JP2000318147A - Reconstitution for raster data when direction of scanning for recording raster is inverted - Google Patents

Abstract

PROBLEM TO BE SOLVED: To compensate for a positional deviation of dots and improve an image quality by arranging adjustment pixels for adjusting a position of an image pixel in a main scanning direction to both ends of the image pixel, and inverting the arrangement of the adjustment pixels when a direction of a path estimated for raster data is inverted during printing. SOLUTION: A printer 22 main scans to relatively reciprocate a printing head 28 to a printing medium, and at the same time, sends the printing medium in a sub scanning direction. During the time, the printer drives the printing head 28 according to printing data, thereby forming dots on at least part of a plurality of pixels arranged in a direction of the main scan, whereby images are formed. In forming dots at this time, image pixel value data showing a dot form state in image pixels includes raster data, sub scan feed data showing a feed amount in the sub scanning feed, and arrangement data of adjustment pixels not forming dots. Raster data having a path inverted is reconstituted by inverting an arrangement of adjustment pixels.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a printing apparatus and a printing method for printing an image by forming multicolor dots on a recording medium during main scanning.

[0002]

2. Description of the Related Art Conventionally, an ink jet printer has been used as an output device of an image processed by a computer or the like or an image captured by a digital camera. Ink jet printers, for example, cyan, magenta,
A dot is formed by discharging a plurality of colors of ink such as yellow and black. Usually, dots of each color are ejected from the print head while moving the print head in the main scanning direction.
At this time, if the formation positions of the dots of each color are shifted in the main scanning direction, there is a problem that the image quality is deteriorated.

[0003] The problem of image quality deterioration due to the deviation of the dot formation position occurs in both unidirectional printing and bidirectional printing. Here, the unidirectional printing means a printing method in which the dots are ejected only in one of the paths when the print head reciprocates along the main scanning direction. Also, bidirectional printing means a printing method in which the print head ejects dots in both forward and backward movements. In unidirectional printing, a positional deviation between dots of different colors usually poses a problem, whereas in bidirectional recording, a positional deviation in forward and backward movements of the same color also poses a problem.

[0004] In a conventional printer, the position of dots of other colors is adjusted in the main scanning direction with reference to, for example, a black dot to reduce the positional deviation of the dots. In addition, such adjustment of the displacement has been realized by a head drive circuit that supplies a drive signal to the print head, changing the output timing of the drive signal.

[0005]

However, the above-described conventional position shift adjusting method has various restrictions caused by this method. For example, in a normal printer, the timing of the drive signal can only be changed for the entire print head,
The adjustment of the dot displacement has also been limited to the one that can be realized by this timing change.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems in the prior art, and the head drive circuit utilizes means other than changing the output timing of the drive signal in the main scanning direction of dots. It is an object of the present invention to provide a technique for reducing positional deviation and thereby improving image quality.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, according to the present invention, a head having a plurality of nozzles for discharging ink is reciprocated relative to a print medium in a predetermined direction. While performing moving main scanning, a sub-scan is performed to relatively send the print medium in a sub-scanning direction intersecting the main scanning direction with respect to the head, and the head is moved in accordance with the print data in at least one of the reciprocating paths. Drive,
A dot is formed on at least a part of the plurality of pixels arranged in the main scanning direction. At that time, when forming dots in accordance with the print data, image pixel value data representing the dot formation state in the image pixels forming the image and dots used to adjust the position of the image pixels in the main scanning direction are used. By using the adjustment pixel value data indicating the presence of the adjustment pixel not to be formed, the deviation of the dot formation position of each nozzle in the main scanning direction is compensated. In the following, various aspects of the invention will be described.

(1) Distribution of adjustment pixels to one end and the other end in the main scanning direction: First, the adjustment pixels are allocated to one end and the other end of the image pixel value data so as to compensate for the shift amount of the dot formation position. Set the distribution. Here, regarding “distribution of the adjustment pixels to one end and the other end”, there is a case where the adjustment pixels are not arranged in one of them. Raster data having image pixel value data and adjustment pixel value data arranged on at least one of both ends of the image pixel value data is generated from the image pixel value data and the set adjustment pixel distribution.
Then, print data including raster data is generated. Thereafter, the head is driven according to the print data while performing main scanning.

According to this aspect, by providing the following characteristics to the print data when driving the head, it is possible to compensate for a shift in the dot formation position, and to realize high quality printing. Can be. Normally, as print data for driving the head, data obtained by converting the gradation value of an image into multi-level data for each pixel arranged in a predetermined number is used. Such data corresponds to image pixel data in the present invention. The print data of the present invention has a predetermined number of adjustment pixels in the main scanning direction in addition to the image pixel data. The adjustment pixel is data corresponding to a margin in the main scanning direction.

By using the print data having such a structure, the printing apparatus of the present invention can compensate for a shift in the dot formation position within the range of the adjustment pixels. A case where main scanning is performed in the left and right directions will be described as an example. Consider a case where there is a nozzle whose dot formation position is formed on the left side of the original pixel due to the ink ejection characteristics and the like. In the printing apparatus of the present invention, the shift amount of the dot formation position by the nozzle is stored in advance. Here, it is assumed that the shift amount corresponds to one pixel. In the present invention, print data is generated by shifting the positions of dots formed by the nozzles according to the stored shift amount. That is, print data for forming a dot at a position shifted to the right by one pixel from the original pixel is generated. This means that the number of adjustment pixels on the right side is reduced by one pixel compared to the case where dots can be formed at appropriate positions, and the distribution of adjustment pixels in the main scanning direction is set with the number of adjustment pixels on the left side increased by one pixel. Is equivalent to When ink is ejected from these nozzles based on such print data, the above-described shift occurs, and as a result, dots are formed in pixels that should be formed.

According to the printing apparatus of the present invention, it is possible to compensate for the deviation of the dot formation position in pixel units based on the above principle. In recent years, since the resolution of the printing apparatus has been extremely high, the width of each pixel in the main scanning direction is very short. Can compensate. Therefore, according to the printing apparatus of the present invention, high-quality printing can be realized. Further, according to the present invention, since the above-mentioned compensation can be performed without requiring new hardware for the driving mechanism of the head, it is possible to relatively easily reduce the deviation of the dot formation position.

In the present invention, print data can be generated through various steps. For example, as a first step:
Regardless of the displacement amount of the formation position, basic data in which a predetermined number of adjustment pixels are arranged on both sides of the image pixels in the main scanning direction is generated. As a second stage, the image may be generated in two stages of shifting the position of the image pixel according to the shift amount of the formation position, that is, changing the distribution of the adjustment pixels located on both sides. <BR>

As a first step, the distribution of the adjustment pixels located on both sides is set according to the amount of displacement of the formation position.
The print data may be generated in a second step of adding adjustment pixels at a distribution set on both sides of the image pixels.

In the printing apparatus according to the present invention, the predetermined number of the adjustment pixels may be set to an appropriate value within a range where the displacement of the formation position can be compensated. One pixel or a plurality of pixels may be used.

In the present invention, the distribution of the adjustment pixels according to the deviation of the dot formation position can be performed individually for each nozzle. When forming color dots, it is preferable to set the distribution for each ink color.

In such an embodiment, the displacement of the forming position is compensated for each color. In general, the head of a printing apparatus often has substantially the same characteristics regarding the dot formation position for each color due to the manufacturing process and the viscosity of the ink. Therefore, according to the above-described configuration, it is possible to relatively easily compensate for the displacement of the formation position. In addition, when the deviation of the dot formation position occurs between different colors, it greatly affects the image quality. According to the above configuration, the shift between colors can be easily suppressed, so that the effect of improving the image quality is great.

In the case where dots are formed by using nozzles that are divided into a plurality of nozzle rows extending in the sub-scanning direction and that are arranged along the main scanning direction, Is preferably set for each nozzle row. The head may have substantially the same formation position characteristics for each nozzle row. In such a case, the image quality can be relatively easily improved by compensating the displacement of the formation position for each nozzle row.

In the case where the image pixel value data is two-dimensional image data representing pixels arranged two-dimensionally in the main scanning direction and the sub-scanning direction, when the adjustment pixels are distributed, Is preferable. That is, the correspondence between each nozzle provided in the head and the two-dimensional image data is determined according to the sub-scan feed amount. Then, the distribution of the adjustment pixels is set according to the determination.

According to such a mode, it is possible to determine which nozzle in the print data forms each pixel, that is, pixels arranged in the main scanning direction. And
The displacement of the forming position can be compensated based on the determination result. As a result, the deviation of the dot formation position can be appropriately compensated for each nozzle, and the printed image quality can be greatly improved. In a printing apparatus with sub-scanning, it is usual that print data is supplied to the head after determining the correspondence between rasters and nozzles. The necessary determination means can be applied as it is.

In printing with sub-scanning, print data can be generated in various processes. For example, as the first stage, print data in which a predetermined number of adjustment pixels are arranged on both sides regardless of the correspondence with the nozzles is generated. As the second step, print data can be generated in two steps of determining the correspondence with the nozzles and correcting the distribution of the adjustment pixels. Of course, only the data of the image pixels may be prepared in the first stage, and the adjustment pixels may be added in the second stage.

In the first stage, the correspondence between each raster and the nozzle is determined, and the distribution of adjustment pixels is set. As a second step, print data may be generated by adding adjustment pixels in a distribution set for image pixels.

It is desirable to drive the head in both reciprocating paths in the main scanning. Generally, when dots are formed on both reciprocating paths in main scanning,
That is, when performing bidirectional recording, the displacement of the formation position increases. For example, a case will be described in which dots are formed while moving from left to right during forward movement, and dots are formed while moving from right to left during backward movement. Assume that there is a nozzle in which the dot formation position is shifted by one pixel to the left of the original pixel during the forward movement. When the nozzle moves backward, the dot formation position is shifted to the right by one pixel. As a result, there is a relative displacement of two pixels between the dots formed during the forward movement and the dots formed during the backward movement.
As described above, in the bidirectional printing, the shift of the dot formation position has a large effect on the image quality. Therefore, if the present invention is applied to a printing apparatus that performs bidirectional printing, such a shift in the formation position can be suppressed, and the effect of improving image quality is very large.

It should be noted that the head can be driven on one of the outward path and the return path. In such an embodiment,
It is possible to avoid the problem of dot formation position shift due to the difference in the scanning direction.

In the printing of dots, it is preferable that the printing of dots on each main scanning line be completed on one path of the head. According to such an aspect, since each raster is formed by a single nozzle, it is possible to relatively easily and accurately compensate for a shift in the formation position. As a technology to form each raster by dividing it with multiple nozzles,
There is a so-called overlap recording. In the overlap method, for example, an odd-numbered pixel of a raster is recorded by a first nozzle, and then an even-numbered pixel is recorded by a second nozzle with a sub-scan being interposed therebetween. When performing such printing, two nozzles having different characteristics related to the formation position form one raster. Therefore, the operation for compensating the displacement of the forming position becomes very complicated. In contrast,
When each raster is formed by a single nozzle, the distribution of adjustment pixels can be uniquely set for each raster, and the displacement of the formation position can be compensated relatively easily. However, this does not mean that the present invention cannot be applied to the aurabop method.

In the present invention, it is not always necessary to compensate for a shift for the entire image data. The shift may be compensated only in an area where the shift of the dot greatly affects the image quality. For example, for ink of a color having relatively low visibility, compensation for deviation may be omitted. Further, the shift may be compensated only in an area where the dot shift greatly affects the image quality, such as an area where dots are formed at an intermediate recording density. If the deviation is compensated only when the deviation of the dot greatly affects the image quality, the processing load at the time of printing can be reduced and the processing speed can be improved.

Further, a predetermined test pattern set so as to detect the shift amount of the dot formation position of each nozzle can be printed, and the shift amount of the dot formation position can be specified based on the test pattern. .

The displacement of the dot formation position is caused by various factors such as the ink ejection characteristics of each nozzle, backlash when the head reciprocates, and changes in the viscosity of the ink. As described above, the deviation of the dot formation position may occur after the shipment. According to the above aspect,
A test pattern can be printed, and the shift amount can be set based on the test pattern. Therefore, even if the dot formation position shifts after shipping, the user can relatively easily reset the stored shift amount.
As a result, high-quality printing can be relatively easily maintained, and the convenience of the printing apparatus can be improved.

Various methods can be used for setting the shift amount based on the test pattern. For example, the deviation amount can be set by printing a test pattern in which dots are formed at various preset timings and selecting a timing at which the dot formation position is in the most preferable state.

(2) Inversion of Arrangement of Adjusted Pixels When a Predetermined Event Occurs: The present invention can also take the following forms. That is, first, print data including raster data, sub-scan feed data, and adjustment pixel arrangement data is generated. Here, the raster data is data having at least image pixel value data for each nozzle of each main scan. The sub-scan feed data is data representing the feed amount of the sub-scan feed performed after each main scan. The adjustment pixel arrangement data is configured as data different from the raster data, indicates the arrangement number of the adjustment pixels at both ends of the image pixel value data, and is data that functions as at least a part of the adjustment pixel value data. Thereafter, the head is driven in accordance with the print data in both the reciprocating paths to form dots.
Further, when the direction of the path scheduled for each raster data is reversed, it is detected. Then, for the raster data whose path is reversed, the arrangement of the adjustment pixels is reversed with the image pixels interposed therebetween, and the adjustment pixel value data is arranged on at least one of both ends of the image pixel value data according to the arrangement of the reversed adjustment pixels. Reconstruct raster data.

According to this aspect, it is possible to appropriately correct the dot recording position deviation even for raster data to be recorded in the direction opposite to the direction of the previously assigned path. .

