JP3253143B2 - 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 with high clarity and high density. More specifically, the present invention relates to a yellow (Y), magenta (M), cyan (C), or green ( The present invention relates to a color ink jet recording method using color inks such as G), red (R), blue (B), and black (Bk) ink.

[0002] The present invention relates to paper, cloth, nonwoven fabric, and OHP.
The present invention can be applied to all devices using a recording medium such as paper, and specific devices include a printer, a copier, a facsimile, and the like.

[0003]

2. Description of the Related Art Ink jet recording methods are used in printers, copiers, facsimile machines and the like because of their low noise, low running cost, easy downsizing of the apparatus, and easy colorization.

In general, the color ink jet recording method uses three color inks of C, M, and Y, and further performs color recording using four color inks including Bk.

In the conventional ink jet recording method, it was necessary to use a special paper having an ink absorbing layer in order to obtain a high-colored color image without bleeding of the ink. A method of giving printability to "plain paper" used in large quantities in a machine or the like has also been put to practical use. However, the printing quality on “plain paper” has not yet reached a sufficient level. The biggest factor is compatibility between ink bleeding between colors and black recording quality (particularly black character recording quality).

[0006]

Generally, when a color image is obtained on plain paper by an ink jet recording method, a quick-drying ink having a high penetration rate into plain paper is used. This results in a high-quality image with no ink bleeding between the colors. However, the density is low as a whole, and so-called feathering, where the ink slightly bleeds along the paper fibers around the recording image area of each color. Rings are likely to occur.

[0007] Feathering is relatively inconspicuous in a color image area, but is conspicuous in a black image area and deteriorates recording quality. In particular, when the black image is a character, the character is unclear and lacks sharpness, and the quality is poor.

Therefore, in order to obtain high-quality black recording with little feathering and high density, it is necessary to use black ink that has a relatively low penetration rate into plain paper. However, in this case, bleeding of the ink of each color occurs at an adjacent boundary portion between the recording image areas of black and each color, which significantly degrades the quality.

As described above, there has been a conflicting problem in preventing color bleeding of ink between black and each color and in improving color recording quality by simultaneously reducing black feathering.

Therefore, Japanese Patent Laid-Open Publication No. Hei 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. H4-158049 has 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.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art. It is an object of the present invention to record an independent black image area which does not contact a color image area. High density and excellent feathering, and in other areas, excellent recording quality with no ink bleeding between black and each color, that is, high quality black recording and high quality The object is to achieve both high-quality color printing.

Still another object is to improve the fixability of ink and prevent cockling.

[0014]

Accordingly, the present invention provides a color ink jet recording method for forming a desired color image by ejecting black ink and a plurality of color inks different from the black ink onto a recording medium. Determining whether there is a color image adjacent to the black image, and according to the determination result, whether to form the black image with the black ink or to form the black image with the plurality of color inks When the black image is formed with the plurality of color inks, the sum of the ejection amounts of the plurality of color inks with respect to the black image is determined by summing the plurality of color inks for all the pixels of the black image. It is characterized in that printing is performed with the total amount of discharge when the color ink is discharged being reduced. This can prevent bleeding between the black and color images and improve cockling and fixability.

The plurality of color inks are cyan (C), magenta (M), and yellow (Y).

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the drawings. First, the premise of each embodiment will be described.

FIG. 1 is a perspective view of a recording apparatus for carrying out the ink jet recording method of the present invention.

A carriage 101 has a guide shaft 104 on which a recording head 102 and a cartridge guide 103 are mounted.
05 can be scanned.

The recording paper 106 is fed into the main unit by a paper feed roller 107, is sandwiched by a paper feed roller 108 and a pinch roller (not shown), and is fed to the front of the paper feed roller 108 by a paper pressing plate 109 to be printed. You. The ink cartridge is a color ink cartridge 1 containing three colors of yellow (Y), magenta (M), and cyan (C).
10 and 2 of black (Bk) ink cartridges 111
Each type is separately inserted into the cartridge 103 and communicates with the recording head 102.

