JPH07117331A - Color ink jet recording method - Google Patents

Abstract

PURPOSE:To raise both qualities of black recording and color recording by a method wherein a ratio in recording between a black image with black ink in a black image area and a black image with mixed color of color ink of a plurality of colors is varied according to frequency in recording of a color image. CONSTITUTION:At Step-1, a data is transferred from a host computer, and the data stored in a receiving buffer is read with a system controller. The data read at Step-1 is expanded into a data corresponding to each color to be stored in each frame memory of C, M, Y, Bk at Step-2. At Step-3, an area to be recorded on a recording medium is divided into a specific area M, and duty of color recording in the area M is calculated. At Step-4, how many black recording pixels are added to PCBk to prepare it from the black data in the specific area is determined according to the duty of a color dot. At Step-5 mixing process of the black dot prepared with Bk ink and a mixed color dot prepared with color ink is carried out according to the determination.

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 for recording a color image clearly and with high density in a recording method of an ink jet recording apparatus for recording by ejecting ink from a recording head. Is yellow (hereinafter, Y), magenta (hereinafter, M), cyan (hereinafter, C), or green (hereinafter, G), red (hereinafter, R), bull (hereinafter, B) The present invention relates to a color inkjet recording method using color inks such as, and black (hereinafter, Bk) ink.

[0002]

2. Description of the Related Art Ink jet recording methods are used in printers, copiers, facsimiles and the like because of their low noise, low running cost, easy size reduction and color reduction.

In the conventional ink jet recording method, it was necessary to use a special paper (coated paper) having an ink absorbing layer in order to obtain a color image of high color development without ink bleeding. As a result of improvements, methods have been put into practical use that allow printing on "plain paper" that is used in large quantities in printers and copiers. However, "plain paper"
At present, the printing quality on the printer is still at an insufficient level. The most important factor is compatibility between ink bleeding between colors and black recording quality (particularly black character recording quality).

In recent years, in order to obtain a color image on a plain paper which prevents bleeding by an ink jet recording method, a quick-drying ink having a high penetration speed to the plain paper has been developed.

Generally, the color ink jet recording method uses three color inks of cyan, magenta and yellow, and further, four color inks including black are used for color recording.

When the above-described ink having good permeability is used, a high-quality image without ink bleeding between the colors is obtained, but the density is low as a whole, and the periphery of the recording image area of each color is The ink slightly bleeds along the fibers of the paper (feathering) and lacks sharpness.

Feathering is relatively difficult to notice in a color image area, but is easily noticeable in a black image area, resulting in deterioration of recording quality. In particular, when the black image is a character, it becomes an indistinct character lacking a sharp, and the deterioration of the quality is very noticeable.

Therefore, in order to obtain a high-quality black record with less feathering and high density, it is necessary to use an ink of a type having a relatively slow penetration speed into plain paper as a black ink used for a black image. .

However, when the color ink is an ink which has a slow penetration rate to the paper and the black ink which forms a black image is an ink having a slow penetration rate, the recording image area of each color of black and color is used. Inadequate ink bleeding occurs at the adjacent boundary portion, and the quality is remarkably impaired.

As described above, the improvement of color recording quality by simultaneously preventing the ink bleeding between black and each color and reducing the feathering of black has been a contradictory issue.

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

Further, in Japanese Patent Laid-Open No. 4-158049 (Fuji Xerox Co., Ltd.), a multi-color head for color recording and a head for character recording are provided, and a multi-color head and character recording head are provided based on a recorded image. A method of recording by switching between the head and the head has 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 size of the device are inevitable.

At present, there has been considered a method of forming a black area along the boundary area between black and color by overlapping color inks to prevent bleeding at the boundary area between black and color. Here, the black formed by using the color inks is represented by P
It is referred to as CBk (Process Color Bk). In principle, black can be obtained by superimposing (mixing) three colors of Y, M, and C, but a black image formed by mixing color inks in this way is Poor color development.

[0014]

In the above method of replacing the black area at the boundary with PCBk, the simplest method is to replace all the black data with PCBK data of Y, M, and C. is there.

