JP3291928B2 - Ink jet recording method, color image processing method, color image processing apparatus, ink jet recording apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to an ink jet recording method for recording a color image for each pixel using a plurality of inks of different colors, and an ink jet recording apparatus for recording a color image. The present invention relates to a possible color image processing method and apparatus, an ink jet recording method, a color image processing method, and an ink jet recording apparatus using the apparatus. In particular, it is possible to record a good image with no bleeding between colors on plain paper such as xerographic paper generally used in an electrophotographic copying machine or the like.

[0002]

2. Description of the Related Art In general, an ink jet printer that discharges a liquid ink droplet from a nozzle to record an image is known.
The simple configuration of the device allows it to be miniaturized and inexpensive to manufacture, and can record black and white and color images on plain paper such as report paper and copy paper. are doing.

A conventional ink jet printer uses an ejection energy generator, such as a piezoelectric element or an electrothermal conversion element, as an ejection drive source to eject ink droplets from nozzles and fly them, as shown in FIG. Besides paper,
A device capable of recording an image by adhering and absorbing the ink 101 onto a recording medium 100 made of plain paper such as report paper or copy paper, a film, cloth, or the like. , So that not only monochrome but also full-color image recording can be performed.

By the way, in order to perform full-color image recording in the above-described ink jet printer, fine particles such as SiO ₂ and CaO are formed on the surface in order to improve the absorption and fixing of the ink onto the recording medium and obtain a high-quality image. Is dispersed in a hydrophilic binder and coated on a recording base paper,
In many cases, recording paper dedicated to ink jet recording as a coat layer is used, and the cost for obtaining one print, so-called running cost, has been high.

On the other hand, in the above-described ink jet printer, full-color image recording is performed on a recording medium having poor ink absorbency, such as copy paper or report paper, which is generally used in an electrophotographic copying machine, instead of dedicated recording paper. In such a case, the following problems occur. In other words, when copy paper or report paper with poor ink absorbency is used as the recording medium, full-color ink is used by using a slow-drying ink that has relatively good image quality of characters and line images. When the image is recorded, as shown in FIG.
01 is not immediately dried, and the ink droplet 101 flows and diffuses, and the ink droplets printed next to each other are connected to each other, and bleeding called color bleeding occurs between adjacent ink droplets of different colors. In addition, there is a problem that color mixing occurs unintentionally and image quality of a color image is degraded.

Further, when copy paper or report paper or the like having poor ink absorbency is used as the recording medium and ink that is relatively dry and permeates relatively quickly is used as the ink, the color space in a full-color image can be reduced. Although bleeding can be suppressed, as shown in FIG.
01 penetrates deeply into the recording medium and no color material remains on the paper surface. Therefore, the printing area of the ink droplet 101 has a low density and a narrow color reproducibility range, and the outline of the dot remains unchanged. As a result, the outline of the character / line image becomes jagged, and there is a problem that the image quality is greatly deteriorated.

As described above, in the above-described conventional ink jet printer, when a recording medium having a low ink absorption other than the recording paper dedicated to ink jet recording is used, both the full-color image and the character / line image are improved in image quality. There was a problem that it was very difficult. Therefore, in the conventional ink jet recording method, it is necessary to use a recording paper dedicated to ink jet recording as a recording medium, and the cost for obtaining one print, so-called running cost, becomes high. It was also an obstacle to its widespread use.

Therefore, as shown below, many techniques that can be used to solve the above problems have been proposed.

First, in the case of the ink jet recording apparatus disclosed in Japanese Patent Application Laid-Open No. 4-355157, at least one color ink jet recording apparatus which performs color image recording using a plurality of inks of different colors is used. The ink composition differs so that the permeability of one ink into the recording medium is different from the permeability of the other ink.

In the case of the ink jet recording apparatus disclosed in Japanese Patent Application Laid-Open No. 4-364951, a color ink jet recording apparatus in which color images are recorded by using a plurality of recording means using inks of different colors, The ink composition is different so that the fixability of at least one ink to a recording medium is different from the fixability of other inks. Further, the ink jet recording apparatus according to this proposal also includes a configuration in which the fixing speed of the ink that is applied first to the recording medium is faster than the fixing speed of the ink that is applied later.

Further, in the above-mentioned ink jet printer, the priority is given to the image quality of the color image, the quick drying of the color ink is enhanced, and the occurrence of intercolor bleeding called color bleeding is prevented, so that a good color image can be recorded. For this purpose, a surfactant such as disclosed in JP-B-62-11781 or a block copolymer of propylene oxide and ethylene oxide as proposed by the present applicant (Japanese Patent Laid-Open No. JP-A-325574) has been attempted to increase the penetrating power of ink by adding it to ink.

On the other hand, in the color separation method in the ink jet type color graphic printing disclosed in US Pat. No. 5,168,552, a composite black made of CMY is replaced with K (black) in order to suppress a decrease in black print density. The data is converted into data, and the black ink within the minimum interval is detected from the chemical characteristics of the ink.

In the case where the ink having quick drying properties is used for all colors, as shown in FIG. 54, the ink penetrates much in the depth direction of the paper, so that the print density on the surface of the paper decreases. Therefore, since the image quality of characters and line images recorded with black ink deteriorates, a color ink jet printer using a combination of cyan, magenta, and yellow color inks and black ink has a particularly high print density. Because of the necessity of recording characters, only the black ink has low permeability.

Although the present application claims a priority, the color ink jet recording method disclosed in International Publication WO93 / 24330 published after the filing date of the application on which the priority is claimed is applied at 20 ° C. Has a surface tension of 40 dy
Using a plurality of color inks of less than n / cm and a black ink having a surface tension at 20 ° C. of 40 dyn / cm or more, first, in a black printing area, which is in contact with the color portion, at least one color Is printed, and then black ink is printed to obtain a sharp and clear color image with little bleeding.

[0015]

However, the above-mentioned prior art has the following problems. JP 4
With the difference in the degree of permeability shown in the ink jet recording apparatus of JP-A-355157, there is a limit to compatibility between a color image having no bleeding between different-color image areas and a sharp image.

Further, as disclosed in the ink jet recording apparatus disclosed in Japanese Patent Application Laid-Open No. 4-364951, the fixing property of at least one ink on a recording medium is different from the fixing property of another ink. If the ink composition is different and the fixing speed of the ink that is applied first to the recording medium is set to be faster than the fixing speed of the ink that is applied later, the ink is regarded as a part already recorded. There is a problem that the ink penetrates into the already-recorded area unevenly and causes intercolor bleeding because the penetration speed of the ink with a low fixing speed that is later injected is greatly different from the non-printed part. Was found in the experiments of the present inventors. The phenomenon in which the ink with a low fixing speed that is subsequently ejected is unevenly drawn to the already recorded area and causes intercolor bleeding does not occur only at a few dots at the boundary of the ink with a low fixing speed. This phenomenon occurs as a phenomenon of the entire area recorded with ink having a low fixing speed. Further, since the ink having a low fixing speed to be subsequently ejected is unevenly drawn to the already recorded area, an area having a low density occurs in the recording area formed by the ink having a low fixing speed, and the image quality is further degraded. There is also a problem.

Further, in the above-described conventional ink jet printer, when a highly permeable ink is used as the color ink and a low permeable ink is used as the black ink, the image area of the highly permeable ink is reduced. When the image area of the low-permeability ink contacts the plain paper on the plain paper, the low-permeability ink diffuses into the image area of the high-permeability ink as shown in FIG. Color mixture (bleeding) occurs,
There has been a problem that image quality is deteriorated.

Therefore, the present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to eliminate the use of special recording paper dedicated to ink-jet recording and to reduce the use of ordinary paper such as copy paper. An ink jet recording method, a color image processing method, an apparatus thereof, and an ink jet recording method capable of preventing the occurrence of color bleeding between images of different colors while realizing the recording of images such as characters with high density and sharp edges even on paper. It is an object of the present invention to provide a recording method, a color image processing method, and an ink jet recording apparatus using the apparatus.

[0019]

According to a first aspect of the present invention, there is provided an ink jet recording method for recording a color image using a black ink having low permeability and a color ink having high permeability. As for the pixels to be printed, some of the pixels are printed with ink dots using black ink, and the pixels to be printed in black adjacent to some of the pixels are printed in color instead of black. And printing with color ink dots using any one of the above-mentioned inks.

According to a second aspect of the present invention, there is provided the ink jet recording method according to the first aspect, wherein the color ink dots used for printing one pixel at a time adjacent to the partial pixels to be printed in black are used. Is characterized in that ink dots of all colors are used.

According to a third aspect of the present invention, there is provided an ink jet recording method for recording a color image using black ink having low permeability and color ink having high permeability.
For pixels to be printed in black, some of the pixels are printed with ink dots using black ink, and pixels to be printed in black adjacent to some of the pixels are replaced with black printing. And printing by overlapping color ink dots using any two of the color inks.

According to a fourth aspect of the present invention, there is provided an ink jet recording method for recording a color image using black ink having low permeability and color ink having high permeability.
For pixels to be printed in black, some of the pixels are printed by overlapping ink dots using black ink and color ink dots using any one of the color inks, respectively. Pixels to be printed in black adjacent to the pixels of the set are empty dots that are not printed.

According to a fifth aspect of the present invention, there is provided an ink jet recording method for recording a color image using black ink having low permeability and color ink having high permeability.
For pixels to be printed in black, some of the pixels are printed by superimposing an ink dot using black ink and a color ink dot using any two colors of color ink. Pixels to be printed in black adjacent to the pixels of the set are empty dots that are not printed.

According to a sixth aspect of the present invention, in the ink jet recording method according to any one of the first to fifth aspects, the brightness of the low-permeability black ink is higher than that of the higher-permeability color ink. The brightness is lower than the brightness.

