JP2007001269A - Printing system, program and printing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printing system which inhibits the generation of banding. <P>SOLUTION: The printing system comprises (A) a moving body which moves a head which delivers ink droplet toward a medium, (B) a conveying mechanism which conveys the above medium to a transfer direction, and (C) a controller which discharges the ink droplet from the head according to pixel data in which the tone of each pixel aligned in the shape of a grid is shown and dot is formed in the above medium, a dot train composed by a plurality of the above dots corresponding to a plurality of the above pixels in which positions in the transfer direction is common are formed in the above medium, and the positions of the transfer direction of the dots which compose the dot train in response to the positions of movement of the dots which compose the above dot train. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a printing system, a program, and a printing apparatus.

  In a printing apparatus such as an ink jet printer, a dot forming process that forms dots by ejecting ink droplets from a head that moves in a moving direction, and a transport that transports a medium (for example, paper, cloth, OHP paper, etc.) in the transport direction The processing is alternately repeated to print a print image composed of innumerable dots on the medium.

The image data for forming the dots is usually composed of pixel data indicating the gradation of each pixel arranged in a grid pattern. Conventionally, a print image is formed by arranging a plurality of dot rows arranged in a straight line in the movement direction in accordance with the pixels arranged in a grid pattern in the conveyance direction.
Japanese Patent Laid-Open No. 6-183033

  However, when a dot row is composed of a plurality of dots aligned in a straight line in the movement direction, a striped pattern called banding occurs in the printed image, and the image quality of the printed image may deteriorate.

  An object of the present embodiment is to suppress the occurrence of banding and improve the quality of a printed image.

  The main invention for achieving the above object includes (A) a moving body that moves a head that discharges ink droplets toward a medium in a moving direction, (B) a transport mechanism that transports the medium in the transport direction, and ( C) The ink droplets are ejected from the head in accordance with pixel data indicating the gradation of each pixel arranged in a grid pattern to form dots on the medium, corresponding to a plurality of the pixels having a common position in the transport direction. A controller for forming a dot row composed of a plurality of the dots on the medium, wherein the dots of the dots constituting the dot row according to the position in the movement direction of the dots constituting the dot row And a controller that varies the position in the transport direction.

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

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

(A) a moving body that moves a head that discharges ink droplets toward a medium in a moving direction;
(B) a transport mechanism for transporting the medium in the transport direction;
(C) forming the dots on the medium by ejecting the ink droplets from the head according to pixel data indicating the gradation of each pixel arranged in a grid pattern;
A controller that forms, on the medium, a dot row constituted by a plurality of the dots corresponding to the plurality of pixels having a common position in the transport direction;
A controller that varies the position of the dots constituting the dot row in the transport direction according to the position of the dots constituting the dot row in the movement direction;
A printing system comprising (D).
According to such a printing system, occurrence of banding can be suppressed.

  In this printing system, it is desirable that the dots have an elliptical shape having a long axis in the moving direction. In such a case, the present embodiment is particularly effective.

  In this printing system, it is preferable that the controller determines an amount of changing the position of the dots constituting the dot row in the transport direction according to the type of the medium. This is because the size of dots varies depending on the type of medium, and the likelihood of banding varies.

  Note that the controller may determine an amount of different positions in the transport direction of the dots constituting the dot row in accordance with the resolution of an image formed on the medium. In addition, the controller may determine an amount of changing the position of the dots constituting the dot row in the transport direction according to the number of nozzles forming the dot row.

  In this printing system, the transport mechanism changes the relative positional relationship of the medium with respect to the head by transporting the medium in the transport direction, and the controller controls the medium by the transport mechanism. It is desirable that the positions of the dots constituting the dot row in the transport direction are made different by changing the transport amount. Further, the controller alternately repeats a dot forming process for forming dots and a transport process for transporting the medium, and the dot forming process for forming the dots at a reference position serving as a reference in the transport direction. And the dot forming process for forming the dots at the reference position, the controller causes the transport mechanism to transport the medium with a reference transport amount serving as a reference, and the reference position In the carrying process performed between the dot forming process for forming the dot in the dot forming process and the dot forming process for forming the dot at a position shifted from the reference position, the controller determines the reference carry amount. It is preferable that the transport mechanism transports the medium with different transport amounts. Accordingly, it is possible to form the dots by shifting them in the transport direction without performing image conversion.

  In this printing system, the head has a plurality of nozzles arranged in the transport direction at predetermined intervals, and the controller ejects the ink droplets according to the position of the head in the movement direction. It is preferable to change the position of the dots constituting the dot row in the transport direction according to the position of the dots constituting the dot row in the movement direction. Even in this case, it is possible to form the dots by shifting them in the transport direction.

  In this printing system, it is preferable that the positions of the even-numbered dots constituting the dot row in the carrying direction are different from the positions of the odd-numbered dots constituting the dot row in the carrying direction. Thereby, generation | occurrence | production of banding can be suppressed.

A moving body that moves a head that discharges ink droplets toward the medium in a moving direction;
A transport mechanism for transporting the medium in the transport direction;
A printing apparatus comprising:
A function of forming dots on the medium by ejecting the ink droplets from the head according to pixel data indicating the gradation of each pixel arranged in a grid pattern;
A function of forming, on the medium, a dot row composed of a plurality of the dots corresponding to the plurality of pixels having a common position in the transport direction;
A function of changing the position of the dots constituting the dot row in the transport direction according to the position of the dots constituting the dot row in the movement direction;
A program that realizes
According to such a program, it is possible to cause the printing apparatus to print a print image in which occurrence of banding is suppressed.

(A) a moving body that moves a head that discharges ink droplets toward a medium in a moving direction;
(B) a transport mechanism for transporting the medium in the transport direction;
(C) forming the dots on the medium by ejecting the ink droplets from the head according to pixel data indicating the gradation of each pixel arranged in a grid pattern;
A controller that forms, on the medium, a dot row constituted by a plurality of the dots corresponding to the plurality of pixels having a common position in the transport direction;
A controller that varies the position of the dots constituting the dot row in the transport direction according to the position of the dots constituting the dot row in the movement direction;
A printing apparatus comprising (D).
According to such a printing apparatus, occurrence of banding can be suppressed.

=== Configuration of Printing System ===
Next, an embodiment of a printing system will be described with reference to the drawings. However, the description of the following embodiments includes embodiments relating to a computer program and a recording medium on which the computer program is recorded.

  FIG. 1 is an explanatory diagram showing an external configuration of a printing system. The printing system 100 includes a printer 1, a computer 110, a display device 120, an input device 130, and a recording / reproducing device 140. The printer 1 is a printing apparatus that prints an image on a medium such as paper, cloth, or film. The computer 110 is communicably connected to the printer 1 and outputs print data corresponding to the image to be printed to the printer 1 in order to cause the printer 1 to print an image.