PCBk composed of only Y, M and C is
Actually, it is quite different from Bk ink in terms of hue, and only the boundary portion is bordered, but since it is ink with good permeability, there is no unreasonable bleeding at the boundary portion with the color. Therefore, by using PCBk containing Bk ink in a certain ratio to adjust the tint, it is possible to make the hue slightly deviate, but on the other hand, it becomes easy to bleed at the boundary with the color.

The bleeding and edging at the boundary depends on the black data at the boundary and the duty of the color image around the black data, and is recognized by the user as a harmful effect on the image.

The present invention has been made in order to solve the above-mentioned problems, and when recording a black image area adjacent to a color image area, the color tone is not changed and bleeding also occurs. A means to suppress is needed. Furthermore, not only is the recording quality excellent without ink bleeding between black and color-each color, but also excellent recording quality with less feathering in the black image area, that is, high-quality black recording and high-quality recording. It is to realize both color recording.

[0018]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above object, and it is a black ink and a plurality of colors of color having different recording medium penetration characteristics from the black ink.
Using ink and the desired color according to the recording data.
In a color inkjet recording method for recording an image on a recording medium, a step of detecting a recording frequency of the color image in a specific area on a recording position of the recording medium,
Changing the ratio of recording of a black image with the black ink and a black image with a mixture of the color inks of a plurality of colors in a black image area according to the recording frequency of the color image. .

Further, the present invention is characterized in that the higher the frequency of color recording in the specific area, the higher the ratio of black dots due to color mixing of a plurality of color inks.

Further, according to the present invention, the ratio of the black ink and the color inks of a plurality of colors in the black image area in a certain specific area is changed according to the recording frequency of the color image in the plurality of specific areas. Is characterized by.

Further, in order to achieve the above object, the present invention uses a black ink and a plurality of color inks having different recording medium penetration characteristics from the black ink to record a recording data.
In a color inkjet recording method for recording a desired color image on a recording medium in accordance with the color image, a step of determining a black image area close to the color image, and a step of determining a black image area around the black image area close to the color image A step of calculating a color recording frequency, and a step of determining a ratio of a black dot by the black ink and a black dot by a color mixture of the plurality of colors of color ink in the black image area according to the calculation result,
It is characterized by consisting of.

Further, the ratio of the black dots by the black ink in the black image area and the black dots by the color mixture of the color inks of a plurality of colors is determined by a mask pattern for recording the black image area. .

The present invention provides an ink jet recording method capable of reducing bleeding at the boundary between a black image and a color image and recording a high-quality image with high density and no feathering even in the black image. It is provided.

[0024]

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

(Embodiment 1) FIG. 1 is a perspective view of a recording apparatus for carrying out the ink jet recording method of the present invention.
The carriage 101 has a recording head 102 and a cartridge guide 103 mounted thereon, and can scan on guide shafts 104 and 105 by a driving device (not shown).

The recording paper 106 is fed into the main body by a paper feed roller 107, sandwiched by a paper feed roller 108, a pinch roller (not shown), and a paper pressing plate 109, and is sent to the entire surface of the paper feed roller 108 for printing. It Two types of ink cartridges, a color ink cartridge 110 containing three colors of yellow, magenta, and cyan, and a black ink cartridge 111 are separately inserted into the cartridge 103 and communicate with the recording head 102.

The yellow, magenta, and cyan inks stored in the color ink cartridge 110 penetrate into the recording paper so that ink bleeding does not occur at color boundaries when forming a color image. The fast one is used. On the other hand, the black ink stored in the black ink cartridge 111 is relatively high in quality as compared with the above three types of color ink so that the black image has high density and high quality with less ink bleeding. A material having a slow penetration speed into the recording paper is used.

FIG. 2 shows the recording head 102. Yellow, magenta, cyan, and black ejection port groups are arranged in a straight line on the front surface of the recording head 102. Each group has 24 discharge ports for yellow, magenta, and cyan, and 64 discharge ports for black, and the intervals between colors are equal to or greater than the nozzle pitch.