The raster data may include, as at least a part of the adjustment pixel value data, adjustment pixel data of the same format as the image pixel value data. According to this aspect, the printing unit that receives the print data can handle the image pixel value data and the adjustment pixel data collectively as pixel data, and the processing is simplified.

Preferably, the raster data is provided with a reciprocating flag indicating the direction of the route scheduled for each raster data. With this mode, the printing unit side
It is possible to know which scan each raster data is assumed to be used in.

In the case where a step of ejecting a predetermined color ink for each nozzle to form multicolor dots is included, the number of adjustment pixels arranged in the adjustment pixel arrangement data is independently determined for each ink color. It is preferable to determine. With such an embodiment, the dot formation position can be corrected by reflecting the characteristics of each ink.

In the case where dots are formed by using nozzles that are divided into a plurality of nozzle rows each extending in the sub-scanning direction and that are arranged along the main scanning direction, It is preferable that the number of arranged adjustment pixels in the pixel arrangement data is determined independently for each nozzle row. Since each nozzle in the nozzle row may have common characteristics, such a mode can appropriately correct the deviation of the dot formation position.

Further, it is preferable that the number of adjustment pixels arranged in the adjustment pixel arrangement data is determined independently for each nozzle.
According to such an embodiment, since the dot formation position deviation can be corrected for each nozzle, the quality of the printing result can be improved.

(3) Forming dots using a plurality of original drive signals: Printing may be performed as follows. That is,
First, the nozzle generates a plurality of original drive signals in which signals for recording one pixel are repeated. Here, the plurality of original drive signals are a plurality of original drive signals having the same cycle and being out of phase. Then, a drive signal for driving a drive device provided for each nozzle to eject ink is generated from the original drive signal to form dots. In such a case, the following is preferable. That is, when generating print data, image pixels and adjustment pixels arranged side by side on each main scan line are divided into a plurality of pixel groups. Then, dots on each pixel of the plurality of pixel groups are formed according to different original drive signals.

According to such an embodiment, dots can be recorded in high-density pixels as compared with the case where dots are formed by one original drive signal. Further, even if the arrangement of the adjustment pixels is changed according to the deviation of the dot formation position, it is possible to record the dots by reflecting the change.

Further, a plurality of original drive signals are sequentially shifted in phase by 1 / N (N is a natural number of 2 or more) of one cycle.
When the number of original drive signals is N, the number of pixel groups is preferably N. According to such an embodiment, dots can be recorded in N times higher density pixels than when dots are formed by one original drive signal. Further, since the original drive signals are evenly shifted in phase, it is possible to record an image with pixels having a uniform density.

In dividing the pixels into pixel groups, it is preferable that the image pixels and the adjustment pixels arranged side by side on the main scanning line be classified into the same pixel group in the order of arrangement in N cycles. . With such an embodiment, high-quality printing can be performed by simple and regular processing.

It is preferable to drive the head in both the reciprocating paths in the main scanning. By doing so, the time required for printing can be reduced. Also,
The head can also be driven on one of the outward path and the return path. By doing so, it is possible to avoid the problem of the deviation of the dot formation position caused by the difference in the main scanning direction.

(4) Offset Adjustment with Compensation of the Interval Between Nozzle Rows: The nozzles are divided into a plurality of nozzle rows each extending in the sub-scanning direction, and the plurality of nozzle rows are predetermined along the main scanning direction. When the nozzles are arranged with an interval of, the delay data representing the amount of delay for compensating for the difference in the arrival times at the pixels in the main scan in accordance with the design distance of the nozzles in the main scan direction is calculated. May be used. In such a case, the following is preferable. That is, first, the delay data is readjusted so as to compensate for the shift amount of the dot formation position. Then, for each nozzle of each main scan, using the readjusted delay data as adjustment pixel value data, readjusted delay data;
Then, serial data including image pixel value data arranged following the delay data is generated. Thereafter, dots are formed based on the serial data. According to such an embodiment, it is possible to effectively compensate for the dot formation position deviation by effectively utilizing the delay data for compensating the interval between the nozzles in the main scanning direction.

In forming the dots, the nozzle is set at 1
In some cases, an original drive signal in which a signal for recording a pixel is repeated is generated, and a drive signal for driving a driving device provided for each nozzle to eject ink is generated from the original drive signal. In such a case, the following is preferable. That is, the delay data is provided in units of one cycle of the original drive signal. Then, the delay data is readjusted in units of one cycle of the original drive signal based on the shift amount. In addition, a drive signal is generated from the serial data for each nozzle and the original drive signal. According to such an embodiment, it is possible to adjust the delay data in units of the number of drive signals and correct the deviation of the dot formation position.

The nozzle rows arranged in the main scanning direction are:
It is preferable that the pixels are arranged at intervals of m times (m is a natural number of 1 or more) the pixel pitch corresponding to the printing resolution along the main scanning direction. For such a nozzle, the dot displacement caused by the interval between the nozzles can be effectively eliminated by the delay data provided in one cycle unit of the original drive signal.

Further, when generating the original drive signals, N original drive signals having the same period and being sequentially shifted in phase by 1 / N of one period are generated, and each of the original drive signals is assigned to a corresponding nozzle. It may be supplied to a group of drives. In such a case, the following is preferable. That is, the plurality of nozzles are N sets (N is a natural number of 2 or more)
Nozzle group. Then, a drive signal is generated from the serial data for each nozzle and the original drive signal supplied to the drive device for each nozzle. According to such an embodiment, dots can be recorded in N times higher density pixels than when dots are formed by one original drive signal. Further, after allocating the image pixels to the respective original drive signals, it is possible to perform a process for compensating for a dot formation position shift. Therefore, compared with the case where the data of the pixel after the compensation is assigned to each original drive signal, it is possible to compensate for the dot formation position shift by handling a small amount of data.

In the above aspect, the nozzle array arranged in the main scanning direction has an interval of N · m times (m is a natural number of 1 or more) the pixel pitch corresponding to the printing resolution along the main scanning direction. It is preferable that they are arranged with an interval. Regarding such nozzles, even in printing in which high-density dots are recorded by using a plurality of original drive signals, the intervals between the nozzles are caused by delay data provided in units of one cycle of the original drive signals. It is possible to effectively eliminate dot misalignment.

It is preferable to drive the head in both the reciprocating paths in the main scanning. By doing so, the time required for printing can be reduced. Also,
The head can also be driven on one of the outward path and the return path. By doing so, it is possible to avoid the problem of the deviation of the dot formation position caused by the difference in the main scanning direction.

The present invention can be implemented in various modes as described below. (1) Printing device. Print control device. (2) Printing method. Print control method. (3) Computer programs for realizing the above devices and methods. (4) A recording medium on which a computer program for realizing the above apparatus and method is recorded. (5) A data signal embodied in a carrier wave including a computer program for realizing the above apparatus and method.

[0048]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Here, embodiments of the present invention will be described in the following order. (1) Configuration of the device: (2) Dot forming process in unidirectional printing: (3) Distribution of adjustment pixels for each nozzle: (4) First embodiment: (5) Second embodiment: (6) Second Third embodiment: (7) Fourth embodiment:

(1) Apparatus Configuration: FIG. 1 is an explanatory diagram showing a schematic configuration of a printing apparatus as an embodiment. The printing apparatus of this embodiment is configured by connecting a printer PRT to a computer PC by a cable CB. The computer PC transfers the data for printing to the printer PRT,
It plays a role in controlling the operation of the printer PRT. These processes are performed based on a program called a printer driver.

The computer PC can load and execute a program from a recording medium such as a flexible disk or a CD-ROM via a flexible disk drive FDD or a CD-ROM drive CDD. The computer PC is connected to an external network TN, and can access a specific server SV to download a program. As a matter of course, these programs may adopt a mode in which the entire program necessary for printing is loaded collectively, or a mode in which only some modules are loaded.

FIG. 2 is an explanatory diagram showing functional blocks of the printing apparatus. In the computer PC, an application program 95 is executed under a predetermined operating system.
Is working. A printer driver 96 is incorporated in the operating system. The application program 95 performs processing such as generation of image data. Then, the printer driver 96 generates print data from the image data. That is, it can be said that the printer driver 96 functions as the raster data generation unit in the claimed invention.

The printer driver 96 includes an input unit 10
0, color correction processing unit 101 and color correction table LUT,
Halftone processing unit 102, print data generation unit (raster data generation unit) 103, and adjustment data distribution table A
Each functional unit of T and the output unit 104 is prepared. In a narrow sense, there is a case where the print data generation unit 103 is interpreted as the print data generation unit in the claimed invention.

When a print command is issued from the application program 95, the input unit 100 receives and temporarily stores the image data. The input unit 100 corresponds to an image pixel value data storage unit in the claimed invention.
The color correction processing unit 101 converts the color components of the image data into a printer P
A color correction process for correcting a color component corresponding to the RT ink is performed. In the color correction process, the color components of the image data are
This is performed by referring to a color correction table LUT that stores in advance a correspondence relationship with color components that can be expressed by T ink. The halftone processing unit 102 performs a halftone process on the data that has been subjected to the color correction process in order to express the tone value of each pixel in the dot recording density. The adjustment pixel number setting unit 10 included in the print data generation unit 103
Numeral 8 generates print data capable of compensating for a shift in dot formation position by adding adjustment pixel data to the halftone-processed data. This adjustment pixel number setting unit 108 corresponds to the distribution setting unit of the claimed invention. The distribution of the adjustment pixel data is set with reference to the discharge characteristic data stored in the discharge characteristic data storage (shift amount storage) 114 on the printer PRT side, and is stored in the adjustment data distribution table AT. Then, the print data generation unit 103 converts the image data to which the adjustment pixel data has been added in the order in which the image data is recorded by the printing apparatus, that is,
The print data is rearranged in the order of the paths in the printing apparatus, and predetermined information such as the resolution of the image is added to generate print data. Here, "pass" means one main scan in which dots are formed. The print data thus generated is output to the printer PRT by the output unit 104. Thereafter, the print data is converted and processed into various forms up to an electric signal for actually driving the machine, and printing is performed. Here, the term “print data” means data generated by the print data generation unit 103 in a narrow sense, but also data at a stage after being converted and processed into various forms in a broad sense. I do.

The printer PRT includes an input unit 110, a reception buffer 115, a development buffer 44, a register 117,
Main scanning unit 111, sub-scanning unit 112, and head driving unit 1
Thirteen functional units are provided. These components are controlled by the CPU 41. This printer PRT functions as a printing unit in the claimed invention.

In the printer PRT, the printer driver 9
The input unit 110 receives the print data transferred from the printer 6 and temporarily stores the print data in the reception buffer 115. Then, data for one pass from the data stored in the reception buffer 115 is sequentially sent to the expansion buffer 44. This data stores dot formation information for one pass for all nozzles used in one main scan. That is, the data sent to the development buffer 44 stores pixel value data for a plurality of raster lines on which dots are printed in one main scan. Then, dot formation information for one pixel of each nozzle is collectively extracted from the dot formation information for one pass of the nozzles in the order in which each nozzle forms dots, and sent to the register 117. That is, from the dot formation information on a plurality of raster lines, dot formation information on pixels arranged in a direction intersecting the raster lines (sub-scanning direction, row direction) is cut out in parallel, and is sequentially sent to the register 117. The register 117 converts the cut data into serial data and sends it to the head driving unit 113.
Then, the head driving unit 113 drives the head according to the serial data to print an image. On the other hand, from the data for one pass in the expansion buffer 44, data indicating the main scan sending method and data indicating the sub-scan sending method are also extracted and sent to the main scanning unit 111 and the sub-scanning unit 112. Then, the main scanning unit 111 and the sub-scanning unit 112
The main scanning of the head and the conveyance of the printing paper are performed according to the data. The functions of the above-described units of the printer PRT are specifically described by C
PU41, PROM42, RAM43, expansion buffer 4
4 etc. are fulfilled.

The schematic structure of the mechanical part of the printer PRT will be described with reference to FIG. As shown, the printer PRT
Is a circuit for transporting the paper P by the paper feed motor 23, a circuit for reciprocating the carriage 31 in the axial direction of the platen 26 by the carriage motor 24, and driving a print head 28 mounted on the carriage 31 to eject ink. And a circuit for forming dots, and a control circuit 40 for controlling the exchange of signals with the paper feed motor 23, the carriage motor 24, the print head 28 and the operation panel 32.
It is composed of

The circuit for reciprocating the carriage 31 in the axial direction of the platen 26 includes a sliding shaft 34 laid parallel to the axis of the platen 26 and holding the carriage 31 slidably.
A pulley 38 for extending an endless drive belt 36 between the carriage motor 24 and a position detection sensor 39 for detecting the origin position of the carriage 31 are provided.

The carriage 31 of the printer PRT has a cartridge 71 for black ink (K) and a cartridge 72 for color ink containing three color inks of cyan (C), magenta (M) and yellow (Y). Can be mounted. A total of four actuators 61 to 64 are formed on the print head 28 below the carriage 31.

FIG. 4 is an explanatory diagram showing the arrangement of the nozzles Nz in the actuators 61 to 64. The arrangement of these nozzles consists of four sets of nozzle arrays that eject ink for each color. Each nozzle array is composed of 48 nozzles Nz arranged in a staggered manner at a constant nozzle pitch. That is, each nozzle array is composed of two nozzle rows extending in the sub-scanning direction, and the nozzles constituting each nozzle row are alternately arranged in the sub-scanning direction. The nozzle arrays are arranged side by side in the main scanning direction, and the positions of the nozzle arrays in the sub scanning direction coincide with each other.

