JPH1110916A - Method and apparatus for gradational recording - Google Patents

Abstract

PROBLEM TO BE SOLVED: To record high-quality images of superior gradational feature by thinning image data corresponding to each of a plurality of inks of different densities so that at least two ink dots of one pair having densities different by one level do not overlap. SOLUTION: An allotment table 32 allots input image data from a lowest density '255' to a predetermined intermediate density, e.g. '127' for output image data of a D1 ink. When the input image data are between the intermediate density and a highest density '0', the allotment table sets the output image data to '0'. The allotment tale allots input image data from '255' to '0' for output image data of a D2 ink, and further input image data from the intermediate density to '0' for output image data of a D3 ink. The generated output image data for D1, D2, D3 inks are thinned with the use of matrix circuits 32A, 32B, 32C and black areas of matrices are rendered record areas.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gradation recording method and a gradation recording apparatus for performing gradation recording using at least two kinds of inks having different densities.

[0002]

2. Description of the Related Art Conventionally, as a recording method in a facsimile machine, a digital copying machine, a digital printer, and the like,
Examples include an electrophotographic system, a sublimation transfer system, a thermal transfer system, and an ink jet recording system. As a method of recording a gradation image by these methods, by changing the voltage or pulse width applied to the recording head,
A method of modulating the recording dot diameter or recording dot density of toner, ink, dye, etc. attached to a recording medium,
A method is known in which the recording dot diameter or the recording dot density is constant and the number of dots recorded in a unit matrix is modulated. Further, a gradation recording method using a combination of the above-described dot diameter or density modulation method and dot modulation method is also known.

[0003] In the gradation recording by these modulation methods,
Due to the limitations imposed by the output device as an image recording device, it is difficult to perform modulation in accordance with the gradation value of the recording dot diameter, or when the recording dot density (resolution) is low, the size of the input image must be increased unless the unit matrix is increased. The key could not be reproduced on the recording medium. Therefore, an error diffusion method, an average density approximation method, or the like, which expresses a pseudo tone in image processing, has been proposed.

The error diffusion method binarizes multi-valued image data of a target pixel of an input image, weights an error between a binarization level and multi-valued image data before binarization, and weights an error in the vicinity of the target pixel. Is added to the image data. As described in Japanese Patent Application Laid-Open No. 57-104396, the average density approximation method uses the already binarized binary data in the vicinity of the target pixel to obtain a black or white binary value for the target pixel. In this case, a weighted average value of each of the neighboring pixels is calculated, and the image data of the target pixel is binarized using the average of the two average values as a threshold value.

In recent years, a multi-valued error diffusion method using pseudo-halftone processing using inks of different densities has also attracted attention in recent years.

[0006] Further, as an ink jet recording method,
A method of performing gradation recording using inks having different densities when recording one pixel is also known. JP-A-5-20103
Japanese Patent Application Laid-open No. 2 (1999) -2000 discloses that, when printing is performed using inks having different densities using a plurality of print heads, a table determined according to the gradation value of the input image is used for each print head that ejects inks having different densities. On the other hand, proposals have been made to sort the images to be recorded by them.

[0007]

In the case of the above-described conventional gradation recording method, when the recording dot density (resolution) of the output device is high and the recording dot diameter can be sufficiently modulated, excellent gradation recording is performed. Recording is possible. However, when the recording dot density (resolution) of the output device is low or the modulation of the recording dot diameter is limited, pseudo halftone processing by image processing is required to perform excellent gradation recording.

On the other hand, the error diffusion method as a pseudo halftone recording method corrects an error between input image data and output image data, so that the density of an input image and an output image can be stored, and the resolution and It is possible to provide an image with excellent gradation. The average density approximation method is 2
Since the calculation is performed using the binary data after the binarization, the hardware configuration can be simplified, and the pseudo halftone processing of the image can be performed with a small processing amount, so that the processing can be sped up. However, images binarized by these pseudo halftone processing methods are output devices having a low output image resolution, for example, 2400 dpi or less, particularly 1200 dpi.
When recording is performed with an output device having a low resolution of about i or less, each of the pixels constituting the image is observed like noise,
It was difficult to represent a smooth gradation image.

