JP3070352B2 - Print processing method of inkjet recording device - Google Patents

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 apparatus which prints on recording paper by ejecting ink droplets from a discharge port of a recording head, whereby high quality printing can be obtained at a seam between printing lines. It relates to a print processing system.

[0002]

2. Description of the Related Art In an ink jet recording apparatus, a recording head has n ink droplet discharge nozzles, prints n dots in a recording paper feed direction (sub-scanning direction), and prints main dots orthogonal to the sub-scanning direction. M dots are printed in the scanning direction, and n
Xm dot matrix is printed on the first line, and then the recording paper is fed in the sub-scanning direction, and the recording head is scanned in the main scanning direction to print on the second line, and so on. There is a method of sequentially printing the third line.

In the recording apparatus, it is difficult to transfer the recording paper with the same precision as the resolution of the recording head, and there is a problem that the print quality at the joint between adjacent rows is inferior. That is, if the dot at the bottom of a printed line and the dot at the top of the next line are too overlapped, the density of that portion will increase and black streaks will appear at the seam. If the dot spacing is too large, white streaks will appear at the seams. Adjusting the dot interval with high precision is limited by mechanical precision and the influence of expansion and contraction of the recording paper due to temperature and humidity.

Therefore, techniques for solving the above-mentioned problems have been conventionally proposed. For example, JP-A-55-4283
According to Japanese Patent Publication No. 6 (A) -6, as shown in FIG.
Are overlapped by at least one dot, and in the overlapped seam portion 50, the dots arranged in the odd-numbered columns are printed at the time of printing the row A (50a), while the dots arranged in the even-numbered columns are printed in B. This is performed at the time of printing a line (50b). Although this method can improve the printing quality as compared with the printing method having no seam, the regular dot arrangement in the row direction is performed at the seam 50,
Black streaks and white streaks appear at the boundary of the joint 50,
There is a drawback that band-like black streaks and white streaks appear in the seam portion 50.

Therefore, in Japanese Patent Laid-Open Publication No. Hei 2-62243, as shown in FIG. 7, an area 52A printed by a first recording head 52A and an area 52B printed by a second recording head 51B are overlapped. In the joined and overlapped seam portion 52, the dots 51a in the X direction
The border between the dots and the dots 51b is arranged so as to be random in the Y direction, so that black streaks and white streaks do not appear at the joints 52.

[0006]

By the way, as shown in FIG. 2, a plurality of inks of a plurality of colors (for example, cyan, magenta, yellow and black inks) are supplied from a plurality of recording heads 16.
In the ink-jet recording apparatus which discharges the recording head 16 in the X direction, the recording head 16 is driven on the recording paper 15 to record the recording head width. Then, the recording paper is transported in the Y direction by the width of the recording head in preparation for the next printing. As described above, it is difficult to transfer the recording paper 15 with the same precision as the resolution of the recording head, and an error of ± occurs.
As shown in FIG. 2A, white streaks are generated and the image quality is significantly deteriorated. Therefore, as shown in FIG. 2B, a design is usually made such that the seam portions R between the printing lines slightly overlap each other. You. However, in the case of such a design, although the printing is normally performed in the single color solid (100%) printing region S, the joint portion of the composite color red, green, and blue regions P formed by combining the ink is formed. There is a problem that black streaks occur at R '.

SUMMARY OF THE INVENTION The present invention solves the above-described problem. In an ink jet recording apparatus having a plurality of recording heads for discharging a plurality of color inks, a black streak or a white line generated at a seam between print lines is provided. It is an object of the present invention to provide a printing processing method which makes streaks inconspicuous and enables high-quality printing.

[0008]

For this purpose, the printing method of the ink jet recording apparatus of the present invention comprises a plurality of recording heads for ejecting inks of a plurality of colors, respectively, in a direction orthogonal to a print line printed on a recording medium. Each recording head has a plurality of ink droplet discharge nozzles, and the recording head is moved in the direction of a print line on the recording medium to perform printing for one line. Means for determining the presence of a composite color at a seam between printed lines in an ink jet recording apparatus that performs relative printing to print the next line, and ink droplets at a seam between the printed lines when there is a complex color Means for performing a process of partially thinning out the ink discharge for one nozzle of the discharge nozzle. The existence of the composite color is determined based on whether or not the printing by the nozzle for performing the partial thinning process and the printing by the nozzles before and after the nozzle are both composite colors.

[0009]

According to the present invention, in the red, green, and blue regions of the color formed by combining the inks, the joint dots between the printing lines are controlled, so that the generation of streaks at the boundary portions is inconspicuous. And high quality images can be obtained.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing an example of an ink jet recording apparatus to which the present invention is applied, and FIG. 2 is a view for explaining a seam between print lines.

In FIG. 1, a head carriage 2 is slidably mounted on two guide rails 1, and the head carriage 2 is connected to a head carriage driving motor 4 via a timing belt 3. The head carriage 2 has four color ink jet cartridges 5C, 5M, 5C for cyan, magenta, yellow and black.
Y, 5K are attached. These ink cartridges are detachably mounted on the head carriage 2 by the lock lever 6.

Each ink jet cartridge 5C, 5C
The recording head 16 shown in FIG.
Is provided. The recording head 16 has, for example, 30
It has a resolution of 0 dpi and has 128 ink droplet ejection nozzles in the sub-scanning direction Y. The recording head discharges ink droplets using thermal energy,
An electrothermal converter for generating the energy,
By the subtractive color mixing method using multiple recording heads and ink,
Red, green, and blue are formed by combining cyan, magenta, yellow, and black inks, and a multicolor image corresponding to input image information is printed on a recording medium.