The yellow, magenta, and cyan inks contained in the color ink cartridge 110 have a high permeation rate to the recording paper so that the ink does not bleed at the boundary between colors when a color image is formed. Used. On the other hand, the black ink accommodated in the black ink cartridge 111 has a relatively high penetration into the recording paper compared to the three types of color inks so that the black image has a high density and a high quality with little ink bleeding. A slower one is used.

FIG. 2 shows the recording head 102. On the front surface of the recording head 102, ejection port groups for yellow, magenta, cyan, and black 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.

FIG. 6 is a view of the recording head 102 as seen from the direction in which the ejection openings can be seen.

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 and electrode wires are formed by a film forming technique on a 201 substrate made of silicon or the like. Further, the discharge port, the ink liquid path, and the common liquid chamber are formed by laminating a partition wall, a top plate, and the like made of resin or glass material on the substrate. 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.

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 a liquid path therein, and the flow path communicates with a common liquid chamber.

There are four yellow, magenta, cyan, and black colors in the distributor, each of which connects a common liquid chamber and a pipe.

From the ejection openings for yellow, magenta, and cyan provided in the recording head 102, about 40 ng
Is ejected from the black (Bk) ejection port by about 80
ng of ink is ejected.

The components of the used ink are as follows. 1. Y (yellow) C.I. I. Direct Yellow 86 3 parts Diethylene glycol 10 parts Isopropyl alcohol 2 parts Urea 5 parts Acetyleneol EH (Kawaken Chemical) 1 part Water balance

2. M (magenta) C.I. I. Assid Red 289 3 parts Diethylene glycol 10 parts Isopropyl alcohol 2 parts Urea 5 parts Acetyleneol EH (Kawaken Chemical) 1 part Water balance

3. C (cyan) C.I. I. Direct Blue 199 3 parts Diethylene glycol 10 parts Isopropyl alcohol 2 parts Urea 5 parts Acetylenol EH (Kawaken Chemical) 1 part Water balance

4. Bk (black) C.I. I. Direct Black 154 3 parts Diethylene glycol 10 parts Isopropyl alcohol 2 parts Urea 5 parts Water balance

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

FIG. 3 is an electric control block diagram of the above-described color ink jet recording apparatus.

Reference numeral 301 denotes a system controller for controlling the entire apparatus, and a storage element (RO) containing a microprocessor and a control program therein.
M), a storage element (RAM) used when the microprocessor performs processing, and the like are arranged. Reference numeral 302 denotes a driver for driving the recording head in the main scanning direction.
Similarly, reference numeral 303 denotes a driver for moving in the sub-scanning direction, and 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.

A host computer 306 is a device for transferring information to be printed to the printing device of the present invention. 307, a reception buffer for temporarily storing data from the host computer;
Data is stored until data is read from the first system controller. Reference numeral 308 denotes a frame memory for expanding data to be printed into image data, which has a memory size necessary for printing. In this embodiment, a frame memory capable of storing one print sheet will be described, but the present invention is not limited to the size of the frame memory.

Reference numeral 309 denotes a storage element for temporarily storing data to be printed, and the storage capacity varies depending on the number of nozzles of the print head. Reference numeral 310 denotes a print control unit for appropriately controlling the print head according to a command from the system controller, and for controlling the ejection speed, the number of print data, and the like. 311 is 312Y, 312M,
A driver for driving the heads 312C and 312Bk is controlled by a signal from the print control unit 310.

FIG. 4 is a flowchart showing the operation of this embodiment.

In STEP 1, the host computer 30
6, the system controller 301 reads data stored in the reception buffer 307. In STEP 2, it is determined whether the read recording data includes black data or only data other than black data. If black is included, go to STEP7; otherwise, go to STEP10.

