JP2006082528A - Dot pattern assigning method and device, printer, program and data structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a matter of existing technology that occurrence of unevenness in density or a new streak is inevitable when a new defective nozzle occurs during operation. <P>SOLUTION: (a) When a plurality of arrays of line heads capable of ejecting ink of the same color and density are arranged on a print head, and (b) one pixel is composed of a dot pattern of n row×n column (n is a natural number of 2 or above) and represented with a resolution equal to 1/n of nozzle pitch, (c) the number of dots being assigned to each line head is determined such that the number of dots composing one pixel are assigned uniformly or substantially uniformly to the line head of m columns (m is a natural number of 2 or above) in the dot pattern assigning method. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

One aspect of the invention relates to a dot pattern assignment method for a line head that ejects ink having the same color and density. One embodiment of the present invention relates to a dot pattern assignment apparatus and a printing apparatus that realize this assignment method.
Another embodiment of the present invention relates to a program and a data structure that realize the same function.

Currently, the ink jet method is used for various types of printing. For example, the recording medium includes paper, cloth (including non-woven fabric), plastic, wood and the like.
In the case of the ink jet system, there is a considerable possibility that density unevenness and streaks occur due to defective nozzles (for example, malfunctioning nozzles, non-ejection nozzles) and other causes. For this reason, establishment of a processing technique in consideration of the presence of defective nozzles is required.
For example, Patent Document 1 discloses a method of generating a thinning pattern so that a defective nozzle is not used for printing in a multi-pass recording method in which one recording area is printed by a plurality of scans.
JP 2004-042439 A

By the way, this processing technique needs to know the position of the defective nozzle in advance. For this reason, when a new defective nozzle is generated during operation, density unevenness and streaks are newly generated.
Therefore, even when a new defective nozzle is generated during operation, it is required to establish a processing technique capable of suppressing new generation of density unevenness and streaks.

The inventor pays attention to the above technical problem and proposes the following technical technique.
First, it is assumed that a print head in which a plurality of line heads capable of ejecting ink having the same color and density are arranged can be used.
In addition, one pixel is constituted by a dot pattern of n rows × n columns, and one pixel is expressed with a resolution of 1 / n of the nozzle pitch.
In this case, in one aspect of the invention, the number of dots constituting one pixel is assigned to each line head so that the number of dots is evenly or substantially evenly assigned to the line heads of m columns (m is a natural number of 2 or more). A processing method for determining the number of assigned dots is applied.
For example, if one pixel is configured with a dot pattern of 2 rows × 2 columns (that is, configured with 4 dots), a process of equally allocating 4 dots to a plurality of columns of line heads Apply the method. Various combinations can be considered as to which dot pattern is assigned to which line head.

In another aspect of the invention, in a pixel range given by k rows × k columns (k is a natural number of 2 or more), the number of dots constituting the pixel range is m columns (m is a natural number of 2 or more). The number of dots allocated to each line head is determined so that the line heads are allocated equally or almost equally to the line heads.
For example, in a pixel range of 2 pixels × 2 pixels, a processing method that equally assigns dots constituting four pixels to a plurality of lines of line heads is applied. Here, if one pixel is constituted by a dot pattern of 2 rows × 2 columns (that is, constituted by 4 dots), 16 dots are equally allocated to a plurality of lines of line heads. Apply processing method.
Of course, various combinations can be considered as to which dot pattern is assigned to which line head. For example, a method of controlling dots assigned to each line head on a pixel basis can be considered. Further, for example, a method of controlling in units of individual dots can be considered.

In the present specification, the line head refers to a head in which a plurality of nozzles that eject ink are arranged in a line.
In addition to the head in which nozzles are arranged at the same density as the maximum resolution over the print width, the line head is relatively moved in the direction (main scanning direction) perpendicular to the moving direction of the recording medium (sub-scanning direction). That are mounted on a print head of a certain type.
The above-described technique is not limited to the dot pattern assignment method, but can be realized as a dot pattern assignment device, a printing device, a program, and a data structure. A specific example will be described later.