According to a seventh aspect of the present invention, in the ink jet recording method according to any one of the first to sixth aspects, the black ink having low permeability has an absorption coefficient (Ka) of 0.5 ml / m 2. ² ms ^1/2 or less, the wetting time (Tw) is 50 to 200 msec, and the absorption coefficient (Ka) of the highly permeable color ink is 1.0 ml / m ² ms
It is characterized in that the wetting time (Tw) is not more than ^1/2 and the wetting time (Tw) is not more than 20 msec.

An eighth aspect of the present invention is a color image processing method for processing a color image when recording a color image using black ink having low permeability and color ink having high permeability. Therefore, some of the pixels to be printed in black are printed with ink dots using black ink, and the pixels to be printed in black adjacent to the some pixels are each black. Instead of printing, black image data is converted so that printing is performed using color ink dots using any one of the color inks.

According to a ninth aspect of the present invention, there is provided a color image processing method for processing a color image when recording a color image using black ink having low permeability and color ink having high permeability. Therefore, some of the pixels to be printed in black are printed with ink dots using black ink, and the pixels to be printed in black adjacent to the some pixels are each black. Instead of printing, black image data is converted so that color ink dots using any two of the color inks are printed in a superimposed manner.

According to a tenth aspect of the present invention, there is provided a color image processing method for processing a color image when recording a color image using black ink having low permeability and color ink having high permeability. Some of the pixels to be printed in black are printed by superimposing an ink dot using black ink and a color ink dot using one of the color inks. The pixel to be printed in black adjacent to some of the pixels is converted from black image data so as to be an empty dot not to be printed.

An eleventh aspect of the present invention is a color image processing method for processing a color image when recording a color image using black ink having low permeability and color ink having high permeability. Some of the pixels to be printed in black are printed by superimposing an ink dot using black ink and a color ink dot using one of two colors of color ink. The pixel which is to be printed in black adjacent to some of the pixels is converted into black image data so as to be an empty dot not to be printed.

According to a twelfth aspect of the present invention, there is provided a color image processing apparatus for processing a color image when recording a color image using black ink having low permeability and color ink having high permeability. Therefore, some of the pixels to be printed in black are printed with ink dots using black ink, and the pixels to be printed in black adjacent to the some pixels are each black. An image data conversion means for converting black image data so that printing is performed using color ink dots using any one of the color inks instead of printing.

According to a thirteenth aspect of the present invention, there is provided a color image processing apparatus for processing a color image when recording a color image using black ink having low permeability and color ink having high permeability. Therefore, some of the pixels to be printed in black are printed with ink dots using black ink, and the pixels to be printed in black adjacent to the some pixels are each black. The image processing apparatus further includes image data conversion means for converting black image data so that color ink dots using any two of the color inks are printed in place of printing.

According to a fourteenth aspect of the present invention, there is provided a color image processing apparatus for processing a color image when recording a color image using black ink having low permeability and color ink having high permeability. Some of the pixels to be printed in black are printed by superimposing an ink dot using black ink and a color ink dot using one of the color inks. The image processing apparatus further comprises image data conversion means for converting black image data so that pixels to be printed in black adjacent to some of the pixels are empty dots not to be printed.

According to a fifteenth aspect of the present invention, there is provided a color image processing apparatus for processing a color image when recording a color image using black ink having low permeability and color ink having high permeability. Some of the pixels to be printed in black are printed by superimposing an ink dot using black ink and a color ink dot using one of two colors of color ink. The image processing apparatus further comprises image data conversion means for converting black image data so that pixels to be printed in black adjacent to some of the pixels are empty dots not to be printed.

According to a sixteenth aspect of the present invention, in an ink jet recording apparatus, control is performed such that printing is performed in accordance with the image data converted by the color image processing apparatus according to any one of the twelfth to fifteenth aspects. It is characterized by having means.

[0035]

[0036]

[0037]

[0038]

[0039]

According to the present invention, since the unit pixel is a dot matrix composed of the ink dots having low permeability and the ink dots having high permeability, the ink having low permeability and the ink having high permeability in the unit pixel are used. The ink is diffused and mixed with each other, so that high ink permeability is maintained for one pixel as a whole. As a result, even if a pixel region consisting of only highly permeable ink is in contact with the pixel region, the ink is diffused and color mixture (bleeding) occurs. There is no. At this time, by configuring the dot matrix such that four sides of the ink dots having low permeability are adjacent to the ink dots having high permeability, it is possible to instantaneously mix the two types of ink. Further, in order to keep the black image quality within an allowable range, it is possible to increase the ratio of black ink having low permeability as much as possible. As a result of our research, it was found that the ratio of the ink dots having a high permeability to the ink dots having a low permeability was 50 to 200% in a range satisfying the above. Further, in the case where the unit pixel is composed of an ink dot in which an ink dot having low permeability and an ink dot having high permeability are overlapped, and an empty dot where ink is not applied, the empty ink corresponding to the overlapped ink dot is similarly used. It has been found that the dot ratio of 0 to 100% is a condition under which image quality deterioration such as bleeding between colors or white spots can be suppressed and an image quality within an allowable range can be obtained.

In a color image processing method for processing a color image when recording a color image using black ink having low permeability and color ink having high permeability, printing is performed using black ink droplets. It is configured to convert a part of the black image data into color image data so that printing is performed by replacing part of the part to be printed with color ink droplets. If printing is performed in accordance with the data, as described above, the low-permeability ink and the high-permeability ink of the adjacent pixels are diffused and mixed with each other, and the high ink permeability of one pixel as a whole is maintained. Even if a pixel region composed of only ink is present in contact with the pixel region, the pixel region is not diffused and mixed (bleeding) does not occur. At this time, by printing such that the ink dots having high permeability are adjacent to the ink dots having low permeability, it is possible to instantaneously mix the two types of ink.

In order to keep the black image quality within an acceptable range, a part of a portion to be printed with black ink droplets is formed by superimposing black ink droplets having low permeability and color ink droplets having high permeability. By performing printing in place of printing, it is possible to convert a black image into image data that can be recorded more clearly.

[0042]

As described above, a portion of a portion to be printed using low-permeability ink is printed using high-permeability ink adjacent to or overlaid with dots made of low-permeability ink. Can prevent bleeding, etc., but as a printing order of low-permeability ink and high-permeability ink to be printed adjacently or overlaid,
The ink having a high permeability may be applied after the ink having a low permeability is applied, or the ink having a low permeability may be applied after applying the ink having a high permeability. When hitting the ink having a high permeability after hitting the ink having a low permeability, the ink having a low permeability, which has been hit first,
The ink rapidly penetrates the recording paper together with the ink having high permeability that is later struck, and is fixed as if it has high permeability. Also, when the low-permeability ink is applied after the high-permeability ink is applied, the state of the recording paper surface changes because the high-permeability ink that has been applied first penetrates the recording paper. Thus, the ink permeability is improved as compared with the state where nothing is recorded. For this reason, even if ink having low permeability is later ejected, the ink immediately penetrates, so that bleeding due to color mixture at a color boundary or the like can be minimized.

The above-described ink jet recording method, color image processing method, and apparatus therefor use, for example, one print head for printing with ink having low permeability and printing for different colors with ink having high permeability. The present invention can be applied to an ink jet recording apparatus that performs recording using four print heads of three print heads. Alternatively, recording is performed using a first print head that performs printing with ink having low permeability and a second print head in which portions that perform printing of different colors with a plurality of inks having high permeability are arranged in series. The present invention can be applied to an inkjet recording apparatus that performs the following.

Here, the ink permeability is represented by an absorption coefficient (Ka) and an ink wetting time (Tw).
Absorption coefficient (Ka) and ink wetting time (Tw) are J
apan Tappi Paper Pulp Test Method No. 51
Measured by BristowTester according to -87. In the measurement, as shown schematically in FIG. 55, a fixed amount of ink is put in a head box, and the ink is transferred to a paper stuck around a rotatable cylinder to determine the transfer amount. By changing the rotation speed of the cylinder, the contact time is reduced to 0.1.
The transfer amount for 004 to 2 seconds can be measured. An example of a graph showing the relationship between the contact time and the transfer amount is shown in FIG. here,
The contact time is shown on the scale as the square root of time. The slope of this graph becomes the absorption coefficient (Ka), and the contact time is 0 s.
The ink transfer amount at ec is called a roughness coefficient (Vr),
It represents the amount of ink entering the irregularities on the paper surface. In addition, there is a time (Tw) during which ink absorption does not occur at the initial stage of contact, and this portion is called an ink wetting time. It is the time required for the paper to be wet by the ink.

Further, the absorption coefficient (Ka) is expressed by Rucas-
The Washborn equation (the following equation) matches the coefficient when the absorption time (t) is used as a parameter.

V = (ε / τ) {(rcosθ) · γt / 2η} where V: ink absorption amount per unit time ε: void ratio of paper τ: bending ratio of capillary on paper surface r: paper Surface capillary diameter cos θ: contact angle between paper and ink γ: surface tension of ink t: ink absorption time η: ink viscosity

That is, the ink absorption coefficient (Ka) is determined by the state of the paper surface, the physical properties of the ink, and the wettability between the ink and the paper.

The ink absorption coefficient (K
a) becomes large. Further, the temperature of the ink adhering to the paper instantaneously rises and the ink viscosity η decreases, so that the ink absorption coefficient (Ka) also increases. On the other hand, the ink wetting time (Tw) is affected by the wettability between the ink and the paper, that is, the contact angle between the paper and the ink and the surface tension of the ink.
The ink wetting time (Tw) is substantially determined by the ink and the paper itself.

[0050]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on the illustrated embodiment.

FIG. 1 shows an embodiment of an ink jet recording apparatus to which the ink jet recording method according to the present invention can be applied.

