JPS59212271A - Correction between printing heads - Google Patents

Abstract

PURPOSE:To enable to easily perform correction between heads, by a method wherein transfer of a printing signal to each printing head is delayed by a respectively predetermined period of time behind that for the foremost printing head by a micro-computer, and images are overlappingly printed at a point, in a color printer. CONSTITUTION:When a one-line amount of data are fed from a host through an interface 15, the printing data are momentarily stored into an RAM12 by a CPU 10. Then, the CPU10 transfers the printing data to an interface 17 to determine a printing position first. For example, the printing position is determined by counting time after the start of printing by a timer function of the CPU10, by using slits or by other similar means, and correction quantities between the heads are calculated for each printing position. Printing data are formed by delaying data for the heads M, C, K behind data for the foremost head Y in the case of forward printing, while delaying the data for the heads C, M, Y behind the data for the foremost head K in the case of backward printing, and printing is sequentially conducted for each predetermined period of time. Accordingly, correction between the heads in a both-direction printer can be easily performed.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention uses a plurality of print heads, for example, four print heads, and prints, for example, yellow, magenta, cyan, and black ink droplets from these print heads onto a recording medium. The present invention relates to a method of correcting print heads for color printing by sequentially printing at one point.

Previously, in an inkjet recording device that prints a single point by ejecting ink droplets from multiple inkjet heads,
It has been proposed that a RAM is used as a delay element for the print signal, a preset counter is used as the address counter of this RAM, and the delay amount of the print signal is changed by changing the preset value. Delays are possible in the case of printing, but difficult in the case of bidirectional printing. For example, as shown in Fig. 1, in the forward direction, with the Y (yellow) head as the reference, the M (magenta) head is set at DLF1, and the C (cyan) head is set at DLF1 by delay elements 1 and 2°3.
F2. The K (black) head must be delayed by DLF3, and in the opposite direction, the C head must be delayed by DLRl, the M head by DLR2, and the Y head by DLR3 using delay elements 4 and 5°6. , M heads, and since DLRI is a complementary IF between C heads, it is difficult to set DLFI=DLR+ in terms of manufacturing the delay element.

OBJECTS The present invention has been made in view of the above circumstances, and an object of the present invention is to perform correction between each head of a bidirectional printing device that performs color printing to avoid oil stains by using a microcomputer.

Order--1 The configuration of the present invention will be described below based on examples.

FIG. 2 is a principle diagram showing the method of correcting between print heads according to the present invention. The distance between each head is determined based on the Y (yellow) head, and when printing in the forward direction, the distance between the Y (yellow) and M print heads is determined.
(magenta), C (cyan), and K (black), set the head delay amount to M, C, and Y heads in the order of DL.
F, = ZHYM (29) ± αM, DLF2 = ZHY
Cl:58) ± αc, D L F 3 =
Z HY K (87) ±a When printing in the reverse direction, set C, M, Y to the head.
The delay amount of each head is DLRI = DLF3 - DLF.
2, DLR2=DLF3-DLFI, DLR3=D
LF3 is determined and the print signal is delayed by this amount. For this purpose, a microcomputer (l-chip CPU, such as Intel 8041A, 8042, etc.) is used to sequentially store the print data in internal RAM, read the data according to the forward direction and reverse direction, and print the data from the head for each print position. Compensate for the delay between
E and print.

Figure 3 is a block diagram for implementing the present invention, where IO is the main CPU, 11 to 13 are memories, and 11 is FROM.
, 12 is a data buffer, 13 is a character generator, 14 is a data bus, and 15 to 17 are interfaces, in which 15 transfers print signals, 16 controls the scanning motor, etc., and 17 controls printing such as printing position. There it is again. Now, when 1547 worth of data is sent from each host via the interface 15, the CPU 10 transfers it to the interface 17L as print data and first determines the print position. For example, the timer function of the CPU measures the time from the start of printing to determine the printing position, or the printing position is determined by using a slit. And what about the supplementary IF between each print position? As shown in the flowchart in Figure JJJ4, print data for each head is created by performing these calculations.

The flowchart in Fig. 4 measures the time with a timer, determines the printing position, reads out the data for each Y1M, C, and when the printing direction is the positive direction (this lf, the D shown in Fig. 2).
Create print data by delaying data to M, C, by LFl, DLF2, and DLF3, and if the printing direction is reversed, calculate DLRl, DLR2, and DLR3 to create print data for each C, M, and Y. This indicates that the data will be created and printed sequentially.

Place-m-! As mentioned above, according to the present invention, a microcomputer is used to perform corrections between print heads, which simplifies the circuit configuration compared to conventional methods and also supports bidirectional printing. can.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the conventional correction method between print heads, Figure 2
3 is a diagram showing a correction method between print heads according to the present invention, FIG. 3 is a block diagram for implementing the present invention, and FIG. 4 is a flowchart. 10...CPU, 11-13...Memory, 14...
- Data bus, 15-17...interface.

Claims (2)

[Claims] (1) In a recording device that prints by overlapping ink droplets from multiple print heads at one point, the print signal is temporarily stored in the RAM area of the microcomputer, and the print signal is transferred to each print head at the beginning. A method for correcting print heads, which is characterized in that printing is performed by overlapping each other at one point by delaying each print head by a predetermined time. (2) In a bidirectional printing recording device that prints by overlapping ink droplets from multiple print heads, the print signal is temporarily stored in the RAM area of the microcomputer and sent to each print head relative to the first head. A correction method between print heads characterized by setting each delay time of the signal transfer according to the printing direction and printing by overlapping each other at one point.