JP3264574B2 - Color image recording method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a color image recording method for expressing a halftone by changing the length of an ink dot in the sub-scanning direction.

[0002]

2. Related Background Art As a color image recording method, a color thermal recording method, a color ink jet recording method, a color electrophotographic recording method and the like are known. In recent years, attention has been paid to a color thermal recording method due to miniaturization of the apparatus and simplicity of maintenance. The color thermal recording method includes color thermal recording in which a color image is directly recorded on a thermal recording sheet, and color thermal transfer recording in which the ink of an ink film is transferred to recording paper. The color thermal transfer recording includes a fusion type in which the molten ink is transferred to recording paper, and a sublimation type in which the amount of ink transferred to the recording paper changes according to thermal energy.

A color image recording method has been proposed which uses a recording head having a plurality of recording elements arranged in the main scanning direction and expresses gradation by changing the length of ink dots in the sub-scanning direction to square pixels. (For example, Japanese Patent Application No. 2-15)
886). This color image recording method has the following problems. That is, since the ink dots are lines extending in the main scanning direction, color moiré is likely to occur. Further, the pixel size is extremely small (for example, 125 × 12
5 .mu.m), and recording is performed while moving the recording paper in the sub-scanning direction. Therefore, pixels of each color do not match in the sub-scanning direction, and are often slightly shifted. When a displacement (registration displacement) of the position where the pixel is recorded occurs, the color tone of the color image changes and the color becomes different from that of the original image, or color unevenness occurs.

In order to eliminate the color moiré and the change in the color tone caused by the misregistration, the applicant of the present invention uses yellow, cyan,
Pixels of two colors of magenta have twice the length of the remaining one color pixel in the sub-scanning direction, and each color has a length of pixels in the sub-scanning direction between adjacent pixels in the main scanning direction. Has been proposed (for example, Japanese Patent Application No. 3-320521). However, this color image recording method has a problem in that gray scale of one of the three colors is sacrificed, and gray balance cannot be properly achieved.

[0005] On the other hand, the applicant of the present invention has proposed that, with respect to one color pixel among the three colors of yellow, cyan and magenta, the pixel is shifted by a predetermined pitch in the sub-scanning direction every other pixel in the main scanning direction. The image quality is degraded by shifting the pixels of the other two colors into groups of two pixels in the main scanning direction and shifting the pixels of this one group by a predetermined pitch in the sub-scanning direction every other group. A recording method for preventing a change in hue due to misregistration without registration has been proposed (for example, Japanese Patent Application No. 5-2906).

[0006]

However, in the above-described color image recording method, two of the three colors, yellow, cyan, and magenta, are recorded in the same pattern. The color ink is recorded over the previous ink. The higher the degree of overlap, the more muddy the color. This color turbidity is not a problem in a portion where the image density is high, but becomes a factor that deteriorates color reproducibility in a portion where the image density is low such as a highlight portion.
Also, the ink for thermal transfer is designed so that the ink is applied best when it is transferred onto the recording paper, and when the ink is transferred over the ink, it is directly transferred onto the recording paper. Ink gets worse than when it does. In particular, in a part where the image density is low, since the power supply time to the recording head is shortened, the ink to be transferred later is not recorded according to the data, and there is a disadvantage that the gradation of the part is deteriorated.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and provides a color image with vivid color reproducibility and gradation characteristics faithful to image data even in a low image density portion such as a highlight portion. It is an object of the present invention to provide a color image recording method capable of recording an image.

[0008]

In order to achieve the above-mentioned object, the invention described in claim 1 is directed to yellow, magenta,
Of the three cyan colors, one pixel is shifted in the sub-scanning direction by a predetermined pitch every other pixel in the main scanning direction for one color pixel, and the main scanning direction is shifted for the other two color pixels. Grouped every two pixels in the direction, so that each dot has a different dot pattern for each color.
The pixels of the group are shifted by a predetermined pitch in the sub-scanning direction.

According to a second aspect of the present invention, pixels of two colors out of three colors of yellow, magenta and cyan are
At every other pixel in the main scanning direction, the pixels are shifted in the sub-scanning direction by a predetermined pitch so that each color has a different dot pattern. The pixels are grouped, and every other group, the pixels of this one group are shifted in the sub-scanning direction by a predetermined pitch.