At STEP 7, attention is paid to the black data, and it is determined whether or not there is color recording data in the image adjacent to the periphery of the black image recording area. Here, the adjacent position is a position “up and / or down and / or left and / or right” with respect to each pixel forming a black image area on the recording medium, and a color image area at this position is formed. It is determined whether there is at least one color recording pixel to perform. The pixel pitch P is about 70.56 μm, and the recording density is 360 dpi. If a color pixel exists at a position adjacent to the black recording pixel, the process proceeds to STEP8; otherwise, the process proceeds to STEP9.

In STEP 8, the black recording pixels are developed in the C, M, and Y data buffers 309YMC for color recording. That is, the black recording pixel is developed into the respective data of C, M, and Y. C instead of Bk ink
Black is expressed by superposing and recording M, Y ink. CMY inks have good penetrability, that is, good fixability, so that recording that does not mix with each of the adjacently recorded colors C, M, and Y, and R, G, and B, which are mixtures thereof, can be performed. . In STEP 9, the black recording pixels are developed in the Bk data buffer 309Bk for black recording.

In STEP 10, each CMY color data is developed in each color data buffer 309CMY.
At this time, if the data already exists in the color buffer 309CMY in the operation of STEP8, a process of setting the logical sum of the existing data and the data added in this step to new data is performed. In STEP 11, it is determined whether there is data to be read from the reception buffer and data to be printed, and whether data for one page has been received. As a result of the determination, if there is no print data, or if there is print data but one page of data has already been received, the process proceeds to STEP12. S otherwise
Return to TEP1. In STEP 12, the recording head 102
Recording operation.

FIG. 9 is an example showing an image in which a black image and a color image are mixed. The image portion A is composed of black enlarged characters of X, Y, and Z and an underline, and is bit image data. Image portion B is code data of black characters. An image portion C is an image having a black graph on a yellow background portion, and is bit image data. Image portion D is an image having black character code data on a cyan background portion.
The image portion E shows a case where a magenta image is present in a part of the background of the black bit image data.

According to the method of this embodiment, the image portion A is only black and has no background color. That is, since the color recording region does not contact the black recording region, black ink is ejected (discharged). The recording is performed by the black ink recording head. The image portion B is also recorded by the black ink recording head similarly to the image portion A. Since the image portion C and the image portion D are all images of other colors around the black image, the black portion is adjacent to the color recording portion, and the color inks, that is, the three color inks of Y, M, and C are used. Recorded using The image portion E is recorded by the black recording head since the color image is not adjacent to the numeral "1" of the black bit image data because the numeral "1" is not adjacent thereto. On the other hand, since the periphery of the numeral “3” is entirely adjacent to the magenta image, it is printed by the color ink recording head. Since the part around the number “2” is adjacent to the magenta image, it is printed by the color ink recording head.

As described above, when the black image recording area is independent and other colors are not recorded in the surrounding area, recording is performed with Bk ink having a high recording density and low feathering. That is, when at least a part of the black image recording area and the other color image areas are in contact with or overlap with each other, the black image recording area is recorded with the C ink, the M ink, and the Y ink, so A high-quality color image in which color bleeding between other colors is prevented is recorded.

In the above example, the recording head is described using a recording method in which bubbles are generated in the ink by an electrothermal transducer and the ink is caused to fly by the action of the bubbles. To fly,
The present invention is also applicable to a so-called piezo-type ink jet recording method.

The method of determining whether or not there is color recording data in a pixel at a position adjacent to the periphery of the black image recording area has been processed by software here, but is not limited to this. Alternatively, the processing may be replaced with hardware. In this case, although the hardware cost is increased, there is an advantage that the processing speed is improved.

Also, in this example, it was determined whether or not another color was recorded around the entire black image recording area. However, the calculation for this determination aims at higher-speed recording processing. The recording method requires a relatively long time. Therefore, as shown in FIG. 5, the same processing is performed only for the character code in the black image recording area, thereby speeding up the arithmetic processing. FIG. 5 is compared with FIG.
Has been added. In this STEP 3, if the black image recording area of interest is a character code, the subsequent processing is performed in the same manner as in FIG. Pixels are developed in C, M, and Y data buffers for color recording.