  A printer driver is installed in the computer 110. The printer driver is a program for causing the display device 120 to display a user interface and converting image data output from the application program into print data. This printer driver is recorded on a recording medium (computer-readable recording medium) such as a flexible disk FD or a CD-ROM. Alternatively, the printer driver can be downloaded to the computer 110 via the Internet. This program is composed of codes for realizing various functions.

  The “printing apparatus” means an apparatus that prints an image on a medium, and corresponds to the printer 1, for example. The “printing control device” means a device that controls the printing device, for example, a computer in which a printer driver is installed. The “printing system” means a system including at least a printing apparatus and a printing control apparatus.

=== Printer driver ===
<About the printer driver>
FIG. 2 is a schematic explanatory diagram of basic processing performed by the printer driver. The components already described are given the same reference numerals, and the description thereof is omitted.

  In the computer 110, computer programs such as a video driver 112, an application program 114, and a printer driver 116 operate under an operating system installed in the computer. The video driver 112 has a function of displaying, for example, a user interface on the display device 120 in accordance with display commands from the application program 114 and the printer driver 116. The application program 114 has a function of performing image editing, for example, and creates data related to an image (image data). The user can give an instruction to print an image edited by the application program 114 via the user interface of the application program 114. Upon receiving a print instruction, the application program 114 outputs image data to the printer driver 116.

  The printer driver 116 receives image data from the application program 114, converts the image data into print data, and outputs the print data to the printer. Here, the print data is data in a format that can be interpreted by the printer 1, and is data having various command data and pixel data. Here, the command data is data for instructing the printer to execute a specific operation. The pixel data is data relating to pixels constituting an image to be printed (printed image). For example, data relating to dots formed at positions on the paper corresponding to a certain pixel (such as dot color and size). Data).

  The printer driver 116 performs resolution conversion processing, color conversion processing, halftone processing, rasterization processing, and the like in order to convert image data output from the application program 114 into print data. Hereinafter, various processes performed by the printer driver 116 will be described.

  The resolution conversion process is a process of converting image data (text data, image data, etc.) output from the application program 114 into a resolution for printing on paper. For example, when the resolution for printing an image on paper is specified as 720 × 720 dpi, the image data received from the application program 114 is converted into image data having a resolution of 720 × 720 dpi. Note that the image data after the resolution conversion process is multi-gradation (for example, 256 gradations) RGB data represented by an RGB color space. Hereinafter, RGB data obtained by performing resolution conversion processing on image data is referred to as RGB image data.

  The color conversion process is a process for converting RGB data into CMYK data represented by a CMYK color space. The CMYK data is data corresponding to the ink color of the printer. This color conversion processing is performed by the printer driver 116 referring to a table (color conversion lookup table LUT) in which gradation values of RGB image data and gradation values of CMYK image data are associated with each other. Through this color conversion process, RGB data for each pixel is converted into CMYK data corresponding to the ink color. The data after the color conversion processing is CMYK data with 256 gradations represented by the CMYK color space. Hereinafter, CMYK data obtained by performing color conversion processing on RGB image data is referred to as CMYK image data.

  The halftone process is a process for converting high gradation number data into gradation number data that can be formed by a printer. For example, data representing 256 gradations is converted into 1-bit data representing 2 gradations or 2-bit data representing 4 gradations by halftone processing. In the halftone process, pixel data is created by using a dither method, γ correction, error diffusion method, or the like so that the printer can form dots dispersedly. When performing halftone processing, the printer driver 116 refers to a dither table when performing a dither method, refers to a gamma table when performing γ correction, and refers to a diffused error when performing an error diffusion method. Refer to the error memory for storage. The data subjected to the halftone process has a resolution (for example, 720 × 720 dpi) equivalent to the RGB data described above. The halftoned data is composed of 1-bit or 2-bit data for each pixel, for example.

  The rasterizing process is a process of changing matrix (grid-like) image data in the order of data to be transferred to the printer. The rasterized data is output to the printer as pixel data included in the print data.

<About printer driver settings>
FIG. 3 is an explanatory diagram of the user interface of the printer driver. The user interface of this printer driver is displayed on the display device via the video driver 112. The user can make various settings of the printer driver using the input device 130.

  The user can select a print mode from this screen. For example, the user can select the high-speed print mode or the fine print mode as the print mode. Then, the printer driver converts the image data into print data so as to have a format corresponding to the selected print mode.

  Further, the user can select the printing resolution (dot interval when printing) from this screen. For example, the user can select 720 dpi or 360 dpi as the print resolution from this screen. Then, the printer driver performs resolution conversion processing according to the selected resolution, and converts the image data into print data.

  Further, the user can select a printing paper used for printing from this screen. For example, the user can select plain paper or glossy paper as the printing paper. If the paper type (paper type) is different, the ink bleeding and drying methods are also different, so the ink amount suitable for printing also differs. Therefore, the printer driver converts the image data into print data according to the selected paper type.

  As described above, the printer driver converts the image data into print data according to the conditions set via the user interface. The user can make various settings of the printer driver from this screen, and can also know the remaining amount of ink in the cartridge.

=== Configuration of Printer ===
<Inkjet printer configuration>
FIG. 4 is a block diagram of the overall configuration of the printer 1. FIG. 5A is a schematic diagram of the overall configuration of the printer 1. FIG. 5B is a cross-sectional view of the overall configuration of the printer 1. Hereinafter, a basic configuration of the printer will be described.

  The printer 1 of this embodiment includes a transport unit 20, a carriage unit 30, a head unit 40, a detector group 50, and a printer-side controller 60. The printer 1 that has received print data from the computer 110, which is an external device, controls each unit (conveyance unit 20, carriage unit 30, head unit 40) by the printer-side controller 60. The printer-side controller 60 controls each unit based on the print data received from the computer 110 and prints an image on paper. The situation in the printer 1 is monitored by the detector group 50, and the detector group 50 outputs the detection result to the printer-side controller 60. The printer-side controller 60 controls each unit based on the detection result output from the detector group 50.

  The transport unit 20 is for transporting a medium (for example, paper S) in a predetermined direction (hereinafter referred to as a transport direction). The transport unit 20 includes a paper feed roller 21, a transport motor 22 (also referred to as a PF motor), a transport roller 23, a platen 24, and a paper discharge roller 25. The paper feed roller 21 is a roller for feeding the paper inserted into the paper insertion slot into the printer. The transport roller 23 is a roller that transports the paper S fed by the paper feed roller 21 to a printable area, and is driven by the transport motor 22. The platen 24 supports the paper S being printed. The paper discharge roller 25 is a roller for discharging the paper S to the outside of the printer, and is provided on the downstream side in the transport direction with respect to the printable area.

  The carriage unit 30 is for moving (also referred to as “scanning”) the head in a predetermined direction (hereinafter referred to as a moving direction). The carriage unit 30 includes a carriage 31 and a carriage motor 32 (also referred to as a CR motor). The carriage 31 can reciprocate in the moving direction and is driven by a carriage motor 32. Further, the carriage 31 detachably holds an ink cartridge that stores ink.