FIG. 5 is an explanatory diagram showing the structure of the piezo element PE and the nozzle Nz in detail. Each nozzle is provided with an ink passage 68 for supplying ink from the ink cartridges 71 and 72. Further, a piezo element (driving device) PE is disposed adjacent to the ink passage 68. When the control circuit 40 applies a predetermined drive voltage to the piezo element PE, the ink path 68 is deformed by the distortion of the piezo element PE, and the ink Ip is ejected.

The control circuit 40 (see FIG. 3) has a CP
It is configured as a microcomputer including a U41, a PROM 42, a RAM 43 and the like. Further, there are provided a transmitter for periodically outputting a drive voltage for driving the print head 28, and a development buffer 44 for storing information on / off of dots for each pixel for each nozzle Nz. When the data stored in the development buffer 44 is sequentially output to the print head 28 when performing main scanning, ink is ejected from each nozzle to each pixel according to the data.

Although the present embodiment employs a mechanism for ejecting ink using piezo elements, a printer which ejects ink by another method may be used. For example, the present invention may be applied to a printer of a type in which a heater disposed in an ink passage is energized and ink is ejected by bubbles generated in the ink passage.

(2) Dot Forming Process in Unidirectional Printing: First, a control process for correcting a dot displacement in unidirectional printing will be described. FIG. 6 shows the printer P
FIG. 4 is an explanatory diagram illustrating a state of a pixel printed by an RT. As shown in the drawing, on the printing paper P, dots are respectively formed on pixels arranged two-dimensionally in the main scanning direction and the sub-scanning direction. In the present invention, two types of pixels, image pixels and adjustment pixels, are used. As shown in the figure, image pixels are arranged at the center in the paper main scanning direction, and adjustment pixels are arranged at both ends. Dots for reproducing the image received from the application program 95 are formed on the image pixels. For this reason, the image pixels are two-dimensionally arranged in the main scanning direction and the sub-scanning direction to form two-dimensional image data. The adjustment pixels are pixels used to adjust the printing position of the image in the main scanning direction according to the shift of the dot formation position, as described later.

FIG. 7 is a flowchart of a print data generation processing routine. This process is a process executed by the printer driver 96 (see FIG. 2) in the computer PC. When this process is started, image data is input to the input unit 100 (see FIG. 2) (Step S10). The image data input here is data passed from the application program 95 shown in FIG.
It is data having 256 gradation values of values 0 to 255 for each color of R, G, and B for each pixel constituting the image. The resolution of the image data changes according to the resolution of the original image data ORG and the like.

The color correction processing section 10 of the printer driver 96
1 (see FIG. 2) performs a color correction process on the input image data (step S20). R, G, B color correction processing
This is a process of converting the image data having the gradation values of the above into gradation value data for each ink used in the printer PRT.
This process is performed using the color correction table LUT (see FIG. 2). Various well-known techniques can be applied to the processing itself for performing color correction using the color correction table, and for example, processing by interpolation calculation can be applied.

When the color correction processing is completed, the halftone processing section 102 (see FIG. 2) performs halftone processing for each ink (step S30). The halftone process means that the gradation value of the original image data (here, 256 gradations)
N bits (n) indicating the state of dot formation on each pixel
Is a natural number) image pixel value data.
The halftone processing can be performed by various known methods such as an error diffusion method and a dither method.

When the halftone process is completed, the adjustment pixel number setting unit 108 (see FIG. 2) included in the print data generation unit 103 sets the distribution of the adjustment pixels according to the following process (step S40). FIG. 8 is an explanatory diagram showing a state of dots formed at appropriate timing. The squares in the figure indicate pixels that are two-dimensionally arranged on the paper P. The numbers 1 to 10 are numbers for convenience to represent the position in the main scanning direction. As shown in the drawing, when the carriage ejects ink at a predetermined timing while moving in the main scanning direction, dots can be formed in the fifth row.

FIG. 9 is an explanatory view showing the state of dots formed by nozzles in which the formation positions are shifted. Originally, even if ink is ejected at a timing at which dots can be formed in the fifth pixel, the dot formation position may shift in the main scanning direction depending on the ink ejection characteristics of each nozzle. Here, a state in which dots are formed shifted to the left side in the main scanning direction is illustrated. As a result, a dot which should fly and be formed in the direction shown by the broken line in the drawing is formed in the fourth pixel.

FIG. 10 is an explanatory diagram showing a state in which the shift of the dot formation position is compensated by adjusting the image data. As shown in FIG. 9, consider the case where dots are formed shifted to the left from the original pixels. That is, when ink is ejected at the timing Ta for forming a dot on the fifth pixel, a case is considered in which a dot is formed shifted to the fourth pixel as shown by the broken line in the figure. In this case, the image data is adjusted, and the ink is ejected at timing Tb for forming a dot on the sixth pixel. If the ink ejection characteristics are appropriate and the ink is ejected at the timing Tb, a dot is formed at the sixth pixel as shown by the dashed line in the figure. However, since the dots actually have the characteristic of being shifted, the ink flies in the direction indicated by the solid line, and the dots are formed in the fifth pixel. That is, by adjusting the image data in consideration of the shift amount, it is possible to form a dot at a pixel to be originally formed. The setting of the distribution of the adjustment pixels is performed based on the above principle in order to compensate for the deviation of the dot formation position.

FIG. 11 is an explanatory diagram showing a state in which the deviation of the dot formation position is compensated by setting the distribution of the adjustment pixels.
The squares in the figure indicate the state of print data (hereinafter, referred to as “raster data”) corresponding to one raster. Pixels numbered 1 to 10 in the figure are image pixels. The pixels A1 to A4 arranged at both ends are adjustment pixels.
Here, a case where two adjustment pixels are provided at both ends is shown. Image pixel value data halftoned according to the image data is assigned to the image pixels. Adjustment pixel value data having a value indicating a dot non-formation state is assigned to the adjustment pixel.

The upper part of FIG. 11 shows the raster data before setting the distribution of the adjustment pixels. The circle of the fifth pixel corresponds to the example of FIGS. 8 to 10 and means that a dot is formed at the fifth pixel. If the dot formation position is correct, printing is performed based on such data, thereby forming a dot at the fifth pixel. The lower part of FIG. 11 shows data when the adjustment corresponding to FIGS. 9 and 10 is performed. As described above, for a nozzle having the characteristic that the dot formation position is shifted by one pixel to the left, the dot that should be originally formed in the fifth pixel is shifted to the right by one pixel. The raster data may be changed so as to form the raster data. That is, as shown in FIG. 11, the entire raster data may be shifted rightward by one pixel. This state corresponds to a state in which the distribution of the adjustment pixels originally distributed by two pixels on both sides is changed to three pixels on the left side and one pixel on the right side. When printing is performed based on such raster data, dots are formed at positions where they should be formed as shown in FIG.

The number of adjustment pixels to be distributed to the left and right is set according to the shift of the dot formation position of each nozzle. The deviation of the formation position of each nozzle is stored in the printer PRT as ejection characteristic data. FIG. 12 is an explanatory diagram showing an example of the ejection characteristic data. Here, a table for providing a shift amount for each ink is prepared. The amount of shift in the dot formation position due to the difference in the ink ejection characteristics is almost the same for different nozzles as long as the ink is the same. In addition, deviation of the dot formation position between colors has a large effect on image quality. From this point of view, in the example of FIG. 12, the deviation of the dot formation position is uniformly compensated for each color, not for each nozzle.

As shown in the drawing, the ejection characteristic data stores a value representing the shift amount of the dot formation position for each color in pixel units. For example, for black (K), a value -1 meaning that a dot is formed at a position shifted by one pixel from the original pixel in a direction opposite to the moving direction of the carriage.
Is stored. That is, black (K) has the ink ejection characteristics shown in FIGS. For cyan (C), a value -2, which means that a dot is formed at a position shifted by two pixels in the opposite direction to the moving direction of the carriage, is stored. Magenta (M) stores a value of 1 which means that dots are formed with a shift of one pixel in the moving direction of the carriage. Yellow (Y)
Is a value of 0, which means that there is no shift in the dot formation position. Of course, these values are
A value corresponding to the discharge characteristics of the RT is stored.

The flowchart of FIG. 7 shows that the distribution of the adjustment pixels is set during the print data generation processing. Actually, when the printer driver 96 is activated, the CPU of the computer PC reads the table of the shift amount stored in the printer PRT (see FIG. 12) and adjusts the adjustment data distribution in which the distribution of the adjustment pixels is set for each color. Set up the table. FIG. 13 is an explanatory diagram showing an example of the adjustment data distribution table. 13 shows a table corresponding to the ejection characteristic data of FIG. Here, a case in which adjustment pixels for a total of four pixels are distributed according to the example of FIG. 11 is illustrated. As described earlier with reference to FIG. 11, in order to compensate for the shift in the dot formation position for black (K), the adjustment pixel
Pixels are allocated one pixel to the right. Based on the same concept, in cyan (C), 4 pixels are allocated to the left side and 0 pixels are allocated to the right side. In magenta (M), one pixel on the left and 3 on the right
Pixels are allocated. In the yellow (Y), since dots are formed at appropriate positions, two pixels are equally distributed to the left and right. The number of adjustment pixels is not limited to four pixels, and can be set arbitrarily within a range where the deviation of the dot formation position can be compensated. In step S40, the adjustment data distribution table thus set is read to set the distribution of the adjustment pixels for each color.

When the distribution of the adjustment pixels is set in this way,
As shown in FIG. 7, the print data generation unit 103 (see FIG. 2) rasterizes the image pixel value data to generate raster data as shown in the lower part of FIG. 11 (Step S).
50). Rasterization refers to a process of rearranging halftone-processed image pixel value data in an order in which the pixel data is transferred to the printer PRT. In this process, the adjustment pixel and the halftone-processed image pixel value data are merged. For example, in a case where three adjustment pixels are provided on the left side and one adjustment pixel is provided on the right side, first, as shown in FIG. Pixels are arranged, data corresponding to the halftone-processed image data is arranged in the moving direction of the carriage, and finally, data for one pixel corresponding to the adjustment pixel located on the right side is arranged. . Data obtained by fusing the adjusted pixels and the image pixels subjected to the halftone processing in this way is referred to as raster data. The print data supplied to the printer PRT includes the raster data and data indicating the sub-scan feed amount.

The output unit 104 (see FIG. 2) outputs the print data thus created to the printer PRT (Step S60). The above processing is executed for all rasters (step S70). Control circuit 4 of printer PRT
0 prints an image by forming dots while performing main scanning according to the transferred print data.

In the above description, the data of the halftone-processed image pixel is once generated (step S3).
0), it has been described that print data is generated by fusing the separately adjusted distribution pixels. On the other hand, print data may be generated in the following order. First, halftone processing is performed, and first print data is generated in a state where predetermined adjustment pixels are arranged on the left and right. Adjustment pixels are arranged in a number corresponding to a case where dots are formed at appropriate positions. This data corresponds to the data shown in the upper part of FIG. Next, the position of the image pixel is adjusted so as to compensate for the deviation of the dot formation position according to the ejection characteristic data. For example, for black (K) ink having the ejection characteristic data shown in FIG. 12, the position of the image pixel is shifted to the right by one pixel as a whole as shown in the lower part of FIG. The print data may thus be generated in any order. It is sufficient that the number of left and right adjustment pixels in the print data is adjusted according to the ejection characteristic data.

In the print data, the number of adjustment pixels does not have to be set so that the absolute positions of dots are appropriate. It is the relative positional relationship between dots that affects the image quality. Therefore, the number of adjustment pixels may be set so that the formation position of another color matches the reference color. FIG. 14 is an explanatory diagram showing an example of an adjustment pixel distribution table set on the basis of black ink. This is a table set based on the ejection characteristic data shown in FIG. As shown in FIG.
Black (K) has a characteristic that dots are formed at positions shifted from the positions where they should be formed. FIG. 1 described earlier
In the adjustment pixel distribution table No. 3, the distribution of adjustment pixels is set so that black dots are formed at appropriate positions. On the other hand, the adjustment pixel distribution table in FIG. 14 sets adjustment pixels based on black dots. Therefore, the distribution of the adjustment pixels for black is always set to be equal in the left and right directions. In this example, two adjustment pixels are set on both the left and right sides.

On the other hand, for the other colors, adjustment pixels are allocated so that the relative positional relationship with black is appropriate.
According to the ejection characteristic data shown in FIG. 12, cyan (C) is 1 with respect to black (K) in the direction opposite to the carriage movement direction.
A dot is formed with a shift by a pixel. Therefore,
In order to compensate for such a shift, adjustment pixels are set with a distribution of three pixels on the left and one pixel on the right. Similarly, for magenta (M), adjustment pixels are set by distributing 0 pixels on the left side and 4 pixels on the right side. The yellow is formed at an appropriate timing according to the ejection characteristic data in FIG. 12, but when viewed on the basis of black, dots are relatively shifted by one pixel in the moving direction of the carriage. Will be. Accordingly, adjustment pixels are set for yellow (Y) with a distribution of one pixel on the left side and three pixels on the right side. The setting of the adjustment pixel can be set based on the predetermined color as described above.
In this case, since the adjustment pixels are always set at a constant distribution for black (K), there is an advantage that the processing is facilitated.

According to the printing apparatus described above, while using print data in which adjustment pixels are arranged at both ends of image pixels,
By changing the distribution of the adjustment pixels, it is possible to compensate for a shift in the dot formation position. Accordingly, dot displacement is suppressed, and high-quality printing without so-called color misregistration can be realized.