A multi-valued error diffusion method that has been recently proposed includes dividing input data into a plurality of areas based on gradation values, binarizing the data using a plurality of thresholds, and setting each area to a set recording dot. The method of recording by diameter or recording dot density, the input data is divided into areas according to a predetermined table, and each is subjected to pseudo halftone processing,
There is a method of recording with a set recording dot diameter or recording dot density. However, in these methods, the so-called “gradation skip” in which the boundary of the reproduced tone of each divided area loses smoothness, that is, a so-called “jump of gradation” easily occurs, and the recording dot diameter or the recording dot It was difficult to set and manage the optimum concentration.

[0010] Further, as an ink jet recording method,
In the case of using a multi-nozzle head to scan the recording medium with the head and perform recording in a plurality of line units, unevenness in the feeding of the recording medium in each of a plurality of lines, unevenness in the accuracy of the multi-nozzle head, and the like cause a streak. There is a possibility that a so-called "joining streak" may occur as a recording defect, and although various measures have been taken to solve the problem, it has not yet been resolved.

An object of the present invention is to form a dot on a recording medium by using a plurality of inks having different densities, so that a high quality image with excellent gradation can be recorded. It is to provide a recording method and a gradation recording device.

[0012]

A gradation recording method according to the present invention is a gradation recording method for forming a dot on a recording medium with a plurality of inks having different densities and recording a gradation image by a set of the dots. The image data corresponding to each of the plurality of inks is thinned out, and the image data corresponding to at least one set of two inks having different densities by one step is thinned out so that the dots of the two inks do not overlap. Forming a plurality of ink dots on the recording medium based on the image data obtained.

According to a gradation recording apparatus of the present invention, in a gradation recording apparatus for forming a dot on a recording medium with a plurality of inks having different densities and recording a gradation image by a group of the dots, Thinning means for thinning out corresponding image data, and thinning out image data corresponding to at least one set of two inks whose density differs by one step so that dots of the two inks do not overlap;
Control means for forming the plurality of ink dots on the recording medium based on the thinned image data.

According to the present invention, when thinning out image data corresponding to each of a plurality of inks having different densities, the dots of at least one set of two inks having different densities by one step are thinned out so as not to overlap. For example, low density ink dots are formed in the lowest density recording area, and low density ink dots and one step higher medium density ink dots are formed in the higher density recording area. In a print area having a high density, dots of medium-density ink and dots of high-density ink one step higher are formed. As a result, in particular, during image recording based on binarized image data, isolated dots of high-density ink are generated as compared with the case where isolated dots of high-density ink are formed directly on the ground color of the recording medium. It is difficult to eliminate the graininess caused by isolated dots.

[0015]

Embodiments of the present invention will be described below in detail with reference to the drawings.

(First Embodiment) FIG. 1 shows a first embodiment of the present invention.
1 shows a configuration of a main part of an ink jet printer as an embodiment of the present invention. On a carriage 1 in FIG. 1, four multi-nozzle heads (recording heads) 2 are provided. Each multi-nozzle head 2 has 64 nozzles forming 64 ink ejection ports. In this example, as described later, recording is performed using three of the four heads 2. The inks ejected from each of the three heads 2 are of the same color, and the first density D1, the second density D2 ink, and the third density D3 ink. To each of the heads 2, a D1 ink having a first density, an S2 ink having a second density, and a D3 ink having a third density are supplied from ink tanks 3 provided correspondingly. Drive signals are supplied to these multi-nozzle heads 2 via a flexible insulating belt 4 having a large number of conductive wires. The carriage 1 having such a configuration is guided by a guide rail 5 so as to be movable in the X1 and X2 directions in the figure, and further connected to a belt 6. The belt 6 is reciprocated in a main scanning direction indicated by arrows X1 and X2 by a pulse motor (not shown), and accordingly, the carriage 1 is forward-scanned in the arrow X1 direction or backward-scanned in the arrow X2 direction. Further, by feeding the recording medium 7 in the sub-scanning direction indicated by the arrow Y, an image is recorded on the recording medium 7 by each density ink ejected from the ejection port of each head 2.

FIG. 2 is a block diagram of an image processing section for generating recording image data from input image data in the above-described ink jet printer. In this example, the input image data is an 8-bit digital value, data corresponding to the highest density (dark) portion of the document is “0”, and data corresponding to the lowest density (bright) portion is “255”.
And Input image data is stored in the image memory 31, and the sorting table 32 sorts the input image data as shown in FIG. 3, and outputs the output image data for D1 ink, the output image data for D2 ink, and the D3 ink. Generate output image data. As the distribution table 32, a table that performs correction using an LUT (lookup table) in consideration of the measurement results of the recording densities of the inks D1, D2, and D3 on the recording medium 7 in advance may be used.

