JPH08244254A - Color ink jet recorder - Google Patents

Abstract

PURPOSE: To omit complex color processing and make it possible to reproduce a good image faithfully by use of ink where the first and second colors are blended by providing a recording head which discharges seven colors individually in response to recording signals based on image data. CONSTITUTION: A connector plate 1340 which has connectors arranged outside together with wiring boards 1330 connected electrically with individual recording head units 1200 and are fixed to a frame 1300. On the other hand, although the recording head units 1200 are formed nearly in the same form, of those, since a recording head unit 1200 Bk for Bk ink is connected to a cartridge for the Bk ink of one kind, it has only one ink supply pipe 1210. The remaining recording head units 1200 have two ink supply pipes 1210, respectively. Filters 1211 are provided at the ends of the ink supply pipes 1210.

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 apparatus, and more particularly to a color ink jet recording apparatus having a special color in its image data processing means.

[0002]

2. Description of the Related Art With the widespread use of copying machines, word processors, information processing equipment such as computers, and communication equipment, an ink jet type recording head is used as one of image forming (recording) equipment of these equipment. Those that record digital images are rapidly spreading. Furthermore, with the higher image quality and colorization of the information equipment and communication equipment,
There is an increasing demand for higher image quality and color in recording devices as well. In such a color inkjet recording apparatus, in order to improve the recording speed, a recording head in which a plurality of recording elements are arranged (hereinafter referred to as a multi-head)
In general, a plurality of ink ejection ports and liquid paths arranged in high density is used, and the multi heads for cyan, magenta, yellow, and black are further provided for colorization.

FIG. 12 shows an outline of the structure of a color ink jet recording apparatus according to a conventionally known shade recording method. In this figure, a carriage 700 ejects eight ink tanks 701 each containing four shades of black, cyan, magenta, and yellow and two inks of four shades. Eight multi-heads 702 are mounted for this purpose. FIG. 13 shows the state of each ink ejection port array arranged on the ejection port surface 702A of these multi-heads 702 as seen from the z direction in FIG. 12, and in FIG.
Is an ink ejection port array arranged on the ejection port surface 702A. In this figure, eight ink ejection port arrays are arranged in parallel along the Y axis, but for example, these ink ejection port arrays have some inclination with respect to the Y axis direction on the XY plane of the drawing. May be. In this case, while the head 702 scans in the x direction, recording is performed while shifting the timing in each ink ejection port array 801. Figure 1 again
Returning to 2, the sheet feeding roller 703 and the auxiliary roller 704 rotate in the direction of the arrow in the drawing while holding the recording material (hereinafter referred to as a recording sheet) 705 between the rollers 703 and 704. The sheet 705 is fed in the y direction. Further, reference numerals 706 and 707 denote feed rollers, which feed the recording sheet 705,
Like 3 and 704, it functions to hold the recording sheet 705 at the recording position. On the other hand, the carriage 700 stands by at the home position position h shown by the broken line in the drawing when recording is not performed or when a recovery operation or the like is performed on the multi-head 702.

In the ink jet recording apparatus having such a structure, when a recording start command is received before the recording is started, the carriage 700 at the home position h moves along the carriage guide shaft 708 in the x direction and the movement thereof. At a predetermined timing based on the read signal from the linear encoder 709, four rows of dark and light inks are selectively ejected from the row 801 of ink ejection openings of the multi-head 702 in accordance with the recording signal, and the recording sheet 705 is formed. Only the width D is recorded on the top. The recording sheet 7 is formed by this recording scan.
05, dark and light black ink (K _k , K _u ), cyan ink (C _k , C _u ), magenta ink (M _k , M).
_u ) and yellow ink (Y _k , Y _u ) are deposited in this order to form dots. Thus, the recording sheet 705
When the data recording is completed up to near the edge of the carriage, the carriage 7
00 returns to the original home position h, and the recording in the x direction is repeated again. Since the sheet feeding rollers 703 and 704 feed the sheet in the y direction by the width D shown in FIG. 13 from the end of the first recording to the start of the recording of the second line. In this manner, the recording of the recording width D of the multi-head 702 and the sheet feeding are alternately performed every scanning of the carriage 700, and the data recording on one sheet surface is completed.