FIG. 15 is an explanatory diagram showing how the printing apparatus corrects the shift amount. The squares indicated by broken lines in the figure indicate pixels. ○ means a dot. The printer PRT realizes printing at a very high resolution, and forms dots that are sufficiently large with respect to the size of the pixel so that no gap occurs between adjacent dots.

FIG. 15A shows dots formed at appropriate positions. FIG. 15B shows a case where the dot formation position is shifted to the right in the drawing due to the ejection characteristics. The deviation of the dot formation position does not always occur in pixel units as shown in FIG. FIG. 15B shows a case where the shift amount of the formation position is less than one pixel. Even in such a case, the deviation amount is compensated for each pixel. In such a case, the distribution of the adjustment pixels is set so that a dot is formed on the left side by one pixel. FIG. 15C shows the state of the dots after the correction. Since the shift amount is less than one pixel, the shift remains in the dot formation position in FIG. However, FIG.
It can be seen that the displacement can be suppressed as compared with (b).

FIG. 15D shows an example in the case of having another ejection characteristic. Here, the case where the displacement of the formed dots is less than half a pixel is shown. In such a case,
If the shift amount is compensated in units of one pixel, the shift of the dot increases rather as shown in FIG. Therefore, in such a case, compensation for the deviation amount is not performed. Whether or not to perform compensation in accordance with the ejection characteristics as described above is controlled by the ejection characteristics data. When the deviation shown in FIG. 15B occurs, the value 1 is stored in the ejection characteristic data table (see FIG. 12).
Is stored, compensation for one pixel is performed, and FIG.
The printing is performed in the state shown in FIG. In the case where only a slight shift as shown in FIG. 15D occurs, if the value 0 is stored in the table of the ejection characteristic data (see FIG. 12), the shift is not compensated, and FIG. The printing in the state is realized. When a dot shift occurs in a width of one pixel or more, an appropriate value may be set in the ejection characteristic data according to the shift.

As described above, by distributing the adjustment pixels in accordance with the ejection characteristic data, the dot formation position can be finely adjusted in units of one pixel. In a printer PRT that realizes printing at a very high resolution, the width of one pixel is very short, so that the dot formation position in the main scanning direction can be sufficiently adjusted.

In the above-described method, the displacement of the dot formation position can be compensated by adjusting the positional relationship between the image pixel and the adjustment pixel. That is, a new hardware configuration is not required to compensate for such a deviation. Therefore, there is an advantage that the deviation can be compensated relatively easily and the image quality can be improved. Note that this method can be applied to both unidirectional printing and bidirectional printing, and in any case, the above-described effect is exhibited.

The above description has been made on the assumption that the displacement is compensated for the entire image data to be printed. On the other hand, the shift may be compensated only in an area where the shift of the dot greatly affects the image quality. For example, among various inks provided in the printer PRT,
For ink of a color with relatively low visibility such as yellow, compensation for misalignment may be omitted. It is generally known that in a region where dots are formed at an intermediate recording density, dot displacement has a large effect on image quality. In a low gradation area where the dot recording density is low or a high gradation area where the dot recording density is high, the shift of the formation position is hard to be recognized and the influence on the image quality is small. Therefore, the shift compensation may be performed only in the intermediate gradation where the shift of the dot formation position greatly affects the image quality, and the shift compensation may be omitted in other areas. As described above, if compensation for the shift is performed only in an area where the shift of the dot greatly affects the image quality, the processing load of the print data generation process can be reduced, and printing can be performed in a relatively short time. Becomes possible.

(3) Distribution of adjustment pixels for each nozzle: FIG.
FIG. 6 is a flowchart of a print data generation processing routine of another aspect. Here, only the differences from the flowchart of FIG. 7 are shown. As illustrated, the difference here is that the corresponding nozzle is determined prior to the adjustment pixel distribution setting process (step S40) (step S3).
5). In the above-described embodiment, the distribution of the adjustment pixels is uniformly set for each color, but here, the adjustment pixels are distributed for each nozzle. Therefore, prior to setting the distribution of the adjustment pixels, it is determined which nozzle will form the raster to be processed (step S35).

The determination of the corresponding nozzle will be described. FIG.
As shown in (1), the print head 28 of the printer PRT has a plurality of nozzles arranged at a constant nozzle pitch in the sub-scanning direction. The printer PRT prints an image by a so-called interlace method by performing sub-scanning at a predetermined feed amount. FIG. 17 is an explanatory diagram showing a state in which an image is printed by the interlace method.

The positions of the nozzles in each main scan are schematically shown on the left side of the figure. Each circled number indicates a nozzle. The dashed circles between the nozzles are for convenience indicating the nozzle pitch. Here, for the sake of illustration, a case where a head having four nozzles at a nozzle pitch of 3 dots is used is illustrated. When the head is sub-scanned by a feed amount equivalent to 4 dots, the head moves to the positions indicated by the first to fourth times in the drawing. The state of dots formed by performing main scanning at each position is shown on the right side in FIG. The numbers in the figure correspond to the nozzle numbers that form each dot. It should be noted that dots are not formed by the first nozzle in the first main scan, the second nozzle, and the first nozzle in the second main scan. Because you can't get it.

When the interlaced printing is performed as described above, the nozzle numbers that form each raster uniquely correspond to each other as shown in FIG. In step S35, nozzles forming each raster are determined based on the correspondence. As is well known, recording by the interlace method can be realized with various feed amounts according to the nozzle pitch and the number of nozzles. The nozzle number for forming each raster is uniquely determined according to each feed amount.

In this way, the nozzles forming each raster are determined (step S35), and adjustment pixel distribution setting is performed for each nozzle (step S40). The concept of setting the distribution of the adjustment pixels is the same as that described above. In all aspects of the description,
The difference is that the ejection characteristic data is provided for each nozzle, whereas the ejection characteristic data is provided for each ink.

According to the method described above, it is possible to compensate for the deviation of the formation position in consideration of the ink ejection characteristics of each nozzle. Therefore, dot displacement can be suppressed,
Higher quality printing can be realized. Note that this method can be applied to both unidirectional printing and bidirectional printing, and in any case, the above-described effect is exhibited.

In this embodiment, it is not always necessary to individually provide ejection characteristic data for all nozzles.
For example, the ejection characteristics data may be provided for each nozzle row shown in FIG.

(4) First Embodiment: (4-1) Generation of Print Data: The hardware configuration of the printing apparatus according to the embodiment is as described above (see FIGS. 1 to 4).
In this embodiment, dot displacement is corrected in bidirectional printing, that is, a printing method in which printing is performed in both directions of the carriage.

FIG. 18 is a flowchart of a print data generation processing routine in the embodiment. This process is a process executed by the CPU of the computer PC. When this processing is started, the input unit 100 and the color correction processing unit 101
The halftone processing unit 102 (see FIG. 2) performs input of image data, color correction processing, and halftone processing, respectively (steps S10, S20, and S30). These processes are the same as the processes in FIG.

Next, the print data generation unit 103 performs a process for determining the corresponding nozzle and the forming direction (step S3).
5). As described in the previous embodiment (see FIG. 17), if the feed amount by the interlace method is set, the corresponding nozzle is uniquely set. In step S35, the corresponding nozzle is determined by the same method as in the above embodiment. In this embodiment, printing is performed in both directions of the carriage reciprocation. FIG.
When the printing is performed with the feed amount shown in (1), the odd-numbered main scanning is performed while moving the carriage, and the even-numbered main scanning is performed while moving the carriage backward. Therefore, FIG.
As is clear from the above, if the interlace feed amount is set, not only the nozzles forming each raster are set, but also the raster formed during the forward movement or the raster formed during the backward movement is uniquely set Is done. Step S of this embodiment
At 35, the corresponding nozzle and the forming direction are determined in accordance with such a correspondence relationship.

Next, the print data generation unit 103 determines whether the raster to be processed is a raster formed at the time of forward movement (step S42). If the raster is formed during the forward movement, the adjustment pixel number setting unit 108 sets the adjustment pixels based on the adjustment pixel distribution table set for the forward movement (step S44). When the raster is formed at the time of the backward movement, the adjustment pixels are set based on the adjustment pixel distribution table set for the backward movement (step S).
46). As described above, in this embodiment, the adjustment pixel distribution table is properly used according to the moving direction of the carriage when forming each raster.

The reason why such separate use is necessary will be described. FIG. 19 is an explanatory diagram showing the relationship between the moving direction of the carriage and the shift amount of the dot formation position. FIG.
(A) shows a state in which a dot is formed while the carriage moves to the right (forward movement). For example, 3 in the figure
When the ink is ejected at the timing of forming a dot on the fourth pixel, it is assumed that the fourth pixel actually has a discharge characteristic of forming a dot on the fourth pixel. FIG. 19B shows a state in which the carriage forms dots while moving (returning) to the left. When printing is performed while the print head having the ejection characteristics shown in FIG.
If ink is ejected at the timing when dots should be formed on the second pixel, a dot is formed on the second pixel. The displacement of the dots formed in this way reverses the direction between the forward movement and the backward movement.

FIG. 20 is an explanatory diagram showing the relationship between the moving direction of the carriage and the compensation of the deviation amount. 20 shows a state corresponding to the ejection characteristics shown in FIG. As shown in FIG. 19A, at the time of forward movement, one point is located on the left side of the position where it should be formed.
Dots are formed at positions shifted by pixels. To compensate for such a shift, print data is generated by shifting the image pixels by one pixel to the right during forward movement. In other words, the adjustment pixels are allocated to three pixels on the left side and one pixel on the right side. As shown in FIG. 19B, at the time of the backward movement, a dot is formed at a position shifted by one pixel to the right from the position where it should be formed. In order to compensate for such a shift, print data is generated by shifting the image pixel by one pixel to the left at the time of the backward movement. In other words, one adjustment pixel is allocated to the left side and three adjustment pixels are allocated to the right side. As described above, since the direction in which the dots are shifted differs depending on the moving direction of the carriage, the distribution of the adjustment pixels for compensating the shift is also different.

In this embodiment, in consideration of such a difference, the distribution of adjustment pixels is set according to the moving direction of the carriage when forming a raster (step S4 in FIG. 18).
4, S46). The setting of such distribution is realized by providing two types of adjustment pixel distribution tables, one for forward movement and the other for backward movement. If the displacement of the dot formation position is caused only by the difference in the ink ejection characteristics, as shown in FIG.
The distribution of the adjustment pixels is reversed left and right between the forward movement and the backward movement. Explaining with reference to the example of FIG.
The adjustment pixels set by the distribution of one pixel on the right and one pixel on the right are set by the distribution of one pixel on the left and three pixels on the right during the backward movement. Therefore, the processing in steps S44 and S46 is 1
The correspondence between the type of adjustment pixel distribution table and the distribution to the left and right may be reversed according to the moving direction of the carriage to set the adjustment pixels.

When the adjustment pixel number setting unit 108 sets the distribution of the adjustment pixels in consideration of the moving direction of the carriage, the print data generation unit 103 performs rasterization and output of the print data (steps S50 and S60). The contents of these processes are the same as those shown in FIG. Also,
The above processing is repeated until the processing is completed for all rasters (step S70). Hereinafter, the configuration of the print data of this embodiment will be described.

FIG. 21 is an explanatory diagram showing the contents of print data in this embodiment. At the head of the print data, overall print information is provided, in which information such as the nozzle pitch of the head, the resolution of the image, and the amount of buffer that needs to be secured on the printer PRT side is stored. After the entire header, raster data and sub-scan feed data for each pass (one of the forward and backward movements of the main scanning) are arranged.

A header section is provided at the head of each raster data. The header section stores a reciprocating flag indicating whether the raster data is used in the forward scan or in the backward scan. The printer PRT forms dots in the forward or backward movement of the main scan based on the reciprocating data. After the header portion, raster data for each ink, which is dot formation information for each ink, is arranged in the order of black, cyan, magenta, and yellow. Then, as shown in the middle and lower parts of FIG. 21, each header part is provided at the head of each ink-specific raster data. The header portion of the raster data for each ink stores a color code indicating the color of the ink and adjustment number data (adjustment pixel arrangement data) indicating the number of adjustment pixels arranged in the ink. After the header,
Pixel value data for each nozzle is provided. The pixel value data includes image pixel data and adjustment pixel data (see FIGS. 11 and 20) corresponding to each nozzle. This image pixel data is data representing a dot formation state in image pixels constituting an image to be printed. The adjustment pixel data is data indicating the presence of an adjustment pixel that does not form a dot and is used for adjusting the position of an image pixel in the main scanning direction. The adjustment pixel data has the same format as the image pixel data and is arranged on at least one of both ends of the image pixel data. As shown in FIG. 11, the image pixel data and the adjustment pixel data for each nozzle are corrected to shift the pixels. In other words, the number of arranged adjustment pixels is set so as to reduce the deviation of the dot formation position in the main scanning direction between the forward movement and the backward movement. However, the distribution of adjustment pixels is common to nozzles that eject ink of the same color.

In this specification, the term “raster data” in a narrow sense means the entire dot formation information relating to the nozzles of all the inks in each pass (FIG. 2).
In a broad sense, it may mean raster data by ink, which is dot formation information for one pass of one type of ink, or dot formation information for one pass of one nozzle.

According to the configuration described above, when bidirectional printing is performed, printing can be performed while compensating for dot deviation, and image quality can be improved. Bidirectional printing has the advantage of high printing speed and tends to be used frequently. On the other hand, in bidirectional printing, the dot formation position is liable to be affected by backlash or the like of the main scanning mechanism, and is likely to shift in the main scanning direction. According to the printing apparatus of the above embodiment, such deviation can be easily compensated, so that the image quality in bidirectional printing can be greatly improved, and high-speed and high-quality printing can be realized.