Even such processing has the advantage that the quality of black characters can be maintained at least as high as before, and high-speed printing is performed.

In this example, in STEP 7 of FIG. 4, the position adjacent to the periphery of the black image recording area is defined as “up, down, left, and left and right” with respect to each pixel forming the black image area on the recording medium. Or right "position. This is an example in which the pitch P is smaller than the pitch P of the recording pixels, and this range needs to be wider depending on the ink used and the recording medium.

An experiment was conducted in which the ink of this example was used to record on various types of plain paper. For the recording pixel pitch P,
First, as X · P around the black image recording area, X = √2
That is, the position of the black pixel of interest “up and / or down and / or left and / or right, and / or upper right and / or upper left and / or lower right and / or upper left” was considered. Next, up to X = 2 was considered. Similarly, X = 2√2
And In this way, the effect of the present invention was satisfactorily exhibited on almost all types of plain paper by performing the processing considering X = 4 ＝ 2.

From the above, the position adjacent to the periphery of the black image recording area of interest is defined as P, where the minimum pixel pitch of recording is P for each pixel forming the black image area on the recording medium.
At least one color print image forming a color image area exists at a print position within X · P,
The case where 4√2 ≧ X ≧ 1 is effective for the present invention.

Alternatively, it is determined whether or not a color (C and / or M and / or Y) image area exists within N (N is 1, 2, 3, 4) pixels adjacent to the black image area of the recording data. According to the result of the discrimination, the recording is switched between the recording with the Bk ink and the recording with the C, M, and Y inks. In the former (existing), the Bk color is recorded with the CMY ink.
In the latter case (not present), recording with Bk ink is effective for the present invention.

In this example, the case where a frame buffer for recording one page is provided is shown. However, the present invention is applicable to a case where a line buffer is provided instead of the frame buffer.

This is because, in step 7 in FIG. 4, as to a position adjacent to the periphery of the black image area, for each pixel forming the black image area on the recording medium, “up and / or down and / or left and / or In addition to this, the problem is solved by assuming that the periphery of the black image recording area is not adjacent to other colors at least within the effective recording area of the line buffer. I do.

As a matter of course, in this case, the STE
In P11, if at least the data buffer for one main scan recording is full, the recording operation is performed and the data in the next reception buffer is read.

In this example, the example of FIG. 6 is shown as the nozzle arrangement of the recording head, but this is not limited to this nozzle arrangement.

For example, as shown in FIG. 7, Ny (Ny is a positive integer) is arranged substantially linearly in the vertical (Y) direction and Nx (Nx is a positive integer) in the horizontal (X) direction. An arrangement having nozzles of each color for a plurality of colors may be used. In the figure, CMY Ny =
4 shows a case where Ny = 8 and Bx = 2 of Bk, and CMY
And Bk are examples of a separable head structure.

FIG. 8A is a schematic view of another printer to which the color ink jet recording method to which the present invention can be applied, wherein 1y is a recording head for yellow ink,
1 m is a recording head for magenta ink, 1 c is a recording head for cyan ink, 1 k is a recording head for black ink, 2 is a carriage on which the 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, 5y, 5
Reference numerals m, 5c, and 5k denote cap members corresponding to the recording heads 1y, 1m, 1c, and 1k, 6 denotes a wiper blade made of a member such as rubber, and 7 denotes a recording sheet that is held opposite to the recording head.

FIG. 8B is a view showing the state of the 4 mounted on the printer.
One of the recording heads is shown, and 64 ejection ports 2 are formed at a density of 360 dpi per inch (360 dpi) in a portion where the recording head faces the recording paper. Each of the discharge ports 10 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. Provided. The ink path corresponding to each of the ejection ports is provided with an electrothermal converter that generates heat energy used for ejecting ink droplets from these ejection ports, and an electrode wiring for supplying power thereto. Have been.

