JP3244890B2 - Color inkjet recording method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color ink jet recording method capable of recording a color image at a high density and a clear image, and more particularly, to yellow, magenta, cyan, or green, red, blue, etc. And a color ink jet recording method using a black ink such as black. The present invention can be applied to all devices using a recording medium such as paper, cloth, nonwoven fabric, OHP paper, and the like, and specific applied devices include office equipment such as printers, copiers and facsimiles, and mass production equipment.

[0002]

2. Description of the Related Art Ink jet recording methods are used in printers, copiers, facsimile machines and the like because they have low noise and low running cost, and are easy to downsize and color.

In general, in the color ink jet recording method, color recording is performed using three colors of cyan, magenta, and yellow, or four colors of ink with black added.

When the ink-jet recording method is applied to a color recording apparatus, it is necessary to use a special paper in order to obtain a color image having high color development without bleeding of ink. However, in recent years, inks having improved printability and improved printability on plain paper have been put to practical use. However, at present, the print quality is still at an insufficient level. The biggest factor is the quality of black images recorded in color images.

In general, when a color image is obtained on plain paper by an ink jet recording method, since a quick-drying ink having a high penetration rate into plain paper is used, the color image portion is of high quality without ink bleeding between colors. Image. However, the density of the black image portion is low, and so-called feathering, in which ink bleeds along the paper fibers, occurs. For example, when a black image is present in a color image portion as a background, the black image portion is relatively inconspicuous,
When the black image part exists independently of the color image part, there is a problem that the quality deteriorates. Further, when the black image is a character, the character becomes extremely blurred without sharpness, and the quality of the image is extremely reduced.

In order to obtain a high-quality image in which the density of the black image portion is high and feathering does not occur, it is necessary to discharge a relatively large amount of ink having a relatively low penetration rate into plain paper. However, in this case, bleeding of the black ink and the color ink occurs at the adjacent boundary between the black image portion and the color image portion, and the quality is significantly deteriorated.

[0007] As described above, the prevention of ink bleeding between black and each color and the improvement of color recording quality by simultaneously reducing the feathering of black have been contradictory issues.

Therefore, Japanese Patent Application Laid-Open No. 3-146355 proposes a method of not recording an area along the boundary between black and color. However, this method has a disadvantage that the recorded data changes.

Japanese Patent Application Laid-Open No. 4-15849 discloses a multi-color head for color recording and a head for character recording, and switches between the multi-color head and the head for character recording based on a recorded image. Recording methods have been proposed. However, in this method, since a character recording head is provided in addition to the conventional multi-color head for color recording, an increase in cost and an increase in the size of the apparatus are inevitable.

At present, a method has been considered in which a black region along the boundary between black and color is formed by over-printing color ink to prevent bleeding at the boundary between black and color. Here, the black formed using the color ink is referred to as P
It is called CBk (Process Color Bk). In principle, black can also be obtained by superimposing (mixing) three colors of Y, M, and C. However, a black image formed by mixing color inks in this way is different from a normal black ink. Poor coloring.

[0011]

An object of the present invention is to improve the above-mentioned drawbacks of the prior art, and to provide a black image having a high density and free from feathering and a color image or a black image even if the image is a mixture of a black image and a color image. An object of the present invention is to provide a color ink jet recording method capable of obtaining a high-quality image in which ink does not bleed between an image and a color image.

[0012]

In order to achieve the above-mentioned object, the present invention uses black ink and a plurality of color inks having a recording medium penetration characteristic different from the black ink in accordance with print data. Determining a region of a black image adjacent to a color image based on the recording data, wherein the black image region adjacent to the color image includes: A step of determining the number of dots of the black image in the specific area located at the boundary with the color image, and according to the number of dots of the black image in the specific area, at the boundary with the color image in the area of the black image, Changing a region to be formed as a black image by a combination of at least two or more of the plurality of color inks; Forming print data corresponding to an area formed as a black image by a combination of at least two of the color inks as print data formed by the plurality of color inks, and forming an image in accordance with the print data; And characterized by the following.

Further, in the changing step, a width of an area formed as a black image by a combination of at least two of the plurality of color inks from the boundary is changed.

In the above-described color ink jet recording method, a predetermined area located at a boundary with the color image among the black image areas adjacent to the color image may be replaced with a black pixel formed by the black ink and the plurality of colors. And at least two of the color inks are mixed color pixels, and the changing step changes the number of the mixed color pixels in the predetermined area.

