JPS5887064A - Reciprocatory dot print position control system - Google Patents

Abstract

PURPOSE:To prevent the deviation of print position of reciprocatory printing by such an arrangement wherein a set of delay circuits is to be commonly used for reciprocatory movement, and the amount of delay of information to be impressed to print heads other than those heads positioned at both ends of a group of ink jet heads is to be independently varied for going and returning of a carriage at the time of reciprocatory movement. CONSTITUTION:In a serial printer which performs printing both ways of the reciprocatory movement of its carriage on which 3 ink jet heads are arranged in its moving direction, at the time of going of the carriage, in relation to the print position of the top head, the print position of No. 2 head is determined by the change-over of a digital switch 6a, and further the print position of No. 3 head is determined by the change-over of a digital switch 6b. On the one hand, at the time of returning of the carriage, in relation to the print position of the top head, the print positions of No. 2 and No. 3 heads are determined by digital switches 5a, 5b. Consequently, print positions can be independently determined, being separated from the print positions of the going trip, and it becomes possible to make records free from deviation of print position even if a top head is changed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a print dot position control method for a print head that moves back and forth, and in particular, three or more ink jet heads are arranged in a straight line in the direction of movement of a carriage to print on both the outward and return passes. The present invention relates to a printing dot position control method in a printer that performs printing.

In conventional serial printers, especially serial printers using inkjet heads, in order to perform multicolor printing or simultaneous printing of multiple lines in the same color, the print head must be set in a straight line as shown in Figure 1 a or b. The structure is such that it is placed in In the figure, 1 is for inkjet.

2 is a head installation stand, 3 is an ink ejection port, and 4 is a recording paper. In this configuration, the head 1 is moved relatively in the horizontal direction etc. are recorded in multiple colors or in a single color.

However, in the gutter arrangement shown in FIGS. 1a and 1b, the size and shape of the head 1 or the head 1 and the recording paper 4
If it is impossible to arrange the heads 1 so that the spacing between them is the same as the printing density due to the distance between the print dots, for example in a Stemme type head, the printing dots will be misaligned.

If the head arrangement shown in Figure 1a is arranged at a certain inclination angle θ with respect to the main scanning direction However, the head spacing in the main scanning direction X hardly changes, and as a result, the printed dots are shifted in the main scanning direction X as in the case of & in FIG.

As a measure against dot misalignment caused by this spatial curvature, a temporal compensation term has conventionally been added to prevent positional misalignment.

In other words, the time term of the main scanning speed corresponding to the spatial curvature is converted by the above-mentioned number of pulses using pulses synchronized with the print position clock, and the print image signal is stored in a shift register or RAM (random access memory). The delay prevents the printing position from shifting. Therefore, in printing with the head arrangement shown in FIG. 3, head 2 is operated with a delay of 11 minutes (actually the number of pulses corresponds to el, but it will be expressed as 11 below) with respect to the leading head 1. Then, with a delay of β2 minutes, head 3 is activated, and finally head 4 is activated.
By operating the head 1 at a timing delayed by β3 minutes from the head 1, characters or figures can be printed on the recording paper 5 without any misalignment of the printing position. However, if the head arrangement shown in FIG. 3 is used to perform both forward and backward printing operations, a new problem arises. In other words, in the head arrangement shown in Fig. 3, the first head during forward printing is head 1.
The last head is head 4. This is reversed when printing on the return path, and head 4 becomes the first head and becomes the last head, head 1. Therefore, the reference head for printing changes, and the setting of the delay amount in the forward path does not necessarily match the delay amount in the backward path. The delay amount of the last head, ie, the delay amount other than .beta. in the example of FIG. 3, does not necessarily match the delay amount set in the return pass and the printing delay amount in the outward pass. The reason for this is related to the manufacturing precision of the head, the precision of mounting the head to the movable table, and the method of forming characters or figures. As shown in Figure 4, the deviation in head manufacturing accuracy is due to the positional deviation from both ends of the head body to the ink ejection port 1,
Furthermore, oblique discharge is related to the internal structure and the like. The accuracy of mounting on a moving table cannot be said to be sufficient because, considering the maintainability of the head, it is better to make the precision a few degrees rougher so that it can be easily attached and detached. Furthermore, when printing characters etc. with the head arrangement shown in FIG.
The misalignment of each printing dot requires much higher printing position accuracy than when printing one character in one scan.

The present invention provides a new method for preventing the displacement of the reciprocating dot printing position caused by the above-mentioned drawbacks in an apparatus that prints characters, figures, etc. with multicolor or single-color ink by reciprocating the head arrangement shown in FIGS. 1a and 2. This provides a control method. An embodiment of the present invention will be described in detail below. 6th
The circuit shown in the figure represents one embodiment of the present invention. The signals that have passed through both signal power lines 10 are input to gates 1a and 1b, and these gates distinguish reciprocating motion into blocks that pass only on the outward journey (Gate Ia side) and blocks that pass only on the return journey (Gate Ib side). It is divided by signal 11. gate 1
The signal output from &, 1b is input to gate 10,
At this gate, the signal applied to the first head is sent to 1C-1, the signal applied to the second head is sent to 1C-2, and the signal applied to the third head is sent to 1C-1, regardless of whether it is on the forward or return trip. 6, the signals applied to the fourth head (in this example, the last head) are respectively input to 1C-4. Therefore, the signal applied to the leading head during the forward trip is
0-1, but on the return trip, the signal is applied to the last node, so it will be input to gate 1C-4.