According to a third aspect of the present invention, in the color image recording method according to the first or second aspect, the pixel shift amount in the sub-scanning direction is の of the length of the pixel in the sub-scanning direction. Things. According to a fourth aspect of the present invention, in the color image recording method according to the second aspect, two colors for shifting a pixel every other pixel are magenta and cyan.

According to a fifth aspect of the present invention, a pixel of one of three colors of yellow, magenta and cyan is
For pixels that are odd-numbered in the main scanning direction, a dot pattern that increases the number of ink dots from one end to the other end is used, and for pixels that are even-numbered, ink dots are shifted from a predetermined start position of the pixel in the sub-scanning direction toward one end. After reaching one end, a dot pattern that increases the number of ink dots from the other end toward the start position is used. For the other two color pixels,
In the main scanning direction, the pixels are grouped by two pixels, and for each of these groups, one of the two colors is provided with an ink dot from one end to the other end to pixels of an odd-numbered group in the main scanning direction. Using an increased dot pattern, the number of ink dots is increased from the predetermined start position in the sub-scanning direction of the pixels to one end of the pixels in the even-numbered group, and after reaching one end, the ink dots are increased from the other end toward the start position. Using a dot pattern to increase the number of dots, one of the two colors
In color, pixels in odd-numbered groups in the main scanning direction
Pixels of even-numbered groups are formed using a dot pattern in which the number of ink dots is increased from a predetermined start position in the sub-scanning direction to one end of the pixel, and after reaching one end, the number of ink dots is increased from the other end toward the start position. In addition, a dot pattern is used in which ink dots are increased from one end to the other end.

According to a sixth aspect of the present invention, pixels of two colors out of three colors of yellow, magenta and cyan are
The dot pattern is divided into odd-numbered pixels and even-numbered pixels in the main scanning direction. In one of the two colors, a dot pattern in which the odd-numbered pixels increase the number of ink dots from one end to the other end A dot pattern that increases the number of ink dots from the predetermined start position in the sub-scanning direction of the pixel toward one end to even-numbered pixels, and after reaching one end, increases the number of ink dots from the other end toward the start position. In the other one color, the number of ink dots is increased from the predetermined start position of the pixel in the sub-scanning direction toward one end in the odd-numbered pixel,
After reaching one end, a dot pattern that increases the number of ink dots from the other end toward the start position is used, and a dot pattern that increases the number of ink dots from one end to the other end is used for even-numbered pixels. Pixels are grouped every two pixels in the main scanning direction, and for each of these groups, a pixel pattern of an odd-numbered group in the main scanning direction has a dot pattern that increases ink dots from one end to the other end. A dot pattern that increases the number of ink dots from a predetermined start position in the sub-scanning direction of the pixel toward one end in the pixels of the even-numbered group, and increases the ink dots from the other end toward the start position after reaching one end. Is used.

According to a seventh aspect of the present invention, in the color image recording method according to the fifth or sixth aspect, the start position of the pixel in the sub-scanning direction is set to の of the length of the pixel in the sub-scanning direction. Things. According to an eighth aspect of the present invention, in the color image recording method according to the sixth aspect, the two colors for changing the starting position for increasing the number of ink dots for every other pixel are magenta and cyan.

[0014]

When printing magenta, a dot pattern is used in which every other pixel in the main scanning direction is shifted by a predetermined pitch in the sub-scanning direction. In the recording of cyan and yellow, it is grouped every two pixels in the main scanning direction,
In the case of cyan, pixels of odd-numbered groups are recorded with a delay of ピ ッ チ pitch, and in the case of yellow, pixels of even-numbered groups are recorded with a delay of ピ ッ チ pitch. As described above, since each color is recorded in a different dot pattern, the overlap between inks is reduced in a portion where the image density is low, and the color reproducibility and gradation of the highlight portion are improved.

[0015]

FIG. 1 shows a recording state of a fusion type thermal transfer recording. As shown in FIG.
Has a plurality of heating elements 10a, 10b, 10c,... Arranged in a line in the main scanning direction (M). Each heating element
The length in the main scanning direction is L, and the length in the sub-scanning direction (S) is D. The length L in the main scanning direction is, for example, 125 μm, and the length D in the sub-scanning direction is, for example, 25 μm.

