JPH11240184A - Method and apparatus for ink-jet recording - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and an apparatus for ink-jet recording whereby a medium to be recorded is less stained even after continuous recording at high speed and image quality deterioration is restricted to a minimum. SOLUTION: An outline of a pixel range to be recorded with ink of low permeability among input image information to be recorded is extracted by an outline extraction part 1. A part other than an outline part of one to several pixel widths including the extracted outline is subjected to conversion at a predetermined rate at a pixel conversion part 2, i.e., replaced with pixels to be recorded with ink of high permeability. In accordance with the image information to be recorded after converted at the pixel conversion part 2, images are recorded by a recording part 3 on a medium to be recorded with the use of inks of low permeability and high permeability. The recording of the images is controlled so that the ink of high permeability of at least one kind is first recorded, and the ink of low permeability is recorded later.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink-jet recording method and an ink-jet recording apparatus for performing recording for each pixel using at least a low-permeability ink and a high-permeability ink.

[0002]

2. Description of the Related Art An ink jet recording apparatus uses a discharge energy generator composed of a piezoelectric element, an electrothermal conversion element, or the like as a discharge drive source, discharges ink droplets from nozzles to fly, adheres to a recording medium, and performs recording. Do. This ink jet recording apparatus has low noise, does not require a special fixing device unlike a xerographic recording apparatus, and has a simple apparatus configuration, and thus can be downsized. In addition to being able to record black-and-white and full-color images, ink is absorbed and absorbed not only on so-called plain paper typified by special recording paper and copy paper, but also on a recording medium such as a film or cloth, and black and white or It has the feature that a color image can be recorded.

In recent ink-jet recording apparatuses, there is a tendency to use ink having high permeability in order to realize high-speed recording. However, for example, in the case of black ink or the like, since ink having high permeability lacks color development, recording is often performed using black ink having low permeability. When recording is performed using such low-permeability ink, bleeding and feathering of an outline portion are reduced, and characters and line drawings can be recorded with good image quality even on plain paper. To get the image,
In many cases, recording is performed using black ink that absorbs slowly.

However, when recording is performed using such low-permeability ink, the absorption of the ink into the recording medium becomes slow. Before the recording medium dries, the next recording medium is ejected, the recording surface is rubbed, and ink adheres to the back surface of the ejected recording medium, thereby causing stains.

In order to avoid such contamination of the recording medium, for example, there is an ink jet recording method in which after recording on the medium is completed, a waiting time necessary for the ink to dry is provided. However, there is a problem that the required time of the entire print job becomes longer due to the waiting time, and the print speed decreases.

[0006] As another avoiding method, for example, Japanese Unexamined Patent Publication No.
In Japanese Patent Application Laid-Open Nos. 5-69464 and 55-84670, a platen is heated by a heater incorporated in the platen, and the recording medium after recording is heated by contact heat transfer to adhere to the recording medium. A technique for accelerating the drying of the prepared ink is disclosed. However, in this method, it is necessary to provide a heating unit such as a heater for heating the recording medium inside the recording apparatus, which increases costs, increases energy consumption,
New problems arise, such as an increase in the size of the device, treatment of the generated heat, and the danger of fire.

Further, Japanese Patent Application Laid-Open No. 54-15637 discloses a technique for promoting drying of ink recorded by using hot air. Further, Japanese Patent Application Laid-Open No. Sho 57-12047
Japanese Patent Application Laid-Open Publication No. H11-133873 discloses a technique in which drying of recorded ink is promoted by heating a recording medium after recording using radiant heat of a heat source lamp. All of these ink drying means by heating are effective means for avoiding the above-described problem of medium contamination. However, in such an ink drying technique by heating, if the heating amount is the same regardless of the printing speed, the effect of drying the ink decreases as the printing speed increases. Therefore, in order to obtain an effective drying effect, it is necessary to increase the heating amount as the recording speed increases, and there is a disadvantage that the energy consumption is further increased.

Further, in order to improve the drying property of the ink particularly in the painted part, a method of reducing the ink amount by thinning out the pixels to be recorded in the painted part has been considered. For example, JP-A-8-336
In Japanese Patent Application Laid-Open No. 961, the outline of a painted portion is recorded without thinning to reproduce a smooth edge with little unevenness, and the inside is thinned to reduce the amount of ink by thinning out pixels to be recorded, thereby preventing poor drying. I have. But,
This does not mean that the ink having a low permeability has a high drying speed, and cannot improve the recording speed.

Japanese Patent Application Laid-Open No. 7-149036 describes a method of replacing a part of pixels to be recorded with ink having low permeability with ink having high permeability or recording with ink having high permeability. I have. According to this method, the ink having low permeability is enhanced in permeability by the ink having high permeability, and the penetration of the ink having low permeability into the recording medium is promoted, so that drying can be accelerated. Therefore, even when high-speed continuous recording is performed, stains on the recording medium can be reduced. However, since the contour portion is also composed of pixels with only low-permeability ink and pixels with high-permeability ink or pixels on which high-permeability ink and low-permeability ink are overlapped, the image quality of the contour portion is high. However, there is a problem in that the metal is deteriorated.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has problems such as increased costs, increased energy consumption, increased size of equipment, treatment of generated heat, and the danger of fire. It is another object of the present invention to provide an ink jet recording method and an ink jet recording apparatus in which a recording medium is less contaminated even when high-speed continuous recording is performed and image quality deterioration is minimized.

[0011]

According to the present invention, a portion other than a contour portion in a pixel region to be formed by ink having low permeability is recorded by using ink having high permeability at a predetermined ratio. It is recorded by replacing with pixels. Alternatively, pixels to be printed are thinned out with a low-permeability ink at a predetermined ratio, and pixels to be printed using a high-permeability ink in an amount approximately equal to the thinned-out ink are added for printing. The low-permeability ink rapidly penetrates into the recording medium together with the high-permeability ink, and is fixed as if it had high permeability. Accordingly, the ink having low permeability does not remain undried on the recording medium, and even when high-speed continuous recording is performed, it is possible to avoid contamination of the recording medium.

Generally, ink having high permeability penetrates not only in the depth direction of the medium but also in the lateral direction. Therefore, when recording is performed using only ink having high permeability, there is a problem that the outline of an image is blurred. is there. In the present invention, in the pixel area to be constituted by the low-permeability ink, the outline portion is recorded using the low-permeability ink as it is without using the high-permeability ink. Can be prevented, and a high-quality image in which the sharpness of the contour is maintained can be recorded.