In this embodiment, an example has been described in which the deviation is compensated for each ink. On the other hand, the deviation may be compensated for each nozzle row or for each nozzle. Each color of ink may be ejected from a plurality of nozzle rows as shown in FIG. Therefore, in such a case, if the deviation is compensated for each nozzle row, the dot formation position deviation can be compensated more finely. If the deviation is compensated for each nozzle, the dot formation position deviation can be compensated more finely according to the characteristics of the nozzle.

(4-2) Execution of printing and alteration of print data: In this embodiment, if printing is temporarily interrupted for some reason, print data originally intended to be used for resuming printing in main scanning. Is used in the forward printing, and when the print data to be used in the forward movement is to be used in the backward movement, the print data is modified in the printing apparatus and printing is executed.

The case where the direction of the pass performed by the printer PRT and the direction indicated by the reciprocating flag of the raster data to be used are reversed will be described. Normally, print data is provided such that the direction of the reciprocating flag of the first raster data in the print data matches the direction of the first pass of the printer PRT. For this reason, the direction of the reciprocating flag of the subsequent raster data and the direction of the next pass that the printer PRT is going to perform usually coincide. However, when the following situation occurs, the directions of the two are reversed. For example, when a predetermined event to interrupt printing occurs, such as when the cartridge runs out of ink or the time when periodic flushing should be performed, the control circuit 40 of the printer PRT stops printing at the time when the current pass is completed. . Then, the head is moved to the standby position. The head standby position is provided at one end of the moving range of the carriage 31. Therefore,
When the printing is stopped, if the head is on the side other than the side where the standby position is provided, the head runs idle toward the side where the standby position is located. The scan in which the head moves upward from the standby position to the printing paper is the forward movement (odd pass), and the scan in which the head moves from the print paper toward the standby position is the backward movement (even pass).

While the printing is stopped, the printing device PR
T automatically performs periodic flushing, or the user replaces the ink cartridge, so that predetermined treatment is performed. Thereafter, when printing is resumed, the printer PR
The head T restarts scanning during printing from main scanning (forward movement) in a direction in which the head moves upward from the standby position. Therefore, if the main scan scheduled to be performed next is the forward movement immediately before the stop of printing, after the printing is resumed, the direction of the path scheduled to be performed next by the printer PRT and the raster data of the raster data to be used next are determined. The direction indicated by the round trip flag matches. However, if the main scan scheduled to be performed next is a return movement immediately before printing is stopped, the direction of the pass performed by the printer PRT and the direction of the reciprocation flag of the raster data are reversed after printing is resumed.

FIG. 22 is an explanatory diagram showing a printing result when the corrected pixel value data is used in a predetermined direction. For a certain nozzle, if the ink droplet ejection speed is slightly earlier than the assumed timing, or if the ink droplet ejection speed is slightly faster than the assumed timing, the ink The landing position of the droplet is shifted in the direction opposite to the main scanning direction. In FIG.
This shows a case where the dot formation position shift is substantially one pixel. In such a case, the number of adjustment pixels arranged in front of the scanning direction with respect to the image pixels is reduced by one, the number of pixels arranged behind is increased by one, and the image pixels are moved forward by one pixel in the main scanning direction. By shifting the position, the ink droplet can be landed near the expected position. That is, as shown in the upper part of FIG. 22, for the raster data used in the forward movement, the pixel value data is corrected by reducing one adjustment pixel on the right side and increasing one adjustment pixel on the left side in FIG. In the forward movement, the raster data is used in order from the left, and thus such correction causes the ejection timing of the ink droplet to be delayed by one pixel. Therefore, the printing result at the time of the forward movement is close to the “desired printing result” shown in the middle part of FIG. On the other hand, as for the raster data used in the backward movement, as shown in the lower part of FIG. 22, the pixel value data is corrected by decreasing one adjustment pixel on the left side of FIG. 22 and increasing one adjustment pixel on the right side. In the backward movement, since the raster data is used in order from the right, such correction also causes the ejection timing of the ink droplet to be delayed by one pixel, and the print result is close to the “desired print result”. As described above, by correcting the pixel value data in accordance with the forward movement and the backward movement, it is possible to reduce the deviation between the dot formed in the forward movement and the dot formed in the backward movement.

FIG. 23 is an explanatory diagram showing a print result when the corrected pixel value data is used in the direction opposite to the expected direction. As shown in the upper part of FIG. 23, when the pixel value data originally corrected for the backward movement (in the direction opposite to the forward movement) is used in the forward movement, the dot formation position shift is reduced from one pixel to two pixels. It will increase. Also, when the pixel value data originally corrected for the forward movement (in the direction opposite to the backward movement) is used in the backward movement, the dot formation position deviation is increased as shown in the lower part of FIG. I will. As a result, a total of 4
Pixels are also shifted in dot formation position. This is because the directions of correction are reversed between the forward movement and the backward movement, and the distribution numbers of the left and right adjustment pixels are reversed. Therefore, when raster data corrected for the backward movement is used for printing in the forward movement,
When the raster data corrected for the forward movement is used at the time of the backward printing, it is necessary to reverse the numbers of the right and left adjustment pixels sandwiching the image pixels. Here, the case where the dot formation position is shifted by one pixel in the direction opposite to the scanning direction has been described as an example. I can say.

FIG. 24 shows the expansion buffer 44 (see FIG. 2).
9 is a flowchart showing a print execution routine when printing is performed using raster data for one pass sent to the printer. When one pass of raster data (see the middle part of FIG. 21 and FIG. 2) is sent from the reception buffer 115 into the expansion buffer 44, the control circuit 40 of the printer PRT determines the direction of the pass to be performed next and the raster data. The direction indicated by the reciprocation flag is compared (step S210). If the direction of the path of the printer PRT matches the direction of the round trip flag,
The control circuit 40 performs main scanning according to the raster data,
A dot is formed (Step S230). On the other hand, if the direction of the path of the printer PRT does not match the direction of the reciprocating flag for some reason, the pixel value data modifying unit 120 of the CPU 41 included in the control circuit 40 (FIG.
3) alters the distribution of the adjustment pixels in the print data (step S220). This pixel value data modification unit 12
0 corresponds to the path reversal detecting unit and the raster data reconstructing unit of the claimed invention. This pixel value data modification unit 12
0, specifically, the CP in the control circuit 40
U41 is realized using the expansion buffer 44.

FIG. 25 is an explanatory diagram showing the details of the modification of the pixel value data for using the pixel value data corrected for the backward movement in the forward movement. The pixel value data modification unit 120 (see FIG. 2) modifies the distribution of the adjustment pixels in the print data in step S240 to an arrangement in which image pixels are interposed. In FIG. 25, squares with oblique lines are image pixels, and white squares are adjustment pixels.
The control unit 40 handles the image pixels and the adjustment pixels collectively as pixels without discrimination. However, based on the adjustment number data stored in the header part of the raster data for each ink, it is specified which of the pixels is the adjustment pixel,
The following processing can be performed.

In FIG. 25, in the corrected pixel value data for the backward movement before modification, three adjustment pixels are arranged on the right side of the image pixel and one adjustment pixel on the left side. However, in order to use the pixel value data in the forward movement, the pixel value data modification unit 120 modifies the arrangement of the adjustment pixels so that the number of the adjustment pixels is one on the right side of the image pixel and three on the left side of the image pixel. As a result, the modified raster data is corrected pixel value data for forward movement (FIG. 22).
(See upper section). After modifying the distribution of the adjustment pixels of the pixel value data in this way (step S220), the control circuit 40 forms dots according to the pixel value data (step S230).

As described above, in this embodiment, when the combination of the raster data and the scanning direction when executing the raster data is reversed due to the interruption of the printing, the pixel value data is modified. Therefore, it is possible to appropriately compensate for a dot formation position shift in which the shift direction is reversed between the forward movement and the backward movement. Such a dot formation position deviation also occurs due to a deviation of the ejection timing or the ejection speed of the ink droplet from each nozzle from an assumed value. In addition, differences in characteristics such as viscosity between ink colors also cause differences such as a difference in the ejection speed of ink droplets, which may cause a dot misalignment.

Further, round-trip data is provided corresponding to each raster data. Therefore, based on the reciprocating data, it is possible to check whether the “pass scheduled to be performed next before printing is stopped” is a forward movement or a backward movement. And 1
Even if the printing is interrupted several times during the printing of a sheet of paper and the relationship between the raster data and the scanning direction is switched several times, the scanning direction that is actually scheduled to be performed each time, By comparing the round trip data, the raster data can be appropriately modified as needed.

(4-3) Modifications of First Embodiment: The present invention is not limited to the above-described embodiments and embodiments, and may be carried out in various modes without departing from the scope of the invention. It is possible, for example, the following modifications are also possible.

For example, in the above-described embodiment, each time printing is performed, the direction of the next pass to be performed is compared with the direction indicated by the reciprocation flag of the raster data. However, the present invention is not limited to such an embodiment. That is, until printing is interrupted by a predetermined event, a dot is formed without comparing the direction of the next pass to be performed with the direction indicated by the reciprocation flag of the raster data, and the printing of the printing by the predetermined event is performed. The comparison may be performed every time after the interruption occurs. With such an embodiment, the processing in the case where the printing is not interrupted can be simplified.

In the above embodiment, the standby position is provided at one end of the moving range of the carriage 31, and the scanning in which the head moves upward from the standby position to the printing paper is fixed to the forward movement. Therefore, the print data is modified when the “pass scheduled to be performed next before the stop of printing” is a return. On the other hand, when printing is interrupted, the carriage 31
If the head can be stopped at both ends of the movement range, the path after printing is resumed may be forward movement or backward movement. Therefore, in such a case, the "pass that was scheduled to be performed next before printing was stopped"
Compare with "Pass to be performed after resuming printing"
If the scanning directions (forward and backward) of the path do not match, it is necessary to modify the data (see FIG. 24).

FIG. 26 is an explanatory diagram showing a printer according to a modification of the first embodiment. In the above-described embodiment, the print data generation unit 103 of the printer driver 96 generates the adjustment pixel data representing the adjustment pixel and sends it to the printer PRT together with the image pixel data. However, the printer driver 96 generates only the adjustment number data without generating the adjustment pixel data, and the printer PRT generates the adjustment pixel data (see FIGS. 6 and 20) in accordance with the distribution of the adjustment pixels indicated by the adjustment number data. It may be that. In such an embodiment, the CPU 41 functions as the adjustment pixel data generation unit 121 (see FIG. 26), and adds the adjustment pixel data to the dot formation information for one pass in the development buffer 44.

In the above-described embodiment, the adjustment number data is provided for each ink-specific raster data (FIG. 2).
1), and the adjustment number data may be collectively stored in the overall print information (see FIG. 21). For example,
When the arrangement of the adjustment pixels is different for each ink color, the adjustment number data for each ink color can be stored in the overall printing information.

(5) Second Embodiment FIG. 27 is an explanatory diagram showing the configuration of the functional blocks of the second embodiment. In the second embodiment, as a functional block of the printer driver 96, in addition to the input unit 100 and the output unit 104, a normal print module 105, a test pattern print module 106, and a test pattern data storage unit 107 are provided. Printer PRT
The configuration on the side is the same as the embodiment shown in FIG.

The normal printing module 105 comprehensively shows the color correction processing unit 101 and the color correction table LUT, the halftone processing unit 102, the print data generation unit 103, and the adjustment data distribution table AT in FIG. 2 as one functional block. It is something. The test pattern printing module 106 has the test pattern data storage 10
The test pattern is printed according to the test pattern stored in 7. Therefore, the second embodiment corresponds to a device having a new function of printing a test pattern, in addition to the function of the mode described in the principle above.

The printer driver 96 inputs a command from the keyboard 14 and a print command from the application 95 via the input unit 100. In response to a print command from the application program 95, image data is received from the application program 95,
The signal is converted into a signal that can be processed by the printer PRT by the normal print module 105. The contents of this processing are the same as those in the mode described above.

One of the processes executed by the printer driver 96 in response to an instruction from the keyboard 14 is a process of adjusting the dot formation timing of the printer PRT. When the formation timing adjustment process is instructed,
The printer driver 96 uses the test pattern printing module 106 to execute the test pattern data storage unit 10 in advance.
The test pattern is printed in accordance with the test pattern data stored in. Data for printing the test pattern is output from the output unit 104 to the printer PRT. The printer PRT receives this data and prints a predetermined test pattern.

When adjusting the dot formation timing, the user designates the optimum printing timing from the keyboard 14 based on the printing result of the test pattern. The printer driver 96 inputs designation of print timing via the input unit 100. Further, adjustment distribution data (see FIG. 2) is set according to the input timing. In addition, the input timing is transferred to the printer PRT,
The ejection characteristic data stored in the printer PRT may be rewritten. With these functional blocks, the printing apparatus according to the second embodiment prints an image while compensating for the shift amount, sets the compensation amount for the shift amount according to the test pattern, and adjusts the dot formation timing. it can. Hereinafter, a process for adjusting the dot formation timing will be described by taking as an example a case where the timing is adjusted for each color in a printing apparatus that performs bidirectional printing. FIG. 28 is a flowchart of the dot formation timing adjustment processing. This processing is performed by the CP on the computer PC side.
This is the process performed by U. That is, the computer PC
The CPU on the side corresponds to a deviation amount setting unit in the claimed invention.

When this process is started, the CPU first adjusts the dot formation timing for black (K). As a process for this, first, a test pattern for K is printed (step S100). The test pattern data is stored in the test pattern data storage unit 107 in advance as test pattern data. The data for printing the test pattern is stored in the printer PRT.
, A predetermined test pattern is printed.

