 on the printing paper is recorded with cyan dots only in the first unit scan operation (first pass to fourth pass), and the area indicated by the arrow L22 is 2 Only in the second unit scan operation (fifth pass to eighth pass), cyan dots are recorded. On the other hand, in the region indicated by the arrow L21m, the 62nd, 63rd, and 66th lines are printed with cyan and black dots in the first unit scan operation, but are sandwiched between them. In the 61st, 64th, and 65th lines, cyan and black dots are recorded in the next unit scan operation. That is, there are alternately main scanning lines in which cyan and black dots are recorded in the first unit scanning operation and main scanning lines in which cyan and black dots are recorded in the second unit scanning operation. For this reason, the boundary between the achromatic unit bands recorded in each unit scan operation is less noticeable, and the quality of the printing result is improved.

(2) Transition from color mode printing to monochrome mode printing:
FIG. 27 is an explanatory diagram showing how image data including a color area and a monochrome area is recorded in the second embodiment. Here, how the printing is performed according to the flowchart of FIG. 6 when the unit scan operation as shown in FIGS. 15 and 16 is performed will be described. In FIG. 27 and the subsequent figures, the numbers of the respective paths are described without being omitted, and therefore, for the sake of easy understanding, a separator is put in the path number column for each unit path. In the example of FIG. 27, the upper side from the 70th line of the image data is a color area, and the lower side from the 71st line is a monochrome area. Therefore, first, color mode printing is executed.

  Each nozzle does not initially reach the monochrome area. Although not shown in FIG. 27, some nozzles of the specific black nozzle group K0 reach the monochrome area from the fifth pass. At this time, the main scan lines in the monochrome area are recorded by the nozzles # 11 to # 15 of the specific black nozzle group K0. Similarly, in the 12th to 17th passes shown in FIG. 27, the main scan lines in the monochrome area are recorded by the nozzles # 11 to # 15 of the specific black nozzle group K0.

  In the state after the 16th pass, when the color mode sub-scanning is performed next, only the main scanning line of the monochrome area is included in the color unit band. That is, in the flowchart of FIG. 6, it is determined in step S24 that there is no color line. For this reason, after the 17th pass, the process proceeds to monochrome mode printing, monochrome mode sub-scan with a feed amount Sm = 51 dots is performed, and all nozzles of the black nozzle group are used in the 17th to 20th passes. Unit scan operation is performed.

  In the example of FIG. 27, it is possible to print a color image for the area up to the 80th line by printing up to the 16th pass for recording the color area. This range Ac is indicated by an arrow. The nozzle # 5 at the lower end of the black nozzle group K0 at the end of the 16th pass is at the position of the 126th line. This position is indicated by HPce in FIG. The difference between the position HPce of the lower end nozzle of the black nozzle group K0 when the color area has been printed and the lower end position of the area Ac where the color image can be printed is 46 dots. This 46-dot area is equal to the non-printable area on the lower end side in color mode printing (see FIG. 23).

  In the color mode printing of the second embodiment, printing that repeats the unit scan operation is performed instead of interlaced printing. Further, in the color mode printing of the third embodiment, the sub-scan feed amount m2 dots performed in the unit scan operation is the minimum number among the integers that are prime and two or more as the nozzle pitch k1. Therefore, the deviation between the relative position HPce of the print head with respect to the printing paper at the end of color mode printing and the end of the range Ac on which the color printing can be performed on the printing paper is small. As a result, when shifting from color mode printing to monochrome mode printing, it is unlikely that sub-scanning will be performed in the reverse direction to normal.

  As described above, in monochrome mode printing and color mode printing, the first, fourth, fifth, and seventh and subsequent lines are recorded at the front end of the area where each unit scan operation is recorded. Yes. Similarly, the first and fourth lines, the fifth line, and the lines before the seventh line are recorded from the rear end. That is, the arrangement of the lines where dots are recorded and the lines where no dots are recorded are the same at the front end and rear end of the area where the unit scan operation is recorded. Therefore, in the second embodiment, in the vicinity of the boundary between the monochrome area and the color area, the monochrome mode printing is changed to the color mode printing, and the color mode printing is changed to the monochrome mode printing. The image quality at the boundary between the area and the color area is unlikely to deteriorate.

  In addition, it is not restricted to an aspect like a 2nd Example that such an effect is acquired. That is, if the nozzle pitches of the achromatic color nozzle group and the chromatic color unit nozzle group are equal and the unit scan operations in the monochrome mode printing and the color mode printing are the same, the front end and the rear end of the area where the unit scan operation is recorded The arrangement of the lines where dots are recorded and the lines where no dots are recorded are the same. As a result, the image quality at the boundary between the monochrome area and the color area is unlikely to deteriorate.

(3) Transition from monochrome mode printing to color mode printing:
28 and 29 are explanatory views showing how image data including a color area and a monochrome area is recorded in the second embodiment. Here, how the printing is performed according to the flowchart of FIG. 12 when the unit scan operation as shown in FIGS. 15 and 16 is performed will be described. In FIG. 28 and FIG. 29, the fifth to eighth paths are described overlappingly. In the example of FIGS. 28 and 29, the upper side from the 82nd line of the image data is a monochrome area, and the lower side from the 83rd line is a color area. Therefore, at first, monochrome mode printing is executed.

  In the state after the fourth pass, when the monochrome mode sub-scan is performed next, as shown on the right side of FIG. 28, the lower end of the achromatic unit band is positioned in the color area. However, when the color mode sub-scan is performed next, the lower end of the achromatic unit band is located in the monochrome area as shown on the right side of FIG. That is, in this state, in the flowchart of FIG. 12, it is determined in step S44 that there is a color line, and in step S52, it is determined that there is no color line. For this reason, after the fourth pass, alignment feed of the feed amount Sm1 = 13 dots is performed (step S54), and in the fifth to eighth passes, a unit scan operation is performed using some of the nozzles of the black nozzle group. Is performed (step S56).

