JPH05201052A - Thermal transfer recording method - Google Patents

Abstract

PURPOSE:To prevent the difference of dot diameters to be recorded from standing out for each recording block by a method wherein the recording of each line is performed by making thermal resistors, which are divided into a plurality of groups, heat alternately several times. CONSTITUTION:While carrying a recording paper and ink sheet, which are put together and inserted between contact surfaces of a thermal head and platen, blocks of thermal elements are made to heat alternately several times at the time of recording of each line. In the concrete form, respective heatings of blocks 11a-11d of the thermal elements are alternately repeated three times. Thus, by dividing the time which is required to heat the blocks 11a-11d of the thermal elements into three, the quantity to vary from a desired dot diameter in the recording of 1 line can be approximately evenly dispersed for each dot in the recording of the line. For this reason, even if a speed variation is generated when the recording paper passes the vicinity of the thermal head and platen, the difference of the dot diameters to be recorded does not stand out.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer recording method in which a thermal head having a plurality of heating elements arranged in parallel is driven separately.

[0002]

2. Description of the Related Art Generally, in a fusion type thermal recording device,
Gradation recording is realized by controlling the number of dots of a plurality of colors existing in a certain range on the recording paper and the degree of superimposition of the dots, and FIG. 2 is a schematic side view of the fusion type thermal recording apparatus. Show.

Reference numeral 1 is an ink sheet on which inks of a plurality of colors of yellow, magenta, cyan and black are applied in a longitudinal direction in a face-sequential manner in substantially the same size as a recording area, and 2 is an ink sheet 1 before recording. Ink sheet roll, 3 is a recording paper, 4 is a thermal head having a plurality of heating elements arranged in a line in the width direction of the recording paper 3, 5 is a platen arranged in contact with the heating elements of the thermal head 4, and 6 is A take-up roll that winds the ink sheet 1 after recording, 7 is a thermal head drive circuit that drives the thermal head 4, 8 is a control unit that controls the thermal head drive circuit 7, and 9 is a connection unit between a recording device and an operator. I / F (interface) part,
Reference numeral 10 is a recording data input terminal for inputting recording data.

FIG. 3 shows a drive circuit for driving the thermal head 4, 11 is divided into four blocks 11a to 11d, and a plurality of heating elements arranged in a line, 1
2 is an AND gate whose one input terminal is connected to the applied pulse input terminal 12a and whose output terminals are respectively connected to the heating elements 11, and 13 is synchronized with the clock signal input from the clock signal input terminal 13b, A shift register that holds the print data for each line serially input from the print data input terminal 10 corresponding to each heating element via the print data input terminal 13a, and 14 is connected to the shift register 13. The latch 14 is a latch that holds the print data based on the latch signal input from the latch signal input terminal 14 a. The latch 14 is connected to the other input terminal of the AND gate 12.

A case where recording is performed using a fusion type thermal recording device will be described below.

The curve in FIG. 4 shows the recording paper 3 passing near the thermal head 4 and the platen 5 when the recording paper 3 in FIG. 2 is conveyed at the same speed in the same direction (the direction of arrow A in FIG. 2). It represents the actual transport speed.

The horizontal axis in FIG. 4 represents time, the vertical axis of the curve in FIG. 4 represents distance, and the vertical axis of the pulse waveform in FIG. 4 represents voltage. Reference numerals 11a to 11d shown in the pulse waveforms of FIG. 4 denote blocks 11a of the heating element of FIG.
It corresponds to the heat generation of 11 to 11d, respectively.

In FIG. 3, the print data of the first line corresponds to each heating element serially via the print data input terminal 13a in synchronization with the clock signal input from the clock signal input terminal 13b. Shift register 1
Input is held in 3. The recording data held in the shift register 13 is transferred to the latch 14 based on the latch signal, and then input to the other input terminal of the AND gate 12. At this time, the print data of the second line has already been input to the shift register 13 from the print data input terminal 13a.

On the other hand, a recordable signal is input to one input terminal of the heating element 11 of the first block 11a via the applied pulse input terminal 12a, whereby the heating element 11 of the first block 11a shown in FIG. Heat is generated for a time corresponding to 11a, and as a result, the first block 1 in FIG.
Recording is performed for the width of 1a.

By repeating this operation in sequence for the second block 11b, ..., And the fourth block 11d, the recording of the first line is completed. Then, by repeating the above-mentioned operation for the second and subsequent lines, the recording for one screen is completed.

[0011]

Here, the conveying speed of the recording paper 3 is recorded on the recording paper 3 while passing near the thermal head 4 and the platen 5, that is, during the actual recording. It is desirable that the speed be constant in order to make the dot diameter uniform.

However, due to the influence of the inertia of the conveying device of the recording paper 3, the characteristics of the motor, and the like, the conveyance speed of the recording paper 3 causes unevenness in feeding as shown by the solid line (curve) in FIG. Not speed.

Therefore, even if the heating element is made to generate heat for the same time, if the recording is performed when the recording paper 3 is conveyed at a high speed, the dot diameter recorded on the recording paper 3 becomes long in the conveying direction of the recording paper 3. On the contrary, when the conveying speed of the recording paper 3 is slow, it becomes short.