As shown in FIG. 2, the head driving section 11
The image data is converted into print data under the control of the controller 12, and the thermal head 10 is driven. The thermal head 10 has a heating element array having a platen drum 13.
Are arranged so as to extend in the axial direction. A recording paper 14 is mounted on the outer periphery of the platen drum 13.
It rotates in the sub-scanning direction indicated by the arrow at a constant pitch. An ink film 15 is disposed between the recording paper 14 and the thermal head 10, and guide rollers 16, 1 are provided.
7 while moving in the sub-scanning direction together with the recording paper 14. As is well known, cyan, magenta, and yellow ink areas are formed on the ink film 15 at a constant pitch.

As shown in FIG. 1B, a magenta pixel 18 surrounded by a dotted line has a rectangular shape with L on one side and F on the other side. The length L in the main scanning direction corresponds to the length of the heating element in the main scanning direction, and the length F in the sub-scanning direction is determined by the energized state of the heating element. In this embodiment, one pixel has ten gradations, and one pixel is composed of ten sublines. For example, in the case of one gradation, one sub-line is recorded, and in the case of two gradations, two sub-lines are recorded. Pixels adjacent in the main scanning direction have a recording position of F / 2 in the sub-scanning direction so that moire and parallel lines do not occur.
It is only shifted. In each pixel 15 shown in FIG. 1B, an ink dot 19 having an area ratio of 50% is recorded as indicated by hatching.

FIGS. 1C and 1D show cyan and yellow pixels, respectively. Similarly to the magenta pixel 18, the cyan pixel 20 and the yellow pixel 21 have a length L in the main scanning direction and a length F in the sub-scanning direction.
Is determined by the energized state of the heating element. Pixels adjacent in the main scanning direction are grouped every two pixels, and the recording position is shifted by F / 2 in the sub-scanning direction for each of these groups. Reference numerals 22 and 23 represent a cyan ink dot and a yellow ink dot having an area ratio of 50%. Note that the shift amount is not limited to F / 2.

FIG. 1E shows a state in which gray with an area ratio of 50% is recorded, which is shown in FIG.
Pixels of each color shown in (C) and (D) are superimposed.
As described above, in areas where the area ratio is equal to or less than 50%, cyan and yellow are not recorded in an overlapping manner. Therefore, areas with low image density, such as highlights, are recorded in a vivid color tone. Further, in a portion where the image density is low, half of each group of cyan and yellow is directly recorded on the recording paper 14, so that the ink transfer efficiency is improved and recording is performed with a gradation faithful to the image data.

In FIG. 3 showing the configuration of the head drive unit 11, each of the blue, green, and red image data input from a video tape recorder or a scanner is written into separate frame memories 25, 26, and 27, respectively. At the time of recording, the controller 12 reads out the image data representing the gradation level from each of the frame memories 25, 26, 27 line by line. At the time of this reading, in the case of green image data, the controller 12 operates the selector 28 to sort out the odd-numbered pixels and the even-numbered pixels in the main scanning direction. Then, the image data of the odd-numbered pixels is sent to the line memory 31, and the image data of the even-numbered pixels is sent to the line memory 32.

In the case of red and blue image data, the controller 12 operates the selector 28 to sort pixels in odd-numbered groups and pixels in even-numbered groups in the main scanning direction. In the case of red image data, the image data of the odd-numbered group of pixels is sent to the line memory 32, and the image data of the even-numbered group of pixels is sent to the line memory 31. In the case of blue image data, the image data of the odd-numbered group of pixels is sent to the line memory 31, and the image data of the even-numbered group of pixels is sent to the line memory 32.

The blue, green, and red image data written in the line memories 31 and 32 are transferred to buffer memories 33 and 34, respectively, and then stored in lookup table memories (hereinafter referred to as LUTs) 35 and 36, respectively. , Magenta, and cyan print data. The print data converted by the LUT 36 is delayed by a half pitch in the delay circuit 37.

The print data of the pixels in the first row is sequentially taken out for each sub-line to form a serial signal, which is sent to shift registers 38 and 39. The shift registers 38 and 39 convert a serial signal into a parallel signal and send it to the switching circuits 41 and 42.
The heating element array 44 includes a number of heating elements 10a and 10a.
, which are arranged in a line in the main scanning direction. The switching circuit 41 controls energization of odd-numbered heating elements in the heating element array 44, and the switching circuit 42 controls energization of even-numbered heating elements.