  As shown in FIG. 28, in the first to fourth passes, the seventh to 60th lines are continuously recorded in the sub-scanning direction. The area where recording is not completed is the area of the 61st to 82nd lines. The 61st to 82nd line areas include the 62nd, 63rd, and 66th lines in which dots have already been recorded. As shown in the right side of FIG. 28, the range of the achromatic color unit band in the case of the alignment feed is the 29th to 82nd lines, so the remaining monochrome area is obtained by the unit scan operation after the alignment feed. Can all be recorded.

  After the eighth pass, as shown in FIG. 29, the process shifts to color mode printing. That is, after the eighth pass, color mode sub-scan with a feed amount Sc = 11 dots is performed, and after the ninth pass, each single chromatic color nozzle group and a specific black nozzle group are used.

  In the example of FIG. 29, it is possible to print a monochrome image for the area up to the 82nd line by printing up to the eighth pass for recording the monochrome area. This range Am is indicated by an arrow. The nozzle at the lower end of the black nozzle group K0 at the end of the eighth pass is at the position of the 88th line. This position is indicated by HPme in FIG. The deviation between the position HPme of the lower end nozzle of the black nozzle group K0 when the monochrome area has been printed and the lower end position of the area Am where the monochrome image can be printed is 6 dots. This 6-dot area is equal to the non-printable area on the lower end side in monochrome mode printing (see FIG. 18).

  In the monochrome mode printing of the second embodiment, printing that repeats the unit scan operation is performed instead of interlaced printing. Further, in the monochrome mode printing of the second embodiment, the sub-scan feed amount m1 dots performed in the unit scan operation is the minimum number among the integers that are prime and two or more as the nozzle pitch k2. Therefore, the deviation between the relative position HPme of the print head with respect to the printing paper at the end of monochrome mode printing and the end of the range Am in which color printing on the printing paper is possible is small. As a result, when shifting from monochrome mode printing to color mode printing, there is a low possibility that sub-scanning will be performed in the reverse direction to normal.

  FIG. 30 is an explanatory diagram showing how image data including a color area and a monochrome area is recorded in the second embodiment. In the example of FIG. 30, the upper area from the 76th line of the image data is a monochrome area, and the lower area from the 77th line is a color area.

  In the state after the fourth pass, the lower end of the achromatic unit band is colored as shown on the right side of FIG. 30 regardless of whether the monochrome mode sub-scan or color mode sub-scan is performed next. Will be located in the region. That is, in this state, in the flowchart of FIG. 12, it is determined in step S44 that there is a color line, and in step S52, it is also determined that there is a color line. For this reason, after the fourth pass, the process proceeds to color mode printing as it is. That is, after the fourth pass, color mode sub-scan with a feed amount Sc = 11 dots is performed, and after the fifth pass, each single chromatic nozzle group C, M, Y and specific black nozzle group K0 (nozzle # 11 to # 15) are used.

  The unit bands recorded by the specific black nozzle group K0 in the fifth to eighth passes are the 67th to 80th lines. Therefore, the 61st to 76th lines (remaining monochrome areas) that have not been recorded until the fourth pass can be recorded by the specific black nozzle group K0 in the fifth to eighth passes.

  In the example of FIGS. 28, 29, and 30, whether or not to shift from monochrome mode printing to color mode printing is determined according to the flowchart of FIG. 12, but may be determined according to the flowchart of FIG. That is, the number of main scanning lines Lr1 in the remaining monochrome area is compared with the number of main scanning lines L1 in the achromatic unit band and the number of main scanning lines L2 in the single chromatic unit band, and whether or not to shift to color mode printing. Judgment may be made.

C. Third embodiment:
FIG. 31 is an explanatory diagram showing the arrangement of the nozzles of the printer of the third embodiment. The printer of the third embodiment is different from the printer of the first embodiment in the number and arrangement of nozzles on the print head. The printer of the third embodiment has the same hardware configuration as that of the printer of the first embodiment in other respects.

  In FIG. 31, the vertical dimension corresponding to one square corresponds to the main scanning line pitch D. In the third embodiment, as shown in FIG. 31, each of the single chromatic nozzle groups C, M, and Y includes eight nozzles. The nozzles of each nozzle group are arranged in the sub-scanning direction at a nozzle pitch that is four times the main scanning line pitch. The nozzles of each nozzle group are arranged so as to be aligned in the main scanning direction.

  The black nozzle group K is arranged in two rows. The nozzle rows are K0 and K1, respectively. Each nozzle row includes 8 nozzles. The nozzles of each nozzle row are arranged in the sub-scanning direction at a nozzle pitch that is four times the main scanning line pitch. The nozzles constituting one nozzle row K0 are arranged so as to be aligned with the nozzles of the single chromatic color nozzle groups C, M, and Y in the main scanning direction. The nozzles in the nozzle row K0 are used in both monochrome mode printing and color mode printing. This nozzle row is also called a specific black nozzle group K0.

  The nozzles of the other nozzle row K1 are used in monochrome mode printing and are not used in color mode printing. The nozzles of the nozzle row K1 are arranged so as to be shifted in the sub-scanning direction by twice the main scanning line pitch with respect to each nozzle of the specific black nozzle group K0. As a result, the pitch of the nozzles constituting the single chromatic nozzle group C, M, Y in the main scanning direction is 4 dots, whereas the pitch of the nozzles constituting the black nozzle group K is 2 dots. The nozzles constituting the black nozzle group K are twice as many as the nozzles constituting the single chromatic nozzle group C, M, Y.