Further, the color ink jet recording method of the present invention uses a black ink and a plurality of color inks having different recording medium penetration characteristics from the black ink, wherein each of the black ink and the multi-color ink is used. In a color ink jet recording method in which an image is ejected onto a recording medium with a time lag, and an image is formed on the recording medium according to the recording data, a step of determining an area of a black image adjacent to the color image based on the recording data Determining a color of an adjacent color image for a region of the black image determined to be adjacent to the color image; and determining a position of a black image region adjacent to the color image at a boundary with the color image. A predetermined area to be mixed with a black pixel by the black ink and a color mixture of at least two types of color inks of the plurality of color inks. It consists of a step of forming in a,
An image is formed by changing the ratio of the black pixels and the mixed color pixels forming the predetermined area according to the color determined in the determination step.

In the above-described color ink jet recording method, the color of the color image adjacent to the black image is
The ratio of the black pixels forming the predetermined area is increased as the color is recorded by the color ink ejected at a time difference from the ejection of the black ink.

Further, the black ink has a characteristic that the permeation speed of the black ink into a recording medium is lower than that of the plurality of color inks.

Further, the plurality of color inks are yellow, magenta and cyan.

Hereinafter, the present invention will be described in detail.

According to the present invention, for example, for a black ink requiring high-quality black characters, an ink having a relatively low permeation rate to a recording paper is used, and a color ink for obtaining a color image in which ink does not bleed between colors is used. With respect to the method (1), a quick-drying ink having a high ink penetration rate into the recording paper is used, and a high image quality without ink bleeding at an adjacent boundary between a black image and a color image is realized.

In the present invention, it is determined whether or not a black image and a color image are adjacent to each other. If adjacent, a part or all of the black image is formed by color ink or a mixture of color ink and black ink. The black image adjacent to the color (yellow) image shown in FIG. 1 is formed by, for example, performing the processing shown in FIG.

That is, as shown in FIG. 2 (a), only the boundary portions adjacent to the yellow image are yellow, magenta and cyan.
FIG. 2 (b), which is formed by a kind of color ink.
As shown in FIG. 2C, all the black images are formed by the three types of color inks. As shown in FIG. 2C, two pixels of the black image adjacent to the yellow image are formed by the three types of color inks and the black ink. And all the black images are formed by mixing the three types of color ink and black ink as shown in FIG. 2D.

In the case of FIG. 2A, only one pixel at the boundary of the black image adjacent to the yellow image is formed with three types of color inks and the other black image portions are formed with black ink. Has a high density, but causes some ink bleeding between the yellow and black images.

In the case of FIG. 2B, since the black image is formed only by three kinds of color inks, no ink bleeding occurs between the yellow image and the black image. The density is slightly lower than that, and depending on the characteristics of each color ink, there is a possibility that a hue difference may occur between the color image and the black image formed with the black ink.

In the case of FIG. 2C and FIG. 2D, since black ink is mixed in addition to color ink, the occurrence of a density difference between a black image formed only with black ink and a black image is reduced. However, on the other hand, since the black ink is mixed, ink bleeding easily occurs between the yellow image and the black image.

As shown in FIG. 2A or FIG. 2B, when a black image adjacent to a color image is formed by mixing color inks, it is effective to change the area according to information of the adjacent color image. is there. For example, when the printing ratio of adjacent color images is low, only the adjacent portion is formed with color ink, while when the printing ratio of adjacent color images is high, image quality is improved by forming a plurality of pixels from the boundary with color ink. Can be. Further, the area of the black image formed by the color ink may be changed according to the printing ratio of the adjacent black image.

When forming by mixing color ink and black ink as shown in FIG. 2 (c) or FIG. 2 (d),
It is also effective to change the mixing ratio of the black ink according to the information of the adjacent color image. For example, when the printing ratio of adjacent color images is high, the mixing ratio of black ink is reduced as shown in FIG. 2C, while when the printing ratio of adjacent color images is low, the black ink is mixed as shown in FIG. By increasing the mixing ratio, the image quality can be improved. Further, the mixing ratio of the black ink may be changed according to the printing ratio of the adjacent black image.

The range of the black image area formed by combining two or more of the black ink and the color ink is 0.
% (All formed with black ink) to 100% (all formed with a combination of two or more inks).

The combination of the black ink and the color ink is appropriately set in accordance with the coloring characteristics of each ink. However, from the viewpoint of the density of the black image area and the bleeding of the ink in the adjacent area, the combination is considered. The mixing ratio of the black ink at the time can be changed from 0% to 100%.

The outline of the present invention has been described above. Hereinafter, the present invention will be described in detail with reference to embodiments.

[0031]

【Example】

(First Embodiment) FIG. 3 is a schematic view of a printer to which the color ink jet recording method of the present invention is applied.
1y is a recording head for yellow-ink, 1m is a recording head for magenta ink, 1c is a recording head for cyan ink,
2 is a carriage on which a recording head is mounted, 3 is a flexible cable for sending an electric signal from the printer body to the recording head, 4 is a cap unit having recovery means, 5
y, 5m, 5c, 5k are recording heads 1y, 1m, 1c,
A cap member corresponding to 1k, a wiper blade 6 made of a member such as rubber, and a recording paper 7 held opposite to the recording head.