Each of these ejection ports is provided with an ink liquid passage communicating with the ejection port, and a common liquid for supplying ink to these liquid passages is provided behind the portion where the ink liquid passage is provided. A room is provided. In the ink liquid path corresponding to each of the ejection ports, an electrothermal converter (ejection heater) that generates thermal energy used for ejecting ink droplets from these ejection ports, and an electrode for supplying electric power to the electrothermal converter Wiring is provided. The electrothermal converter and the electrode wiring as the discharge heater are formed on the 201 substrate made of silicon or the like by the film forming technique. Further, the ejection port, the ink liquid path, and the common liquid chamber are formed by stacking a partition wall made of resin, a glass material, a top plate, etc. on the substrate. Further on the rear side, a drive circuit for driving the electrothermal converter based on a recording signal is provided in the form of a printed circuit board.

Alternatively, instead of using the above-mentioned glass material, a grooved top plate (orifice plate) provided with partition walls and a common liquid chamber for partitioning a plurality of ink channels, and the substrate are bonded together. You may make it the structure formed. The grooved top plate is integrally molded, and polysulfone is preferable as the integrally molded material, but other molding resin materials may be used.

The silicon substrate and the printed circuit board 202 are the same aluminum plate 203 and the pipe 20 protruding in parallel.
Reference numerals 4 to 207 project from a plastic member 208 called a distributor that extends in a direction perpendicular to the silicon substrate, and further communicates with a flow path inside thereof.
The flow path communicates with the common liquid chamber.

There are four channels in the distributor for yellow, magenta, cyan and black.
Each common liquid chamber is connected to a pipe.

In this embodiment, the color ink and the Bk ink can be independently exchanged for ink tanks. This uses a disposable type recording head in which the ink tank and the print head are integrated. Is also good.

Yellow provided on the recording head 102
40 ng from the discharge ports for black, magenta and cyan
Ink is about 80n from the black discharge port.
g of ink is ejected.

An example of the components of the used ink is shown below. 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 Co.) 1 part Water balance 2. M (magenta) C.I. I Acid Red 289 3 parts Diethylene glycol 10 parts Isopropyl alcohol 2 parts Urea 5 parts Acetyleneol EH (Kawaken Chemical Co.) 1 part Water balance 3. C (cyan) C.I. 3. I Direct Bull-199 3 parts Diethylene glycol 10 parts Isopropyl alcohol 2 parts Urea 5 parts Acetyleneol EH (Kawaken Chemical Co.) 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 an improved permeability with respect to Bk by adding 1% of acetylenol EH. Other than this, the adducts include other surfactants, alcohols and the like. The ink composition is not particularly limited to these.

FIG. 3 is a block diagram of electrical control of the above-mentioned color ink jet recording apparatus.

Reference numeral 301 denotes a system controller for controlling the entire apparatus, and a storage element (ROM) in which a control program including a microprocessor is stored inside.
A memory element (RAM) and the like used when the microprocessor performs processing are arranged. Reference numeral 302 is a driver for driving the recording head in the main scanning direction, and similarly 303 is a driver for moving the paper in the sub scanning direction. Motors 304 and 305 correspond to the driver, and 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. Reference numeral 307 denotes a reception buffer for temporarily storing data from the host computer 306, which stores the data until the data is read from the system controller 301. A frame memory 308 expands data to be printed into image data, and has a memory size 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 this.

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

FIG. 4 is a flow chart for explaining an embodiment of the present invention.

First, in step 1, data is transferred from the host computer 306, and the reception buffer 307
Data stored in the system controller 301
Read out. In step 2, the data read in step 1 is expanded and stored in each of C, M, Y, and Bk frame memories 308 corresponding to each color.
In the next step 3, the area recorded on the recording medium is divided into specific areas M, and the duty of color recording in the area M is calculated. Specifically, as shown in FIG. 5, the recording data for one A4 size sheet stored in the frame memory is divided into a specific area M consisting of 16 pixels in total, which is composed of 4 dots in each of the vertical and horizontal directions. Specific area M
The number of C, M, and Y recording pixels in the inside is counted, and the duty of the color dot is calculated by the number of color pixels / (16-the number of black pixels). In step 4, it is determined according to the duty of the color dots how much black data in the specific area should be PCBk to which black recording pixels are added. An example is shown below. In the example below, PCB according to color duty
The pattern of k is shown, and an example of the pattern will be described later.