(1) Color mode printing and monochrome mode printing:
FIG. 32 is an explanatory diagram showing the recording of the main scanning line during monochrome mode printing by the printer of the third embodiment. In FIG. 32 and below, one path is displayed as one column. For this reason, the nozzle row K0 and the nozzle row K1 are represented on the same row. In the monochrome mode printing of the third embodiment, in one unit scan operation, two main scans and one sub scan performed between them are performed. The sub-scan feed amount Sum performed during the main scan is three times the main scan line pitch, that is, 3 dots. Further, the feed amount Sm of the monochrome mode sub-scan performed during each unit scan operation is 29 times the main scan line pitch, that is, 29 dots. In the example of FIG. 32, for example, during the second pass and the third pass, the nozzle # 1 of the specific black nozzle group K0 is located on the 33rd line from the relative position where the nozzle # 1 is located on the fourth line on the printing paper. The sub-scan of 30 dots is performed up to the relative position at the position.

  If the nozzle pitch of the black nozzle group K used in monochrome mode printing is k2 × D (k2 is an integer of 2 or more), the number of main scans performed in the unit scan operation is k2, and in the unit scan operation The number of sub-scans performed is (k2-1) times. When the number of nozzles of each of the single chromatic nozzle groups C, M, and Y is N, the sub-scan feed amount Sum and the monochrome mode sub-scan feed amount Sm performed in the unit scan operation are expressed by the following equation (1). And Equation (2). However, in the third embodiment, p is 2 in the formula (2).

  Note that m1 that defines the feed amount of the sub-scan performed in the unit scan operation may be 2 or more and an integer that is prime to k. However, it is preferable that the nozzle pitch k2 is the smallest number or the second smallest number among integers that are prime and equal to or larger than two. In the monochrome mode printing of the third embodiment, m1 is 3. This is the smallest number among integers that are prime and 2 or more.

  As shown in FIG. Y01, in the monochrome mode printing of the third embodiment, the 32nd and 34th lines are recorded by the first unit scan operation (first pass and second pass), and the 33rd line The 35th line is recorded in the second unit scan operation (third pass and fourth pass). For this reason, the main scanning lines recorded in the first unit scan operation and the main scanning lines recorded in the second unit scan operation exist in the 32nd to 35th line areas. Become. Therefore, the boundary of the area recorded by each unit scan operation is not easily noticeable. The same applies to the areas recorded in each unit scan operation after the second unit scan operation. For this reason, the monochrome mode printing of the third embodiment has a high quality print result.

  In printing as shown in FIG. 32, the first line and the second line at the top of the area on the printing paper on which the nozzles are arranged at the start of printing are unprintable areas. Due to symmetry, the lowermost line and the second line from the bottom of the area on the printing paper on which the nozzles are arranged at the end of printing are also unprintable areas. In the monochrome mode printing of the third embodiment, not the interlaced printing but the printing that repeats the unit scan operation is performed, and therefore this non-printable area is small. Furthermore, in the monochrome mode printing of the third embodiment, the feed amount of the sub-scan performed in the unit scan operation is 3 dots, which is the minimum number of integers that are prime and 2 or more of the nozzle pitch k2. is there. Therefore, in the printing where the boundary of the area recorded by each unit scan operation is not conspicuous, the unprintable area is the smallest.

  FIG. 33 is an explanatory diagram showing the recording of the main scanning line during color mode printing by the printer of the third embodiment. Since the positions of each nozzle in the sub-scanning direction are the same in the nozzle groups C, M, Y, and K0, only the nozzle numbers are shown in FIG. In the color mode printing of the third embodiment, four main scans and three sub-scans performed therebetween are performed in one unit scan operation. The sub-scan feed amount Suc performed during the main scan is 3 dots. Further, the feed amount Sc of the color mode sub-scan performed during each unit scan operation is 23 dots. In the example of FIG. 32, for example, between the fourth pass and the fifth pass, the relative position where the nozzle # 1 is located at the position of the 33rd line from the relative position where the nozzle # 1 is located at the position of the 10th line on the printing paper. So far, 23-dot sub-scanning has been performed.

  If the nozzle pitch of the single chromatic color nozzle group C, M, Y used in the color mode printing is k1 × D (k1 is an integer of 2 or more), the number of main scans performed in the unit scan operation is also k1. The number of sub-scans performed in the unit scan operation is (k1-1) times. If the number of nozzles of each of the single chromatic nozzle groups C, M, and Y is N, the sub-scan feed amount Suc and the color-mode sub-scan feed amount Sc performed in the unit scan operation are: The equations (3) and (4) are also satisfied. In the color mode printing of the third embodiment, m2 that defines the feed amount of the sub-scan performed in the unit scan operation is 3. This is the smallest number among integers that are prime and equal to or larger than the nozzle pitch k1.

  In the color mode printing of the third embodiment, the 34th, 35th and 38th lines are recorded by the first unit scan operation (1st to 4th passes), and the 33rd and 36th lines. The 37th line is recorded by the second unit scan operation (fifth to eighth passes). For this reason, the area of the 33rd to 38th lines includes the main scanning line recorded by the first unit scanning operation and the main scanning line recorded by the second unit scanning operation. Become. As a result, in the monochrome mode printing of the third embodiment, the boundary of the area recorded by each unit scan operation is not noticeable, and the quality of the printing result is high.

  In printing as shown in FIG. 33, the first to sixth lines at the top of the area on the printing paper on which the nozzles are arranged at the start of printing are non-printable areas. Due to the symmetry, the area from the bottom line to the sixth line from the bottom line among the areas on the printing paper on which the nozzles are arranged at the end of printing is also a non-printable area. In the color mode printing of the third embodiment, not the interlaced printing but the printing that repeats the unit scan operation is performed, and thus this non-printable area is small. Further, in the color mode printing of the third embodiment, the feed amount of the sub-scan performed in the unit scan operation is 3 dots, which is the smallest number among integers that are prime and 2 or more. Therefore, in the printing where the boundary of the area recorded by each unit scan operation is not conspicuous, the unprintable area is the smallest.