In FIG. 1, reference numeral 1 denotes a recording head. This recording head 1 has four recording sections 1a, 1a and 1 corresponding to four colors of black, cyan, magenta and yellow.
b, 1c and 1d. These recording units 1a, 1
b, 1c, and 1d serve as recording media by ejecting black, cyan, magenta, and yellow inks from nozzles provided on the lower end surface (in FIG. 1) of the head 1 in accordance with image information. The recording of an image on the recording paper 2 is performed. In addition, black, black,
Ink tanks 3, 4, 5, and 6 containing cyan, magenta, and yellow inks are integrally mounted, and the recording units 1 a, 1 b, and 1.
A power supply signal cable 7 for transmitting a head drive signal generated by binarizing color image data of each color of black, cyan, magenta, and yellow into a dot pattern is connected to c and 1d. .

Further, the recording head 1 is fixed to a head carriage 8.
Are slidably mounted on the two guide rods 9 along the main scanning direction. The head carriage 8
, The end of the timing belt 10 is connected,
The timing belt 10 is wound around a drive pulley 12 that is driven to rotate by a drive motor 11. The inkjet recording apparatus is fixed to the head carriage 8 by rotating the driving motor 11 at a predetermined timing to move the head carriage 8 along the main scanning direction via the timing belt 10. The recording head 1 records an image of a predetermined color on the recording paper 2. Note that each of the recording sections 1a, 1b, 1c, and 1d of the recording head 1 has
For example, 256 nozzles arranged in a direction perpendicular to the scanning direction of the head carriage 8 are provided in one row at a density of 400 nozzles per inch.

A platen (not shown) made of a thin metal plate or the like is fixedly disposed below the recording head 1, and the recording paper 2 is transported on the platen by a paper feed transport roller (not shown). The sheet is conveyed at a predetermined timing in the direction of the arrow.

Further, the ink tanks 3, 4, 5, 6
Are filled with black ink having low permeability and color inks of cyan, magenta, and yellow having high permeability in order.
It is configured to supply black, cyan, magenta, and yellow inks to b, 1c, and 1d.

In the ink jet recording apparatus, the drive motor 11 moves the head carriage 8 from left to right in FIG. To record an image on the recording paper 2.
At this time, the driving circuit of the recording head 1 is driven by the dot data obtained by developing the color image data into a dot pattern. When the recording of one line is completed, the recording paper 2 is transported by one sheet by a paper feed transport roller (not shown). Only sent. During this time, the recording head 1 is returned to the left side in FIG. 1 again to start the next recording.

In this embodiment, the recording head 1
The unit pixels on which the recording units 1a, 1b, 1c, and 1d perform recording are configured as a dot matrix including low-permeability ink dots and high-permeability ink dots. Here, as the ink dots with low permeability, for example, those made of black ink are used, and as the ink dots with high permeability, for example, those made of color inks such as cyan, magenta, and yellow are used. It is. Further, the low permeability ink has an absorption coefficient (Ka) of 0.5 ml / m ² · ms
^The ink having a wetting time (Tw) of 50 to 200 msec or less is used, and an ink having a high permeability has an absorption coefficient (Ka) of 1.0 ml / m ² · ms.
Those having a ^half or more and a wetting time (Tw) of 20 msec or less are used.

As such an ink, for example, FIG.
Those having the composition and characteristics as shown in (1) are used. As the recording paper 2 on which an image is recorded with these inks, L paper manufactured by Fuji Xerox Co., Ltd., which is a copy paper having characteristics as shown in FIG. 3, is used.

In this embodiment, as shown in FIG. 4, the unit pixel 20 is composed of a 4 × 4 dot matrix 21. However, the unit pixel 20 is not limited to this, and may be 2 × 2 or 3 × 2.
Of course, it may be composed of another dot matrix 21 such as x3, 3x4, 8x8.

FIG. 5 shows an embodiment of the ink jet recording method according to the present invention. In the first specific example, as shown in FIG. 5, when the black image 22 and the cyan image 23 are adjacent to each other, the black and cyan ink The color image area 22 in which the same number of dots 24 and 25 are alternately arranged vertically and horizontally is adjacent to each other. That is, in the specific example 1, a cyan ink dot 24 composed of a highly permeable ink dot is printed next to a black ink dot 25 composed of a low permeable ink dot. Thus, as shown in FIG. 6, the ink dots 25 made of black ink having low permeability have been mixed with the cyan ink dots 24 having high permeability printed adjacent to each other. Since the black ink dots 25 having low permeability have the same permeability as the cyan color having high permeability, the black image dots 22
There is no bleeding between colors between the ink dots 24 and the cyan ink dots 24. In addition, characters and line images having no color image in the background are black ink dots 25 having low permeability.
Since printing is performed only by the black ink dots 25 on the recording paper 2, the black ink dots 25 are connected to each other, and a good image having excellent edge and linearity can be recorded.

Since the black image area 22 has a color that is a mixture of black and cyan, the black color has a slightly bluish color. Did not occur. Further, the image quality of black characters and lines on the background of the color ink was good. FIG. 7 shows a color image in which the same number of black and cyan ink dots 25 and 24 are alternately arranged both vertically and horizontally on a white background. As shown in the specific example 1 of FIG. 8A, it was possible to perform recording with quick drying without bleeding. 5 to 12 show only unit pixels adjacent to the boundary.

Example 2 In Example 2, although the arrangement of the ink dots is similar to that of Example 1, the ratio of cyan dots is higher than that of Example 1. That is, in the specific example 2, FIG.
As shown in FIG. 5, in a unit pixel of 4.times.4 = 16, 10 black dots and 6 cyan dots are printed.

In this specific example 2, the black image area is more bluish but within an acceptable range, and no intercolor bleeding occurs. Further, the image quality of black characters and lines on the background of the color ink was good.

Specific Example 3 In the specific example 3, the arrangement of the ink dots is similar to that of the specific example 1, but the ratio of the black dots is further increased as compared with the specific example 1. That is, in the specific example 3, FIG.
As shown in (A), in 4 × 4 = 16 unit pixels, 8 black dots are printed for 12 black dots, and the black dots are partially overlapped with the cyan dots. It is what was constituted.

In Example 3, the bluishness of the black color is considerably suppressed, and no intercolor bleeding occurs. The image quality of black characters and lines with a cyan background was good.

Example 4 Example 4 is an example in which the cyan dots of Example 1 are replaced with cyan, magenta, and yellow, as shown in FIG. 9. As shown in FIG. Was as good as the result of Example 1, and the black color was further improved than that of Example 1. The image quality of black characters and lines against a color image was good.

Embodiment 5 In Embodiment 5, although the arrangement of the ink dots of Embodiment 4 is similar, as shown in FIG. 8B, the ratio of the color ink dots is increased. The black tint was improved, and no intercolor bleeding occurred. Further, as in the specific example 4, the image quality of black characters and lines with a color image as a background was good.

Comparative Example 1 In Comparative Example 1, the arrangement of the ink dots was similar to that of Example 1, but the ratio of black ink dots was increased. In Comparative Example 1, as shown in FIG. 8A, intercolor bleeding occurred, and the image quality of black characters and lines with cyan as a background was unacceptable.

Comparative Example 2 In Comparative Example 2, contrary to Comparative Example 1, the ratio of cyan ink dots was increased. In Comparative Example 2, FIG.
As shown in (A), although there was no intercolor bleeding, the bluish black was strong and black was not recognized.

Comparative Example 3 In Comparative Example 3, the arrangement of the ink dots was similar to that of Examples 4 and 5, but the dot ratio of the black ink was increased. In Comparative Example 3, as shown in FIG. 8B, intercolor bleeding occurred, and the image quality of black characters and lines having a color background was unacceptable.

Comparative Example 4 In Comparative Example 4, contrary to Comparative Example 3, the ratio of color ink dots was increased. In Comparative Example 4, FIG.
As shown in (B), no bleeding between colors occurred, but the image quality itself of black characters and lines did not fall within the allowable range.

Further, a case of using a dot matrix composed of ink dots in which low-permeability ink dots and high-permeability ink dots are overlapped and empty dots that have not been struck will be described in the sixth embodiment.

Specific Example 6 In this specific example 6, as shown in FIG. 10B, an ink dot 26 in which a black ink dot 25 and a cyan ink dot 24 overlap each other as shown in FIG. Arrange every other dot both vertically and horizontally, and ink dot 2
6 are empty dots. The print quality was the same as in Example 1 as shown in FIG. FIG. 11 shows an image in which black and cyan ink dots are arranged vertically and horizontally at every other dot without adjoining different color areas, and an image of a dot matrix composed of empty dots without ink dots is formed on a white background. Shown in
A quick-drying recording without bleeding was possible. FIG.
In (B), the black ink dots 25 are recorded first, and the cyan ink dots 24 are recorded later.
Conversely, the same effect could be obtained by recording cyan ink dots 24 first and black ink dots 25 later.

Comparative Example 5 In Comparative Example 5, the black ink dots and the cyan ink dots were 6 in comparison to the specific example 6, and as shown in FIG. W) occurred, and disconnection of lines and the like, and the quality of a uniform pattern deteriorated.

In the above description, the print dot pattern in the black print area has been described. Hereinafter, image processing for creating these print dot patterns will be described. Also in the following description, a case will be described in which low-permeability ink is used as black ink and cyan, magenta, and yellow colors having high permeability are used as color inks.

As described above, in order to print each color such as cyan, cyan, magenta, and yellow on a black recording area, a part of a portion to be printed with black ink droplets is printed with color ink droplets. It is configured to be replaced and printed. Therefore, for example, according to the conversion rule shown in FIG. 13, the printing of a solid black image having a size of 4 pixels in both the vertical and horizontal directions is converted. Then, the input image as shown in FIG. 14A is printed as shown in FIG. In this case, a 4 × 4 filter as shown in FIGS. 15A to 15D is used. Note that the conversion rule shown in FIG. 13 is such that a part of a portion to be printed with black ink droplets is replaced with a printing with cyan, magenta, and yellow ink droplets and printing is performed so that a part of black image data is printed. Is converted into cyan, magenta, and yellow image data. Therefore, the conversion rule shown in FIG.
When a matrix of 4 = 16 is printed in a predetermined order using a known area gradation method, the dots to be printed first to eighth are set to black as they are, and the ninth to sixteenth dots are printed.
The dot to be printed second is replaced in the order of cyan, magenta, and yellow. However, the present invention is not limited to this. The ninth and subsequent dots may be replaced with three cyan dots, three magenta dots, and two yellow dots, or a combination of dots of other colors or all of the same color. You may comprise so that it may replace with a dot etc. As described above, the size of the matrix is 4 × 4
It is not limited to. Therefore, the filter may be determined according to the size of the set matrix.