The sorting table 32 of the present embodiment sorts the input image data from "255" to predetermined intermediate data (for example, "127") with respect to the output image data for D1 ink. From "0" to "0", the input image data from "255" to "0" is sorted for the output image data for D2 ink, and the output image data for D3 ink is The input image data from the intermediate data to “0” is sorted.

The generated output image data for D1, D2, and D3 inks is stored in a matrix circuit 32A, as shown in FIG.
Thinning-out (hereinafter referred to as "matrixing") is performed using a matrix of 32B and 32C. In the matrix of FIG. 4, the black cell area is a recording area, and the blank area is an area where dots are not formed. In the matrixing, as shown in FIG. 5A, a pixel matrixed with respect to the target pixel M (i, j) is defined as K (i, j).

The matrix of the output image data for the D1 ink is as follows: Since the D1 ink recording area matrix covers the entire surface as shown in FIG. 4, K (i, j) = M (i, j) (i, j is (Natural number).

The output image data for D2 ink is matrixed because the D2 ink recording area matrix is in a staggered pattern as shown in FIG.

[0022]

K (i, j) = 0 K (i + 1, j) = (M (i, j) + M (i + 1, j)
/ 2 K (i, j + 1) = (M (i, j + 1) + M (i, +
1, j + 1)) / 2 K (i + 1, j + 1) = 0.

Further, the output image data for D3 ink is formed into a matrix because the D3 ink recording area matrix is in a zigzag lattice shape opposite to the D2 ink recording area matrix as shown in FIG.

[0024]

## EQU2 ## K (i, j) = (M (i, j) + M (i + 1,
j)) / 2 K (i + 1, j) = 0 K (i, J + 1) = 0 K (i + 1, j + 1) = (M (i, j + 1) + M (i +
1, j + 1)) / 2.

With such a matrix, the resolution of the input image data is reduced by half in the main scanning direction and the sub-scanning direction. When the resolution is maintained, if the resolution of the output device can cope with the resolution, as shown in FIG.
(I, j) may be divided into four to generate output image data for D1, D2, and D3 inks. At that time, M (i,
It is preferable to apply various corrections to the data of the pixels divided into four parts according to the adjacent pixels in j).

As described above, distribution is performed by the distribution table 32, and the matrix circuits 32A, 32B, 3
The image data matrixed by 2C is 2 in FIG.
Organized dither method in the binarization circuits 33A, 33B, 33C,
Pseudo halftone processing is performed by an error diffusion method, an average density storage method, or the like. In the case of this example, an error diffusion method using a general FLOYD / STEINBERG (reference R. FLOYD & L. STEINBERG, “AN A
DAPTIVE ALGORITHMFORSPECIAL GRAY SCALE ”, SID 75
DIGEST, PP36 to 37), the error was distributed to the recording area shown in FIG.

On the basis of the binarized output image data for D1, D2, and D3 inks, a desired image is recorded on the recording medium by main scanning of the carriage 1 of the ink jet printer shown in FIG. 7 was recorded. As a result, an image having a smooth gradation characteristic in which noise and graininess were not noticeable was recorded. That is, since the black square area in FIG. 3 is used as the recording area, the amount of ink that is overprinted on one pixel in the recording of the same color on the recording medium 7 is a maximum of two dots. A dot of D3 ink is formed, a dot of D2 ink is formed around the pixel, and a dot of D1 ink is further formed.
The overprinting effect of the ink dot and the D2 ink dot and the overprinting effect of the D1 ink dot and the D3 ink dot make the isolated dots of the D2 and D3 inks inconspicuous.

Further, with respect to ink dots having different densities by one step, since their recording area matrices are different, it is difficult for dots to overlap on the recording medium 7. For this reason, in particular, as in the case of ink jet recording, a problem that occurs when ink is repeatedly applied to the same place on the recording medium 7, that is, the recording medium 7 does not absorb the ink completely and bleeds, or the recording medium 7 undulates or wrinkles. Also, it is possible to avoid the troubles that occur.

Further, since the recording areas are set in a matrix for each ink of each density, a so-called "connecting streak" which is particularly likely to occur in a jet recording method using a multi-nozzle head having a plurality of ink ejection ports can be eliminated. Also.