During recording, the platen drum 13 rotates in the sub-scanning direction indicated by an arrow while holding the recording paper 14. At the same time, the ink film 15 is fed in the direction of the arrow, and the start end of the magenta ink area is set below the thermal head 10. The green image data is read out from the frame memory 26 line by line, divided into odd-numbered pixels and even-numbered pixels in the main scanning direction, and converted into magenta print data. The print data of the pixel to be transmitted to the thermal head 10 is delayed by １ ／ pitch.

The thermal head 10 is driven in accordance with the printing data, and heats and presses the ink film 15 from behind to transfer the melted ink to the recording paper 14. Thus, as shown in FIG. 1B, the length in the sub-scanning direction changes according to the recording density, and the ink dots in a zigzag shape in the main scanning direction are recorded in the pixels 18. As the platen drum 13 rotates, a magenta image is recorded on the recording paper 14 line by line.

When the platen drum 13 makes one rotation, the starting end of the recording paper 12 returns to the recording start position, and the cyan film area of the ink film 15 is set. The red image data is divided into an odd-numbered group and an even-numbered group by the selector 28, and then the LU
At T35 and T36, the data is converted into cyan print data. The print data of the odd-numbered group is delayed by ピ ッ チ pitch, and the print data of the even-numbered group is sent to the thermal head 10 as it is, as shown in FIG.
A cyan image is recorded line by line.

In recording a yellow image, a yellow ink area is set on the thermal head 10 and
After the blue image data is divided into odd-numbered groups and even-numbered groups, it is converted into yellow print data by the LUTs 35 and 36 line by line. The print data of the odd-numbered group remains unchanged, and the print data of the even-numbered group is delayed by だ け pitch and supplied to the thermal head 10, and as shown in FIG. The data is recorded on the recording paper 12 line by line.

Another embodiment shown in FIG. 4 uses the same bat pattern for magenta and yellow as in the previous embodiment, and for cyan, the odd-numbered pixels and the even-numbered pixels in the main scanning direction. And the print data of the odd-numbered pixels are delayed by ピ ッ チ pitch. As a result, magenta and cyan are not recorded in the low-density portion having an area ratio of 50% or less, and the highlight portion becomes vivid and the gradation is improved similarly to the above embodiment. In addition, when a grouped dot pattern is used, the dot pattern can be easily recognized by the naked eye depending on the design and may have a rough impression, but in this embodiment, the colors to be grouped have low density and are not conspicuous in the same area. Since there is only one type of yellow, the appearance impression is less.

Next, another embodiment will be described with reference to FIGS. 5, 6, and 7. FIG. For magenta, see Figure 5,
As shown in FIG. 6A, a dot pattern in which the number of ink dots increases from one end to the other end is used for an odd-numbered pixel in the main scanning direction, and the length of a pixel in the sub-scanning direction is increased for an even-numbered pixel. In this case, a dot pattern is used in which the number of ink dots is increased from a start position of 1/2 of F toward one end, and after reaching one end, the number of ink dots is increased from the other end toward the start position.

In addition, cyan and yellow are grouped for every two adjacent pixels in the main scanning direction, and for each of these groups, the ink between the pixels of the odd-numbered group and the pixels of the even-numbered group is set. The dot pattern is changed. That is, as shown in FIGS. 5B and 6B, in the pixels of the group of odd-numbered groups of cyan, as shown in FIGS. A dot pattern is used in which the number of ink dots is increased, and after reaching one end, the number of ink dots is increased from the other end toward the start position. In addition, as shown in FIGS. 5A and 6B, a dot pattern in which the number of ink dots is increased from one end to the other end is used for the pixels of the even-numbered group.

In the case of yellow, as shown in FIG. 6 (C), the pixels of the odd-numbered groups are the opposite of cyan, as shown in FIG. 5 (A), from one end to the other end. As shown in FIG. 5 (B), a dot pattern for increasing the number of ink dots is used. A dot pattern is used in which the number of dots is increased, and after reaching one end, the number of ink dots is increased from the other end toward the start position. The recording start position of the ink dot is located at the center of the pixel, that is, 1/1 / L of the length F of the pixel in the sub-scanning direction.
2, but also 1/1 of the length of the pixel in the sub-scanning direction.
3, 2/3, 3/4, 3/5, etc.