(Embodiment 1) In the previous example, in STEP8,
Bk is described as a process of recording by C + M + Y.
The recording frequency of MY is appropriately reduced, and C and M as a whole are
A new effect can be obtained by expressing black by uniformly recording Y and Y. 80 ng of Bk originally
While CMY is set to 40 ng each, C + M + Y becomes 120 ng, which means that a total of more than 80 ng of ink is ejected. The purpose of this embodiment is to alleviate this.

In STEP 8, the details of the method of developing black recording pixels in the C, M, and Y data buffers 309YMC for color recording will be described.

FIG. 10 shows an overall view of an A4 size recording medium and an enlarged view of the color development pattern in STEP8. Each mark of 〇 △ indicates the minimum recording pixel. The pitch of these marks is about 70.6 in both X and Y directions.
μm. 〇 △ □ indicates Bk in STEP8
When recording pixels are to be expanded to CMY, 〇 indicates a predetermined pattern to be recorded in C + M, △ indicates M + Y, and □ indicates Y + C. Specifically, for example, when the character Z is recorded, the result is as shown in the figure. Although this example is drawn in an enlarged manner, it is a set of several recording pixels. However, in actuality, since it is recorded by a set of a large number of recording pixels, C, M, Y, and Are uniformly dispersed and recorded in Bk color.

Further, as shown in FIG. 11 , this pattern may be a predetermined pattern in which で is recorded in C, △ is recorded in M, and □ is recorded in Y. In this case, there is an advantage that a smaller amount of ink is ejected.

Further, as shown in FIG. 12 , this pattern may be a predetermined pattern in which で is recorded as C, △ as M, □ as Y, and × as C + M + Y. In this case, there is an advantage that a smaller amount of ink is ejected, and the Bk color has a hue closer to the original Bk color.

As described above, instead of setting Bk to C + M + Y,
The recording frequency of MY is appropriately reduced, and C and M as a whole are
And Y are recorded uniformly, thereby making it possible to reduce the total amount of ink ejected onto the recording medium. This means that: Saves ink and lowers running costs.

2. Ink fixability can be improved.

3. When a large amount of ink adheres to a recording medium, the recording medium bends, and becomes a wave-like unevenness, that is, a so-called cockling phenomenon occurs. This cockling phenomenon can be minimized. There are merits such as.

The pattern is not limited to these,
The same effect can be obtained as long as the pattern is such that C, M, and Y are uniform as a whole. (Embodiment 2) In Embodiment 1, CMY is recorded in a pattern in which C, M, and Y are uniform as a whole and CMY is appropriately dispersed. This is when Bk is expanded to CMY,
Bk may be expanded to C + M + Y by using at least one color of CMY as data with an ink ejection amount smaller than usual. Furthermore, in combination with the recording method of Embodiment 1 in which CMY is appropriately dispersed and recorded, at least CMY
The ink ejection amount of one color may be set as data with an ink ejection amount smaller than usual. A similar effect can be obtained for the purpose of reducing the ink ejection amount of the original Bk recording unit.

In order to make the ink ejection amount relatively small, specifically, the energy of a driving pulse for driving the electromechanical transducer or the electrothermal transducer of the recording head at the time of ink ejection is made relatively small. This is done by: That is, this is performed by making the pulse width and / or pulse voltage of the drive pulse relatively small.

Alternatively, in a recording method in which one pixel is usually formed with two ink droplets, the same object can be achieved by using one ink droplet. (Embodiment 3): The embodiment 1 shows an example in which Bk is developed and recorded in CMY in an appropriate predetermined pattern.
Further, by making the user selectable, various recording media can be handled.

Therefore, before transferring the recording data, first, the data for determining the pattern is transferred from the host computer 306 to the system controller 301 through the receiving buffer 307. If the data that determines this pattern is not transferred, for example,
Let the pattern of FIG. 11 be the pattern.