  The head unit 40 is for ejecting ink onto paper. The head unit 40 includes a head 41 having a plurality of nozzles. Since the head 41 is provided on the carriage 31, when the carriage 31 moves in the movement direction, the head 41 also moves in the movement direction. Then, by intermittently ejecting ink while the head 41 is moving in the moving direction, dot lines (raster lines) along the moving direction are formed on the paper.

  The detector group 50 includes a linear encoder 51, a rotary encoder 52, a paper detection sensor 53, an optical sensor 54, and the like. The linear encoder 51 detects the position of the carriage 31 in the moving direction. The rotary encoder 52 detects the rotation amount of the transport roller 23. The paper detection sensor 53 detects the position of the leading edge of the paper being fed. The optical sensor 54 detects the presence or absence of paper by a light emitting unit and a light receiving unit attached to the carriage 31. The optical sensor 54 can detect the position of the edge of the paper while being moved by the carriage 31 to detect the width of the paper. The optical sensor 54 also detects the leading end (the end on the downstream side in the transport direction, also referred to as the upper end) and the rear end (the end on the upstream side in the transport direction, also referred to as the lower end) depending on the situation. it can.

  The printer-side controller 60 is a control unit (control unit) for controlling the printer. The printer-side controller 60 includes an interface unit 61, a CPU 62, a memory 63, and a unit control circuit 64. The interface unit 61 transmits and receives data between the computer 110 which is an external device and the printer 1. The CPU 62 is an arithmetic processing unit for controlling the entire printer. The memory 63 is for securing an area for storing a program of the CPU 62, a work area, and the like, and includes storage elements such as a RAM and an EEPROM. The CPU 62 controls each unit via the unit control circuit 64 in accordance with a program stored in the memory 63.

<About nozzle>
FIG. 6 is an explanatory diagram showing the arrangement of nozzles on the lower surface of the head 41. On the lower surface of the head 41, a black ink nozzle row K, a cyan ink nozzle row C, a magenta ink nozzle row M, and a yellow ink nozzle row Y are formed. Each nozzle row includes a plurality of nozzles (180 in this embodiment) that are ejection openings for ejecting ink of each color.

  The plurality of nozzles in each nozzle row are aligned at a constant interval (nozzle pitch: k · D) along the transport direction. Here, D is the minimum dot pitch in the carrying direction (that is, the interval at the highest resolution of dots formed on the paper S). K is an integer of 1 or more. For example, when the nozzle pitch is 180 dpi (1/180 inch) and the dot pitch in the transport direction is 720 dpi (1/720), k = 4.

  The nozzles in each nozzle row are assigned a lower number in the downstream nozzle (# 1 to # 180). That is, the nozzle # 1 is located downstream of the nozzle # 180 in the transport direction. Each nozzle is provided with a piezo element (not shown) as a drive element for driving each nozzle to eject ink droplets. Further, the optical sensor 54 is substantially at the same position as the nozzle # 180 on the most upstream side with respect to the position in the paper transport direction.

<About printing operation>
FIG. 7 is a flowchart of processing during printing. Each process described below is executed by the printer-side controller 60 controlling each unit in accordance with a program stored in the memory 63. This program has a code for executing each process.

  Print command reception (S001): First, the printer-side controller 60 receives a print command from the computer 110 via the interface unit 61. This print command is included in the header of print data transmitted from the computer 110. Then, the printer-side controller 60 analyzes the contents of various commands included in the received print data, and performs the following paper feed processing / conveyance processing / dot formation processing using each unit.

  Paper Feed Process (S002): The paper feed process is a process for supplying paper to be printed into the printer and positioning the paper at a print start position (also referred to as a cue position). The printer-side controller 60 rotates the paper feed roller 21 and sends the paper to be printed to the transport roller 23. Subsequently, the printer-side controller 60 rotates the transport roller 23 to position the paper fed from the paper feed roller 21 at the print start position. When the paper is positioned at the print start position, at least some of the nozzles of the head 41 are opposed to the paper.

  Dot Forming Process (S003): The dot forming process is a process for forming dots on paper by intermittently ejecting ink from a head that moves in the moving direction. The printer-side controller 60 drives the carriage motor 32 to move the carriage 31 in the movement direction. The printer-side controller 60 ejects ink from the head based on the print data while the carriage 31 is moving. When ink droplets ejected from the head 41 land on the paper, dots are formed on the paper. Since ink is intermittently ejected from the moving head 41, a dot row (raster line) composed of a plurality of dots along the moving direction is formed on the paper.

  Conveyance process (S004): The conveyance process is a process of moving the paper relative to the head in the conveyance direction. The printer-side controller 60 drives the carry motor and rotates the carry roller to carry the paper in the carrying direction. By this carrying process, the head 41 can form dots at positions different from the positions of the dots formed by the previous dot formation process.

  Paper discharge determination (S005): The printer-side controller 60 determines whether or not to discharge the paper being printed. If data to be printed remains on the paper being printed, no paper is discharged. Then, the printer-side controller 60 alternately repeats dot formation processing and conveyance processing until there is no more data to be printed, and gradually prints an image composed of dots on paper.

  Paper Discharge Process (S006): When there is no more data to be printed on the paper being printed, the printer-side controller 60 discharges the paper by rotating the paper discharge roller. The determination of whether or not to discharge paper may be based on a paper discharge command included in the print data.

  Determination of printing end (S007): Next, the printer-side controller 60 determines whether or not to continue printing. If printing is to be performed on the next paper, printing is continued and the paper feeding process for the next paper is started. If printing is not performed on the next paper, the printing operation is terminated.

Meanwhile, the printer-side controller 60 controls each unit based on the print data received from the printer driver. For example, the printer-side controller 60 causes the transport unit 20 to perform a transport process according to the transport amount indicated by the command data included in the print data. Further, the printer-side controller 60 causes the head unit to eject ink droplets in the order of the pixel data included in the print data.
For this reason, it can also be said that the printer driver that generates the print data controls the printer via the print data. In this way, it can be said that the computer 110 on which the printer driver is installed and the printer-side controller 60 control the printing operation of the entire printing system. Therefore, the computer 110 in which the printer driver is installed and the printer-side controller 60 are collectively referred to as a “controller”.

=== Basic printing operation ===
<Interlaced printing>
8A and 8B are explanatory diagrams of interlaced printing. FIG. 8A shows the position of the head (or nozzle row) and the state of dot formation in pass 1 to pass 4, and FIG. 8B shows the position of the head and the state of dot formation in pass 1 to pass 6. .