Color duty <25% BK as it is 25% ≦ Color duty <50% PCBk1 50% ≦ Color duty <75% PCBk2 75% ≦ Color duty PCBk3

In accordance with the PCBk determined in step 4, in step 5, a mixing process of black dots made of Bk ink and mixed color dots made of color ink is performed. For example,
If the color duty is less than 25%, all black pixels are black dots made with Bk ink, and the color duty is 25% or more 5
When it is less than 0%, a process of converting to color data corresponding to each by masking PCBk1 as shown in FIG. 6 is performed. Similarly, when the color duty is 50% or more and less than 75%, the mask of PCBk2 shown in FIG. 6 is used, and when the color duty is 75% or more, the mask of PCBk3 of FIG. 6 is used. Next, step6 is BK, C, M,
The data of each color of Y is expanded in the buffer for each color.

At step 7, the recording operation is performed as in the conventional case, and then a series of operations is performed.

As a result, as the color duty around the black pixel increases, the black pixel is formed of color ink in the PC.
The ratio is increased to Bk, and the lower the color duty around the black pixel is, the more the black pixel is printed with the Bk ink as it is. That is, when the color duty with a large amount of bleeding is large, the bleeding between the black image and the color image is reduced by reducing the proportion of the Bk ink, and when the color duty with a small amount of bleeding is low, the Bk ink is used as much as possible to obtain the tint. This is a process that reduces the discomfort caused by the difference.

This processing is performed by the system controller 301.
It is processed like a software by the program inside. This processing is not limited to this, and may be realized by an electric circuit that is hardware, for example, in order to perform processing at higher speed.

In this embodiment, the pixel pitch P is about 7
The recording density is 0.56 μm and the recording density is 360 dpi.
Therefore, the number of recording pixels for recording A4 full size is about 2600 in the horizontal direction and about 3600 in the vertical direction. The number of specific areas M is about 65 in the horizontal direction because the area is 4 × 4 pixels.
0 is about 900 in the vertical direction.

Although the ratio of Bk ink pixels of PCBk is changed by the threshold value of 25% increments in color duty, the present invention is not limited to this. Further, although the case where the frame buffer for recording one page is provided is shown here, the present invention is applicable even when the line buffer is provided instead of the frame buffer.

As described above, according to the present invention, the duty of the surrounding color of the color image adjacent portion of the black image is discriminated, and the BK ink in the PCBk formed by the color inks of a plurality of colors is discriminated according to the discrimination result. By determining the proportion of
There is no bleeding, and it is possible to make the color tone change due to PCBk inconspicuous as much as possible. As a result, excellent recording quality with less feathering in the black image area can be realized, and excellent recording quality without ink bleeding between black and color-colors can be achieved, resulting in high-quality black recording and high-quality recording. It is possible to achieve color recording compatibility.

(Second Embodiment) In the first embodiment, the case where the entire recording area is divided into the specific areas M and processed is shown. However, when the specific region M divided as shown in FIG. 7 is exactly divided at the boundary between the black pixel and the color pixel, only the black pixel is processed as black data of Bk ink because the color duty is low. . In such a case, it is possible to avoid it by processing the information around the specific area M as well.

Specifically, as an example, as shown in FIG.
By providing a wider specific area (nine specific areas M),
The PCBk in the particular area M of interest is determined according to the color duty in this wide area. The calculation processing time is longer than that in the first embodiment, but the processing is more reliable.

As a result, since the determination is made in consideration of the surrounding conditions, an appropriate PCBk recording pattern is determined even in recording when a recording image as shown in FIG. 7 is included, there is no bleeding, and the color tone due to PCBk It is possible to make changes as inconspicuous as possible.