FIG. 29 is an explanatory diagram showing an example of a test pattern. In the drawing, white circles indicate dots formed during the forward movement, and solid circles indicate dots formed during the backward movement. The test pattern is recorded by changing the dot formation timing at the time of the backward movement into five stages indicated by numbers 1 to 5. The change in the formation timing is realized by shifting the image data of the test pattern in the main scanning direction in pixel units. The pattern shown in FIG. 29 is formed such that the dot recording position at the time of backward movement is relatively shifted left and right with respect to the recording position of the dot at the time of forward movement.

The user of the printer PRT compares the printed test patterns and selects the one on which the best image is recorded. The CPU inputs the designated value of the selected formation timing (step S105).
In the example shown in FIG. 29, at the timing of number 4,
Since the recording positions of the dots at the time of the forward movement and the time of the backward movement match, "4" is input as the formation timing. The input data is temporarily stored as a timing table.

Next, the CPU determines whether or not the setting of all the formation timings has been completed (step S110). In this embodiment, not only black but also cyan, magenta,
The formation timing is adjusted for all the yellow colors. At this point, since the adjustment of the formation timing has only been completed for black, the CPU determines that the setting of the formation timing has not been completed, and shifts to the adjustment of the formation timing for cyan.

The adjustment of the formation timing of cyan is performed by the same method as that for black. First, the CPU prints a predetermined test pattern (step S100). Here, the formation timing of cyan is adjusted based on black. FIG. 30 is an explanatory diagram showing a test pattern for adjusting the relative positional relationship between black and cyan. The dots indicated by circles in the figure indicate the dots formed during the forward movement of black. The dots indicated by squares indicate dots formed during the forward movement of cyan. FIG.
Similarly to the above test pattern, the cyan dot is formed by shifting the image data of the test pattern step by step in the main scanning direction in pixel units.

By specifying the most appropriate formation timing based on the test pattern, the formation timing at the time of the forward movement of cyan can be matched with the timing at the time of the forward movement of black. The user of the printer PRT
As in the case of black, an appropriate formation timing is specified. The CPU inputs this designation (step S10).
5), and temporarily store it as a timing table. FIG.
In the example shown in FIG. 7, since the recording positions of the black and cyan dots match at the timing of number 2, "2" is input as the formation timing.

Subsequently, the CPU adjusts the timing of forming cyan at the time of the backward movement. As a test pattern, FIG.
A square dot of 0 is formed at the time of cyan return. Further, for magenta and yellow, adjustment of the formation timing at the time of forward movement and adjustment of the formation timing at the time of backward movement are individually performed. When the adjustment of the forming timing in each direction is completed for each color (step S11)
0), the adjustment pixel distribution table is set based on the stored formation timings (step S11).
5). The formation timing for each color and direction corresponds to a shift in dot formation position expressed in pixel units. That is, it corresponds to the ejection characteristic data in the mode when the principle has been described above. The method of setting the adjustment pixel distribution table based on such data is as already described in the mode when the principle was described earlier (see FIG. 11).

According to the printing apparatus of the second embodiment described above, even if the dot formation position shifts after shipping, the user can set the stored shift amount relatively easily. it can. As a result, high-quality printing can be relatively easily maintained, and the convenience of the printing apparatus can be improved.

The above-described method of adjusting the formation timing is merely an example, and the adjustment of the formation timing may be successively performed by repeatedly performing the input of the formation timing and the printing of the test pattern based on the formation timing. . Further, functions corresponding to the computer PC, the printer driver 96 and the input unit 100 are provided by the printer P.
The printer PRT alone may be provided in the RT main body to adjust the dot formation timing.

FIG. 31 shows a method of adjusting the formation timing as a modification of the second embodiment. FIG. 31 is an explanatory diagram showing the relationship between a reference color for adjusting the formation timing and a color whose timing is to be adjusted. In the second embodiment, as shown in the figure, based on the dot at the time of forward movement of K, the time of backward movement of K, the time of forward movement and backward movement of cyan, the time of forward movement and backward movement of magenta, and the forward movement of yellow. The forming timing at the time of moving and returning is adjusted. In this case, a total of seven types of test patterns are printed.

On the other hand, as a first modification, the formation timing of each color other than yellow and each direction may be adjusted based on the forward movement of K. In this case, the yellow formation timing may be set to be the same as the K timing, or may be fixed to a predetermined reference timing. By doing so, the types of test patterns to be printed can be reduced, and the time required for adjusting the formation timing can be reduced. In yellow, the shift of the dot formation position is hard to be visually recognized, and thus the influence of the formation position on the image quality is small. Therefore, even if the adjustment of the formation timing for the yellow is omitted, the image quality is not significantly impaired.

Of course, as long as the color has little effect on the image quality, the adjustment of the formation timing for the color other than yellow can be omitted. In this embodiment, the printer PR
T has four color inks. On the other hand, in a printer including six colors of ink in which cyan of low density and magenta of low density are added, adjustment of the formation timing of these inks of low density may be omitted.

As shown in Modification 2 in FIG. 31, the formation timing may be individually adjusted for each color. That is, in the same manner as adjusting the backward movement of K based on the forward movement of K, the formation timing of each of the backward movements of C, M, and Y based on the forward movement of C, M, and Y To adjust. In a printer in which the formation timing between colors is unlikely to shift, if the formation timing is adjusted by such a method, the dot formation timing can be easily adjusted, and the image quality can be improved.

As shown in Modification 3 in FIG. 31, the dot formation timing at the time of forward movement and the backward movement may be adjusted by K, and the formation timing between colors may be adjusted only at the time of forward movement.
At this time, the formation timings at the time of forward movement and at the time of backward movement are collectively adjusted for all colors based on the K adjustment result. If the difference between the dot formation timings at the time of forward movement and at the time of backward movement is caused by a factor that is considered to have a small difference between colors, such as backlash or paper heat, adjusting the formation timing by such an adjustment method, The formation timing of each color can be easily adjusted, and the image quality can be improved.

Of course, the method of adjusting the formation timing is as follows.
Various other combinations are also conceivable. For example, in the second modification and the third modification, the yellow adjustment may be omitted. Further, both Modification 2 and Modification 3 may be performed. Further, the user may be allowed to select a method of adjusting the formation timing from these adjustment methods. Also, various patterns can be applied to the test pattern.

(6) Third Embodiment FIG. 32 is an explanatory diagram showing functional blocks of a printing apparatus. In the third embodiment, the head drive unit 113a of the printer PRT and the computer PC
Is different from that of the first embodiment. Other points are the same as in the first embodiment. The head drive unit 113a of the printer PRT includes a drive signal generation unit 11
6 is provided. Although the description is omitted in the first embodiment, the drive signal generation unit also includes the head drive unit 113 of the first embodiment. However, the drive signal generation unit 116 of the third embodiment
Has a feature that a drive signal for driving each nozzle is generated based on four original drive signals as described later. Further, the print data generation unit 103a includes a path decomposition unit 109 that determines which of the four image pixels in the raster is to be recorded based on the original drive signal.

Although the description is omitted in the first embodiment, the head driving unit 113 of the printer PRT generates an original driving signal that repeats the same waveform, and the piezo element provided for each nozzle according to the original driving signal. , A drive signal for selectively driving is generated to eject ink droplets.
Therefore, when the speed of the main scanning of the print head 28 is constant, how dense the pixels can be recorded by the printer PRT depends on how high the original drive signal can be. . However, due to various factors such as the mechanical characteristics of the piezo element, the frequency of the original drive signal may not be able to be increased to a certain degree or more. In the third embodiment, by generating a plurality of original drive signals having phases shifted from each other, it is possible to generate dots at a high density equivalent to that when the original drive frequency is generated at a frequency several times higher than the actual original drive frequency. Enable recording.

FIG. 33 is a block diagram showing the structure of the drive signal generator 116 provided in the head driver 113 (see FIG. 2). Actually, a head has a large number of nozzles, and can perform both unidirectional printing and bidirectional printing. Here, however, the driving signal is described using the simplest example of unidirectional printing with four nozzles. The configuration of the generation unit 116 will be described. The drive signal generator 116 includes a plurality of mask circuits 2
04 and an original drive signal generator 206. The mask circuit 204 includes a nozzle n1 of the ink discharge head 61a.
To n4 are respectively provided corresponding to a plurality of piezo elements for driving. In FIG. 33, the number in parentheses added to the end of each signal name indicates the number of the nozzle to which the signal is supplied. Original drive signal generator 206
Are the original drive signals O supplied to the nozzles n1 to n4, respectively.
DRV1 to ODRV4 are generated. These original drive signals are ODRV1, ODRV2, ODRV3, ODRV4
In the order of 1/4 period. Below,
ODRV1, ODRV2, O
If there is no need to distinguish between DRV3 and ODRV4,
It is described as “ODRV”. In the drawing, the waveform of one cycle of the original drive signal is represented by one rectangular wave for simplicity, but in actuality, as shown in the lower right of FIG. 33, the characteristics of the piezo element are considered. It is a complicated waveform determined as follows. One cycle of the waveform including the pulses W1 and W2 is a one-cycle waveform for recording one pixel.

As shown in FIG. 33, the serial print signal P
RT (i) is input to the mask circuit 204 together with the original drive signal ODRV output from the original drive signal generator 206. The mask circuit 204 receives the serial print signal PRT.
A gate for partially or entirely masking the original drive signal ODRV according to (i). That is, when a certain section of the serial print signal PRT (i) is at the 1 level, the mask circuit 204 passes the corresponding portion (pulse W1 or W2) of the original drive signal ODRV as it is and drives the drive signal DRT.
RV is supplied to the piezo element. On the other hand, when a certain section of the serial print signal PRT (i) is at the 0 level, a corresponding portion (pulses W1 and W2) of the original drive signal ODRV is cut off.

The original drive signals ODRV1 to ODRV4 are 1
The waveform for the cycle is a waveform for recording one pixel. However, since these are generated by shifting the phase every quarter cycle, if dots are continuously formed using the original drive signals ODRV1 to ODRV4, four dots are formed during one cycle of the original drive signal. Pixels can be recorded. Therefore, adjacent pixels in one raster are respectively referred to as original drive signals ODRV1 to ODRV1.
If dots are formed by allocating to four, dots can be recorded at four times higher density than when only one original drive signal ODRV is used. Here, in order to simplify the explanation, the number of nozzles is set to four, and each original drive waveform is supplied to only one nozzle. However, actually, the head is provided with a number of nozzles, and the original drive waveforms ODRV1 to ODRV4 are supplied to the piezo elements of the plurality of nozzles.

FIG. 34 is an explanatory diagram showing how the pass decomposition section 109 (see FIG. 32) divides pixels in one raster into pixel groups. The path decomposition unit 109
The pixels in the raster are divided into a first pixel group to a fourth pixel group depending on which original drive signal is to be recorded. Here, since each original drive signal is supplied to only one nozzle, the pixels in the raster are divided into a first pixel group to a fourth pixel group depending on which nozzle is used to print each pixel. FIG. 34 shows a case where there are four adjustment pixels prior to the image pixels x1, x2, and the like. These adjustment pixels ax1
To ax4 and the image pixels x1 and x2 are not distinguished from each other depending on whether they are image pixels or adjustment pixels, and the first pixel group, the second pixel group,
Sorting is performed repeatedly in the order of the third pixel group and the fourth pixel group. That is, the j-th pixel (j is a natural number) from the top in the raster is assigned to the first pixel group if the remainder obtained by dividing j by 4 is 1, and if the remainder is 2, the second pixel is assigned to the second pixel group. Pixel groups. If the remainder is 3, it is assigned to the third pixel group, and if j is divisible by 4, it is assigned to the fourth pixel group. This sorting method is the same regardless of whether the target pixel is an image pixel or an adjustment pixel. As shown in FIG. 34, as a result of the sorting, the pixels ax1, x1,
x5, x9,... belong to the second pixel group, and pixels ax2, x2, x6, x10,. The third and fourth pixel groups are also as illustrated.

In the sub-scan feed in this example, each nozzle
Nozzles n1, n2, n3, and n4 arrive at a specific raster in this order (see FIG. 33). Therefore, the first main scan for printing a specific raster is performed by the nozzle n1, and the second main scan is performed by the nozzle n2. The third main scan is performed by the nozzle n3,
The second main scan is performed by the nozzle n4. Since the specific original drive signals ODRV1 to ODRV4 are supplied to the respective nozzles, the first pixel group includes the original drive signals ODRV
V1 is recorded, and the second pixel group is recorded by the original drive signal ODRV2. And
The third pixel group is recorded with the original drive signal ODRV3, and the fourth pixel group is recorded with the original drive signal ODRV4.

FIG. 35 is a diagram showing which cycle of each original drive waveform each pixel corresponds to. In the first pixel group, pixels ax1, x1, x5, x9,... Correspond to each cycle in order from the top of the original drive waveform ODRV1. Similarly, the second pixel group includes the original driving waveform OD
Pixels ax2, x2,
x6, x10,... correspond. The third pixel group,
The same applies to the fourth pixel group.