The four recording heads mounted on the printer have 64 ejection ports formed at a density of 360 per inch at the portion where each recording head faces the recording paper. Each of these discharge ports is provided with an ink liquid path communicating with the discharge port, and a common liquid chamber for supplying ink to these liquid paths is provided behind a portion where the ink liquid path is provided. Can be An ink path corresponding to each of the discharge ports is provided with an electrothermal converter that generates thermal energy used to discharge ink droplets from these discharge ports, and an electrode for supplying power thereto. I have.

Approximately 40 ng of ink is ejected from the ejection openings of the recording heads 1y, 1m, and 1c, and approximately 80 ng of ink is ejected at a frequency of 6.3 KHz from the ejection openings of the recording head 1k. That is, in the present embodiment, the discharge amount of the black ink is designed to be larger than the discharge amounts of the other color inks. Further, the setting of the ejection amount is not limited to being determined by the design of the print head, but may be controlled so that the energy for ejecting the ink is adjusted and the black ink is ejected more than the other color inks. .

As the color ink supplied to the recording heads 1y, 1m, and 1c, a color ink having a high permeation rate to the recording paper is used so as to prevent the ink from bleeding at the boundary between colors when a color image is formed. On the other hand, the black ink supplied to the recording head 1k has a relatively higher permeation speed to the recording paper than the above three types of color inks, so that the black image has high density and little feathering. The slower one is used.

Specifically, inks of the following components were used as the inks of each color. 1. Yellow C.I. I. Direct Yellow 86 3 parts Diethylene glycol 10 parts Isopropyl alcohol 2 parts Urea 5 parts Acetylene EH (Kawaken Chemical) 1 part Water balance 2. Magenta C. I Acid Red 289 3 parts Diethylene glycol 10 parts Isopropyl alcohol 2 parts Urea 5 parts Acetylene EH (Kawaken Chemical) 1 part Water remainder 3 parts Cyan C.I. 3. I Direct Bull-199 3 parts Diethylene glycol 10 parts Isopropyl alcohol 2 parts Urea 5 parts Acetylene EH (Kawaken Chemical) 1 part Water remaining part 4. Black C.I. I Direct Black 154 3 parts Diethylene glycol 10 parts Isopropyl alcohol 2 parts Urea 5 parts Water balance

Thus, CMY has improved permeability by adding 1% of acetylenol EH to Bk. Other additives include other surfactants and alcohols.

FIG. 4 is an electric control block diagram of the above-described color ink jet printer.

Reference numeral 301 denotes a system controller for controlling the entire apparatus, and a storage element (ROM) containing a microprocessor and a control program therein,
A storage element (RAM) and the like used when the microprocessor performs processing are arranged.

Reference numeral 302 denotes a driver for moving the print head in the main scanning direction. Similarly, reference numeral 303 denotes a driver for moving the print head in the sub scanning direction. Reference numerals 304 and 305 denote motors corresponding to the driver, which operate by receiving information such as speed and moving distance from the driver.

Reference numeral 306 denotes a host computer for transferring information to be printed to the printing apparatus of the present invention. Reference numeral 307 denotes a reception buffer for temporarily storing data from the host computer.
The data is stored until data is read from the first system controller. Reference numeral 308 denotes a memory for expanding data to be printed into image data, and has a memory size required for printing. Reference numeral 309 denotes a storage element for temporarily storing data to be printed, the storage capacity of which changes depending on the number of nozzles of the print head.

Reference numeral 310 denotes a print control unit for appropriately controlling the print head in accordance with a command from the system controller, and controls a discharge speed, the number of print data, and the like. 311
Is a driver for driving the heads 312Y, 312M, 312C, and 312Bk, and is controlled by a signal from the print control unit 310.

FIG. 5 shows an operation flow of this embodiment.

In STEP 1, the data is transferred from the host computer 306 in FIG. 4, and the data stored in the reception buffer 307 is read by the system controller 301. Next, in STEP 2, attention is paid to black data among the data read in STEP 1, and it is determined whether or not color recording data exists at a position adjacent to the periphery of the black image recording area. If there is no color image data adjacent to the black image data, the data of the black image and the color image are developed in the buffers for each color in STEP3, and yellow, magenta, The recording operation is performed by the recording heads for cyan and black inks.