(Third Embodiment) FIG. 9 is a flow chart for explaining the third embodiment. Step 1 is the reception buffer 30
Data stored in the system controller 30
1 is the first step to process, data is transferred from the host computer 306 and the stored data is read. Next, in step 2, the read data is expanded and stored in each of C, M, Y, and Bk frame memories 308 corresponding to each color. Then, in step 8, the boundary between the color image data and the black image data is detected. s
At step 9, attention is paid to the black data, and it is determined whether or not the black data is the boundary with the color. If it is the boundary with the color, the process proceeds to step 10, and if it is not the boundary with the color, the process proceeds to step 13. In step 10, the boundary pixel is used as the pixel of interest to calculate the color duty within the 7 × 7 specific area, and in step 11, the PCBk of the pixel of interest is determined according to the duty, and that information is temporarily stored in the buffer. In the next step 12, P that is provided in advance according to PCBk determined in the same manner as in the first embodiment.
By applying a CBk mask, a mixing process of black dots made of Bk ink and mixed color dots made of color ink is performed.

In step 13, the data of each color of Bk, C, M, Y is expanded in the buffer for each color, and step 1
In 4, the recording operation is performed as in the conventional case, and then the series of operations is performed.

Further, referring to FIG. 10, s in this embodiment
The boundary detection sequence for detecting the black image area in contact with the color image area of step 3 and the black dot data (P in which Bk ink and color ink are mixed in step 7)
The processing sequence of CBk) will be described.

First, in step 15, of the image original data (Bk, Y, M, C) of each color to be recorded,
OR the Y, M, and C data. At the next step 16, the OR data of Y, M, and C is temporarily stored in the buffer as color data, and at step 17, the bold data in which the color data is expanded by 4 bits vertically and horizontally is generated and stored in the buffer. To do. This work is performed using drag shift, which is a function of the gate array. The OR is performed with the original data while shifting the address, and the original data is bolded in the shifted direction. By performing this in 4 directions of up, down, left and right, 4 bits at a time, 4 bits of up, down, left and right, bolded color data is generated.

At step 18, the color bold data and the Bk original data are ANDed and extracted as Bk data to be converted into PCBk at the boundary.

At the next step 19, the extracted data to be converted is ANDed with the PCBk mask pattern (conversion mask) set for each color to obtain the PCB.
Each newly generated data is generated to generate k. Next, in step 20, the newly generated PCBk data of each color and the original data are ORed to obtain final image data. Also, since PCBk is originally generated from Bk data,
It is necessary to remove the data replaced by PCBk from the original data. In step 21, the PCBk data is inverted and ANDed with the original Bk data.
Is taken, the PCBk data is removed from the original data, and further ORed with the Bk PCBk data to obtain the final Bk image data.

In this sequence, the width replaced by PCBk can be controlled by changing the bold amount of color data. Further, by performing this sequence in multiple stages, it is possible to detect the directionality at the boundary between the black image area and the color image area. Furthermore, by detecting the boundary between each color and Bk separately, it is possible to set an appropriate PCBk for each color.

With the above configuration, an appropriate PCBk can be set, there is no bleeding, and the change in color tone due to PCBk can be made as inconspicuous as possible.

Further, in the present embodiment, since the boundary portion between color and black, which is likely to cause bleeding, is detected and processed in advance, the original black data can be more efficiently converted into PCBk data.

In each of the above-described embodiments, image determination /
The control processing means such as the judgment processing, the image expansion processing, the replacement processing, and the like are collectively controlled by the control unit in the recording apparatus based on the data received from the host computer, but the present invention is not limited to this. It is not limited.

For example, it is possible to extend all of the above control / processing means to a system in which an external device is executed by a printer driver or the like to receive the actual recording data after the pixel replacement processing is completed. Often the external device connected to the recording device is a host computer,
The host computer is superior in the processing capacity and RAM capacity of the CPU for performing the above processing.

The host computer may share the image determination processing, and the printer may share the image development processing.

Further, in the embodiment of the present invention, the recording apparatus provided with the head in which the ejection openings for ejecting the inks of a plurality of colors are arranged in a vertical line has been described as an example, but the present invention is not limited to this. Absent. For example, in a recording apparatus of a type in which a plurality of recording heads of the same size for ejecting inks of different colors are laterally arranged and mounted on a carriage, and the carriage is scanned in the direction in which the heads are arranged. It is applicable. In this case, since the recording heads of the same size are arranged in parallel, the recording time can be shortened.