(Second Embodiment) Four heads 2 of the printer shown in FIG. 1 are used, and D1, D2,
D3 and D4 inks are ejected. These inks are similar in color and have a first density D1 ink, a second density D2 ink, a third density D3 ink, a fourth density D4 ink, and Become. The recording area matrix for those inks was set as shown in FIG. 6, and the distribution table 32 was set as shown in FIG. 7, and recording was performed in the same manner as in the first embodiment. The matrices for the D1 and D2 inks cover the entire surface, and the matrices for the D3 and D4 inks are in the form of a zigzag lattice having a shape opposite to each other. Also in this embodiment, noise,
An image having a smooth gradation without inconspicuous granularity was recorded.

(Third Embodiment) Four heads 2 of the printer shown in FIG. 1 are used, and D1, D2,
D3 and D4 inks are ejected. These inks are similar in color and have a first density D1 ink, a second density D2 ink, a third density D3 ink, a fourth density D4 ink, and Become. The recording area matrix for these inks was set as shown in FIG. 8, and the distribution table was set as shown in FIG. 9, and printing was performed in the same manner as in the first embodiment. Also in the present embodiment, an image having a smooth gradation characteristic with no noticeable noise and graininess was recorded.

In the embodiment of the present invention described above, dots are formed by ejecting liquid ink and landing it on the recording medium 7, but the ink is an ink that solidifies at room temperature or below. There may be used one that softens or liquefies at room temperature.

The present invention is not limited to ink jet recording, but can be applied to recording systems such as a thermal transfer recording system and an electrophotographic system. Furthermore, it is also possible to control the diameter and the number of dots by multi-valued image data.

When recording a print or the like, the result of matrix-recording is fed back according to the density of dots printed on a recording medium in a test manner, and the LUT is corrected by adding a LUT correction. It is preferable to control the value.

Further, in the above-described embodiment, printing is performed using a plurality of dark and light inks of the same color. However, it is also possible to print a multicolor gradation image using the dark and light inks of each of the plurality of colors. is there. For example, cyan, magenta,
A similar process can be applied to each of yellow and black for recording, and a full-color output image can be recorded.

Further, by forming the input image data into a matrix corresponding to each ink without using the distribution table 32, it is possible to generate output image data for each ink similar to the above-described embodiment. It is possible.

(Others) It should be noted that the present invention includes a means (for example, an electrothermal converter or a laser beam) for generating thermal energy as energy used for performing ink ejection, particularly in an ink jet recording system. An excellent effect is obtained in a recording head and a recording apparatus of a type in which the state of ink is changed by the thermal energy. This is because according to such a method, it is possible to achieve higher density and higher definition of recording.

The typical configuration and principle are described in, for example, US Pat. Nos. 4,723,129 and 4,740.
It is preferable to use the basic principle disclosed in the specification of Japanese Patent No. 796. This method is a so-called on-demand type,
Although it can be applied to any type of continuous type, in particular, in the case of the on-demand type, it can be applied to a sheet holding liquid (ink) or an electrothermal converter arranged corresponding to the liquid path. By applying at least one drive signal corresponding to the recorded information and giving a rapid temperature rise exceeding the nucleate boiling, heat energy is generated in the electrothermal transducer, and film boiling occurs on the heat acting surface of the recording head. Liquid (ink) corresponding to this drive signal on a one-to-one basis.
This is effective because air bubbles inside can be formed. The liquid (ink) is ejected through the ejection opening by the growth and contraction of the bubble to form at least one droplet. When the drive signal is formed into a pulse shape, the growth and shrinkage of the bubble are performed immediately and appropriately, so that the ejection of a liquid (ink) having particularly excellent responsiveness can be achieved, which is more preferable. As the pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. Further, if the conditions described in US Pat. No. 4,313,124 relating to the temperature rise rate of the heat acting surface are adopted, more excellent recording can be performed.

As the configuration of the recording head, in addition to the combination configuration (a linear liquid flow path or a right-angled liquid flow path) of a discharge port, a liquid path, and an electrothermal converter as disclosed in the above-mentioned respective specifications. U.S. Pat. No. 4,558,333 and U.S. Pat. No. 44,558 which disclose a configuration in which a heat acting portion is arranged in a bending region.
A configuration using the specification of Japanese Patent No. 59600 is also included in the present invention. In addition, Japanese Unexamined Patent Application Publication No. 59-123670 discloses a configuration in which a common slit is used as a discharge portion of an electrothermal converter for a plurality of electrothermal converters, and an aperture for absorbing a pressure wave of thermal energy is provided. The effect of the present invention is effective even if the configuration is based on JP-A-59-138461, which discloses a configuration corresponding to a discharge unit. That is, according to the present invention, recording can be reliably and efficiently performed regardless of the form of the recording head.