[0013]

FIG. 1 is a block diagram showing an embodiment of an ink jet recording apparatus according to the present invention. In the figure, 1 is a contour extraction unit, 2 is a pixel conversion unit, and 3 is a recording unit. The contour extraction unit 1 extracts a contour of a pixel area to be printed with low-penetrability ink from input information of an image to be printed. The pixel conversion unit 2 includes, in a pixel region to be printed with ink having low permeability,
In addition, a conversion process is performed in which a portion other than the outline portion having a width of several pixels is replaced with a pixel recorded with a highly permeable ink at a predetermined ratio. Alternatively, a conversion process is performed in which pixels to be printed with ink having low permeability are thinned out at a predetermined ratio and pixels to be printed using ink having high permeability are added in an amount substantially equal to the thinned amount. The recording unit 3 records an image on a recording medium using low-permeability ink and high-permeability ink in accordance with the information of the image to be recorded that has been subjected to the conversion processing in the pixel conversion unit 2. At the time of recording an image, it is controlled so that at least one kind of ink having high permeability is recorded first and the ink having low permeability is recorded later when viewed in pixel units.

FIG. 2 is a perspective view showing an example of the configuration of a recording section in an embodiment of the ink jet recording apparatus of the present invention, and FIG. 3 is a front view of the same. In the figure, 11a-11
d is a recording head, 12a to 12d are ink tanks, 13
Is a signal cable, 14 is a carriage, 15 is a guide rod, 16 is a carriage guide, 17 is a timing belt, 18 is a drive motor, 19 is a drive pulley, and 20 is a recording sheet. Here, a configuration is shown in which color recording can be performed using four color inks of cyan (c), black (k), magenta (m), and yellow (y). Among them, black ink is frequently used, for example, for recording characters, and its coloring property tends to be regarded as important. Therefore, in the following description, a low-permeability ink having good coloring properties is used for this black ink, and a high-permeability ink is used for the other color inks.

As an example, an ink having low permeability (eg, black ink) has a surface tension of 4 here.
0mN / m to 60mN / m
Highly permeable inks (for example, cyan ink, magenta ink, and yellow ink) have a surface tension of 30 mN / m.
In this case, the ink has a value of less than about 40 mN / m.

Recording heads 11a, 11b, 11c, 11
d denotes four recording heads corresponding to four colors of cyan, magenta, black, and yellow, respectively. These recording heads 11a, 11b, 11c, and 11d form cyan, magenta, and cyan from nozzles provided on the lower end surface of the recording head.
Black and yellow inks are ejected according to the information of the image to be recorded. Thus, an image can be recorded on the recording paper 20 as a recording medium. The arrangement order of the recording heads of the respective colors is such that recording with high permeability ink is performed before black ink with low permeability even if the carriage 14 moves in any direction so that bidirectional recording can be supported. It is arranged in. If this condition is satisfied, the arrangement order of the recording heads of each color is arbitrary. When performing only one-way recording, an arbitrary arrangement order may be used as long as the black head does not become the head in the traveling direction.

The nozzle is a head carriage 14 to be described later.
Are arranged in a direction substantially perpendicular to the main scanning direction. As a specific example, 480 nozzles can be arranged in a row at a density of 400 nozzles per inch. The number and density of the nozzles are arbitrary, and the arrangement is also arbitrary such as, for example, a staggered arrangement.

The recording heads 11a, 11b, 11
c, 11d, cyan, magenta, black,
Ink tank 12 containing ink of each color of yellow
a, 12b, 12c, and 12d are integrally attached to the respective recording heads. Ink tanks 12a, 1
The inks contained in the recording heads 2b, 12c, and 12d correspond to the recording heads 11a, 11b, 11c, and 11 respectively.
d.

Further, each of these recording heads 11a, 1
A signal cable 13 is connected to 1b, 11c and 11d. The signal cable 13 uses the information of the image to be recorded after the conversion processing of each color of cyan, magenta, black, and yellow by the pixel conversion unit 2 as a head drive signal, and the recording heads 11a, 11b, 11c, 11
to d. For example, multi-valued color image data is binarized, developed into a dot pattern, processed by the contour extraction unit 1 and the pixel conversion unit 2 shown in FIG. 1, and transmitted to the recording head via the signal cable 13.

The recording heads 11a, 11b, 11c, 11
d is fixed to the head carriage 14. The head carriage 14 is slidably mounted in the main scanning direction (the direction of the double arrow in the drawing) along the guide rod 15 and the carriage guide 16. The head carriage 14 is connected to an end of a timing belt 17.
It is wound around a drive pulley 19 that is driven to rotate by the motor 8. By rotating the drive motor 18 at a predetermined timing, the head carriage 14 can be moved along the main scanning direction via the timing belt 17.

Although not shown, a platen is fixed below the head carriage 14, and a recording paper 20 is placed on the platen at a predetermined timing by a paper feed transport roller (not shown) at a predetermined timing. Is transported along the direction of the arrow. The platen can be made of, for example, a plastic molding material.

In recording, the drive motor 18 is driven to move the head carriage 14 via the timing belt 17 in the main scanning direction. Recording head 11
Since a, 11b, 11c, and 11d are fixed to the head carriage 14, the recording heads 11a, 11b, 11c, and 11d also move along the main scanning direction as the head carriage 14 moves. During the movement in the main scanning direction, the recording heads 11a, 11b, 11c, 1
1d is driven in accordance with a head drive signal sent via the signal cable 13 to eject ink of each color.
As a result, an image is recorded on the recording paper 20 by the four recording heads in a band-shaped area having a width equal to the arrangement width of the nozzles.

When one main scan is completed, the recording paper 20 is fed by a paper feed transport roller (not shown) as necessary. During this time, the carriage 14 is moved in the main scanning direction as needed, and preparations for the next main scanning are made. For example, when performing one-way recording, the recording heads 11a, 11b,
11c and 11d are returned to a predetermined end of the recording paper 20 (either the left end or the right end). Printing is performed while the carriage 14 is always moved in the same direction. When performing bidirectional recording, the recording head is moved to the end of the image to be recorded on the side closer to the current position of the recording head in accordance with the information of the image in the band area to be recorded next. Alternatively, the recording head may be stopped at the current position of the recording head. Then, the carriage 1
4 while moving in the direction of the side where the image to be recorded exists.

Next, a process of actually converting an image in one embodiment of the present invention will be described using a specific example. Note that, as described above, cyan, magenta, and yellow color inks are used as inks having high permeability, and black ink is used as ink having low permeability.