  If the technical method which concerns on invention is used, the dot pattern which comprises one pixel will be formed using the some nozzle mounted in the some line head. As a result, even if a new defective nozzle is generated during operation, other dot patterns constituting one pixel are formed using other normal nozzles, so density unevenness and streaks in one pixel region are observed. It can be made difficult.

Hereinafter, embodiments of the technical technique according to the invention will be described.
In addition, the well-known or well-known technique of the said technical field is applied to the part which is not illustrated or described in particular in this specification.
The embodiment described below is one embodiment of the present invention and is not limited thereto.

(A) Configuration Example of Print Head First, the configuration of the print head will be briefly described. In this embodiment, a line head in which nozzles are arranged at the same density as the maximum resolution over the print width is used as the print head. The print head can be attached to and detached from the main body (housing) of the printing apparatus.
The print head has a slot for attaching / detaching an ink cartridge loaded with ink. An opening for guiding ink to the nozzle is formed at the bottom of each slot. The opening is connected to the corresponding nozzle group through the flow path. Accordingly, ink is supplied from the ink cartridge to the nozzle group through the opening and the flow path.

FIG. 1A shows a configuration example of the nozzle surface 1 of the print head. On the nozzle surface 1 according to this embodiment, two rows of nozzle groups N1 and N2 are arranged in the moving direction of the recording medium. Each of the nozzle groups N1 and N2 corresponds to a line head.
In each nozzle group, the nozzle 1A is arranged over the same length as the printing width at the same density as the highest resolution. In this embodiment, the nozzle pitch is 600 dpi. The nozzle groups N1 and N2 correspond to the same type of ink. That is, it corresponds to the same color and the same density of ink.

FIG. 1B shows an example of a correspondence relationship between pixels and nozzles. FIG. 1B shows a case where pixels are formed with half the nozzle pitch, in this case, with a resolution of 300 dpi. A range surrounded by a broken line corresponds to one pixel.
In this case, one pixel is formed by four dots. Four dots are formed using the nozzle groups N1 and N2 equally. In the case of FIG. 1, four nozzles surrounded by a solid line 1C are used to form one pixel 1B.

(B) Effect of uniform ejection of ink droplets using a plurality of nozzle groups By distributing the number of ejections of ink droplets used for forming one pixel evenly to the two front and rear nozzle groups N1 and N2, the following Can be expected.
First, the ejection of ink to a vertical line, which is the moving direction of the recording medium, is shared by the front and rear nozzle groups. For this reason, even if a defective nozzle occurs in one nozzle group, the influence can be compensated for by the other nozzle group.
Accordingly, it is possible to suppress density unevenness and streaks that have been observed when only one nozzle group is used.
FIG. 2 shows an example of printing when one pixel is formed using one nozzle group. In the drawing, the circles with hatching indicate dots formed by ink droplets ejected from the corresponding nozzles. The numbers in the circles represent nozzle groups that eject ink droplets that form dots. In the case of FIG. 2, since only one nozzle group is used, only the numeral “1” is shown. “O” represents an odd-numbered nozzle, and “E” represents an even-numbered nozzle. As described above, even when one pixel is printed using a plurality of nozzles, when only one nozzle group is used, a streak 3 due to insufficient ejection or a streak 5 due to non-ejection is confirmed.

FIG. 3 shows a printing example according to the embodiment. The notation method is basically the same as in FIG. In the case of FIG. 3, dots are formed by using two nozzle groups alternately in the moving direction of the recording medium. For this reason, “1” and “2” are written in the circles representing dots, and the difference in the nozzle group used for printing is distinguished.
In the case of FIG. 3, one pixel is printed using four nozzles. Therefore, even if ejection failure or non-ejection occurs in one of the nozzles used in the configuration of one pixel, the other three dots can be formed in a normal state.
Therefore, as shown in regions 7 and 9, defective dots or missing dots do not continue in the moving direction of the recording medium. As a result, the image quality is improved as compared with the case of FIG. Also, since one pixel is expressed using four dots, there is little change in gradation.