FIG. 14 shows an example of an image signal processing circuit in the above-mentioned ink jet recording apparatus. Yellow (Y),
Original image density signals Y _{1 of} magenta (M) and cyan (C),
After M ₁ and C ₁ are color-corrected by the masking circuit 40, the output signals Y ₂ , M ₂ and C ₂ are further processed by the undercolor removal (UCR) / black generation circuit 41. It is converted into new image density signals Y ₃₆ , M ₃₆ , C ₃₆ , and K ₃₆ of yellow, magenta, cyan, and black. Then, the gamma correction circuit 42 performs gamma correction using the gamma correction table based on the characteristic curve shown in FIG.
The image density signals Y ₃₇ , M ₃₇ , C ₃₇ , K ₃₇ are separated into Y _k38 , Y _u38 , ... K _k38 , K _u38 by the density distribution circuit 43, and then sent to the binarization circuit 44, where Image signals Y _k39 , Y _u39 , ... K _k39 , K _{u39 which} are respectively binarized and transferred to the eight multi-heads 702 are generated.

Recently, in order to perform device-independent color output, various methods such as mapping processing have been adopted as color processing methods other than masking processing.

[0007]

However, in the color ink jet recording apparatus such as the above-mentioned conventional example, it takes too much time for the color processing, so that the red (R), green (G), When seven colors of blue (B), cyan (C), magenta (M), yellow (Y), and black (B _K ) are mainly used, high speed output is performed without performing color processing. Therefore, the secondary colors of red, green, and blue have been generated by a one-to-one color mixture of magenta and yellow, yellow and cyan, and cyan and magenta, respectively. Therefore, when the secondary color is generated by mixing the primary colors in a one-to-one manner as described above, the color tones of these R, G, and B secondary colors are required. The adjustment must be performed by adjusting the primary colors of M and Y. For example, adjustment of the color tone of blue can be realized by adjusting cyan and magenta, but other adjustments using cyan or magenta are also possible. It has been difficult to make adjustments using the primary colors, such as adverse effects on the generation of secondary colors of green and red.

Further, in the color ink jet recording apparatus, since liquid ink is ejected and landed and fixed on the recording sheet, color mixture due to bleeding occurs at the boundary between different color inks on the recording sheet. In addition, such a color mixture at the boundary between different colors is more likely to occur as the ink ejection amount increases, so that the color mixing becomes severe at the boundary between the different colors of the secondary colors, and it is difficult to obtain a good image. there were.

An object of the present invention is to solve the above-mentioned conventional problems, and by using seven color inks including a primary color and a secondary color, complicated color processing is omitted and a good image is obtained. Another object of the present invention is to provide a color inkjet recording device that can faithfully reproduce the above.

[0010]

In order to achieve such an object, a color ink jet recording apparatus according to the present invention comprises:
It is characterized by comprising a recording head for individually ejecting inks of seven colors of cyan, magenta, yellow, black, red, green and blue according to a recording signal based on image data.

[0011]

According to the color ink jet recording apparatus of the present invention, recording inks of four colors of cyan, magenta, yellow and black as well as three colors of red, blue and green are used. By ejecting from each recording head, the ink itself can be adjusted without complicated color processing, and the seven colors of RGBCMYB _K , which are important as a color printer, can be faithfully realized.

Further, since the R, G, B secondary colors are recorded by using the R, G, B inks respectively, the ink ejection amount is reduced, and bleeding occurs at the boundary of different colors, which is a particular problem in the secondary colors. Can be suppressed.