FIG. 4 is an explanatory diagram of an example of a contour extracting method in the contour extracting unit. Black circles in the figure indicate pixels to be printed with black ink. In the contour extraction unit 1,
For example, an outline of an image to be printed with black ink is detected using an outline detection window as shown in FIG. The central portion in the contour detection window, that is, the fifth pixel hatched in FIG. If the target pixel is not a pixel to be printed with black ink, for example, as shown in FIG. 4B, the target pixel is not a contour. Also, even if the target pixel is a pixel to be recorded with black ink,
If there are pixels in all of the contour detection windows, that is, if there are pixels to be printed with black ink in all of the positions 1 to 5, the target pixel is not a contour. For example, in FIG. 4C, since pixels exist in all of the outline detection windows, it is determined that the target pixel is not an outline part.

On the other hand, if the pixel of interest is a pixel to be printed with black ink and at least one of the surrounding positions 1 to 4 is not a pixel to be printed with black ink, the pixel of interest is a contour. . For example, in FIG. 4D, since there is no pixel to be printed with black ink at the second position in the contour detection window, the pixel of interest is determined to be a contour. In FIG. 4E, since there is no pixel to be printed with black ink at the first and second positions in the contour detection window, the target pixel is determined to be a contour.

FIGS. 5 and 6 are explanatory diagrams of another example of the contour detection window. Figure 4 shows the outline detection window.
Windows of various shapes other than those shown in FIG. For example, a 3 × 3 window as shown in FIG. 5A may be used. In this case, FIG.
If there is a pixel area (hatched area) to be printed with triangular black ink as shown in FIG. 5B, using the contour detection window shown in FIG. Pixels indicated by hatching are detected as contours. When the same image shown in FIG. 5B is subjected to the contour extraction processing using the contour detection window shown in FIG. 4A, the pixels shown by hatching in FIG. Is detected. The result of detecting the contours with oblique lines is different between the contour extraction result shown in FIG. 5C and the contour extraction result shown in FIG. 5D.

Alternatively, a larger size contour detection window as shown in FIG. 6, for example, can be used. In the contour detection windows shown in FIGS. 4A and 5A, one pixel around a pixel area to be printed with black ink can be detected as a contour. , (B), two surrounding pixels can be detected as a contour.

As described above, since the detection result of the contour differs depending on the shape and size of the window, environmental conditions, image quality,
The optimum shape and size of the contour detection window may be selected according to the amount of ink and other conditions.

FIG. 7 is an explanatory diagram of an example of contour extraction from a color image. In the figure, each rectangle indicates each pixel, the right half indicates the area of a pixel to be printed with black ink, and the left half indicates the area of a pixel to be printed with color ink. In the above description, an example of a method of detecting an outline based on the presence or absence of a pixel to be printed with black ink has been described. However, even when a black image and a color image are adjacent to each other, the above-described outline detection is performed. The contour can be detected using the window. Here, an example is shown in which the contour detection window shown in FIG. 4A is used, and the contour detection window is surrounded by a thick frame.

In a color image, there are many cases in which a pixel to be printed with another color ink exists adjacent to a pixel to be printed with black ink as in the example shown in FIG. In such a case, here, the pixels to be printed are considered as including the pixels to be printed with the color ink, and the contour of the pixel area printed with any of the inks is detected. In this case, since all pixels recorded by any of the inks are included in the contour detection window shown in FIG. 7, it is determined that the target pixel is not a contour. Therefore, it is determined that the boundary ab where the color image and the black image are adjacent is not an outline. The outline detected in the area of the pixel printed with black ink by this method is a pixel that can show a sharp outline by the pixel printed with black ink. To prevent.

Next, the pixel conversion section 2 performs a pixel conversion process. Here, a case will be described in which an image is created in which some of the pixels to be printed with black ink are replaced by pixels to be printed with color ink. 8 to 11
FIG. 4 is an explanatory diagram of an example of a specific operation of the pixel conversion unit according to the embodiment of the present invention. 8 to 11 show black ink, cyan ink, magenta ink,
4 shows a process of creating an image to be recorded with yellow ink. Here, as an example, 8 × as shown in FIG.
The conversion process of a pixel area to be printed with eight pixels of black ink will be described.

First, pixels to be converted from pixels to be printed in black to pixels to be printed in color ink are thinned out. Here, as an example, thinning is performed according to a conversion rule as shown in FIG. That is, for the upper 4 × 8 pixel region and the lower 4 × 8 pixel region of the image shown in FIG.
The logical product with the 4 × 8 pixel template shown in FIG. 8B is calculated. Then, the image is converted into an image shown in FIG.

Next, an image is created for embedding the pixels to be recorded with the color ink in the pixels thinned out from the pixel area to be recorded with the black ink. For example, FIG.
(B), the logical product of the upper half and the lower half of the 8 × 8 pixel image shown in FIG. 8A is calculated using the 4 × 8 pixel template shown in FIG. 11B. Note that FIG.
8 (A), FIG. 10 (A), and FIG. 11 (A) show the pixel area to be printed with the same black ink as the image shown in FIG. 8 (A). By this logical operation, an image composed of pixels to be printed with cyan ink, magenta ink, and yellow ink as shown in FIGS. 9C, 10C, and 11C is created.

In this way, a part of the pixels recorded with black ink can be replaced with the pixels recorded with color ink. In this example, about 30% of the image to be printed with black ink is replaced with pixels to be printed with color ink, and the remaining 70% is left as pixels to be printed with black ink. Also, at the time of replacement, 10% is applied to a pixel to be printed with cyan ink, 10% to a pixel to be printed with magenta ink, and 1% to a pixel to be printed with yellow ink.
0% has been replaced. 8 (C), 9 (C), 10
(C), in the image after replacement shown in FIG. 11 (C), there are no pixels recorded with a plurality of inks in 8 × 8 pixels, and no pixels recorded with any ink.

FIGS. 8 (C), 9 (C), 10 (C),
In the image shown in FIG. 11C, pixel replacement occurs even in the outline portion. Therefore, an output image is created so that the outline portion is recorded with black ink without replacement. First, an image composed of pixels to be recorded with black ink is a thinned image shown in FIG. 8C and an image shown in FIG. 8D composed of pixels determined to be contours by the contour extracting unit 1. Calculate the logical sum of As a result, all pixels in the outline portion are to be recorded with black ink, and an output image shown in FIG. 8E is obtained.