If the recording medium has a good fixing property, B
When a pattern that develops k into C + M + Y is selected, recording is performed in which a Bk color with a higher density can be obtained even in that portion.

[0072] If, Figure 1 if a recording medium having poor fixability as transparency for use in overhead projectors, the Bk C, M, Y are sequentially selected
When the pattern 1 is selected, the entire ink ejection amount is reduced, and recording with better fixability is achieved. Further, the recording medium having the intermediate characteristic has, for example, Bk as C + M, M + Y,
The pattern of FIG. 10 in which Y + C are selected in order is selected.

As described above, by enabling the user to select a pattern for developing Bk into CMY, high-quality recording on a wider range of recording media becomes possible. (Embodiment 4) In the embodiment 2, the user sets Bk to CMY.
Although the pattern to be developed can be selected, this may be automatically performed by providing a means for determining the recording medium.

Specifically, when the recording medium is a transparency used in an overhead projector, the recording medium is determined by means disclosed in, for example, JP-A-2-227271. In this case, since the recording medium has poor fixability, the pattern in FIG. 12 in which C, M, and Y are selected in order for Bk is selected, and the overall ink ejection amount is reduced, and recording with better fixability is performed. Is automatically obtained. Fifth Embodiment In the first embodiment, an example in which the Bk data is developed into predetermined patterns of C, M, and Y in STEP8 has been described, but the effect of the present invention is limited to the predetermined pattern. It is not something you can get.

The Bk data includes at least Non (not recorded), C, M, Y, C + M, M + Y, Y + C, C +
The pattern may be a pattern determined at random from among eight types of M + Y. This is STEP8, Bk
When the data is expanded, it is realized by using a random number generation routine of the system controller 301 and expanding the data with values selected from the above eight types.

The present invention provides an excellent effect particularly in a recording head and a recording apparatus of a type utilizing thermal energy among ink jet recording types.

The typical configuration and principle are described in, for example, US Pat. Nos. 4,723,129 and 4,740.
It is preferable to use the basic principle disclosed in the specification of Japanese Patent No. 796. This method is a so-called on-demand type,
Although it can be applied to any type of continuous type, in particular, in the case of the on-demand type, it can be applied to a sheet holding liquid (ink) or an electrothermal converter arranged corresponding to the liquid path. By applying at least one drive signal corresponding to the recording information and giving a rapid temperature rise exceeding nucleate boiling, heat energy is generated in the electrothermal transducer, and the film is heated on the heat-acting surface of the recording head. As a result, bubbles in the liquid (ink) can be formed in one-to-one correspondence with the drive signal, which is effective. By discharging the liquid (ink) through the discharge opening by the growth and contraction of the bubble,
Form at least one drop. 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. Examples of the drive signal in the form of a pulse include U.S. Pat. Nos. 4,463,359 and 4,345.
No. 262 are suitable. Further, if the conditions described in US Pat. No. 4,313,124 of the invention relating to the temperature rise rate of the heat acting surface are adopted, more excellent recording can be performed.

As the configuration of the recording head, in addition to the combination configuration (a linear liquid flow path or a right-angled liquid flow path) of a discharge port, a liquid path, and an electrothermal converter as disclosed in the above-mentioned respective specifications, U.S. Pat. No. 4,558,333 and U.S. Pat. No. 4,558,333 which disclose a configuration in which a heat acting portion is arranged in a bending region.
A configuration using the specification of Japanese Patent No. 459600 is also included in the present invention. In addition, Japanese Unexamined Patent Publication (Kokai) No. 123670/1984 discloses a configuration in which a common slit is used as a discharge portion of an electrothermal converter for a plurality of electrothermal converters, and an aperture for absorbing pressure waves of thermal energy. The present invention is also effective as a configuration based on Japanese Patent Application Laid-Open No. 59-138461, which discloses a configuration corresponding to a discharge unit.