Furthermore, the color reproduction range can be widened by using red, blue and green inks having high saturation.

[0014]

Embodiments of the present invention will be described in detail and specifically below with reference to the drawings.

(First Embodiment) First, the mechanical structure of a color ink jet recording apparatus according to the present invention will be described with reference to FIGS. In FIG. 1, 1100
As a general rule, each of them is a cartridge type ink tank that can separately store two types of ink, as described later,
Reference numeral 1200 is a recording head unit that is held by the frame 1300 and is capable of ejecting ink of two different colors in principle. Here, the above-mentioned four ink tanks 1
As shown in FIG. 2, 100 is mounted on a carriage 700 in a state of being connected to a corresponding recording head unit 1200 via a frame 1300, and individual recording is performed while the carriage 700 is moving along a carriage guide shaft 708. Ink of different colors is selectively ejected from the ink ejection ports of the head unit 1200, and the recording sheet 7
Recording is done on 05.

FIG. 3 shows an assembled state of the recording head unit 1200 which is positioned and fixed to the frame 1300.
Here, 1310 is a plurality of ink supply pipe holding holes 1320.
A frame cover 1330, a wiring board 1330 electrically connected to each recording head unit 1200, a wiring board 1330 and a connector (not shown) disposed outside, and attached to a frame 1300. It is a fixed connector plate. On the other hand, the recording head unit 120
0 is formed in almost the same form, but among them, the recording head unit 1200B _K for B _K ink is one type of B _K.
Since it is connected to an ink cartridge (not shown), only one ink supply pipe 1210 is provided, and each of the other recording head units 1200 has two ink supply pipes 1210.
10 are provided. 1211 is an ink supply pipe 121
It is a filter provided at the end of 0.

As shown in this figure, each of the plurality of recording head units 1200 is positioned and supported within the frame 1300 so as to improve the accuracy of the mutual landing positions. The unit 1200 includes a support 1220 and a heater board 1.
230, a wiring board 1240, a grooved top plate 1250, a pressing spring 1260, an ink supply member 1270 for supplying ink to the recording head portion, and the like. Furthermore, FIG.
Further, FIG. 5 is an exploded view of a portion particularly related to the ink ejection function in such a recording head unit 1200. That is, as shown in FIG. 4, the heater board 1230 and the wiring board 1240 on which the wirings connected to the respective signal lines on the heater board 1230 are formed are fixed to the support 1220 with an adhesive or the like, and the heater board A grooved top plate member 1250 having an ink ejection port surface forming plate (orifice plate) 1251 on 1230 is fixed by a pressing spring 1260. Note that reference numerals 1261 and 1262 are locking claws and rear legs that are provided on the presser spring 1260 for attachment to the support 1220. Then, the ink supply member 1270 is further attached to the support 1220.
1221 is a hole related to the engagement, and is fixed by heat fusion after the engagement.

FIG. 5 shows the grooved top plate 1250 in an upside-down form. The grooved top plate 1250 according to this embodiment has common liquid chambers 1252 and 1253 which are isolated from each other. Reference numerals 1252 and 1253 denote ink supply tubes 1210 and 121 of the ink supply member 1270 shown in FIG. 4, respectively.
Ink of different colors is supplied from 0. Further, in FIG. 5, 1254 and 1255 are common liquid chambers 1252 and 125.
A liquid passage communicating with No. 3 and reference numerals 1256 and 1257 are ink supply ports for supplying different color inks to the common liquid chambers 1252 and 1253, respectively. The orifice plate 1251 has the above-mentioned liquid paths 1254, 12
An ink ejection port (not shown) corresponding to 55 is provided. The outer peripheral portion of the grooved top plate 1250 and the surroundings of the common liquid chambers 1252 and 1253 are liquid-tightly sealed by a sealant.