In this embodiment, as the recording head, a so-called bubble jet recording method is used in which bubbles are generated in the ink by the electrothermal converter and the ink is ejected by the action of the bubbles. Needless to say, the present invention can be applied to a so-called piezo inkjet recording system in which ink is ejected by the body.

The present invention provides excellent effects particularly in a recording apparatus using an inkjet recording head for recording by forming flying liquids by utilizing thermal energy among the inkjet recording systems.

Regarding its typical structure and principle, see, for example, US Pat. Nos. 4,723,129 and 4740.
What is done using the basic principles disclosed in 796 is preferred. This method is a so-called on-demand type,
It can be applied to any of the continuous type, but especially in the case of the on-demand type, it can be applied to the sheet holding the liquid (ink) or the electrothermal converter arranged corresponding to the liquid path. By applying at least one drive signal that corresponds to the recorded information and gives a rapid temperature rise exceeding nucleate boiling, heat energy is generated in the electrothermal converter, and film boiling occurs on the heat acting surface of the recording head. Liquid (ink) that is generated and eventually responds to this drive signal as a single unit
It is effective because bubbles can be formed inside. The liquid (ink) is ejected through the ejection openings by the growth and contraction of the bubbles to form at least one droplet. It is more preferable to make this drive signal into a pulse shape because bubbles can be immediately and appropriately grown and contracted, so that liquid (ink) ejection with excellent responsiveness can be achieved. As the pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. If the conditions described in US Pat. No. 4,313,124 of the invention relating to the rate of temperature rise on the heat acting surface are adopted, more excellent recording can be performed.

As the constitution of the recording head, other than the combination constitution of the ejection port, the liquid passage, and the electrothermal converter (the linear liquid passage or the right-angled liquid passage) as disclosed in the above-mentioned respective specifications. U.S. Pat. No. 4,558,333 and U.S. Pat. No. 44, which disclose a configuration in which a heat acting portion is arranged in a bending region.
The structure using the specification of No. 59600 is also included in the present invention. In addition, Japanese Unexamined Patent Publication No. 59-123670 discloses a configuration in which a common slit is used as a discharge portion of the electrothermal converter for a plurality of electrothermal converters, and an opening for absorbing a pressure wave of thermal energy is provided. The effect of the present invention is effective even if the configuration corresponding to the ejection portion is disclosed in JP-A-59-138461. That is, according to the present invention, recording can be surely 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 which can be recorded by the recording apparatus. 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 recording head integrally formed.

In addition, even in the case of the serial type as in the above example, the recording head fixed to the main body of the apparatus, or the electrical connection to the main body of the apparatus or the ink from the main body of the apparatus by being attached to the main body of the apparatus. 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 integrally provided in the recording head itself is used.

Further, as the constitution of the recording apparatus of the present invention, it is preferable to add ejection recovery means of the recording head, preliminary auxiliary means and the like because the effects of the present invention can be further stabilized. Specifically, heating is performed by using a capping unit, a cleaning unit, a pressure or suction unit for the recording head, an electrothermal converter or a heating element other than this, or a combination thereof. Examples thereof include a preliminary heating unit for performing the discharge and a preliminary discharge unit for performing discharge different from the recording.

Regarding the type and number of recording heads to be mounted, two or more recording heads may be provided corresponding to a plurality of inks having different recording colors and densities. That is, for example, the recording mode of the recording apparatus is not limited to the recording mode of only the mainstream color such as black, but it may be either the recording head is integrally formed or a plurality of combinations may be used. The present invention is also extremely effective for an apparatus provided with at least one of full-color recording modes by color mixing.

