JPH01272459A - Recording apparatus - Google Patents

Abstract

PURPOSE:To obtain an output image sufficiently having color reproducibility, by outputting image data of cyan (C), magenta (M), yellow (Y), black (Bk) and white (W) from inputted image data and emitting the inks having the colors corresponding to the outputted image data of the respective colors to a recording medium to perform recording. CONSTITUTION:The image data of R(red), G(green) and B(blue) from an image data input means 20 are converted to the image data of C, M and Y by a complementary color converting part 31 to be outputted to a gradation correction part 32 and gradation is corrected so that the values of the image data at every colors and the density of a manuscript become linear relation. The image data are converted to image data of C, M, Y and Bk by a black processing part 33 and converted to image data of C, M, Y, Bk and W by a color correction part 34. A dot pattern generator 22 applies A/D conversion to the image data corrected in gradation by a gradation correction part 35 to store the converted data in a printer memory 23. A printing head is driven according to each corresponding drive signal to emit inks C, M, Y, Bk, W. As a result, the color reproducibility of an output image can be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a recording apparatus that outputs a full-color image using, for example, an inkjet recording method.

(Prior Art) In recent years, with the rapid trend toward color display devices, various inkjet color printers have been developed.

In inkjet color printers that have been developed to date, full-color images are obtained by mixing three or four color inks on recording paper.

−The image data processing process applied to boat fishing is
R (red), G (green), and B (blue) image data from an image data input means such as a color scanner or color TV camera are converted into cyan (C), magenta (M), and yellow (Y) by a complementary color conversion unit. The C, M, and Y image data are converted into CSM, Y image data, and the C, M, and Y image data are tone-corrected in a tone correction section so that the image data values for each color have a linear relationship with the original density. From each image data of
Extract the image data of k), and convert the image data of Bk to C,
Subtraction from each image data of MSY (black processing is performed in the black processing section, then color correction of the image data of C5M5Y is performed to correct the turbidity due to unnecessary absorption of ink, and finally the value of each image data and the output image The gradation correction unit performs gradation correction so that the density has a linear relationship.

This tone-corrected image data is sent to a dot pattern generator. As a result, the dot pattern generator A/D converts the image data, determines (binarizes) printing dots in a 2 x 2 (n x n) matrix according to this digital value, and then converts the image data into 1,
Stored in printer memory. This stored dot image is sent from the printer memory to the head driver, so that a full-color output image can be obtained on the recording paper.

The black processing section is created by mixing C, M, and Y inks.
In order to improve the problem that it is difficult to express black Bk and the amount of ink is large, which causes bleeding, dripping, etc., black Bk image data is extracted from each of the above CSM and Y image data. It is designed to be extracted.

However, as mentioned above, such inkjet color printers print C, M, and Y.

Since a full-color output image is obtained by mixing each Bk image data, the hue can be changed to some extent, but it is not possible to correct the decrease in brightness due to color mixing of inks, and the brightness and saturation cannot be corrected. was steadily decreasing compared to the primary colors.

Therefore, it is not possible to correct the decrease in brightness due to color mixing of inks, and it is not possible to express bright or pale colors by changing the brightness, and it is difficult to obtain an output image with sufficient color reproducibility. had not been reached.

(Problems to be Solved by the Invention) This invention eliminates the drawback that it is not possible to obtain an output image with sufficient color reproducibility, and the present invention aims to eliminate the drawback that it is not possible to obtain an output image with sufficient color reproducibility. The purpose is to provide equipment.

[Structure of the Invention] (Means for Solving the Problems) The recording device of the present invention includes an image data input means for inputting image data, and cyan, magenta, yellow, black, and It is comprised of an image data processing means for outputting white image data, and a recording means for ejecting ink of a corresponding color onto a recording medium in accordance with the image data of each color from the image data processing means.

(Operation) This invention outputs cyan, magenta, yellow, black, and white image data from input RSG and B image data, and inks of corresponding colors according to the outputted image data of each color. The recording is performed by ejecting the liquid onto the recording medium.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 2 shows the configuration of the main parts of the recording apparatus. That is, the recording paper (recording medium) 1 is supplied from a roll paper 2, guided by a guide roller 4.5, and transported in the Y direction while being held between a pair of transport rollers 6.7. The conveyance rollers 6.7 are rotated by the conveyance motor 3.

On the other hand, print heads 8C, 8M, 8Y, and 88k.

8W is mounted on the carriage 9. This carriage 9 is movably mounted on a guide shaft 12.13 and has a belt 11 driven by a movement motor 10.
As a result, the recording paper 1 is reciprocated in the X direction (direction perpendicular to the transport direction Y of the recording paper 1).

