JP2005132008A - Printer, printing control device, printing method and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the quality of the whole printing image by bringing the quality of printing image by first printing processing close to that of second printing processing. <P>SOLUTION: A printer comprises a transfer unit which transfers a medium to transfer direction and a movable body which moves a plurality of nozzles arranged in the transfer direction to movement direction. The printer performs first printing processing to repeat transfer operation in which the transfer unit transfers the medium in a predetermined transfer quantity and dot-forming operation in which a plurality of dot rows are formed on the medium by discharging an ink from the plurality of moving nozzles, and second printing processing to repeat transfer operation in which the transfer unit transfers the medium in a transfer quantity different from the predetermined transfer quantity and dot-forming operation in which a plurality of dot rows are formed on the medium by discharging an ink from the plurality of moving nozzles. In the first printing processing and the second printing processing of the printer, between the dot rows formed from one of the dot-forming operation, are inserted a plurality of the dot rows formed from other dot-forming operations. The order of formation of the plurality of inserted dot rows in the first printing processing is the same as the order of formation in the second printing processing. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

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

  A printing apparatus including a conveyance unit that conveys a medium (for example, paper, cloth, an OHP sheet) in the conveyance direction, and a moving body (for example, a carriage) that moves a plurality of nozzles arranged in the conveyance direction in the movement direction. (For example, printers, particularly ink jet printers) are known.

Among such printing apparatuses, one that prints on a medium by a first printing process and a second printing process is known. Here, the first printing process includes a transport operation in which the transport unit transports the medium by a predetermined transport amount, and a dot formation operation in which ink is ejected from a plurality of moving nozzles to form a plurality of dot rows on the medium. And the process of repeating. The second printing process includes a transport operation in which the transport unit transports the medium with a transport amount different from the transport amount of the first print process, and a plurality of dot rows by ejecting ink from the plurality of moving nozzles. Is a process of repeating the dot forming operation for forming the image on the medium.
JP 2000-343688 A

As described above, when the print image is formed on the medium by the first print process and the second print process, the print image includes an area printed by the first print process and an area printed by the second print process. Exists.
However, if the print quality of the first print process is different from that of the second print process, the difference in image quality between the two areas is noticeable, and the image quality of the entire print image is deteriorated.
Accordingly, an object of the present invention is to improve the image quality of the entire print image by bringing the image quality of the print image by the first print processing and the second print processing close to the same quality.

In the main invention for achieving the above object, in the first printing process and the second printing process, a dot row formed by another dot forming operation between the dot rows formed by one dot forming operation. Is formed, and the formation order in the first printing process of the plurality of dot rows thus sandwiched is equal to the formation order in the second printing process.
Other features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

  According to the present invention, the image quality of the print image obtained by the first print process and the second print process can be brought close to each other, and the image quality of the entire print image can be improved.

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

A transport unit for transporting the medium in the transport direction;
A moving body that moves a plurality of nozzles arranged in the transport direction in the movement direction;
With
A first operation of repeating a transport operation in which the transport unit transports the medium by a predetermined transport amount and a dot forming operation in which ink is ejected from the plurality of moving nozzles to form a plurality of dot rows on the medium. Printing process,
A transport operation in which the transport unit transports the medium with a transport amount different from the predetermined transport amount, and a dot forming operation in which ink is ejected from the plurality of moving nozzles to form a plurality of dot rows on the medium. And a second printing process that repeats
A printing device for performing
In the first printing process and the second printing process, a plurality of dot rows formed by other dot forming operations are sandwiched between the dot rows formed by one dot forming operation. ,
The printing apparatus, wherein a formation order of the plurality of the dot rows sandwiched between the first print processes is equal to the formation order of the second print processes.
According to such a printing apparatus, it is possible to improve the image quality of the entire print image by bringing the image quality of the print image by the first print processing and the second print processing close to the same quality.

  In such a printing apparatus, it is desirable to form dots on pixels that are continuous in the moving direction by one dot forming operation. Accordingly, the printing apparatus can perform high-speed printing while improving the image quality of the entire print image.

  In this printing apparatus, the interval in the transport direction of dots formed on the medium is D, the interval in the transport direction of the nozzles that eject the ink is k · D, and the ink in the first printing process is ejected. Where N1 is the number of nozzles and the number of nozzles ejecting the ink in the second printing process is N2, N1 and k are in a prime relationship with each other, and N2 and k are in a prime relationship with each other, It is desirable that the remainder when N1 is divided by k is equal to the remainder when N2 is divided by k. If this condition is satisfied, the image quality of the entire printed image can be improved. Further, k is preferably in a prime relationship with a natural number smaller than k other than 1 or k-1. Thereby, remarkable deterioration of the printed image can be suppressed. The remainder is preferably other than 1 or k-1. Thereby, ink bleeding can be suppressed. Further, it is preferable that the dot row is formed by the next dot forming operation without being adjacent to the dot row formed by the previous dot forming operation. Thereby, ink bleeding can be suppressed.

  In such a printing apparatus, it is preferable that dots are formed in pixels that are continuous in the moving direction by a plurality of dot forming operations. Thereby, the printing apparatus can suppress the deterioration of the image quality due to the manufacturing error of the nozzles, and can improve the image quality of the entire printed image.

  In this printing apparatus, the interval between the dots formed on the medium in the transport direction is D, the interval between the nozzles for ejecting the ink is k · D, and dots are continuously formed in the pixels in the movement direction. The number of dot forming operations until formation is M, the number of nozzles ejecting the ink in the first printing process is N1, and the number of nozzles ejecting the ink in the second printing process is N2. When N1 / M and k are in a prime relationship, N2 / M and k are in a prime relationship, and when N1 / M is divided by k, the remainder when N2 / M is divided by k It is desirable to be equal to the remainder of. If this condition is satisfied, the image quality of the entire printed image can be improved. Further, it is preferable that k is in a prime relationship with a natural number smaller than k other than 1 or k-1. Thereby, remarkable deterioration of the printed image can be suppressed. The remainder is preferably other than 1 or k. Thereby, ink bleeding can be suppressed. Further, it is preferable that the dot row is formed by the next dot forming operation without being adjacent to the dot row formed by the previous dot forming operation. Thereby, ink bleeding can be suppressed.

  Further, in such a printing apparatus, in one dot forming operation, a position of a dot formed by a nozzle in the moving direction is different from a position of a dot formed by another nozzle in the moving direction. It is desirable that it is possible. In addition, it is preferable that the dot formation order of the plurality of dot rows sandwiched between is the same in all regions where dots are formed by the first printing process. Thereby, dots can be formed in the same dot formation order in the area printed by the first printing process. In addition, it is preferable that the dot formation order in the first printing process is equal to the dot formation order in the second printing process. Thereby, the dot formation order in the area | region where a dot is formed by the 1st printing process and the 2nd printing process can be made to correspond.

  In the printing apparatus, it is preferable that borderless printing is performed on the medium by the first printing process and the second printing process. In borderless printing, the transport amount changes during printing, but the printed image can be of high quality.

A transport unit for transporting the medium in the transport direction;
A moving body that moves a plurality of nozzles arranged in the transport direction in the movement direction;
In a printing device equipped with
A first operation of repeating a transport operation in which the transport unit transports the medium by a predetermined transport amount and a dot forming operation in which ink is ejected from the plurality of moving nozzles to form a plurality of dot rows on the medium. Printing process,
A transport operation in which the transport unit transports the medium with a transport amount different from the predetermined transport amount, and a dot forming operation in which ink is ejected from the plurality of moving nozzles to form a plurality of dot rows on the medium. And a second printing process that repeats
A printing control device for performing
In the first printing process and the second printing process, a plurality of dot rows formed by other dot forming operations are sandwiched between the dot rows formed by one dot forming operation. ,
The printing control apparatus according to claim 1, wherein a forming order of the plurality of dot rows sandwiched between the first printing processes is equal to the forming order of the second printing processes.
According to such a print control apparatus, the image quality of the print image by the first print process and the second print process can be brought close to the same quality, and the image quality of the entire print image can be improved.

A first operation that repeats a transport operation for transporting a medium in a transport direction by a predetermined transport amount and a dot formation operation for ejecting ink from a plurality of nozzles moving in the movement direction to form a plurality of dot rows on the medium. Printing process,
A transport operation for transporting the medium in the transport direction by a transport amount different from the predetermined transport amount, and a plurality of dot rows are formed on the medium by ejecting ink from the plurality of nozzles moving in the movement direction. A second printing process that repeats the dot forming operation,
A printing method for performing
In the first printing process and the second printing process, a plurality of dot rows formed by other dot forming operations are sandwiched between the dot rows formed by one dot forming operation. ,
The printing method according to claim 1, wherein a formation order of the plurality of dot rows sandwiched in the first printing process is equal to the formation order in the second printing process.
According to such a printing method, it is possible to improve the image quality of the entire print image by bringing the image quality of the print image by the first print processing and the second print processing close to the same quality.

A transport unit for transporting the medium in the transport direction;
A moving body that moves a plurality of nozzles arranged in the transport direction in the movement direction;
A printing apparatus comprising:
A first operation of repeating a transport operation in which the transport unit transports the medium by a predetermined transport amount and a dot forming operation in which ink is ejected from the plurality of moving nozzles to form a plurality of dot rows on the medium. Printing process,
A transport operation in which the transport unit transports the medium with a transport amount different from the predetermined transport amount, and a dot forming operation in which ink is ejected from the plurality of moving nozzles to form a plurality of dot rows on the medium. And a second printing process that repeats
A program for executing
In the first printing process and the second printing process, a plurality of dot rows formed by other dot forming operations are sandwiched between the dot rows formed by one dot forming operation. ,
A program characterized in that the formation order in the first printing process of the plurality of dot rows sandwiched between is equal to the formation order in the second printing process.
According to such a program, it is possible to improve the image quality of the entire print image by bringing the image quality of the print image by the first print processing and the second print processing close to the same quality.

=== Configuration of Printing System ===
Next, an embodiment of a printing system (computer 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 electrically 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. The display device 120 has a display and displays a user interface such as an application program or a printer driver. The input device 130 is, for example, a keyboard 130A or a mouse 130B, and is used for operating an application program, setting a printer driver, or the like along a user interface displayed on the display device 120. As the recording / reproducing device 140, for example, a flexible disk drive device 140A or a CD-ROM drive device 140B is used.

  A printer driver is installed in the computer 110. The printer driver is a program for realizing the function of displaying the user interface on the display device 120 and the function of converting the 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. In addition, this program is comprised from the code | cord | chord for implement | achieving various functions.