Further, in the case of this printing method, even if there is a dot shift depending on the positional relationship between the two nozzle groups N1 and N2 positioned forward and backward with respect to the moving direction of the recording medium, a relative pixel shift may occur. Absent.
Actually, even if there is a head mounting error or a recording medium feeding error, the pixel size is doubled in each of the nozzle arrangement direction and the recording medium moving direction. Is half that of forming one dot. Therefore, it is possible to suppress the occurrence of moire (interference fringes) due to pixel positional deviation.
Further, the ejection of ink from each nozzle group alternates with respect to the moving direction of the recording medium. For this reason, the average driving period of each nozzle is doubled, and the time margin until the ink is refilled in the liquid chamber below the nozzle can be increased. As a result, the liquid level in the liquid chamber is stabilized. This is advantageous for stable ink ejection, and is effective in reducing malfunction nozzles.

(C) Example of dot pattern assignment Here, an example of dot pattern assignment that equalizes the output opportunities of the two nozzle groups N1 and N2 when each pixel is configured by 2 × 2 dots will be described.
(1) Assignment example 1
FIG. 4 is the same as the allocation example shown in FIG. In this example, the dots corresponding to the two nozzle groups N1 and N2 are arranged so as to form a checkered pattern over a plurality of pixels. That is, the same pattern is repeated for all pixels, and dots corresponding to the nozzle groups N1 and N2 appear alternately in both the nozzle arrangement direction and the recording medium movement direction.
In the case of this arrangement example, as described above, the influence of defective nozzles generated in one nozzle group can be halved.
In the case of this allocation example, four dots are equally allocated to two nozzle groups in units of one pixel.

(2) Allocation example 2
FIG. 5 shows another example of assignment. In this allocation example, dots corresponding to the nozzle groups N1 and N2 appear alternately in the moving direction of the recording medium. This is the same as allocation example 1.
However, the arrangement direction of the nozzles is different from the allocation example 1. That is, in the case of FIG. 5, the dots corresponding to the nozzle groups N1 and N2 are different in that they appear alternately in units of pixels. For example, in the case of the top row in FIG. 5, each dot appears as “1”, “1”, “2”, “2” in order from the left end, and is repeated below.
In other words, in the case of this allocation example, different allocation patterns in units of pixels appear alternately in the nozzle arrangement direction, while dots corresponding to the nozzle groups N1 and N2 appear alternately in the moving direction of the recording medium. . Note that the same pattern continues in pixel units in the moving direction of the recording medium.
As a result, the same allocation pattern repeatedly appears in the nozzle arrangement direction and the recording medium moving direction, not only within the pixels, but also in units of four pixels given in 2 rows × 2 columns.
These four pixel ranges are called basic blocks. In this allocation example, each dot is equally allocated to the nozzle groups N1 and N2 in the basic block.

(3) Allocation example 3
FIG. 6 shows another example of assignment. This allocation example has a relationship in which the direction of the allocation pattern in allocation example 2 is switched. That is, the dots corresponding to the nozzle groups N1 and N2 appear alternately in the nozzle arrangement direction. On the other hand, the dots corresponding to the nozzle groups N1 and N2 appear alternately in pixel units in the moving direction of the recording medium.
Therefore, in the case of this allocation example, the influence of the defective nozzle cannot be interpolated with other normal nozzles in the same pixel. However, in the pixel unit, dots are alternately formed by the other nozzle group. For this reason, the influence of the defective nozzle is halved, and an improvement in image quality can be realized.
In this case as well, the same assignment pattern repeatedly appears in the nozzle arrangement direction and the recording medium movement direction in units of four pixels given in 2 rows × 2 columns as well as in the pixels. Also in this case, each dot is equally allocated to the nozzle groups N1 and N2 in the basic block.

