JP2018144342A - Printer and printing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique capable of improving printing quality.SOLUTION: A printer comprises: a recording head having a nozzle array in which a plurality of nozzles arranged side-by-side in a direction different from a main scanning direction; a main scanning section repeating main scanning for moving the recording head in the main scanning direction with respect to a printed matter; a sub-scanning section relatively moving the recording head and the printed matter in a sub-scanning direction different from the main scanning direction; and a control section repeating the main scanning such that a change period when a nozzle use range decreases or increases in association with movement of the recording head in the middle of the main scanning is included with a range where the nozzles are used out of the nozzle array as the nozzle use range, and performing printing.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a printing technique for performing main scanning and sub-scanning using a recording head.

  An ink jet recording apparatus described in Patent Document 1 includes a head unit including a liquid ejecting head including a nozzle row in which a plurality of nozzle openings are arranged in parallel, and a carriage mounted with the head unit and scanned along a carriage axis. And a tunnel-shaped cover member provided so as to surround the carriage scanned along the carriage axis and the head unit mounted on the carriage.

JP, 2006-196172, A

When ink droplets are ejected from the nozzle openings, in addition to the main droplets that land on the substrate to form the desired print, small satellite droplets separated from the main droplets are generated, and the nozzle plate and substrate May float during Accompanying the main scanning operation, the satellite droplets are rolled up and irregularly deposited on the substrate to be printed, so that printing smear called “wind pattern” may occur, resulting in a decrease in print quality.
The formation of the above-described wind pattern is particularly likely to occur in a band printing method in which the nozzle pitch for the purpose of high-speed printing is equal to the dot interval and a plurality of continuous raster lines are performed in one pass.

Note that the above-described problems can exist in various apparatuses.
One of the objects of the present invention is to provide a technique capable of improving print quality.

In order to achieve one of the above objects, the printing apparatus of the present invention includes a recording head having a nozzle row in which a plurality of nozzles are arranged in a direction different from the main scanning direction;
A main scanning section that repeats main scanning for moving the recording head in the main scanning direction with respect to the substrate;
A sub-scanning unit that relatively moves the recording head and the printing material in a sub-scanning direction different from the main scanning direction;
The range in which the nozzles are used in the nozzle row is set as the nozzle use range, and the main scan is repeated so that a change period in which the nozzle use range decreases or increases as the recording head moves is included during the main scan. And a control unit that performs printing.

Further, the present invention repeats main scanning in which a recording head having a nozzle row in which a plurality of nozzles are arranged in a direction different from the main scanning direction moves in the main scanning direction with respect to the printing material. A printing method for performing sub-scanning in which the recording head and the printing material are relatively moved in different sub-scanning directions,
The range in which the nozzles are used in the nozzle row is set as the nozzle use range, and the main scan is repeated so that a change period in which the nozzle use range decreases or increases as the recording head moves is included during the main scan. And printing.

  The aspect mentioned above can provide the technique which can improve printing quality.

FIG. 3 is a diagram schematically illustrating a configuration example of a printing apparatus. FIG. 5 is a diagram schematically illustrating an operation example of a printing apparatus in forward main scanning when paper is always fed. FIG. 6 is a diagram schematically illustrating an operation example of a printing apparatus in backward main scanning when paper is always fed. The figure which shows the example of the printing area | region for every pass typically. FIG. 10 is a diagram schematically illustrating another operation example of the printing apparatus in forward main scanning when paper is always fed. The figure which shows typically the example which matches each pixel of halftone data with a dot formation scheduled position. FIG. 10 is a diagram schematically illustrating another operation example of the printing apparatus in forward main scanning when paper is always fed. FIG. 9 is a diagram schematically illustrating another operation example of the printing apparatus in backward main scanning when paper is always fed. The figure which shows the example of the printing area | region for every pass typically. FIG. 6 is a diagram schematically illustrating an operation example of a printing apparatus when paper is intermittently fed. FIG. 10 is a diagram schematically illustrating another operation example of the printing apparatus when paper is intermittently fed. The figure which shows the example of the printing area | region for every pass typically. The flowchart which shows the example of the process which selects a setting. The flowchart which shows another example of the process which selects a setting. The figure which shows typically the example of the printing area | region for every path | pass in the case where a non-change period is included in the repeated main scanning. The figure which shows the comparative example of the printing method typically.

  Embodiments of the present invention will be described below. Of course, the following embodiments are merely examples of the present invention, and all the features shown in the embodiments are not necessarily essential to the means for solving the invention.

(1) Summary of technology included in the present invention:
First, the outline | summary of the technique included in this invention is demonstrated with reference to the example shown by FIGS. In addition, the figure of this application is a figure which shows an example typically, The expansion ratio of each direction shown by these figures may differ, and each figure may not match. Of course, each element of the present technology is not limited to the specific example indicated by the reference numeral.

[Comparative example]
FIG. 16 schematically shows an example of band printing as a comparative example of the printing method. FIG. 16 shows an example in which the position of the recording head 61 relative to the printing medium ME1 is shown in each pass P1 to P4, and rectangular print areas R1 to R4 are formed in each pass P1 to P4. Here, passes P1 and P3 are forward main scans, and passes P2 and P4 are backward main scans. The recording head 61 has a nozzle row 68 in which a plurality of nozzles 64 are arranged in an arrangement direction D1 orthogonal to the main scanning direction D2, and reciprocates in the main scanning direction D2 by main scanning means (not shown). The substrate ME1 is intermittently moved in the sub-scanning direction D3 (upward in FIG. 16) by a paper feeding unit (not shown). In the band printing shown in FIG. 16, the substrate ME1 is intermittently conveyed in the paper feed direction D31, and the recording head 61 is reciprocated in the forward direction D21 and the backward direction D22 while the conveyance of the substrate ME1 is stopped. ing. Each print region R1 to R4 of the print image IM1 is called a band, and all dots are formed in one pass P1 to P4.

  As shown in FIG. 16, the range in which the nozzle 64 is used in the nozzle row 68 in each main scan does not change regardless of whether the recording head 61 moves in the forward direction D21 or the backward direction D22. Here, when the ejection density of the ink droplets ejected from the recording head 61 increases, the ink droplets are slightly swept away by the air flow generated in the vicinity of the recording head 61, and a “wind ripple” phenomenon may occur. Such a “wind pattern” phenomenon is particularly likely to occur before or after the end of the main scanning of the recording head 61 or immediately before the start.

[Aspect 1]
As illustrated in FIG. 1 and the like, the printing apparatus 1 according to an aspect of the present technology includes a recording head 61, a main scanning unit 55, a sub-scanning unit (for example, a paper feed mechanism 53), and a control unit U1. As illustrated in FIGS. 2 and 3, the recording head 61 includes a nozzle row 68 in which a plurality of nozzles 64 are arranged in a direction (for example, the arrangement direction D1) different from the main scanning direction D2. The main scanning unit 55 repeats main scanning for moving the recording head 61 in the main scanning direction D2 with respect to the substrate ME1. The sub-scanning unit (53) relatively moves the recording head 61 and the substrate ME1 in a sub-scanning direction D3 different from the main scanning direction D2. Here, a range in which the nozzles 64 are used in the nozzle row 68 is defined as a nozzle usage range RN. As illustrated in FIG. 4 and the like, the control unit U1 includes the main scanning so that a change period T0 in which the nozzle use range RN decreases or increases as the recording head 61 moves during the main scanning. Repeat to print.

  In the first aspect, the main scan is repeated so that the nozzle use range RN decreases or increases as the recording head 61 moves during the main scan, and the main scan is repeated. A certain nozzle 64 is used for printing. Therefore, this aspect can provide a printing apparatus capable of suppressing the above-described “wind pattern” phenomenon, and can provide a printing apparatus capable of improving the printing quality.