As a result, when the dot diameters of the respective recording blocks recorded corresponding to the blocks 11a to 11d of the heating element 11 are compared, the dot diameters of the respective blocks differ, and the dot diameters of the respective recording blocks are different. Due to the difference in dot diameter, the boundaries of the recording blocks become very clear, and the recording quality deteriorates significantly.

The present invention has been made in view of the above problems, and the difference in the dot diameter to be printed is different for each recording block even if the conveying speed of the recording paper 3 is different, without adding any new structure. The purpose is to suppress the deterioration of recording quality so as to make it inconspicuous.

[0016]

SUMMARY OF THE INVENTION The present invention is directed to a thermal head having a plurality of heating elements arranged in parallel, a platen disposed in contact with the thermal head, and a recording paper conveying device for conveying recording paper. Means and an ink sheet conveying means for conveying an ink sheet, and the recording paper and the ink sheet are superposedly inserted between the thermal head and the platen while being conveyed, and the plurality of heating elements are conveyed. In a thermal transfer recording method in which line recording is performed by dividing a plurality of groups and applying a recording signal to each heating element of each group, recording of each line heats the heating elements of the above groups alternately a plurality of times. The feature is that it is done by urging.

[0017]

While the recording paper and the ink sheet are superposedly inserted between the thermal head and the platen and conveyed, the blocks of the heating elements are alternately heated a plurality of times during the recording of each line.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a view of the present invention showing the actual condition of the recording paper 3 passing near the thermal head 4 and the platen 5 when the recording paper 3 is conveyed at the same speed in the same direction (the direction of arrow A in FIG. 3 shows the correlation between the transport speed of No. 1 and the heat generation of the blocks 11a to 11d of the heating element. The horizontal axis in FIG. 1 represents time, and the vertical axis of the curve in FIG. 1 represents distance.
The vertical axis of the pulse waveform in the figure shows the voltage. In the case of the same configuration as the conventional one, the same reference numeral is given, and in the present invention, the four-division driving is performed similarly to the conventional one.

A feature of the present invention is that, with respect to the recording of one line, the heat generation of each of the blocks 11a to 11d of the heat generating element is alternately repeated three times.

The thermal transfer recording method of the present invention will be described below.

In FIG. 3, the recording data of the first line is synchronized with the clock signal serially input from the clock signal input terminal 13b, and the recording data input terminal 13 is provided.
shift register 1 corresponding to each heating element via a
Input is held in 3. The recording data held in the shift register 13 is transferred to the latch 14 based on the latch signal, and then input to the other input terminal of the AND gate 12. At this time, the same print data of the first line as that described above is input to the shift register 13 from the print data input terminal 13a again.

A recordable signal is input to one of the input terminals of the heating element 11 of the first block 11a via the applied pulse input terminal 12a, whereby the heating element 11 of the first block 11a of FIG. Heat is generated for a time corresponding to 11a, and as a result, the first block 1 in FIG.
Recording is performed for the width of 1a.

By repeating this operation alternately with the second block 11b, ..., And the fourth block 11d three times, the recording of the first line is completed. Then, by repeating the above-mentioned operation for the second and subsequent lines, the recording for one screen is completed.

As described above, according to the present invention, regarding the recording of one line, the time required for the blocks 11a to 11d of the heating element to generate heat is divided (in the case of the present embodiment, divided into three), Since the amount of variation from the desired dot diameter during line recording can be dispersed substantially evenly for each dot during line recording, the recording paper 3 passes near the thermal head 4 and the platen 5. At this time, even if the same speed fluctuation as in the conventional case occurs, the difference in dot diameter recorded in each block of the heating element becomes inconspicuous.

In this embodiment, the thermal head 4 is driven in four divisions and the time required for recording one line is divided into three, but the present invention is not limited to this. Also, a plurality of heating elements are divided into blocks for each adjacent heating element,
It is not limited to this.

[0026]

According to the present invention, the blocks of the respective heating elements as in the prior art are sequentially heated once to generate 1
The amount of fluctuation from the desired dot diameter due to fluctuations in the recording paper conveyance speed when line recording is performed is performed by alternately heating each block of the heating element a plurality of times.
As a result of being able to disperse the dots substantially evenly during the recording of the lines, the difference in the dot diameter recorded for each block of the heating element becomes inconspicuous, and deterioration of the recording quality can be suppressed.

[Brief description of drawings]

FIG. 1 is a correlation between an actual conveyance speed of a recording sheet passing near a thermal head and a platen in the present invention and heat generation of a block for each heating element.

FIG. 2 is a block diagram of a recording device

[Fig. 3] Thermal head drive circuit

FIG. 4 is a correlation between the actual transport speed of the recording paper passing near the thermal head and the platen in the related art and the heat generation of the block for each heating element.

[Explanation of symbols]

 3 recording paper 4 thermal head 5 platen 7 thermal head drive circuit 11 heating element

Claims (1)

[Claims] 1. A thermal head having a plurality of heating elements arranged in parallel, a platen arranged in contact with the thermal head, and a recording paper conveying means for conveying recording paper,
An ink sheet transporting means for transporting an ink sheet, and the plurality of heating elements are grouped into a plurality of groups while the recording sheet and the ink sheet are superposedly inserted between the thermal head and the platen and transported. In a thermal transfer recording method in which line recording is performed while applying a recording signal to each heating element of each group, recording of each line is performed by alternately heating the heating elements of the group a plurality of times. A thermal transfer recording method characterized by performing.