  For convenience of explanation, only one nozzle row of a plurality of nozzle rows is shown, and the number of nozzles in the nozzle row is also reduced (here, 8). The nozzles indicated by black circles in the figure are nozzles that can eject ink. On the other hand, nozzles indicated by white circles are nozzles that cannot eject ink. For convenience of explanation, the head (or nozzle row) is depicted as moving with respect to the paper, but this figure shows the relative position of the head and the paper. The paper is moved in the transport direction. Also, for convenience of explanation, each nozzle is shown as having only a few dots (circles in the figure), but in reality, ink droplets are ejected intermittently from nozzles that move in the direction of movement. Therefore, a large number of dots are arranged in the moving direction. This row of dots is also called a raster line. A dot indicated by a black circle is a dot formed in the last pass, and a dot indicated by a white circle is a dot formed in a previous pass. Note that “pass” refers to an operation (dot formation operation) in which ink is ejected from a moving nozzle to form dots. Each pass is alternately performed with an operation (conveying operation) for conveying the paper in the conveying direction.

  “Interlaced printing” means a printing method in which k is 2 or more and a raster line that is not recorded is sandwiched between raster lines that are recorded in one pass. For example, in the printing method in FIGS. 8A and 8B, three raster lines are sandwiched between raster lines formed in one pass.

  In interlace printing, each time the paper is transported in the transport direction by a constant transport amount F, each nozzle records a raster line immediately above the raster line recorded in the immediately preceding pass. In order to perform recording with a constant carry amount in this way, (1) the number N (integer) of nozzles that can eject ink is relatively prime to k, and (2) the carry amount F is N · The condition is that it is set to D.

  In the figure, the nozzle row has eight nozzles arranged along the transport direction. Since the nozzle pitch k of the nozzle array is 4, in order to satisfy the condition for performing interlaced printing, “N and k are relatively prime”, all the nozzles are not used and seven nozzles (nozzles # 1 to # 1) are used. Nozzle # 7) is used. Further, since seven nozzles are used, the paper is transported with a transport amount of 7 · D. As a result, dots are formed on the paper at a dot interval of 720 dpi (= D) using a nozzle row having a nozzle pitch of 180 dpi (4 · D). Since the actual number of nozzles (90) is greater than 7, the actual transport amount (89 · D) is greater than 7 · D.

  In the case of interlace printing, k passes are required to complete a raster line having a continuous nozzle pitch width. For example, in order to complete four raster lines that are continuous at a dot interval of 720 dpi using a nozzle row having a nozzle pitch of 180 dpi, four passes are required. According to the figure, continuous raster lines are formed at dot intervals D upstream of the raster line (raster line indicated by the arrow in the figure) formed by nozzle # 2 in pass 3 in the transport direction. It has been shown.

<Overlap printing>
9A and 9B are explanatory diagrams of overlap printing. FIG. 9A shows the head position and dot formation in pass 1 to pass 8, and FIG. 9B shows the head position and dot formation in pass 1 to pass 11.

  “Overlap printing” means a printing method in which a raster line is formed by a plurality of nozzles. For example, in the printing method in FIGS. 9A and 9B, each raster line is formed by two nozzles.

In overlap printing, each time the paper is transported at a constant transport amount F in the transport direction, each nozzle intermittently forms dots every few dots. In another pass, by forming dots so that the intermittent dots already formed by other nozzles are complemented (filling between the dots), one raster line is formed by a plurality of nozzles. It is formed. When one raster line is formed in M passes in this way, it is defined as “overlap number M”.
In FIG. 9A and FIG. 9B, since each nozzle forms dots intermittently every other dot, dots are formed in odd-numbered pixels or even-numbered pixels for each pass. Since one raster line is formed by two nozzles, the overlap number M = 2.

In overlap printing, in order to perform recording with a constant conveyance amount, (1) N / M is an integer, (2) N / M is relatively prime to k, (3) The condition is that the carry amount F is set to (N / M) · D.
9A and 9B, the nozzle row has eight nozzles arranged along the transport direction. However, since the nozzle pitch k of the nozzle row is 4, not all nozzles can be used in order to satisfy “N / M and k are relatively prime”, which is a condition for performing overlap printing. Therefore, overlap printing is performed using six of the eight nozzles. Further, since six nozzles are used, the paper is transported with a transport amount of 3 · D. As a result, for example, using a nozzle row with a nozzle pitch of 180 dpi (4 · D), dots are formed on the paper at a dot interval of 720 dpi (= D).

  When one raster line is formed by M nozzles, k × M passes are required to complete a raster line for the nozzle pitch. For example, in FIG. 9A and FIG. 9B, since one raster line is formed by two nozzles, eight passes are required to complete four raster lines. According to the figure, continuous raster lines are dots upstream of the raster line (raster line indicated by the arrow in the figure) formed by nozzle # 4 in pass 3 and nozzle # 1 in pass 7 in the transport direction. It is shown that they are formed at a distance D.

  9A and 9B, in pass 1, each nozzle forms dots on odd pixels, in pass 2, each nozzle forms dots on even pixels, and in pass 3, each nozzle forms dots on odd pixels. In 4, each nozzle forms a dot at an even pixel. That is, in the first four passes, dots are formed in the order of odd pixel-even pixel-odd pixel-even pixel. In the latter four passes (pass 5 to pass 8), dots are formed in the reverse order of the first four passes, and dots are formed in the order of even pixel-odd pixel-even pixel-odd pixel. . The dot formation order after pass 9 is the same as the dot formation order from pass 1.

=== Description of Reference Example ===
FIG. 10A is an explanatory diagram of a normally formed dot group. Here, it is assumed that dots are formed with a resolution of 720 dpi × 720 dpi. For convenience of explanation, a number is assigned to each of a plurality of dots constituting the uppermost raster line from the left.

Ink droplets are ejected from nozzles that move in the moving direction, and the ink droplets land on the paper to form dots. Therefore, the dots are elliptical with the moving direction of the carriage 31 as the major axis. In addition, there are cases where a plurality of micro ink droplets are ejected from a nozzle in a short time, and the plurality of micro ink droplets are combined to form one dot. It becomes an ellipse with the moving direction as the major axis.
When dots are formed normally, dots are formed without gaps as shown in the figure. However, since the dots are elliptical with a long axis in the movement direction, the dots adjacent in the transport direction do not overlap much compared to the dots adjacent in the movement direction.

FIG. 10B is an explanatory diagram when the dots become smaller. Here, the description will be given focusing on two raster lines.
One of the causes of dot reduction is the effect of paper. Glossy paper having an ink absorbing layer on the surface has higher ink absorbability than plain paper, so ink droplets that have landed on the paper are likely to penetrate without bleeding. For this reason, the dots formed on glossy paper are smaller than those on plain paper.
Another cause of dot reduction is head manufacturing error. For example, the ink amount of ink droplets ejected from the nozzle may be reduced due to the influence of the processing accuracy of the nozzle opening. When the ink amount of the ejected ink droplet is small and the size of the ink droplet is small, the dots formed by the ink droplet are also small.
When the dots become smaller, as shown in the figure, the dots adjacent in the transport direction are separated from each other, and a gap is generated. Further, when a raster line is formed by small dots, as shown in the figure, the gap extends in the moving direction, and a light white stripe is formed in the printed image. This white streak is called “banding” and causes deterioration in the image quality of the printed image.

