JPS59230768A - Color printer - Google Patents

Abstract

PURPOSE:To provide the titled printer capable of preventing a horizontal color shift in color printing by adjusting the start position for horizontal printing with a heating head through the detection of a mark formed in a recording medium at the time of initial recording when the second and following printing operations take place. CONSTITUTION:At the time of initial recording, a mark ''M'' is printed outside a recording area PE. Then said mark ''M'' is detected by photosensors PS1, PS2 during the second and following recordings. The width ''W'' of the mark ''M'' is twice the detecting ranges W1, W2 of said sensor. When the mark ''M'' passes as if it were to overlap the sensors PS1, PS2, the outputs of these sensors are at low level simultaneously. For instance, when the mark ''M'' is too close to the sensor PS1, the output of the sensor PS2 is higher than that of the sensor PS1. Thus the deviated position of a form is detected, shifting the start position for printing with a heating head.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical field of the invention The present invention relates to color printing by overlay printing.
The present invention relates to a color printer that can eliminate color shift in the horizontal direction.

(2) Prior art and problems In general, in a color thermal transfer printer, as shown in FIG.
m is sent at the same speed in the direction of the arrow by the feed rollers R1 and R2, and recording is performed by the heat generating head H. - When recording of - times (single color) is completed, the heat generating head H is moved in the direction of arrow B, and only the paper FA is brought to the initial position in the direction of the pick arrow A', and the winding is also ε by the amount fed in the direction of the arrow. vinegar.

When the paper FA returns, the heat generating head H is moved in the direction of arrow B', and the paper FA and color ink sheet S are newly loaded.
The next color portion of Fi is sandwiched between the thermal head H and the platen PR, and the next recording is performed.

The above process is repeated multiple times to perform color recording.

Note that pRo is a paper roll, and R1 and R2 are ink rollers.

By the way, in this method, it is necessary to prevent color shift in the vertical and horizontal directions.

In the device shown in Fig. 1, regarding the vertical deviation,
This can be prevented by controlling the feed it of the paper FA, but since there is no standard for the printing start position in the horizontal direction, it is difficult to prevent this.

(3) Object and structure of the invention The present invention has been made in view of the above points, and an object of the present invention is to provide a printer that can prevent color misregistration in the horizontal direction. While moving an ink sheet impregnated with thermal transfer ink and a recording medium in a superimposed state, a heating head heats the ink sheet and records on the recording medium, and then only the recording medium is moved in the opposite direction. In a color printer that performs color printing by moving the mark to the same area and recording again in the same area multiple times, a mark is formed outside the recording area of the recording medium during the first recording, and during the second and subsequent recordings, This is achieved by a color printer characterized in that the mark pair is detected by a photo sensor, and the print start position in the horizontal direction by the heating head is adjusted based on the output from the photo sensor.

(4) Examples of the invention The present invention will be explained below based on examples.

An overview of the present invention will be explained with reference to FIGS. 2 and 3.

In the present invention, as shown in FIG. 2, a black mark M is printed outside the recording area PE during the first recording.

Then, when printing is performed for the second time, this mark M is detected by the photosensors Psl and PS2. The width W of the mark M is the photosensor Psl.

The detection ranges Wl and W2 of PS2 are twice as large.

Therefore, is this mark M 7 men? If ps1° passes exactly overlapping with PS2, the output levels of the 7th sensor Psl and PS2 will decrease in the same way as shown in Figure 3 (a). For example, if the mark M is biased towards the 7th sensor PSI. As shown in Figure 3(b), there are 7 sensors PS2.
Since the reflected light from the paper FA is manually applied, the output becomes higher than the output of the photosensor PEII. This detects any misalignment of the paper and shifts the printing start position of the heating head.

FIG. 4 shows a concrete block diagram.

In the figure, AMI, AM2 is an amplifier, OOM is a comparator,
PsT is a shift register, vM is an image memory, AND is an AND gate, and BUF is a buffer with a latch function, and the same components as in FIGS. 1 and 2 are given number codes.

To explain the operation, the photosensor Psl.

The output of P82 is amplified by amplifiers AMI and AM2,
Comparator OOM outputs the level difference.

The preset circuit ps presets the preset counter 0ONI to a value corresponding to the level difference.

Preset counter 0ONI is clock counter 0O
Reset by frame clock FK from N3,
Count clock OK.

Then, for example, the most significant bit output of the preset counter 0011 is outputted to the AND with the clock OK. The most significant bit output is also input to the enable terminal E.

AND gate AND output pc is address counter 0ON
After this output pc is input, the address counter 0ON2 starts counting the clock CK, and inputs the address signal ADD to the image memory VM.

Image data read out from the image memory lJvM by the address signal is input to the shift register SFT in synchronization with the clock OK.

Then, the buffer BU is synchronized with the frame clock FK.
The power is transferred to F', and the heating head H is applied.

Here, if the position of the mark M is shifted, the preset value changes, and this causes the time from being reset by the frame and clock PK to the rise of the output PC to be as shown by PO'l and PO2 in Figure 5. are different.

Therefore, the timing at which the address signal is input from the address counter 0ON2 also differs as shown by ADDI and ADD2.

On the other hand, when there is no image data from the image memory VM, the shift register performs a first-order shift of logic 60'', and when image data is output from the image memory VM, it sets this image data.

Therefore, the position of the image data in the shift register SFT shifts to the left or right depending on the rise time of the output PC.

This situation is shown in Case 1 and Case 2. Case 1 shows when the image data read out by the address signal ADDI is hit, and case 2 shows the case when the image data read out by the address signal ADD2 is set.

Since the image data in the shift register SFT is directly applied to the heating head via the buffer 1BUF, the printing position shifts to the left and right.

(5) Effects of the invention As described above, according to the invention, since the printing position in the horizontal direction can be controlled, it is possible to prevent color misregistration.

[Brief explanation of the drawing]

Figure 1 is a diagram showing an overview of the Kashi printer, Figure 2, Figure 3.
4 is a diagram showing the principle of the present invention, FIG. 4 is a diagram showing an embodiment of the present invention, and FIG. 5 is a diagram showing a time chart thereof. In the figure, AMI, AM2 is an amplifier, OOM is a comparator,
ps is a preset circuit, 0ONI is a preset counter, 0ON2 is an address counter, 0ON3 is a clock counter, OSa is an oscillator, SFT is a shift register, V
M is an image memory, AND is an AND gate, and BUF is a buffer with a latch function.

Claims (1)

[Claims] In a color printer that prints on the same area of a recording medium by overlapping printing using multiple color areas of an ink sheet, a mark is formed outside the recording area of the recording medium during the first recording, and a mark is formed on the second printing. During subsequent recording, the mark is detected by a pair of seven photosensors, and the print start position in the horizontal direction by the heat generating head is determined based on the output from the photosensor. color printer.