Each ink jet cartridge 5
An ink tank 7 for supplying ink to the recording head is built in C, 5M, 5Y, and 5K, and a driving signal is transmitted to the recording head 16 by a power supply / signal cable 8. A feed roll 9 and an exit roll 10 are disposed between the two guide rails 1 in parallel with the guide rail 1. The feed roll 9 and the exit roll 10 are
Paper feed motor 1 via gears 11 and 12 and belt 13
4.

In the ink jet recording apparatus configured as described above, the recording on the recording paper 15 is performed by driving the recording head 16 while moving the head carriage 2 on the recording paper 15 in the X direction, and by driving the recording head 16 by the recording head width. Recording is performed, and the recording paper 15 is moved in the Y direction by the width of the recording head in preparation for the next printing. FIG. 2 shows this state. As described above, it is difficult to transfer the recording paper 15 with the same precision as the resolution of the recording head. 2), white streaks are generated and the image quality is significantly deteriorated. Therefore, as shown in FIG. 2B, the design is usually made such that the seam portions R between the print lines slightly overlap each other. However, in the case of such a design, although the printing is normally performed in the single color solid printing (ejection from all nozzles) area S, the composite color red, green, and blue areas P formed by combining the inks are formed. Black streaks occur at the joint R '.

Next, the print processing method of the present invention will be described with reference to FIGS. FIG. 3 is a flowchart showing one embodiment of the print processing system of the present invention, FIGS. 4 and 5 are dot pattern diagrams showing the print processing system of the present invention, and FIG. FIG. 4 shows a case before the printing process is performed.
(B) shows the case where the printing process of the present invention is performed.

In FIG. 3, first, in step S1, it is determined whether or not the 128th nozzle (final nozzle) in the previous scan is a composite color, and in step S2, it is determined whether or not the first nozzle in the current scan is a composite color. Then, in step S3, it is determined whether or not the second nozzle in the current scan is a composite color. If it is determined in steps S1 to S3 that the color is a composite color, it is within the range of X1 shown in FIG.

Next, in step S4, it is determined whether the 128th nozzle in the previous scan and the first nozzle in the current scan are at the same position. This is because the output pattern shown in FIG.
It is determined whether there is data at the eighth nozzle. When all the conditions of steps S1 to S4 have been observed, in step S5, the data of the first nozzle in the current scan is thinned out. This process is shown in FIG.
As shown in FIG. 5B and FIG. 5, data of the first nozzle in the range of X1 is thinned out so as not to eject ink for each nozzle.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible. For example, in the above embodiment,
Although the recording paper is moved in the sub-scanning direction, the recording head may be moved in the sub-scanning direction with the recording paper fixed. Further, in the case of recording paper having a large bleeding characteristic (for example, plain paper), switching between valid / invalid by an instruction is performed, the number of print dots at the seam between print lines is reduced, and bleeding is suppressed. The generation of muscle may be improved.

[0019]

As is apparent from the above description, according to the present invention, the secondary color red formed by compounding the ink,
In an ink jet recording apparatus having a plurality of recording heads for discharging a plurality of color inks in green and blue regions, black streaks and white streaks generated at a seam between print lines are made inconspicuous, and high quality printing is obtained. Can be.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating an example of an inkjet recording apparatus to which the present invention is applied. FIG. 2 is a diagram for explaining the printing process by the recording head. FIG. 1 is a schematic configuration diagram of a color inkjet recording apparatus to which the present invention has been applied.

FIG. 2 is a diagram for explaining a seam between print lines in the ink jet recording apparatus.

FIG. 3 is a flowchart showing one embodiment of a print processing system of the present invention.

4A and 4B are dot pattern diagrams showing a print processing method of the present invention. FIG. 4A shows a case where the print processing of the present invention is not performed, and FIG. 4B shows a case where the print processing of the present invention is performed. Shows the case.

FIG. 5 is a dot pattern diagram showing a print processing method of the present invention.

FIG. 6 is a diagram for explaining an example of a conventional print processing method at a seam.

FIG. 7 is a diagram for explaining an example of a conventional print processing method at a seam.

[Description of Signs] 1 ... guide rail, 2 ... head carriage 5C, 5M, 5Y, 5K ... ink cartridge, 15 ...
Recording medium 16: recording head, X: main scanning direction, Y: sub-scanning direction,
L1 to L4: printing line R, R ': seam, S: single color, P: composite color, X1: thinning range in X direction

Claims (3)

(57) [Claims] A plurality of recording heads for discharging a plurality of color inks; and a plurality of ink droplet discharge nozzles arranged on each recording head in a direction orthogonal to a print line to be printed on a recording medium. An ink jet recording apparatus that moves the recording head in the direction of a printing line on a recording medium to perform printing for one line, and then relatively moves the recording medium and the recording head to perform printing on the next line. Means for determining the presence of a composite color at a seam between print lines, and means for partially thinning out the ink ejection of one ink droplet ejection nozzle at the seam between the print lines when there is a complex color A print processing method comprising: 2. The method according to claim 1, wherein the presence of the composite color is determined based on whether or not the printing by the nozzle performing the partial thinning process and the printing by the nozzles before and after the nozzle are both composite colors. The print processing method according to claim 1. 3. The multi-color ink according to claim 1, wherein the plurality of inks are cyan, magenta, yellow, and black, and a composite color formed by combining the inks is red, green, and blue. Print processing method.