Here, the nozzle is a small hole from which an ink droplet is ejected. The ink droplets include uncolored ink such as ink droplets that improve image quality.
A print substrate is a material that holds a printed image. The shape is generally rectangular, but there are round shapes (for example, optical disks such as CD-ROM and DVD), triangles, squares, polygons, etc., and at least JIS (Japanese Industrial Standards) P0001: 1998 (paper / paperboard) And pulp and paper products) and all processed products. Resin sheets, metal plates, three-dimensional objects, etc. are also included in the substrate.
The main scanning means an operation from the stop state until the recording head moves in the main scanning direction and stops.
The relative movement of the recording head and the substrate includes that the substrate is moved without moving the recording head, that the recording head is moved without moving the substrate, and that both the substrate and the recording head are moved. Includes moving.
The decrease or increase in the nozzle usage range as the recording head moves means that the number of nozzles in the nozzle usage range decreases when the recording head moves by N pixels (N is a positive real number). The number of pixels N may be an integer or a decimal (a real number that is not an integer). The number of pixels N may be a fixed number or a variable number.
In addition, the remarks of the said aspect 1 are the same also in the following aspects.

[Aspect 2] (illustrated in FIGS. 2 to 4)
The control unit U1 may narrow the nozzle use range RN at the end of the main scan than the nozzle use range RN at the start of the main scan.

In other words, the present technology includes a recording head 61 having a nozzle row 68 in which a plurality of nozzles 64 are arranged in a direction (for example, the arrangement direction D1) different from the main scanning direction D2.
A main scanning unit 55 that repeats main scanning for moving the recording head 61 in the main scanning direction D2 with respect to the substrate ME1;
A sub-scanning unit (for example, a paper feed mechanism 53) that relatively moves the recording head 61 and the substrate ME1 in a sub-scanning direction D3 different from the main scanning direction D2.
A range in which the nozzles 64 are used in the nozzle row 68 is defined as a nozzle use range RN, and the nozzle use range RN at the end of the main scan is narrower than the nozzle use range RN at the start of the main scan. There is also an aspect of a printing apparatus including a control unit U1 that repeats the main scanning and performs printing using the nozzles 64 in the nozzle use range RN in the nozzle row 68.

In aspect 2, the main scan is repeated so that the nozzle use range RN at the end of the main scan is narrower than the nozzle use range RN at the start of the main scan, and the nozzles in the nozzle use range RN in the nozzle row 68 64 is used for printing. In this aspect, the “wind pattern” phenomenon that occurs before and after the end of the main scan is suppressed, so that it is possible to provide a technique that can further improve the print quality.
Here, narrowing the nozzle use range includes eliminating the nozzle use range. This appendix also applies to the following aspects.

[Aspect 3] (illustrated in FIGS. 2 to 4)
In the forward main scanning (for example, pass Pn1) in which the recording head 61 moves in the forward direction D21 in the main scanning direction D2, the control unit U1 is more than the nozzle use range RN at the start of the forward main scanning. The nozzle use range RN at the end of the forward main scan may be narrowed. Further, the control unit U1 determines the nozzle use range RN at the start of the backward main scanning in the backward main scanning (for example, pass Pn2) in which the recording head 61 moves in the backward direction D22 in the main scanning direction D2. Alternatively, the nozzle usage range RN at the end of the backward main scan may be narrowed. This aspect can provide a technique capable of speeding up printing while suppressing the “wind ripple” phenomenon.
Although not included in the above-described aspect 3, a case where printing is limited to forward main scanning (so-called unidirectional printing) is also included in the present technology.

[Aspect 4] (illustrated in FIGS. 7 to 9)
The control unit U1 may make the nozzle use range RN at the end of the main scan wider than the nozzle use range RN at the start of the main scan.

In other words, the present technology includes a recording head 61 having a nozzle row 68 in which a plurality of nozzles 64 are arranged in a direction (for example, the arrangement direction D1) different from the main scanning direction D2.
A main scanning unit 55 that repeats main scanning for moving the recording head 61 in the main scanning direction D2 with respect to the substrate ME1;
A sub-scanning unit (for example, a paper feed mechanism 53) that relatively moves the recording head 61 and the substrate ME1 in a sub-scanning direction D3 different from the main scanning direction D2.
A range in which the nozzles 64 are used in the nozzle row 68 is defined as a nozzle use range RN so that the nozzle use range RN at the end of the main scan is wider than the nozzle use range RN at the start of the main scan. There is also an aspect of a printing apparatus including a control unit U1 that repeats the main scanning and performs printing using the nozzles 64 in the nozzle use range RN in the nozzle row 68.

In the above aspect 4, the main scan is repeated so that the nozzle use range RN at the end of the main scan is wider than the nozzle use range RN at the start of the main scan, and the nozzles in the nozzle use range RN in the nozzle row 68 64 is used for printing. In this aspect, a “wind pattern” phenomenon that occurs immediately after the start of main scanning is suppressed, and therefore a technique capable of further improving print quality can be provided.
Here, the fact that there is no nozzle use range at the start of main scanning is also included in this embodiment. This appendix also applies to the following aspects.

[Aspect 5] (illustrated in FIGS. 7 to 9)
In the forward main scanning (for example, pass Pn1) in which the recording head 61 moves in the forward direction D21 in the main scanning direction D2, the control unit U1 is more than the nozzle use range RN at the start of the forward main scanning. The nozzle use range RN at the end of the forward main scan may be widened. Further, the control unit U1 determines the nozzle use range RN at the start of the backward main scanning in the backward main scanning (for example, pass Pn2) in which the recording head 61 moves in the backward direction D22 in the main scanning direction D2. In addition, the nozzle use range RN at the end of the backward main scan may be widened. This aspect can provide a technique capable of speeding up printing while suppressing the “wind ripple” phenomenon.
Although not included in the above-described aspect 5, the present technology also includes a case where printing is limited to forward main scanning (so-called unidirectional printing).

[Aspect 6] (illustrated in FIGS. 2 to 9)
The main scanning unit 55 may repeat the main scanning while the recording head 61 and the substrate ME1 are relatively moving in the sub-scanning direction D3. This aspect can provide a technique capable of speeding up printing while improving print quality.

[Aspect 7] (illustrated in FIGS. 13, 14, etc.)
The control unit U1 sets the first setting to repeat the main scan so that the change period T0 is included during the main scan, and whether the change period T0 exists during the repeated main scan. Or a selection unit U2 that selects any one of a plurality of settings including a second setting in which the change in the nozzle usage range RN in the change period T0 included is smaller than the first setting. You may have. The control unit U1 may perform printing using the nozzles 64 in the nozzle use range RN according to the selected setting. In this aspect, since printing can be performed using the nozzles 64 in the nozzle use range RN according to a setting selected from a plurality of settings, convenience is improved.

[Aspect 8] (illustrated in FIGS. 13 and 14)
The selection unit U2 may determine whether to select the first setting based on image data DA1 representing an image to be printed (for example, the print image IM1). This aspect can provide a suitable technique for improving the print quality.

[Aspect 9]
By the way, in the present technology, a recording head 61 having a nozzle row 68 in which a plurality of nozzles 64 are arranged in a direction different from the main scanning direction D2 (for example, the arrangement direction D1) moves in the main scanning direction D2 with respect to the substrate ME1. A printing method for performing sub-scanning in which the recording head 61 and the printing medium ME1 are relatively moved in a sub-scanning direction D3 different from the main scanning direction D2, The main scanning is repeated so that the nozzle usage range RN is included in the nozzle usage range RN, and a change period T0 in which the nozzle usage range RN decreases or increases as the recording head 61 moves during the main scanning. It has the aspect of the printing method which prints using the nozzle 64 which exists in the said nozzle use range RN among the said nozzle rows 68. FIG. This aspect can provide a printing method capable of improving the print quality.
Moreover, this technique also has the aspect of the printing method corresponding to the said aspects 2-8.

  Furthermore, the present technology provides a print control device that controls a printing unit including a recording head, a main scanning unit, and a sub-scanning unit, a composite device including the print control device, a composite device including the printing device, and a control method for the printing unit. The present invention can be applied to a control method for the composite apparatus, a control program for the printing unit, a control program for the composite apparatus, a computer-readable medium on which the control program is recorded, and the like. The aforementioned apparatus may be composed of a plurality of distributed parts.