(4) Assignment example 4
FIG. 7 shows another example of assignment. This allocation example is a modified pattern of allocation example 1. In this allocation example, the dot pattern in the pixel is reversed horizontally for each pixel in the nozzle arrangement direction and the recording medium movement direction.
That is, in the case of the uppermost stage in FIG. 7, each dot appears as “1”, “2”, “2”, “1” in order from the left end, and repeats thereafter. Further, in the case of the left end in FIG. 7, each dot appears as “1”, “2”, “2”, “1” in order from the top, and the following is repeated.
In this case as well, the same assignment pattern repeatedly appears in the nozzle arrangement direction and the recording medium movement direction in units of four pixels given in 2 rows × 2 columns as well as in the pixels. Also in this case, each dot is equally allocated to the nozzle groups N1 and N2 in the basic block.

(5) Allocation example 5
FIG. 8 shows another example of assignment. This allocation example is an example in which the pixels associated with the nozzle groups N1 and N2 are alternately switched in correspondence with the nozzle groups N1 and N2 in units of pixels, with respect to the nozzle arrangement direction and the recording medium movement direction.
In the example of FIG. 8, all the four dots constituting the pixel in the upper left corner are formed by the nozzle group N1. Further, all four dots constituting the right and lower pixels are formed by the nozzle group N2.
In this case, mutual interpolation within the pixel cannot be expected, but the same allocation pattern repeatedly appears in the nozzle arrangement direction and the recording medium moving direction in units of four pixels given in 2 rows × 2 columns. Also in this case, each dot is equally allocated to the nozzle groups N1 and N2 in the basic block.

(D) Embodiment 1 of printing apparatus
FIG. 9 shows a circuit configuration example of the printing apparatus 11 that realizes the printing method described above.
It is assumed that the printing apparatus 11 is equipped with a print head having the nozzle configuration shown in FIG. That is, it is assumed that the printing apparatus 11 is equipped with a print head having a nozzle pitch of 600 dpi. FIG. 9 shows a circuit configuration of a signal processing unit used when reproducing an image with a resolution of 300 dpi.
The printing apparatus 11 includes an input image buffer 13, a luminance / density conversion unit 15, a gamma conversion unit 17, a halftoning unit 19, a dot pattern assignment unit 21, and a head drive circuit 23.

In the case of this embodiment, the function as a print control unit is provided by at least the dot pattern allocation unit 21.
Among these, the input image buffer 13 is a storage device that temporarily stores characters, images, and other print data. For example, a semiconductor memory or a hard disk is used. In the case of monochrome printing, the print data is given as luminance data corresponding to each pixel.
The luminance / density conversion unit 15 is a processing device that converts luminance values into 256-level density data.
The gamma conversion unit 17 is a processing device that corrects density data according to gamma characteristics. The gamma converter 17 converts density data according to the ink amount, the material of the recording medium, and the like.

The halftoning unit 19 is a processing device that reduces the density data after gamma correction to the number of gradations suitable for expression by dots. In this embodiment, density data of 256 gradations is reduced to 2 gradations. This is because the density is expressed by the presence or absence of dots.
FIG. 10 shows a circuit configuration example of the halftoning unit 19. The halftoning unit 19 includes an error diffusion processing unit 19A and a quantization unit 19B.
Here, the adder 19A1 functions as a calculator that adds the correction value to the density data. This addition processing corresponds to correction processing for diffusing previously generated quantization errors to surrounding pixels. The correction value is given from the error buffer 19A2.

The density data in which the quantization error is corrected is compared with the threshold value TH in the binarization thresholding unit 19A3 and converted to either “0” or “255”. That is, the binarization thresholding unit 19A3 rounds the details of the density data.
A part of the rounded density data is converted into “0” or “1” in the quantization unit 19B. Here, “0” represents no dot, and “1” represents the presence of a dot.
A part of the density data after the rounding process is subtracted from the value before the rounding process in the subtractor 19A4. This subtraction process corresponds to the quantization error calculation process.
The calculated quantization error is multiplied by the error diffusion coefficient in the multiplier 19A5, and the multiplication result is stored in the error buffer 19A2 as a correction value. The above is the processing content executed by the halftoning unit 19.