  FIG. 10C is an explanatory diagram when the dots are formed so as to be shifted in the transport direction.

As one of the causes of the dot formation being shifted, a head manufacturing error can be considered. For example, an abnormality occurs in the flying direction of the ink droplet ejected from the nozzle due to the influence of the processing accuracy of the opening of the nozzle. As a result, the landing positions of the ink droplets are shifted and dots are formed shifted.
In addition, as one of the other causes of dot formation, the influence of head vibration and head tilt can be considered. If the head vibrates or the head itself is tilted, the transport direction component may be included in the flying direction of the ink droplets. Even in this state, as long as the distance between the nozzle and the paper is the same for all nozzles, all dots are formed in the same way in the transport direction. Is not formed. However, if the distance between the nozzle and the paper is different for each nozzle in the state where the ink droplet flying direction includes the conveyance direction component, the deviation in the dot conveyance direction differs depending on this distance.

  When dots are formed shifted in the transport direction, dots adjacent in the transport direction are separated from each other as shown in the figure, and a gap is generated. Further, when a raster line is formed by dots shifted in the transport direction, the gap extends in the movement direction as shown in the figure, and a light white stripe is formed in the printed image. This white streak also causes image quality degradation as “banding”.

  In this embodiment, dots are formed so as to make such banding inconspicuous, thereby improving the image quality of the printed image. However, in the present embodiment, it is possible to suppress not only the banding caused by the above cause but also the occurrence of banding caused by other causes.

=== Dot Arrangement of the Present Embodiment ===
FIG. 11A is an explanatory diagram of the dot arrangement of this embodiment. In this figure, for the purpose of explanation, dots are normally formed with a resolution of 720 dpi × 720 dpi. For convenience of explanation, a number is assigned to each of a plurality of dots constituting the uppermost raster line from the left.

  In the present embodiment, the odd-numbered dots are formed at the same positions as in FIG. 10A described above. However, the even-numbered dots in this embodiment are formed with a shift of 1/2880 inches in the transport direction as compared with the case of FIG. 10A described above. In the other raster lines, although the numbers are not shown, even-numbered dots are formed with a shift of 1/2880 inch in the transport direction as compared with the case of FIG. Has been.

FIG. 11B is an explanatory diagram in the case where the dots become smaller in the dot arrangement of the present embodiment.
When the dots become smaller, also in this embodiment, as in the above-described reference example (FIG. 10B), the dots adjacent in the transport direction are separated from each other, and a gap is generated. However, in the present embodiment, the position of the even-numbered dots in the transport direction is shifted by 1/2880 inches from the position of the odd-numbered dots in the transport direction, so the position of the gap between the even-numbered dots However, it is shifted by about 1/2880 inch in the transport direction with respect to the position of the gap between the odd-numbered dots. For this reason, as in the above-described reference example, the gap is less likely to be connected in the moving direction, and the banding is less visible.

FIG. 11C is an explanatory diagram in the case where dots are further shifted in the transport direction in the dot arrangement of this embodiment.
If the dots are displaced in the carrying direction, also in the present embodiment, as in the above-described reference example (FIG. 10C), the dots adjacent in the carrying direction are separated from each other, and a gap is generated. However, in the present embodiment, the position of the even-numbered dots in the transport direction is shifted by 1/2880 inch from the position of the odd-numbered dots in the transport direction, so the position of the gap between the even-numbered dots However, it is shifted by about 1/2880 inch in the transport direction with respect to the position of the gap between the odd-numbered dots. For this reason, as in the above-described reference example, the gap is less likely to be connected in the moving direction, and the banding is less visible.

Thus, in the present embodiment, the occurrence of banding is suppressed by changing the position in the transport direction of the dots constituting the raster line according to the position in the movement direction.

=== Relationship between Pixels and Dots of this Embodiment ===
FIG. 12 is an explanatory diagram of processing of the printer driver in the present embodiment.
The squares in the upper left diagram in the figure are explanatory diagrams of image data after color conversion processing performed after resolution conversion. Here, only K data (black data) of the image data (CMYK data) will be described for explanation.
The K data of the image data after the color conversion process is composed of a plurality of pixel data. Each pixel data is data indicating the black gradation value (256 gradations) of the corresponding pixel. As shown in the upper left diagram in the figure, the pixels are arranged in a grid along the X direction (corresponding to the movement direction) and the Y direction (corresponding to the transport direction).

  Looking at the dot arrangement of FIG. 11A, in this embodiment, it may seem as if the pixel arrangement of the upper left figure of FIG. . However, in the present embodiment, such image conversion is not performed. In the present embodiment, the printer driver performs halftone processing and rasterization processing on the image data having the pixel arrangement at the upper left in FIG. That is, the printer driver only performs normal halftone processing and rasterization processing.

  However, in the present embodiment, even if image conversion is not performed, according to the plurality of pixels (the plurality of pixels having the same position in the Y direction) indicated by thick lines in the upper left diagram in FIG. 12, the lower left diagram in FIG. As shown by the thick line, a raster line in which dots shifted by 1/2880 inches in the carrying direction are alternately arranged along the moving direction is formed. That is, in the present embodiment, even if the pixel data is the same pixel in the Y direction (conveyance direction), the raster line is configured according to the position in the X direction (movement direction) of the dots forming the raster line. The position of the dot in the Y direction (conveyance direction) will change.

=== Printing Operation of this Embodiment ===
FIG. 13 is an explanatory diagram of the printing operation of the present embodiment. FIG. 14 is an explanatory diagram of how dots are formed in the area indicated by the dotted line in FIG. On the left side of FIG. 14, the nozzles indicated by hatching are the nozzles that form even-numbered dots. In addition, on the right side of FIG. 14, dots indicated by hatching are even-numbered dots.

  Compared with the printing method of FIG. 9A described above, the printing method of the present embodiment differs in the conveyance amount in the conveyance process performed between passes. In the printing method of FIG. 9A, the transport amount F is constant, whereas in the printing method of the present embodiment, the adjustment value C is added to or subtracted from the transport amount F according to the pass.

  The adjustment value C is 1/2880 inch. As will be described later, the adjustment value C is set according to the type of paper to be printed. In the present embodiment, since the adjustment value C is 1/2880 inch, the position in the transport direction of the even-numbered dots is shifted by 1/2880 inches from the position in the transport direction of the odd-numbered dots.

  In the case where odd-numbered dots are formed in a certain pass and even-numbered dots are formed in the next pass, in the transport processing performed between these passes, the transport amount is set to the normal transport amount F with an adjustment value C. It becomes the addition. As a result, even-numbered dots are formed at positions upstream in the transport direction by 1/2880 inches with respect to positions in the transport direction of odd-numbered dots. For example, in the transport process performed between pass 1 and pass 2, the transport process performed between pass 3 and pass 4, the transport process performed between pass 6 and pass 7, and the like, However, the adjustment value C is larger than the normal transport amount F.