On the other hand, if it is determined in STEP 2 that there is a color image adjacent to the black image, STEP 4
The number of black print dots in the specific area is counted. That is, as shown in FIG. 6, the black image area at the boundary adjacent to the color image is divided into 2 × 2 four-pixel areas S, and the number of black print dots in this area S is counted. If the number of black ink dots in the area S is 2 or less, the processing is performed in STEP5, and if the number of black print dots in the area S is 3 or more, the processing is performed in STEP6.

In STEP 5, since the number of black print dots in the area S is relatively small, a process of printing only the black image adjacent to the color image with a plurality of color inks as shown in FIG. Will be That is, the black image data for one pixel adjacent to the color image is developed in C, M, and Y buffers for color ink printing, and the remaining black image data is developed in the Bk buffer for black ink printing. I do.

In STEP 6, since the number of black print dots in the area S is 3 or more and the number of black print dots is relatively large, as shown in FIG. Processing such as printing an image with a plurality of color inks is performed. That is, the black image data for two pixels adjacent to the color image is developed into C, M, and Y buffers for printing color ink, and the remaining black image data is developed into a Bk buffer for printing black ink. .

After the predetermined processing in STEP5 or STEP6 is completed, in STEP7, the recording operation is performed by the respective recording heads. That is, when the STEP 5 process is performed, printing is performed by superimposing another color ink on one pixel of the black image adjacent to the color image. When the processing is performed in STEP 6, the recording is performed by printing two pixels of the black image adjacent to the color image by overlapping the color ink.

As described above, according to the present embodiment,
A part of the black image adjacent to the color image is formed by mixing color inks, and if the number of black printing dots in the adjacent part is small, the width of the black image formed by mixing color inks is reduced, and conversely, If the number of black print dots in the portion is large, the width of the black image formed with color ink is widened, so that ink bleeding is unlikely to occur at all times, and it is necessary to prevent a significant density difference in the black image from occurring. it can.

(Second Embodiment) In the first embodiment described above, a case where a part of a black image adjacent to a color image is formed with color ink has been described. In this embodiment, a part of a black image is formed. Is formed using a combination of black ink and color ink.

FIGS. 8A and 8B show a specific example of forming a black image using a combination of black ink and color ink. The former shows a case where one of the four pixels is printed with black ink and the remaining three pixels are formed with three types of color inks, and the latter shows two of the four pixels printed with black ink and the remaining two pixels are printed. Is formed with three types of color inks.

This embodiment differs from the first embodiment in the processing of STEP5 and STEP6 of the processing shown in FIG.

This embodiment will be described with reference to the flowchart shown in FIG.

In the processing of the flowchart shown in FIG. 5, if the number of black print dots in the area S is 2 or less in STEP 4, the black image data is processed in STEP 5 in accordance with the pattern shown in FIG. Is expanded to the buffer of each color. That is, black image data corresponding to two pixels to be printed with black ink is developed in a Bk buffer,
Black image data corresponding to two pixels to be printed with the color ink is developed in Y, M, and C buffers.

If the number of black print dots in the area S is three or more, the black image data is developed in the buffer of each color in STEP 6 according to the pattern shown in FIG. That is, black image data corresponding to one pixel to be printed with black ink is developed in a Bk buffer,
Black image data corresponding to three pixels to be printed with color inks is developed in Y, M, and C buffers.

As described above, a part of the black image adjacent to the color image is formed with color ink, and if the number of black print dots in the adjacent portion is small, the number of pixels formed by mixing color ink is reduced. In addition, if the number of black print dots in the adjacent portion is large, the number of pixels formed by mixing color inks is increased, so that ink bleeding is unlikely to always occur, and a remarkable density difference in a black image does not occur. Can be

In this embodiment, since a part of the black image adjacent to the color image is formed by a combination of the black ink and the color ink, a high-density image can be obtained, and furthermore, according to the image information of the black image. Since the combination of the black ink and the color ink is changed, a high-density black image can be realized on the recording medium without blurring the ink.

(Third Embodiment) FIG. 9 is a schematic view of another color ink jet printer to which the present invention can be applied.

The carriage 101 has a print head 102 and a cartridge guide 103 mounted thereon, and can scan on a guide shaft 104 and a guide shaft 105.

The recording paper 106 is fed into the main unit by a paper feed roller 107, is sandwiched between a paper feed roller 108, a pinch roller (not shown), and a paper holding plate 109, and is sent to the entire surface of the paper feed roller 102. Printed. Two types of ink cartridges, a color ink cartridge 110 containing three colors of yellow, magenta, and cyan, and a black ink cartridge 111, which are separately inserted into the cartridge 103, are provided.
Communicate with

The same yellow, magenta, and cyan inks as those stored in the first embodiment were used in the color ink cartridge 110.