The dot pattern assignment unit 21 is a processing device that converts a dot pattern corresponding to binary density data. The quantized value input to the dot pattern assignment unit 21 is temporarily stored in the binary data buffer 21A and then provided to the dot distribution unit 21B.
The dot distribution unit 21B refers to the pattern table 21C and executes a process of assigning a dot pattern suitable for binary density data.
Here, dot patterns corresponding to density data “1” and “0” are stored in the pattern table 21C. In this embodiment, FIGS. 11A and 11B are stored as dot patterns corresponding to density data “1”. FIG. 11A is for the nozzle group N1, and FIG. 11B is for the nozzle group N2.

On the other hand, patterns shown in FIGS. 11C and 11D are stored as dot patterns corresponding to density data “0”. FIG. 11C is for the nozzle group N1, and FIG. 11D is for the nozzle group N2. Such a dot pattern is temporarily stored in the drive data buffer 21D and then applied to the head drive circuit 23.
The head drive circuit 23 is a processing device that drives the corresponding nozzle groups based on the drive data read from the drive data buffer 21D. That is, the head drive circuit 23 operates to eject ink droplets from the nozzles at positions corresponding to the drive data. Thus, an image is printed on the recording medium at a resolution of 300 dpi.

(E) Embodiment 2 of printing apparatus
FIG. 12 shows a circuit configuration example of the printing apparatus 31 that realizes the printing method described above.
In this embodiment, a case where the distribution process of the dot pattern allocation unit 33 is realized by software processing will be described. Therefore, the same circuit configuration as that of FIG. 10 is used except for the dot pattern assignment unit 33.
The dot pattern allocation unit 33 includes a binary data buffer 33A, a dot distribution unit 33B, a pattern table 33C, and a drive data buffer 33D. These components are the same as in FIG.
The difference is that the sorting process of the dot sorting unit 33B is performed according to the processing procedure described below, and there is one dot pattern stored in the pattern table 33C.

First, the dot distribution unit 33B generates a read pointer for the binary data buffer 33A by the following method. FIG. 13 shows the relationship between the readout pointer and each pixel. The resolution of the print image is 300 dpi, but the presence or absence of dots must be assigned at a resolution of 600 dpi. Therefore, the pixel readout pointer (Pm, Pn) is given as (X / 2, Y / 2) using dot coordinates (X, Y).
In the case of FIG. 13, the pixel density data given by the readout pointer (3, 3) is “1”. Further, the density data of the pixel given by the read pointer (4, 3) is “1”. Similarly, the density data of the pixel given by the read pointers (3, 4) and (4, 4) is “0”.

Next, the dot distribution unit 33B generates a read pointer for the pattern table 33C by the following method. FIG. 14 shows the relationship between the read pointer and the pattern values stored in the pattern table 33C.
Incidentally, FIG. 14 shows pattern values in units of 16 dots. Here, the description will be made on the assumption of the dot pattern shown in FIG.
First, the structure of the pattern table 33C will be described. The pattern table 33C is managed as 16 areas. Each area is given a mask number (MASK0 to 15). The read pointer designates this mask number.

The dot distribution unit 33B determines a mask number corresponding to the dot coordinates (X, Y) by the following equation.
Mask number = 4 * (2 * ((Y% 4) / 2) + (Y% 2)) + 2 * ((X% 4) / 2) + X% 2
In the preceding equation, the operator% means obtaining the remainder of the division operation. For example, if “5% 2”, “1” is a desired value. In this example of dividing by 2, the value given by the operator% is either “0” or “1”.
In the previous equation, the operator / means obtaining the quotient of the division operation. For example, if “3/2”, “1” is the value to be obtained.