FIG. 16 is a block diagram showing an embodiment of a color image processing apparatus to which the color image processing method according to this embodiment is applied.

In the figure, reference numeral 30 denotes black input image data inputted in binary of "0" and "1", 31 denotes cyan input image data inputted in binary of "0" and "1", and 32 Is the input image data of magenta which is also input as binary of “0” and “1”, and 33 is the input image data of “0” and “1”.
5 shows yellow input image data input by value.

When the input image is divided into 4 × 4 dot matrices, each of the dots (i, j) of each 4 × 4 dot matrix has a different color from the black dot. A filter for a black image in which dots to be replaced are stored in advance, 35 is a filter for each 4 × 4 dot matrix when the input image is divided into 4 × 4 dot matrices.
Each dot (i, j) of a × 4 dot matrix
In, a filter for a cyan image in which dots to be replaced with cyan among black dots are stored in advance,
Reference numeral 36 denotes a magenta image in which, when the input image is divided into 4 × 4 dot matrices, in each dot (i, j) of each 4 × 4 dot matrix, dots to be replaced with magenta among black dots are stored in advance. The image filter 37 is a dot to be replaced with yellow among black dots in each dot (i, j) of each 4 × 4 dot matrix when the input image is divided into 4 × 4 dot matrices. Are respectively stored in the filter for yellow image in which is stored in advance. Filters 34 to 37 for these colors
Is constituted by, for example, a ROM in which predetermined data is stored in advance.

Reference numeral 38 denotes a parameter indicating the dot position (i, j) of each input image data for one page of black, cyan, magenta, and yellow, where i is the dot position of the horizontal image, and j is j. It shows the dot position of the image in the vertical direction. Here, the parameter 38 indicating the dot position (i, j) of the input image data is set to the dot position (i, j) of the input image data because it is necessary to divide the entire input image data into a 4 × 4 dot matrix.
j) is represented by a binary number, and the dot position (i, j) of the input image data represented by the binary number is obtained by dividing the dot position (i, j) of the actual input image data by 4. The value indicates the remainder. As a result, the dot position (i, j) of the input image data actually used as the parameter 38 is set to a value indicating the remainder obtained by dividing the dot position (i, j) of the actual input image data by 4. , 2
Dot position (i,
Only the lower two bits of j) are used. For example, if the dot position (i, j) of the actual input image data under consideration is (5, 5), the dot position (0000101, 0) of the input image data expressing this in binary.
Only the value of the lower two bits (01, 01) of (000101) is used as the actual parameter 38.

Reference numeral 39 denotes black input image data 3
An AND circuit which takes the logical product of 0 and the output data of the black image filter 34, an AND circuit 40 which takes a logical product of the black input image data 30 and the output data of the cyan image filter 35, 41 is a black circuit AND circuit for calculating the logical product of the input image data 30 and the output data of the filter 36 for the magenta image; and 42, the black input image data 30 and the filter 37 for the yellow image
AND circuit 43 which takes the logical product with the output data of
An OR circuit for ORing the D circuit 40 and the input image data 31 for cyan, an OR circuit 44 for ORing the AND circuit 41 and the input image data 32 for magenta, and 45 for AN
3 shows OR circuits for calculating a logical sum of the D circuit 42 and the input image data 33 of yellow.

Reference numeral 46 denotes black output image data from the AND circuit 39, 47 denotes cyan output image data from the OR circuit 43, and 48 denotes the OR circuit 44.
And magenta output image data 49 from the OR circuit 45, respectively. As shown in FIG.
c and 1d are respectively applied at predetermined timings.

The above black, cyan, magenta,
The input of each of the yellow input image data 30 to 33 and the output of each of the output image data 46 to 49 are performed for each page of the image data of one page, even if they are performed for each line. Or both. In this case, black, cyan,
Needless to say, a latch circuit or a memory circuit for temporarily storing the magenta and yellow input image data 30 to 33 and the output image data 46 to 49 is used.

With the above arrangement, the ink jet recording apparatus according to this embodiment records a color image as follows. That is, the above-mentioned ink jet recording apparatus receives black, cyan, magenta,
Four color recording image data of yellow, that is, input image data 3 of black, cyan, magenta, and yellow
0-33 are sent. Then, when recording image data is sent from the outside, the inkjet recording apparatus converts the input image data 30 to 33 corresponding to each color of black, cyan, magenta, and yellow into color image processing as shown in FIG. The apparatus performs predetermined image processing.

In this color image processing apparatus, as shown in FIG. 16, bit positions (i, j) of input image data for input image data 30 to 33 corresponding to black, cyan, magenta, and yellow, respectively. Parameter 3 indicating
In accordance with 8, predetermined filter processing is performed by filter circuits 34 to 37 corresponding to each color of black, cyan, magenta, and yellow, and a logical product of the data after the filter processing and the input image data 30 to 33 or A logical sum is generated by an AND circuit and an OR circuit, and image data 46 to 49 corresponding to each color of black, cyan, magenta, and yellow are output.

Further, the image processing operation of the color image processing apparatus will be described in detail with reference to a specific example.

First, as input image data 30 to 33,
As shown in FIG. 17A, consider an image 50 of 8 × 8 pixels in which cyan and magenta images are separated by a black oblique line and a horizontal line. When the input image data of this color image is decomposed into black, cyan, and magenta image data 30 to 32, FIG.
(D). By the way, in the case of the image shown in FIG. 17A, since there is no yellow image, the input image data 33 corresponding to yellow is all “0”.

Next, the respective input image data 30 to 33 of black, cyan, magenta and yellow (not shown) shown in FIGS. Image processing. First, the input image data 31 of cyan of 8 pixels × 8 pixels is obtained from a parameter 38 indicating the bit position (i, j).
Is a filter 3 for cyan as shown in FIG.
5, a portion of the black image data where a cyan dot is to be printed is obtained. This cyan filtered output data 51 (FIG. 18B)
Is input to one of the AND circuits 40, and the black input image data 30 is input to the other of the AND circuits 40.
The logical product is obtained between (FIG. 18A). This AND
The output data 52 (FIG. 18C) of the circuit 40 is shown in FIG.
As shown in FIG. 18, cyan input image data 31 (FIG. 18)
(D)) is ORed by the OR circuit 43 to obtain cyan output image data 47 as shown in FIG.

The above-described cyan input image data 3
Similar to 1, the same image processing is performed on the magenta and yellow input image data 32 and 33. That is, the bit information (i, j) of the input image data is
Through magenta and yellow filters 36 and 37 as shown in FIG. 9 (B) or FIG. 20 (B), a portion of the black image data where magenta and yellow dots are to be printed is obtained. The output data 53 and 54 processed by the magenta and yellow filters 36 and 37 (FIG. 19B or FIG. 20B).
Is ANDed between the black input image data 30 (FIG. 19 (A) or FIG. 20 (A)) input to one of the AND circuits 41 and 42 and input to the other of the AND circuits 41 and 42. Is taken. These AND circuits 41 and 42
Output data 55, 56 (FIG. 19C or FIG. 20).
(C)), as shown in FIG. 16, a logical sum is generated by the OR circuits 44 and 45 between the magenta and yellow input image data 32 and 33 (FIG. 19 (D) or FIG. 20 (D)). The magenta and yellow output image data 48 and 4 shown in FIG.
9 is obtained.

Further, the black input image data 30 shown in FIG. 17B is subjected to image processing in the color image processing apparatus as follows. In the input image data 30 of 8 pixels × 8 pixels of black, the parameter 38 indicating the bit position (i, j) passes through a black filter 34 as shown in FIG. A portion of the data to be printed with dots of another color is required. The output data 57 (FIG. 21B) that has been subjected to the black filter processing is supplied to the AND circuit 39.
Of the black input image data 30 (FIG. 21A) which is input to one of the AND circuits 39 and is input to the other of the AND circuit 39. The output data of the AND circuit 39 is directly output as black output image data 46 as shown in FIG. 16, and black output image data 46 as shown in FIG. 21C is obtained.

In this way, image data 46 to 49 that have been subjected to predetermined image processing by the color image processing apparatus are obtained. As shown in FIG.
C and 1d are applied at predetermined timings, and a color image as shown in FIG. 22A is recorded on the recording paper 2 by ink dots.

By performing the above processing, the image to be printed with the black ink having the low permeability according to the conversion rule of FIG. 13 is combined with the black ink K having the low permeability as shown in FIG. Printing can be performed using a combination of color inks C such as cyan, which has high permeability, and by mixing the black ink K and the color ink C, the ink penetration speed of the black print portion can be increased. Therefore, it is possible to reduce the bleeding of the ink at the boundary between the black printed portion and the color printed portion, and to record a color-free image between black and color, and a color image processing method therefor. An apparatus can be provided.

Further, since a low-permeability ink is used as the black ink and a high-permeability ink is used as the color ink, a high-density black image with sharp edges can be recorded even on plain paper. can do.

FIG. 23 shows a second embodiment of the color image processing method according to the present invention. The image processing for the input image data is not performed by a hardware circuit configuration, but is performed by a software configuration.

That is, in the color image processing apparatus according to this embodiment, as shown in FIG. 23, a CPU 60, an image memory 61 for storing image data of each color, and a filter for storing filter data corresponding to an image of each color. A memory 62 and a ROM 63 storing a predetermined program and the like are provided.

In the color image processing apparatus according to this embodiment, predetermined image processing is performed on input image data as follows.