As shown in FIG. 6A, a magenta pixel 50 surrounded by a solid line has a rectangular shape with L on one side and F on the other side. The length L in the main scanning direction corresponds to the length of the heating element in the main scanning direction, and the length F in the sub-scanning direction is determined by the energized state of the heating element. In this embodiment, since one pixel has ten gradations, one pixel is composed of ten sublines SL1 to SL10. For example, in the case of one gradation, the sub-line of SL1 is recorded, and in the case of two gradations, the sub-lines of SL1 and SL2 are recorded. FIG.
In each pixel 50 shown in (A), an ink dot 51 having an area ratio of 50% is recorded as shown by hatching.

FIGS. 6B and 6C show cyan and yellow pixels, respectively. Like the magenta pixel 50, the cyan pixel 52 and the yellow pixel 53 also have a length L in the main scanning direction and a length F in the sub-scanning direction.
Is determined by the energized state of the heating element. Note that reference numeral 5
4 and 55 represent cyan ink dots and yellow ink dots. When these pixels are superimposed, the pattern shown in FIG. 1E is obtained in the same manner as in the first embodiment. That is, the color tone and gradation of a portion having a low image density such as a highlight portion are reproduced well.

FIG. 7 shows a head driving section 56 for recording a pixel pattern as shown in this embodiment. The difference from the head drive unit 11 of the first embodiment shown in FIG. 3 is that the delay circuit 37 is omitted and the LUT 57
Generates print data for recording the dot pattern shown in FIG. 5A according to the image data, and the LUT 58 generates print data of the dot pattern shown in FIG. 5B according to the image data. is there.

Thus, at the gradation level "0", no ink dot is recorded, and at the gradation level "1", an ink dot composed of the SL1 sub-line is recorded. Similarly, in the case of gradation "8", ink dots composed of sub-lines SL1 to SL8 are recorded. In this way 1
When the recording of the pixels is completed, the pixels are recorded line by line in the same procedure. After the recording of one color is completed, the other two colors are recorded in the same procedure. In this case, as described above, grouping is performed every two pixels in the main scanning direction.
The pattern used for the odd-numbered group and the even-numbered group is changed.

In each of the above embodiments, a line printer has been described as an example. However, the present invention can be applied to a serial printer which moves relative to two dimensions. Although each of the above embodiments is a fusion type thermal transfer recording, the present invention can be applied to a sublimation type thermal transfer recording, a thermal recording, an ink jet recording, an electrophotographic recording and the like.

[0037]

As described above, according to the color image recording method of the present invention, since each color is recorded in a different dot pattern, the overlap between inks is reduced in a portion where the image density is low. The color turbidity is eliminated, and the highlight portion can be recorded vividly. Further, in the highlight portion, since the area directly recorded on the recording paper is increased and the ink is applied well, good gradation can be obtained.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a recording state when each pixel of yellow, magenta, and cyan and gray in which these are superimposed have an area ratio of 50%.

FIG. 2 is a schematic view showing a fusion-type thermal transfer recording apparatus embodying the present invention.

FIG. 3 is a block diagram of a head driving unit.

FIG. 4 is an explanatory diagram showing a printing state when yellow, magenta, and cyan pixels and gray in which these are superimposed and the area ratio of which is 50% are printed in another embodiment.

5A is an explanatory diagram showing a dot pattern of an odd-numbered pixel, and FIG. 5B is an explanatory diagram showing a dot pattern of an even-numbered pixel.

FIG. 6 is an explanatory diagram showing a recording state of each pixel of yellow, magenta, and cyan.

FIG. 7 is a block diagram of a head drive unit according to an embodiment using the dot patterns shown in FIGS. 5 and 6;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Thermal head 10a, 10b ... Heating element 11 Head drive part 14 Recording paper 15 Ink film 18, 20, 21, 50, 52, 53 Pixel 19, 22, 23, 51, 54, 55 Ink dot 37 Delay circuit

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B41J 2/325 B41J 2/355 B41J 2/525

Claims (8)