(2) Specific example of configuration of printing apparatus:
FIG. 1 schematically illustrates a configuration example of a printing apparatus. The printing apparatus 1 shown in FIG. 1 is represented as a printing system (broadly defined printing apparatus) including components of the present technology, includes at least a narrowly defined inkjet printer 2 as a sales unit, and may include a host apparatus 100 and the like. Shall. FIG. 1 also shows a configuration example of a serial printer as the ink jet printer 2. A printing apparatus to which the present technology can be applied may include a copying machine, a facsimile, a multifunction machine having these functions, and the like. Examples of the ink used in the ink jet printer that forms a color image include C (cyan), M (magenta), Y (yellow), and K (black) inks. Of course, the ink further includes Lc (light cyan), Lm (light magenta), Dy (dark yellow), Lk (light black), R (red), Or (orange), Gr (green), for improving image quality. Uncolored ink, etc. may be included.

  FIG. 2 schematically shows an example of an operation of ejecting (ejecting) ink droplets (droplets) 67 from the recording head 61 in the forward main scan to form the dots DT0 on the substrate ME1. FIG. 3 schematically shows an example of an operation of ejecting ink droplets 67 from the recording head 61 in the backward main scanning to form the dots DT0 on the substrate ME1. For convenience, in FIGS. 2 and 3, circles 1 to 10 are added to the nozzles 64 of the nozzle array 68 in order from the top, and circles 1 to 10 are also added to the ink dots DT 0 corresponding to the nozzles 64. ing. Hereinafter, the recording head is also simply referred to as a head.

  The nozzle row 68 shown in FIGS. 2 and 3 is schematically shown as a row of nozzles 64 that eject ink of any color (for example, any one of C, M, Y, and K). Of course, in the head 61, a plurality of nozzle rows may be arranged in the sub-scanning direction D3. Since the number of nozzles 64 in the nozzle row 68 is usually more than ten, it is not limited to ten. The arrangement direction D1 of the nozzles 64 of the nozzle array 68 is orthogonal to the main scanning direction D2 (horizontal direction) in FIGS. 2 and 3, but the present technology also includes a case where the nozzles 68 are not orthogonal if they intersect the main scanning direction. . The alignment direction D1 coincides with the sub-scanning direction D3 (vertical direction) in FIGS. 2 and 3, but the present technology also includes a case where the alignment direction D1 and the sub-scanning direction D3 are different from each other. Furthermore, although the main scanning direction D2 and the sub-scanning direction D3 are orthogonal to each other in FIGS.

When the ink droplet 67 ejected from the nozzle 64 lands on the substrate ME1, a dot DT0 is formed. For example, when the ink droplet 67 ejected from the nozzle 1 of the circle 1 lands on the substrate ME1, dots DT0 are formed at the locations marked with the circle 1.
It should be noted that even a nozzle row in which nozzles are arranged in a staggered manner is included in the present technology. In this case, the arrangement direction D1 means the arrangement direction of the nozzles in each row in the staggered arrangement.

  The inkjet printer 2 shown in FIG. 1 includes a controller 10, a RAM (Random Access Memory) 20, a nonvolatile memory 30, a mechanism unit 50, interfaces (I / F) 71 and 72, an operation panel 73, and the like. The controller 10, the RAM 20, the nonvolatile memory 30, the I / Fs 71 and 72, and the operation panel 73 can input and output information with each other.

The controller 10 includes a CPU (Central Processing Unit) 11, a resolution conversion unit 41, a color conversion unit 42, a halftone processing unit 43, a signal transmission unit 44, and the like. Note that at least a part of the functions of these processing units (41 to 44) may be realized in the host device 100. The controller 10 can be configured by SoC (System on a Chip) or the like.
The CPU 11 is a device that mainly performs information processing and control in the inkjet printer 2.

The resolution conversion unit 41 converts the resolution of an image obtained from the host device 100, the memory card 90, or the like into a print resolution (for example, 720 × 720 dpi or 360 × 360 dpi). The obtained image is represented by, for example, RGB data having 256 gradation integer values of RGB (red, green, and blue) for each pixel. When the obtained image is not RGB data, the obtained image may be converted into RGB data.
For example, the color conversion unit 42 converts RGB data having a print resolution into CMYK data (an example of image data DA1) having an integer value of 256 gradations of CMYK (cyan, magenta, yellow, and black) for each pixel. Convert.

The halftone processing unit 43 performs a predetermined halftone process such as a dither method, an error diffusion method, or a density pattern method on the gradation values of each pixel constituting the CMYK data to reduce the number of gradation values. The halftone data DA2 is generated. The halftone data DA2 is data representing the dot formation status of each pixel corresponding to the print image IM1, and can be, for example, binary data representing the presence or absence of dot formation for each pixel. The halftone data DA2 can correspond to dots of different sizes such as quaternary data in which 0 is not present, 1 is small dot formation, 2 is medium dot formation, and 3 is large dot formation. Multi-value data with gradation or higher may be used.
The signal transmission unit 44 generates a drive signal SG corresponding to the voltage signal applied to the drive element 63 of the head 61 based on the halftone data DA2, and outputs it to the drive circuit 62. If necessary, the halftone data DA2 may be rearranged in the order in which dots are formed by the mechanism unit 50.

  Each of the units 41 to 44 may be configured by an ASIC (Application Specific Integrated Circuit), and may directly read data to be processed from the RAM 20 or directly write processed data to the RAM 20.

  The mechanism unit 50 controlled by the controller 10 includes a paper feed mechanism 53 (an example of a sub-scanning unit), a main scanning unit 55, a head 61, and the like. The main scanning unit 55 includes a carriage motor 56, a belt 57, a carriage 60, and the like. The carriage motor 56 reciprocates the carriage 60 in the main scanning direction D2 via a plurality of gears and a belt 57 (not shown). The paper feed mechanism 53 carries the substrate ME1 in the paper feed direction D31 (sub-scanning direction D3). 2 and 3 is the upward direction. For example, a head 61 that discharges CMYK ink droplets 67 is mounted on the carriage 60. The head 61 includes a drive circuit 62, a drive element 63, and the like. The drive circuit 62 applies a voltage signal to the drive element 63 in accordance with the drive signal SG input from the controller 10. The driving element 63 includes a piezoelectric element that applies pressure to the ink 66 (an example of a liquid) in the pressure chamber that communicates with the nozzle 64, a driving element that generates bubbles in the pressure chamber by heat and ejects ink droplets 67 from the nozzle 64, Etc. can be used. Ink 66 is supplied to the pressure chamber of the head 61 from an ink cartridge 65 (an example of a liquid cartridge). A combination of the ink cartridge 65 and the head 61 is provided in each of CMYK, for example. The ink 66 in the pressure chamber is ejected as an ink droplet 67 from the nozzle 64 toward the substrate ME1 by the driving element 63, and a dot DT0 of the ink droplet 67 is formed on the substrate ME1 such as printing paper. A print image IM1 with a plurality of dots DT0 is formed on the substrate ME1.

The RAM 20 stores a program PRG2 and the like that cause the printing apparatus 1 to realize the function of the control unit U1.
The nonvolatile memory 30 stores program data PRG1 and the like developed on the RAM 20. As the nonvolatile memory 30, a magnetic recording medium such as a ROM (Read Only Memory), a flash memory, or a hard disk is used. The expansion of the program data PRG1 means that the program PRG2 that can be interpreted by the CPU 11 is written in the RAM 20.

The card I / F 71 is a circuit that writes data to the memory card 90 and reads data from the memory card 90.
The communication I / F 72 is connected to the communication I / F 172 of the host device 100 and inputs / outputs information to / from the host device 100. A display device 174 or the like may be connected to the host device 100. The host device 100 includes a computer such as a personal computer (including a tablet terminal), a digital camera, a digital video camera, a mobile phone such as a smartphone, and the like.