First, with the start of the color image processing operation, as shown in FIG. 24, (i, j) corresponding to the bits of the input image data 30 to 33 of black, cyan, magenta, and yellow are respectively set. After setting to 0 (step 71), the image data k, c, m, and y of the pixel at the position (i, j) are read from the image memory 61 (step 72). Next, read corresponding to the bits of the input image data 30 to 33 (i, j) filter constant f _k determined by, f _c, f _m, the f _y from the filter memory 62 (step 73). Here, the filter constants f _k , f _c , f _m , stored in the filter memory 62,
As f _y , for example, as shown in FIG. 25, a value in which image filter values of each color of black, cyan, magenta, and yellow in hexadecimal system are recorded in advance corresponding to a dot matrix in units of 8 pixels is used. .

Thereafter, the CPU 60 determines the image data k, c, m, y and the filter constants f _k , f _c , f _m , f
_A logical product (AND) and a logical sum (OR) are calculated from the value of _y , and the calculation results are sequentially written to the image memory 61 (step 74). Further, 1 is added to the parameter i (step 75), and it is determined whether or not the value of i is equal to or greater than a predetermined value m (step 76). If the value of i is equal to or greater than m, While adding 1 to the value of j, it is determined whether or not the value of j is equal to or greater than a predetermined value n (step 7).
7) If n or less, the above operation is repeated.

By doing so, similarly to the above embodiment, FIG. 18 (E), FIG. 19 (E), FIG.
Output image data 46 to 49 as shown in FIG.

The other constructions and operations are the same as those of the above-described embodiment, and a description thereof will be omitted.

FIG. 26 shows a third embodiment of the color image processing method according to the present invention. The same parts as those in the above embodiment are denoted by the same reference numerals and described. It is configured to use a conversion rule that replaces pixels for printing black ink dots with printing by superimposing black and color ink dots. When a black solid print having a size of 4 pixels in both the vertical and horizontal directions is converted in accordance with the conversion rule shown in FIG. 26, the input image as shown in FIG. 27A is printed as shown in FIG.

This conversion can also be realized by hardware as shown in FIG. In this case, a 4 × 4 filter as shown in FIGS. 28 (A) to (D) is used. It should be noted that it can also be realized by software as shown in FIG.

The actual process of converting an image will be described with reference to an image of 8 × 8 pixels. First, input image data 3
As shown in FIG. 29A, an 8-pixel × 8-pixel image 50 in which cyan and magenta images are separated by a black oblique line and a horizontal line as shown in FIG. Think. The input image data of this color image is converted into black, cyan, magenta image data 30 to
When it is decomposed into 32, it becomes as shown in FIGS. Incidentally, in the case of the image shown in FIG. 29A, since there is no yellow image, the input image data 33 corresponding to yellow is all “0”.

Next, black, cyan, and magenta input image data 30 to 32 shown in FIGS.
Is subjected to image processing in a color image processing apparatus as follows. The input image data 31 of cyan of 8 pixels × 8 pixels is obtained by first setting a parameter 38 indicating the bit position (i, j) through a cyan filter 35 as shown in FIG. Of the image data to be printed is obtained. The output data 51 that has been filtered for cyan is
The signal is input to one of the AND circuits 40, and the AND circuit 40
And is taken between the black input image data 30 input to the other. The output data 52 of the AND circuit 40 is ORed with the cyan input image data 31 by the OR circuit 43 as shown in FIG. Is obtained. The cyan output image data 47 is the cyan output image data 4 shown in FIG.
Compared with No. 7, the area to be printed differs depending on the cyan ink dot in the black image area.

Further, the above-described cyan input image data 3
Similar to 1, the same image processing is performed on the magenta and yellow input image data 32 and 33. That is, the bit information (i, j) of the input image data is
Through magenta and yellow filters 36 and 37 as shown in FIG. 1 (B) or FIG. 32 (B), a portion of the black image data where magenta and yellow dots are to be printed is obtained. The output data 53 and 54 processed by the magenta and yellow filters 36 and 37 are input to one of the AND circuits 41 and 42, and the black input image input to the other of the AND circuits 41 and 42. The logical product is taken between the data 30. The output data 5 of these AND circuits 41 and 42
Reference numerals 5 and 56 denote input image data 32 and 3 of magenta and yellow as shown in FIG.
OR is generated by the OR circuits 44 and 45 with the output circuit 3 to obtain magenta and yellow output image data 48 and 49 as shown in FIG. 31 (E) or FIG. 32 (E). The magenta and yellow output image data 48 and 49 are the magenta and yellow output image data 48 and 4 shown in FIG.
As compared with No. 9, the area to be printed is different depending on the magenta and yellow ink dots in the black image area.

Further, each of the black input image data 30 shown in FIG. 29B is subjected to image processing in the color image processing apparatus as follows. In the black input image data 30 of 8 pixels × 8 pixels, the parameter 38 indicating the bit position (i, j) is changed through a black filter 34 as shown in FIG. A portion of the data to be printed with dots of another color is required. The output data 57 that has been subjected to the black filter processing is input to one of the AND circuits 39, and the logical product is obtained between the black input image data 30 input to the other of the AND circuits 39. This AN
The output data of the D circuit 39 is output as it is as black output image data 46, and black output image data 46 as shown in FIG. 33C is obtained. The black output image data 46 is exactly the same as the black output image data 46 shown in FIG.

In this way, image data 46 to 49 that have been subjected to predetermined image processing by the color image processing circuit are obtained. As shown in FIG.
c and 1d at predetermined timings, and a color image as shown in FIG. 34A is recorded on the recording paper 2 by ink dots.

By performing the above processing, the image to be printed with the black ink having the low permeability according to the conversion rule shown in FIG. 26 is combined with the black ink K having the low permeability as shown in FIG. Printing can be performed by superimposing ink C of a color such as cyan which has a high permeability, and the penetration speed of the ink in the black printing portion can be increased.
A color image processing method and apparatus capable of reducing bleeding of ink at the boundary between a black printed portion and a color printed portion and capable of recording an image free from mixed color bleeding between black and color. Can be provided. Further, since the black printing portion is not replaced with color ink at all, even if the black printing portion is a linear image having a small area, it can be clearly recorded in black. In FIG. 34B, ink with low permeability such as black is recorded first, and then ink with high permeability such as cyan is recorded. The same effect can be obtained even if the recording is performed on the ink, and then the ink having a low permeability is recorded.

In the above embodiment, the conversion rule shown in FIG. 13 is suitable for obtaining a clear and sharp image, and the conversion rule shown in FIG. 26 is suitable for obtaining an image having a high density. By selecting these two types of conversion rules according to the properties of the recording paper, it is possible to maintain higher quality image quality.

These processes operate when the color document mode is selected by the selection means for selecting a color document. The means for selecting a color document may be a switch that can be set by the user, or may be programmed to detect a header indicating a color document recorded in bitmap information or the like in the document and to automatically set it. good.

The output image data 46 to 49 of black, cyan, magenta, and yellow obtained by the above-described color image processing correspond to the corresponding colors of the recording head 1 of the ink jet recording apparatus as shown in FIG. Are applied at predetermined timing to the recording units 1a, 1b, 1c, and 1d, respectively, and are recorded on the recording paper 2. In the ink jet recording apparatus having such a configuration, the recording can be performed by the four recording heads in one scan by the width of the nozzle array of the recording head. At this time, depending on the arrangement order of each color of the recording head, in particular, the positional relationship between the recording head of the color using the ink having a low permeability and the recording head of another color and the scanning direction, the ink having the low permeability and the permeability may be different. The recording order of the fast inks is different.

In the ink jet recording apparatus shown in FIG. 1, it is assumed that, for example, black ink having low permeability is recorded by the recording section 1a, and recording is performed by scanning from left to right in the drawing. At this time, first, black ink having low permeability is recorded. However, because the permeability is slow, before the ink dries, the next fast permeability,
For example, cyan ink is recorded.

For example, when printing is performed using the pattern shown in FIG. 5 or printing is performed using the pattern shown in FIG. 22 (A), the black ink is printed first, and the cyan ink is used later. Recorded in between. At the time of cyan recording, the previously printed black ink has not been sufficiently permeated and dried, and liquid ink droplets are present on the recording paper. If, for example, cyan ink with a high permeability is recorded in this state,
As shown in FIG. 6 and FIG. 22 (B), the cyan ink combines with and mixes with the adjacent black ink, and the liquid black ink penetrates due to the fast permeability of the cyan ink.

Further, for example, printing is performed by using a pattern as shown in FIG. 10A or a pattern as shown in FIG. 34A in which ink having low permeability and ink having high permeability are overlapped. In this case, FIG. 10B and FIG.
As shown in (B), before the previously recorded ink with a low permeability does not sufficiently penetrate, the ink with a high permeability is recorded, and the two are mixed. At this time, the permeability of the mixed ink is high, and the ink having a low permeability quickly permeates the recording paper.

Of course, the color boundaries, for example, FIG. 5 and FIG.
Although it is conceivable that color mixing occurs every other dot for about one dot at the boundary between the region 22 and the region 23 shown in FIG.
As in the related art, there is no large color mixture in which the ink in the entire area printed with black ink flows into the adjacent color area.

Conversely, in the ink jet recording apparatus shown in FIG. 1, for example, the recording unit 1d performs recording of black ink having low permeability by scanning from left to right, or recording by scanning from right to left. When the recording of black ink with low permeability is performed by the unit 1a, first, ink with high permeability is recorded, and thereafter, ink with low permeability is recorded. For example, when printing is performed using the pattern shown in FIG. 5 or printing is performed using the pattern shown in FIG. 22A, cyan ink is printed first and black ink is printed between cyan inks. Is done. At the time of black recording, the cyan ink that has been previously recorded has almost penetrated the recording paper. The portion where the ink having high permeability such as cyan ink has permeated has improved liquid permeability compared to the portion where nothing is recorded. If a black ink having a low permeability is recorded in this state, the black ink droplet overlaps with the area of the cyan recording dot previously recorded in the peripheral portion of the black ink droplet, and the black permeability in this portion is improved. . Therefore, the black ink spreads in such a manner as to mix with the cyan dots, and the black ink rapidly permeates the recording paper from the area where the cyan dots were previously recorded. As a result, the black ink penetrates quickly, and does not largely flow into the recording areas of other colors, thereby preventing bleeding.