In addition, the above print heads 8C, 8M, and 8Y.

Flexible cable 14 for 88 and 8W, respectively.
14W is connected to C, 14M, 14Y, and 148, and further the print head 8C.

8M, 8Y, 88, and 8W are each tube 15C
, 15M, 15Y, 158, and ink tanks 16C, 16M, 16Y via 15W.

168 is coupled with 16W.

The above ink tanks 16C, 16M, and 16Y.

Cyan (C), magenta (M), yellow (Y), black (Bk), and white (W) inks are stored in tubes 168 and 16W, respectively, and tubes 15C, 15M, and 15Y, respectively.

158, print heads 8C and 8M pass through 15W.

It is designed to be supplied to 8Y, 88, and 8W.

The above-mentioned ink mainly consists of a colorant and a solvent, and for boat fishing, a water-soluble dye is used as the colorant, and water, diethylene glycol, etc. are used as the solvent, such as cyan (C).
Ink dyes include acid blue 9 and magenta (M
) Ink dyes include acid red 87 and yellow (
Y) Fluorescent whitening dyes such as Acid Yellow 23 are used as the dye for the ink, Direct Black 19 is used as the dye for the black (Bk) ink, and Fluorescent Brightening Agent 90 is used as the dye for the white (W) ink. It is now possible to

Therefore, during the recording operation, the head driver 24 (described later)
The drive signals from each flexible cable 14C
, 14M, 14Y, 148k.

Print heads 8C, 8M, 8Y via 14W.

88k, 8W is supplied. As a result, the print head 8
C, 8M, 8Y, 88, and 8W move in the X direction together with the carriage 9 and print cyan (C), magenta (M), yellow (Y), and black (Bk) according to the supplied recording signal. , white (W) ink is ejected to perform color recording on the recording paper 1.

FIG. 1 shows the main parts of the electric circuit.

That is, the image data input section (image data manual means) 2
0 is composed of a color scanner, a color TV camera, etc., and outputs image data of R (red), G (green), and B (blue).

The R and GSB image data from the image data input section 20 are supplied to an image data processing section 21.

This image data processing section 21 is connected to the image data input section 20.
R, G, B image data from C, M.

The image data is converted into Y, Bk5W image data and output.

That is, as shown in FIG.
A complementary color conversion unit 31 converts image data into cyan (C), magenta (M), and yellow (Y) image data, and the value of image data for each color from this complementary color conversion unit 31 and document density have a linear relationship. A gradation correction unit 32 corrects the gradation of each image data of CSM and Y so that the image data of C, M, and Y from this gradation correction unit 32 as shown in FIG. 5(a). Extract black (Bk) image data from
The black processing unit 33 performs black processing to subtract the Bk image data from the C and MSY image data to convert it into CSM, Y, and Bk image data as shown in FIG. Color correction is performed on each of the C, M, and YSBk image data from the black processing section 33 to correct turbidity due to unnecessary absorption of ink and decrease in brightness due to color mixing of ink. Na, CSM, YSBk.

The color correction section 34 converts into each image data of W, and gradation correction is performed so that the values of each image data of C, M, YSBk, and W from this color correction section 34 have a linear relationship with the output image density. It is composed of a gradation correction section 35 that performs the correction.

The complementary color conversion unit 31 includes a logarithmic amplifier 31 a that converts the supplied RSGSB image data into cyan (C), magenta (M), and yellow (Y) image data, respectively.
This is a well-known structure consisting of s 31 b s 31 c.

The gradation correction unit 32 is a well-known unit that includes operational amplifiers 32 a s 32 b s 32 c that correct the gradation of the supplied C, M, and Y image data. .

The black processing unit 33 improves the problem that it is difficult to express black Bk due to color mixing of C, M, and Y inks, and that the amount of ink increases, which causes bleeding, dripping, etc. In order to do this, the black Bk image data is extracted from each of the C, M, and Y image data, and the minimum value of the supplied C5M5Y image data, or the minimum value that discriminates the Bk image data. Discrimination circuit 33a
1. A subtracter 3 that subtracts the supplied C, M, and Y image data by the minimum value from the minimum value discrimination circuit 33a.
This is a well-known structure composed of 3b, 33c, and 33d.

The gradation correction unit 35 is an operational amplifier 35as 35bs 35 that corrects the gradation of the C5M5Y%Bk and W image data supplied from the color correction unit 34, respectively.
c, 35ds 35e.

The output of the image data processing section 21, that is, the image data whose tone has been corrected by the tone correction section 35, is sent to the dot pattern generator 22.