  The “printing apparatus” means the printer 1 in a narrow sense, but means a system of the printer 1 and the computer 110 in a broad sense.

=== 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. Hereinafter, of the halftone processed data, 1-bit data is referred to as binary data, and 2-bit data is referred to as multi-value data.

  The rasterization process is a process of changing matrix 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 of this embodiment. FIG. 5 is a schematic diagram of the overall configuration of the printer of this embodiment. FIG. 6 is a cross-sectional view of the overall configuration of the printer of this embodiment. Hereinafter, the basic configuration of the printer of this embodiment will be described.

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

  The transport unit 20 is for feeding a medium (for example, the paper S) to a printable position and transporting the paper by a predetermined transport amount in a predetermined direction (hereinafter referred to as a transport direction) during printing. That is, the transport unit 20 functions as a transport mechanism (transport means) that transports paper. 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. However, in order for the transport unit 20 to function as a transport mechanism, all of these components are not necessarily required. The paper feed roller 21 is a roller for automatically feeding the paper inserted into the paper insertion slot into the printer. The paper feed roller 21 has a D-shaped cross section, and the length of the circumferential portion is set to be longer than the transport distance to the transport roller 23. 23 can be conveyed. The transport motor 22 is a motor for transporting paper in the transport direction, and is constituted by a DC motor. 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 printed paper S to the outside of the printer. The paper discharge roller 25 rotates in synchronization with the transport roller 23.

  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. (Thus, the head moves along the moving direction.) The carriage 31 detachably holds an ink cartridge that stores ink. The carriage motor 32 is a motor for moving the carriage 31 in the movement direction, and is constituted by a DC motor.

  The head unit 40 is for ejecting ink onto paper. The head unit 40 has a head 41. The head 41 has a plurality of nozzles that are ink discharge portions, and discharges ink intermittently from each nozzle. The head 41 is provided on the carriage 31. Therefore, 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 is for detecting the position of the carriage 31 in the moving direction. The rotary encoder 52 is for detecting the rotation amount of the transport roller 23. The paper detection sensor 53 is for detecting the position of the leading edge of the paper to be printed. The paper detection sensor 53 is provided at a position where the position of the leading edge of the paper can be detected while the paper feed roller 21 feeds the paper toward the transport roller 23. The paper detection sensor 53 is a mechanical sensor that detects the leading edge of the paper by a mechanical mechanism. More specifically, the paper detection sensor 53 has a lever that can rotate in the transport direction, and this lever is disposed so as to protrude into the paper transport path. For this reason, since the leading edge of the paper comes into contact with the lever and the lever is rotated, the paper detection sensor 53 detects the position of the leading edge of the paper by detecting the movement of the lever. The optical sensor 54 is attached to the carriage 31. The optical sensor 54 detects the presence or absence of paper by the light receiving unit detecting reflected light of light irradiated on the paper from the light emitting unit. The optical sensor 54 detects the position of the edge of the paper while being moved by the carriage 41. Since the optical sensor 54 optically detects the edge of the paper, the detection accuracy is higher than that of the mechanical paper detection sensor 53.

  The controller 60 is a control unit (control means) for controlling the printer. The controller 60 includes an interface unit 61, a CPU 62, a memory 63, and a unit control circuit 64. The interface unit 61 is for transmitting and receiving 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 the program of the CPU 62, a work area, and the like, and has storage means 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 printing operation>
FIG. 7 is a flowchart of processing during printing. Each process described below is executed by the controller 60 controlling each unit in accordance with a program stored in the memory 63. This program has a code for executing each process.

  The controller 60 receives a print command from the computer 110 via the interface unit 61 (S001). This print command is included in the header of print data transmitted from the computer 110. Then, the controller 60 analyzes the contents of various commands included in the received print data, and performs the following paper feed processing, transport processing, ink ejection processing, and the like using each unit.

  First, the controller 60 performs a paper feed process (S002). The paper feed process is a process of 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 controller 60 rotates the paper feed roller 21 and sends the paper to be printed to the transport roller 23. The 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.

  Next, the controller 60 performs a dot formation operation (S003). The dot forming operation is a process of forming dots on paper by intermittently ejecting ink from a head that moves in the moving direction. The controller 60 drives the carriage motor 32 to move the carriage 31 in the movement direction. Then, the 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 land on the paper, dots are formed on the paper.

  Next, the controller 60 performs a conveyance process (S004). The conveyance process is a process of moving the paper relative to the head along the conveyance direction. The 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 operation.

  Next, the controller 60 determines whether or not to discharge the paper being printed (S005). If there is still data to be printed on the paper being printed, no paper is discharged. Then, the controller 60 alternately repeats the dot formation operation and the conveyance process until there is no data to be printed, and gradually prints an image composed of dots on paper. When there is no more data for printing on the paper being printed, the controller 60 discharges the paper. The controller 60 discharges the printed paper to the outside 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.

  Next, the controller 60 determines whether or not to continue printing (S006). 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.

<About nozzle>
FIG. 8 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 group K, a cyan ink nozzle group C, a magenta ink nozzle group M, and a yellow ink nozzle group Y are formed. Each nozzle group includes a plurality of nozzles (180 in this embodiment) that are ejection openings for ejecting ink of each color.

  The plurality of nozzles of each nozzle group 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 inch), k = 4. Further, even if the nozzle pitch is the same, if the dot pitch in the transport direction is 1440 dpi (1/1440 inch), k = 8. In the following description, the nozzle pitch is 180 dpi and the dot pitch is 720 dpi unless otherwise specified.

  The nozzles in each nozzle group 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.

=== Printing method ===
The printer driver generates print data for interlaced printing or overlap printing according to the contents set by the user on the interface.

<Interlace method 1>
First, an interlaced printing method will be described. Here, the “interlace method” means a printing method in which raster lines that are not recorded are sandwiched between raster lines that are recorded in one pass. The “pass” refers to an operation (dot formation operation) in which the nozzle moves once in the movement direction. A “raster line” is a row of pixels lined up in the movement direction, and is also called a scanning line. Further, the “pixel” is a square grid which is virtually defined on the printing medium in order to define the position where the ink droplet is landed and the dot is recorded.

  9A and 9B are explanatory diagrams of the interlace method. For convenience of explanation, the head (or nozzle group) 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. In addition, the number of nozzles arranged in the transport direction is originally 180, but here the number of nozzles is set to 8 for simplicity of explanation. Further, although the head has a plurality of nozzle groups, in order to simplify the description, one nozzle group of the head will be described here.

  In the figure, nozzles indicated by black circles are nozzles that can eject ink, and nozzles indicated by white circles are nozzles that cannot eject ink. FIG. 9A shows the head position and dot formation in pass 1 to pass 4, and FIG. 9B shows the head position and dot formation in pass 1 to pass 6.

  In the interlace method, each time the paper is transported at a constant transport amount F in the transport direction, 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, the number N (integer) of nozzles that can eject ink is relatively prime to k, and the carry amount F is set to N · D.

  In the figure, the head has eight nozzles arranged along the transport direction. However, since the nozzle pitch k is 4, not all nozzles can be used in order to satisfy the condition for performing the interlace method, “N and k are relatively prime”. Therefore, the interlace method is performed using seven of the eight nozzles. Further, since seven nozzles are used, the paper is transported with a transport amount of 7 · D. As a result, for example, using a nozzle group having a nozzle pitch of 180 dpi (4 · D), dots are formed on the paper at a dot interval of 720 dpi (= D).

  In the drawing, the first raster line is formed by nozzle # 3 in pass 3, the second raster line is formed by nozzle # 5 in pass 2, and the third raster line is formed by nozzle # 7 in pass 1. The fourth raster line is formed by nozzle # 2 in pass 4 and a continuous raster line is formed. In pass 3 and thereafter, seven nozzles (# 2 to # 8) discharge ink, the paper is conveyed by a constant conveyance amount F (= 7 · D), and continuous raster lines are dot intervals. D.

<About the interlace method 2>
In the above description, the number of nozzles is eight in order to simplify the description. However, the actual number of nozzles is 180. The interlace method in this case will be described.
FIG. 10A is an explanatory diagram of an actual interlace method. In the figure, the relative positions of the head and the paper are shown. Here, the head has 180 nozzles arranged in the transport direction. However, since the nozzle pitch k is 4, not all nozzles can be used in order to satisfy the condition for performing the interlace method, “N and k are relatively prime”. Therefore, the interlace method is performed using 179 nozzles out of 180 nozzles. In addition, since 179 nozzles are used, the paper is carried by a carry amount of 179 · D.

  In a certain pass, the head 41 </ b> A ejects ink while moving in the moving direction to form dots (raster lines) on the area 1 of the paper. Next, the paper is conveyed at 179 · D (= 179/720 inch), and the head moves relative to the paper to the position of the head 41B in the drawing. In the next pass, the head 41B discharges ink while moving in the moving direction, and forms dots (raster lines) in the area 1 and area 2 of the paper. Here, it is assumed that such an operation is continued until the head 41E forms dots on the paper.

  FIG. 10B is an explanatory diagram of the dot formation status in each region after the head 41E forms dots on the paper. In the figure, white circles indicate pixels in which dots are not formed. A black circle indicates a pixel in which dots are formed.

  In the area 1, dots (raster lines) are formed by the four passes by the heads 41A to 41D. In the area 2, dots are formed by four passes by the head 41B to the head 41E. As described above, in an area where four passes have passed, dots are formed in all the pixels in the area. In the area 3, dots are formed by the heads 41C to 41E by three passes. As described above, in an area where three passes have passed, dots are formed in pixels of three raster lines of the four raster lines. In the region 4, dots are formed by two passes by the heads 41D and 41E. In this way, in the area where two passes have passed, dots are formed on the pixels of two raster lines of the four raster lines. In area 5, dots are formed by one pass by 41E. As described above, in an area where one pass has passed, dots are formed in pixels of one raster line of the four raster lines. In the region 6, no dot has been formed yet.

  As described above, in the interlace method, just by moving the head once (by only one pass), dots are not formed in all the pixels in the area facing the head. Specifically, it is necessary to pass k passes in order for dots to be formed in all pixels in a certain region.

<About the overlap method 1>
FIG. 11A and FIG. 11B are explanatory diagrams of the overlap method when the number of nozzles is eight. In the interlace method described above, one raster line is formed by one nozzle. On the other hand, in the overlap method, for example, one raster line is formed by two or more nozzles.