  In the case where even-numbered dots are formed in a certain pass and odd-numbered dots are formed in the next pass, the transport amount is adjusted to the normal transport amount F in the transport process performed between these passes. Subtract C. As a result, odd-numbered dots are formed at positions downstream of the conveyance direction by 1/2880 inches with respect to the positions of the even-numbered dots in the conveyance direction. For example, in the transport process performed between pass 2 and pass 3, the transport process performed between pass 5 and pass 6, the transport process performed between pass 7 and pass 8, and the like, However, the adjustment value C is smaller than the normal transport amount F.

  When even-numbered dots are formed in a certain pass and even-numbered dots are formed in the next pass, the transport amount of the transport process performed between these passes is a normal transport amount F. For example, in the conveyance process performed between the pass 4 and the pass 5, the conveyance amount is the normal conveyance amount F. Similarly, when odd-numbered dots are formed in a certain pass and odd-numbered dots are formed in the next pass, the transport amount of the transport process performed between these passes is a normal transport amount F. For example, although not shown, in the conveyance process performed between pass 8 and pass 9, the conveyance amount becomes the normal conveyance amount F.

=== Setting of Adjustment Value C ===
As already described, the size of the dot changes depending on the paper type. Since the gap between the dots changes according to the size of the dots, the occurrence of banding and the ease of visual recognition differ depending on the paper type. On the other hand, if banding is unlikely to occur, the adjustment value C may be small. If banding is likely to occur, increasing the adjustment value C makes it difficult to visually recognize the banding. Therefore, in this embodiment, since the paper type is selected by the setting of the printer driver (see FIG. 3), the adjustment value C is determined according to the selected paper type.

FIG. 15 is an explanatory diagram of a table showing the relationship between the paper type and the adjustment value C. In this table, the paper type and the adjustment value C are associated with each other.
Since glossy paper has an ink absorbing layer on its surface, the dots formed on the glossy paper have a clearer shape (contour) than plain paper. For this reason, glossy paper is easier to recognize banding than plain paper. Therefore, the adjustment value C for glossy paper is larger than the adjustment value for plain paper. Also, printing on plain paper does not require higher image quality than glossy paper. Also, since printing is performed at a lower resolution than glossy paper, the dots used are large and banding is difficult to recognize. In such a case, the adjustment value is set to zero.

  As described above, the adjustment values in the table are values corresponding to the required image quality, the shape of dots formed on the paper, and the banding.

  The printer driver has such a table in advance. Then, at the time of printing, the printer driver acquires information on the paper type selected by the printer driver setting, refers to the table based on this paper type, and determines an adjustment value C corresponding to the paper type.

FIG. 16 is an explanatory diagram of another table. In this table, the resolution, the number of overlaps, and the adjustment value are associated with each other.
When the resolution is low, for example, a resolution of 360 × 360 dpi is often applied when the user does not require high image quality, such as plain paper. As described above, banding is difficult to recognize because the dot used is large when the resolution is low. Therefore, in such a case, the adjustment value is set to zero. On the other hand, when the overlap number M is high, the number of nozzles forming one raster line increases. In such a case, it is considered that banding is unlikely to occur, so the adjustment value C is a low value.

  The printer is provided with such a table in advance. At the time of printing, the printer driver acquires information such as the resolution selected by the setting of the printer driver, refers to the table based on the information such as the resolution, and determines the corresponding adjustment value C.

  Thus, the determination of the adjustment value C is not limited to that determined according to the paper type. However, in this embodiment, the adjustment value C determined according to the paper type is preferentially adopted.

=== Other Embodiments ===
The above-described embodiment is mainly described for a printer. Among them, a printing apparatus, a recording apparatus, a liquid ejection apparatus, a printing method, a recording method, a liquid ejection method, a printing system, a recording system, and a computer system are included. Needless to say, the disclosure includes a program, a storage medium storing the program, a display screen, a screen display method, a printed material manufacturing method, and the like.

  Moreover, although the printer etc. as one embodiment were demonstrated, said embodiment is for making an understanding of this invention easy, and is not for limiting and interpreting this invention. The present invention can be changed and improved without departing from the gist thereof, and it is needless to say that the present invention includes equivalents thereof. In particular, the embodiments described below are also included in the present invention.

<About nozzle row>
In the above-described embodiment, the nozzle pitch of the nozzle row was 1/180 inch. However, it is not limited to this. If the nozzle pitch is 1/2880 inches, dots can be formed as follows.
FIG. 17 is an explanatory diagram of dot formation using a nozzle row having a nozzle pitch of 1/2880 inches.
In this embodiment, the nozzle for ejecting ink droplets changes according to the position of the head in the moving direction. For example, when dots are formed on odd-numbered pixels, every fourth nozzle of nozzle # 1, nozzle # 5, nozzle # 9,... Ejects ink droplets, and dots are formed on even-numbered pixels. When doing so, every fourth nozzle of nozzle # 2, nozzle # 6, nozzle # 10,... Ejects ink droplets. Thereby, it is possible to form dots with the same dot arrangement as in the above-described embodiment in one pass.
However, in this embodiment, the amount of shifting the dot depends on the nozzle pitch. On the other hand, in the above-described embodiment, the amount of shifting the dots can be adjusted by the carry amount, so that it does not depend on the nozzle pitch.
The nozzle pitch may be composed of a plurality of nozzle rows.

<About nozzle>
In the above-described embodiment, ink is ejected using a piezoelectric element. However, the method for discharging the liquid is not limited to this. For example, other methods such as a method of generating bubbles in the nozzle by heat may be used.

=== Summary ===
(1) The printing system described above includes the printer 1 and the computer 110. This printing system includes a carriage 31 (an example of a moving body), a conveyance unit 20 (an example of a conveyance mechanism), and a controller (a computer on which a printer driver is installed and a printer-side controller).

  The carriage 31 moves the head 41 that ejects ink droplets toward a medium (for example, paper, cloth, OHP paper, etc.) in the movement direction. The transport unit 20 transports the medium in the transport direction. In addition, the controller forms dots on the medium by ejecting ink droplets from the head 41 in accordance with pixel data indicating the gradation of each pixel arranged in a grid. Then, the controller forms a raster line (dot row) on the medium with a plurality of dots corresponding to a plurality of pixels (see the upper left in FIG. 12) whose positions in the transport direction are common.

  Normally, raster lines formed based on a plurality of pixels having common positions in the transport direction (see the upper left in FIG. 12) are arranged in series along the movement direction (positions in the transport direction are the same as shown in FIG. 10A). To be formed). However, in the case of such a dot arrangement, banding is likely to occur when the dots become smaller or when the dots are formed out of alignment (see FIGS. 10B and 10C).