As a result, the dot pattern generator 22 A/D converts the image data, determines (binarizes) printing dots in a 2X2 (nXn) matrix according to this digital value, and then stores it in the printer memory 23. be done. This stored dot image is stored in the printer memory 2.
3 to the head driver 24, the print heads 8C18M, 8Y, 8Bk, and 8W are driven, and as a result, a full-color output image is obtained on the recording paper 1.

The black processing unit 33 converts C, M, and Y image data into B.
The process for extracting image data of k is shown in FIG. 5(a).

That is, since equal amounts of C5M5Y are mixed to form the achromatic color Bk, the minimum value discrimination circuit 33a takes the minimum value of the C, M, and Y image data as the Bk image data.

Thereby, the heat extraction process in the minimum value discrimination circuit 33a is expressed as Bk1-m1n (COlMOSYO).

Further, the under color removal (UCR) processing performed by the subtracters 33b, 33c, and 33d to subtract the Bk image data from the C and MSY image data is as shown in FIG. 5(b).

In other words, undercolor removal is CI-CO-Bk1 Ml-MO-Cl- C0-BklMl- It can be expressed as

Next, the reason why W ink is added according to the W image data outputted by the color correction section 34 and the correction of the W and Bk image data by the color correction section 34 will be explained.

That is, the Bk image data extracted by the black processing section 33 is processed by the dot pattern generator 22 at the subsequent stage.
The image data is A/D converted into Bk dot data, but at this time, signal amounts smaller than the image data signal amount corresponding to one ink dot amount are deleted. For example, since Bk in FIG. 5(b) has an ink dot amount of 1.5, it is finally recorded with an ink dot amount of 1.

Therefore, the brightness of the output image is higher than the brightness of the input image. In order to further reduce such differences in brightness, white (W) ink is used for printing.

As described above, this white (W) ink is made of fluorescent whitening dye, and by mixing the W ink with the Bk ink, the density of the Bk ink is reduced.

As a result, the image data signal amount corresponding to one ink dot amount is "D", and the image data signal amount corresponding to the decrease amount of Bk ink corresponding to one W ink dot amount is r D w
(However, rDJ and DwJ are constants determined in advance for each device.) X-quot (Bkl/D) quot; quotient R-
rem(Bkl/D) rem; remainder Y −q u
Calculate ot (R/Dw), and calculate ``If R≧D w J, Bk2-D. If Bk2 and W2 image data are output from the image data of , the difference in brightness can be further reduced.

The color correction section 34 includes a division circuit 4 as shown in FIG.
1.42, multiplication circuit 43.44, comparator 45, analog switch 46.47, and adder 48.49.
50.51.

That is, by dividing Bk and D, the division circuit 41 calculates rX-quot (Bkl/D)quot;
R-rem (Bkl/D)rem; remainder" is calculated. The division circuit 42 calculates rY-q u ot (R/Dw) J by dividing R and Dw.

The multiplication circuit 43 calculates rX-DJ by multiplying X and D. The multiplication circuit 44 calculates "Y-Dw" by multiplying Y and Dw. The comparator 45 compares the R and Dw,
If R≧DwJ, “1” is output, and if rR<DwJ, “0” is output. The analog switch 46 is turned on in response to a signal from the comparator 45.
When it is on, it outputs the supplied rDJ, and when it is off, it outputs "0".

The analog switch 47 is turned on and off according to the signal from the comparator 45, and when it is on, it outputs the supplied "Y-DW", and when it is off, it outputs rOJ, that is, the corrected W. Image data is now output. The adder 48 combines rX-DJ supplied from the multiplication circuit 43 and the analog switch 46.
By adding rDJ or "0" supplied from , corrected Bk image data is output.

The adder 49 is the subtracter 33b, 3 of the black processing section 33.
C and M supplied from 3c and 33d.

By adding the Y image data, corrected C image data is output. The adder 50 adds the C, M, and Y image data supplied from the subtracters 33b, 133c, and 33d of the black processing section 33, and outputs corrected M image data. The adder 51 is the subtracter 33b of the black processing section 33.
By adding the CSM and Y image data supplied from the s33cs33d, corrected Y image data is output. Adder 49.50.5 above
The inputs in 1 are the same data, but the coefficients at the time of addition are matched to the respective corresponding colors.

The color correction by the adders 49, 50, and 51 is performed using a mask that is negative or positive image data (masking).

For example, CD-C1+a11C1+a12Ml+a13YIM low old+a2Lci+a22M1+a23YIYO-Yi
+a31C1+a32Mi+a33Y1.

However, C01M01YO; C, M after color correction.

Y data, Ct, MiSYi CSM before H color correction.

Y data, aij; is a variable.

In addition, by correcting the W image data in the color correction section 34, taking into account the decrease in brightness due to ink bleeding on the recording paper 1 and overlapping ink dots, a decrease in brightness is prevented. It is also possible to do so.