On the other hand, the image composed of the pixels recorded with the color ink is composed of the image composed of the replaced pixels shown in FIGS. 9 (C), 10 (C) and 11 (C). The logical product of the inverted image (FIG. 9 (D), FIG. 10 (D), FIG. 11 (D)) of the image composed of the pixels determined to be the contour is calculated. As a result, there are no pixels to be recorded with the color ink in the outline portion, and FIG. 9 (E) and FIG.
(E) and the output image shown in FIG. 11 (E) are obtained. 8 (F), FIG. 9 (F), FIG. 10 (F), FIG.
FIGS. 8 (E), 9 (E), and 10 (F) show FIGS.
(E), the output image shown in FIG. 11 (E) is shown as 1 or 0 data, and each row is shown as hexadecimal data.

FIG. 12 is a diagram illustrating an example of a specific operation of the recording unit according to the embodiment of the present invention. The output images shown in FIGS. 8 (E), 9 (E), 10 (E), and 11 (E) are shown in FIGS. 12 (A) to 12 (D).
Such an output image is supplied to, for example, the recording heads 11a to 11d shown in FIGS. As a result, the recording heads 11a to 11d record the images of the patterns shown in FIGS. At this time, since each output image is recorded while being aligned, the images shown in FIGS. 12A to 12D overlap, and an image as shown in FIG. 12E is obtained.

FIG. 13 is an explanatory diagram of an example of a printing order by each ink, and FIG. 14 is an explanatory diagram of an example of a process of penetrating ink into recording paper. In the configuration shown in FIGS. 2 and 3, when recording is performed by moving the carriage 14, when recording is performed from right to left in the drawing and when recording is performed from left to right, recording of ink of each color is performed. The order is different. First, as shown in FIG. 13, a case is considered in which printing is performed while moving the carriage 14 with the print head 11a that performs printing using cyan ink at the head. In this case, the order of recording at the same position on the recording paper 20 is cyan, magenta, black, and yellow. That is, with respect to a certain column of the output image shown in FIGS. 12A to 12D, FIG. 12B, FIG.
(A), and are recorded in the order of FIG.

In the pixel area to be printed with black ink, the pixels are replaced as described above, so that printing with color ink is also performed. FIG. 14 (A)
As shown in (1), cyan or magenta ink having high permeability lands on the recording paper 20 first. The landed cyan ink or magenta ink has a high penetrability, and immediately penetrates into the recording paper 20.

Thereafter, black ink having low permeability is ejected from the recording head 11c (FIG. 14).
(B)). At this point, the cyan and magenta inks that have already been recorded have almost penetrated the recording medium. The liquid penetrability is improved in a portion where the highly permeable ink such as cyan ink or magenta ink has penetrated and in the vicinity thereof, as compared with a portion where nothing is recorded. In this state, the droplets of the black ink land on the recording paper 20. Since the droplets are ejected in such an amount that the droplets are overlapped with each other, as shown in FIG. 14C, the peripheral portion of the landed black ink is formed of the cyan ink or the magenta ink previously recorded. Overlap with the infiltrated area. As a result, the black ink that has landed at a position adjacent to the area where the cyan ink or magenta ink has permeated is pulled by the part where the liquid permeability is improved by the permeation of the cyan ink or magenta ink,
This will quickly penetrate into the recording paper 20.

Thereafter, when yellow ink having high permeability is ejected (FIG. 14D) and lands on an adjacent pixel position, the recording area partially overlaps with the recording area of the previously arriving black ink. At this point, a part of the black ink may still remain on the recording paper 20 as a liquid. In such a case, the yellow ink that has landed later and the remaining black ink are mixed, and as a result, the black ink has the same permeability as the highly permeable yellow ink, and is more permeable than the black ink alone. It will penetrate quickly. Of course, the yellow ink also rapidly penetrates into the recording paper 20 due to its high permeability. As a result, each ink rapidly penetrates into the recording paper 20, the undried ink does not remain on the surface of the recording paper 20 forever, and it is possible to avoid medium contamination due to the undried ink even during continuous recording.

Also, when cyan ink or magenta ink has landed on both sides of the black ink landing position first as shown in FIG. 14 (F), as shown in FIG. The penetration of the ink is promoted by the cyan ink or the magenta ink on both sides, and the ink quickly penetrates the recording paper 20.

In the contour portion, although there is a possibility that the cyan ink or the magenta ink lands inside the contour portion, the ink does not land outside the contour portion. for that reason,
As shown in FIG. 14H, the black ink is penetrated by the inner cyan ink or the magenta ink, but the outer edge portion does not cause bleeding due to the ink penetration, and a sharp edge image is obtained. be able to. In addition, since a highly permeable ink is not used for the contour, an image having a sharp contour can be recorded.

FIG. 15 is an explanatory diagram of another example of the printing order by each ink. It is assumed that printing is performed when the carriage 14 moves in a direction opposite to the above-described direction. For example, as shown in FIG.
If the recording is performed while moving, the order of recording at the same pixel position is yellow, black, cyan, and magenta. That is, contrary to the above-described case, yellow ink with high permeability is printed, black ink with low permeability is printed, and then magenta and cyan ink with high permeability are printed in that order.

Even in this case, yellow ink having high permeability is recorded before recording of black ink having low permeability. The previously recorded yellow ink substantially penetrates into the recording paper 20 before the black ink recording, thereby improving the wettability of the recording paper 20. Therefore, when the black ink lands adjacent to the recording area of the yellow ink, the recording area partially overlaps with the portion where the wettability is improved by the yellow ink, and the black ink is pulled by the portion where the yellow ink has penetrated. This will quickly penetrate into the recording paper 20. However, the number of pixels of highly permeable ink recorded before black ink recording is performed in the scanning direction (right to left) shown in FIG.
The number is smaller than that in the case where scanning is performed for recording. Therefore, the effect of promoting the penetration by improving the wettability with the ink having high permeability is smaller than that in the case where the recording is performed in the scanning direction shown in FIG.

However, after recording with the black ink, the highly permeable cyan ink or magenta ink lands on adjacent pixel positions, so that these inks and the black ink remaining on the recording paper 20 are separated. When mixed, the black ink has the same permeability as the highly permeable cyan ink and magenta ink, and penetrates more quickly than the black ink alone. Therefore, as in the case where printing is performed in the scanning direction shown in FIG. 13, undried ink does not remain on the surface of the recording paper 20 indefinitely, and medium contamination due to undried ink is avoided even during continuous printing. can do. Of course, irrespective of such a scanning direction, as shown in FIG. 14 (H), since the outline is recorded only with the black ink having low permeability, bleeding peculiar to the ink having high permeability is suppressed. Thus, an image having a sharp outline can be obtained.