  In the overlap method, each time the paper is transported at a constant transport amount F in the transport direction, each nozzle intermittently forms a dot every several dots. Then, in another pass, dots are formed so as to complement intermittent dots already formed by other nozzles, thereby completing one raster line with a plurality of nozzles. When one raster line is completed in M passes in this way, it is defined as the overlap number M. In the figure, since each nozzle intermittently forms dots 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 the case of the above-described interlace method, the overlap number M = 1.

  In the overlap method, 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.

In the figure, the nozzle group has eight nozzles arranged along the transport direction. However, since the nozzle pitch k of the nozzle group 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 the overlap method. Therefore, the overlap method 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 group having a nozzle pitch of 180 dpi (4 · D), dots are formed on the paper at a dot interval of 720 dpi (= D). Further, in one pass, each nozzle intermittently forms dots every other dot in the movement direction. In the figure, the raster line in which two dots are drawn in the moving direction has already been completed. For example, in FIG. 11A, the first raster line to the sixth raster line have already been completed. A raster line in which one dot is drawn is a raster line in which dots are intermittently formed every other dot. For example, in the seventh and tenth raster lines, dots are intermittently formed every other dot. The seventh raster line in which dots are intermittently formed every other dot is completed by forming dots so that nozzle # 1 in pass 9 is complemented.
In pass 7 and thereafter, six nozzles (# 3 to # 8) eject ink, the paper is conveyed by a constant conveyance amount F (= 3 · D), and continuous raster lines are dot intervals. D.

FIG. 12A is an explanatory diagram of an overlap method when the number of nozzles is 180. When the number of nozzles is 180, 178 nozzles are used, and the paper is transported at a constant transport amount 89 · D.
FIG. 12B is an explanatory diagram of the dot formation status in each region.

  In the region 1, dots are formed by eight passes by the heads 41A to 41H. In the area 2, dots are formed by eight passes by the heads 41B to 41I. In this way, in the area where eight passes have passed, dots are formed in all the pixels in the area. In the area 3, dots are formed by the seven passes by the head 41C to the head 41I. In this way, in the area where seven passes have passed, three of the four raster lines are completed, and dots are formed every other dot in the remaining one raster line. In this way, the head forms dots every other dot in one raster line of the four raster lines for each pass in each region. Further, dots are formed in a staggered pattern in an area where four passes have been completed.

  Even in the overlap mode, if the head is moved once (only with one pass), dots are not formed on all the pixels in the area facing the head. Specifically, in order to form dots at all the pixels in a certain region, it is necessary to pass eight (k × M) passes. Note that the overlap method is a printing method included in the concept of the interlace method because raster lines that are not recorded are sandwiched between raster lines that are recorded in one pass.

=== Borderless printing ===
“Borderless printing” is printing in which printing is performed on the entire surface of paper. By performing “borderless printing”, an image can be printed on the entire surface of the paper without creating a margin. Here, a printing method of “marginless printing” will be described. Whether or not “marginless printing” is to be performed is determined by the printer driver based on the contents set by the user on the interface.

  FIG. 13 is an explanatory diagram of an ink discharge area at the time of borderless printing. In the figure, a thick rectangle on the inner side indicates a paper area (paper size). In the same figure, the thick bold rectangle on the outer side shows the ink ejection area (however, this figure shows the ink ejection area relative to the paper).

As described above, in borderless printing, the printer prints on the entire surface of the paper by ejecting ink over a wider area than the paper. As a result, even if the paper is transported obliquely, an image is printed on the entire surface of the paper.
However, since the ink is ejected to a wider area than the paper, the ink ejected to the shaded area in the figure does not land on the paper but land on the platen 24. However, when ink lands on the portion of the platen 24 that supports the paper, the back surface of the paper is soiled with ink.
Therefore, in the present embodiment, the platen 24 has a groove. This groove has a shape recessed from the portion of the platen that supports the paper. The ink that does not land on the paper is landed on this groove.

  14A to 14C are explanatory diagrams of ink ejection when borderless printing is performed. In the figure, the paper S is conveyed from right to left in the figure. The head 41 ejects ink while reciprocating in a direction perpendicular to the paper surface. The platen 24 has a groove 241 for performing borderless printing.

  FIG. 14A is an explanatory diagram when borderless printing is performed on the upper end portion of the paper. At this time, if ink is ejected from all the nozzles, the ink lands on the portion of the platen 24 that supports the paper, and the back surface of the paper is soiled. Therefore, ink is ejected only from the nozzles facing the groove 241 to form an image on the paper. As a result, ink that does not land on the paper lands on the groove 241. Hereinafter, such printing is referred to as “upper end printing”.

  FIG. 14B is an explanatory diagram when printing the central portion of the paper. At this time, even if ink is ejected from all the nozzles, the ink lands on the paper and the ink does not land on the platen 24. Therefore, ink is ejected from all nozzles to form an image on paper. Hereinafter, such printing is referred to as “normal printing”.

  FIG. 14C is an explanatory diagram when borderless printing is performed on the lower end portion of the paper. At this time, if ink is ejected from all the nozzles, the ink lands on the portion of the platen 24 that supports the paper, and the back surface of the paper is soiled. Therefore, ink is ejected only from the nozzles facing the groove 241 to form an image on the paper. As a result, ink that does not land on the paper lands on the groove 241. Hereinafter, such printing is referred to as “bottom edge printing”.

Comparing upper end printing (FIG. 14A) and normal printing (FIG. 14B), the number of nozzles that can eject ink is different. This is because ink can be ejected from all nozzles in normal printing, whereas ink cannot be ejected from only nozzles facing the grooves 241 in upper end printing.
On the other hand, in the interlace method and the overlap method, the carry amount F is determined by the number of usable nozzles. When the number of usable nozzles is N, the carry amount F is (N / M) · D (M = 1 in the interlace method, and M in the overlap method in which one raster line is printed by two nozzles. = 2).
For this reason, the transport amount of the paper at the upper end printing and the transport amount of the paper at the normal printing are different. For the same reason, the transport amount of paper at the lower end printing and the transport amount of paper during normal printing are also different.

When performing borderless printing on a piece of paper, the paper has an area where an image is printed by upper end printing, an area where an image is printed by normal printing, and an area where an image is printed by lower end printing. Exists. That is, the print image is printed by joining the print image by the upper end printing, the print image by the normal printing, and the print image by the lower end printing. However, if the print qualities of the upper-end printing, normal printing, and lower-end printing are different, the difference in image quality among the areas is conspicuous, and the image quality of the entire printed image is deteriorated. In order to prevent such deterioration in image quality, it is important to make the image quality of the printed images obtained by the printing of the upper end printing, the normal printing, and the lower end printing with different transport amounts close to the same quality.
Hereinafter, it will be described how the image quality of a print image obtained by upper-end printing (or lower-end print) is brought close to the image quality of a print image obtained by normal printing.

=== Raster Line Formation Order of this Embodiment ===
The printer driver creates print data so that the raster lines are formed in the order described below. In the following description, the total number of nozzles is 180, and the number of nozzles facing the groove 241 is 30. In addition, it is assumed that the nozzle # 75 to the nozzle # 104 face the groove 241.

<Interlace method 1>
15A to 15C are explanatory diagrams of the dot formation order by the interlace method.

(Normal printing)
FIG. 15A is an explanatory diagram of the dot formation order during normal printing. Note that interlaced normal printing has already been described with reference to FIGS. 10A and 10B. That is, in the interlaced normal printing, 179 nozzles (nozzle # 1 to nozzle # 179) out of 180 nozzles are used, and the carry amount F is 179 · D (= 179/720 inch). .

Here, the dot formation order will be described focusing on the region 2 in FIG. 10A.
Before the first pass (dot formation operation), as shown in “Before the first pass” in FIG. 15A, no dots are formed. In the area 2, no dots are formed until the head 41B is passed. When the head 41B moves in the moving direction and ejects ink, the first pass (dot forming operation) in the region 2 is performed.

  After the first pass, as shown in “After the first pass” in FIG. 15A, raster lines are formed in the region 2 with a nozzle pitch apart. In other words, in the area 2, one of the four raster lines is printed. The arrow in the figure indicates the position of the raster line formed for the first time in the region 2. Also, in the drawing, of the area 2, the area sandwiched between the raster lines formed by the nozzle # 179 (the most upstream nozzle in the transport direction capable of ejecting ink) and the nozzle # 178 is shown.

  Next, the transport unit transports the paper in the transport direction with a transport amount of 179 · D. As a result, the region 2 moves relatively downstream with respect to the head 41. The relative position of the head 41 at this time is the position shown by the head 41C in FIG. 10A. Since the 180 nozzles are arranged at a nozzle pitch of 4 · D, after the transport unit transports the paper at 179 · D, the head is positioned at the “downstream” position of the raster line formed in the first pass. 41 nozzles will be located. For example, after transport, the nozzle # 134 is positioned “downstream” of the raster line formed by the nozzle # 179.

Therefore, in the second pass in the region 2, as shown in “after the second pass” in FIG. 15A, a raster line is formed adjacent to the “downstream side” of the already formed raster line. . For example, the nozzle # 134 forms a raster line adjacent to the “downstream side” of the raster line formed by the nozzle # 179. (Although not shown, nozzle # 133 forms a raster line adjacent to the “downstream side” of the raster line formed by nozzle # 178.)
Similarly, after the third pass, since the transport unit transports the paper with a transport amount of 179 · D, a raster line is formed adjacent to the “downstream side” of the raster line formed in the previous pass. The

[Comparative Example 1]
FIG. 15B is an explanatory diagram of the dot formation order during upper end printing in Comparative Example 1. This figure shows the dot formation order in the region located near the top edge of the paper. 15A and 15B are drawn side by side in the left-right direction on the paper surface for explanation, but in reality, the region shown in FIG. 15A is the region shown in FIG. 15B (the region located near the top edge of the paper). Rather than the upstream side in the transport direction.

  As described above, the number of nozzles facing the groove 241 is 30 (nozzle # 75 to nozzle # 104). In top-end printing, ink can be ejected only from the nozzles facing the grooves, so only these 30 nozzles can be used. On the other hand, in order to perform the interlace method in the top-end printing, it is necessary to satisfy the condition of “N and k (= 4) being relatively prime”, which is a condition of the interlace method. Therefore, in Comparative Example 1, the largest number of 29 nozzles (nozzle # 75 to nozzle # 103) that satisfy this condition is used.

  When the number of nozzles that can eject ink is 29, the amount of paper transported by the transport unit is 29 · D. Since the 29 nozzles are arranged at a nozzle pitch of 4 · D, after the transport unit transports the paper at 29 · D, the head is positioned at the “upstream side” position of the raster line formed in the first pass. 41 nozzles will be located. For example, after conveyance, the nozzle # 95 is positioned “upstream” of the raster line formed by the nozzle # 102.