(2) Transition from monochrome mode printing to color mode printing:
FIG. 34 is an explanatory diagram showing how image data including a color area and a monochrome area is recorded in the third embodiment. Hereinafter, printing in the third embodiment in the case where the first to 53rd lines and the 99th and subsequent lines are monochrome areas and the 54th to 98th lines are color areas will be described. In FIG. 34, only C is shown in the single chromatic nozzle group C, M, Y and the specific black nozzle group K0 used in the color mode printing for the sake of simplicity. In addition, nozzles that are not used are indicated with ().

  In monochrome mode printing, nozzle rows K0 and K1 are used. In the monochrome area, dots are recorded by main scanning in the first to fourth passes by these nozzles. By printing from the first pass to the fourth pass, it is possible to print a monochrome image for the region from the first to the 64th line. Let this range be Am1. The nozzle # 8 of the black nozzle group K1 at the end of the fourth pass is at the position of the 66th line. This position is indicated by HPme in FIG.

  The difference between the position HPme of the nozzle # 8 of the black nozzle group K1 at the time when the monochrome area has been printed and the lower end position of the area Am1 where the monochrome image can be printed is 2 dots. This 2-dot area is equal to the non-printable area on the lower end side in monochrome mode printing (see FIG. 32). In the monochrome mode printing of the third embodiment, printing that repeats the unit scan operation is performed instead of interlaced printing. Furthermore, in the monochrome mode printing of the third embodiment, the sub-scan feed amount m1 performed in the unit scan operation is the smallest number among integers that are prime and equal to or larger than 2. Therefore, this area is small.

  After the fourth pass is completed, alignment feed is performed. In the alignment feed, the main scanning line at the upper end of the single chromatic color unit band recorded by printing performed using the single chromatic color nozzle group C, M, Y and the specific black nozzle group K0 is the 54th scanning line. It is done to the position where it becomes a line. The feed amount of the alignment feed is represented by Sm1. Thereafter, dots are recorded in the color area using the single chromatic nozzle group C, M, Y and the specific black nozzle group K0. The nozzles in the nozzle row K1 that are not used are indicated with () in FIG. By printing after the alignment feed, a color image can be printed for the area below the 54th line. Let this range be Ac. The nozzle # 1 of the specific black nozzle group K0 at the time when the alignment feed is finished is at the position of the 48th line. This position is indicated by HPcs in FIG.

  The difference between the position HPcs of the nozzle # 1 of the specific black nozzle group K0 at the start of printing the color area and the upper end position of the area Ac where the color image can be printed is 6 dots. This 6-dot area is equal to the non-printable area on the upper end side in color mode printing (see FIG. 33). In the third embodiment, printing that repeats the unit scan operation is performed instead of interlaced printing. Furthermore, in the color mode printing of the third embodiment, the sub-scan feed amount m2 performed in the unit scan operation is the minimum number among integers that are prime and equal to or greater than two. Therefore, this area is small.

  In the third embodiment, the deviation between the relative position HPme of the print head with respect to the printing paper at the end of monochrome mode printing and the end of the range Am1 where monochrome printing on the printing paper is possible is small. Therefore, in monochrome mode printing, it is not necessary to perform sub-scanning to a relative position where the print head greatly exceeds the boundary between the monochrome area and the color area. Further, as described above, the deviation between the relative position HPcs of the print head with respect to the printing paper at the start of color mode printing and the end of the range Ac on which the color printing can be performed on the printing paper is small. Therefore, in color mode printing, there is no need to start printing from a relative position that greatly exceeds the boundary between the monochrome area and the color area. As a result, in the third embodiment, when shifting from monochrome mode printing to color mode printing, it is unlikely that sub-scanning will be performed in the reverse direction.

  FIG. 35 is an explanatory diagram showing how image data including a color area and a monochrome area is recorded in the third embodiment. In the color area, dots are recorded by the main scanning from the fifth pass to the twelfth pass. By printing from the fifth pass to the twelfth pass, it is possible to print a monochrome image for the region from the 54th to the 111th line. This range Ac is indicated by an arrow (see FIGS. 34 and 35). The nozzle # 8 of the black nozzle group K1 at the end of the 12th pass is at the position of the 119th line. This position is indicated by HPce in FIG.

  The difference between the position HPce of the nozzle # 8 of the black nozzle group K1 at the time when the printing of the color area is finished and the lower end position of the area Ac where the color image can be printed is 6 dots. This 6-dot area is equal to the non-printable area on the lower end side in color mode printing (see FIG. 32). In the color mode printing of the third embodiment, printing that repeats the unit scan operation is performed instead of interlace printing. Furthermore, in the color mode printing of the third embodiment, the sub-scan feed amount m2 performed in the unit scan operation is the minimum number among integers that are prime and equal to or greater than two. Therefore, this area is small.

  After the twelfth pass is completed, alignment feed is performed. The alignment feed is then performed until the main scanning line at the upper end of the achromatic unit band recorded by printing performed using the black nozzle group K reaches the 99th line. A feed amount of the positioning feed is Sc1. Thereafter, using the black nozzle group K (nozzle rows K0, K1), dots are recorded in the monochrome area. By printing after alignment feeding, it is possible to print a monochrome image for the area below the 99th line. This range is Am2. The nozzle # 1 of the specific black nozzle group K0 at the time when the alignment feed is finished is at the position of the 97th line. This position is indicated by HPms in FIG.

  In FIG. 35, the deviation between the position HPms of the nozzle # 1 of the specific black nozzle group K0 when printing of the monochrome area starts and the upper end position of the area Am2 where the monochrome image can be printed is 2 dots. This 2-dot area is equal to the non-printable area on the upper end side in monochrome mode printing (see FIG. 33). In the third embodiment, printing that repeats the unit scan operation is performed instead of interlaced printing. Furthermore, in the monochrome mode printing of the third embodiment, the sub-scan feed amount m1 performed in the unit scan operation is the smallest number among integers that are prime and equal to or larger than 2. Therefore, this area is small.