Further, the present invention can be effectively applied to a full-line type recording head having a length corresponding to the maximum width of a recording medium on which a recording apparatus can record. Such a recording head may have a configuration that satisfies the length by a combination of a plurality of recording heads, or a configuration as one integrally formed recording head.

In addition, even in the case of the serial type as described above, the recording head fixed to the apparatus main body or the electric connection with the apparatus main body or the ink from the apparatus main body by being attached to the apparatus main body. The present invention is also effective when a replaceable chip-type recording head that can be supplied or a cartridge-type recording head in which an ink tank is provided integrally with the recording head itself is used.

It is preferable to add ejection recovery means for the recording head, preliminary auxiliary means, and the like as the configuration of the recording apparatus of the present invention since the effects of the present invention can be further stabilized. If these are specifically mentioned, the recording head is heated using capping means, cleaning means, pressurizing or suction means, an electrothermal transducer, another heating element or a combination thereof. Pre-heating means for performing the pre-heating and pre-discharging means for performing the discharging other than the recording can be used.

The type and number of recording heads to be mounted are not limited to those provided for only one color ink, for example, and for a plurality of inks having different recording colors and densities. A plurality may be provided. That is, for example, the printing mode of the printing apparatus is not limited to a printing mode of only a mainstream color such as black, but may be any of integrally forming a printing head or a combination of a plurality of printing heads. The present invention is also very effective for an apparatus provided with at least one of the recording modes of full color by color mixture.

In addition, in the embodiments of the present invention described above, the ink is described as a liquid. However, an ink which solidifies at room temperature or lower and which softens or liquefies at room temperature may be used. In general, the ink jet method generally controls the temperature of the ink itself within a range of 30 ° C. or more and 70 ° C. or less to control the temperature so that the viscosity of the ink is in a stable ejection range. Sometimes, the ink may be in a liquid state. In addition, in order to positively prevent temperature rise due to thermal energy by using it as energy for changing the state of the ink from a solid state to a liquid state, or to prevent evaporation of the ink, the ink is solidified in a standing state and heated. May be used. In any case, the application of heat energy causes the ink to be liquefied by the application of the heat energy according to the recording signal and the liquid ink to be ejected, or to start solidifying when it reaches the recording medium. The present invention is also applicable to a case where an ink having a property of liquefying for the first time is used. In such a case, the ink
JP-A-54-56847 or JP-A-60-7
As described in Japanese Patent Publication No. 1260, it is also possible to adopt a form in which the sheet is opposed to the electrothermal converter in a state where it is held as a liquid or solid substance in the concave portion or through hole of the porous sheet. In the present invention, the most effective one for each of the above-mentioned inks is to execute the above-mentioned film boiling method.

In addition, the form of the ink jet recording apparatus of the present invention is not only used as an image output terminal of an information processing apparatus such as a computer, but also for a copying apparatus combined with a reader or the like, and a facsimile apparatus having a transmission / reception function. It may take a form.

[0046]

As described above, according to the present invention,
When thinning out image data corresponding to a plurality of inks having different densities, thinning is performed so that dots of at least one set of two inks having different densities by one step do not overlap, thereby providing a high-quality image with excellent gradation characteristics. Can be recorded.

For example, the input image data is distributed for each ink, the image data for each ink is formed into a matrix by a recording area matrix in order to thin out the data, and the matrix is subjected to binarization by a pseudo halftone process or the like. By printing an image based on the data, a low-density ink dot is formed in a low-density recording area, and a low-density ink dot and a medium-density ink dot are formed in a medium-density recording area, In the high-density recording area, medium-density ink dots and high-density ink dots are formed to reduce the noise and graininess of the recorded image due to isolated dots, and to produce images with excellent gradation. Can be recorded.

Further, by forming a matrix in order to thin out the image data corresponding to each ink and reducing the overlap of the ink dots that land on each pixel, the ink on the recording medium, which has been regarded as a problem in the ink jet recording apparatus, is particularly useful. Overflow and distortion of the recording medium can be prevented.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view of a main part of an ink jet printer as a recording apparatus of the present invention.