The recording head 102 will be described in more detail with reference to FIG. 10. In the front portion of the recording head 102, yellow, magenta, cyan, and black discharge port groups are arranged in a straight line. Each group has 24 ejection openings for yellow, magenta, and cyan, and 64 ejection openings for black, and the interval between colors is equal to or greater than the nozzle pitch.

Each of these discharge ports is provided with an ink liquid path communicating with the discharge port, and a common liquid for supplying ink to these liquid paths is provided behind the portion where the ink liquid path is provided. A room is provided. An ink liquid path corresponding to each of the discharge ports is provided with an electrothermal converter that generates thermal energy used for discharging ink droplets from these discharge ports and an electrode wiring for supplying power thereto. ing. These electrothermal transducers (discharge heaters) and electrode wires are formed by a film forming technique on a 201 substrate made of silicon or the like. Further, on this substrate, a resin, a partition made of a glass material,
The discharge port, the ink liquid path, and the common liquid chamber are formed by stacking a top plate and the like. Further behind, a drive circuit for driving the electrothermal transducer based on a recording signal is provided in the form of a printed circuit board.

Alternatively, without using the glass material, a grooved top plate (orifice plate) provided with partitions for partitioning a plurality of ink flow paths, a common liquid chamber, and the like, and the substrate are bonded together. It may be configured to be formed. The grooved top plate is integrally molded, and the integral molding material is preferably polysulfone, but other molding resin materials may be used.

The silicon substrate and the printed circuit board 202 are parallel to the same aluminum plate 203,
Reference numerals 04 to 207 protrude from a plastic member 208 called a distributor extending in the vertical direction with respect to the silicon substrate, and further communicate with an internal flow path, which communicates with a common liquid chamber.

There are four flow paths in the distributor, one for yellow, one for magenta, one for cyan, and one for black, which connect respective common liquid chambers and pipes.

Although the present embodiment employs a configuration in which the ink tanks can be replaced independently for the color ink and the Bk ink, a disposable recording head in which the ink tank and the print head are integrated may be used. .

The yellow provided on the recording head 102
, 40 m from the ejection port for magenta and cyan
Is about 80n from the black orifice
g of ink is ejected.

As compared with the ink jet recording apparatus of FIG. 3 shown in the first embodiment, although the recording time is increased by a plurality of scans because the recording heads are arranged vertically, the difference between different colors Since there is a certain time interval between recordings, there is an advantage that bleeding between different colors is reduced.

FIG. 4 is a block diagram showing the electrical control of the color ink jet printer used in the present embodiment, as in the first embodiment.

FIG. 11 illustrates a recording operation when printing a color image (including a mixture of black images) using the print head 102. FIG. 11 (a) shows a black image in yellow ink. An image with "Y" printed, "M" printed with magenta ink, and "C" printed with cyan ink is shown. Hereinafter, the process of printing this image will be described.

In FIG. 11B, a black image is printed by a nozzle (ejection port) for black ink. At this time, 24 nozzles are used counted from the top in the figure. After the printing is completed, the recording paper is fed by 24 nozzles, and as shown in FIG. 11C, a black image is printed by the nozzles for black ink. Subsequently, after the recording paper is fed by 24 nozzles, as shown in FIG. 11D, a black image is printed by the nozzle for black ink, and a part of "C" is printed by the nozzle for cyan ink. .

Subsequently, after the recording paper is fed for 24 nozzles, as shown in FIG. 11E, a black image is printed by the nozzles for black ink, and a part of "C" is printed by the nozzles for cyan ink. . Subsequently, after the recording paper is fed for 24 nozzles, FIG.
As shown in (f), the nozzle for cyan ink is “C”.
The remaining part is printed with a part (corresponding to the upper half) of "M" by a nozzle for magenta ink. Next, 24 sheets of recording paper
As shown in FIG. 11 (g), a part of "M" (corresponding to the lower half) of the magenta ink nozzle
Is printed with a part of “Y” by a nozzle for yellow ink. Subsequently, after the recording paper is fed for 24 nozzles, FIG.
As shown in (h), the yellow ink nozzle
After printing a part of Y "and sending the recording paper, FIG.
As shown in (2), the remaining portion of "Y" is printed by the yellow ink nozzle, and printing of all images is completed.

As is apparent from the above recording operation, when the recording head used in this embodiment is used, the first and second recording heads are used.
The black image and the color image are not adjacent to each other in the same scan of the recording head as in the embodiment. The color image is adjacent to the black image in separate scans, in which the color image that is the earliest to the black image is the cyan image, followed by the magenta image and the yellow image. That is, when these three primary color images are adjacent to the black image, ink bleeding becomes significant in this order.

In consideration of the above characteristics, in this embodiment, the method of forming a black image adjacent to a color image is made different depending on the print information of the color image adjacent to the black image. A specific example will be described with reference to FIG. explain.