The operation panel 73 includes an output unit 74, an input unit 75, and the like, and a user can input various instructions to the inkjet printer 2. The output unit 74 includes, for example, a liquid crystal panel (display unit) that displays information corresponding to various instructions and information indicating the state of the inkjet printer 2. The output unit 74 may output the information as a voice. The input unit 75 includes, for example, operation keys (operation input unit) such as a cursor key and a determination key. The input unit 75 may be a touch panel that accepts an operation on the display screen.
The above-described controller 10 corresponds to the selection unit U2 together with the operation panel 73 and the host device 100. The controller 10 corresponds to the control unit U1 together with the mechanism unit 50, the operation panel 73, and the host device 100. Here, the mechanism unit 50 including the main scanning unit 55 and the paper feeding mechanism 53, and the head 61 are referred to as a printing unit U0.

(3) First specific example of recording method:
First, a first example of a recording method included in the present technology will be described with reference to FIGS.
FIG. 2 shows the head 61 that moves in the forward direction D21 and the ink dots DT0 formed on the substrate ME1 in the forward main scan of the Pn1 pass among the main scans that are repeated in a state where paper is always fed. Is shown. FIG. 3 shows the head 61 that moves in the backward direction D22 and the ink dot DT0 formed on the substrate ME1 in the backward main scan of the Pn2 pass following the Pn1 pass while the paper is always fed. ing. FIG. 4 schematically shows an example of a print area for each pass formed on the substrate ME1.

  The head 61 has a nozzle row 68 in which a plurality of nozzles 64 are arranged in an arrangement direction D1 orthogonal to the main scanning direction D2. The main scanning unit 55 repeats main scanning for reciprocating the recording head 61 in the main scanning direction D2 with respect to the substrate ME1. The paper feed mechanism 53 moves the substrate ME1 with respect to the head 61 in the sub scanning direction D3. The paper feed mechanism 53 shown in FIGS. 2 to 4 always moves the substrate ME1 in the paper feed direction D31 (upward in FIGS. 2 to 4), which is one direction of the sub-scanning direction D3. For this reason, the main scanning unit 55 repeats the main scanning while the substrate ME1 is moving in the paper feed direction D31. The control unit U1 repeats the main scan so that the change period T0 in which the nozzle use range RN decreases as the recording head 61 moves during the main scan, and is in the nozzle use range RN in the nozzle row 68. Printing is performed using the nozzle 64.

First, the nozzle use range RN and the dot formation scheduled position in the forward main scan of the Pn1 pass will be described with reference to FIG. For easy understanding, it is assumed that the printing medium ME1 moves by 0.5 pixels in the paper feed direction D31 when the head 61 moves by 1 pixel in the forward direction D21.
The nozzle use range RN at the start of forward main scanning is the nozzles 64 from circle 1 to circle 10. Therefore, the planned dot formation positions, which are the planned landing positions of the ink droplets ejected from each nozzle 64, are the positions of the dots DT0 from the circle 1 to the circle 10 in the state ST1.

When the head 61 moves from the state ST1 by one pixel in the forward direction D21 (state ST2), the substrate ME1 moves by 0.5 pixels in the paper feed direction D31. In this specific example, since the length of the dot formation scheduled position in the sub-scanning direction D3 is slightly shorter than the state ST1 (from circle 1 to circle 10), the nozzle use range RN is limited to the nozzles from circle 1 to circle 9. doing. Therefore, the dot formation scheduled positions in the state ST2 are the positions of dots from circle 1 to circle 9.
When the head 61 moves from the state ST2 by one pixel in the forward direction D21 (state ST3), the substrate ME1 further moves by 0.5 pixels in the paper feed direction D31. In order to further shorten the length of the dot formation scheduled position in the sub-scanning direction D3, in the state ST3, the nozzle use range RN is limited to the nozzles from the circle 1 to the circle 8, and the dot formation scheduled positions are from the circle 1 to the circle 8. It is the position of the dot.

Thereafter, the same operation is repeated. For example, in the state ST5 in which the head 61 has moved by two pixels in the forward direction D21 from the state ST3, the nozzle use range RN is limited to the nozzles from the circle 1 to the circle 6, and the dot formation scheduled positions are from the circle 1 to the circle 6 This is the dot position.
The nozzle use range RN at the end of the forward main scan is only the circle 1 nozzle, and the dot formation scheduled position is only the position of the circle 1 dot in the state ST10. Therefore, the control unit U1 narrows the nozzle use range RN at the end of the forward main scan from the nozzle use range RN at the start of the forward main scan. As a result, an isosceles triangle-shaped print region Rn1 is formed on the substrate ME1 with two oblique sides having the same length and the remaining sides on the left side of FIG. 2, and a dot DT0 is formed in the print region Rn1. The The feed amount of the substrate ME1 in the paper feed direction D31 is about ½ of the first nozzle use range RN.

Next, the nozzle use range RN and the dot formation scheduled position in the backward main scan in the Pn2 pass will be described with reference to FIG. For the sake of easy understanding, it is assumed that when the head 61 moves by one pixel in the backward direction D22, the substrate ME1 moves by 0.5 pixels in the paper feeding direction D31.
The nozzle use range RN at the start of the backward main scan is the nozzles 64 from the circle 1 to the circle 10. Therefore, the dot formation scheduled position is the position of the dot DT0 from the circle 1 to the circle 10 in the state ST1 of FIG.

When the head 61 moves from the state ST1 in FIG. 3 by one pixel in the backward direction D22 (state ST2), the substrate ME1 moves by 0.5 pixels in the paper feed direction D31. Here, since there are two dot formation scheduled positions in the forward main scanning, in the state ST2, the nozzle use range RN is limited to the nozzles from the circle 1 to the circle 9, and the dot formation scheduled positions are from the circle 1 to the circle 9. It is the position of the dot up to.
When the head 61 moves from the state ST2 in FIG. 3 by one pixel in the backward direction D22 (state ST3), the substrate ME1 further moves by 0.5 pixels in the paper feed direction D31. Here, since there are three dot formation scheduled positions in the forward main scanning, in the state ST3, the nozzle use range RN is limited to the nozzles from the circle 1 to the circle 8, and the dot formation scheduled positions are from the circle 1 to the circle 8. It is the position of the dot up to.

  Thereafter, the same operation is repeated. The nozzle use range RN at the end of the backward main scanning is only the circle 1 nozzle, and the dot formation scheduled position is only the position of the circle 1 dot in the state ST10 in FIG. Accordingly, the control unit U1 narrows the nozzle use range RN at the end of the backward main scan from the nozzle use range RN at the start of the backward main scan. As a result, an isosceles triangular print region Rn2 is formed on the printing medium ME1 with two oblique sides having equal lengths and the remaining sides on the right side of FIG. 3, and dots DT0 are formed in the print region Rn2. The The feed amount of the substrate ME1 in the paper feed direction D31 is about ½ of the first nozzle use range RN.

The forward main scanning and the backward main scanning described above are further repeated. FIG. 4 schematically shows an example of each print area of the print image IM1 that is formed on the substrate ME1 by repeating the forward main scan and the reverse main scan starting from the pass P1. FIG. 4 shows the position of the head 61 relative to the substrate ME1 in each of the passes P1 to P9, and shows an example in which triangular print areas R1 to R9 are formed in each of the passes P1 to P9. Here, passes P1, P3, P5, P7, and P9 are forward main scans, passes P2, P4, P6, and P8 are backward main scans, and the first pass P1 is the sub-scan direction D3 of the print image IM1. The printing region R1 has a right triangle shape in order to form the leading end portion of the print image IM1, and the last pass P9 has a printing region R9 in the right triangle shape to form the rear end portion in the sub-scanning direction D3 of the print image IM1. It has become. In passes P2, P3,..., P8, isosceles triangular print regions R2, R3,..., R8 are formed while alternately changing the direction in the main scanning direction D2. Therefore, the passes P1 to P9 are a change period T0 in which the nozzle use range RN decreases as the head 61 moves in all the main scans.
As described above, the print image IM1 is efficiently formed on the substrate ME1.

