JPH04259566A - Printing method of ink jet printer - Google Patents

Abstract

PURPOSE:To obtain an excellent printing image by controlling bleeding and variation in a color tone in an ink jet printer. CONSTITUTION:Printing of a (2n-1)th nozzle, when n is a positive integer, is performed by a going scanning of a carriage 9 for a plurality of nozzles of each printing head 8. Printing of a 2n-th nozzle is performed by a returning scanning. Printing of all nozzles is completed by the going and returning scanning. Printing density for one time scanning can be reduced to one half.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing method for an ink jet printer having a plurality of ink discharge ports.

0002

2. Description of the Related Art In a conventional ink jet printer having a plurality of ink ejection ports, print dots corresponding to all the ink ejection ports are printed in one scan. Therefore, ink smears occur in areas with a large amount of ink,
This caused a drop in image quality.

[0003] Furthermore, when full-color back-and-forth printing is performed with a carriage type printer, the order of overlapping colors is reversed between forward and backward printing, causing a change in color tone between forward and backward printing, which significantly degrades the image quality. I had dropped it.

0004

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and provides a printing method with less bleeding and less noticeable change in color tone even in full-color reciprocating printing. The purpose is to

[0005]

Means for Solving the Problems The present invention provides a printing method for an inkjet printer having a plurality of ink ejection ports, in which printing dots corresponding to all the ink ejection ports are printed by multiple scans. According to a second aspect of the present invention, it is possible to distinguish between printing of line drawings and characters and printing of color images, and when printing line drawings and characters, all ink ejection ports are covered in one scan. It prints print dots, and when printing a color image, it prints print dots corresponding to all the ink ejection ports in multiple scans.

[0006] In a carriage type inkjet printer, it is possible to perform printing with odd numbered nozzles or even numbered nozzles in the first scan, and print with the remaining nozzles in the second scan.

[0007] In a drum type inkjet printer, it is possible to perform printing with odd numbered nozzles or even numbered nozzles in the first scan, and print with the remaining nozzles in the second scan.

[0008]

[Operation] The present invention is a printing method for an inkjet printer having a plurality of ink ejection ports, in which print dots corresponding to all the ink ejection ports are printed by multiple scans. Therefore, the print density of print dots in one scan can be reduced to one of the print density in multiple scans.

For example, in the previous scan, printing was performed using the odd-numbered nozzle, and in the backward scan,
When printing is performed using even-numbered nozzles, the printing density in each scan is halved.

[0010] Therefore, in areas with a large amount of printing,
The amount of ink applied to the recording paper for each scan can be reduced, and bleeding can be suppressed.

Furthermore, as a matter of course, due to the time difference between the back and forth scans, the ink printed in the previous scan will dry more quickly, and bleeding can be suppressed.

[0012] The problem of color overlapping is also reversed between forward and backward, but because they are mixed, the change in color tone is not noticeable.

[0013] The printing area of one scan is divided into two areas: forward and backward.
Not only when printing is divided into multiple times, but when printing is divided into multiple times, problems such as bleeding and overlapping colors can be avoided.
It can be made more discreet.

[0014] It distinguishes between printing line drawings and characters and printing color images, and when printing line drawings and characters, prints dots corresponding to all the ink ejection ports in one scan, and when printing color images, prints multiple dots. By printing print dots corresponding to all ink ejection ports in one scan, it is possible to improve the overall printing speed.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic diagram of an example of an inkjet printer to which the inkjet printer printing method of the present invention is applied. In the figure, 1 is an interface circuit, 2
3 is a buffer memory, 3 is a mode switching mechanism, 4 is a control circuit, 5 is a print head drive circuit, 6 is a carriage operation control circuit, 7 is a paper feed operation control circuit, 8 is a print head, 9 is a carriage, 10 is a carriage drive motor,
11 is a carriage drive belt, 12 is a platen roll,
13 is a paper feed drive motor.

The interface circuit 1 is for exchanging electrical signals with the outside, and print signals taken in from the interface circuit 1 are stored in a buffer memory 2. In this embodiment, the buffer memory 2 stores image data for one scan. The mode switching mechanism 3 selects and determines whether to print all print dots in one scan or print all print dots in multiple scans, and inputs a selection signal from an operation unit (not shown). Alternatively, the print data may be determined by a CPU (not shown). Based on the signal from the mode switching mechanism 3, the control circuit 4 performs the following operations as described below.
Masking is performed on the printed dots. As the print head 8, a head 8 having a plurality of ink ejection ports is used. A plurality of rows of print heads having a plurality of ink ejection ports in one row may be used, and each row may correspond to a different color ink. In this case, the plurality of print heads are mounted on a carriage 9, and are driven by a carriage drive motor 10 and a carriage drive belt 11.
Printing is performed while scanning in the direction of the generatrix of the platen roll 12.

FIG. 2 is a block diagram of an example of a control circuit for masking printed dots. For the sake of simplicity, the description will be made assuming that the number of ink ejection ports in one row of print heads is eight. In the figure, V1 to V8 are image data,
M1 to M8 are mask bit data, G1 to G8
is an AND gate, P1 to P8 are output terminals, and signals from the output terminals P1 to P8 are input to the print head driving circuit. Image data V1 to V8 are AN
Since the voltage is applied to one terminal of the D gates G1 to G8 and the mask bit data M1 to M8 are applied to the other terminal, among the image data V1 to V8, in addition to the gate with mask bit data of 1, Only the image data that has been input is output to the output terminal, and the corresponding print bits are printed.