Further, for example, printing is performed by a pattern as shown in FIG. 10A or a pattern as shown in FIG. 34A in which ink having low permeability and ink having high permeability are overlapped. The same applies to the case where ink with a high permeability such as cyan is first recorded and penetrated, and then ink with a low permeability is superimposed and recorded. However, the color does not largely flow into the recording areas of other colors, and no bleeding occurs.

Of course, in this case as well, it is conceivable that mixed colors occur every other dot at the color boundary, for example, about one dot at the boundary between the regions 22 and 23 shown in FIG. 5 and FIG. As in the related art, there is no large color mixture in which the ink in the entire area printed with black ink flows into the adjacent color area.

In addition to the ink jet recording apparatus using four recording heads as shown in FIG. 1, the above recording method can be applied to a two-head ink jet recording apparatus. FIG. 35 is a schematic configuration diagram showing another embodiment of an inkjet recording apparatus to which the inkjet recording method according to the present invention can be applied, and FIG. 36 is an explanatory diagram of the configuration of a recording head. Reference numeral 81 denotes a recording head for recording ink having a low permeability, and can record black, for example. This recording head 81
For example, 128 nozzles are arranged in a line or in a zigzag pattern, and black ink is ejected from all the nozzles to perform printing.

Reference numeral 82 denotes a recording head for recording ink having high permeability, which can record, for example, three colors of cyan, magenta, and yellow. The recording head 82 also has, for example, 128 nozzles arranged in one row or in a staggered manner. Then, the ink is divided into three, and ink of each color is ejected to perform recording.
For example, it can be configured to perform printing using 40 nozzles for each color. Four nozzles between the nozzle rows of each color can be used as dummy nozzles that do not perform printing. This dummy nozzle can be set to 0, and the nozzles are not arranged for the dummy nozzles.
The recording head 82 can be configured to have a space. FIG. 36 shows an example in which printing is performed using each of the nozzle groups divided into three in the order of cyan, magenta, and yellow.

Reference numeral 83 denotes a carriage, and the recording head 81
And 82 are detachably fixed. Carriage 83
Are slidably attached to two guide rods 84. The carriage 83 has a timing belt 8.
5 is connected. The timing belt 85 is driven by a drive motor 86, and the carriage 83
Move left and right. With the movement of the carriage, ink is ejected from the recording heads 81 and 82, thereby performing recording in the main scanning direction. The recording paper is a platen roller 88
The recording paper is fed between the recording heads 81 and 82 such that the recording paper is fed by the rotation of a platen roller 88 by a paper feed motor 89, and sub-scanning is performed.
When recording is not performed or when maintenance of the recording head is performed, the recording heads 81 and 82 are moved to the position of the maintenance station 87 to perform capping and a predetermined maintenance operation.

In such a two-head ink jet recording apparatus, since the number of recording heads is small, an inexpensive recording apparatus can be constructed, and the apparatus can be downsized.

In the above-described two-head ink jet recording apparatus, when recording is performed only in black, recording is performed using all nozzles of the recording head 81. In a normal printing operation, printing is often performed only in black, such as a character image, and a certain high-speed printing speed is secured. When printing is performed using cyan, magenta, and yellow, or when printing is performed using these colors and black, all four colors cannot be printed in the same area at once. The printing is performed in units of a printing width equal to or less than the width of the nozzle group, such as the width of the divided nozzle group or half of the width.

Hereinafter, several examples of the recording operation in the case of recording the ink having the high permeability into the recording area of the black ink having the low permeability as described above using the two-head ink jet recording apparatus will be described. This will be described with reference to FIG. In the following description, as shown in FIG. 37, the yellow region 27, the black region 22, and the cyan region 2
3 will be described as an example. As shown in FIG. 37, the black region 22 is a pattern obtained by combining the black pattern of every other dot described in FIG. 5 with the pattern of overlapping the ink having high permeability and the ink having low permeability described in FIG. Is used. In the case of recording ink with high permeability, blue is recorded using both cyan and magenta from the viewpoint of color development. Note that, for the sake of simplicity, it is assumed that no dummy nozzle is provided between the nozzle groups of each color of the recording head 82. In FIGS. 38 to 51, cyan is represented by a circle.
Are shown by adding ＼, magenta is shown by adding ／ to /, yellow is shown by ○, and black is shown by ◎. When these inks are recorded in an overlapping manner, the respective symbols are shown in an overlapping manner. For example, when black and cyan are recorded in a superimposed manner, ＼ is shown with ＼. Furthermore, although there are usually several tens of nozzle groups for each color, only four nozzle groups are shown here for simplicity. Further, in these figures, the recording paper is fed from top to bottom in the figures, and the feeding width is the width of the nozzle group for recording each color of the recording head 82. The recording area on the recording paper corresponding to this feed width is called a band.

FIGS. 38 to 42 are explanatory diagrams of a first specific example of a recording operation using two heads. In this example, the recording head 81 and the recording head 82 do not perform recording at the same time in the same scan, but perform a recording operation alternately. First, as shown in FIG. 38, the first band A to be recorded is a cyan recording area of the recording head 82.
The recording paper is set. Then, cyan is recorded by the first scan. At this time, dots are recorded not only in the area 23 where cyan is to be recorded but also in an area where black is to be recorded. The next print scan is a scan for recording black, but black is not recorded in band A at this time.

When the two print scans are completed, the recording paper is fed one band downward from the top in the figure. This allows magenta to be recorded in band A and cyan to be recorded in band B, as shown in FIG. In this state, the print scan by the recording head 82 is performed. Then, recording in cyan is performed on band B, as in the case of FIG. At the same time, magenta recording is performed on band A. Magenta has the pattern shown in FIG.
There is no data to be recorded, but the black area 22
Magenta is recorded on the dot on which cyan is recorded. The dots recorded in an overlapping manner become blue.

In the next print scan, a recording operation of black by the recording head 81 is performed. At this time, of the nozzles provided in the recording head 81, only the nozzles corresponding to the nozzles used for recording magenta by the recording head 82 are used, and cyan and magenta are recorded in the black area 22. Black recording with a low penetrability is performed on the dots that are not present. The pattern recorded up to this print scan is a pattern as shown in FIG. That is, printing is performed by replacing some of the dots in the black printing area 22 with ink having high permeability. As described above, when black is recorded by this print scan, inks having high permeability, such as cyan and magenta, have already penetrated the recording paper, and the portion where these inks have penetrated has been recorded next. Improves permeability of black ink. In the figure, the dots are shown as being separated from each other, but they actually overlap little by little, and due to a slight landing error, etc., the black ink dots are already recorded in cyan and magenta. Dot overlaps with the dot. Therefore, although the black ink has low permeability, it penetrates quickly around the periphery, and consequently penetrates quickly.

Since the two print scans have been completed, the recording paper is fed by one band, and yellow can be recorded in band A, magenta in band B, and cyan in band C, as shown in FIG. By performing recording with the recording head 82 in this state, cyan dots are recorded in a part of the cyan recording region 23 and a part of the black recording region 22 in the band C, and the black region 22 is recorded in the band B. A magenta dot is recorded so as to overlap the cyan dot. Further, in band A, yellow dots are recorded in yellow area 27. At this time, in the black area 22, black dots having low permeability have already been recorded, but black ink has permeated the recording paper by the cyan and magenta dots recorded earlier, and yellow recording has been performed. Black does not enter the area 27. Even if bleeding occurs, it is about one dot bleed.

In the next print scan, black recording is performed by using the recording head 81. As shown in FIG. 42, black is recorded in the dots of the band B where the cyan and magenta are not recorded, in the black area 22. Is done. The operation in this area is as described in FIG. Further, in the black area 22 of the band A, black recording is performed so as to overlap the dots where cyan and magenta are recorded. That is, the pattern described with reference to FIG. As for the dots to be recorded, the dots having low permeability are superimposed on the dots having high permeability, contrary to FIG. 10B. By the time a black dot having a low permeability is recorded, cyan and magenta inks having a high permeability have already permeated the recording paper. The portion where the ink has penetrated promotes the penetration of the black ink having a low permeability, so that the black ink having a low permeability also penetrates quickly like the ink having a high permeability. for that reason,
There is no movement of ink to the adjacent area, and bleeding can be prevented.

(2) Since the print scan is completed, the recording paper is fed by a predetermined amount. Thereafter, the recording head 8 shown in FIG.
2, the recording operation of cyan, magenta, and yellow, the recording operation of black by the recording head 81 shown in FIG.

As described above, according to the recording operation as in the first specific example, the ink having the low permeability recorded in the black recording area is different from the ink using the adjacent ink having the high permeability. Penetration into the color recording area can be minimized, and a high-quality recording image free from bleeding and white spots in the black area can be obtained.

FIGS. 43 to 45 are explanatory diagrams of a second specific example of the recording operation using two heads. In this example, an example is shown in which printing is performed using both print heads 81 and 82 during one scan. First,
The recording paper is fed, and the recording paper is set such that the leading band A to be recorded is the cyan recording area of the recording head 82 as shown in FIG. Then, cyan is recorded by the first scan. At this time, dots are recorded not only in the area 23 where cyan is to be recorded but also in the area 22 where black is to be recorded. In this print scan, black is not recorded in band A. When the recording of cyan in band A is completed, the recording paper is fed by one band.