  Actually, it is assumed that the length of the print image IM1 in the sub-scanning direction D3 is considerably longer than the length of the nozzle row 68 in the main scanning direction D2. Even in such a case, the present technology can be applied.

FIG. 5 shows the head 61 that moves in the forward direction D21 and the ink dots DT0 formed on the substrate ME1 in the forward main scan of the Pn1 pass among the main scans that are repeated in a state where paper is always fed. Show. In the example shown in FIG. 5, when the head 61 moves one pixel in the forward direction D21, the substrate ME1 moves 0.2 pixels in the paper feed direction D31. Also in this case, by gradually reducing the number of nozzles used from the 10 round nozzles, a substantially isosceles triangular print area is formed while alternately changing the direction in the main scanning direction D2, and each pass is performed in all of the main scanning. The nozzle use range RN is a change period T0 that decreases stepwise as the head 61 moves.
Note that in the backward main scanning of the Pn2 pass, a printing area is formed in which the printing area Rn1 shown in FIG. Therefore, as in the example shown in FIG. 4, the print areas R1, R2, R3,... Are formed in the paths P1, P2, P3,.

  In the example shown in FIGS. 2, 3, and 5, the dot formation scheduled position is smaller than one pixel in the sub-scanning direction D <b> 3. Therefore, when the gradation value (for example, an integer value of 0 to 255) of each pixel PX1 of the image data DA1 (for example, CMYK data) representing the print image IM1 is converted into the halftone data DA2, each pixel PX2 of the halftone data DA2 is converted. You may shift in the subscanning direction D3 according to a dot formation scheduled position.

FIG. 6 schematically shows an example in which each pixel PX2 of the halftone data DA2 converted from the image data DA1 is matched with the dot formation scheduled position shown in FIG. In FIG. 6, pixels PX1 and PX2 surrounded by a thick line are pixels on which no deviation occurs in the planned dot formation position by design. The four pixels between the thick line pixels in the main scanning direction D2 are shifted by −0.2 pixel, −0.4 pixel, +0.4 pixel, and +0.2 pixel, respectively, with respect to the paper feed direction D31. Yes. In this way, each pixel PX2 of the halftone data DA2 can be associated with the planned dot formation position, and a drive signal SG for ejecting ink droplets that land on the planned dot formation position can be generated from the halftone data DA2. it can.
Of course, in the example shown in FIGS. 2 and 3, if each pixel PX2 of the halftone data DA2 is shifted in accordance with the dot formation planned position in the same manner, an ink droplet is generated by generating a drive signal SG from the halftone data DA2. It is possible to land on the dot formation scheduled position.

When bi-directional printing is performed so that a rectangular print area is formed on a band basis while the paper feed of the substrate is stopped, the forward main scan print area and the reverse main scan print area “Color unevenness” due to a difference in the landing order of ink droplets may occur between print areas. In addition, “streaks” along the main scanning direction may occur due to variations in the amount of paper to be fed once in the substrate to be conveyed intermittently in the sub-scanning direction.
In the specific example described above, since the main scanning is repeated while the substrate ME1 is continuously conveyed in the paper feed direction D31, the printing speed is increased, and the above-described “color unevenness” becomes difficult to understand, and “streaks”. Is less likely to occur. Further, in this specific example, the main scan is repeated so that the nozzle use range RN decreases as the head 61 moves during the main scan, and the nozzles 64 in the nozzle use range RN in the nozzle row 68 are used. Printing is performed. By reducing the number of nozzles used in the second half of the main scan, the “wind pattern” phenomenon due to the high discharge density of the ink droplets discharged from the head 61 is suppressed before and after the end of the main scan. Since the “wind pattern” phenomenon that tends to occur before and after the end of the main scan of the head 61 is suppressed before and after the end of the main scan, the print quality of this example further improves in high-speed printing.

(4) Second specific example of recording method:
In repeated main scans, the nozzle use range RN at the end of the main scan can be made wider than the nozzle use range RN at the start of the main scan.

  FIG. 7 shows the head 61 that moves in the forward direction D21 and the ink dots DT0 formed on the substrate ME1 in the forward main scan of the Pn1 pass among the main scans that are repeated in a state where paper is always fed. Is shown. FIG. 8 shows the head 61 that moves in the backward direction D22 and the ink dots DT0 that are formed on the substrate ME1 in the backward main scan of the Pn2 pass following the Pn1 pass while the paper is always fed. ing. FIG. 9 schematically shows an example of a print area for each pass formed on the substrate ME1.

  7-9, the paper feed mechanism 53 always moves the substrate ME1 in the paper feed direction D31, and the main scanning unit 55 repeats main scanning while the substrate ME1 is moving. The control unit U1 repeats the main scan so that the nozzle use range RN includes a change period T0 that increases as the head 61 moves during the main scan, and the nozzles in the nozzle use range RN in the nozzle row 68 are included. 64 is used for printing.

FIG. 7 shows that when the head 61 moves by one pixel in the forward direction D21, the substrate ME1 moves by 0.5 pixels in the paper feed direction D31, and the nozzle use range RN and dots in the forward main scan of the Pn1 pass. The formation position is shown.
At the start of forward main scanning, the nozzle use range RN is only the nozzle 64 with the circle 10, and the dot formation scheduled position is only the position of the dot DT0 with the circle 10 in the state ST1.

When the head 61 moves from the state ST1 by one pixel in the forward direction D21 (state ST2), the substrate ME1 moves by 0.5 pixels in the paper feed direction D31. In this specific example, in order to make the length of the dot formation scheduled position in the sub-scanning direction D3 slightly longer than the state ST1 (only the circle 10), the nozzle use range RN is expanded to the circle 9. Therefore, the dot formation scheduled positions in the state ST2 are the positions of the dots 9 and 10.
When the head 61 moves from the state ST2 by one pixel in the forward direction D21 (state ST3), the substrate ME1 further moves by 0.5 pixels in the paper feed direction D31. In order to further increase the length of the dot formation scheduled position in the sub-scanning direction D3, in the state ST3, the nozzle use range RN is expanded to the circle 8, and the dot formation scheduled position becomes the dot position from the circle 8 to the circle 10. Yes.

Thereafter, the same operation is repeated. For example, in the state ST5 in which the head 61 has moved by two pixels in the forward direction D21 from the state ST3, the nozzle use range RN is expanded to the circle 6, and the dot formation scheduled positions are the positions of the dots from the circle 6 to the circle 10. .
The nozzle use range RN at the end of the forward main scanning is expanded to the circle 1, and the dot formation scheduled position is the dot position from the circle 1 to the circle 10 in the state ST10. Therefore, the control unit U1 makes the nozzle use range RN at the end of the forward main scan wider than the nozzle use range RN at the start of the forward main scan. As a result, an isosceles triangle-shaped print region Rn1 is formed on the substrate ME1 with two oblique sides having the same length and the remaining sides on the right side of FIG. 7, and dots DT0 are formed in the print region Rn1. The The feed amount of the substrate ME1 in the paper feed direction D31 is about ½ of the first nozzle use range RN.

FIG. 8 shows that when the head 61 moves by one pixel in the backward direction D22, the substrate ME1 moves by 0.5 pixels in the paper feed direction D31, and the nozzle use range RN and dots in the backward main scan in the Pn2 pass. The formation position is shown.
At the start of backward main scanning, the nozzle use range RN is only the nozzle 64 with the circle 10, and the dot formation scheduled position is only the position of the dot DT0 with the circle 10 in the state ST1.