The basic recording operation of the color ink jet recording apparatus having the above-mentioned structure is the same as that of the recording apparatus shown in FIG. 12, but according to this example, R, G and B are used. , C, M, Y, and B _K inks are ejected at predetermined timings respectively, and a high-quality color image can be recorded by a secondary color with a high saturation while reducing the ink ejection amount. .

However, for black B _K , R, G,
Since it has twice as many ink ejection openings as B, C, M, Y ink ejection openings, if B _K is printed at one time to fill the width of the ejection opening array, it will be printed twice for each pixel. Each time, that is, twice as much ink is ejected. Therefore, by setting the pixels to be recorded at one time to be thinned and recorded, ink is ejected and recorded once for each pixel.

FIG. 6 shows a configuration example of the image signal processing circuit in the above-mentioned ink jet recording apparatus. First, the original image luminance signals R, G, B of the secondary colors red, green, blue are converted into cyan, magenta, yellow density signals C, M, Y by a luminance density signal conversion circuit (not shown), and then the lower color The removal (UCR) / black generation circuit 11 further adds C ′,
The signals are converted into M ', Y', and B _K 'signals. And C ',
The secondary color signal generation circuit 12 further generates C ″, M ″, Y ″ and further R ″, G ″, B ″ signals from the M ′ and Y ′ signals, and the gamma correction circuit 13 as a color processing circuit. Is converted into C ₁ , M ₁ , Y ₁ , B _{K 1} , R ₁ , G ₁ , and B ₁ signals, and then binarized by a binarization circuit 14 to obtain each of the seven color inks. _{C 2, M 2, Y 2} , B K2, R 2, G as a binary signal to the recording head unit but supplied
₂ and B ₂ are respectively sent to form an image.

First, FIG. 7 shows the above-described undercolor removal (UCR).
An example of a signal conversion process by the black generation circuit 11 is shown as a model diagram. The portion shown by hatching in (A) of FIG Min (C, M, Y) to generate a signal value B _K 'of B _K expressed in black as shown in the right, C, M, for Y is The value obtained by subtracting Min (C, M, Y) from each signal value is shown in FIG.
(B), new signal values C ', M', and Y'are generated. Here, Min (C, M, Y) represents the minimum value of CMY signal values.

Next, the processing steps in this case performed by the secondary color signal generation circuit 12 of FIG. 8 will be shown as a model diagram. Here, signals of R, G, B are generated by using the signals of C ', M', Y'converted by the undercolor removal (UCR) / black generation circuit 11, and in this example, (A) is used. As shown, since the Y signal value is 0 as a result of the conversion by the undercolor removal (UCR) / black generation circuit 11, the Min (C) represented by the lattice part, which is the minimum value of the C and M signal values. , M) is the signal value of B expressed in black, and the signal values of C and M in this case are Min (C,
It is generated as a signal value obtained by subtracting the value of M).

In the examples shown as models in FIGS. 7 and 8, the density signals C, M, and Y of the secondary color luminance conversion for one pixel have the signal values as shown in FIG. As for the example of the process of generating the signal value of blue B in the case of having it, the signal values of red R and green G can be similarly generated by the combination of different values of the above signal values C, M and Y. .

Therefore, the signals Y ₂ , M ₂ , C ₂ , B _K2 , R relating to the ink ejection of the seven colors thus obtained are obtained.
_{Based on 2} , G ₂ , and B ₂ , ink is ejected from the corresponding recording head unit in such a manner that 7 colors of ink are combined for each pixel, and recording is performed, so that black, red, green, blue of business graphics, etc. are recorded. It is possible to faithfully represent the seven colors required by the user with respect to those using the seven colors of yellow, yellow, magenta, and cyan as seeds.
In addition, since RGB, which is a secondary color, is not generated by mixing with a primary color for an image that mainly uses 7 colors, the amount of ink ejected per unit area is reduced, and color mixture at different color boundaries occurs. It becomes possible to prevent it. Furthermore, even when a full-color image is recorded, the number of colors that can be represented by each pixel is increased, so that more colors can be represented.