FIG. 14 shows the relationship between each area (MASK0 to 15) and the calculation term.
Here, the first term of the previous equation is an equation that determines which row of 4 rows × 4 columns corresponds to the value obtained by normalizing the parameter Y. In the first term, “2 * ((Y% 4) / 2)” determines whether it corresponds to the upper 2 rows or the lower 2 rows of 4 rows × 4 columns shown in FIG. It is a formula. In the first term, “Y% 2” is an expression that determines whether the first line or the second line of the two lines determined by the previous expression.
With this formula, the position when the Y coordinate is normalized is determined. That is, it is determined which line is “0”, “4”, “8”, or “12”.
Next, the second and third terms of the previous formula will be described. These two terms are equations for determining the position when the X coordinate is normalized. First, the second term is an equation for determining either the left two columns or the right two columns. The third term is an expression for determining whether the determined two columns are the right side or the left side.
With this formula, the position when the X coordinate is normalized is determined. In other words, “0”, “1”, “2”, or “3” is determined.

With this procedure, the dot distribution unit 33B determines a read pointer for the pattern table 33C. When the reading pointer is determined, the reading of the pattern value stored at the corresponding position and the calculation process of the drive data corresponding to each nozzle group are executed.
In each area, as shown in FIG. 14, a value “1” or “0” corresponding to the adopted dot pattern is stored in association with the mask number.
Here, the pattern value “1” means the ON control of the nozzle group N1 and the OFF control of the nozzle group N2, and the portion with the pattern value “0” indicates the OFF control of the nozzle group N1 and the nozzle group N2. Means on-control of
Therefore, actual drive data is determined by the logical product of these pattern values and density data. However, the nozzle group N2 is determined by the logical product of the logical inversion value of the pattern value and the density data.

For example, when the nozzle coordinates (X, Y) correspond to the mask number “0” and the density data is given as “1”, the drive data for the nozzle group N1 is calculated by “density data * pattern value”. As a result, “1” is obtained. On the other hand, the drive data for the nozzle group N2 at the same position is “0” as a result of the calculation of “density data * logically inverted value of pattern value (0)”.
Similarly, the drive data for the nozzle group N1 corresponding to the mask number “1” is “0” as a result of the calculation of “density data * pattern value”. The drive data for the nozzle group N2 corresponding to the mask number “1” is “1” as a result of the calculation of “density data * logically inverted value of pattern value (1)”.

In the case of mask numbers 8 to 15, since the density data is “0”, both the drive data for the nozzle group N1 and the drive data for the nozzle group N2 are “0”.
This calculation result coincides with FIG. 11 described in the above embodiment. Thus, the drive data can be determined by software processing. In this case, only one type of dot pattern is stored in the pattern table 33C.

(F) Other Embodiments (a) In the case of the above-described example, it has been described that one type of dot pattern is stored in the pattern table.
However, a plurality of dot patterns can be stored in the pattern table. In this case, which dot pattern is to be referred to may be selected before execution of the printing process in accordance with the print contents and user settings.
(B) In the case of the above-described embodiment, the case where two line heads capable of ejecting ink of the same color and the same density are mounted on the print head has been described.
However, the technology according to the invention can also be applied when three or more rows of line heads are mounted on the print head.

(C) In the case of the above-described embodiment, the case where one pixel is expressed by a total of four dots given by 2 rows × 2 columns has been described. That is, the case where the image is expressed with a resolution of 1/2 the nozzle pitch has been described.
However, the present invention can also be applied to a case where one pixel is expressed by a total of n 2 dots given by n rows × n columns (n is a natural number of 3 or more).
(D) In the case of the above-described embodiment, the basic block is defined by a total of four pixels of 2 rows × 2 columns.
However, the basic block may be defined by a total of k 2 pixels given by k rows × k columns (k is a natural number of 3 or more).

(E) In the case of the above-described embodiment, the case where the line heads are arranged over the same length as the printing width at the same density as the maximum resolution has been described. This type of line head is also called a fixed head.
However, the line head can also be applied when mounted on a head that is serially driven with respect to a recording medium. This type of line head is also called a multi-head. In this case, the nozzle arrangement direction used in the description of the embodiment may be read as the main scanning direction, and the recording medium moving direction may be read as the sub-scanning direction.
(F) The ink of the same color and the same density in the foregoing embodiment may be not only black ink but also color ink (magenta ink, cyan ink, yellow ink).