When the head 61 moves from the state ST1 by one pixel in the backward direction D22 (state ST2), the substrate ME1 moves by 0.5 pixels in the paper feed direction D31. Here, in order to make the length of the dot formation scheduled position in the sub-scanning direction D3 slightly longer than the state ST1 (only the circle 10), in the state ST2, the nozzle use range RN is expanded to the circle 9, and the dot formation scheduled position is round. The positions of dots 9 and 10 are circles.
When the head 61 moves from the state ST2 by one pixel in the backward direction D22 (state ST3), the substrate ME1 further moves by 0.5 pixels in the paper feed direction D31. In order to further increase the length of the dot formation scheduled position in the sub-scanning direction D3, in the state ST3, the nozzle use range RN is expanded to the circle 8, and the dot formation scheduled position becomes the dot position from the circle 8 to the circle 10. Yes.

  Thereafter, the same operation is repeated. The nozzle use range RN at the end of the backward main scan is expanded to the circle 1, and the dot formation scheduled positions are the positions of the dots 1 to 10 in the state ST10. Therefore, the control unit U1 makes the nozzle use range RN at the end of the backward main scan wider than the nozzle use range RN at the start of the backward main scan. As a result, an isosceles triangular print area Rn2 is formed on the printing medium ME1 with two oblique sides having equal lengths and the remaining sides on the left side of FIG. 7, and dots DT0 are formed in the print area Rn2. The The feed amount of the substrate ME1 in the paper feed direction D31 is about ½ of the first nozzle use range RN.

The forward main scanning and the backward main scanning described above are further repeated. FIG. 9 schematically shows an example of each print area of the print image IM1 that is formed on the substrate ME1 by repeating the forward main scan and the reverse main scan starting from the pass P1. FIG. 9 shows the position of the head 61 relative to the substrate ME1 in each of the passes P1 to P9, and shows an example in which triangular print areas R1 to R9 are formed in each of the passes P1 to P9. Here, passes P1, P3, P5, P7, and P9 are forward main scans, passes P2, P4, P6, and P8 are backward main scans, and the first pass P1 is the sub-scan direction D3 of the print image IM1. The printing region R1 has a right triangle shape in order to form the leading end portion of the print image IM1, and the last pass P9 has a printing region R9 in the right triangle shape to form the rear end portion in the sub-scanning direction D3 of the print image IM1. It has become. In passes P2, P3,..., P8, isosceles triangular print regions R2, R3,..., R8 are formed while alternately changing the direction in the main scanning direction D2. Therefore, the passes P1 to P9 are a change period T0 in which the nozzle use range RN increases as the head 61 moves in all the main scans.
As described above, the print image IM1 is efficiently formed on the substrate ME1.

  Even in the specific example described above, the main scanning is repeated while the substrate ME1 is continuously conveyed in the paper feeding direction D31, so that the printing is speeded up and the above-described “color unevenness” becomes difficult to understand, and “streak”. Is less likely to occur. Further, in this specific example, the main scan is repeated so that the nozzle use range RN increases as the head 61 moves during the main scan, and the nozzles 64 in the nozzle use range RN in the nozzle row 68 are used. Printing is performed. By reducing the number of nozzles used in the first half of the main scanning, the “wind pattern” phenomenon due to the high discharge density of the ink droplets discharged from the head 61 is suppressed immediately after the start of the main scanning. Since the “wind pattern” phenomenon that is likely to occur immediately after the start of the main scan of the head 61 is suppressed immediately after the start of the main scan, the print quality of this specific example is further improved in high-speed printing.

(5) Third specific example of recording method:
The present technology can also be applied to a case where a substrate is conveyed intermittently. For example, if the main scanning is performed in a state where the conveyance of the printing material is stopped and the printing material is fed by a predetermined amount after the dots of the predetermined printing area are formed and the conveyance is stopped, the printed image is displayed. Can be formed.

  In the upper part of FIG. 10, the head that moves in the forward direction D21 in the forward main scan of the Pn1 pass among the main scans that are repeated while the conveyance of the substrate ME1 that is intermittently fed is stopped. 61 and ink dots DT0 formed on the substrate ME1. The lower part of FIG. 10 shows the head 61 that moves in the backward direction D22 and the ink dots DT0 formed on the substrate ME1 in the backward main scan of the Pn2 pass following the Pn1 pass. An example of the print area for each pass formed on the substrate ME1 is the same as that in FIG. 4 and will be described with reference to FIG.

In the example shown in FIG. 10, the control unit U <b> 1 repeats the main scanning so that the change period T <b> 0 in which the nozzle usage range RN decreases as the recording head 61 moves during the main scanning. Printing is performed using the nozzles 64 in the nozzle usage range RN.
As shown in the upper part of FIG. 10, the nozzle use range RN at the start of the forward main scan is the nozzles 64 from circle 1 to circle 10, and the dot formation scheduled position in the state ST1 is the dots from circle 1 to circle 10 This is the position of DT0.

  After the state ST1 (3 pixels in the main scanning direction D2 in FIG. 10), the length of the dot formation scheduled position in the sub-scanning direction D3 is slightly shorter than that in the state ST1 (from circle 1 to circle 10). The range RN is limited to nozzles 2 to 9. Accordingly, the dot formation scheduled positions in the state ST2 are the dot positions from the circle 2 to the circle 9. Hereinafter, as the head 61 advances in the forward direction D21, the nozzle usage range RN is stepwise from circle 3 to circle 8 (state ST3), circle 4 to circle 7 (state ST4), circle 5 and circle 6 ( The state changes to state ST5) and none (state ST6). That is, the dot formation scheduled positions are stepwise from circle 3 to circle 8 (state ST3), circle 4 to circle 7 (state ST4), circle 5 and circle 6 (state ST5) in accordance with the progress of forward main scanning. ), None (state ST6).

  As shown in the lower part of FIG. 10, the nozzle use range RN at the start of backward main scanning is the nozzles 64 from circle 1 to circle 10, and the dot formation scheduled positions in the state ST11 are dots from circle 1 to circle 10 This is the position of DT0. Hereinafter, as the head 61 advances in the backward direction D22, the nozzle usage range RN is stepwise from circle 2 to circle 9 (state ST12), circle 3 to circle 8 (state ST13), circle 4 to circle 7 ( State ST14), circle 5 and circle 6 (state ST15), and none (state ST16). That is, the dot formation scheduled positions are stepwise from circle 2 to circle 9 (state ST12), circle 3 to circle 8 (state ST13), and circle 4 to circle 7 (state ST14) in accordance with the progress of forward main scanning. ), Circle 5 and circle 6 (state ST15), and none (state ST16).

The forward main scanning and the backward main scanning described above are further repeated. Thereby, triangular print areas (R1 to R9 in FIG. 4) are formed in each pass (P1 to P9 in FIG. 4). The passes P1 to P9 shown in FIG. 4 are a change period T0 in which the nozzle use range RN decreases as the head 61 moves in all the main scans.
As described above, the print image IM1 is efficiently formed on the substrate ME1.

In the specific example described above, the main scan is repeated so that the nozzle use range RN decreases as the head 61 moves during the main scan, and the nozzles 64 in the nozzle use range RN in the nozzle array 68 are used for printing. Is done. By reducing the number of nozzles used in the second half of the main scan, the “wind ripple” phenomenon that tends to occur before and after the main scan of the head 61 is suppressed before and after the end of the main scan. Further, in the sub-scanning direction D3, the print areas of the forward main scan are in contact with each other at the start part of the forward main scan, and the print areas of the backward main scan are in contact with each other at the start part of the backward main scan. The streak between the print area for the forward main scan and the print area for the backward main scan is difficult to understand. Therefore, in this example, the print quality is further improved.
Although not shown, the main scan can be repeated so that the change period T0 in which the nozzle usage range RN increases as the head 61 moves is included during the main scan. In this case, by reducing the number of nozzles used in the first half of the main scan, the “wind pattern” phenomenon that is likely to occur immediately after the start of the main scan of the head 61 is suppressed immediately after the start of the main scan. Further, in the sub-scanning direction D3, the print areas in the forward main scan are in contact at the end of the forward main scan, and the print areas in the backward main scan are in contact at the end of the backward main scan. The streak between the printing area for the direction main scanning and the printing area for the backward main scanning is difficult to understand. Accordingly, in this case, the print quality is further improved.