(Second Embodiment) R in the first embodiment,
The input image data of G and B are subjected to various processings to be generated as data for each color of RGBCMYB _K , and then binarization processing is applied to each signal to a recording head that ejects ink. A color image was formed by being supplied as binary data.

However, in order to perform such a process, the number of processes is much larger than that of the conventional process, and it takes time for the process. Therefore, in this embodiment, as shown in FIG. 9, the binarization circuit 14 binarizes the four colors of C, M, Y, and B _K as in the prior art, and then the secondary color signal generation circuit 15 Then, only for a pixel in which any two colors of C, M, and Y overlap, R ₂ , G ₂ ,
The pixel is recorded by substituting B ₂ .

That is, C, M, Y, B _K
Output data C ₂ ′, M ₂ ′, Y ₂ ′ for 7 colors of C, M, Y, _BK , R, G, B from binary data C ₂ , M ₂ , Y ₂ , _{BK 2} for 4 colors of , B _K2 ′, R ₂ , G ₂ , B ₂ are generated.

[0029]

## EQU1 ## R = M and YG = Y and CB = C and MC = C xor (G or B) M = M xor (B or R) Y = Y xor (R or G) where and Represents a logical product, or represents a logical sum, and xor represents an exclusive logical sum.

By performing such data processing in the secondary color signal generating circuit 15, B is recorded on the pixels on the recording sheet where C and M overlap, and similarly, M and Y are R and Y. C and G will be recorded respectively.
In FIGS. 10 and 11, cyan is 50% and yellow is 25.
The recording state on the recording sheet when the recording signal of% is binarized by the Bayer type dither matrix is shown. Normally, cyan recording dots 20C and yellow recording dots 2 arranged as shown in FIGS. 10A and 10B.
An image is formed by overlapping and recording 0Y as shown in (C). However, cyan recording dot 20C
An image can be formed only with the green recording dots 20G.

According to the second embodiment, the secondary colors R,
Up to 200 for G and B per unit area
It was necessary to drive in 100% of the ink, whereas 100%
Since the R, G, and B colors can be selected independently of the C, M, and Y inks, the output image does not become dark and a good image with high gradation is obtained. be able to.

Further, the R, G, B binary signals are converted into R, G, B
Since it can be generated by a simple logical expression from the binary signals of C, M, and Y instead of being generated after binarizing from the multi-valued signal of It is possible to obtain a good image that does not change and has no blurring in the boundary between the primary color and the secondary color.

In the embodiment described above, B _K
Other than the above, a removable cartridge-type ink tank that contains ink of two different colors and a frame frame holds B _K
Other than the above, an example of application to a serial type color ink jet recording apparatus in which two types of recording head units capable of individually ejecting ink and a type of recording head unit are integrally mounted on a carriage and recording is performed during scanning of the carriage will be described. I've been
However, the application of the present invention is not limited to the case where the cartridge type ink tank and the plurality of recording head units held by the frame are integrally mounted on the carriage, and each recording head has an ink tank for each color. The present invention can be widely applied to a serial type color ink jet recording apparatus in which the color ink tanks are not mounted on the carriage but fixed to the recording apparatus side.

Further, not only the serial type but also a full line type multi type recording head arranged in parallel is provided for each color, and different inks are selectively ejected at a predetermined timing according to the feeding of the recording material. It goes without saying that the present invention can be applied to a color ink jet recording apparatus and a printer of a type that performs recording by using a printer, and further to an apparatus having the function of such a printer, for example, a textile printer.

Further, regarding the structure of the recording head itself, in addition to the arrangement of the liquid passage and the ink ejection port as described with reference to FIGS. 4 and 5, ink is ejected at a predetermined timing, and the ink is ejected. The present invention can be widely applied to a form in which recording is performed by dots, for example, by driving a piezoelectric element.