  In the third embodiment, the deviation between the relative position HPce of the print head with respect to the print paper at the end of color mode printing and the end of the range Ac on the print paper where color printing is possible is small. Therefore, in color mode printing, it is not necessary to perform sub-scanning to a relative position where the print head greatly exceeds the boundary between the monochrome area and the color area. Further, as described above, the deviation between the relative position HPms of the print head with respect to the printing paper at the start of monochrome mode printing and the end of the range Am2 where monochrome printing on the printing paper is possible is small. Therefore, in monochrome mode printing, there is no need to start printing from a relative position that greatly exceeds the boundary between the monochrome area and the color area. As a result, in the third embodiment, when shifting from color mode printing to monochrome mode printing, there is a low possibility of performing sub-scanning in the reverse direction.

D. 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.

  36 and 37 are explanatory diagrams showing other unit scan operations. The color mode printing and monochrome mode printing described above can be applied to nozzle configurations and unit scan operations other than the nozzle configurations and unit scan operations shown in FIGS. 4, 5, 15, and 16. . For example, as shown in FIG. 36 and FIG. 37, in the nozzle configuration similar to the nozzle configuration shown in FIG. 15 and FIG. The present invention can also be applied to the case where the unit scan operation is completed. In such an embodiment, as shown in FIG. 36, the achromatic unit band recorded in one unit scan operation is 60 continuous main scanning lines, and the single chromatic unit band is shown in FIG. As shown, there are 20 consecutive main scan lines. In such an embodiment, all the main scan lines recorded by the unit scan operation are arranged without a gap in the direction of the side runner, so that printing can be executed by the same process as in the first embodiment. .

  Further, the nozzle pitch k is not limited to 4, and may be an appropriate value such as 6, 8. In that case, it is preferable that the feed amount of the minute feed performed in the unit scan operation is a prime value with respect to the nozzle pitch k. By doing so, it is possible to perform sub-scanning with a constant feed amount and record each main scanning line without any gap. Further, the number of micro feeds is preferably (k-1).

  38 and 39 are explanatory views showing the arrangement of nozzles in the print heads 28a and 28b according to another embodiment. In the above embodiment, the nozzles included in each nozzle group are arranged in one row, but the nozzles included in each nozzle group may be arranged in two rows as shown in FIG. There may be three or more rows. Further, the nozzles of the nozzle group may be arranged in a so-called “staggered” arrangement that is alternately arranged in the sub-scanning direction SS. In the above embodiment, the cyan, magenta, and yellow nozzle rows are arranged in a row in the sub-scanning direction SS, but the single chromatic color nozzle group has a main scanning direction MS as shown in FIG. May be provided at different positions. In addition, the range in which the achromatic nozzle group exists in the sub-scanning direction SS may not coincide with the range in which a plurality of single chromatic color nozzle groups exist in the sub-scanning direction SS. Further, in the above embodiment, the single chromatic color nozzle group is each of the cyan, magenta, and yellow nozzle groups. However, the single chromatic color nozzle group is, for example, as shown in FIG. A nozzle group that ejects ink of other colors such as magenta and dark yellow may also be included. Further, a nozzle that discharges achromatic ink such as gray may be included. That is, as long as the “single chromatic color nozzle group” has an equal number of nozzles and ejects different inks, the arrangement of the nozzles, the ink color, and the number of ink colors are not limited. The ink ejected by the single chromatic nozzle group is ink used in color mode printing.

  In the above embodiment, the achromatic nozzle group is a nozzle group that ejects black ink. However, if the print data includes an area to be recorded with a single color ink other than black, the area is designated as the achromatic color nozzle group. It is also possible to eject ink for recording from the achromatic nozzle group. Furthermore, two or more achromatic nozzle groups may be provided. In that case, the number of nozzles of each achromatic nozzle group is preferably equal.

  In the above embodiment, the specific black nozzle group K0 used in the color mode printing is a group of nozzles located at the lowest position among the nozzles of the black nozzle group K. However, as shown in FIG. 38, the specific achromatic nozzle group may be a nozzle group K0 located near the center in the sub-scanning direction SS of the achromatic nozzle group, or a nozzle located at another position. Also good. That is, any nozzle group that is a part of the achromatic nozzle group and includes the same number of nozzles as the single chromatic nozzle group may be used.

  That is, the print head has a plurality of nozzles arranged at a nozzle pitch k × D that is k times the main scanning line pitch D (k is an integer of 2 or more), and each ejects different chromatic inks. A print head having a single chromatic nozzle group and an achromatic nozzle group that has a larger number of nozzles and ejects achromatic ink than the single chromatic nozzle group arranged at a nozzle pitch k × D. Good.

  Color mode printing uses a specific achromatic nozzle group that is part of the achromatic nozzle group and includes the same number of nozzles as the single chromatic nozzle group and a plurality of single chromatic nozzle groups in the main scan. Then, a unit scan operation including at least dots formed on the main scan line of the color area and composed of k times of main scan and (k−1) times of sub-scanning with a predetermined first feed amount, Any printing may be used as long as color mode sub-scanning with a predetermined second feed amount is repeated between unit scanning operations.

  In monochrome mode printing, all the nozzles of the achromatic nozzle group are used in the main scan without using the nozzles of the single chromatic nozzle group, and dots are formed on the main scan line of the monochrome area. Any printing that performs monochrome mode printing in which unit scan operations are repeated while performing monochrome mode sub-scanning with a fourth feed amount that is larger than the second feed amount may be used.