  Further, as illustrated in FIG. 11, there may be a used nozzle at the end of the main scanning. In the upper part of FIG. 11, the head that moves in the forward direction D21 in the forward main scan of the Pn1 pass among the main scans that are repeated while the conveyance of the substrate ME1 that is intermittently fed is stopped. 61 and ink dots DT0 formed on the substrate ME1. The lower part of FIG. 11 shows the head 61 that moves in the backward direction D22 and the ink dots DT0 formed on the substrate ME1 in the backward main scan of the Pn2 pass following the Pn1 pass. FIG. 12 schematically shows an example of a print area for each pass formed on the substrate ME1.

As shown in the upper part of FIG. 11, as the head 61 advances in the forward direction D21, the nozzle usage range RN gradually increases from circle 1 to circle 10 (state ST1) and from circle 2 to circle 9 (state ST2). , From circle 3 to circle 8 (state ST3) and from circle 4 to circle 7 (state ST4). That is, the dot formation scheduled positions are stepwise from circle 1 to circle 10 (state ST1), circle 2 to circle 9 (state ST2), and circle 3 to circle 8 (state) according to the progress of forward main scanning. ST3) and changes from circle 4 to circle 7 (state ST4). That is, the decreasing rate of the nozzle usage range RN in the change period T0 is smaller than the decreasing rate of the nozzle usage range RN shown in FIG.
Further, as shown in the lower part of FIG. 11, as the head 61 advances in the backward direction D22, the nozzle usage range RN is stepwise from circle 1 to circle 10 (state ST11) and from circle 2 to circle 9 (state ST12), from circle 3 to circle 8 (state ST13), and from circle 4 to circle 7 (state ST14). That is, the dot formation scheduled positions are stepwise from circle 1 to circle 10 (state ST11), from circle 2 to circle 9 (state ST12), and from circle 3 to circle 8 (state) as the forward main scan progresses. ST13) and changes from circle 4 to circle 7 (state ST14). That is, the decreasing rate of the nozzle usage range RN in the change period T0 is smaller than the decreasing rate of the nozzle usage range RN shown in FIG.

The forward main scanning and the backward main scanning described above are further repeated. Thereby, in the example shown in FIG. 12, trapezoidal print areas R1 to R7 are formed in the passes P1 to P7. Passes P <b> 1 to P <b> 7 shown in FIG. 12 are a change period T <b> 0 in which the nozzle use range RN decreases as the head 61 moves in all main scans.
As described above, the print image IM1 is efficiently formed on the substrate ME1.

In the specific example described above, since the use nozzle is present at the end of the main scanning, the paper feed amount can be increased. Therefore, this example can speed up printing while suppressing the “wind ripple” phenomenon.
Of course, when the used nozzles are left at the end of the main scanning, the main scanning can be repeated so that the change period T0 in which the nozzle use range RN increases as the head 61 moves is included during the main scanning. In this case, the increase rate of the nozzle use range RN in the change period T0 is smaller than the increase rate of the nozzle use range RN when no use nozzle is left at the end of the main scan.

(6) Fourth specific example of recording method:
The printing method for performing the main scanning having the change period T0 described above may or may not be performed depending on conditions. For example, if there is a region where the ink droplet ejection density is greater than or equal to the threshold value in the print image, a printing method that performs main scanning having a change period T0 is performed, and there is no region where the ink droplet ejection density is greater than or equal to the threshold value. For example, a printing method that performs main scanning without the change period T0 may be implemented.

FIG. 13 shows the first setting in which the main scanning is repeated so that the change period T0 is included during the main scanning, or during the main scanning which is repeated except for the leading edge and the trailing edge of the print image IM1. Shows an example of a setting selection process for selecting whether to set the second setting without the change period T0 based on the image data DA1. This process is performed by the controller 10 of the inkjet printer 2. The image data DA1 is assumed to be CMYK data. The controller 10 that performs the processes of steps S102 to S108 corresponds to the selection unit U2. Hereinafter, the description of “step” is omitted. FIG. 13 also shows an example in which the image data DA1 is divided into a plurality of areas DA1i.
Note that the processing according to the present embodiment is not limited to the example executed by the CPU, and may be executed by another electronic component [for example, ASIC (Application Specific Integrated Circuit)]. Further, the processing according to the present embodiment may be distributed by a plurality of CPUs, or may be executed by the CPU and an electronic component (for example, ASIC) operating in cooperation.

  When the process is started, the controller 10 divides the image data DA1 into a plurality of areas DA1i having a predetermined number of pixels, and calculates the ink ejection amount Ii for each area DA1i (S102). The ink discharge amount Ii may be an ink discharge amount combined with CMYK, or may be an ink discharge amount divided into CMYK. For example, when the C ink ejection amount is calculated in a certain area DA1i, the arithmetic average of the C pixel values of the pixels included in the area DA1i can be used as the C ink ejection amount. The same applies when calculating the M, Y, and K ink ejection amounts. When calculating the ink discharge amount combining CMYK, for example, an arithmetic average of C, M, Y, and K ink discharge amounts can be used.

  When the ink discharge amount Ii for each region is calculated, the controller 10 branches the process depending on whether or not the maximum value Max (Ii) of the ink discharge amount Ii is equal to or greater than the threshold value TH1 (S104). However, the threshold value TH1 is a predetermined value that is larger than the minimum pixel value and smaller than the maximum pixel value. Max (Ii) ≧ TH1 means that there is a region DA1i where the ink droplet ejection density is relatively high, and Max (Ii) <TH1 means that the ink droplet ejection density is in all the regions DA1i. Means relatively low.

When Max (Ii) ≧ TH1, the controller 10 selects the first setting for repeating the main scan so that the change period T0 is included during the main scan (see, for example, FIG. 4). According to the setting, printing is executed using the nozzles 64 in the nozzle use range RN (S106), and the setting selection process is terminated. Thereby, when there is a region DA1i where the discharge density of ink droplets is relatively high, the “wind pattern” phenomenon is suppressed, and the print image quality is improved.
On the other hand, if Max (Ii) <TH1, the controller 10 selects the second setting in which there is no change period T0 during the main scan except for the leading edge and the trailing edge of the print image IM1, and this first According to the second setting, printing is executed using the nozzles 64 in the nozzle use range RN (S108), and the setting selection process is terminated. Accordingly, it is possible to increase the printing speed when there is no area DA1i where the discharge density of ink droplets is relatively high.

  In the specific example described above, printing is performed in accordance with a setting selected from a plurality of settings, so that convenience is improved. In addition, the printing speed is increased when it is not necessary to repeat the main scanning so that the change period T0 is included during the main scanning while improving the printing quality.

  Further, as illustrated in FIG. 14, there may be three or more selection target settings. FIG. 14 shows a first setting in which main scanning is repeated so that the nozzle usage range RN changes relatively large during the main scanning, or the nozzle usage range RN changes relatively small during the main scanning. Whether to set the second setting to repeat main scanning, or to set to the third setting in which there is no change period T0 during the main scanning repeated except for the leading edge and the trailing edge of the print image IM1. 2 shows an example of setting selection processing to be selected based on the above. That is, in the second setting of this example, the change in the nozzle use range RN in the change period T0 included during repeated main scanning is smaller than that in the first setting.

  When the process is started, the controller 10 divides the image data DA1 into a plurality of areas DA1i having a predetermined number of pixels, and calculates an ink ejection amount Ii for each area DA1i (S202). When the ink discharge amount Ii for each region is calculated, the controller 10 branches the process according to the maximum value Max (Ii) of the ink discharge amount Ii (S204). The threshold values TH1 and TH2 are used for the determination process in S204. However, the thresholds TH1 and TH2 are larger than the minimum pixel value and smaller than the maximum pixel value, and TH1 <TH2.