[0036]

As described above, according to the color ink jet recording apparatus of the present invention, cyan, magenta,
Since a recording head for individually ejecting inks of seven colors of yellow, black, red, green and blue is provided according to a recording signal based on image data, C, M, Y,
A good image can be obtained by eliminating the bleeding at the boundary between the primary color and the secondary color, which tends to occur when the four color inks B _K are used.

In a business graphic or the like, it is possible to generate each color independently for a user who forms a color image mainly using seven colors of C, M, Y, B _K , R, G and B. Therefore, 7 colors can be recorded as required without performing complicated processing such as color processing.

[Brief description of drawings]

FIG. 1 is a perspective view showing the outline of the configuration of a color inkjet recording apparatus according to the present invention.

FIG. 2 is a perspective view showing an assembled state of a color inkjet cartridge and a recording head unit according to the present invention.

FIG. 3 is a perspective view showing the recording head unit of FIG. 2 in an exploded manner.

FIG. 4 is an exploded perspective view of a single recording head unit.

FIG. 5 is a perspective view showing the grooved top plate of the recording head unit according to the present invention as viewed from the heater board side.

FIG. 6 is a block diagram showing the process of image signal processing according to the first embodiment of the present invention together with the circuit configuration thereof.

FIG. 7 is an explanatory diagram showing an example of signal conversion in the UCR / black generation circuit according to the first embodiment of the present invention in the processes of (A) and (B).

FIG. 8 is an explanatory diagram showing an example of signal conversion in the secondary color signal generation circuit according to the first embodiment of the present invention in the process of (A) and (B).

FIG. 9 is a block diagram showing an image signal processing process according to the second embodiment of the present invention together with its circuit configuration.

FIG. 10: Cyan 50%, Yellow 25% by the conventional method
It is a figure which shows the process at the time of recording by (A), (B), (C).

FIG. 11: Cyan 50%, Yellow 25% in the second embodiment
It is explanatory drawing which shows the process at the time of recording by (A), (B), (C).

FIG. 12 is a perspective view showing an outline of the configuration of a conventional example of a color inkjet recording apparatus.

FIG. 13 is an explanatory diagram showing, as an example, an arrangement state of ink ejection ports of a conventional example.

FIG. 14 is a block diagram showing a process of image signal processing according to a conventional example together with its circuit configuration.

FIG. 15 is a characteristic curve diagram showing an example of a γ value correction curve for converting an input density signal into an output density signal.

[Explanation of symbols]

11 UCR / black generation circuit 12, 15 secondary color signal generation circuit 13 γ correction circuit 14 binarization circuit 20C, 20Y, 20CY, 20G ink (recording) dots 700 carriage 705 recording material (recording sheet) 1100 ink tank ( Cartridge type) 1200,1200B _K Recording head unit 1230 Heater board 1250 Groove top plate (member) 1252, 1253 Common liquid chamber 1254, 1255 Liquid path 1300 Frame frame

Front page continuation (72) Inventor Kiichiro Takahashi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (5)

[Claims] 1. A color ink jet recording comprising a recording head for individually ejecting inks of seven colors of cyan, magenta, yellow, black, red, green and blue according to a recording signal based on image data. apparatus. 2. A color signal generating means for generating the black, red, green and blue recording signals based on image data relating to the cyan, magenta and yellow densities. Color inkjet recording device. 3. The color ink jet recording apparatus according to claim 1, wherein the recording head individually ejects the inks of the seven colors in accordance with the recording signals generated by the color signal generating means. . 4. The ink of seven colors is contained in four cartridge type ink tanks, and the recording head can individually eject the ink supplied from the ink tanks. 5. The color inkjet recording device according to any one of 1. 5. The serial head according to claim 1, wherein the recording head is mounted on a carriage, and the recording is performed by individually ejecting the inks of the seven colors during scanning of the carriage. The color ink jet recording apparatus according to the item.