  Therefore, in the present embodiment, the positions of the dots constituting the raster line in the transport direction are made different according to the positions of the dots constituting the raster line in the moving direction. For example, the position of the even-numbered dots in the transport direction is shifted by 1/2880 inch upstream of the position of the odd-numbered dots in the transport direction (FIG. 11A, the lower left diagram in FIG. 12, the right diagram in FIG. 14). reference). Accordingly, in the present embodiment, banding is less noticeable when the dots become smaller or when the dots are formed out of alignment (see FIGS. 11B and 11C).

  Further, in this embodiment, image conversion in accordance with such dot arrangement is not performed, and the position in the transport direction differs depending on the position in the movement direction based on the pixel data of pixels aligned in a straight line along the movement direction. A raster line composed of such dots is formed (see FIG. 12). For this reason, the amount of calculation can be reduced.

(2) When ink droplets are ejected from the head 41 that moves in the moving direction, the dots formed thereby become elliptical with the moving direction as the major axis. Thus, in the case of an ellipse having a major axis in the moving direction, the banding is less noticeable when the dot becomes smaller or when the dot is formed out of alignment. For this reason, this embodiment is particularly effective in the case of such a dot shape.

(3) In the above-described embodiment, the controller changes the adjustment value C (the amount by which the position in the transport direction of the dots constituting the raster line varies) according to the paper type (paper type) (FIG. 15). This is because the size of dots formed on the medium changes depending on the paper type, and the likelihood of banding varies. For this reason, banding is less likely to occur in plain paper with a large dot size, so the adjustment value C is smaller than that in glossy paper with a small dot size (see FIG. 15).
In order to suppress banding, a larger adjustment value C is desirable. However, if the adjustment value C is too large, the deviation of the dot arrangement with respect to the image data becomes large and the image quality deteriorates. For this reason, the adjustment value C is desirably set to a minimum amount.

(4) In the above-described embodiment, the controller changes the adjustment value C according to the resolution of the print image. For example, when the resolution is low, it is considered that the user does not request high image quality. In such a case, the adjustment value may be lowered.

(5) In the above-described embodiment, the controller changes the adjustment value C according to the overlap number M (the number of nozzles forming a raster line). When the number of overlaps is high, the number of nozzles forming one raster line increases, and it is considered that banding is unlikely to occur, so the adjustment value C can be set to a low value.

(6) According to the above-described embodiment, the controller changes the position of the dots constituting the raster line in the transport direction by changing the transport amount of the medium by the transport unit 20 (see FIGS. 13 and 14). ). Thus, a raster line composed of dots whose positions in the transport direction are different depending on the position in the movement direction based on the pixel data of the pixels aligned in a straight line along the movement direction without performing special image conversion. Can be formed (see FIG. 12).

(7) When the position in the transport direction of the dots (dots formed with odd pixels) indicated by white circles in the right diagram of FIG. 14 is the reference position, a path for forming dots at the reference position and the reference position In the transport process performed between the dots and the pass for forming dots, the controller transports the medium by the transport unit 20 with the transport amount F serving as a reference. For example, although not shown, in the conveyance process performed between pass 8 and pass 9, the conveyance amount becomes the normal conveyance amount F. On the other hand, in a transport process performed between a pass for forming dots at the reference position and a pass for forming dots at positions shifted from the reference position, the controller uses a transport amount F + C different from the reference transport amount F. The medium is transported to the transport mechanism. For example, in the transport process performed between pass 1 and pass 2, the transport process performed between pass 3 and pass 4, the transport process performed between pass 6 and pass 7, and the like, However, the adjustment value C is larger than the normal transport amount F.
Thus, a raster line composed of dots whose positions in the transport direction are different depending on the position in the movement direction based on the pixel data of the pixels aligned in a straight line along the movement direction without performing special image conversion. Can be formed (see FIG. 12).

(8) It should be noted that the method of shifting the dots is not limited to the method of changing the carry amount.
For example, if the head 41 has 1/2880 inch intervals, the controller changes the nozzles used in accordance with the position of the head in the moving direction, thereby moving the positions of the dots constituting the raster line in the moving direction. Accordingly, the position of the dots constituting the raster line in the transport direction can be shifted (see FIG. 17).
However, in the case of such a printing method, since the amount of shifting the dot depends on the nozzle pitch, the dot cannot be shifted by an arbitrary amount.

(9) In the above-described embodiment, the dots are shifted every two. For this reason, in the above-described embodiment, the positions in the transport direction of the even-numbered dots constituting the raster line are shifted from the positions in the transport direction of the odd-numbered dots constituting the raster line.
However, the present invention is not limited to this. For example, the dots may be shifted as shown in FIG. Even if it does in this way, the effect which suppresses generation | occurrence | production of banding is acquired.
However, in this case, the amount when the dots are displaced the most is 2/2880 inches, and the amount of deviation increases. For this reason, the deviation of the dot arrangement with respect to the image data becomes large, and the image quality may be deteriorated.

(10) If all the configurations of the above-described embodiment are provided, all the effects can be achieved, which is desirable. However, it is needless to say that not all configurations are necessary.

(11) The above-described printer driver (an example of a program) generates print data, and transmits the print data to a printer (an example of a printing apparatus), thereby controlling the printer via the print data.
The printer controls each unit based on the print data, thereby ejecting ink droplets from the head in accordance with pixel data indicating the gradation of pixels arranged in a grid pattern to form dots on the medium. Further, the printer forms a raster line (dot row) on the medium with a plurality of dots corresponding to a plurality of pixels (see the upper left in FIG. 12) having a common position in the transport direction based on the print data. Also, the printer varies the positions of the dots constituting the raster line in the transport direction according to the positions of the dots constituting the raster line in the moving direction based on the print data.

Such a printer driver can cause the printing apparatus to print a high-quality print image in which banding is difficult to visually recognize.

(12) The printer itself may have the printer driver function described above.

It is explanatory drawing of the whole structure of a printing system. FIG. 10 is an explanatory diagram of processing performed by a printer driver. 3 is an explanatory diagram of a user interface of a printer driver. FIG. 1 is a block diagram of an overall configuration of a printer 1. FIG. FIG. 5A is a schematic diagram of the overall configuration of the printer 1. FIG. 5B is a cross-sectional view of the overall configuration of the printer 1. It is explanatory drawing which shows the arrangement | sequence of a nozzle. It is a flowchart of the process at the time of printing. 8A and 8B are explanatory diagrams of interlaced printing. 9A and 9B are explanatory diagrams of overlap printing. FIG. 10A is an explanatory diagram of a dot group normally formed in the reference example. FIG. 10B is an explanatory diagram when the dots are reduced in the reference example. FIG. 10C is an explanatory diagram in the case where dots are formed so as to be shifted in the transport direction in the reference example. FIG. 11A is an explanatory diagram of the dot arrangement of this embodiment. FIG. 11B is an explanatory diagram in the case where the dots become smaller in the dot arrangement of the present embodiment. FIG. 11C is an explanatory diagram in the case where dots are further shifted in the transport direction in the dot arrangement of this embodiment. FIG. 8 is an explanatory diagram of processing of a printer driver in the present embodiment. It is explanatory drawing of the printing operation of this embodiment. It is explanatory drawing of the mode of formation of the dot of the area | region shown with a dotted line in FIG. It is explanatory drawing of the table which shows the relationship between the paper type and adjustment value C. It is explanatory drawing of another table. It is explanatory drawing of another embodiment. It is explanatory drawing of another dot arrangement | positioning.

Explanation of symbols

1 printer,
20 transport unit, 21 paper feed roller, 22 transport motor (PF motor),
23 transport roller, 24 platen, 25 discharge roller,
30 Carriage unit, 31 Carriage,
32 Carriage motor (CR motor),
40 head units, 41 heads,
50 detector groups, 51 linear encoder, 52 rotary encoder,
53 Paper detection sensor, 54 Optical sensor,
60 Printer-side controller, 61 Interface section,
62 CPU, 63 memory, 64 unit control circuit 100 printing system, 110 computer,
112 video drivers, 114 application programs,
116 printer driver, 120 display device,
130 input device, 140 recording / reproducing device

Claims (12)

(A) a moving body that moves a head that discharges ink droplets toward a medium in a moving direction;
(B) a transport mechanism for transporting the medium in the transport direction;
(C) forming the dots on the medium by ejecting the ink droplets from the head according to pixel data indicating the gradation of each pixel arranged in a grid pattern;
A controller that forms, on the medium, a dot row constituted by a plurality of the dots corresponding to the plurality of pixels having a common position in the transport direction;
A controller that varies the position of the dots constituting the dot row in the transport direction according to the position of the dots constituting the dot row in the movement direction;
A printing system comprising (D). The printing system according to claim 1,
The printing system according to claim 1, wherein the dot has an elliptical shape having a major axis in the moving direction. The printing system according to claim 1 or 2,
The printing system according to claim 1, wherein the controller determines an amount by which the position of the dots constituting the dot row in the transport direction varies according to the type of the medium. The printing system according to any one of claims 1 to 3,
The printing system according to claim 1, wherein the controller determines an amount of changing the position of the dots constituting the dot row in the transport direction according to a resolution of an image formed on the medium. The printing system according to any one of claims 1 to 4,
The printing system according to claim 1, wherein the controller determines an amount of changing the position of the dots constituting the dot row in the transport direction according to the number of nozzles forming the dot row. A printing system according to any one of claims 1 to 5,
The transport mechanism changes the relative positional relationship of the medium with respect to the head by transporting the medium in the transport direction.
The printing system, wherein the controller varies the position of the dots constituting the dot row in the transport direction by changing the transport amount of the medium by the transport mechanism. The printing system according to claim 6, wherein
The controller repeats alternately a dot formation process for forming dots and a conveyance process for conveying the medium,
In the transport process performed between the dot formation process for forming the dot at a reference position serving as a reference in the transport direction and the dot formation process for forming the dot at the reference position, the controller The medium is transported to the transport mechanism with a reference transport amount of
In the transport process performed between the dot formation process for forming the dot at the reference position and the dot formation process for forming the dot at a position shifted from the reference position, the controller performs the reference transport. A printing system, wherein the medium is conveyed by the conveyance mechanism with a conveyance amount different from the amount. A printing system according to any one of claims 1 to 5,
The head has a plurality of nozzles arranged in the transport direction at predetermined intervals,
The controller changes the nozzles that eject the ink droplets according to the position of the head in the movement direction, thereby changing the dot lines according to the positions of the dots constituting the dot line in the movement direction. A printing system, wherein the positions of the dots in the transport direction are made different. A printing system according to any one of claims 1 to 8,
The printing system is characterized in that the positions of the even-numbered dots constituting the dot row in the carrying direction are different from the positions of the odd-numbered dots constituting the dot row in the carrying direction. (A) a moving body that moves a head that discharges ink droplets toward a medium in a moving direction;
(B) a transport mechanism for transporting the medium in the transport direction;
(C) forming the dots on the medium by ejecting the ink droplets from the head according to pixel data indicating the gradation of each pixel arranged in a grid pattern;
A controller that forms, on the medium, a dot row constituted by a plurality of the dots corresponding to the plurality of pixels having a common position in the transport direction;
A controller that varies the position of the dots constituting the dot row in the transport direction according to the position of the dots constituting the dot row in the movement direction;
A printing system comprising (D),
(E) The dot has an elliptical shape having a major axis in the movement direction,
(F) The controller determines an amount to vary the position in the transport direction of the dots constituting the dot row according to the type of the medium,
(G) The transport mechanism changes the relative positional relationship of the medium with respect to the head by transporting the medium in the transport direction.
The controller varies the position in the transport direction of the dots constituting the dot row by changing the transport amount of the medium by the transport mechanism,
(H) The controller alternately repeats a dot formation process for forming dots and a conveyance process for conveying the medium.
In the transport process performed between the dot formation process for forming the dot at a reference position serving as a reference in the transport direction and the dot formation process for forming the dot at the reference position, the controller The medium is transported to the transport mechanism with a reference transport amount of
In the transport process performed between the dot formation process for forming the dot at the reference position and the dot formation process for forming the dot at a position shifted from the reference position, the controller performs the reference transport. Causing the transport mechanism to transport the medium with a transport amount different from the amount,
(I) The printing system is characterized in that the positions of the even-numbered dots constituting the dot row in the carrying direction are different from the positions of the odd-numbered dots constituting the dot row in the carrying direction. A moving body that moves a head that discharges ink droplets toward the medium in a moving direction;
A transport mechanism for transporting the medium in the transport direction;
A printing apparatus comprising:
A function of forming dots on the medium by ejecting the ink droplets from the head according to pixel data indicating the gradation of each pixel arranged in a grid pattern;
A function of forming, on the medium, a dot row composed of a plurality of the dots corresponding to the plurality of pixels having a common position in the transport direction;
A function of changing the position of the dots constituting the dot row in the transport direction according to the position of the dots constituting the dot row in the movement direction;
A program that realizes (A) a moving body that moves a head that discharges ink droplets toward a medium in a moving direction;
(B) a transport mechanism for transporting the medium in the transport direction;
(C) forming the dots on the medium by ejecting the ink droplets from the head according to pixel data indicating the gradation of each pixel arranged in a grid pattern;
A controller that forms, on the medium, a dot row constituted by a plurality of the dots corresponding to the plurality of pixels having a common position in the transport direction;
A controller that varies the position of the dots constituting the dot row in the transport direction according to the position of the dots constituting the dot row in the movement direction;
A printing apparatus comprising (D).

Images