FIG. 36 is an explanatory diagram showing how each pixel in one raster is recorded. In the figure, each square indicates a pixel, and a circle in the pixel indicates a dot to be formed. However, circles with broken lines indicate dots that are not formed. Further, 1P in the circle indicates that the dot is a dot recorded in the first main scan. Similarly, 2P indicates that the dot is a dot recorded in the first main scan. The same applies to 3P and 4P. When the nozzle n1 reaches the target raster and main scanning is performed, pixels x1, x5, x9,... Are recorded by the nozzle n1 as shown in FIG. Here, since the pixel ax1 is an adjustment pixel, no dot is formed. Next, when sub-scanning is performed and the nozzle n2 reaches the target raster, pixels x2, x6, x10,... Are recorded, as shown in FIG. Similarly, no dot is formed on the adjustment pixel ax2.
Since one nozzle forms dots by one original drive signal, dots can only be formed at a density of one pixel out of four pixels in one main scan. However, since the original drive waveforms ODRV1 and ODRV2 are shifted in phase by 1/4 cycle, a dot can be formed adjacent to a pixel shifted by 1 pixel corresponding to 1/4 cycle. Similarly, when the nozzle n3 reaches the target raster by sub-scanning, pixels x3, x7, x11,... Are recorded as shown in FIG. Then, when the nozzle n4 reaches the target raster and the pixels x4, x8, x12,... Are printed as shown in FIG. 36 (d), the printing of all the image pixels of the target raster is completed. .

Here, one raster is recorded by four nozzles arranged side by side in the sub-scanning direction. Therefore, in order to complete the recording of all pixels of one raster, four raster scans are performed. During that time, three sub-scans were required. However, the pixels in each pixel group may be recorded based on different original drive signals. Therefore, if the nozzles that form dots with different original drive signals are arranged side by side in the main scanning direction, if the pixels of each pixel group are to be recorded by those nozzles, one raster scan is performed in one main scan. Can be completed. That is, in the third embodiment, the pixels in each pixel group may be recorded based on different original drive signals, and what kind of main scanning and sub-scanning are performed during the recording is not limited. Absent. Also, as long as the pixels of each pixel group are recorded based on different original drive signals, it does not matter which dot each pixel is recorded by.

FIG. 37 is an explanatory diagram showing how the pass decomposition unit 109 generates a pixel group when there are three adjustment pixels. In the above description, the case where the number of the adjustment pixels arranged before the image pixel is four has been described. Here, the case where the number of the adjustment pixels is three will be described. The adjustment pixels ax1 to ax3 and the image pixels x1, x2,... In the raster are repeatedly allocated to the first to fourth pixel groups in order from the head pixel, as in the above-described case. As a result of the sorting, pixels ax1, x2, x6, x10,... Belong to the first pixel group, and pixels ax2, x3, x7, x1 belong to the second pixel group.
1, 1 and 2 belong. The third and fourth pixel groups are also as illustrated. As can be seen from FIGS. 34 and 37, when the number of the adjustment pixels is four, the first image pixel x1 is located at the second position of the first pixel group. Is at the beginning. Similarly, for other image pixels after x2,
The pixel group to which the adjustment pixel ax4 belongs is shifted and shifted by an amount corresponding to the absence of the adjustment pixel ax4.

FIG. 38 is a diagram showing, in a case where there are three adjustment pixels, the number of cycles of each original drive waveform corresponding to each pixel. The first pixel group includes the pixels ax1 and ax1 every cycle in order from the top of the original drive waveform ODRV1.
x2, x6, x10,... correspond. The second to fourth pixel groups are also as illustrated.
As can be seen from FIGS. 35 and 38, when the number of the adjustment pixels is four, the pulse for recording the image pixel x1 is the second pulse of the ODRV1, but the number of the adjustment pixels is three. In this case, it is the first pulse of ODRV4. That is, the pulse for recording the image pixel x1 is advanced by 1/4 cycle. In FIG. 35, the wave to which the image pixel x1 is assigned in FIG. 38 is indicated by (x1) in parentheses. Although not shown in FIG. 35, as can be seen by comparing FIG. 35 with FIG. 38, the corresponding pulse is similarly advanced by 1/4 cycle for other image pixels after x2.

FIG. 39 shows a case where the number of adjustment pixels is three.
FIG. 4 is an explanatory diagram showing how each pixel in one raster is recorded. Nozzles n1, n
2, n3 and n4, as shown in FIG.
As shown in (b), (c), and (d), dots are sequentially recorded on the pixels. However, here, the image pixel x1 is recorded in the fourth main scan. As a result, the dot of the image pixel x1 is recorded as the fourth dot (from the left) following the three adjustment pixels on the paper P. In this way, the image pixel x1 is formed one pixel to the left as compared with the case of FIG. Here, the case where the number of the adjustment pixels is four and the case where the number of the adjustment pixels is three have been described. However, regardless of the number of the adjustment pixels, it is possible to form a dot using a plurality of original drive signals by the same procedure. it can.

As described above, in the third embodiment, since four original drive signals are generated by shifting the phase in quarter-period units and dots are formed by these, a single original drive signal is used. Dot can be recorded at a density four times higher than in the case of using. Here, the phase is 1
Although four original drive signals shifted by / 4 cycle are generated, any number of original drive signals may be generated. If N original drive signals (N is a natural number of 2 or more) are generated by shifting the phase by 1 / N cycle, the drive signal 1
Pixels can be recorded at N times higher density than in the case of a single pixel. This high-density pixel recording is possible regardless of the number of adjustment pixels. Further, if N is an even number, dots can be efficiently formed in both forward and backward movements when performing bidirectional printing in which dots are formed in the reciprocation of main scanning.

(7) Fourth Embodiment: The fourth embodiment is different from the first embodiment in the configuration of the print head 28, the head driving unit 113b, and the print data generation unit 103b. Other configurations are the same as in the first embodiment. The configuration of a drive signal generation unit (not shown) of the head drive unit 113b is the same as that of the second embodiment.

FIG. 40 is an explanatory diagram showing the arrangement of nozzles on the print head 28 and the delay data of each nozzle row.
In the fourth embodiment, a plurality of nozzles on the print head 28 are arranged in the sub-scanning direction as nozzle rows, and a plurality of nozzle rows are arranged in the main scanning direction. These nozzle rows are provided in two rows in a so-called staggered arrangement for each of black (K), cyan (C), magenta (M), light cyan (LC), light magenta (LM), and yellow (Y). . In the following, in FIG. 40, the columns on the left and the columns on the right are identified as K1 and K2, respectively, assuming that the left column is 1 and the right column is 2. Assuming that the print head 28 is fed from left to right in FIG. 40, the time when the nozzle row K2 reaches a specific pixel is longer than the time when K1 reaches the nozzle rows K1 and K2.
Earlier by a time tk2 corresponding to the interval of Similarly, the time when the nozzle array C1 reaches the pixel is determined by the nozzle arrays K1 and C1.
It is earlier by a time tc1 corresponding to one interval. The same applies to the other nozzle rows C2 to Y2. Therefore, if a drive signal is generated from pixel value data and supplied to each nozzle as it is, dots are formed at positions shifted in the main scanning direction by the interval of the nozzle rows even if ink is to be ejected to the same pixel. Will be done. Therefore, for the nozzle rows that reach the pixels before the nozzle row K1, the ink discharge positions are made to wait for the predetermined times tk2, tc1,..., Respectively, so that the ink discharge positions match.
Each nozzle row on the print head 28 is a nozzle row K1
Are spaced from each other by an integer multiple of four pixels.

FIG. 41 is an explanatory diagram showing functional blocks of a printing apparatus according to the fourth embodiment. In the printing apparatus of the fourth embodiment, the adjustment data distribution table AT is not provided on the computer PC side. Then, the printer driver 96
The print data generation unit 103b generates print data only from image pixels without distributing adjustment pixels. on the other hand,
On the printer PRT side, a delay data storage unit 118, an ejection characteristic data storage unit 114, and an adjustment data distribution table A
Tb.

FIG. 42 is an explanatory diagram showing a method of waiting for ejection of ink droplets based on delay data. Delay data storage unit 1
18, delay data Dk2 of each nozzle row other than K1
Dc1 to Dy2 are stored. These delay data are values indicating how many periods of the original drive signal the tk2, tc1,... Ty2 each correspond to. Since the nozzle rows are arranged at intervals of an integer multiple of four pixels, tk2, tc1,.
8 is an integral multiple of "the time when 8 passes through 4 pixels". On the other hand, one cycle of the original drive signal corresponds to “the time when the print head 28 passes through four pixels”, and thus the shift time tk of each nozzle row
2, tc1,... Are all numerical values divisible by the period of the original drive signal. Therefore, each delay data is an integer.
In the fourth embodiment, for example, Dk2 is 32 and Dc2
Is 176. As shown in FIG. 41, the delay data adjustment unit 119 (see FIG. 41), which is a functional unit of the CPU 41,
In the expansion buffer, a data portion in which dots are not formed by the number of the delay data is provided at the head of the pixel value data divided for each nozzle. As a result, the drive signal corresponding to the image pixel for each nozzle pixel is generated with a delay corresponding to the delay data. Therefore, even when ink is ejected to the same pixel from a nozzle row at a different position in the main scanning direction, ink is ejected to a correctly matched pixel.

Delay data adjusting section 119 (see FIG. 41)
In addition, prior to adding a data portion in which no dot is formed based on the delay data to the pixel value data, the delay data is adjusted according to the ejection characteristics of each nozzle (the amount of displacement of the dot formation position). The adjustment of the delay data for compensating the shift of the dot formation position is performed by increasing or decreasing the delay data in integer units. The delay data is a value indicating how many cycles of the original drive signal the difference tk2, tc1,... Ty2 of the arrival time of each nozzle reaches the pixel. Therefore, increasing or decreasing the delay data in integer units means adjusting the delay data in one cycle of the original drive signal. Register (serial data generation unit) 11
7 generates serial data based on the delay data thus adjusted and dot formation information for one pixel of each nozzle, and supplies the serial data to the head driving unit 113.

FIG. 43 is an explanatory diagram showing a method of correcting a dot formation position shift based on delay data. FIG. 44 is an explanatory diagram showing the state of the dot formation position shift. FIG.
FIG. 4 is an explanatory diagram showing a state of compensation of a dot formation position.
For example, in FIG.
In the case where dots are formed while transferring the dots, it is assumed that the dot formation position by the nozzle row C2 is shifted by four pixels to the right as shown in FIG. In FIG. 44, the drive waves indicated by broken lines mean that no dots are formed. Similarly, a circle indicated by a broken line in a pixel indicates that no dot is formed in that pixel. in this way,
When the dot formation position is shifted to the right by four pixels, the delay data adjustment unit 119 transfers the delay data Dc2 of the nozzle row C2 from 176 to 175 as shown in FIGS. 40 (a) and (b). cut back. By doing so, the driving waveform of the nozzle row C2 is advanced by one cycle. According to such a drive signal, the dot formation position is shifted to the left by four pixels, so that the dot is formed at a desired position as shown in FIG.

FIG. 46 is an explanatory diagram showing the state of the dot formation position shift. FIG. 47 is an explanatory diagram showing the state of the dot formation position compensation. In the above description, the case where the displacement amount of the dot formation is exactly four pixels corresponding to one wavelength of the original drive signal has been described. Here, the case where the dot displacement amount is one pixel will be described. As shown in FIG. 46, it is assumed that the dot formation position by the nozzle row C2 is shifted by one pixel to the right. In such a case, if the delay data Dc2 of the nozzle row C2 is reduced by one from 176 to 175, the driving waveform of the nozzle row C2 is also advanced by one cycle as shown in FIG. According to such a drive waveform, the dot formation position is shifted by four pixels to the left as compared with the case where the delay data Dc2 is 176. Therefore, as shown in FIG. 45, a dot is formed at a position shifted by three pixels to the left from the desired position.

The delay data adjustment unit 119 can handle only pixel data already assigned to each nozzle by the print data generation unit 103b. And the fourth
In this embodiment, since all the pixels in the raster are recorded in four main scans, the pixel data assigned to each nozzle is not continuous pixel data in the raster, but every three pixels (4
There is only one pixel of data). For this reason, the delay data adjustment unit 119 can correct the dot position deviation only in units of four pixels. Therefore, assuming that the number of original drive signals generated by the original drive signal generation unit is N, the delay data adjustment unit 11
No. 9 does not correct the fractional dot position deviation when the fraction obtained by dividing the dot position deviation by the pixel size is equal to or smaller than N / 2 pixels. If the fraction exceeds N / 2 pixels, the delay data is further corrected by one cycle. By doing so, the delay data adjustment unit 119
However, by correcting the delay data, it is possible to prevent the deviation of the dot formation position from increasing.

In the fourth embodiment, the CP on the printer PRT side
In U41, a process for compensating for a dot formation position shift is performed. Therefore, the processing can be performed at a higher speed than when the printer driver 96 performs the processing for compensating the dot formation position deviation. Although a case has been described above with an example in which the delay data D is reduced and the drive signal is advanced, the delay data adjustment unit 119 can increase the delay data D and delay the drive signal.

The present invention can be modified as follows. (I) In the above embodiments, an ink jet printer has been described. However, the present invention is not limited to an ink jet printer, and is generally applicable to various printing apparatuses that perform printing using a print head.

(Ii) In the above embodiment, part of the configuration realized by hardware may be replaced by software, and conversely, part of the configuration realized by software may be replaced by hardware. You may do so.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating a schematic configuration of a printing apparatus as an embodiment.

FIG. 2 is an explanatory diagram illustrating functional blocks of the printing apparatus.

FIG. 3 is an explanatory diagram illustrating a schematic configuration of a printer PRT.

FIG. 4 shows nozzles Nz in actuators 61 to 64
FIG. 4 is an explanatory view showing an array of the present invention.

FIG. 5 is an explanatory diagram showing a detailed structure of a piezo element PE and a nozzle Nz.