The same applies to other gates. Gate 1C-2, I
Each signal output from C-3 and IC-4 is input to a delay circuit such as a shift register, FtAM, counter, etc. In the embodiment shown in FIG. 5, shift registers 2a and 2b are used as delay circuits.
, 2C, 2d, 3! L.

3b and 3c, and a pulse generated in proportion to head movement displacement is used as a delay clock to be applied to the signal line 9. Since the output of gate 1C-1 is a signal to be applied to the leading head, it does not pass through the delay circuit.

However, it is possible to use the delay circuit 2d for the purpose of shifting the entire printing start point. The delay circuits 3a, 3b, and 3c have a circuit configuration in which the amount of delay can be preset.

Delay 1 variable data to be manually inputted to the delay circuits 3a, 3b is manually inputted from the selectors 4a, 4b. Furthermore selector 4
The inputs of a and 4b are two independent digital switches 5a and 6a with a 4-bit configuration.

6b and 6b are connected. This digital switch may be any other equivalent circuit, such as a dip switch or a normal 0N-OFF switch.If the delay amount is still large, the delay variable take can be changed from a 4-bit configuration to a 5-bit or 6-bit configuration. All you have to do is increase the configuration. Digital switches 6a, 5b, 61
．． 6b is the shift register 3a during the forward movement due to the reciprocating motion discrimination signal 11 manually input to the selectors 4a and 4b.
.

3b, and on the return trip, 5ilL and 5b similarly influence each other.

As a result, to align the print position during the forward pass, the print position of the second head is determined by switching the digital switch 61L to the print position of the head gutter, and then the printing position of the second head is determined.
The printing position of the third head is determined by switching the digital switch 6b. On the other hand, the positioning of the leading hexagon during the return trip is performed using digital switches 5a, 5k). Therefore, it is possible to set the print position separately and independently from the print position alignment during the forward pass.

Therefore, even if the leading reference head used to determine the print position is changed in the forward and return passes, it is possible to record without any deviation in the print position.

On the other hand, the amount of delay from the last head to the first head is
Since <lj=l as shown in FIG. 3 holds regardless of the return path, a selector circuit corresponding to circuits 4a and 4b shown in FIG. 6 is not required. Therefore, only a single delay amount correction digital switch T is input to the shift register 3C. The image signals output from the shift registers 2d, 3a, and 3b are input to the selector 8. This selector 80
The function is to input the signal input to the image signal input line 10 to the game 1-1.
A, 1B can be returned by the scanning movement direction, that is, by the reciprocating motion discrimination signal. With the above-described delay circuit configuration and signal control, the timing of ink ejection is adjusted while printing is performed with respect to the reciprocating movement of the head, while changing the delay amount data so that there is no dot misalignment on the recording paper -1-. Therefore, according to the present invention, a printer head group of a type in which it is impossible to arrange a plurality of heads of three or more along a moving path and to make it impossible to align the intervals between the plurality of hens to the same density as the printing density. In the forward path of the delay circuit,
In order to share the information on the return trip, and to share the information applied to the print heads other than the print heads located at both ends in the reciprocation, the information is shared on the return trip.
It is possible to delay the printing by setting independent printing timing on the return trip. As a result, it is possible to reduce the factors that affect the manufacturing accuracy of the head, correct ink ejection failure (oblique ejection operation), improve maintainability by reducing the accuracy of the moving table, and economically configure the control circuit. .

[Brief explanation of the drawing]

119a and 119b and FIG. 2 are diagrams showing an example of print head arrangement, and FIG. 3 is a diagram showing print heads arranged in a straight line in the main scanning movement direction, with respect to the leading head on the forward path 0 and the backward path in the scanning movement direction. FIG. 4 shows the position of the ink ejection ports relative to the end of the head body in a single print head; FIG. 5 shows an embodiment of the reciprocating dot print position control method according to the present invention. It is a block diagram. 1a, 1b, 10-1. IQ-2, IC-
5,1 cm---Gate, 2a, 2b, 2Q
, 2d-.=shift register, 3a, 3b, 3C...
・Shift register with preset delay amount, 4a, 4
b, 8...Selector. 5a, 5b, 6a, 6b, 7...Digital switch, 9...Position pulse generated in proportion to main scanning movement displacement, 10...Picture signal input line, 11... ...Reciprocating motion determination signal. Name of agent: Patent attorney Toshio Donakao and one other person Figure 1 Showa 5'' Figure 3 Figure 4

Claims (1)

[Claims] It has an inkjet head group in which three or more mutually independent inkjet heads are arranged in the horizontal movement direction, and is configured to move the inkjet head group back and forth relative to the recording medium to perform printing on both the forward and backward paths. In addition, the delay circuit set is shared during reciprocating motion, and the amount of delay is made variable independently for the forward and backward travels of the information applied to the print heads other than the heads located at both ends of the ink jet head group during the reciprocating motion. Features a reciprocating dot printing position control system.