First, if the mode is selected to print all print dots in one scan, or if the mode is set to print character parts separated by pictograph separation in one scan, then the image shown in FIG. Mask bit data M1 to M8 are all 1, and all print dots are printed in one scan, similar to a conventional inkjet printer.

Next, the operation in a mode in which all print dots are printed by multiple scans will be explained. For one scan area, all print dots are printed in two scans, and this is achieved by reciprocating printing, in which the print dots corresponding to odd number nozzles are printed in the past, and the print dots corresponding to even number nozzles are printed in the return. The case of printing dots will be explained.

The control circuit 4 reads out data from the buffer memory 2, and in the past, mask bit data M1
, M3, M5, and M7, the odd number is set to 1. For example, if the image data V1 to V8 are 1 for nozzle numbers 1, 2, 5, 6, 7, and 8 as shown in FIG. and the 1st, 5th, and 7th nozzles are driven. At the time of recovery, mask bit data M2, M4,
Since the even number of M6 and M8 is 1, Figure 3 (B)
The nozzles with nozzle numbers 2, 6, and 8 are driven as shown in FIG. That is, according to the mask bit data M1 to M8, odd-numbered image data is transferred to the print head drive circuit in the past, and odd-numbered image data is transferred to the print head drive circuit in the return. That is, the control circuit 4 reads data from the buffer memory 2 twice, once in the forward direction and once in the backward direction, and all print dots in the nozzle arrangement direction are printed by scanning back and forth.

The control circuit 4 sends a signal to the paper feed operation control circuit 7 to stop paper feeding until the reciprocating printing is completed, and after the reciprocating printing is completed, the paper is fed.

In reciprocating printing in a mode in which all print dots are printed in one scan, the paper is fed after the forward and backward printing is completed.

FIG. 4 illustrates the appearance of printed dots when solid printing is performed. This explanation will also be made assuming that the number of ink ejection ports in one row of print heads is eight. Note that the arrow in the figure indicates the scanning direction of the carriage, that is,
Indicates the printing direction.

The figure (A) shows a mode in which all print dots are printed in one scan. Although the previous printing dots are illustrated, the same applies to the backward printing.

Figures (B) and (C) are examples of multiple scanning, and are in a mode in which all print dots are printed by reciprocating printing. (B) shows the printed dots in the past, and in this case shows how the dots were printed by odd-numbered nozzles. In the case of return, the illustration shows part way, but since printing is performed in even-numbered nozzles,
The gaps between the previously printed dots are filled, and all printed dots are printed by reciprocating printing.

In the printing explained with reference to FIG. 4, the nozzles used for printing are always the same during forward and backward operations. That is,
The nozzles used for printing do not change within one scan.

FIG. 5 shows an embodiment in which printing dots are masked so that the nozzle used for printing changes within one scan. In this example, 1 in the scan direction.
Odd-numbered and even-numbered nozzles print alternately for each dot. Therefore, in previous scans, print dots are selected in a staggered manner. In the backward scan, the odd-numbered and even-numbered nozzles print alternately so as to fill in the spaces between the dots printed previously, and all printed dots are printed by reciprocating printing.

In the above-mentioned embodiment, the number of ink ejection ports is eight, but the number of ink ejection ports is not limited to eight, and any number of ink ejection ports may be used. good. In addition, we have explained a mask that prints the print dots corresponding to odd number nozzles in the past and even number nozzles in the return, but it is also possible to use even number nozzles in the former and odd number nozzles in the return, as shown in Fig. 5. To,
The nozzle to which a mask is applied may be changed within one scan.

[0029]

As is clear from the above description, according to the present invention, better image data with less blurring can be obtained compared to the conventional method of printing all print dots in one scan.

Furthermore, unlike conventional reciprocating printing, a good image can be obtained with very little change in tone due to differences in the order of overlapping colors.

[0031] Whether all print dots are printed in one scan,
By providing a mode switching mechanism that determines whether to print all print dots in multiple scans, in the case of characters and line drawings, all print dots can be printed in one scan as in the past, resulting in faster printing speeds. It also has the effect of not dropping as much.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of an example of an inkjet printer to which a printing method for an inkjet printer of the present invention is applied.

FIG. 2 is a block diagram of an example of a control circuit that masks printed dots.

FIG. 3 is an explanatory diagram of the printing operation in FIG. 2;

FIG. 4 is an explanatory diagram of printing dots when solid printing is performed in the embodiment.

FIG. 5 is an explanatory diagram of printing dots when performing solid printing in another embodiment.

[Explanation of symbols]

1 Interface circuit 2 Buffer memory 3 Mode switching mechanism 4 Control circuit 5 Print head drive circuit 6 Carriage operation control circuit 7 Paper feed operation control circuit 8 Print head 9 Carriage 10 Carriage drive motor 11 Carriage drive belt 12 Platen roll 13 Paper feed drive motor

Claims (2)

[Claims] 1. A printing method for an inkjet printer having a plurality of ink ejection ports, the method comprising: printing dots corresponding to all the ink ejection ports in a plurality of scans. 2. In a printing method for an inkjet printer having a plurality of ink ejection ports, printing of line drawings and characters is distinguished from printing of color images, and when printing line drawings and characters, all ink ejection ports are printed in one scan. A printing method for an inkjet printer, characterized in that when printing a color image, printing dots corresponding to all ink ejection ports are printed in multiple scans.