In the next print scan, magenta can be recorded in band A and cyan can be recorded in band B, as shown in FIG. In this state, print scan by the recording head 81 and the recording head 82 is performed. At this time, assuming that the scanning direction is from right to left in the figure, magenta is recorded first in band A, and then black is recorded. Magenta is recorded so as to be superimposed on the dot in the black recording area 22 where cyan was recorded in the previous print scan, that is, the print scan shown in FIG. The cyan ink having a high permeability has penetrated into the recording paper before the print scan is performed. And
The magenta ink, which is recorded over the cyan recorded dots, also has a high permeability, so that the permeation into the recording paper is started immediately upon landing on the recording paper. Black is recorded at a dot position in the recording area 22 where cyan and magenta are not recorded. At this time, the dots are recorded in such a size that the dots slightly overlap with each other, and there are some errors in the landing position.Therefore, the black dot is different from the adjacent cyan and magenta recorded dots in the periphery. Will be combined. The previously recorded magenta ink is in the middle of penetrating into the recording paper, and mixes with the black ink to promote the permeation of the black ink. Therefore, the black ink having low permeability penetrates quickly together with the magenta ink recorded on the adjacent dots. At this time, the cyan recording area 23
The black dots printed adjacent to are drawn to some extent by cyan printed dots, but are also drawn to adjacent cyan and magenta printed dots, minimizing color mixing. . In addition, in band B,
As in FIG. 43, only cyan recording is performed.

In the next print scan, as shown in FIG. 45, yellow and black are recorded in band A, magenta and black are recorded in band B, and cyan is recorded in band C. The recording operation for bands B and C is the same as the recording operation for bands A and B shown in FIG. For band A, first, recording is performed with yellow ink having high permeability in the yellow recording area 27, and then black recording is performed on the cyan recording area and magenta recording dot of the black recording area 22. Done. By the time of black recording, cyan,
Since the magenta recording is performed, the permeability of the black ink is accelerated, and the black ink penetrates the recording paper quickly despite its low permeability. At the boundary between the adjacent yellow recording areas 27, the penetration of the previously recorded yellow dots is not sufficient, so that some coupling with the later recorded black dots occurs. To penetrate the recording paper,
Color mixing is minimized.

In the subsequent print scan, the recording operation shown in FIG. 45 is repeatedly performed together with the sheet feeding operation. As described above, in the second specific example of the recording operation, black ink having low permeability and ink of another color having high permeability are recorded in the same print scan. In the past, black ink flowed out to the adjacent recording area of another color, causing large bleeding, white spots in the black recording area, and the like. In addition, color mixing was minimized, and high image quality was obtained.

FIGS. 46 to 48 are explanatory diagrams of a third specific example of the recording operation using two heads. Also in this example, recording is performed simultaneously using the recording heads 81 and 82 within one print scan. In the second specific example described above, a recording scan in which black recording is performed together with magenta,
The recording was performed in two scans of the recording scan performed together with yellow. In the third specific example, a case is shown in which black recording is performed in one scan together with yellow. First band A to be recorded as shown in FIG.
The recording paper is set such that is the cyan recording area of the recording head 82. Then, the cyan recording area 23
Then, cyan is recorded in a part of the black recording area 22. When the print scan is completed, the recording paper is fed by one band.

In the next print scan, magenta is recorded in band A and cyan is recorded in band B, as shown in FIG. The recording operation of band B is the same as the operation shown in FIG. Band A has a black recording area 2
2, a magenta dot is recorded so as to overlap the cyan dot already recorded. After the end of the print scan, a feeding operation for one band of recording paper is performed.

In the next print scan, as shown in FIG. 48, yellow and black are recorded in band A, magenta is recorded in band B, and cyan is recorded in band C. The recording operation for bands B and C is as shown in FIG. In the band A, yellow is first recorded in the recording area 27 by the recording head 82. Since the yellow ink has a high permeability, the penetration into the recording paper starts immediately. Subsequently, black is recorded in the recording area. Since the black ink has a low permeability, the dots are connected and the ink in the entire recording area is connected. In this state, the yellow dots recorded in the adjacent yellow recording area 27 have not sufficiently penetrated the recording paper. Conventionally, the ink connected over the entire recording area combines with the adjacent yellow ink, and flows largely into the yellow area to cause bleeding. However, in the present invention, the permeability of the cyan and magenta dots previously recorded in the black recording area is improved, and the black ink having a low permeability has the cyan and magenta recorded dots in advance. Will rapidly penetrate into the recording paper. In the portion adjacent to the yellow recording area 27, the black ink is slightly drawn by the yellow ink, but is also drawn by the penetrating portion inside, and does not penetrate into the yellow recording area as much as in the conventional case. Etc. can be minimized.

The subsequent print scan is the same as the operation shown in FIG. 48, and print scan and paper feed are repeated to record the entire recording paper.

FIGS. 49 to 51 are explanatory diagrams of a fourth specific example of the recording operation using two heads. In each of the above examples,
Black is recorded after cyan and magenta are recorded. This example shows an example in which black is first recorded, and then recording of another color is performed. First, as shown in FIG. 49, the recording paper is set such that the leading band A to be recorded is the cyan recording area of the recording head 82.
Then, black and cyan are recorded by the first print scan. At this time, area 2 where cyan is to be recorded
In addition to the portion 3, dots are also recorded in the area 22 where black is to be recorded. If the print scan direction is from left to right in the figure, black with low permeability is recorded first,
Subsequently, cyan having a high permeability is recorded. At the time when black having low permeability is recorded, black dots are combined with each other and exist on the recording paper without penetrating the recording paper, as in the related art. Shortly thereafter, cyan is recorded. Cyan is black recording area 2
2, the ink is mixed with the black ink existing on the recording paper without penetrating the recording paper. Then, the permeability of the mixed black and cyan inks to the recording paper is fast, and the black ink existing on the recording paper rapidly permeates the recording paper together with the cyan ink. In this print scan, recording is also performed on the cyan recording area 23 at the same time. However, since the permeability of the black ink is improved, a large amount of black ink flows into the cyan recording area and bleeds as in the related art. Will not cause. After this print scan,
The recording paper is sent for one scan.

In the next print scan, magenta is recorded in band A, and cyan and black areas are recorded in band B. Band B is as shown in FIG. The recording of magenta in band A is performed so as to overlap the cyan dots recorded in the black area during the previous print scan. Although this magenta recording does not directly affect the permeability of black ink, magenta is recorded together with cyan to prevent black from becoming a cyan-colored color and to further improve black coloring. ing. Then, the recording paper is fed by one scan, and as shown in FIG. 51, a print scan for recording yellow in band A, magenta in band B, and cyan and black in band C is performed.
In this print scan, bands B and C are as shown in FIG. In band A, yellow dots are recorded in a yellow recording area 27.
In the subsequent operations, the paper feeding and the print scan shown in FIG. 51 are repeatedly performed.

As shown in each of the above-described specific examples, by recording ink having high permeability in the black area using ink having low permeability, the ink having low permeability can penetrate into the recording paper. Can be promoted, and thereby, it is possible to prevent bleeding into a recording area of another adjacent color. At this time, irrespective of the recording order of the ink having a low permeability and the ink having a high permeability, the same effect could be obtained by performing either of them first.

As described above, by performing recording in a recording area of ink having a low permeability with ink having a high permeability, the permeability of the ink having a low permeability can be improved. The same effect can be obtained with the recording operation of the above. For example, in an example in which two print heads are operated by separate print scans as in the first specific example, black is first recorded, and then control is performed such that cyan and magenta are recorded in a black recording area. It is possible to control so as to perform black printing between cyan and magenta printing, or to perform black printing after yellow printing. Further, in the first specific example, it is also possible to record black two times as in the second specific example. The two black recording scans are performed by selecting two from before cyan recording, between cyan and magenta, between magenta and yellow, and after yellow recording, and recording black in the selected recording scan. do it.
In the first specific example, the recording by the recording head 82 is performed first and the recording by the recording head 81 is performed later in the same band. However, the reverse may be performed. Can be recorded.

In the second specific example, the same applies when the colors recorded together with black are cyan and yellow, and cyan and magenta. Further, in the third and fourth embodiments, the colors recorded with black are cyan,
The same is true regardless of whether magenta or yellow is selected. Furthermore, by changing the scanning direction, the printing order of the recording head 81 and the recording head 82 in the same printing scan can be changed.
Similar effects can be obtained.

In each of the specific examples described above, an example in which black is recorded on all the dots in the black area has been described. However, it is needless to say that, as shown in FIG. 5, FIG. 9, and FIG. Or a pattern in which black and other colors overlap and there are dots that are not recorded, as shown in FIG.

Further, in each of the above specific examples, cyan and magenta blue are recorded in the black recording area. However, it is needless to say that another color such as cyan alone may be used as shown in FIG. , FIG. 9, FIG. 22, and FIG.
The recording may be performed by using three colors to be superimposed on or adjacent to black.

[0147]

The present invention has the above-described structure and operation, and realizes recording of a high-density character image on plain paper such as copy paper without using special recording paper dedicated to ink-jet recording. It is possible to provide an ink jet recording method and an apparatus thereof capable of preventing occurrence of color blur between different color images, and a color image processing method and an apparatus therefor.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of an ink jet recording apparatus to which an ink jet recording method according to the present invention can be applied.

FIG. 2 is a chart showing ink compositions, physical properties and characteristics.

FIG. 3 is a table showing characteristics of recording paper.

FIG. 4 is a schematic diagram showing ink dots.

FIG. 5 is a schematic diagram showing a printing example.

FIG. 6 is a schematic diagram showing a printing example.

FIG. 7 is a schematic diagram showing a printing example.

FIGS. 8A to 8C are tables respectively showing the results of print evaluation.

FIG. 9 is a schematic diagram showing a printing example.

FIGS. 10A and 10B are schematic diagrams showing print examples, respectively.

FIG. 11 is a schematic diagram showing a printing example.

FIG. 12 is a schematic diagram showing a printing example.

FIGS. 13A to 13C are explanatory diagrams showing conversion rules of a color image processing method according to an embodiment of the present invention.

FIGS. 14A and 14B are explanatory diagrams respectively showing a conversion state of a print pattern of an ink dot in the embodiment.

FIGS. 15A to 15D are tables showing printing positions of inks of respective colors.