FIG. 12A shows a pattern for printing a black image when at least a cyan dot exists adjacent to the black image. In the example shown in FIG. 12 (a), only one pixel out of four 2 × 2 pixels located in the black image at the boundary is formed with black ink, and the remaining three pixels are formed by mixing color ink. Record with images.

The same applies to an image in which dots adjacent to a black image are mixed colors of cyan and other colors. In other words, the blue dots formed by mixing cyan and magenta and the green dots formed by mixing cyan and yellow are also shown in FIG.
Recording is performed as shown in FIG.

FIG. 12B shows a case where the dots adjacent to the black image are other than cyan and at least magenta dots are present. Two out of four pixels are black ink and the remaining two pixels are black. Is formed with a mixed color of color inks. The same applies to a case where a dot adjacent to a black image is a red dot formed by a mixture of yellow and magenta. FIG.
(C) shows a case where only yellow dots exist adjacent to a black image. Even when a black image and a color image are adjacent to each other, the black image is entirely formed with black ink.

FIG. 13 shows an outline of the operation flow of this embodiment. The difference from the first and second embodiments is that a step of detecting which color a black image is adjacent to is added. It is.

First, in step 8, it is determined whether or not a black image is adjacent to a color image. If there is no color image adjacent to the black image, data of each color is developed in a buffer corresponding to each color in step 14, Recording is performed in step 15. If it is determined that there is a color image adjacent to the black image, the color image adjacent to the black image is determined next.

For the determination of the adjacent color image, first, in step 9, it is determined whether or not the black image is adjacent to the cyan dot. If adjacent, at step 10,
FIG. 12 shows a boundary portion between a color image and an adjacent black image.
A process for forming a black image in the pattern shown in FIG. If the black image is not adjacent to the cyan dot in step 9, then it is determined in step 11 whether the black image is adjacent to the magenta dot.
At step 12, a process of forming a boundary portion between the black image and the magenta dot with the pattern shown in FIG. 12B is performed.

If it is determined in step 11 that the black image is not adjacent to the magenta dot, it is determined that the black image is adjacent only to the yellow dot. Therefore, the boundary portion of the black image is determined by the pattern shown in FIG. Is performed. The data of each color according to the pattern formed in steps 10, 12, and 13 is stored in the buffer of each corresponding color in step 14, and then recording is performed in step 15.

As described above, according to this embodiment, the color information of the color image adjacent to the black image is taken into account by taking into account the time difference between the black image and the adjacent color image caused by the form of the recording head used. Changes the method of forming a black image. As a result, the rate of forming a black image adjacent to the color image with the black ink increases without causing ink bleeding, so that a higher quality image can be obtained.

As shown in FIG. 14, for example, when the yellow image and the cyan image adjacent to the black image are adjacent to each other, the pattern of the black image adjacent to the yellow image and the pattern of the black image adjacent to the cyan image are obtained. If the recording pattern of the black image at the boundary portion is unified to the portion having the smaller number of dots printed with black ink, ink bleeding does not occur in the portion where the negative electrode overlaps.

(Fourth Embodiment) In the first, second, and third embodiments, when a black image exists adjacent to a color image, a black image is formed in accordance with the black image or image information of the color image. The way you do it. The common feature of these embodiments is that a black image is formed with a plurality of colors of ink.
It is desirable that the landing position of each color dot on the recording paper be controlled with high precision. In particular, in the formation of a black image, the sharpness of the edge of the image is one of the important factors for improving the image quality. Therefore, it is better that the landing position has a higher precision than that of the normal color image formation.

Although the distance between the recording head and the recording paper may be shortened in order to improve the landing position accuracy of the printing dots, there is a limit in the structure of the printer. Further, if the ejection frequency of the ink from the recording head is reduced, the landing position accuracy is generally improved, but the recording speed is reduced.

Therefore, in this embodiment, the frequency is changed only when the black image and the color image are adjacent to each other. That is, the second
In the third embodiment, when a black image and a color image are not adjacent to each other, printing is performed at a frequency of 6.3 KHz, and when a black image and a color image are adjacent to each other, printing is performed at a frequency of 4 KHz. Thus, an image in which the edges of the black image were sharper than the images obtained in the first to third embodiments could be obtained.

(Fifth Embodiment) In the third embodiment, a case has been described in which a black image formed by mixing color inks is formed of three types of inks of yellow, magenta, and cyan in each pixel.

In the present embodiment, when forming a black image with a mixture of color inks, instead of using three types of color inks uniformly, the type of ink to be printed for each pixel is changed as shown in FIG. To form an image.