In addition, in the above-described embodiments of the present invention, the ink is described as a liquid, but an ink that solidifies at room temperature or lower and that softens or liquefies at room temperature may be used. Or, in the inkjet system, it is common to adjust the temperature of the ink itself within the range of 30 ° C. or higher and 70 ° C. or lower to control the temperature so that the viscosity of the ink is within the stable ejection range. Sometimes, a liquid ink may be used. In addition, the temperature rise due to thermal energy is positively prevented by using it as the energy of the state change of the ink from the solid state to the liquid state, or in order to prevent the evaporation of the ink, it is solidified and heated in the standing state. You may use the ink liquefied by. In any case, by applying thermal energy such as ink that is liquefied by applying thermal energy according to the recording signal and liquid ink is ejected, or that begins to solidify when it reaches the recording medium. The present invention can be applied to the case where an ink having a property of being liquefied for the first time is used. In this case, the ink is
JP-A-54-56847 or JP-A-60-7
As described in Japanese Patent No. 1260, it may be configured to face the electrothermal converter in a state of being held as a liquid or a solid in the concave portion or the 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, as a form of the ink jet recording apparatus of the present invention, besides the one used as an image output terminal of an information processing apparatus such as a computer, a copying apparatus combined with a reader or the like, and a facsimile apparatus having a transmitting / receiving function. It may be a form or the like.

[0077]

According to the present invention, when the PCBk replacement is performed at the boundary between the color image area and the black image area, the appropriate PCBk replacement is selected according to the duty of the color image. There is no PC
It is possible to make the color tone change due to Bk as inconspicuous as possible. This makes it possible to achieve excellent recording quality with less feathering in the black image area, and it is possible to achieve excellent recording quality without ink bleeding between black and color-colors,
It is possible to achieve both high-quality black recording and high-quality color recording.

[Brief description of drawings]

FIG. 1 shows 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 inkjet recording apparatus to which the present invention can be applied.

FIG. 3 is a block diagram of an inkjet recording apparatus control circuit to which the present invention is applicable.

FIG. 4 is a diagram showing an operation flow of the first embodiment.

FIG. 5 is a diagram showing a relationship between a recording area and a specific area in the first embodiment.

FIG. 6 is a diagram showing a pattern example of a PCBk mask used at the time of PCBk replacement.

FIG. 7 is a diagram showing an example of a relationship between original black recording pixels and color recording pixels in a specific area.

FIG. 8 is a diagram showing a relationship between a recording area and a specific area in the second embodiment.

FIG. 9 is a diagram showing an operation flow of the third embodiment.

FIG. 10 is an explanatory diagram of a boundary detection sequence and a PCBk replacement sequence.

[Explanation of symbols]

101 Carriage 102 Recording Head 103 Cartridge 104 Guide Shaft 105 Guide Shaft 106 Recording Paper 107 Paper Feed Roller 108 Paper Feed Roller 109 Paper Pressing Plate 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 Reception 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 for each color head

Claims (6)

[Claims] 1. A desired color image is formed on a recording medium according to recording data by using black ink and color inks of a plurality of colors having different recording medium penetration characteristics from the black ink. In the color inkjet recording method for recording on a recording medium, a color in a specific area on a recording position of the recording medium is recorded.
Detecting the recording frequency of the image, and changing the ratio of recording the black image by mixing the black image with the black ink and the color inks of a plurality of colors in the black image area according to the recording frequency of the color image. A color inkjet recording method comprising the steps of: 2. The color ink jet recording method according to claim 1, wherein the higher the frequency of color recording in the specific area, the higher the ratio of black dots due to color mixing of a plurality of color inks. 3. The ratio of the black ink and the color ink of the plurality of colors in a black image area in a certain specific area is changed according to the recording frequency of color images in the plurality of specific areas. The color inkjet recording method according to claim 1. 4. A desired color image is formed on a recording medium according to recording data by using black ink and a plurality of color inks having different recording medium penetration characteristics from the black ink. In the color inkjet recording method for recording in step 1, a step of determining a black image area close to a color image, a step of calculating a color recording frequency around a black image area close to the color image, and And a step of determining a ratio of black dots formed by the black ink and black dots formed by mixing the color inks of the plurality of colors in the black image area. 5. A ratio of a black dot formed by the black ink and a black dot formed by mixing color inks of the plurality of colors in the black image area is determined by a mask pattern for recording the black image area. The inkjet recording method according to claim 1. 6. The ink jet recording method according to claim 1, wherein the ink is ejected by a pressure based on a state change of the ink due to heat.