Several modified examples will be described. In the above-described example, when a part of the pixels to be printed with the black ink is replaced by the pixels to be printed with the color ink in the pixel conversion unit 2, for example, FIG. 8 (B), FIG. 9 (B), FIG.
Pixel replacement was performed using the template (conversion rule) shown in FIG. The size of the template and the pattern indicating the pixels to be replaced may be arbitrarily set, and may be set according to the replacement ratio.

Instead of using such a template, the template may be replaced with a random number or a pseudo-random number, for example. FIG. 16 is an explanatory diagram of another example of the pixel replacement process in the pixel conversion unit according to the embodiment of the present invention. FIG.
6 (A) shows pixels to be recorded with ink having high permeability,
FIG. 16B shows an ink having low permeability (black ink).
Indicates a pixel to be recorded. In addition, the outline is shown with hatching. The outline of the image area composed of pixels to be recorded with black ink is recorded with black ink. Pixels to be printed with black ink other than the outline, ie, inside the outline, are replaced with pixels that are printed with ink having high permeability by a predetermined ratio in a random or pseudo-random manner. The replaced pixels are thinned out from the pixels printed with the black ink shown in FIG. 16B, and the pixel data is generated as much as the pixels printed with the highly permeable ink shown in FIG. 16A. Pixels to be recorded with the ink having high permeability may be appropriately allocated to pixels to be recorded with, for example, cyan ink, magenta ink, and yellow ink.

As described above, by replacing pixels to be printed with black ink in a random or pseudo-random manner, a unique pattern caused by the regular mask can be seen as compared with replacement using a regular mask. There is an effect that it becomes difficult.

FIG. 17 is an explanatory diagram showing an example of the influence of the recording position deviation on the drying property. FIG. 17 shows a case where a highly permeable ink to be recorded at a position where a pixel to be recorded with a low permeable ink is replaced is recorded at a fixed position,
The results of evaluating the effect on the drying property when the displacement is about 180 μm are shown. About 1
The shift of 80 μm is 3 in a 400 dpi recording apparatus.
This is a pixel shift. As the evaluation of dryness, in a low-temperature and low-humidity environment where drying is slow, and in a normal room temperature environment, for a solid area and a character area, respectively, for a solid area and a character area, the backside dirt in which the previously recorded content is transferred to the back side of a new recording sheet due to the overlapping of recording sheets The stain on the leading edge of the new recording sheet and the stain on the recording surface on the recorded recording sheet were evaluated because the new recording sheet was conveyed over the recorded recording sheet and rubbed with the leading edge. The larger the value, the worse the dirt.

As shown in FIG. 17, the ink having a high permeability is about 180 μm from the position on the recording medium where the original recording is to be performed.
It can be seen that even if it is shifted by m, the drying property is hardly affected. Therefore, the replaced ink having high permeability does not always need to be accurately recorded at the position where it should be originally recorded. At least, pixels to be formed of ink having low permeability are thinned out at a predetermined ratio, and pixels to be printed with ink having high permeability, which is substantially equal to the thinned out, may be added for printing. Since the ink having high permeability is dispersed and printed over the entire image, the ink is mixed with the ink having low permeability to improve the permeability of the ink having low permeability, and penetrates into the recording medium. Therefore, it is possible to avoid contamination of the medium by undried ink even during continuous printing. Of course, by recording the outline portion only with black ink having low permeability, bleeding peculiar to ink having high permeability can be suppressed, and an image having a sharp outline portion can be obtained.

Conversely, even in a printing apparatus that performs only one-way printing during normal printing in order to prevent a printing position shift and the like, printing with replaced high-permeability ink is allowed to be misaligned. It is possible to configure so that recording is performed when moving in the reverse direction when returning.

FIG. 18 is an explanatory diagram of an example of the width of the contour portion. In the figure, the portion indicated by cross hatching is a contour portion, and the portion indicated by oblique hatching is a portion for recording a part of pixels to be recorded with black ink with color ink. In the above-described example, the width of the outline is set to one pixel, and
An example in which pixels are recorded using only black ink has been described. The present invention is not limited to this, and the width of the outline may be two or more pixels. However, in the experiment, when the width of the outline increases, the black ink in the outline is pulled by the internal color ink, and a phenomenon that the outline becomes whitish occurs. Therefore, the width of the contour is preferably about 1 to 4 pixels.

The width of the contour can be arbitrarily selected within the range of 1 to 4 pixels. For example, when a shift is expected in the position recorded by the color ink as described above, the width of the outline portion may be set so that the recording pixels by the color ink do not deviate from the recording area. In addition, the width of the contour portion can be set according to, for example, environmental conditions or the ratio of replacement of pixels recorded with black ink. As a result, even in a high-humidity environment or when the ratio of replacing pixels to be printed with black ink increases,
It is possible to prevent the bleeding of the ink from the contour portion and obtain an image with sharp edges while maintaining the drying property.

Further, the rate at which pixels to be printed with black ink are replaced by pixels to be printed with color ink is not limited to the above example. The same applies to the ratio of adding pixels to be recorded with color ink by thinning out pixels to be recorded with black ink. To explain these percentages,
Images were recorded at several rates and characterized. FIG. 19 is an explanatory diagram of specific ratios of pixels for recording black, cyan, magenta, and yellow. Here, the case where all the pixels to be printed with the black ink are printed with the black ink is set to 100, and the ratio of the ink of each color is shown. For example, in the first specific example, 30% of the pixels to be printed with black ink are not printed by replacement or thinning out, but 70% are printed with black ink. Then, pixels of 10% of the total number of pixels are recorded using cyan ink (c), magenta ink (m), and yellow ink (y). FIG. 20 is a diagram illustrating an example of pixel replacement in the first specific example. For example, as shown in FIG. 20A, in an area of 6 × 10 pixels, all the outlines having a width of one pixel are printed with black ink, and the inner 4 × 10 pixels are printed.
It is assumed that nine of the eight pixels are recorded with cyan ink, magenta ink, and yellow ink, respectively. in this case,
The ratios of the black ink (k), cyan ink (c), magenta ink (m), and yellow ink (y) inside are
As shown in FIG. 20B, almost 70%, 10%, 10%
% And 10%.