(G) In the above-described embodiment, the case where one dot is formed by one ink droplet has been described, but one dot may be formed by a plurality of ink droplets.
By configuring one dot with a plurality of dots, it is possible to further enhance the gradation expression ability by changing the dot diameter or changing the density.
(H) In the above embodiments, the dot diameters are all assumed to be the same, but the dot diameter may be varied by adjusting the ink droplet amount.
Further, the dot diameter may be varied according to the ink density. By changing the dot diameter, the gradation expression ability can be further enhanced.

(I) The printing apparatus in the above-described embodiment may be a dedicated printing machine or a multifunction machine having other functions. In addition, the usage of the printing apparatus is not limited to the premise for use in an office or home, but includes medical usage. For example, the present invention can be applied to printing of an appearance image of an affected area, an X-ray image, an echo image, and other medical images.
(J) In the above-described embodiment, the signal processing in the printing apparatus has been described in hardware. However, when the signal processing in the printing apparatus is defined by firmware or an execution program, each signal processing is realized by software. You may do it.
The execution program is preferably stored in a semiconductor memory, hard disk, optical storage medium, or other storage medium.
(K) Various modifications can be considered in the above-described embodiments within the scope of the gist of the invention. Various modifications and application examples created based on the description of the present specification are also conceivable.

It is a figure which shows the structural example of a nozzle surface. FIG. 10 is a diagram illustrating a printing example in the case where one pixel is formed of a plurality of dots and all the dots are formed by one line head. FIG. 6 is a diagram illustrating a printing example in the case where one pixel is configured with a plurality of dots and each dot is equally allocated to a plurality of lines of line heads. It is a figure which shows the example of the allocation relationship between a some dot and each line head. It is a figure which shows the example of the allocation relationship between a some dot and each line head. It is a figure which shows the example of the allocation relationship between a some dot and each line head. It is a figure which shows the example of the allocation relationship between a some dot and each line head. It is a figure which shows the example of the allocation relationship between a some dot and each line head. It is a figure which shows the structural example of a printing apparatus (dot pattern allocation apparatus). It is a figure which shows the structural example of a halftoning part. It is a figure which shows the example of a dot pattern stored in the pattern table. It is a figure which shows the other structural example of a printing apparatus (dot pattern allocation apparatus). It is a figure which shows the determination method of the read pointer of a binary data buffer. It is a figure which shows the determination method of the read pointer of a pattern table.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Nozzle surface 1A Nozzle 11 Printing apparatus 13 Input image buffer 15 Luminance / density conversion part 17 Gamma conversion part 19 Halftoning part 21, 33 Dot pattern allocation part 21A, 33A Binary data buffer 21B, 33B Dot distribution part 21C, 33C pattern Table 21D, 33D Drive data buffer 23 Head drive circuit

Claims (11)