FIG. 6 is an explanatory diagram illustrating a state of a pixel printed by a printer PRT.

FIG. 7 is a flowchart of a print data generation processing routine.

FIG. 8 is an explanatory diagram showing a state of dots formed at appropriate timing.

FIG. 9 is an explanatory diagram showing a state of a dot formed by a nozzle in which a formation position is shifted.

FIG. 10 is an explanatory diagram showing a state of compensating for a shift in a dot formation position by adjusting image data.

FIG. 11 is an explanatory diagram showing a state in which a deviation of a dot formation position is compensated for by setting distribution of adjustment pixels.

FIG. 12 is an explanatory diagram illustrating an example of ejection characteristic data.

FIG. 13 is an explanatory diagram illustrating an example of an adjustment data distribution table.

FIG. 14 is an explanatory diagram illustrating an example of an adjustment pixel distribution table set based on black ink.

FIG. 15 is an explanatory diagram illustrating a state of correcting a shift amount by the printing apparatus according to the present embodiment.

FIG. 16 is a flowchart of a print data generation processing routine in another aspect.

FIG. 17 is an explanatory diagram showing a state in which an image is printed by an interlace method.

FIG. 18 is a flowchart of a print data generation processing routine according to the second embodiment.

FIG. 19 is an explanatory diagram illustrating a relationship between a moving direction of a carriage and a shift amount of a dot formation position.

FIG. 20 is an explanatory diagram showing a relationship between a moving direction of a carriage and compensation for a shift amount.

FIG. 21 is an explanatory diagram showing the contents of print data.

FIG. 22 is an explanatory diagram illustrating a print result when corrected pixel value data is used in a predetermined direction.

FIG. 23 is an explanatory diagram showing a printing result when corrected pixel value data is used in a direction opposite to a planned direction.

FIG. 24 is a flowchart illustrating a print execution routine when printing is performed using raster data for one pass sent to the expansion buffer 44;

FIG. 25 is an explanatory diagram showing the contents of modification of pixel value data used for forward movement using pixel value data corrected for backward movement.

FIG. 26 is an explanatory diagram illustrating a printer according to a modified example of the first embodiment.

FIG. 27 is an explanatory diagram illustrating a configuration of a functional block according to a second embodiment.

FIG. 28 is a flowchart of a dot formation timing adjustment process.

FIG. 29 is an explanatory diagram illustrating an example of a test pattern.

FIG. 30 is an explanatory diagram showing a test pattern for adjusting a relative positional relationship between black and cyan.

FIG. 31 is an explanatory diagram showing a relationship between a reference color when forming timing is adjusted and a color whose timing is to be adjusted.

FIG. 32 is an explanatory diagram illustrating functional blocks of the printing apparatus.

FIG. 33 is a block diagram showing a mechanism of a drive signal generation unit provided in a head drive unit.

FIG. 34 is an explanatory diagram showing how the pass decomposition unit 109 divides pixels in one raster into pixel groups.

FIG. 35 is a diagram showing in which period of each original drive waveform each pixel corresponds.

FIG. 36 is an explanatory diagram showing how each pixel in one raster is recorded.

FIG. 37 is an explanatory diagram showing how the pass decomposition unit 109 generates a pixel group when there are three adjustment pixels.

FIG. 38 is a diagram illustrating, in a case where the number of adjustment pixels is three, the number of cycles of each original drive waveform corresponding to each pixel.

FIG. 39 is an explanatory diagram showing how each pixel in one raster is recorded when the number of adjustment pixels is three.

FIG. 40 is an explanatory diagram showing the arrangement of nozzles on the print head and delay data of each nozzle row.

FIG. 41 is an explanatory diagram illustrating functional blocks of a printing apparatus according to a fourth embodiment.

FIG. 42 is an explanatory diagram showing a method of waiting for ejection of ink droplets based on delay data.

FIG. 43 is an explanatory diagram showing a method of correcting a dot formation position shift based on delay data.

FIG. 44 is an explanatory diagram showing a state of a dot formation position shift.

FIG. 45 is an explanatory diagram showing a state of compensation of a dot formation position.

FIG. 46 is an explanatory diagram showing a state of a dot formation position shift.

FIG. 47 is an explanatory diagram showing a state of compensation of a dot formation position.

[Explanation of symbols]

 14 ... Keyboard 23 ... Paper feed motor 24 ... Carriage motor 26 ... Platen 28 ... Print head 31 ... Carriage 32 ... Operation panel 34 ... Sliding shaft 36 ... Drive belt 38 ... Pulley 39 ... Position detection sensor 40 ... Control circuit 41 ... CPU 42 ... Programmable ROM (PROM) 43 ... RAM 44 ... Drive buffer 61 ... Actuator 61a ... Actuator 68 ... Ink passage 71,72 ... Ink cartridge 95 ... Application program 96 ... Printer driver 100 ... Input unit 101 ... Color correction processing unit 102 ... Halftone processing unit 103 print data generation unit 103a print data generation unit 104 output unit 105 normal print module 106 test pattern print module 107 test pattern data storage unit 108 Adjustment pixel number setting section 109 Path separation section 110 Input section 111 Main scanning section 112 Sub scanning section 113 Head driving section 113a Head driving section 113b Head driving section 114 Ejection characteristic data storage section 115 Receiving buffer Reference numeral 116: drive signal generation unit 117: register 118: delay data storage unit 119: delay data adjustment unit 120: pixel value data modification unit 121: adjustment pixel data generation unit

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toshihiro Hayashi 3-5-5 Yamato, Suwa-shi, Nagano Seiko Epson Corporation (72) Inventor Kazumitsu Shimada 3-5-5 Yamato, Suwa-shi, Nagano Seiko -F-term in Epson Corporation (reference) 2C056 EA11 EB59 EC07 EC12 EC28 EC34 EC74 EE02 FA04 FA11 2C062 LA03 LA09 2C480 CA17 CA55 EC11

Claims (16)

[Claims] A head having a plurality of nozzles for ejecting ink; a main scanning unit for performing main scanning in which the head reciprocates relative to a print medium in a predetermined direction; and a reciprocating path. A head driving unit that drives the head according to print data to form dots on at least a part of a plurality of pixels arranged in the main scanning direction; and the main scanning direction with respect to the head. A sub-scanning unit that performs sub-scanning that relatively sends the print medium in a sub-scanning direction that intersects with the control unit, and a control unit that controls printing.The print data includes an image for each nozzle of each main scan. Image pixel value data representing the dot formation state in the constituting image pixels,
Raster data having at least, sub-scan feed data representing the feed amount of the sub-scan feed performed after each main scan, and adjustment pixels that do not form dots used to adjust the position of the image pixels in the main scan direction Indicating the number of arrangements at both ends of the image pixel value data, adjustment pixel arrangement data configured as separate data from the raster data, and the control unit, of the route scheduled for each raster data A path reversal detection unit that detects that the direction is reversed, and the arrangement of the adjustment pixels is reversed with respect to the raster data in which the path is reversed with the image pixels interposed therebetween, and the image is arranged in accordance with the arrangement of the reversed adjustment pixels. By arranging the adjustment pixel value data indicating the existence of the adjustment pixel on at least one of both ends of the pixel value data, the raster Printing apparatus comprising a raster data reconstruction unit for reconstructing an over data, the. 2. The printing apparatus according to claim 1, wherein the raster data before the reconstruction further includes, as at least a part of the adjustment pixel value data, an adjustment pixel having the same format as the image pixel value data. A printing device having data. 3. The printing apparatus according to claim 1, wherein each of the raster data further includes a round-trip flag indicating a direction of a route scheduled for each of the raster data.
Printing device. 4. The printing apparatus according to claim 1, wherein the head is a head that forms a multi-color dot by ejecting a predetermined color ink for each nozzle, and the adjustment pixel arrangement data. The printing device, wherein the number of adjustment pixels is independently determined for each color of the ink. 5. The printing apparatus according to claim 1, wherein the plurality of nozzles are further divided into a plurality of nozzle rows extending in the sub-scanning direction, and the plurality of nozzle rows are main-scanned. The printing apparatus, wherein the number of adjustment pixels in the adjustment pixel arrangement data is determined independently for each nozzle row. 6. The printing apparatus according to claim 1, wherein the number of adjustment pixels in the adjustment pixel arrangement data is determined independently for each of the nozzles. 7. A head having a plurality of nozzles for ejecting ink performs main scanning reciprocating relative to a print medium in a predetermined direction, and a sub-scanning direction intersecting the main scanning direction with respect to the head. A sub-scan is performed to relatively send the print medium in a scanning direction, and the head is driven in accordance with print data in both of the reciprocating paths, at least a part of a plurality of pixels arranged in the main scanning direction. A print control device that generates the print data, which is supplied to a printing unit that forms dots on the print control unit, wherein the print data includes, for each nozzle of each main scan, a dot of an image pixel forming an image. Image pixel value data representing the formation state
Raster data having at least, sub-scan feed data representing the feed amount of the sub-scan feed performed after each main scan, and adjustment pixels that do not form dots used to adjust the position of the image pixels in the main scan direction Indicates the number of arrangements at both ends of the image pixel value data, and includes adjustment pixel arrangement data configured as data different from the raster data. The print control device includes: a direction of a path scheduled for each raster data; A path reversal detection unit that detects that the path has been reversed, and the arrangement of the adjustment pixels is reversed with respect to the raster data in which the path has been reversed, with the image pixels interposed therebetween, and the image pixels according to the arrangement of the reversed adjustment pixels. By arranging adjustment pixel value data representing the existence of the adjustment pixel on at least one of both ends of the value data, Print control apparatus comprising: a raster data reconstruction unit for reconstructing the data. 8. The print control apparatus according to claim 7, wherein the raster data before the reconstruction further includes, as at least a part of the adjustment pixel value data, an adjustment in the same format as the image pixel value data. A print control device having pixel data. 9. The print control device according to claim 7, wherein each of the raster data further includes a round-trip flag indicating a direction of a route scheduled for each of the raster data.
Print control device. 10. A head having a plurality of nozzles for ejecting ink performs main scanning reciprocating relative to a print medium in a predetermined direction, and a sub-intersecting head intersecting the main scanning direction with respect to the head. A sub-scan is performed to relatively send the print medium in a scanning direction, and the head is driven in accordance with print data in both of the reciprocating paths, at least a part of a plurality of pixels arranged in the main scanning direction. (A) raster data having at least image pixel value data representing a dot formation state in an image pixel forming an image for each nozzle of each main scan; Sub-scan feed data representing the feed amount of the sub-scan feed performed after the main scan, and an adjustment image that does not form a dot used to adjust the position of the image pixel in the main scan direction Of indicates the arrangement number in both ends of the image pixel value data, and generating the print data including a configured adjusted pixel arrangement data as separate data from said raster data, (b)
Driving the head in accordance with the print data to form dots in both reciprocating paths; (c) detecting that the direction of the path planned for each raster data is reversed; The arrangement of the adjustment pixels is reversed with respect to the raster data whose path is reversed with the image pixels interposed therebetween, and at least one of both ends of the image pixel value data according to the arrangement of the reversed adjustment pixels. Reconfiguring the raster data by arranging the adjusted pixel value data indicating the existence of the raster data. 11. The printing method according to claim 10, wherein in the step (a), as at least a part of the adjustment pixel value data, adjustment pixel data having the same format as the image pixel value data is generated. And a printing method. 12. A printing method according to claim 10, wherein said step (a) includes a step of providing a reciprocating flag indicating a direction of a route scheduled for each raster data in said raster data. Method. 13. The printing method according to claim 10, wherein the step (b) includes a step of discharging a predetermined color ink for each nozzle to form multicolor dots, and the step (a). The printing method includes a step of independently determining the number of adjustment pixels of the adjustment pixel arrangement data for each color of the ink. 14. The printing method according to claim 10, wherein the step (b) is divided into a plurality of nozzle rows extending in the sub-scanning direction, and the plurality of nozzle rows are divided in the main scanning direction. Forming a dot using nozzles arranged along the line, wherein the step (a) includes a step of independently determining the number of adjustment pixels of the adjustment pixel arrangement data for each nozzle row , Printing method. 15. The printing method according to claim 10, wherein the step (a) includes a step of independently determining the number of adjustment pixels of the adjustment pixel arrangement data for each nozzle. 16. A head having a plurality of nozzles for ejecting ink performs a main scan reciprocating relative to a print medium in a predetermined direction, and a sub-intersecting the head with the main scan direction. A sub-scan is performed to relatively send the print medium in a scanning direction, and the head is driven in accordance with print data in both of the reciprocating paths, at least a part of a plurality of pixels arranged in the main scanning direction. A recording medium on which a computer program for causing a computer provided with a printing device to form dots on the computer to perform printing is recorded, and for each nozzle of each main scan, formation of dots in image pixels constituting an image Image pixel value data representing the state
Raster data having at least, sub-scan feed data representing the feed amount of the sub-scan feed performed after each main scan, and adjustment pixels that do not form dots used to adjust the position of the image pixels in the main scan direction A function of generating print data including adjustment pixel arrangement data, which indicates the number of arrangements at both ends of the image pixel value data and is separate data from the raster data; and A function of driving the head in accordance with data to form dots, a function of detecting that the direction of the path scheduled for each raster data has been reversed, and a function of the adjustment pixel for the raster data in which the path has been reversed. The arrangement is reversed with the image pixel interposed therebetween, and both ends of the image pixel value data are arranged in accordance with the arrangement of the inverted adjustment pixel. At least one, said by arranging an adjustment pixel value data indicating the existence of adjustment pixels, for realizing a function for reconstructing the raster data, a recording medium recording the computer program.