  In each of the above embodiments, an ink jet printer has been described. However, the present invention is not limited to an ink jet printer, and is generally applicable to various printing apparatuses that perform printing using a print head. Further, the present invention is not limited to a method and apparatus for ejecting ink droplets, but can also be applied to a method and apparatus for recording dots by other means.

  In each of the above embodiments, a part of the configuration realized by hardware may be replaced with software, and conversely, a part of the configuration realized by software may be replaced by hardware. . For example, a part of the function of the head drive circuit 52 shown in FIG. 2 can be realized by software.

1 is a schematic configuration diagram of a printing system including a printer 20 according to a first embodiment. FIG. 3 is a block diagram illustrating a configuration of a control circuit 40 in the printer 20. FIG. 3 is an explanatory diagram showing the arrangement of nozzles provided in the print head. Explanatory drawing which shows the recording of the main scanning line by the unit scan operation | movement at the time of monochrome mode printing. Explanatory drawing which shows the recording of the main scanning line by the unit scan operation | movement at the time of color mode printing. 6 is a flowchart illustrating processing in color mode printing. Explanatory drawing which shows how image data containing a color area | region and a monochrome area | region is recorded. FIG. 6 is a block diagram showing another aspect of the control circuit of the printer 20. 6 is a flowchart illustrating processing in color mode printing. 6 is a flowchart illustrating processing in color mode printing. Explanatory drawing which shows how image data containing a color area | region and a monochrome area | region is recorded. 6 is a flowchart showing processing in monochrome mode printing. FIG. 10 is an explanatory diagram of another example showing how image data including a color area and a monochrome area is recorded. 10 is a flowchart illustrating an example of another process for monochrome mode printing. Explanatory drawing which shows the arrangement | positioning of the nozzle of the printer of 2nd Example, and recording of the main scanning line by unit scan operation | movement. Explanatory drawing which shows the arrangement | positioning of the nozzle of the printer of 2nd Example, and recording of the main scanning line by unit scan operation | movement. Explanatory drawing which shows the recording of the main scanning line at the time of monochrome mode printing by the printer of 2nd Example. Explanatory drawing which shows the recording of the main scanning line at the time of monochrome mode printing by the printer of 2nd Example. FIG. 5 is an explanatory diagram showing recording of main scanning lines according to a comparative example. FIG. 5 is an explanatory diagram showing recording of main scanning lines according to a comparative example. Explanatory drawing which shows the recording of the main scanning line at the time of monochrome mode printing by the printer of 2nd Example. Explanatory drawing which shows the recording of the main scanning line at the time of color mode printing by the printer of 2nd Example. Explanatory drawing which shows the recording of the main scanning line at the time of color mode printing by the printer of 2nd Example. FIG. 5 is an explanatory diagram showing recording of main scanning lines according to a comparative example. FIG. 5 is an explanatory diagram showing recording of main scanning lines according to a comparative example. Explanatory drawing which shows the recording of the main scanning line at the time of color mode printing by the printer of 2nd Example. Explanatory drawing which shows how the image data containing a color area | region and a monochrome area | region are recorded in 2nd Example. Explanatory drawing which shows how the image data containing a color area | region and a monochrome area | region are recorded in 2nd Example. Explanatory drawing which shows how the image data containing a color area | region and a monochrome area | region are recorded in 2nd Example. Explanatory drawing which shows how the image data containing a color area | region and a monochrome area | region are recorded in 2nd Example. Explanatory drawing which shows arrangement | positioning of the nozzle of the printer of 3rd Example. Explanatory drawing which shows the recording of the main scanning line at the time of monochrome mode printing by the printer of 3rd Example. Explanatory drawing which shows the recording of the main scanning line at the time of color mode printing by the printer of 3rd Example. Explanatory drawing which shows how the image data containing a color area | region and a monochrome area | region are recorded in 3rd Example. Explanatory drawing which shows how the image data containing a color area | region and a monochrome area | region are recorded in 3rd Example. Explanatory drawing which shows the nozzle of another structure, and unit scan operation | movement. Explanatory drawing which shows the nozzle of another structure, and unit scan operation | movement. Explanatory drawing which shows arrangement | positioning of the nozzle in the print head 28a of another aspect. Explanatory drawing which shows arrangement | positioning of the nozzle in the print head 28b of another aspect.

Explanation of symbols

DESCRIPTION OF SYMBOLS 20 ... Inkjet printer 22 ... Paper feed motor 24 ... Carriage motor 26 ... Platen 28, 28a, 28b ... Print head 30 ... Carriage 32 ... Operation panel 34 ... Sliding shaft 36 ... Drive belt 38 ... Pulley 39 ... Position sensor 40, 40s ... Control circuit 41 ... CPU
41a ... Color mode part 41a1 ... Transition part 41a2 ... First transition part 41a3 ... Second transition part 41b ... Monochrome mode part 41b0 ... Transition part 41b1 ... First transition part 41b2 ... Second transition part 42 ... PROM
43 ... Programmable ROM
44 ... RAM
DESCRIPTION OF SYMBOLS 50 ... Dedicated circuit for I / F 52 ... Head drive circuit 54 ... Motor drive circuit 56 ... Connector 60 ... Print head unit 88 ... Computer 90, 90a, 90b ... Actuator circuit 91-96 ... Actuator chip Ac ... Range in which color printing is possible Am, Am1, Am2: Range in which monochrome printing is possible D: Main scanning line pitch C: Cyan nozzle group HPce: Relative position of the print head at the end of color mode printing HPcs: Relative position of the print head at the start of color mode printing HPme ... Relative position of print head at the end of monochrome mode printing HPms ... Relative position of print head at the start of monochrome mode printing K ... Black nozzle group K0 ... Specific black nozzle group K1 ... Nozzle of black nozzle group K and specific black Nozzle group K1 nozzle L1 ... Number of main scanning lines in achromatic unit band L2: Number of main scanning lines in single chromatic unit band L11: Range of main scanning lines recorded by only the first unit scanning operation L11m: In first and second unit scanning operations Range of main scan line to be recorded L12 ... Range of main scan line to be recorded only by the second unit scan operation L21 ... Range of main scan line to be recorded only by the first unit scan operation L21m ... First and second time Main scan line range recorded by unit scan operation L22 ... Main scan line range recorded only by second unit scan operation Lr1 ... Number of main scan lines in the remaining monochrome area M ... Magenta nozzle group MS ... Main scan direction Arrow P representing printing paper PE PE element PS ... Print signal SS ... Arrow representing sub-scanning direction Sc ... Sub-scan for color mode Alignment feed amount Sc1... Alignment feed amount Sm... Monochrome mode subscan feed amount Sm1... Alignment feed amount Suc... Subscan feed amount in unit scan operation in color mode printing Sum. Sub-scan feed amount in unit scan operation Y ... Yellow nozzle group k ... Nozzle pitch n ... Nozzle

Claims (7)

A plurality of single chromatic color nozzle groups each having an equal number of nozzles arranged at a nozzle pitch k × D which is k times the main scanning line pitch D ( k is an integer of 2 or more) and respectively ejecting different chromatic color inks When using a printing apparatus having a print head and a achromatic nozzle group for ejecting achromatic ink comprises a number of nozzles than are arranged at nozzle pitch k × D wherein the single chromatic nozzle groups, While performing main scanning, ink droplets are landed on the printing medium to form dots, and during the main scanning, sub scanning is performed in a direction crossing the main scanning direction, so that the achromatic color on the printing medium A method for performing printing on a monochrome area recorded only with ink and a color area recorded using the chromatic ink,
(A) In the main scanning, a specific achromatic nozzle group that is a part of the achromatic nozzle group and includes the same number of nozzles as the single chromatic nozzle group and the plurality of single chromatic nozzle groups are used. to form a dot in at least the main scanning line on the color area, k main scans and a predetermined first feeding amount by the (k -1) times the color mode unit composed of a sub-scanning Performing color mode printing in which the scanning operation is repeatedly performed while performing color mode sub-scanning with a predetermined second feed amount between each color mode unit scanning operation;
(B) In the main scanning, using all the nozzles of the achromatic nozzle group without using the nozzles of the single chromatic nozzle group, forming dots on the main scanning line of the monochrome area; A unit scan operation for monochrome mode composed of k main scans and ( k −1) sub-scans with a third feed amount equal to the first feed amount is performed more than the second feed amount. Performing monochrome mode printing, repeatedly performing monochrome mode sub-scanning with a large fourth feed amount between unit scan operations for each monochrome mode, and
The step (a)
(A1) comprising a step of shifting to the monochrome mode printing when a predetermined condition is satisfied ,
The step (a1)
(A11) When it is assumed that the color mode sub-scanning is to be performed next, the main scanning line in which the plurality of single chromatic color nozzle groups can newly complete recording in one color mode unit scan operation. When all the main scanning lines of the color unit band, which are bundles and are arranged in the sub scanning direction without gaps, are located in the monochrome area, the printing includes the step of shifting to the monochrome mode printing. Method. The printing method according to claim 1, comprising:
The plurality of single chromatic color nozzle groups each include N (N is an integer of 2 or more) nozzles (C is 2 or more) arranged at the nozzle pitch k × D in the sub-scanning direction. Integer) nozzle row,
The achromatic nozzle group is a nozzle row composed of N × C nozzles arranged at the nozzle pitch k × D in the sub-scanning direction,
The first feed amount and the third feed amount are D,
The second feed amount is N × k × D,
The printing method, wherein the fourth feed amount is N × C × k × D. The printing method according to claim 1, comprising:
The plurality of single chromatic color nozzle groups each include N (N is an integer of 2 or more) nozzles (C is 2 or more) arranged at the nozzle pitch k × D in the sub-scanning direction. Integer) nozzle row,
The achromatic nozzle group is a nozzle row composed of N × C nozzles arranged at the nozzle pitch k × D in the sub-scanning direction,
The first feed amount and the third feed amount are m × D (m is an integer between 2 and k and a prime number),
The second feed amount is a bundle of main scanning lines for which recording has been completed in the immediately preceding unit scan operation for color mode, and a lower end of a bundle of main scanning lines arranged without gaps in the sub-scanning direction. A feed amount for performing the sub-scanning at a relative position such that the uppermost nozzle among the nozzles of the plurality of single chromatic color nozzle groups is located on the main scanning line immediately below the main scanning line. Yes,
The fourth feed amount is a bundle of main scanning lines recorded in the unit scan operation for monochrome mode immediately before, and a main scanning line at the lower end of a bundle of main scanning lines arranged without gaps in the sub-scanning direction. A printing method that is a feed amount for performing the sub-scanning at a relative position such that the uppermost nozzle of the achromatic nozzle group is positioned on the main scanning line immediately below the scanning line. By ejecting ink droplets from nozzles and landing on printing media to form dots, print data including monochrome areas recorded with only achromatic ink and color areas recorded with chromatic ink are printed. A printing device that performs printing,
A plurality of single chromatic color nozzle groups each having an equal number of nozzles arranged at a nozzle pitch k × D which is k times the main scanning line pitch D ( k is an integer of 2 or more) and respectively ejecting different chromatic color inks When a print head and a achromatic nozzle group for ejecting achromatic ink comprises a number of nozzles than are arranged at nozzle pitch k × D wherein the single chromatic nozzle groups,
A main scanning drive unit that performs main scanning for moving at least one of the print head and the print medium;
A sub-scanning drive unit that performs sub-scanning for moving at least one of the print head and the print medium in a direction crossing the main scanning direction;
A control unit for controlling each unit,
The controller is
In the main scanning, using a specific achromatic nozzle group that is a part of the achromatic nozzle group and includes the same number of nozzles as the single chromatic nozzle group, and the plurality of single chromatic nozzle groups, forming at least the main scanning line on the dot of the color area, the k times by the main scanning and a predetermined first feeding amount (k -1) sub-scan color mode unit scan operation consisting of A color mode unit that performs color mode printing that is repeatedly performed while performing color mode sub-scanning by a predetermined second feed amount between each color mode unit scan operation;