That is, in the pattern shown in FIG. 12 (a), two pixels at the boundary of the black image adjacent to the color image
Of the × 2 four-pixel pattern, three pixels were formed by mixing three types of color inks.
As shown in FIG. 5A, two of the four pixels are formed by mixing three types of color inks, and the remaining one pixel is formed by mixing two types of yellow and cyan color inks. FIG. 12 (b)
2 out of 4 pixels at the boundary in the pattern shown in FIG.
As shown in FIG. 15B, one pixel formed by mixing three color inks and one pixel formed by mixing two color inks of yellow and cyan were formed as shown in FIG.
It is formed by mixing pixels.

As a result, the hue of the black image portion printed according to the pattern of FIG. 15 was closer to the hue of the black image portion printed with black ink as compared with the third embodiment.

By using the pattern shown in FIG. 15 at the boundary of the black image adjacent to the color image, the same effect as in the above-described embodiment can be obtained.

(Other Embodiments) In the first embodiment, the width of forming the boundary portion of the black image adjacent to the color image with the color ink is one pixel or two pixels depending on the number of printing dots of the black image. However, the present invention is not limited to this, and may be appropriately set according to the ejection frequency and ejection amount of the ink, the characteristics of the ink used, and the like.

For example, in the first embodiment, printing is performed at a frequency of 6.3 KHz. However, when printing is performed at a higher frequency, ink bleeding is likely to occur. It may be increased to three pixels or more, and the image quality can be further improved.

In the second embodiment, the black image adjacent to the color image is formed by mixing the black ink and the color ink. However, the mixing ratio of the black ink is not limited to this. Alternatively, it may be changed according to the ejection amount of the ink. Further, the black image forming area formed by mixing the black ink and the color ink is not limited to two pixels.

For example, if the discharge amount of the black ink is set to 90 ng in order to obtain a high-density black image, ink bleeding is likely to occur. Therefore, it is preferable to reduce the mixing ratio of the black ink. Specifically, when the number of black print dots in the specific area S is 2 or less, one of the 4 pixels is formed with black ink and 3 pixels are formed with color ink, and the number of black print dots in the specific area S is 3 or more. In some cases, bleeding can be prevented by forming all four pixels with color ink.

In the second embodiment, the number of dots printed by the black ink in the pattern consisting of four pixels at the boundary between the color image and the adjacent black image is changed.
The width of the black image area may be changed at the same time by using the configuration described in the embodiment.

Further, in the third embodiment, the number of black print dots of the difference for forming a black image is changed according to the color information of an adjacent color image. The color information at this time is particularly such that the number of dots printed with black ink is changed depending on which of cyan, magenta and yellow is adjacent. However, considering the secondary colors, that is, red, blue and green, High-quality images can be obtained.

For example, as shown in FIG. 15, when the image is adjacent to the yellow image, four of the patterns of the adjacent boundary portion are used.
When all pixels are black ink, and when adjacent to the magenta image, three of the four pixels are black ink and one pixel is color ink.
When adjacent to the cyan image, two out of four pixels are black ink and two pixels are color ink, and when adjacent to the red and green images, one out of four pixels is black ink and three pixels are color ink, and blue In the case where the image is adjacent to the image No. 4, all four pixels may be formed with color ink.

In each of the above-described embodiments, the determination of the image
A case has been described in which control / processing means such as determination processing, image expansion processing / replacement processing, etc. are all controlled by the control unit in the recording apparatus based on data received from the host computer. It is not limited.

For example, it is also possible to extend all of the control / processing means to a system in which the printer driver or the like executes the processing on an external device and receives actual recording data after the pixel replacement processing is completed. In many cases, the external device connected to the recording device is a host computer,
The host computer has better processing power and RAM capacity for performing the above processing.

Further, the image determination processing may be performed by the host computer, and the image development processing may be performed by the printer.

In the above-described embodiment, the so-called bubble jet recording method in which bubbles are generated in the ink by the electrothermal transducer and the ink is caused to fly by the action of the bubbles has been described. Needless to say, the present invention can also be applied to a so-called piezo-type ink jet recording system in which ink is caused to fly.

The present invention particularly provides an excellent effect in a recording apparatus using an ink jet recording head which performs recording by forming a flying liquid by utilizing thermal energy among ink jet recording methods.

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

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

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

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

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

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

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

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

[0112]

As described above, according to the present invention, it is possible to reduce the color bleeding of the black ink and other color inks while maintaining the quality of the black image.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of an image for explaining the present invention.

FIG. 2 is a diagram showing an example of a processed image for explaining the present invention.

FIG. 3 is a diagram illustrating a printer used in the first embodiment.

FIG. 4 is a control circuit block diagram of the printer used in the first embodiment.

FIG. 5 is an operation flow of the first embodiment.

FIG. 6 is a diagram illustrating an area that divides an adjacent boundary portion in the first embodiment.