When Max (Ii) ≧ TH2, the controller 10 repeats the main scan so that the change period T0 is included during the main scan, and the nozzle use range RN is changed relatively large during the main scan. The first setting is selected (see, for example, FIG. 4), printing is performed using the nozzles 64 in the nozzle usage range RN according to the first setting (S206), and the setting selection process is terminated. Thereby, when there is a region DA1i where the discharge density of ink droplets is relatively high, the “wind pattern” phenomenon is suppressed, and the print image quality is improved.
When TH1 ≦ Max (Ii) <TH2, the controller 10 includes the change period T0 during the main scanning, and performs the main scanning so that the nozzle usage range RN is changed relatively small during the main scanning. Is selected (see, for example, FIG. 12), printing is performed using the nozzles 64 in the nozzle usage range RN according to the second setting (S208), and the setting selection process is terminated. As a result, when the maximum discharge density of ink droplets is lower than when Max (Ii) ≧ TH2, but there is a relatively high area DA1i, printing can be speeded up while suppressing the “wind pattern” phenomenon. It becomes.

When Max (Ii) <TH2, the controller 10 selects the third setting without the change period T0 during the main scan except for the leading edge and the trailing edge of the print image IM1, and this third Printing is executed using the nozzles 64 in the nozzle usage range RN according to the setting (S210), and the setting selection process is terminated. Thereby, it is possible to further increase the printing speed when there is no area DA1i where the discharge density of ink droplets is relatively high.
In the specific example described above, printing can be performed more efficiently.

  Note that the selection of the setting may be based on an operation by the user in addition to the image data. Referring to FIG. 1, for example, a user operation for displaying a plurality of settings on the output unit 74 of the operation panel 73 or the display device 174 of the host device 100 and selecting one of these settings is performed. When received by the input unit 75 of the operation panel 73 or the host device 100, printing can be performed using the nozzles in the nozzle use range RN according to the received setting.

(7) Modification:
Various modifications can be considered for the present invention.
For example, in the sub-scanning, the recording head and the printing material only need to move relative to each other in the sub-scanning direction, and the printing material does not move in addition to the recording head that does not move in the sub-scanning direction. The recording head may move in the sub-scanning direction, and both the recording head and the printing material may move in the sub-scanning direction.
The change period included in the main scan may be a part of the main scan.

  FIG. 15 schematically illustrates an example of the print area for each pass when the main scanning to be repeated includes a non-change period. FIG. 15 shows the position of the head 61 relative to the substrate ME1 in each of the passes P1 to P9. In each of the passes P1 to P9, the change period T0, the non-change period T1, and the change period T0 are sequentially shown from the start. In this example, the print regions R1 to R9 are formed so as to have the same. The non-change period T1 is a period during which the nozzle use range RN does not change as the head 61 moves during the main scan.

Also in the case shown in FIG. 15, since the number of nozzles used is reduced in the latter half of the main scanning, the “wind pattern” phenomenon that tends to occur before and after the end of the main scanning of the head 61 is suppressed before and after the end of the main scanning. Is further improved.
Of course, it is also possible to repeat the main scanning so that the change period T0 in which the nozzle use range RN increases as the head 61 moves during the main scan is included together with the non-change period T1. In this case, by reducing the number of nozzles used in the first half of the main scan, the “wind pattern” phenomenon that is likely to occur immediately after the start of the main scan of the head 61 is suppressed immediately after the start of the main scan, thereby further improving the print quality. .

  Further, during one main scan, both a change period in which the nozzle use range RN decreases as the head 61 moves and a change period in which the nozzle use range RN increases as the head 61 moves are included. Good. When the number of used nozzles decreases in the second half of the main scan, the “wind ripple” phenomenon that tends to occur before and after the end of the main scan of the head 61 is suppressed before and after the end of the main scan, and when the number of used nozzles decreases in the first half of the main scan. The “wind ripple” phenomenon that is likely to occur immediately after the start of main scanning is suppressed immediately after the start of main scanning. Accordingly, the print quality is further improved.

(8) Conclusion:
As described above, according to the present invention, it is possible to provide a technique or the like that can improve the print quality according to various aspects. Needless to say, the above-described basic functions and effects can be obtained even with the technology consisting only of the constituent elements according to the independent claims.
In addition, the configurations disclosed in the above-described examples are mutually replaced or the combination is changed, the known technology and the configurations disclosed in the above-described examples are mutually replaced or the combinations are changed. The configuration described above can also be implemented. The present invention includes these configurations and the like.

DESCRIPTION OF SYMBOLS 1 ... Printing apparatus, 2 ... Inkjet printer, 10 ... Controller, 50 ... Mechanism part, 53 ... Paper feed mechanism (example of sub-scanning part), 55 ... Main scanning part, 60 ... Carriage, 61 ... Head, 64 ... Nozzle, 67 ... ink droplets, 68 ... nozzle row, 73 ... operation panel, 74 ... output unit, 75 ... input unit, 100 ... host device, D1 ... arrangement direction, D2 ... main scanning direction, D21 ... forward direction, D22 ... reverse direction D3: Sub-scanning direction, D31: Paper feed direction, DA1: Image data, DA2: Halftone data, DT0: Dot, IM1: Print image, ME1: Substrate, P1 to P9, Pn1, Pn2 ... Pass, R1 R9, Rn1, Rn2 ... printing area, RN ... nozzle use range, T0 ... change period, T1 ... non-change period, U0 ... printing section, U1 ... control section, U2 ... selection section.

Claims (9)

A recording head having a nozzle row in which a plurality of nozzles are arranged in a direction different from the main scanning direction;
A main scanning section that repeats main scanning for moving the recording head in the main scanning direction with respect to the substrate;
A sub-scanning unit that relatively moves the recording head and the printing material in a sub-scanning direction different from the main scanning direction;
The range in which the nozzles are used in the nozzle row is set as the nozzle use range, and the main scan is repeated so that a change period in which the nozzle use range decreases or increases as the recording head moves is included during the main scan. And a control unit that performs printing.   The printing apparatus according to claim 1, wherein the control unit narrows the nozzle use range at the end of the main scan than the nozzle use range at the start of the main scan. The controller is
In forward main scanning in which the recording head moves in the forward direction in the main scanning direction, the nozzle use range at the end of the forward main scan is narrower than the nozzle use range at the start of the forward main scan. And
In the backward main scanning in which the recording head moves in the backward direction in the main scanning direction, the nozzle use range at the end of the backward main scan is narrower than the nozzle use range at the start of the backward main scan. The printing apparatus according to claim 2.   The printing apparatus according to claim 1, wherein the control unit makes the nozzle use range at the end of the main scan wider than the nozzle use range at the start of the main scan. The controller is
In forward main scanning in which the recording head moves in the forward direction in the main scanning direction, the nozzle use range at the end of the forward main scan is wider than the nozzle use range at the start of the forward main scan. And
In the backward main scanning in which the recording head moves in the backward direction in the main scanning direction, the nozzle use range at the end of the backward main scan is wider than the nozzle use range at the start of the backward main scan. The printing apparatus according to claim 4.   The printing according to any one of claims 1 to 5, wherein the main scanning unit repeats the main scanning while the recording head and the printing material are relatively moving in the sub-scanning direction. apparatus. The controller is
A first setting that repeats the main scan so that the change period is included during the main scan; and the change period in which the change period is absent or included during the repeated main scan. A selection unit that selects any one setting from a plurality of settings including a second setting in which a change in the nozzle use range is less than the first setting;
The printing apparatus according to any one of claims 1 to 6, wherein printing is performed using a nozzle in the nozzle use range according to a selected setting.   The printing apparatus according to claim 7, wherein the selection unit determines whether to select the first setting based on image data representing an image to be printed. A recording head having a nozzle row in which a plurality of nozzles are arranged in a direction different from the main scanning direction repeats the main scanning in which the recording material moves in the main scanning direction, and the sub scanning direction is different from the main scanning direction. A printing method for performing sub-scanning for relatively moving a recording head and the printing material,
The range in which the nozzles are used in the nozzle row is set as the nozzle use range, and the main scan is repeated so that a change period in which the nozzle use range decreases or increases as the recording head moves is included during the main scan. Printing method.

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