FIG. 16 is a block diagram showing one embodiment of a color image processing apparatus according to the present invention.

FIGS. 17 (a) to 17 (d) are charts respectively showing printing positions of inks of respective colors.

FIGS. 18A to 18E are tables showing the conversion states of the printing positions of cyan ink, respectively.

FIGS. 19A to 19E are tables respectively showing the conversion states of the printing positions of magenta ink.

FIGS. 20A to 20E are tables showing the conversion states of the printing positions of yellow ink, respectively.

FIGS. 21 (a) to 21 (c) are tables each showing a conversion state of a printing position of black ink.

FIGS. 22A and 22B are a diagram showing a printing state of ink dots of each color and a schematic diagram showing a printing state of ink dots of each color.

FIG. 23 is a block diagram showing another embodiment of the color image processing apparatus according to the present invention.

FIG. 24 is a flowchart showing the operation of the embodiment.

FIG. 25 is an explanatory diagram showing filter constants used for conversion.

FIGS. 26A to 26C are tables respectively showing conversion rules of another embodiment of the color image processing method according to the present invention.

FIGS. 27 (a) and 27 (b) are explanatory diagrams respectively showing a conversion state of a print pattern of an ink dot in the embodiment.

FIGS. 28A to 28D are tables showing printing positions of inks of respective colors.

FIGS. 29A to 29D are tables each showing a printing position of each color ink.

FIGS. 30A to 30E are tables respectively showing the conversion states of the printing positions of cyan ink.

FIGS. 31 (a) to (e) are tables showing conversion states of the printing positions of magenta ink, respectively.

FIGS. 32 (a) to 32 (e) are tables respectively showing the conversion states of the printing positions of yellow ink.

FIGS. 33 (a) to 33 (c) are tables respectively showing the conversion states of the printing positions of black ink.

FIGS. 34 (a) and (b) are a diagram showing a printing state of ink dots of each color and a schematic diagram showing a printing state of ink dots of each color.

FIG. 35 is a schematic configuration diagram showing another embodiment of an ink jet recording apparatus to which the ink jet recording method according to the present invention can be applied.

FIG. 36 is an explanatory diagram of a configuration of a recording head in another embodiment of the ink jet recording apparatus shown in FIG.

FIG. 37 is a schematic diagram showing a printing example.

FIG. 38 shows a first example of a recording operation using two heads.
FIG. 9 is an explanatory diagram of a first print scan of the specific example.

FIG. 39 is a first example of a recording operation using two heads.
FIG. 10 is an explanatory diagram of a third print scan of the specific example.

FIG. 40 is a first example of a recording operation using two heads.
FIG. 14 is an explanatory diagram of a fourth print scan of the specific example.

FIG. 41 is a first example of a recording operation using two heads.
FIG. 15 is an explanatory diagram of a fifth print scan in the specific example.

FIG. 42 shows a first example of a recording operation using two heads.
FIG. 14 is an explanatory diagram of a sixth print scan of the specific example.

FIG. 43 shows a second example of the recording operation using two heads.
FIG. 9 is an explanatory diagram of a first print scan of the specific example.

FIG. 44 shows a second example of the recording operation using two heads.
FIG. 11 is an explanatory diagram of a second print scan of the specific example.

FIG. 45 shows a second example of the recording operation using two heads.
FIG. 10 is an explanatory diagram of a third print scan of the specific example.

FIG. 46 shows a third example of the recording operation using two heads.
FIG. 9 is an explanatory diagram of a first print scan of the specific example.

FIG. 47 shows a third example of the recording operation using two heads.
FIG. 11 is an explanatory diagram of a second print scan of the specific example.

FIG. 48 shows a third example of the recording operation using two heads.
FIG. 10 is an explanatory diagram of a third print scan of the specific example.

FIG. 49 is a fourth example of the recording operation using two heads.
FIG. 9 is an explanatory diagram of a first print scan of the specific example.

FIG. 50 is a fourth example of the recording operation using two heads.
FIG. 11 is an explanatory diagram of a second print scan of the specific example.

FIG. 51 is a fourth example of the recording operation using two heads.
FIG. 10 is an explanatory diagram of a third print scan of the specific example.

FIG. 52 is a schematic diagram showing a printing example.

FIGS. 53 (a) and 53 (b) are schematic diagrams respectively showing the state of penetration of ink into a recording medium.

FIGS. 54 (a) and (b) are schematic views respectively showing the state of penetration of ink into a recording medium.

FIG. 55 is a schematic diagram showing a test apparatus for testing the state of penetration of ink into a recording medium.

FIG. 56 is a graph showing characteristics of a state of ink penetration into a recording medium.

[Explanation of symbols]

1 recording head, 1a, 1b, 1c, 1d recording section, 2
Recording sheet.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-60-106270 (JP, A) JP-A-4-110158 (JP, A) JP-A-3-234679 (JP, A) JP-A-60-106 253550 (JP, A) JP-A-6-135012 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B41J 2/21

Claims (16)

(57) [Claims] In an ink jet recording method for recording a color image using a black ink having low permeability and a color ink having high permeability, some of the pixels to be printed in black are: The pixels to be printed with black ink dots using black ink and adjacent to some of the pixels to be printed with black are replaced with black ink and color ink using any one of color inks. An ink jet recording method characterized by printing with dots. 2. A color ink dot used for printing one color at a time for printing a pixel adjacent to the partial pixel to be printed in black, wherein all color ink dots are used. 2. The ink jet recording method according to 1. 3. In an ink-jet recording method for recording a color image using black ink having low permeability and color ink having high permeability, some of the pixels to be printed in black are: The pixels to be printed with black ink dots using black ink and adjacent to some of the pixels to be printed in black are replaced with black ink and color ink using any two colors of color ink. An ink jet recording method characterized by printing by overlapping dots. 4. In an ink-jet recording method for recording a color image using black ink having low permeability and color ink having high permeability, some of the pixels to be printed in black are: The ink dots using the black ink and the color ink dots using any one of the color inks are printed in a superimposed manner, and the pixels to be printed in black adjacent to some of the pixels are printed. An ink jet recording method characterized by using empty dots that are not used. 5. In an ink jet recording method for recording a color image using black ink having low permeability and color ink having high permeability, some of the pixels to be printed in black are: The ink dots using the black ink and the color ink dots using any two of the color inks are superimposed and printed. Pixels to be printed in black adjacent to some of the pixels are printed. An ink jet recording method characterized by using empty dots that are not used. 6. The ink jet recording method according to claim 1, wherein the brightness of the black ink having low permeability is lower than the brightness of the color ink having high permeability. . 7. The black ink having low permeability has an absorption coefficient (Ka) of 0.5 ml / m ² · ms ^1/2 or less, a wetting time (Tw) of 50 to 200 msec, and the high permeability. The absorption coefficient (Ka) of the color ink is 1.0 ml /
m ² · ms ^1/2 or more, wet time (Tw) is ²⁰ msec
7. The method according to claim 1, wherein:
Item 6. The ink jet recording method according to item 1. 8. A color image processing method for processing a color image when recording a color image using a black ink having a low permeability and a color ink having a high permeability. Some of the pixels to be printed are printed with ink dots using black ink, and the pixels to be printed in black adjacent to some of the pixels are printed in color instead of black. A color image processing method comprising: converting black image data so as to print with color ink dots using any one of the inks. 9. A color image processing method for processing a color image when recording a color image using a black ink having a low permeability and a color ink having a high permeability. Some of the pixels to be printed are printed with ink dots using black ink, and the pixels to be printed in black adjacent to some of the pixels are printed in color instead of black. A color image processing method, comprising: converting black image data so that color ink dots using any two colors of ink are printed in a superimposed manner. 10. A color image processing method for processing a color image when recording a color image using a black ink having a low permeability and a color ink having a high permeability. Some of the pixels should be printed by superimposing an ink dot using black ink and a color ink dot using any one of the color inks on each of the pixels. Pixels to be printed in adjacent black should be empty dots that are not printed,
A color image processing method comprising converting black image data. 11. A color image processing method for processing a color image when recording a color image using a black ink having a low permeability and a color ink having a high permeability. Some of the pixels should be printed by superimposing an ink dot using black ink and a color ink dot using any two colors of color ink on each of the pixels. Pixels to be printed in adjacent black should be empty dots that are not printed,
A color image processing method comprising converting black image data. 12. A color image processing apparatus for processing a color image when recording a color image using black ink having a low permeability and color ink having a high permeability. Some of the pixels to be printed are printed with ink dots using black ink, and the pixels to be printed in black adjacent to some of the pixels are printed in color instead of black. A color image processing apparatus comprising: image data conversion means for converting black image data so that printing is performed by using color ink dots using any one of the inks. 13. A color image processing apparatus for processing a color image when recording a color image using black ink having low permeability and color ink having high permeability, wherein the color image is printed in black. Some of the pixels to be printed are printed with ink dots using black ink, and the pixels to be printed in black adjacent to some of the pixels are printed in color instead of black. A color image processing apparatus comprising image data conversion means for converting black image data so that color ink dots using any two colors of ink are superimposed and printed. 14. A color image processing apparatus for processing a color image when recording a color image using black ink having low permeability and color ink having high permeability, wherein the color image processing apparatus prints black. Some of the pixels should be printed by superimposing an ink dot using black ink and a color ink dot using any one of the color inks on each of the pixels. Pixels to be printed in adjacent black should be empty dots that are not printed,
A color image processing apparatus comprising image data conversion means for converting black image data. 15. A color image processing apparatus for processing a color image when recording a color image using black ink having a low permeability and color ink having a high permeability, wherein the black image is printed. Some of the pixels should be printed by superimposing an ink dot using black ink and a color ink dot using any two colors of color ink on each of the pixels. Pixels to be printed in adjacent black should be empty dots that are not printed,
A color image processing apparatus comprising image data conversion means for converting black image data. 16. An ink jet recording apparatus, comprising: a control unit for performing printing in accordance with the image data converted by the color image processing apparatus according to claim 12. Description: