JPH06135014A - Ink jet reocrding method - Google Patents

Abstract

PURPOSE:To obtain a high quality image in which smear of ink is lessened at the border part of black image and color image. CONSTITUTION:A delivery part group 10d for delivering black ink and delivery part groups 10a, b, c are arranged such that they do not overlap each other. When a black image to be printed with black ink is contiguous to a color image to be printed with a color ink, the black image is formed through scanning as shown at (a) whereas the color image is formed through scanning as shown at (c) and only lower half delivery part in black ink delivery part group is used so that both scannings are not performed continuously.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording method for recording a multicolor image by using a recording head having a plurality of color inks and a plurality of nozzles corresponding to the respective colors. In particular, the present invention relates to an inkjet recording method using a recording head in which the number of nozzles of a specific color is larger than the number of nozzles of other colors.

[0002]

2. Description of the Related Art Conventionally, a method for obtaining a color image using four color inks of yellow (Y), magenta (M), cyan (C) and black (Bk) has been widely known, and printers have been widely known. And applied to copiers.

As one method for that purpose, an ink jet recording method using four ink jet recording heads corresponding to each color so that the four color inks can be ejected independently has been put into practical use. In this method, since the print heads are independent for each color, the print heads can be shared if the ink ejection amounts for each color are equal,
Further, there is an advantage that the method of driving each recording head is simple.

[0004]

However, since four recording heads are mounted, there are drawbacks that it is unsuitable for downsizing the apparatus which is a recent tendency, the cost is high, and the assembly is not easy.

On the other hand, since four recording heads are used, it is suitable for speeding up, especially when printing on recording paper such as plain paper on which ink fixing is slow, ink bleeding easily occurs between colors, resulting in remarkable image formation. Has the drawback of degrading the quality of.

Therefore, a recording head has been proposed as shown in FIG. 1 in which nozzles (ejection portions) of respective colors for ejecting yellow, magenta, cyan, and black inks do not overlap in the scanning direction. There is. If this recording head is used, only one recording head is required to obtain a multicolor image, and it is very suitable for an inexpensive and small device.
Further, although it takes more time to print as compared with the case where four recording heads are used, ink bleeding is less likely to occur and high image quality can be expected.

However, even if a recording head constructed as shown in FIG. 1 so that the nozzle groups for the respective colors do not overlap with each other, ink bleeding between the respective colors cannot be completely prevented. Further, in color printers, color copying machines, and the like, as in the case of the conventional black-and-white only device, it is natural that a high quality black image is required. Therefore, in order to meet this demand, it has been attempted to make the ejection amount of black ink larger than the ejection amount of color ink. However, in this case, there has been a problem that ink bleeding becomes remarkable at the boundary between the black image and the color image, and the printing quality becomes extremely poor.

It is an object of the present invention to provide an ink jet recording method capable of obtaining a high quality image with reduced ink bleeding at the boundary between a black image and a color image.

[0009]

In view of the above, the present invention has a plurality of colors of m ejecting portions for ejecting black ink and n (n <m) ejecting portions for ejecting color ink. Along with, in an inkjet recording method for relatively scanning a recording head configured to not eject the black and color ink ejecting portions of each color in the scanning direction to obtain a multicolor image,
When a black image to be printed with black ink and a color image to be printed with color ink are adjacent to each other, the black ink is ejected so that the scanning for forming the black image and the scanning for forming the color image are not continuous. It is characterized in that a predetermined discharge part is used from the discharge part group.

The color inks are yellow, magenta and cyan.

Further, the number m of ejected portions of the ejection portion group for ejecting black ink and the number n of ejected portions of the ejection portion group for ejecting color ink satisfy m ≧ 2n.

[0012]

EXAMPLES The present invention will be described in detail below with reference to examples.

(Embodiment 1) FIG. 1 schematically shows a recording head used in the ink jet recording method of the present invention. 1 is a recording head, 10 is a nozzle (ejection part), 10
a is a nozzle for ejecting yellow ink, 10b
Is a nozzle for ejecting magenta ink, 10c is a nozzle for ejecting cyan ink, and 10d is a nozzle for ejecting black ink. The nozzle groups of the respective colors are configured so as not to overlap in the scanning direction, and spaces 10e, 10 are provided between the nozzle groups of the respective colors.
f and 10g are provided. The nozzle group 10a, the nozzle group 10b, and the nozzle group 10c each have 24 nozzles, and the nozzle group 10d has 48 nozzles, 3 nozzles per inch.
They are arranged at a density of 60 (360 dpi). In addition, the discharge amount of the nozzle 10d is about 80 ng,
The discharge amounts of a, 10b, and 10c are about 40 ng.

A printing method for printing various images with the recording head shown in FIG. 1 will be described below.

FIG. 2 illustrates a case where only a black image is printed by using the black ink ejection nozzle group 10d. All 48 nozzles of the nozzle group 10d are used, and when the scanning of the recording head is completed, 48 nozzles are used. The next line is printed by feeding the recording paper by the minute. This method is especially suitable for FIG.
Even if the image on one page is only black as shown in (a), or if there is a mixture of black and color images on one page as shown in FIG. 8 (b), the recording paper is fed. This is effective for printing the black image portion (the area a and the area c in FIG. 8B) when the black image and the color image are separated in the direction, and has an advantage that the recording speed is high. When this type of recording head is used, the feeding pitch of the recording paper in the portion where the color image exists (area b in FIG. 8B) is basically 24 nozzles.

FIG. 3 shows a nozzle 10 for ejecting color ink.
This shows a case where a color image is printed using a, 10b, 10c, and the black ink ejection nozzle 10d, and 24 nozzles are used for each color ((5) in the same figure). In the figure, as a nozzle for ejecting black ink, a nozzle closer to the cyan ink ejecting nozzle 10c is used. In the figure, Y represents printing with yellow ink, M represents printing with magenta ink, C represents printing with cyan ink, and B represents printing with black ink.

A process for forming a color image will be described with reference to FIGS. FIG. 3A shows that the recording head 1 is scanned at the illustrated position, and at that time, the upper half 24 nozzles of the black character "B" are printed. Then, the recording paper is fed by 24 nozzles, and
From the state of (b), the remaining lower half of the black character "B" and the upper 24 nozzles of the cyan character "C" are printed. Further, the recording paper is fed by 24 nozzles to print the lower half 24 nozzles of the cyan character "C" as shown in FIG.
The upper half 24 nozzles of the magenta character "M" are printed. The above operation is performed as shown in FIGS. 3D and 3E, and the four-color printing is completed.

By the way, in the image shown in FIG. 3, since the images of the respective colors are not adjacent to each other, the print quality is not particularly deteriorated due to the color bleeding. However, in the case of the image shown in FIG. 4, since the black character “B” exists in each of the yellow, magenta, and cyan backgrounds, color bleeding easily occurs at the boundary between black and color. In particular, it is preferable to design the discharge amount of black ink per dot to be larger than that of color ink from the viewpoint of print quality of a black image. Therefore, the blurring of the boundary between the black image and the color image is particularly preferable. Likely to happen.

Therefore, in the recording method according to the first embodiment of the present invention, using the recording head shown in FIG. 1 to obtain an image in which a black image and a color image are adjacent to each other as shown in FIG. As described with reference to FIGS. 4A to 4F, the number of nozzles used when printing a black image is 24 nozzles in the lower half.

First, as shown in FIG. 4A, a portion corresponding to the upper half of the black character "B" is printed by using the lower half nozzle of the black ink ejection nozzle 10d. Next, after feeding the recording paper for 24 nozzles, the black ink ejection nozzle 1
Using the lower half of 0d, the remaining lower half of the black character "B" is printed (FIG. 7B). Further, after feeding the recording paper, the upper half of the background portion is printed by the cyan ink ejecting nozzle 10c ((c) in the figure). After the recording paper is fed, the lower half of the cyan background portion is printed by the nozzle 10c, and the upper half of the magenta background portion is printed by the nozzle 10d (FIG. 9 (d)). The same operation is repeated until printing is completed as shown in FIG. 4 (f).

Here, the image of FIG. 3 (f) is shown in FIG.
Comparing the process of printing in the procedure of (e) with the process of printing the image of FIG. 4 (g) in the procedure of FIGS. 4 (a) to 4 (f), a color image corresponding to 48 nozzles in the paper feeding direction is obtained. In the latter case, the number of scans of the recording head for obtaining the value is one. That is, in the latter method, the nozzles used for black ink ejection are the lower half, and the cyan ink ejection nozzle 10 is used.
Since c is separated by 1 scan, that is, 24 nozzles, the number of scans is increased by 1. Therefore, in the latter method, even if the black image and the color image are adjacent to each other, the time from the printing of the black image to the printing of the color image is longer than that in the former method, so that the bleeding of the adjacent portion is unlikely to occur. .

As described above, by using the recording method of this embodiment, even if the black image and the color image are adjacent to each other, the nozzles for printing the black image can be appropriately set so that the black image and the color image can be printed. Since the printing timing can be delayed as compared with the normal printing, a high-quality color image without bleeding between colors can be obtained.

Further, the number of reciprocating scans of the recording head increases only once when printing one page of recording paper.
It has almost no effect on the actual recording time.

In the embodiment described above, FIG.
Image was printed with an ink ejection frequency of 6 kHz and a time from the start of scanning of the recording head to the start of the next scan of about 1 second, a high-quality image with no bleeding at the boundary between the black image and the color image was obtained. I was able to get it.

(Embodiment 2) As in Embodiment 1, the recording head shown in FIG. 5 includes a yellow ink ejection nozzle 10a, a magenta ink ejection nozzle 10b, a cyan ink ejection nozzle 10c, and a black ink ejection nozzle 10d. The black ink ejection nozzles are 64 nozzles, and the other color ink ejection nozzles are 24 nozzles. Spaces 10e and 10f for eight nozzles are provided between the yellow ink ejecting nozzle 10a and the magenta ink ejecting nozzle 10b and between the magenta ink ejecting nozzle 10 and the cyan ink ejecting nozzle 10c.
However, a space 10g for 16 nozzles is provided between the cyan ink ejection nozzle 10c and the black ink ejection nozzle 10d.
Is provided. The ejection amount of each nozzle is the same as that in the first embodiment.

Further, since this recording head is provided with the space, it is easy to form a liquid chamber for supplying ink to each color nozzle, and a temperature detecting sensor for the recording head can be provided in the space. In addition, there is an advantage that the present invention can be easily applied to bring out the effect.

FIG. 6 shows the recording paper feed direction in the case where an image in one page is only black using this recording head, or a black image and a color image are mixed in one page. It shows a recording method when a black image portion is printed when a black image and a color image are separated. That is, a black image is printed using all 64 nozzles, and the feed pitch of the recording paper is also set for 64 nozzles.

Next, the recording method for printing the image shown in FIG. 4 (g) using this recording head will be described with reference to FIGS.
An explanation will be given using (h). As is clear from the figure, when printing a black image, among the nozzles 10d for ejecting black ink, the nozzle at a predetermined position from the top in the figure is used. Specifically, 24 nozzles from the 25th nozzle to the 48th nozzle counted from the top in the figure are used.

First, as shown in FIG. 7A, the upper half of the black character "B" is printed using the 25th to 48th nozzles. Next, feed the recording paper by 24 nozzles,
As shown in FIG. 7B, the lower half of the black character "B" is printed using the same nozzle. At this time, color printing is not performed. Next, after feeding 24 nozzles of the recording paper, a part of the cyan background portion is printed by the cyan ink ejecting nozzle 10c. The following is about printing the background of each color.
Although the process is performed for four nozzles each, the details are omitted because they are the same as in the first embodiment. In this embodiment, the recording head shown in FIG.
A total of 8 scans are required to print the image shown in (g).

As described above, since the 25th to 48th nozzles of the black ink ejection nozzles are used, the color ink which is the closest to the black character immediately after the black character is printed, specifically, Since there is free time for one round trip before cyan ink is printed,
Bleeding does not occur in the adjacent area. When the image of FIG. 4 (g) was printed under the same conditions as in Example 1, the quality was the same as in Example 1.

(Embodiment 3) When the same recording head as in Embodiment 2 is used to print an image in which an adjacent boundary between a black image and a color image is present, the black ink ejection nozzles are numbered from the 41st nozzle to the 64th nozzle. Nozzle of was used. Since the feeding pitch of the recording paper is equivalent to 24 nozzles as in the second embodiment, the earliest color image (cyan) from the black image printing at the adjacent boundary portion is printed.
There is a time lag of two scans before and after printing. Therefore, FIG.
When the same image as (g) was printed, it was possible to obtain a higher-quality image with no bleeding than in Example 2.

FIG. 9 is a perspective view of an ink jet printer equipped with an ink cartridge and a carriage 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 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 fed to the front surface of the paper feed roller 102 for printing. 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 print head 102.

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

The components of the ink used in this example are as follows. (Yellow) C.I. I. Direct Yellow 86 3 parts Diethylene glycol 10 parts Isopropyl alcohol 2 parts Urea 5 parts Acetinol EH (Kawaken Chemical) 1 part Water balance (magenta) C.I. I. Acid Red 289 3 parts Diethylene glycol 10 parts Isopropyl alcohol 2 parts Urea 5 parts Acetinol EH (Kawaken Chemical) 1 part Water balance (cyan) C.I. I. Direct Blue 199 3 parts Diethylene glycol 10 parts Isopropyl alcohol 2 parts Urea 5 parts Acetinol EH (Kawaken Chemical) 1 part Water balance (black) C.I. I. Direct Black 154 3 parts Diethylene glycol 10 parts Isopropyl alcohol 2 parts Urea 5 parts Acetynol EH (Kawaken Chemical) 1 part Water balance

The print head 102 will be described in detail with reference to FIG. 10. Yellow, magenta, cyan, and black ejection port groups are arranged in a straight line on the front surface of the print head 102. Each group has 24 ejection ports for yellow, magenta, and cyan, and 64 ejection ports for black, and has an interval of 8 nozzles between colors and an interval of 16 nozzles between black and colors. In addition, these nozzles have a density of 36 nozzles per inch (360 dpi).
It is located in. Normally, when printing only a black image, all 64 ejection ports in the black ejection port group are used, and when printing a color image including a black image, 24 ejection ports for each color of yellow, magenta, cyan and black are used. To use.

Each of these ejection ports is provided with an ink liquid passage communicating with the ejection port, and a common portion for supplying ink to these liquid passages is provided behind the portion where the ink liquid passage is provided. A liquid chamber is provided. An ink path corresponding to each of the ejection ports is provided with an electrothermal converter that generates thermal energy used for ejecting ink droplets from these ejection ports and an electrode wiring pattern for supplying electric power to the electrothermal converter. ing.
These electrothermal converters and electrode wirings are formed by a film forming technique on a 201 substrate made of silicon or the like. Further, the ejection port, the ink liquid passage, and the common liquid chamber are formed by stacking a partition wall made of a 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.

The silicon substrate and the printed circuit board 202 are the same aluminum plate 203 in parallel with each other, and the protruding pipe 2
Numerals 04 to 207 project from a plastic member 208 called a distributor that spreads 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, one for yellow, one for magenta, one for cyan, and one for black, and each common liquid chamber is connected to a pipe.

About 40 ng from the yellow, magenta, and cyan discharge ports provided in the print head 102.
Ink of about 80 ng is ejected from the ejection port for black.

FIG. 11 is an electrical control block diagram of the color ink jet printer described above.

Reference numeral 301 denotes a system controller for controlling the entire apparatus, which has a storage element (RO) in which a control program including a microprocessor is housed.
M), a memory element (RAM) and the like used when the microprocessor performs processing are arranged. Reference numeral 302 denotes a driver for driving the print head in the main scanning direction, and similarly 303 denotes a driver for moving 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 movement 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.
The data is accumulated until the data is read from the system controller 01. 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 the size of the frame memory.

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 denotes a print control unit for appropriately controlling the print head according to a command from the system controller, and a print control unit 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, which is controlled by a signal from the print controller 310.

(Comparative Example) In Example 2, when the same image as in Example 2 was printed by using the black ink ejection nozzles from the first nozzle to the 24th nozzle, an image having black characters in the cyan background portion In particular, ink bleeding occurred at the boundary between cyan and black.

Therefore, when printing was performed experimentally by gradually increasing the time from the start of scan of the recording head to the start of the next scan from 1 second, the printing time doubled to about 2 seconds and finally Example 2 was obtained. We were able to obtain an equivalent grade.

In each of the above embodiments, the black ink ejection nozzles are set so that the time from the printing of the black image to the printing of the adjacent color image is at least one scan in the printing of the portion where the black image and the color image are adjacent to each other. I was doing, but Figure 3
It may be set when there is no adjacent portion between the black image and the color image as shown in (f).

The present invention brings excellent effects particularly in a recording head and a recording apparatus of a system utilizing heat energy among the ink jet recording methods.

Regarding the typical structure and principle thereof, 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 driving signal corresponding to the recorded information and giving a rapid temperature rise exceeding the nuclear boiling point, heat energy is generated in the electrothermal converter, and the film is heated on the heat-acting surface of the recording head. As a result, bubbles can be formed in the liquid (ink) in a one-to-one correspondence with this drive signal, which is effective. By the growth and contraction of the bubbles, liquid (ink) is ejected through the ejection opening,
Form at least one drop. It is more preferable to make this drive signal into a pulse shape, because the bubble growth and contraction are immediately and appropriately performed, so that the ejection of the liquid (ink) with excellent responsiveness can be achieved. As the pulse-shaped drive signal, U.S. Pat. Nos. 4,463,359 and 4,345 are used.
Those as described in the '262 patent 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, in addition to the combination constitution of the discharge 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. US Pat. No. 4,558,333, US Pat. No. 4,558,333, which discloses a configuration in which a heat acting portion is arranged in a bending region.
A configuration using the specification of No. 459600 is also included in the present invention. In addition, Japanese Laid-Open Patent Publication No. 123670/1984 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. The present invention is also effective as a structure based on Japanese Patent Laid-Open No. 138461/1984, which discloses a structure in which the discharge section is associated with the discharge section.

[0051]

As described above, according to the recording method of the present invention, since bleeding does not occur at the adjacent boundary between the black image and the color image, a high quality recorded image can be obtained. Further, since the bleeding does not occur at the adjacent boundary between the black image and the color image, the ejection amount of the black ink can be made larger than the ejection amount of the color ink, and as a result, the black image has a high density,
High-quality images can be obtained. Moreover, these effects can be achieved with almost no reduction in printing time for one page.

[Brief description of drawings]

FIG. 1 is a diagram illustrating an outline of a recording head used in a first embodiment.

FIG. 2 is a diagram illustrating a process of printing only a black image.

FIG. 3 is a diagram illustrating a process of printing an image in which a black image and a color image are mixed.

FIG. 4 is a diagram illustrating a process of printing an image in which a black image portion and a color image portion have adjacent boundaries.

FIG. 5 is a diagram illustrating an outline of a recording head used in a second embodiment.

FIG. 6 is a diagram illustrating a process of printing only a black image.

FIG. 7 is a diagram illustrating a process of printing the image of FIG. 4 by the method of the second embodiment.

FIG. 8 is a diagram illustrating image types and recording paper feed.

FIG. 9 is a perspective view of an inkjet recording apparatus to which the present invention can be applied.

FIG. 10 is a head mechanism diagram of an inkjet recording apparatus to which the present invention can be applied.

FIG. 11 is a block diagram of an inkjet recording apparatus control circuit to which the present invention can be applied.

[Explanation of symbols]

 1 recording heads 10a, 10b, 10c, 10d nozzle groups for each color

Claims (8)

[Claims] 1. A group of m ejecting portions for ejecting black ink and n (n <m) for ejecting color ink.
A plurality of color discharge units, and a recording head configured to prevent the discharge units of the respective colors for discharging the black and color inks from overlapping each other in the scanning direction. In an inkjet recording method for obtaining a color image, when a black image to be printed with black ink and a color image to be printed with color ink are adjacent to each other, scanning for forming the black image and scanning for forming the color image are performed. An ink jet recording method, characterized in that a predetermined ejection portion is used from the ejection portion group for ejecting the black ink so as not to be continuous. 2. The ink jet recording method according to claim 1, wherein the color inks are yellow, magenta, and cyan. 3. The ink jet recording method according to claim 1, wherein the ejection unit group for ejecting the black ink is arranged at an end of the recording head. 4. The ink jet recording method according to claim 1, wherein a space is provided between the ejection unit groups for the respective colors. 5. The number m of ejection portions of the ejection portion group for ejecting the black ink and the number n of ejection portions of the ejection portion group for ejecting the color ink are m.
The inkjet recording method according to claim 1, wherein ≧ 2n is satisfied. 6. The ink jet recording method according to claim 1, wherein the number 1 of predetermined ejection portions in the ejection portion group for ejecting black ink is 1 ≦ n. 7. The ink jet recording method according to claim 6, wherein the feeding pitch of the recording paper when the black image and the color image are adjacent to each other corresponds to one ejection section. 8. The ink jet recording method according to claim 1, wherein each ink is ejected by thermal energy.