(57) [Claims] 1. A printing head in which a plurality of printing elements are arranged in a main scanning direction, the length of an ink dot printed in a pixel in the sub-scanning direction is changed in accordance with the density, and at least yellow, magenta, In a color image recording method for recording a color image on recording paper by using three kinds of ink dots of cyan, one pixel among the three colors of yellow, magenta, and cyan is disposed every other pixel in the main scanning direction. In addition, the pixels are shifted in the sub-scanning direction by a predetermined pitch, and the other two-color pixels are grouped every two pixels in the main-scanning direction so that a different dot pattern is obtained for each color.
A color image recording method characterized by shifting the pixels of this one group in the sub-scanning direction by a predetermined pitch every other group. 2. Using a recording head in which a plurality of recording elements are arranged in a main scanning direction, the length of an ink dot recorded in a pixel in the sub scanning direction is changed according to the density, and at least yellow, magenta, In a color image recording method for recording a color image on recording paper using three kinds of ink dots of cyan, two pixels among the three colors of yellow, magenta, and cyan are alternately arranged in the main scanning direction. In addition, the pixels are shifted in the sub-scanning direction by a predetermined pitch so that each color has a different dot pattern, and the other one-color pixels are grouped every two pixels in the main scanning direction.
A color image recording method characterized by shifting the pixels of this one group in the sub-scanning direction by a predetermined pitch every other group. 3. The color image recording method according to claim 1, wherein the amount of pixel shift in the sub-scanning direction is の of the length of the pixel in the sub-scanning direction. Recording method. 4. The color image recording method according to claim 2, wherein the two colors whose pixels are shifted every other pixel are magenta and cyan. 5. Using a recording head in which a plurality of recording pixels are arranged in a main scanning direction, the length of ink dots recorded in the pixels in the sub-scanning direction is changed according to the density, and at least yellow, magenta, In a color image recording method for recording a color image on recording paper using three kinds of ink dots of cyan, among the three colors of yellow, magenta, and cyan, pixels of one color are odd-numbered in the main scanning direction. Pixel
A dot pattern that increases the number of ink dots from one end to the other end is used. For even-numbered pixels, the number of ink dots increases from a predetermined start position in the sub-scanning direction of the pixel to one end, and after reaching one end, the other end And a dot pattern that increases the number of ink dots from the starting position to the starting position. Pixels of the other two colors are grouped every two pixels in the main scanning direction, and for each of these groups, one of the two colors, 1 In the color, a dot pattern that increases the number of ink dots from one end to the other end is used for pixels in an odd-numbered group in the main scanning direction, and a predetermined start in the sub-scanning direction of pixels is used for pixels in an even-numbered group. A dot pattern is used in which the number of ink dots is increased from the position toward one end, and after reaching one end, the number of ink dots is increased from the other end toward the start position.
In the other one of the colors, the number of ink dots is increased from a predetermined start position in the sub-scanning direction of the pixel toward one end of the pixel of the group that is an odd number in the main scanning direction, and the other end is reached after reaching one end. A dot pattern that increases the number of ink dots from the first to the starting position, and uses a dot pattern that increases the number of the ink dots from one end to the other end for the pixels of the even-numbered group. 6. A printing head in which a plurality of printing pixels are arranged in a main scanning direction, the length of ink dots printed in the pixels in the sub-scanning direction is changed according to the density, and at least yellow, magenta, In a color image recording method for recording a color image on recording paper using three types of cyan ink dots, two of the three colors yellow, magenta, and cyan are odd-numbered in the main scanning direction. Pixel and even-numbered pixels. Of these two colors, one of the two colors is an even-numbered pixel using a dot pattern that increases the number of ink dots from one end to the other. Increase the number of ink dots in the pixel from a predetermined start position in the sub-scanning direction of the pixel toward one end, and after reaching one end, increase the ink dots from the other end toward the start position In the other one color, the number of ink dots is increased from the predetermined start position in the sub-scanning direction of the pixel to one end in the other one color, and after reaching one end, the ink dot is moved from the other end to the start position. Using a dot pattern that increases the number of ink dots,
A dot pattern for increasing the number of ink dots from one end to the other end is used for even-numbered pixels, and the remaining one-color pixels are grouped every two pixels in the main scanning direction. Pixels in the odd-numbered group in the main scanning direction use a dot pattern that increases the number of ink dots from one end to the other end. Pixels in the even-numbered group use one pixel from a predetermined start position in the sub-scanning direction. A color image recording method using a dot pattern in which the number of ink dots increases toward one end, and after reaching one end, increases from the other end toward the start position. 7. A color image recording method according to claim 5, wherein the start position of the pixel in the sub-scanning direction is set to １ ／ of the length of the pixel in the sub-scanning direction. Recording method. 8. The color image recording method according to claim 6, wherein the two colors for changing the starting position for increasing the number of ink dots for every other pixel are magenta and cyan.