[0079]

As described above, according to the present invention, when recording an independent black image area which does not come into contact with a color image area, the density of the black image area is high, and excellent feathering is reduced. In addition to the high recording quality, the other areas have excellent recording quality with no ink bleeding between black and each color, that is, both high-quality black recording and high-quality color recording are compatible.

Further, depending on the pattern that can be selected by the user or the recording medium, it is possible to automatically record Bk in CMY with an appropriate pattern, thereby reducing the fixing property and cockling and reducing the amount of ink used. It is possible to perform high-quality recording with few images.

[Brief description of the drawings]

FIG. 1 is a perspective view of an inkjet recording apparatus to which the present invention can be applied.

FIG. 2 is a head mechanism diagram of an ink jet recording apparatus to which the present invention can be applied.

FIG. 3 is a block diagram of a control circuit of an inkjet printing apparatus to which the present invention can be applied.

FIG. 4 is a flowchart illustrating the operation of the embodiment.

FIG. 5 is a flowchart illustrating another operation flow of the embodiment.

FIG. 6 is a front view of the recording head according to the embodiment.

FIG. 7 is a front view of another recording head according to the embodiment.

FIG. 8 is a diagram showing an ink jet recording apparatus applicable to the present invention.

FIG. 9 is an example of an image for explaining the present invention.

FIG. 10 is a pattern for recording Bk in CMY according to the first embodiment.

FIG. 11 is another pattern for recording Bk in CMY according to the first embodiment.

FIG. 12 shows yet another pattern for recording Bk in CMY according to the first embodiment.

[Explanation of symbols]

102 Recording head 110 Color ink cartridge 111 Black ink cartridge 301 System controller 302 Carriage motor driver 303 Paper feed motor driver 304 Carriage motor 305 Paper feed motor 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 Recording head for each color

Claims (11)

(57) [Claims] 1. A color ink jet recording method for forming a desired color image by discharging a black ink and a plurality of color inks different from the black ink onto a recording medium, wherein the color image is formed adjacent to the black image. It is determined whether or not the black image exists, and according to the determination result, it is determined whether the black image is formed with the black ink or the plurality of color inks, and When forming with the color ink of the color, the discharge of the plurality of color inks to the black image is performed.
The output sum is calculated for each pixel of the black image.
Of the ejection amount when the plurality of color inks are ejected by
A color ink jet recording method characterized in that recording is performed with a value smaller than the total sum . 2. The color ink jet recording method according to claim 1, wherein the plurality of color inks are cyan (C), magenta (M), and yellow (Y).
Law . 3. The color inkjet recording according to claim 2, wherein at the time of recording a black image, recording is performed using at least two inks of C, M, and Y for at least one pixel of black. Method. 4. The color ink jet recording according to claim 2, wherein at the time of black image recording, at least one of C, M, and Y ink ejection amounts is reduced for one black pixel. Method. 5. When a black image is recorded, a black recording area
3. The color ink jet recording method according to claim 2, wherein the recording is performed in a specific pattern among C, M, and Y by selectively using three or less inks. 6. The color ink jet recording method according to claim 5, wherein the specific pattern is a pattern in which C, M, and Y are uniformly dispersed as a whole. 7. The specific pattern is C + M, M +
6. The color ink jet recording method according to claim 5, wherein a pattern in which Y and Y + C are alternately repeated. 8. The method according to claim 5, wherein the specific pattern is a pattern in which C, M, and Y are alternately repeated. 9. The specific pattern is at least N
on (not recorded), C, M, Y, C + M, M + Y, Y
6. The color ink jet recording method according to claim 5, wherein the pattern is a pattern determined at random from eight types of + C and C + M + Y. 10. The color ink jet recording method according to claim 5, wherein an optimum pattern is selected as the specific pattern according to a recording medium. 11. The color inkjet recording method according to claim 1, wherein the ink is ejected by thermal energy.