FIG. 7 is a diagram illustrating a processed image in the first embodiment.

FIG. 8 is a diagram illustrating a processed image in the second embodiment.

FIG. 9 is a diagram illustrating a printer used in a third embodiment.

FIG. 10 is a diagram illustrating a recording head mounted on a printer used in a third embodiment.

FIG. 11 is a diagram illustrating a recording operation by a recording head used in a third embodiment.

FIG. 12 is a diagram illustrating a processed image according to a third embodiment.

FIG. 13 is a diagram illustrating a process according to the third embodiment.

FIG. 14 is a diagram illustrating an example of an adjacent boundary portion in the third embodiment.

FIG. 15 is a diagram illustrating a processed image in a fifth embodiment.

FIG. 16 is a diagram illustrating a processed image according to another embodiment.

[Explanation of symbols]

101 Carriage 102 Print Head 103 Cartridge 110 Color Ink Cartridge 111 Black Ink Cartridge 301 System Controller 302 Carriage Motor Driver 306 Host Computer 307 Receive Buffer 308Y, 308M, 308C, 308Bk Frame Memory for Each Color 309Y, 309M, 309C, 309Bk Data Buffer for Each Color 310 Print control unit 311 Print driver 312Y, 312M, 312C, 312Bk Print head of each color

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Nobuyuki Kuwahara 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Nao Yaegashi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inside the Company (72) Inventor Shoji Otsuka 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Atsushi Arai 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Kentaro Yano 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Kiichiro Takahashi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Invention Person: Osamu Iwasaki, 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Daigoro Kanematsu 3-30-2, Shimomaruko, Ota-ku, Tokyo Within Canon Inc. (58) Field surveyed (Int. Cl. ⁷ , DB name) B41J 2/21

Claims (9)

(57) [Claims] 1. A color inkjet recording method for forming an image on a recording medium in accordance with recording data using black ink and color inks of a plurality of colors having recording medium penetration characteristics different from the black ink. A black image adjacent to a color image based on the recording data
A step of determining the area, among the areas of the black image adjacent to the color image, the mosquito
Determining the number of dots a black image in a specific region located at the boundary between the color image, depending on the number of dots a black image of the specific area, the black image
At the boundary between the color image region, at least two or more combinations of the plurality of color inks
Changing a region to be formed as a more black image ; and changing the plurality of color inks in the black image region.
A black image is formed by combining at least two types.
The recording data corresponding to the area to be
Print data to be formed with ink
A step of forming an image in the color ink jet recording method. (2) The changing step includes changing the color of the plurality of colors.
-Black due to combination of at least two inks
Change the width of the area to be formed as an image from the border
The color ink jet according to claim 1, wherein
Record method. (3) Black image area adjacent to the color image
A predetermined area located at a boundary with the color image
The black pixels by the black ink and the color images of the plurality of colors.
Color mixture pixels of at least two types
In addition to forming The changing step includes the step of changing the color mixture image within the predetermined area.
The power of claim 1, wherein the number of primes is changed.
Color ink jet recording method. 4. Use of black ink and a plurality of color inks having different recording medium penetration characteristics from the black ink,
The black ink and the multicolor inks
In a color ink jet recording method in which an image is ejected onto a recording medium at a time difference and an image is formed on the recording medium according to the recording data, the area of a black image adjacent to the color image is determined based on the recording data.
Determining an area ; determining a color of an adjacent color image for an area of the black image determined to be adjacent to the color image; and determining a color of the black image area adjacent to the color image. predetermined region located on the boundary between the steps of: forming in the mixed-color pixel by at least two kinds of color mixing of the plurality of color inks and black pixels by the black ink, composed, determined in the determining step According to the color
The black pixel forming the predetermined area and the mixed color
A color ink jet recording method, wherein an image is formed by changing a ratio with a pixel . 5. The color of a color image adjacent to the black image
Of the ink ejected with a time lag from the ejection of the black ink
The more the color recorded by the color ink ,
5. The color ink jet recording method according to claim 4 , wherein the ratio of the black pixels forming an area is increased . 6. The black ink is a color ink of the plurality of colors.
Has a characteristic that the permeation speed into the recording medium is slower than ink
A power supply according to any one of claims 1 to 5, characterized in that:
Color ink jet recording method. 7. The color ink of the plurality of colors is yellow,
The color ink jet recording method according to any one of claims 1 to 6 , wherein the color ink jet recording method comprises magenta and cyan. 8. The method according to claim 1, wherein the ink is ejected by a mechanical pressure applied to the ink.
7. The color ink jet recording method according to any one of items 7 . Wherein said ink according to any one of claims 1 to 7, wherein the ejected by pressure based on the state change by heat in the ink, color ink jet recording method.