In the main scanning, dots are formed on the main scanning line of the monochrome region using all the nozzles of the achromatic nozzle group without using the nozzles of the single chromatic nozzle group, and k times A unit scan operation for monochrome mode composed of main scanning and ( k −1) sub-scans with a third feed amount equal to the first feed amount is larger than the second feed amount. A monochrome mode unit that performs monochrome mode printing, and repeatedly performs monochrome mode sub-scanning with each monochrome mode unit scan operation.
The color mode part is
A transition unit that transitions to the monochrome mode printing when a predetermined condition is satisfied ;
The transition unit is
Next, when it is assumed that the color mode sub-scanning is performed, the plurality of single chromatic color nozzle groups can newly complete recording in one unit scan operation, and a bundle of main scanning lines, A printing apparatus that shifts to the monochrome mode printing when all the main scanning lines of the color unit band, which are main scanning lines arranged without gaps in the sub-scanning direction, are located in the monochrome area. The printing apparatus according to claim 4, wherein
The plurality of single chromatic color nozzle groups each include N (N is an integer of 2 or more) nozzles (C is 2 or more) arranged at the nozzle pitch k × D in the sub-scanning direction. Integer) nozzle row,
The achromatic nozzle group is a nozzle row composed of N × C nozzles arranged at the nozzle pitch k × D in the sub-scanning direction,
The first feed amount and the third feed amount are D,
The second feed amount is N × k × D,
The printing apparatus in which the fourth feed amount is N × C × k × D. The printing apparatus according to claim 4, wherein
The plurality of single chromatic color nozzle groups each include N (N is an integer of 2 or more) nozzles (C is 2 or more) arranged at the nozzle pitch k × D in the sub-scanning direction. Integer) nozzle row,
The achromatic nozzle group is a nozzle row composed of N × C nozzles arranged at the nozzle pitch k × D in the sub-scanning direction,
The first feed amount and the third feed amount are m × D (m is an integer between 2 and k and a prime number),
The second feed amount is a bundle of main scanning lines for which recording has been completed in the immediately preceding unit scan operation for color mode, and a lower end of a bundle of main scanning lines arranged without gaps in the sub-scanning direction. A feed amount for performing the sub-scanning at a relative position such that the uppermost nozzle among the nozzles of the plurality of single chromatic color nozzle groups is located on the main scanning line immediately below the main scanning line. Yes,
The fourth feed amount is a bundle of main scanning lines recorded in the unit scan operation for monochrome mode immediately before, and a main scanning line at the lower end of a bundle of main scanning lines arranged without gaps in the sub-scanning direction. A printing apparatus having a feed amount for performing the sub-scanning at a relative position such that the uppermost nozzle of the achromatic nozzle group is positioned on a main scanning line immediately below the scanning line. A plurality of single chromatic color nozzle groups each having an equal number of nozzles arranged at a nozzle pitch k × D which is k times the main scanning line pitch D ( k is an integer of 2 or more) and respectively ejecting different chromatic color inks If, computer with a printing apparatus having a print head and a achromatic nozzle group for ejecting achromatic ink comprises a number of nozzles than are arranged at nozzle pitch k × D wherein the single chromatic nozzle groups In addition, while moving the print head relative to the printing medium to perform main scanning, ink droplets are landed on the printing medium to form dots, and the main scanning is performed between the main scanning. A sub-scan is performed in a direction crossing the direction, and printing is performed on a monochrome area recorded with only the achromatic color ink and a color area recorded with the chromatic color ink on the print medium. A computer-readable recording medium recording a computer program,
In the main scanning, using a specific achromatic nozzle group that is a part of the achromatic nozzle group and includes the same number of nozzles as the single chromatic nozzle group, and the plurality of single chromatic nozzle groups, forming at least the main scanning line on the dot of the color area, the k times by the main scanning and a predetermined first feeding amount (k -1) sub-scan color mode unit scan operation consisting of A color mode program for causing the computer to execute a process of performing color mode printing while repeatedly performing color mode sub-scanning with a predetermined second feed amount between each color mode unit scan operation;
In the main scanning, dots are formed on the main scanning line of the monochrome region using all the nozzles of the achromatic nozzle group without using the nozzles of the single chromatic nozzle group, and k times A unit scan operation for monochrome mode composed of main scanning and ( k −1) sub-scans with a third feed amount equal to the first feed amount is larger than the second feed amount. A monochrome mode program for causing the computer to execute monochrome mode printing, in which monochrome mode sub-scanning is repeatedly performed between each monochrome mode unit scanning operation, and the monochrome mode printing is performed.
The color mode program is
See containing a migration program proceeds to the monochromatic mode printing when a predetermined condition is satisfied,
The nozzle pitch of the single chromatic nozzle group and the nozzle pitch of the achromatic nozzle group are both k × D (k is an integer of 2 or more),
The first feed amount and the third feed amount are equal,
The migration program is
Next, when it is assumed that the color mode sub-scan is performed, the plurality of single chromatic color nozzle groups are bundles of main scan lines that can be newly completed in one color mode unit scan operation. When the main scanning lines of the color unit band, which are the main scanning lines arranged without gaps in the sub-scanning direction, are all located in the monochrome area, the process of shifting to the monochrome mode printing is executed on the computer. Let the recording medium.

Images