Similarly, in the specific example 2 of FIG. 19, 36% of the pixels to be recorded with black ink are not recorded by replacing or thinning out, but 64% are recorded with black ink. Then, pixels of 12% of the total number of pixels are recorded with cyan ink (c), magenta ink (m), and yellow ink (y). In these examples, since the printing is performed with the color ink by an amount corresponding to the reduced number of the pixels to be printed with the black ink, the total ink amount is the same as when printing is performed using only the black ink. FIG.
14 is an explanatory diagram of an example of pixel replacement in a specific example 2. FIG. As in FIG. 20A, the 6 × 1 shown in FIG.
In the area of 0 pixels, all the outlines having a width of 1 pixel are recorded with black ink, and 1 of the internal 4 × 8 pixels are recorded.
It is assumed that two pixels are recorded by four pixels each with cyan ink, magenta ink, and yellow ink. in this case,
The ratio of the cyan ink (c), the magenta ink (m), and the yellow ink (y) recorded inside is shown in FIG.
As shown in FIG. 6, the recording density is approximately 12%, and the remaining little less than 64% (strictly, 62.5%) is recorded with black ink (k).

In Comparative Example 1 of FIG. 19, only 70% of the pixels to be printed with black ink are printed with black ink. Then, 30% of the total number of pixels is recorded using cyan ink (c) and magenta ink (m).
In this case, the number of pixels recorded with black ink is reduced by only 30%, but the number of pixels recorded with color ink is increased by 60% with two inks. Therefore, the total ink amount is 30% larger than when recording only with black ink. Become. In Comparative Example 2, 70% of the pixels to be printed with black ink
Only black ink, and cyan ink (c),
15% of the total number of pixels by magenta ink (m)
Record each. The total amount of ink is no different from the case of using only black ink. In Comparative Example 3, only 70% of the pixels to be printed with black ink were printed with black ink,
30% of the total number of pixels is recorded using cyan ink (c), magenta ink (m), and yellow ink (y). The total ink amount increases by 60%. In Comparative Example 4, only 55% of the pixels to be printed with black ink are printed with black ink, and 15% of the total number of pixels are printed with cyan ink (c) and magenta ink (m). The total amount of ink is no different from the case of using only black ink. In Comparative Example 5, 85% of the pixels to be printed with black ink are printed with black ink, and 15% of the total number of pixels are printed with cyan ink (c) and magenta ink (m). The total amount of ink is increased by 15% compared to the case of using only black ink. In Comparative Example 6, only 85% of the pixels to be printed with black ink were printed with black ink, and 15% of the total number of pixels were each printed with cyan ink (c), magenta ink (m), and yellow ink (y). Record. The total amount of ink is increased by 30% compared to the case of using only black ink.

FIG. 22 shows pixels recorded with black ink.
Replace or thin out and record with color ink
FIG. 7 is an explanatory diagram of an example of a difference in color due to color. Black in
When the pixels to be recorded with the ink are recorded with color ink,
The tint differs depending on the difference in coloring. For example, two
The color of CIEL^*a^*b^*In the color space (L^* ₁, A^* ₁,
b ^* ₁), (L^* _Two, A^* _Two, B^* _Two)
The difference △ E is E = ｛(L^* ₁-L^* _Two)^Two+ (A^* ₁-A^* _Two)^Two
+ (B^* ₁-B^* _Two)^Two｝^1/2... can be represented by (1)
You. FIG. 22 shows the case where all the recordings are made with black ink
And the color difference ΔE.

It is generally said that when ΔE <5, the color difference is not known. Comparing the color difference ΔE in each example shown in FIG. 22, the specific example has a small color difference.
Further, in the specific example 2 in which the ratio of the pixels recorded with the black ink is smaller than in the specific example 1, the color difference is slightly larger, but within the allowable range. Further, in Comparative Example 4 in which the ratio of pixels recorded with black ink was reduced, it was found that the color difference ΔE was 5 or more, exceeding the allowable range. As described above, by replacing the low-permeability black ink with the fast-permeability color ink, or by thinning out the low-permeability black ink and adding the color ink having the higher permeability, the permeability to the recording medium is improved. It is accelerated, but on the contrary, the color becomes worse. Therefore, it can be seen that the rate of replacing or thinning out pixels recorded with ink having low permeability is set to 40% or less, and the rate of pixels recorded with ink having low permeability is set to 60% or more.

As a color ink to be recorded by replacing the black ink, as shown in the specific example 1, cyan, magenta and yellow are used as a whole to be process black. Even a color or two colors is effective in improving the permeability. However, as can be seen from a comparison between Specific Example 1 and Comparative Example 2 in FIG. 22, when 10% each of the cyan ink, magenta ink and yellow ink is added, the color is changed to 15% each for the cyan ink and magenta ink. Even though the amount of ink is the same, the tint becomes worse. If the ink amounts of the cyan ink and the magenta ink are further increased to 30% as in Comparative Example 1, the color difference becomes more apparent and exceeds the allowable range. Even in this case, when 30% of the yellow ink is added, the color ink added becomes a color close to the process black, and the color difference is improved as shown in Comparative Example 3. In this way, the pixels recorded with black ink are replaced,
Alternatively, when adding pixels to be recorded with color ink, it is desirable to add pixels at a rate that is as close to black as possible. Of course, if the color difference is within the allowable range, it is replaced with only one or two color inks,
Alternatively, a pixel may be added.

FIG. 23 is an explanatory diagram showing an example of the difference in color tone and the drying property when recording with color ink by replacing or thinning out pixels to be recorded with black ink. FIG.
In No. 2, it has been described that the difference in tint increases when the proportion of pixels recorded with black ink is small. However, since black ink has low permeability, it can be easily presumed that if the ratio of pixels recorded with black ink is large, the drying property is deteriorated. As shown in FIG. 23 as Comparative Example 5 and Comparative Example 6, the ratio of pixels recorded with black ink is 8%.
If it is 5%, the drying property is poor, and the recording medium is stained. In order to keep the recording medium clean even during high-speed printing, the proportion of pixels recorded with black ink is about 80% or less, that is, the proportion of pixels recorded with black ink recorded with color ink, or the proportion of pixels recorded with black ink is reduced. It is desirable that the thinning rate be about 20% or more.