FIG. 2 is a block diagram of an image processing unit in the recording apparatus of the present invention.

FIG. 3 is an explanatory diagram of a distribution table according to the first embodiment of the present invention.

FIG. 4 is an explanatory diagram of a recording area matrix according to the first embodiment of the present invention.

FIG. 5 is an explanatory diagram of matrix formation by a recording area matrix in the present invention.

FIG. 6 is an explanatory diagram of a recording area matrix according to a second embodiment of the present invention.

FIG. 7 is an explanatory diagram of a distribution table according to the second embodiment of the present invention.

FIG. 8 is an explanatory diagram of a recording area matrix according to a third embodiment of the present invention.

FIG. 9 is an explanatory diagram of a distribution table according to a third embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Carriage 2 Multi-nozzle head 3 Ink tank 4 Flexible insulating belt 5 Guide rail 6 Belt 7 Recording medium

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masataka Yashima 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc.

Claims (15)

[Claims] 1. A gradation recording method in which dots are formed on a recording medium with a plurality of inks having different densities and a gradation image is recorded by a set of the dots, wherein the image data corresponding to each of the plurality of inks is thinned out. In addition, with respect to image data corresponding to at least one set of two inks whose densities are different by one step, thinning is performed so that the dots of the two inks do not overlap. Based on the thinned image data, the dots of the plurality of inks are formed. A gradation recording method, wherein the gradation recording method is formed on the recording medium. 2. At least three inks having different densities are used as the inks. For image data corresponding to at least one set of two inks having two different densities, dots of the two inks are overlapped. 2. The gradation recording method according to claim 1, wherein the thinning is performed. 3. The gradation recording method according to claim 1, wherein the image data corresponding to the ink having the lowest density is not thinned out. 4. The gradation recording method according to claim 1, wherein the image data for each of the plurality of inks is thinned out in a staggered pattern. 5. The image processing apparatus according to claim 1, wherein input image data is distributed to the plurality of inks in accordance with a gradation, thereby generating image data for each of the plurality of inks. Gradation recording method. 6. The method according to claim 1, wherein the image data for each of the plurality of inks is thinned out, the gradation of the image data is binarized, and the dots are formed based on the binarized data. The gradation recording method according to any one of claims 1 to 5, wherein: 7. A gradation recording apparatus which forms dots on a recording medium with a plurality of inks having different densities and records a gradation image by a set of the dots, wherein the image data corresponding to each of the plurality of inks is thinned out. And for image data corresponding to at least one set of two inks having different densities by one step, a thinning-out unit for thinning out the dots of the two inks so as not to overlap, and the plurality of inks based on the thinned-out image data. And a control unit for forming dots on the recording medium. 8. The image forming apparatus according to claim 1, wherein the thinning means uses at least three inks having different densities as the ink, and the thinning means applies, for image data corresponding to at least one set of two inks having two different densities, the two inks. The gradation recording apparatus according to claim 7, wherein the dots are thinned out so as to overlap the dots. 9. The gradation recording apparatus according to claim 7, wherein said thinning-out means does not thin out image data corresponding to the ink having the lowest density. 10. The gradation recording apparatus according to claim 7, wherein said thinning-out means is a matrix for thinning out the image data for each of the plurality of inks in a staggered grid pattern. 11. A distribution unit for generating image data for each of the plurality of inks by distributing input image data to the plurality of inks in accordance with gradations. The gradation recording device according to any one of the above. 12. A processing unit for thinning out the image data for each of the plurality of inks and then performing a binarization process on the gradation of the image data, wherein the control unit performs processing based on the binarized data. The method according to claim 7, wherein the dots are formed.
2. The gradation recording device according to claim 1. 13. The printing apparatus according to claim 7, further comprising: a printhead that discharges the ink to form the dots; and a unit that relatively moves the printhead and the print medium. A gradation recording device according to any one of the above. 14. For each of a plurality of color inks,
The method according to any one of claims 7 to 13, wherein a plurality of inks having different densities are used, and the control unit records a multi-color gradation image using a plurality of ink dots for each color. Gradation recording device. 15. The recording head according to claim 1, further comprising: a recording head that discharges the ink to form the dots, wherein the recording head causes film boiling in the ink to discharge the ink. 15. The gradation recording apparatus according to claim 7, wherein the gradation recording apparatus has a body.