Next, the operation in the above configuration will be explained. For example, right now, R (red), G
(green) and B (blue) image data are supplied to a complementary color conversion unit 31 within the image data processing unit 21. Then,
The complementary color conversion unit 31 converts the supplied R, G, and B image data into cyan (C), magenta (M), and yellow (Y) image data, and outputs the data to the gradation correction unit 32. Thereby, the gradation correction section 32 performs gradation correction on each image data of 01M5Y so that the value of the supplied image data for each color has a linear relationship with the original density, and outputs it to the black processing section 33.

This black processing unit 33 processes black (B k
), extract the image data of Bk, and convert the image data of Bk to C, MS
The same figure (
Convert to 01M, Y, Bk image data as shown in b). As a result, the subtracter 33b in the black processing section 33
, 33c.

33d1 C5M5Y from minimum value discrimination circuit 33a.

Each Bk image data is output to the color correction section 34.

The color correction unit 34 is supplied with C, M, and Y.

Color correction is performed on each image data of Bk to correct turbidity due to unnecessary absorption of ink and decrease in brightness due to color mixture of ink, resulting in C, MSY,
It is converted into Bk5W image data.

That is, the image data of C%M and Y are supplied to adders 49.50.51, respectively, and these adders 49.50.51.
By adding these image data by 50.51, the turbidity due to unnecessary absorption of ink and the decrease in brightness due to color mixing of ink are corrected by the adder 49.50.51.

Y image data is output.

Further, as described above, the adder 48 outputs the Bk image data supplied from the minimum value discrimination circuit 33a, the image data signal amount corresponding to one ink dot amount as "D", and the W ink one dot amount equivalent to "D". Corrected Bk image data is outputted by calculating the image data signal amount corresponding to the amount of decrease in Bk ink by rDwJ, and furthermore, the W image data corrected according to the above data is output from the analog switch 47. Output.

Adder 49.50.51.48 in the color correction section 34,
CSM, Y from analog switch 47.

Each Bk5W image data is output to the gradation correction section 35. This gradation correction unit 35 receives C1M, YSBk,
Tone correction is performed so that the value of each image data of SW and the output image density have a linear relationship, and the data is output to the dot pattern generator 32.

This dot pattern generator 22 performs A/D conversion on the image data whose gradation has been corrected by the gradation correction section 35, and determines (binarizes) printing dots in a 2×2 matrix according to the digital values. It is output to the printer memory 23 and stored in this printer memory 23. This stored dot image is stored in the printer memory 23.
from there to the head driver 24.

As a result, drive signals from the head driver 24 are transmitted to the flexible cables 14C and 14M.

14Y, 148, the above print head 8C via 14W
, 8M, 8Y, 88, and 8W. Therefore, print heads 8C, 8M, 8Y.

88 and 8W are respectively driven according to corresponding drive signals, and the corresponding inks CSM and YSBk.

W is discharged. As a result, a full-color output image is obtained on the recording paper 1.

As mentioned above, in addition to the four color inks of C, M, Y, and Bk, W ink is used, and the W image data for this W ink is generated from the image data processing section, so the ink It is possible to correct the decrease in brightness due to color mixture, and also to change the brightness, making it possible to express bright colors and pale colors, and improving the color reproducibility of output images.

[Effects of the Invention] As detailed above, according to the present invention, it is possible to provide a recording apparatus that can obtain an output image with sufficient color reproducibility.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a block diagram showing the general configuration of a recording device, FIG. 2 is a perspective view showing the configuration of the main parts of the recording device, and FIG. 3 is an image data processing diagram. FIG. 4 is a block diagram showing the configuration of the color correction section. FIG. 5 is a diagram showing image data for each color to explain black extraction and undercolor removal in the black processing section. ,
FIG. 6 is a diagram showing an example of image data output from the color correction section. 1... Recording paper (recording medium), 8C, 8M, 8Y. 88, 8W...print head, 16C, 16M. 16Y, 168, 16W... ink tank, 20.
...Image data input unit (image data input means), 211
．． , image data processing section (image data processing means), 34.
・・Color correction section, 41.42 ・・Division circuit, 43.44
...j [circuit, 45... comparator, 46.47
・・・Analog switch, 48.49.50°51...
・Adder. Applicant's agent Patent attorney Takehiko Suzue Figure 2

Claims (1)

[Scope of Claims] Image data input means for inputting image data; image data processing means for outputting cyan, magenta, yellow, black, and white image data from the image data from the image data input means; 1. A recording apparatus comprising: recording means for ejecting ink of a corresponding color onto a recording medium in accordance with image data of each color from an image data processing means.