Further, as shown in the specific example 2, when the ratio of the pixels recorded with the black ink is smaller than that in the specific example 1, the drying property is further improved. Further, the ratio of pixels recorded with black ink is reduced, and the ratio of pixels recorded with black ink is 55% as in Comparative Example 4, and 15% for cyan ink, magenta ink, and yellow ink, respectively.
When recording is performed one by one, the drying property is more sufficient, but as described in the description of FIG. 22, the difference in the color tone becomes remarkable, exceeding the allowable range, which is inappropriate. That is, the proportion of pixels recorded with black ink is about 60% or more, that is, the proportion of pixels recorded with black ink recorded with color ink or the proportion of thinned pixels recorded with black ink is about 40% or less. desirable.

From these conditions, it is desirable that the ratio of printing pixels printed with black ink with color ink or the ratio of thinning out pixels printed with black ink be about 20% or more and about 40% or less. The rate at which pixels recorded with black ink are replaced or thinned is 2
What is necessary is just to select arbitrarily in the range of 0-40%.

FIG. 24 is a diagram for explaining the difference in color between forward recording and reverse recording during reciprocal recording. In FIG.
The difference between the color at the time of forward recording and the color at the time of re-recording is described in the above (1).
Shows the value calculated by the formula. In the arrangement of the recording heads as shown in FIGS. 2 and 3, since the recording order of each color is different as described with reference to FIGS. 13 and 15, during the forward recording, the cyan ink and the magenta ink are first recorded on the recording medium. The black ink is recorded after recording on the recording medium, but the black ink is recorded only by recording the yellow ink first on the recording medium at the time of reverse recording. Therefore, the color tone differs between the forward recording and the reverse recording.

In the first specific example, there is not much difference in the color tone as compared with the case where all the recordings are made with the black ink. In the specific example 2, the color order is affected by the increase in the amount of the color ink, and the color difference is increased.
Sufficient and within acceptable range. When the amount of the color ink is very large as in the specific example 3, the color difference becomes remarkable, and particularly in a low-temperature environment where drying is poor, a color difference exceeding an allowable range occurs depending on the paper quality.

When only the cyan ink and the magenta ink are used as the color inks, there is no highly permeable ink to be recorded first at the time of the reprinting. Therefore, as shown in Comparative Example 2, even if the amount of the black ink and the amount of the color ink are the same, the difference in the hues increases. Further, when the ink amounts of the cyan ink and the magenta ink are increased, as shown in Comparative Example 1, the color difference becomes remarkable and exceeds the allowable range.

As described above, the pixels to be recorded with the black ink are replaced with the pixels to be recorded with the color ink in the range of 20% to 40%, or the pixels to be recorded with the color ink by thinning out the range are added to the same extent. By printing one or more color inks having high permeability before recording black ink having low permeability, the arrangement order of the recording heads as shown in FIGS. It is possible to perform recording while suppressing the difference in color at the time of recording. Therefore, the recording method of the present invention is suitable when it is necessary to perform reciprocal recording, and by using the present invention, the difference in color between the band at the time of forward recording and the band at the time of re-recording is made inconspicuous. Recording can be performed, and a high-quality image can be obtained.

In the above description, for example, as shown in FIGS. 2 and 3, four colors of cyan, black, magenta, and yellow are used.
Four recording heads 11a, 11b, 11 corresponding to colors
Although described based on the example provided with c and 11d, the present invention is not limited to this. FIG. 25 is a configuration diagram showing an example of another recording head applied in the present invention. For example, in the configuration shown in FIG. 25A, a recording head having a nozzle row for ejecting ink with high permeability (cyan ink, magenta ink, and yellow ink) and a nozzle for ejecting ink with low permeability (black ink) It is composed of a recording head having only columns. In this configuration, the number of recording heads is small, so that the cost can be reduced, and the recording width of black can be widened, so that high-speed recording is possible. However, since the color recording head exists only on one side of the black recording head, it is necessary to perform unidirectional recording or to limit the recording width at the time of reciprocal recording.

In the configuration shown in FIG. 25B, a nozzle for ejecting highly permeable inks (cyan ink, magenta ink, and yellow ink) to one recording head is provided.
An example is shown in which nozzles that eject ink with low permeability (black ink) are arranged in one row. In this configuration, since the recording with the ink having low permeability is always performed after the recording with the ink having high permeability, it is expected that the difference in the color tone at the time of the reciprocal recording is reduced. Further, since only one recording head is required, cost reduction can be expected.

Further, the present invention is not limited to the configuration using inks of cyan (c), black (k), magenta (m), and yellow (y). For example, the present invention may be applied to monochrome recording, for example, when a monochrome image is formed using ink having high permeability and ink having low permeability for black. Further, for each color, ink having high permeability and ink having low permeability may be used. For example, low-permeability ink may be used as the dark ink, and low-permeability ink may be used as the light-color ink. Of course, other color combinations may be used.

Further, it is possible to switch whether or not to perform the process of recording a part of the pixels other than the outline of the region to be recorded with the ink having low permeability as described above with the ink having high permeability. Can be. For example, it can be set so that such processing is performed when the black / monochrome high-speed recording mode is selected. The above-described processing may not be performed in other monochrome recording modes or low-speed (or normal) recording nodes. Such switching may be performed by a switch that can be set by a user, or may be performed by a program that detects a header in a document and performs switch setting. Alternatively, it may be determined by analyzing an image to be recorded.

[0073]

As is apparent from the above description, according to the present invention, the outline of an image to be composed of low-permeability ink is recorded using the low-permeability ink. In the part of, pixels to be printed with ink having low permeability at a predetermined rate are replaced with pixels to be printed with ink having high permeability, or pixels to be printed with ink with low permeability at a predetermined rate are thinned out, and almost the same. Pixels to be recorded with ink with high permeability are added and recording is performed, so the sharpness of the outline is maintained, the difference in color tone is suppressed, the deterioration of image quality is minimized, and the drying property is improved. Thus, there is an effect that paper stains can be reduced even during high-speed recording.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an embodiment of an ink jet recording apparatus according to the present invention.

FIG. 2 is a perspective view illustrating a configuration example of a recording unit according to the embodiment of the inkjet recording apparatus of the present invention.

FIG. 3 is a front view illustrating a configuration example of a recording unit according to the embodiment of the inkjet recording apparatus of the invention.

FIG. 4 is an explanatory diagram of an example of a contour extraction method in a contour extraction unit.

FIG. 5 is an explanatory diagram of another example of the contour detection window.

FIG. 6 is an explanatory diagram of still another example of the contour detection window.

FIG. 7 is an explanatory diagram of an example of contour extraction in a color image.