Therefore, in the second pass near the upper end, as shown in “after the second pass” in FIG. 15B, a raster line is formed adjacent to the “upstream side” of the already formed raster line. . For example, nozzle # 95 forms a raster line adjacent to the “upstream side” of the raster line formed by nozzle # 102 (not shown, but nozzle # 96 is a raster line formed by nozzle # 103. A raster line is formed adjacent to the “upstream side” of the).
Similarly, after the third pass, the transport unit transports the paper with a transport amount of 29 · D, so a raster line is formed adjacent to the “upstream side” of the raster line formed in the previous pass. The

Comparing the dot formation order of FIG. 15A and the dot formation order of FIG. 15B, it can be understood that the dot formation order between raster lines formed in the first pass is different. For example, in FIG. 15A, the three raster lines between the raster lines formed in the first pass are formed in order from the raster line on the upstream side in the transport direction. On the other hand, in FIG. 15B, the three raster lines between the raster lines formed in the first pass are formed in order from the raster line on the downstream side in the transport direction.
As in Comparative Example 1, when the raster line formation order (dot formation order) differs between normal printing and upper-end printing (or lower-end printing), the image quality of the printed image deteriorates.

(Upper end printing of this embodiment)
FIG. 15C is an explanatory diagram of the dot formation order during upper-end printing according to the present embodiment. This figure shows the dot formation order in the region located near the top edge of the paper. 15A and 15C are drawn side by side in the horizontal direction of the drawing for the sake of explanation, but in reality, the region shown in FIG. 15A is the region shown in FIG. 15C (the region located near the top edge of the paper). Rather than the upstream side in the transport direction.

  As described above, only 30 nozzles (nozzle # 75 to nozzle # 104) can be used in the upper end printing. On the other hand, in order to perform the interlace method in the upper end printing, it is necessary to satisfy the interlace method condition “N and k are relatively prime” (N is the number of nozzles used, and k is the nozzle pitch k). -An integer to indicate D). However, if the maximum of 29 nozzles satisfying this condition are used, the dot formation order is different from that during normal printing as in Comparative Example 1 above.

  Therefore, in this embodiment, 27 nozzles (nozzle # 75 to nozzle # 101) are used. That is, the remainder when N (number of nozzles to be used) is divided by k (nozzle pitch k · D) is made equal in normal printing and upper-end printing. In the normal printing of this embodiment, the number N of nozzles to be used is 179, and k is 4 (nozzle pitch 4 · D), so the remainder when N is divided by k is 3. On the other hand, in the upper end printing of this embodiment, the number N of nozzles used is 27 and k is 4, so the remainder when N is divided by k is 3, which is equal to that during normal printing. In the upper end printing of Comparative Example 1 described above, this remainder is 1, which is different from that during normal printing.

When the number of nozzles that can eject ink is 27, the amount of paper transported by the transport unit is 27 · D. Since the 27 nozzles are arranged at a nozzle pitch of 4 · D, after the transport unit transports the paper at 27 · D, the head is positioned at the “downstream” position of the raster line formed in the first pass. 41 nozzles will be located. For example, after transport, the nozzle # 94 is positioned “downstream” of the raster line formed by the nozzle # 101.
Therefore, in the second pass near the upper end, as shown in “after the second pass” in FIG. 15C, a raster line is formed adjacent to the “downstream side” of the already formed raster line. . For example, the nozzle # 94 forms a raster line adjacent to the “downstream side” of the raster line formed by the nozzle # 101 (although not shown, the nozzle # 93 is a raster line formed by the nozzle # 100). A raster line is formed adjacent to the “downstream side” of FIG.
Similarly, after the third pass, the transport unit transports the paper with a transport amount of 27 · D. Therefore, a raster line is formed adjacent to the “downstream side” of the raster line formed in the previous pass. The

Comparing the dot formation order of FIG. 15A and the dot formation order of FIG. 15C, it can be understood that the dot formation order between the raster lines formed in the first pass is the same. For example, in FIG. 15A, the three raster lines between the raster lines formed in the first pass are formed in order from the raster line on the upstream side in the transport direction. Similarly, in FIG. 15C, the three raster lines between the raster lines formed in the first pass are formed in order from the raster line on the upstream side in the transport direction.
As described above, in this embodiment, since the raster line formation order (dot formation order) is the same during normal printing and upper-end printing (or lower-end printing), the image quality of the printed image is improved. In the interlace method, unlike the overlap method described later, if the raster line formation order is the same for normal printing and top-end printing (or bottom-end printing), the dot formation order is also the same.

<Interlaced printing 2>
In the above embodiment, k = 4. Therefore, even if the raster line formation order is different, it is common in that “the raster line formed in the next pass is located next to the raster line formed in the previous pass.” The difference between this embodiment and the comparative example may be small. However, as k increases, the difference in image quality may be noticeable. In particular, when there are three or more numbers of k that are relatively prime and less than k, a state in which a difference in image quality is noticeable occurs.
For example, in the above-described embodiment, k is 4, and there are only two numbers (1 and 3) that are relatively prime 4 or less. However, for example, when k becomes 8, there are four (1, 3, 5, 7) that are relatively prime numbers of 8 or less. In such a case, a state in which a difference in image quality is noticeable occurs. In the following, an interlace method for k = 8 (dot pitch D = 1/1440 inch, nozzle pitch 1/180 inch (= 8 · D) will be described.

(Normal printing)
FIG. 16A is an explanatory diagram of the dot formation order during normal printing when k = 8. In this case, in order to satisfy the conditions of the interlace method, 179 nozzles (nozzle # 1 to nozzle # 179) out of 180 nozzles are used, and the carry amount F is 179 · D (= 179/1440 inches). It is. Note that the remainder when N is divided by k is 3.
As shown in the figure, during normal printing, the transport unit transports the paper with a transport amount of 179 · D, so the next “3 · D upstream” of the raster line formed in the previous pass is A raster line formed by a pass is located.
Thus, if the remainder when N is divided by k is other than 1 or k−1, the raster line of the next pass can be formed without being adjacent to the raster line formed in the previous pass. For this reason, the time from when a raster line is formed to when the raster line is formed next to the raster line becomes longer, and it is possible to reduce the flow of the ink of the raster line to the adjacent raster line. Can suppress bleeding.

[Comparative Example 2]
FIG. 16B is an explanatory diagram of the dot formation order during upper end printing in Comparative Example 2 when k = 8. Here, 25 nozzles are used for comparison. In this case, the remainder when N is divided by k is 1, which is different from that in normal printing.
As shown in the figure, in Comparative Example 2, since the transport unit transports the paper with a transport amount of 25 · D, the raster formed in the next pass is adjacent to the raster line formed in the previous pass. The line is located.
Thus, if the remainder when N is divided by k is 1 or k-1, the raster line of the next pass is formed adjacent to the raster line formed in the previous pass. For this reason, the time from when a raster line is formed to when the raster line is formed next to the raster line is shortened, and the ink of the raster line is likely to spread on the adjacent raster line.
That is, the image quality of the print image in the print area of the upper end print in the comparative example is significantly different from the image quality of the print image in the print area of the normal print. For this reason, when the print image is printed on one sheet of paper by the upper end printing and the normal printing of the comparative example, the image quality differs depending on the region, and the image quality of the entire print image is lowered.

(Upper end printing of this embodiment)
FIG. 16C is an explanatory diagram of the dot formation order during upper end printing according to the present embodiment when k = 8. Here, 27 nozzles are used. In this case, the remainder when N is divided by k is 3, which is the same as in normal printing.
As shown in the drawing, in the upper end printing of the present embodiment, since the transport unit transports the paper with the transport amount of 27 · D, “3 · D upstream” of the raster line formed in the previous pass. Next, a raster line formed by the next pass is located.
Therefore, the raster line of the next pass can be formed without being adjacent to the raster line formed in the previous pass. The raster line formation order (dot formation order) is the same as that during normal printing. For this reason, even if the print image is printed on one sheet of paper by the upper end printing and the normal printing of the present embodiment, the image quality is almost equal in any region, and the image quality of the entire print image is improved.

<About the overlap method 1>
FIG. 17A to FIG. 17C are explanatory diagrams of the dot formation order by the overlap method.

(Normal printing)
FIG. 17A is an explanatory diagram of the dot formation order during normal printing. Note that overlap-type normal printing has already been described with reference to FIGS. 12A and 12B. That is, in the normal printing of the overlap method, 178 nozzles (nozzle # 1 to nozzle # 178) out of 180 nozzles are used, and the carry amount F is 89 · D.

Here, the dot formation order will be described focusing on the region 2 in FIG. 12A.
Before the first pass (dot forming operation), as shown in “Before the first pass” in FIG. 17A, no dots are formed. In the area 2, the first pass in the area 2 is performed by the head 41B moving in the moving direction and ejecting ink.

  In the overlap method, a raster line is not completed in one pass, and the head forms dots only in even-numbered pixels or odd-numbered pixels in the raster line. In the present embodiment, it is assumed that the head forms dots at odd-numbered pixels in the raster line in the first pass. A raster line in which dots are formed every other dot (raster line in which dots are formed only in even-numbered pixels or odd-numbered pixels) is referred to as an “incomplete raster line”.

  After the first pass, as shown in “After the first pass” in FIG. 17A, incomplete raster lines are formed in the region 2 with a nozzle pitch apart. The arrow in the figure indicates the position of the unfinished raster line formed in the region 2 for the first time. Also, in the drawing, of the region 2, the region sandwiched between the nozzle # 178 (the most upstream nozzle in the transport direction capable of ejecting ink) and the incomplete raster line formed by the nozzle # 177 is shown.

  Next, the transport unit transports the paper in the transport direction by a transport amount of 89 · D. As a result, the region 2 moves relatively downstream with respect to the head 41. The relative position of the head 41 at this time is the position indicated by the head 41C in FIG. 12A. Since the 180 nozzles are arranged at a nozzle pitch of 4 · D, after the transport unit transports the paper at 89 · D, it is positioned at the “upstream” position of the unfinished raster line formed in the first pass. The nozzle of the head 41 is positioned. For example, after conveyance, the nozzle # 155 is positioned “upstream” of the incomplete raster line formed by the nozzle # 177.

Therefore, in the second pass in the area 2, as shown in “after the second pass” in FIG. 17A, a raster line is formed adjacent to the “upstream side” of the already formed raster line. . For example, nozzle # 155 forms a raster line adjacent to the “upstream side” of the incomplete raster line formed by nozzle # 177. However, the raster line formed by nozzle # 155 here is an incomplete raster line in which dots are formed only in even-numbered pixels. (Although not shown, nozzle # 156 forms an incomplete raster line adjacent to the “upstream side” of the incomplete raster line formed by nozzle # 178.)
Similarly, after the third pass, the transport unit transports with a transport amount of 89 · D, so a raster line is formed adjacent to the “upstream side” of the raster line formed in the previous pass. In the fifth to eighth passes, the head intermittently forms dots every other dot so as to complement the dots of the incomplete raster lines formed by the first to fourth passes.

[Comparative Example 3]
FIG. 17B is an explanatory diagram of a dot formation order during upper end printing in Comparative Example 3. This figure shows the dot formation order in the region located near the top edge of the paper. 17A and 17B are drawn side by side in the horizontal direction of the drawing for the sake of explanation, but in reality, the region shown in FIG. 17A is the region shown in FIG. 17B (the region located near the top edge of the paper). Rather than the upstream side in the transport direction.

  As described above, the number of nozzles facing the groove 241 is 30 (nozzle # 75 to nozzle # 104). In top-end printing, ink can be ejected only from the nozzles facing the grooves, so only these 30 nozzles can be used. On the other hand, in order to perform the overlap method in top-end printing, it is necessary to satisfy the condition of overlap method “N / M and k are relatively prime”. Therefore, in Comparative Example 3, the maximum 30 nozzles (nozzle # 75 to nozzle # 104) satisfying this condition are used.

  When the number of nozzles that can eject ink is 30, the amount of paper transported by the transport unit is 15 · D. Since 30 nozzles are arranged at a nozzle pitch of 4 · D, after the transport unit transports at 15 · D, the head is positioned at the “downstream” position of the unfinished raster line formed in the first pass. 41 nozzles will be located. For example, after conveyance, the nozzle # 100 is positioned “downstream” of the incomplete raster line formed by the nozzle # 104.

Therefore, in the second pass near the upper end, as shown in “after the second pass” in FIG. 17B, a raster line is formed adjacent to the “downstream side” of the already formed incomplete raster line. Is done. For example, the nozzle # 100 forms a raster line adjacent to the “downstream side” of the incomplete raster line formed by the nozzle # 104. However, the raster line formed by the nozzle # 100 here is an incomplete raster line in which dots are formed only in even-numbered pixels. (Although not shown, nozzle # 99 forms an incomplete raster line adjacent to the “downstream side” of the incomplete raster line formed by nozzle # 103.)
Similarly, after the third pass, the transport unit transports with a transport amount of 15 · D, so a raster line is formed adjacent to the “downstream side” of the raster line formed in the previous pass. In the fifth to eighth passes, the head intermittently forms dots every other dot so as to complement the dots of the incomplete raster lines formed by the first to fourth passes.

Comparing the dot formation order of FIG. 17A and the dot formation order of FIG. 17B, it can be understood that the dot formation order between unfinished raster lines formed in the first pass is different. For example, in FIG. 17A, an unfinished raster line is first formed from the downstream side in the transport direction between unfinished raster lines formed in the first pass, and then the dots of the unfinished raster are complemented. A raster line on the downstream side in the direction is formed. On the other hand, in FIG. 17B, between the incomplete raster lines formed in the first pass, an incomplete raster line is first formed from the upstream side in the transport direction, and then the dots of the incomplete raster line are complemented. A raster line on the upstream side in the transport direction is formed.
As in Comparative Example 3, if the raster line formation order (dot formation order) differs between normal printing and upper-end printing (or lower-end printing), the image quality differs depending on the region, and the print image quality deteriorates. To do.

(Upper end printing of this embodiment)
FIG. 17C is an explanatory diagram of a dot formation order during upper-end printing according to the present embodiment. This figure shows the dot formation order in the region located near the top edge of the paper. 17A and 17C are drawn side by side in the left-right direction on the paper surface for explanation, but in reality, the region shown in FIG. 17A is the region shown in FIG. 17C (the region located near the top edge of the paper). Rather than the upstream side in the transport direction.

  As described above, only 30 nozzles (nozzle # 75 to nozzle # 104) can be used in the upper end printing. On the other hand, in order to perform the overlap method in the upper end printing, it is necessary to satisfy the condition of the overlap method “N / M and N are relatively prime”. However, if the maximum of 30 nozzles satisfying this condition are used, the dot formation order is different from that during normal printing as in the above comparative example.

  Therefore, in this embodiment, 26 nozzles (nozzle # 75 to nozzle # 100) are used. That is, the remainder when N / M (number of nozzles used / number of overlaps) is divided by k is made equal in normal printing and top-end printing. In the normal printing of this embodiment, the number of nozzles used is 178, the number of overlaps is 2, and k is 4, so the remainder when N / M is divided by k is 1. On the other hand, in the upper end printing of this embodiment, the number of nozzles N to be used is 26, the number of overlaps is 2, and k is 4, so the remainder when N / M is divided by k is 1. It is equal to normal printing. In the upper end printing of Comparative Example 3 described above, this remainder is 3, which is different from that during normal printing.

  When the number of nozzles that can eject ink is 26, the amount of paper transported by the transport unit is 13 · D. Since the 26 nozzles are arranged at a nozzle pitch of 4 · D, after the transport unit transports the paper at 13 · D, it is positioned at the “upstream” position of the unfinished raster line formed in the first pass. The nozzle of the head 41 is positioned. For example, after the conveyance, the nozzle # 96 is positioned on the “upstream side” of the incomplete raster line formed by the nozzle # 99.

Therefore, in the second pass near the upper end, a raster line is formed adjacent to the “upstream side” of the already formed raster line, as shown in “after the second pass” in FIG. 17C. . For example, the nozzle # 96 forms a raster line adjacent to the “upstream side” of the raster line formed by the nozzle # 99. However, the raster line formed by nozzle # 96 here is an incomplete raster line in which dots are formed only in even-numbered pixels. (Although not shown, the nozzle 97 forms an incomplete raster line adjacent to the “upstream side” of the incomplete raster line formed by the nozzle # 100.)
Similarly, after the third pass, the transport unit transports with a transport amount of 13 · D, so that a raster line is formed adjacent to the “upstream side” of the raster line formed in the previous pass. In the fifth to eighth passes, the head intermittently forms dots every other dot so as to complement the dots of the incomplete raster lines formed by the first to fourth passes.

  Comparing the dot formation order of FIG. 17A and the dot formation order of FIG. 17C, it can be understood that the dot formation order between unfinished raster lines formed in the first pass is the same. For example, in FIG. 17A, an unfinished raster line is first formed from the downstream side in the transport direction between the raster lines formed in the first pass, and then the dots of the unfinished raster are complemented to downstream in the transport direction. A raster line on the side is formed. Similarly, in FIG. 17C, an incomplete raster line is first formed from the downstream side in the transport direction between the incomplete raster lines formed in the first pass, and then the dots of the incomplete raster line are complemented. A raster line on the downstream side in the transport direction is formed.

  As described above, in this embodiment, the dot formation order is the same during normal printing and during upper-end printing (or during lower-end printing). Therefore, even if a print image is printed on one sheet of paper by top-end printing and normal printing, the image quality is almost the same in any region, and the image quality of the entire print image is improved.

[Comparative Example 4]
In the interlaced embodiment and the overlapped embodiment described above, the remainder when N / M is divided by k is made equal in normal printing and top-end printing. As a result, the raster line formation order in normal printing and the raster line formation order in upper-end printing can be printed equally.
However, in the overlap method, the dot formation order of normal printing and top-end printing is as long as the condition that “the remainder when N / M is divided by k is equal in normal printing and top-end printing” is satisfied. , Not necessarily equal. This point will be described in detail below.

18A and 18B are explanatory diagrams of the dot formation order of the overlap method. FIG. 18A is an explanatory diagram of a dot formation order during upper end printing according to the present embodiment. Therefore, FIG. 18A is the same as FIG. 17C described above.
FIG. 18B is an explanatory diagram of the dot formation order during upper end printing in Comparative Example 4. In Comparative Example 4, as in the upper end printing of the present embodiment, 26 nozzles (nozzle # 75 to nozzle # 100) are used, and the transport unit transports the paper with a transport amount of 13 · D. Therefore, in Comparative Example 4, the condition that “the remainder when N / M is divided by k is equal between normal printing and top-end printing” is satisfied. Thereby, also in the comparative example 4, the positional relationship between the unfinished raster lines and the nozzles already formed after the conveyance becomes equal in the normal printing and the upper end printing (the same as the upper end printing in the present embodiment).

However, the comparative example 4 is different from the upper end printing of the present embodiment in the position where the head forms dots.
That is, in the upper end printing of the present embodiment, as in normal printing, the head forms dots on “odd-numbered” pixels in the first pass, and dots on “even-numbered” pixels in the second pass. In the third pass, dots are formed in “odd-numbered” pixels, and in the fourth pass, dots are formed in “even-numbered” pixels. In the fifth to eighth passes, in order to complement the dots of the unfinished raster lines formed by the first to fourth passes, the head is “even number” in the fifth pass and “ Dots are formed on “odd-numbered” pixels, “even-numbered” pixels in the seventh pass, and “odd-numbered” pixels in the eighth pass. That is, in the upper end printing of the present embodiment, the head alternately forms dots on the “even-numbered” or “odd-numbered” pixels in four consecutive passes, and the order is repeated in the four consecutive passes thereafter. The dots are alternately formed to form dots at “even-numbered” or “odd-numbered” pixels.

On the other hand, in the upper end printing of Comparative Example 4, unlike the normal printing, the heads form dots on all “odd-numbered” pixels in the first to fourth passes. In the fifth to eighth passes, in order to complement the dots of the incomplete raster lines formed in the first to fourth passes, the head forms dots on all “even-numbered” pixels.
Therefore, in Comparative Example 4, since the dot formation order is different between normal printing and upper-end printing (or lower-end printing), the image quality differs depending on the region, and the image quality of the printed image deteriorates.

  That is, FIG. 18A and FIG. 18B have the same raster line formation order but different dot formation order. In such a case, FIG. 18A in which the dot formation order in normal printing and upper-end printing (or lower-end printing) is the same is preferable because the image quality is improved.

<About the overlap method 2>
In the above-described overlap method, all nozzles of the head in the same pass form dots only in one of even-numbered pixels or odd-numbered pixels (that is, all nozzles are located at the same position in the movement direction). Dots are formed on the pixels). However, in such a dot formation method, only a part of the dot formation order of the area where the dots are formed by normal printing and the dot formation order of the areas where the dots are formed by top-end printing (or bottom-end printing). Does not match exactly. This will be described in detail below.

  FIG. 19A is an explanatory diagram of dot formation in the region 2 by the above-described overlap method. FIG. 19B is an explanatory diagram of dot formation in the region 3 by the overlap method described above. FIG. 20A is an explanatory diagram of the dot formation of the overlap method described above. In the drawing, “odd” in the head means that the head discharges dots to odd-numbered pixels. In addition, the description of “even” in the head in the figure means that the head discharges dots to even-numbered pixels. In addition, the description “Odd → even” on the paper surface in the drawing means that the dot formation operation to the even-numbered pixels is performed after the dot formation operation to the odd-numbered pixels.

  In the above-described embodiment, each time the head 41B moves intermittently to the position of the head 41J, the head is "odd (th pixel)" → "even (th pixel)" → "odd" → "even". Dots are formed on the pixels in the order of “even number” → “odd number” → “even number” → “odd number” (see the left side of FIG. 20A). In this case, in the region 2 on the paper, “odd number (th pixel)” → “even number (th pixel)” → “odd number” → “even number” → “even number” → “odd number” → “even number” → “odd number” In this order, dots are formed (see the region 2 on the right side of FIG. 20A). However, in the area 3 on the paper, “even number (th pixel)” → “odd number (th pixel)” → “even number” → “even number” → “odd number” → “even number” → “odd number” → “odd number” Dots are formed sequentially (see region 3 on the right side of FIG. 20A).

  Comparing FIG. 19A and FIG. 19B, the raster line formation order is the same, but the dot positions in the movement direction are different. For example, when the state of dot formation “after the fifth pass” is compared, the dot formation state is different. In FIG. 19A, dots are arranged in a grid pattern, but in FIG. 19B, dots are not arranged in a grid pattern.

As described above, if the dot formation order is different between the areas where the same printing process is performed (in this case, the areas 2 and 3 where the normal printing is performed), the area where the dots are formed by the normal printing. The dot formation order and the dot formation order of the area where dots are formed by upper end printing (or lower end printing) only partially match. (However, the dot formation order is different, but the raster line formation order is the same.)
Therefore, in this improved example, the head forms dots on pixels at different positions in the movement direction. That is, in the improved example, a certain nozzle forms dots on even-numbered pixels, and another nozzle forms dots on odd-numbered pixels. Thereby, the dot formation order is made equal in all the print areas as follows.

FIG. 19C is an explanatory diagram of dot formation in the region 3 by the overlap method of the improved example. FIG. 20B is an explanatory diagram of dot formation of the overlap method of the improved example.
In this improved example, 180 nozzles of one nozzle group are classified into eight groups. In the following description, the most downstream group in the transport direction is referred to as a first group, the groups are numbered in order, and the most upstream group in the transport direction is referred to as an eighth group. Specifically, the first group includes nozzles # 1 to # 22, the second group includes nozzles # 23 to # 44, the third group includes nozzles # 45 to # 66, and the fourth group. Is composed of nozzle # 67 to nozzle # 89, the fifth group is composed of nozzle # 90 to nozzle # 111, the sixth group is composed of nozzle # 112 to nozzle 133, and the seventh group is composed of nozzle # 134 to nozzle # 155. Thus, the eighth group is composed of nozzle # 156 to nozzle # 178.

  All nozzles in the same group form dots at pixels at the same position in the movement direction. For example, all nozzles in the same group form dots at even-numbered pixels. Further, different groups of nozzles can form dots at pixels at different positions in the movement direction. For example, when the first group of nozzles forms dots at odd-numbered pixels, the second group of nozzles can form dots at even-numbered pixels.

In this improved example, the first group forms dots on odd-numbered pixels, the second group forms dots on even-numbered pixels, the third group forms dots on odd-numbered pixels, and the fourth group Forms dots on even-numbered pixels, the fifth group forms dots on even-numbered pixels, the sixth group forms dots on odd-numbered pixels, and the seventh group forms dots on even-numbered pixels. In the eighth group, dots are formed in odd-numbered pixels.
As a result, the dot formation order is the same in all areas that are normally printed by the overlap method. That is, in all regions, “odd number (th pixel)” → “even number (th pixel)” → “odd number” → “even number” → “even number” → “odd number” → “even number” → “odd number” in this order. Dots are formed.

In addition, although not shown, in the upper end printing and the lower end printing, similarly, 26 nozzles that eject ink are classified into eight groups. The first group forms dots on the “odd” pixels, the second group forms dots on the “even” pixels, the third group forms dots on the “odd” pixels, The fourth group forms dots at “even” pixels, the fifth group forms dots at “even” pixels, the sixth group forms dots at “odd” pixels, The group forms dots at “even” pixels, and the eighth group forms dots at “odd” pixels.
As a result, not only the raster line formation order matches, but also the dot formation order matches.

=== 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 the printer>
In the above-described embodiment, the printer has been described. However, the present invention is not limited to this. For example, color filter manufacturing apparatus, dyeing apparatus, fine processing apparatus, semiconductor manufacturing apparatus, surface processing apparatus, three-dimensional modeling machine, liquid vaporizer, organic EL manufacturing apparatus (particularly polymer EL manufacturing apparatus), display manufacturing apparatus, film formation The same technique as that of the present embodiment may be applied to various recording apparatuses to which an ink jet technique is applied such as an apparatus and a DNA chip manufacturing apparatus. These methods and manufacturing methods are also within the scope of application. Even if this technology is applied to such a field, the liquid can be directly ejected (directly drawn) toward the object. You can go down.

<About ink>
Since the above-described embodiment is an embodiment of a printer, dye ink or pigment ink is ejected from the nozzle. However, the liquid ejected from the nozzle is not limited to such ink. For example, liquids (including water) including metal materials, organic materials (especially polymer materials), magnetic materials, conductive materials, wiring materials, film-forming materials, electronic inks, processing liquids, gene solutions, etc. are ejected from nozzles. May be. If such a liquid is directly discharged toward the object, material saving, process saving, and cost reduction can be achieved.

<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.

<About the interlace method>
In the above-described embodiment, an interlace method is used in which dots having a 720 dpi interval are formed using a nozzle group having a nozzle pitch of 180 dpi (4 · D). However, the interlace method is not limited to this. For example, the interlace method may be performed using a nozzle group having a nozzle pitch of 720 dpi (D).

  FIG. 21 is an explanatory diagram of another interlace method. In the present embodiment, the plurality of nozzles of the nozzle group are arranged at 720 dpi (= 1/720 inch) along the transport direction. When dots are formed on the paper at 720 dpi intervals, k = 1. In this embodiment, the nozzle group has 24 nozzles for simplification of description. The paper is conveyed at a constant interval of 4 · D. Also, ink is ejected from the nozzles every four nozzles, and the nozzles that eject ink are changed for each pass.

  Also in this embodiment, the interlace method can be performed so that raster lines that are not recorded are sandwiched between raster lines that are recorded in one pass. Further, in the present embodiment, there is no restriction such as “the number N of nozzles that can eject ink (integer) is relatively prime to k” as in the above-described embodiment (however, there are other restrictions).

=== Summary ===
(1) The above-described printer (printing apparatus) includes a transport unit that transports paper (medium) in the transport direction, and a carriage (moving body) that moves a plurality of nozzles arranged in the transport direction in the movement direction. . The printer can perform normal printing (first printing process) and upper-end printing or lower-end printing (second printing process). Here, in normal printing, a transport operation in which the transport unit transports paper with a predetermined transport amount, and a dot formation operation in which ink is ejected from a plurality of moving nozzles to form a plurality of dot rows on the paper. repeat. In top-end printing or bottom-end printing, a transport operation in which the transport unit transports the paper with a transport amount smaller than that in normal printing and a plurality of dot rows are formed on the paper by ejecting ink from the plurality of moving nozzles. The dot forming operation is repeated.

As described above, when a print image is formed on paper by normal printing and top-end printing (and bottom-end printing), the print image includes a region printed by normal printing and a region printed by bottom-end printing.
However, if the print quality differs between normal printing and upper-end printing (and lower-end printing), the difference in image quality between the two areas is noticeable, and the image quality of the entire printed image is deteriorated.

  Therefore, in the above-described printer, a plurality of raster lines formed by other dot forming operations are sandwiched between raster lines formed by one dot forming operation or unfinished raster lines (dot rows). The forming operation in normal printing of a plurality of sandwiched raster lines is the same as the forming order in bottom-end printing. For example, according to the interlace method shown in FIG. 15, the three raster lines sandwiched between the two raster lines formed by the nozzle # 179 and the nozzle # 178 in normal printing are sequentially formed from the upstream side in the transport direction. The three raster lines sandwiched between the two raster lines formed by the nozzle # 101 and the nozzle 100 in the upper end printing (or lower end printing) are sequentially formed from the upstream side in the transport direction.

As a result, the image quality of the print image by the upper end printing (or the lower end print) approaches the image quality of the normal print image, and the image quality of the entire print image is improved.
In other words, since the print image is formed by the ink ejected from the nozzles, the image quality of the print image differs if the way of drying the ink constituting the print image is different. The print image is composed of a plurality of raster lines arranged in the transport direction. For this reason, if the raster lines are formed in the same order in both printing processes, the ink is dried in substantially the same manner, and the image quality of the printed image formed by each printing process is the same. Thereby, the image quality of the entire printed image is improved.

(2) According to the interlace method described above, the printer forms dots on pixels that are continuous in the movement direction by a single dot formation operation. That is, the printer completes the raster line by one dot forming operation. As a result, the printer can perform high-speed printing while improving the image quality of the entire print image.

(3) According to the interlace method shown in FIGS. 15A and 15C described above, the dot pitch (the interval between dots formed on the paper) is 1/720 inch (= D), and the nozzle pitch (the number of nozzles that eject ink). (Interval in the transport direction) is 1/180 inch (= 4 · D), the number of nozzles N1 ejecting ink in normal printing (first printing process) is 179, and ink in upper end printing or lower end printing (second printing process) The number N2 of nozzles to be discharged is 27. Further, according to the interlace method 2 shown in FIGS. 16A and 16C described above, the dot pitch is 1/1440 inch (= D), the nozzle pitch is 1/180 inch (= 8 / D), and the ink in the normal printing is used. The number N1 of nozzles to be ejected is 179, and the number N2 of nozzles to eject ink in upper end printing or lower end printing is 27. That is, in any interlace system, N1 and k are relatively prime, N2 and k are mutually prime, and the remainder when N1 is divided by k is the remainder when N2 is divided by k. Is equal to

In the above-described embodiment, this condition is satisfied, so that a plurality of raster lines formed by other dot forming operations are sandwiched between raster lines (dot rows) formed by one dot forming operation. Interlace method becomes possible. In addition, the forming operation in normal printing of the sandwiched raster lines is the same as the forming order in bottom edge printing. Thereby, the image quality of the entire printed image is improved.
However, the effect cannot be obtained unless the above conditions are satisfied. For example, as shown in FIG. 21, ink may be ejected from nozzles every four nozzles, and the nozzles that eject ink may be changed for each dot forming operation. In short, it is sufficient that the raster line forming operation in the normal printing is equal to the forming order in the lower end printing.

(4) If k is not equal to a natural number smaller than k other than 1 or k−1, such as k = 4, even if the raster line formation order is different, the print image There is no significant degradation. This is because, as can be seen by comparing FIG. 15A and FIG. 15C, in any printing, “the raster line formed by the next dot forming operation is positioned next to the raster line formed by the previous dot forming operation”. This is because they are common.
However, according to the interlace scheme shown in FIGS. 16A and 16C, k = 8 in FIGS. 16A and 16C, and 3 and 5 have a relatively prime relationship with 8 in addition to 1 or 7. is there. That is, k is in a prime relationship with a natural number smaller than k other than 1 or k-1. In such a case, as can be seen by comparing FIG. 16B and FIG. 16C, the difference in the raster line formation order increases, and the printed image may be significantly degraded.
Therefore, this embodiment is particularly effective when k has a prime relationship with a natural number smaller than k other than 1 or k-1.

(5) According to the interlace method shown in FIGS. 16A and 16C described above, the remainder when the number of nozzles used is divided by k is other than 1 or k-1. If this condition is satisfied, the raster line can be formed by the next dot forming operation without being adjacent to the raster line formed by the previous dot forming operation.
For this reason, the time from when a raster line is formed to when the raster line is formed next to the raster line becomes longer, and it is possible to reduce the flow of the ink of the raster line to the adjacent raster line. Can suppress bleeding.

(6) According to the interlace method shown in FIGS. 16A and 16C described above, a raster line is formed by the next dot forming operation without being adjacent to the raster line (dot row) formed by the previous dot forming operation. can do. For this reason, the time from when a raster line is formed to when the raster line is formed next to the raster line becomes longer, and it is possible to reduce the flow of the ink of the raster line to the adjacent raster line. Can suppress bleeding.

(7) According to the overlap method described above, the printer forms dots on pixels that are continuous in the moving direction by a plurality of dot forming operations. That is, the printer completes the raster line by a plurality of dot forming operations. As a result, the printer can suppress deterioration in image quality due to nozzle manufacturing errors and improve the image quality of the entire printed image.

(8) According to the overlap method shown in FIGS. 17A and 17C, the dot pitch (interval of dots formed on the paper) is 1/720 inch (= D), and the nozzle pitch (nozzles for ejecting ink). The number of dot forming operations is 2 (= M) until the raster line is completed (dots are formed on pixels that are continuous in the moving direction) 1/180 inch (= 4 · D). ), The number N1 of nozzles ejecting ink in normal printing (first printing process) is 178, and the number of nozzles N2 ejecting ink in upper end printing or lower end printing (second printing process) is 26. That is, N1 / M and k are relatively prime, N2 / M and k are mutually prime, and the remainder when N1 / M is divided by k is N2 / M divided by k Is equal to the remainder of

In the above-described embodiment, since this condition is satisfied, a plurality of raster lines formed by other dot forming operations are included between raster lines (or unfinished raster lines) formed by one dot forming operation. An overlapping method is possible. In addition, the forming operation in normal printing of the sandwiched raster lines is the same as the forming order in bottom edge printing. Thereby, the image quality of the entire printed image is improved.
However, the effect cannot be obtained unless the above conditions are satisfied. For example, as shown in FIG. 21, ink may be ejected from nozzles every four nozzles, and the nozzles that eject ink may be changed for each dot forming operation. In short, it is sufficient that the raster line forming operation in the normal printing is equal to the forming order in the lower end printing.

(9) Similar to the interlace method in the overlap method, if “k is a prime relationship with a natural number smaller than k other than 1 or k−1”, the difference in raster line formation order is large. Therefore, the printed image may be significantly deteriorated.
Therefore, even in the overlap method, this embodiment is particularly effective when k is in a prime relationship with a natural number smaller than k other than 1 or k-1.

(10) In the overlap method, as in the case of the overlap method, if the condition that the remainder when the number of nozzles used is divided by k is other than 1 or k-1 is satisfied, the overlap is formed by the previous dot formation operation. The raster line can be formed by the next dot forming operation without being adjacent to the raster line (or the unfinished raster line).
For this reason, the time from when a raster line is formed to when the raster line is formed next to the raster line becomes longer, and it is possible to reduce the flow of the ink of the raster line to the adjacent raster line. Can suppress bleeding.

(11) In the overlap method, as in the case of the overlap method, the raster line is formed by the next dot formation operation without being adjacent to the raster line (or the unfinished raster line) formed by the previous dot formation operation. can do. For this reason, the time from when a raster line is formed to when the raster line is formed next to the raster line becomes longer, and it is possible to reduce the flow of the ink of the raster line to the adjacent raster line. Can suppress bleeding.

(12) If dots can only be formed at the same position in the movement direction in the same dot forming operation, the raster line formation order for normal printing and the raster line formation order for top-end printing (or bottom-end printing) are equal. However, the dot formation order of the two is different. For example, as shown in FIGS. 19B, 19C, and 20A, the dot formation order is different between the region 2 and the region 3.
Therefore, according to the overlap method shown in FIG. 20B described above, in one dot formation operation, the printer moves the position in the movement direction of dots formed by a certain nozzle and the movement direction of dots formed by other nozzles. Can be made different from each other. For example, in FIG. 20B, when the head 41B performs the dot forming operation, the eighth group of nozzles # 156 to # 178 forms dots on odd-numbered pixels, and the seventh group of nozzles # 134 to # 155. A group forms dots at even-numbered pixels.
As a result, the printer can form dots in the same dot formation order within the area printed by the overlap method.

(13) In the overlap method described above, the dot formation order of a plurality of raster lines sandwiched between two incomplete raster lines formed by one dot formation operation is normal printing (first printing process). This is the same in all areas where dots are formed.
As a result, it is possible to make the dot formation order in the area printed by normal printing and the dot formation order in the area printed by upper end printing (or lower end printing) all coincide.

(14) In the overlap method described above, the dot formation order by normal printing (first printing process) is the same as the dot formation order by upper end printing (second printing process). Thereby, for example, as shown in FIGS. 17A and 17C, the dot formation order can be made equal in all the print regions.
Thereby, the image quality of the print image by normal printing / upper end printing (or lower end printing) can be brought close to the same quality, and the image quality of the entire print image can be improved.

(15) The printer described above performs borderless printing on paper by normal printing (first printing process) and upper-end printing or lower-end printing (second printing process).
In top-end printing (or bottom-end printing) during borderless printing, the number of nozzles that can be used is reduced, and therefore the transport amount is reduced as compared with normal printing. If the carrying amount is different and the raster line formation order is changed, the image quality of normal printing and the image quality of upper end printing (or lower end printing) are different, and the image quality of the entire printed image is deteriorated.

In the above-described printer, since the order of forming raster lines for normal printing is the same as the order of forming raster lines for top-end printing (or bottom-end printing) in borderless printing, the image quality of the entire printed image is improved.
However, the borderless printing method is not limited to the above-described embodiment. For example, the platen may have a plurality of grooves, and the nozzles used for upper end printing may be different from the nozzles used for lower end printing.
Also, the improvement in image quality is not limited to borderless printing. For example, if printing is performed such that the carry amount changes during printing, the raster line formation order before and after changing the carry amount can be made equal to improve the image quality.

(16) Since the printer having all the above-described constituent elements has all the effects, it is possible to perform printing with higher image quality.

(17) A computer (printing control apparatus) in which the above-described printer driver is installed has a normal printing (first printing process) and top-end printing or bottom-end printing (second printing) on a printing apparatus including a transport unit and a carriage (moving body). Print processing). A plurality of raster lines formed by other dot forming operations are sandwiched between raster lines formed by one dot forming operation or unfinished raster lines (dot rows). It is assumed that the forming operation in the normal printing of the plurality of raster lines is equal to the forming order in the lower end printing. For example, according to the interlace method shown in FIG. 15, the three raster lines sandwiched between the two raster lines formed by the nozzle # 179 and the nozzle # 178 in normal printing are sequentially formed from the upstream side in the transport direction. The three raster lines sandwiched between the two raster lines formed by the nozzle # 101 and the nozzle 100 in the upper end printing (or lower end printing) are sequentially formed from the upstream side in the transport direction.
As a result, the image quality of the print image by the upper end printing (or the lower end print) approaches the image quality of the normal print image, and the image quality of the entire print image is improved.

(18) The printing method described above performs normal printing (first printing process) and upper-end printing or lower-end printing (second printing process). A plurality of raster lines formed by other dot forming operations are sandwiched between raster lines formed by one dot forming operation or unfinished raster lines (dot rows). It is assumed that the forming operation in the normal printing of the plurality of raster lines is equal to the forming order in the lower end printing.
As a result, the image quality of the print image by the upper end printing (or the lower end print) approaches the image quality of the normal print image, and the image quality of the entire print image is improved.

(19) The printer driver (program) described above executes normal printing (first printing process) and upper-end printing or lower-end printing (second printing process) on a printing apparatus including a transport unit and a carriage (moving body). Let A plurality of raster lines formed by other dot forming operations are sandwiched between raster lines formed by one dot forming operation or unfinished raster lines (dot rows). It is assumed that the forming operation in normal printing of a plurality of raster lines is the same as the forming order in bottom-end printing.
As a result, the image quality of the print image by the upper end printing (or the lower end print) approaches the image quality of the normal print image, and the image quality of the entire print image is improved.