When the line head capable of ejecting ink of the same color and density is arranged in a plurality of rows on the print head,
When one pixel is composed of a dot pattern of n rows × n columns (n is a natural number of 2 or more) and one pixel is expressed with a resolution of 1 / n of the nozzle pitch,
The number of dots allocated to each line head is determined so that the number of dots constituting one pixel is equally or substantially evenly allocated to line heads of m columns (m is a natural number of 2 or more). Dot pattern assignment method. When the line head capable of ejecting ink of the same color and density is arranged in a plurality of rows on the print head,
When one pixel is composed of a dot pattern of n rows × n columns (n is a natural number of 2 or more) and one pixel is expressed with a resolution of 1 / n of the nozzle pitch,
In a pixel range given by k rows × k columns (k is a natural number of 2 or more), the number of dots constituting the pixel range is equal or almost equal to a line head of m columns (m is a natural number of 2 or more). A dot pattern assigning method, wherein the number of dots assigned to each line head is determined so as to be assigned to each line head. The dot pattern allocation method according to claim 2,
A dot pattern assigning method, wherein a dot pattern of n rows × n columns constituting one pixel is assigned to one line head. Line heads capable of ejecting ink of the same color and density are arranged in a plurality of rows on the print head,
When one pixel is composed of a dot pattern of n rows × n columns (n is a natural number of 2 or more) and one pixel is expressed with a resolution of 1 / n of the nozzle pitch,
A dot pattern assigning unit that determines the number of dots to be assigned to each line head so that the number of dots constituting one pixel is equally or substantially evenly assigned to line heads of m columns (m is a natural number of 2 or more). A dot pattern assigning device. When the line head capable of ejecting ink of the same color and density is arranged in a plurality of rows on the print head,
When one pixel is composed of a dot pattern of n rows × n columns (n is a natural number of 2 or more) and one pixel is expressed with a resolution of 1 / n of the nozzle pitch,
In a pixel range given by k rows × k columns (k is a natural number of 2 or more), the number of dots constituting the pixel range is equal or almost equal to a line head of m columns (m is a natural number of 2 or more). And a dot pattern assigning unit that determines the number of dots assigned to each line head. A line head capable of ejecting ink of the same color and density, a print head arranged in a plurality of rows on the print head; and
When one pixel is composed of a dot pattern of n rows × n columns (n is a natural number of 2 or more), and one pixel is expressed with a resolution of 1 / n of the nozzle pitch, the number of dots constituting one pixel Comprises a dot pattern assigning unit that determines the number of dots assigned to each line head so that the line heads are assigned equally or substantially evenly to line heads of m columns (m is a natural number of 2 or more). Printing device. A line head capable of ejecting ink of the same color and density, a print head arranged in a plurality of rows on the print head; and
When one pixel is composed of a dot pattern of n rows × n columns (n is a natural number of 2 or more) and one pixel is expressed with a resolution of 1 / n of the nozzle pitch,
In a pixel range given by k rows × k columns (k is a natural number of 2 or more), the number of dots constituting the pixel range is equal or almost equal to a line head of m columns (m is a natural number of 2 or more). A dot pattern allocating unit that determines the number of dots allocated to each line head. A computer that functions as a print control device that controls a print head arranged in a plurality of rows on a print head has a line head that can eject ink of the same color and density.
When one pixel is composed of a dot pattern of n rows × n columns (n is a natural number of 2 or more) and one pixel is expressed with a resolution of 1 / n of the nozzle pitch,
In a pixel range given by k rows × k columns (k is a natural number of 2 or more), the number of dots constituting the pixel range is equal or almost equal to a line head of m columns (m is a natural number of 2 or more). A program for executing a process for determining the number of dots to be assigned to each line head so as to be assigned to each line head. A computer that functions as a print control device that controls a print head arranged in a plurality of rows on a print head has a line head that can eject ink of the same color and density.
When one pixel is composed of a dot pattern of n rows × n columns (n is a natural number of 2 or more) and one pixel is expressed with a resolution of 1 / n of the nozzle pitch,
In a pixel range given by k rows × k columns (k is a natural number of 2 or more), the number of dots constituting the pixel range is equal or almost equal to a line head of m columns (m is a natural number of 2 or more). A program for executing a process for determining the number of dots to be assigned to each line head so as to be assigned to each line head. In the case where a plurality of line heads capable of ejecting ink of the same color and density are arranged on the print head, one pixel has a dot pattern of n rows × n columns (n is a natural number of 2 or more). And a dot pattern data structure used when expressing one pixel at a resolution of 1 / n of the nozzle pitch,
The number of dots assigned to each line head is associated with each other so that the number of dots constituting one pixel is equally or almost evenly assigned to line heads of m columns (m is a natural number of 2 or more). The data structure of the dot pattern. In the case where a plurality of line heads capable of ejecting ink of the same color and density are arranged on the print head, one pixel has a dot pattern of n rows × n columns (n is a natural number of 2 or more). And a dot pattern data structure used when expressing one pixel at a resolution of 1 / n of the nozzle pitch,
In a pixel range given by k rows × k columns (k is a natural number of 2 or more), the number of dots constituting the pixel range is equal or almost equal to a line head of m columns (m is a natural number of 2 or more). The dot pattern data structure is characterized in that the number of dots assigned to each line head is associated with each other so that it can be assigned to each line head.

Images