FIG. 8 is an explanatory diagram (black) of an example of a specific operation of the pixel conversion unit according to the embodiment of the present invention.

FIG. 9 is an explanatory diagram (cyan) of an example of a specific operation of the pixel conversion unit according to the embodiment of the present invention.

FIG. 10 is an explanatory diagram (magenta) of an example of a specific operation of the pixel conversion unit according to the embodiment of the present invention.

FIG. 11 is an explanatory diagram (yellow) of an example of a specific operation of the pixel conversion section according to the embodiment of the present invention.

FIG. 12 is a diagram illustrating an example of a specific operation of the recording unit according to the embodiment of the present invention.

FIG. 13 is a diagram illustrating an example of a printing order using each ink.

FIG. 14 is a diagram illustrating an example of a process of penetrating ink into recording paper.

FIG. 15 is an explanatory diagram of another example of a printing order by each ink.

FIG. 16 is a diagram illustrating another example of the pixel replacement process in the pixel conversion unit according to the embodiment of the present invention.

FIG. 17 is an explanatory diagram of an example of an influence on a drying property due to a recording position shift.

FIG. 18 is an explanatory diagram of an example of a width of a contour portion.

FIG. 19 is an explanatory diagram of specific ratios of pixels for recording black, cyan, magenta, and yellow.

FIG. 20 is an explanatory diagram of an example of pixel replacement in a specific example 1;

FIG. 21 is an explanatory diagram of an example of pixel replacement in a specific example 2.

FIG. 22 is an explanatory diagram illustrating an example of a difference in hues caused by replacing or thinning out pixels to be printed with black ink and printing with color ink.

FIG. 23 is an explanatory diagram illustrating an example of a difference in color tone and a drying property by replacing or thinning out pixels to be recorded with black ink and recording with color ink.

FIG. 24 is an explanatory diagram of a difference in color between forward recording and reverse recording during reciprocal recording.

FIG. 25 is a configuration diagram showing an example of another recording head applied in the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Outline extraction part, 2 ... Pixel conversion part, 3 ... Recording part, 11a
11d: recording head, 12a to 12d: ink tank, 13: signal cable, 14: carriage, 15: guide rod, 16: carriage guide, 17: timing belt, 18: drive motor, 19: drive pulley, 2
0: Recording paper.

Claims (14)

[Claims] In an ink jet recording method in which recording is performed for each pixel using at least a low-permeability ink and a high-permeability ink, an outline of a pixel region to be constituted by the low-permeability ink is provided. Recording is performed using the low-permeability ink, and pixels to be formed of the low-permeability ink at a predetermined ratio are recorded using the high-permeability ink for the pixel regions other than the contour portion. An ink jet recording method characterized by recording by replacing pixels. 2. In an ink-jet recording method in which recording is performed for each pixel using at least a low-permeability ink and a high-permeability ink, an outline of a pixel region to be constituted by the low-permeability ink Recording using the low-permeability ink, the pixels to be formed of the low-permeability ink are thinned out at a predetermined ratio for the pixel area other than the contour portion, and the pixel area is substantially equal to the thinned-out amount. An ink jet recording method characterized by recording by adding pixels to be recorded using ink having high permeability. 3. The predetermined ratio for replacing or thinning out pixels to be constituted by the ink having low permeability is approximately 2%.
The inkjet recording method according to claim 1, wherein the content is 0% or more and 40% or less. 4. The method according to claim 1, wherein the replacement or thinning-out of the pixels to be constituted by the ink having low permeability is performed in a random or pseudo-random manner.
The inkjet recording method according to any one of the above items. 5. The method according to claim 1, wherein the printing of the pixel is performed by using the ink having low permeability after the printing of the pixel is performed using one or more kinds of ink having high permeability. The ink-jet recording method as described above. 6. The ink according to claim 1, wherein the ink having a low permeability is a black ink, and the ink having a high permeability is a cyan ink, a magenta ink, and a yellow ink. Item 6. The ink jet recording method according to item 1. 7. A method according to claim 1, wherein the recording is performed using the high-permeability ink for the pixel area other than the contour of the pixel area to be formed of the low-permeability ink. The ink jet recording method according to claim 6, wherein the yellow ink is used at a predetermined ratio. 8. In an ink jet recording apparatus that performs recording for each pixel using at least a low-permeability ink and a high-permeability ink, an outline of a pixel area to be formed by the low-permeability ink is extracted. Contour extracting means; pixel converting means for replacing pixels in the pixel area other than the contour portion including the contour extracted by the contour extracting means with pixels recorded with the highly permeable ink at a predetermined ratio; and An ink jet recording apparatus comprising: a recording unit that records an image processed by the unit using the low-permeability ink and the high-permeability ink. 9. An ink jet recording apparatus that performs recording for each pixel by using at least a low-permeability ink and a high-permeability ink to extract a contour of a pixel region to be formed by the low-permeability ink. Recording is performed using a contour extracting means, and thinning out the pixels of the pixel area other than the contour portion including the contour extracted by the contour extracting means at a predetermined ratio, using an amount of the highly permeable ink substantially equal to the thinned amount. An ink jet recording apparatus comprising: a pixel conversion unit that adds a pixel to be converted; and a recording unit that records an image processed by the pixel conversion unit using the low-permeability ink and the high-permeability ink. 10. The method according to claim 8, wherein the predetermined ratio of replacing or thinning out pixels to be formed with the low-permeability ink in the pixel conversion means is approximately 20% or more and 40% or less. An ink jet recording apparatus according to claim 9. 11. The pixel conversion device according to claim 8, wherein the pixel conversion unit replaces or thins out pixels to be formed of the ink having low permeability with random numbers or pseudo random numbers. Item 6. The ink jet recording apparatus according to item 1. 12. The printing device according to claim 8, wherein the printing unit prints the pixel with the ink having a low permeability after printing the pixel with one or more kinds of the ink having a high permeability. Alternatively, the ink jet recording apparatus according to claim 9. 13. The ink having a low permeability is a black ink, the ink having a high permeability is a cyan ink,
13. The ink jet recording apparatus according to claim 8, wherein the ink jet recording apparatus is a magenta ink and a yellow ink. 14. The pixel conversion unit according to claim 1, wherein when replacing or adding a pixel to be recorded with the highly permeable ink, the cyan ink, the magenta ink,
14. The inkjet recording apparatus according to claim 13, wherein pixels recorded with the yellow ink are used at a predetermined ratio.