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 is a schematic diagram of an overall configuration of a printer. 1 is a cross-sectional view of the overall configuration of a printer. It is a flowchart of the process at the time of printing. It is explanatory drawing which shows the arrangement | sequence of a nozzle. 9A and 9B are explanatory diagrams of the interlace method when the number of nozzles is eight. FIG. 10A is an explanatory diagram of an interlace method when the number of nozzles is 180. FIG. 10B is an explanatory diagram of the dot formation status of each region. FIG. 11A and FIG. 11B are explanatory diagrams of the overlap method when the number of nozzles is eight. FIG. 12A is an explanatory diagram of an overlap method when the number of nozzles is 180. FIG. 12B is an explanatory diagram of the dot formation status in each region. It is explanatory drawing of the ink discharge area | region at the time of borderless printing. FIG. 14A is an explanatory diagram when borderless printing is performed on the upper end portion of the paper. FIG. 14B is an explanatory diagram when printing the central portion of the paper. FIG. 14C is an explanatory diagram when borderless printing is performed on the lower end portion of the paper. FIG. 15A is an explanatory diagram of the dot formation order during normal printing. FIG. 15B is an explanatory diagram of the dot formation order during upper end printing in Comparative Example 1. FIG. 15C is an explanatory diagram of the dot formation order during upper-end printing according to the present embodiment. FIG. 16A is an explanatory diagram of the dot formation order during normal printing when k = 8. FIG. 16B is an explanatory diagram of a dot formation order during upper end printing in Comparative Example 2. FIG. 16C is an explanatory diagram of a dot formation order during upper-end printing according to the present embodiment. FIG. 17A is an explanatory diagram of the dot formation order during normal printing. FIG. 17B is an explanatory diagram of a dot formation order during upper end printing in Comparative Example 3. FIG. 17C is an explanatory diagram of a dot formation order during upper-end printing according to the present embodiment. FIG. 18A is an explanatory diagram of a dot formation order during upper end printing according to the present embodiment. FIG. 18B is an explanatory diagram of the dot formation order during upper end printing in Comparative Example 4. FIG. 19A is an explanatory diagram of dot formation in the region 2 by the above-described overlap method. FIG. 19B is an explanatory diagram of dot formation in the region 3 by the overlap method described above. FIG. 19C is an explanatory diagram of dot formation in the region 3 by the overlap method of the improved example. FIG. 20A is an explanatory diagram of dot formation in the overlap method. FIG. 20B is an explanatory diagram of dot formation of the overlap method of the improved example. FIG. 21 is an explanatory diagram of another interlace method.

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 controller, 61 interface unit, 62 CPU,
63 memory, 64 unit control circuit 100 printing system,
110 computers,
112 video drivers, 114 application programs,
116 printer driver 120 display device;
130 input device, 130A keyboard, 130B mouse,
140 recording / reproducing apparatus,
140A flexible disk drive device,
140B CD-ROM drive device

Claims (19)

A transport unit for transporting the medium in the transport direction;
A moving body that moves a plurality of nozzles arranged in the transport direction in the movement direction;
With
A first operation of repeating a transport operation in which the transport unit transports the medium by a predetermined transport amount and a dot forming operation in which ink is ejected from the plurality of moving nozzles to form a plurality of dot rows on the medium. Printing process,
A transport operation in which the transport unit transports the medium with a transport amount different from the predetermined transport amount, and a dot forming operation in which ink is ejected from the plurality of moving nozzles to form a plurality of dot rows on the medium. And a second printing process that repeats
A printing device for performing
In the first printing process and the second printing process, a plurality of dot rows formed by other dot forming operations are sandwiched between the dot rows formed by one dot forming operation. ,
The printing apparatus, wherein a formation order of the plurality of the dot rows sandwiched between the first print processes is equal to the formation order of the second print processes. The printing apparatus according to claim 1,
A printing apparatus, wherein dots are formed in pixels that are continuous in the movement direction by one dot forming operation. The printing apparatus according to claim 2,
D is an interval in the transport direction of dots formed on the medium,
The distance in the transport direction of the nozzles that eject the ink is k · D,
The number of nozzles that eject the ink in the first printing process is N1,
The number of nozzles that eject the ink in the second printing process is N2,
And when
N1 and k are relatively prime,
N2 and k are relatively prime,
A printing apparatus, wherein a remainder when N1 is divided by k is equal to a remainder when N2 is divided by k. The printing apparatus according to claim 3,
A printing apparatus characterized in that k has a prime relationship with a natural number smaller than k other than 1 or k-1. The printing apparatus according to claim 3 or 4, wherein
The printing apparatus according to claim 1, wherein the remainder is other than 1 or k-1. The printing apparatus according to any one of claims 2 to 5,
A printing apparatus, wherein the dot row is formed by the next dot forming operation without being adjacent to the dot row formed by the previous dot forming operation. The printing apparatus according to claim 1,
A printing apparatus, wherein dots are formed in pixels continuous in the movement direction by a plurality of dot forming operations. The printing apparatus according to claim 7, wherein
D is an interval in the transport direction of dots formed on the medium,
The distance in the transport direction of the nozzles that eject the ink is k · D,
The number of dot forming operations until a dot is formed on pixels that are continuous in the moving direction is M,
The number of nozzles that eject the ink in the first printing process is N1,
The number of nozzles that eject the ink in the second printing process is N2,
And when
N1 / M and k are relatively prime,
N2 / M and k are relatively prime,
A printing apparatus, wherein a remainder when N1 / M is divided by k is equal to a remainder when N2 / M is divided by k. The printing apparatus according to claim 8, wherein
A printing apparatus, wherein k has a prime relationship with a natural number smaller than k other than 1 or k-1. The printing apparatus according to claim 8 or 9, wherein
The printing apparatus, wherein the remainder is other than 1 or k. It is a printing apparatus in any one of Claims 7-10, Comprising:
A printing apparatus, wherein the dot row is formed by the next dot forming operation without being adjacent to the dot row formed by the previous dot forming operation. It is a printing apparatus in any one of Claims 7-11, Comprising:
In one dot forming operation, the position of a dot formed by a nozzle in the moving direction can be different from the position of a dot formed by another nozzle in the moving direction. Printing device to do. The printing apparatus according to any one of claims 7 to 12,
The printing apparatus is characterized in that the dot formation order of the plurality of dot rows sandwiched is the same in all regions where dots are formed by the first printing process. The printing apparatus according to claim 13,
A printing apparatus, wherein a dot formation order by the first printing process is equal to a dot formation order by the second printing process. The printing apparatus according to claim 1,
A printing apparatus that performs borderless printing on the medium by the first printing process and the second printing process. A transport unit for transporting the medium in the transport direction;
A moving body that moves a plurality of nozzles arranged in the transport direction in the movement direction;
With
A first operation of repeating a transport operation in which the transport unit transports the medium by a predetermined transport amount and a dot forming operation in which ink is ejected from the plurality of moving nozzles to form a plurality of dot rows on the medium. Printing process,
A transport operation in which the transport unit transports the medium with a transport amount different from the predetermined transport amount, and a dot forming operation in which ink is ejected from the plurality of moving nozzles to form a plurality of dot rows on the medium. And a second printing process that repeats
A printing device for performing
In the first printing process and the second printing process, a plurality of dot rows formed by other dot forming operations are sandwiched between the dot rows formed by one dot forming operation. ,
The formation order in the first printing process of the plurality of dot rows sandwiched between is equal to the formation order in the second printing process,
The interval in the transport direction of dots formed on the medium is D, the interval in the transport direction of the nozzles that eject the ink is k · D, and the dots until dots are formed in pixels that are continuous in the movement direction When the number of forming operations is M, the number of nozzles ejecting the ink in the first printing process is N1, and the number of nozzles ejecting the ink in the second printing process is N2,
N1 / M and k are relatively prime,
N2 / M and k are relatively prime,
The remainder when N1 / M is divided by k is equal to the remainder when N2 / M is divided by k,
k has a relatively prime natural number smaller than k other than 1 or k-1,
The remainder is other than 1 or k;
Form the dot row in the next dot formation operation without being adjacent to the dot row formed in the previous dot formation operation,
In one dot forming operation, it is possible to make the position in the movement direction of dots formed by a certain nozzle different from the position in the movement direction of dots formed by another nozzle,
The dot formation order of the plurality of dot rows sandwiched is the same in all regions where dots are formed by the first printing process,
The dot formation order by the first printing process is equal to the dot formation order by the second printing process,
A printing apparatus that performs borderless printing on the medium by the first printing process and the second printing process. A transport unit for transporting the medium in the transport direction;
A moving body that moves a plurality of nozzles arranged in the transport direction in the movement direction;
In a printing device equipped with
A first operation of repeating a transport operation in which the transport unit transports the medium by a predetermined transport amount and a dot forming operation in which ink is ejected from the plurality of moving nozzles to form a plurality of dot rows on the medium. Printing process,
A transport operation in which the transport unit transports the medium with a transport amount different from the predetermined transport amount, and a dot forming operation in which ink is ejected from the plurality of moving nozzles to form a plurality of dot rows on the medium. And a second printing process that repeats
A printing control device for performing
In the first printing process and the second printing process, a plurality of dot rows formed by other dot forming operations are sandwiched between the dot rows formed by one dot forming operation. ,
The printing control apparatus according to claim 1, wherein a forming order of the plurality of dot rows sandwiched between the first printing processes is equal to the forming order of the second printing processes. A first operation that repeats a transport operation for transporting a medium in a transport direction by a predetermined transport amount and a dot formation operation for ejecting ink from a plurality of nozzles moving in the movement direction to form a plurality of dot rows on the medium. Printing process,
A transport operation for transporting the medium in the transport direction by a transport amount different from the predetermined transport amount, and a plurality of dot rows are formed on the medium by ejecting ink from the plurality of nozzles moving in the movement direction. A second printing process that repeats the dot forming operation,
A printing method for performing
In the first printing process and the second printing process, a plurality of dot rows formed by other dot forming operations are sandwiched between the dot rows formed by one dot forming operation. ,
The printing method according to claim 1, wherein a formation order of the plurality of dot rows sandwiched in the first printing process is equal to the formation order in the second printing process. A transport unit for transporting the medium in the transport direction;
A moving body that moves a plurality of nozzles arranged in the transport direction in the movement direction;
A printing apparatus comprising:
A first operation of repeating a transport operation in which the transport unit transports the medium by a predetermined transport amount and a dot forming operation in which ink is ejected from the plurality of moving nozzles to form a plurality of dot rows on the medium. Printing process,
A transport operation in which the transport unit transports the medium with a transport amount different from the predetermined transport amount, and a dot forming operation in which ink is ejected from the plurality of moving nozzles to form a plurality of dot rows on the medium. And a second printing process that repeats
A program for executing
In the first printing process and the second printing process, a plurality of dot rows formed by other dot forming operations are sandwiched between the dot rows formed by one dot forming operation. ,
A program characterized in that the formation order in the first printing process of the plurality of dot rows sandwiched between is equal to the formation order in the second printing process.

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