JPH01294066A - Thermal transfer recorder - Google Patents

Abstract

PURPOSE:To perform a gradation recording with a high accuracy divided uniformly in density of printing, by presetting a pulse width to be applied to a heating element in the optimum m grades of lengths conforming with characteristics of a thermosensible paper or hot melt ink sheet. CONSTITUTION:When a digital timer 10 is reset, a latch circuit 5 gives the printing data in the first line from a buffer 7 to a driving circuit 4 to drive a heating element 1R selectively. Also, the printing data in the second line is latched from a storage part 8 to said buffer 7 with a delay of minute time by a delay circuit 12. At the same time, a pulse-width data storage part 9 outputs the pulse-width data in the second line to a comparator 11, keeps said state until the output of a timer 10 becomes the output 100 of said storage part 9, then prints the first line, and successively repeats said printing m times from the second line, third line...when said output becomes 80, 60.... Said printing pulse width is set so as to conform with characteristics of a thermosensible paper or hot melt ink sheet. Thus, it is possible to perform a gradation recording divided uniformly in density.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a thermal transfer recording device capable of highly accurate multi-tone recording.

BACKGROUND OF THE INVENTION In recent years, thermal transfer recording devices have become full-color and faster, and highly accurate multi-tone recording is required in order to obtain good half-tone recording images.

Generally, this type of thermal transfer recording apparatus has a configuration as shown in FIG.

That is, 1 is a thermal head section, 1 heating element 1R
are arranged in a line in a direction perpendicular to the plane of the figure.

14 is a heat-sensitive transfer ink sheet, which contains heat-melting ink 1;
3IL is applied onto the base film 13b. 1
4 is a recording paper, together with a thermal transfer ink sheet 13,
It is inserted between the thermal head section 1 and the platen 16. Note that the platen 16 is sufficiently pressed toward the thermal head so that the recording paper 14 and the thermal transfer ink sheet 13 and the thermal transfer ink sheet 13 and the heating element are brought into sufficient contact with each other.

Next, the heating element 1R of the thermal head section 1 is shown in FIG.
It has the configuration shown in .

That is, 1a is a heating element, and a pair of electrodes 1b are connected to both ends of the heating element. The heating element 1a has a wider width near the electrodes 1b, and a narrower width closer to the center between the electrodes 1b.

As a result, as shown in FIG. 5, the resistance value of the heating element 1& becomes smaller in the vicinity of the electrodes 1b, and becomes larger in the center between the electrodes 1b. therefore,
When a constant voltage is applied to the heating element 1R for a certain period of time, the higher the resistance value, the greater the amount of heat generated, so the density of the amount of heat generated at the center of the heating element 1R becomes higher. Utilizing this, by changing the voltage application time of the voltage applied to the heating element 1R, the heating element 1R has a calorific value according to the voltage application time.
The heat is generated concentrated at the center of the heating element 1R, and the recording area per dot can be freely changed depending on the amount of heat generated. In other words, multi-tone recording is possible. (Unexamined Japanese Patent Publication No. 60-58877).

With the above configuration, by sequentially applying a voltage to the heating elements 1R for a time corresponding to the printed data, a predetermined heating element 1R generates a heat amount corresponding to the voltage application time, and the heat generation The heat-melting ink 13 & is melted and transferred onto the recording paper 14 according to the amount, and predetermined printing is performed sequentially.

Here, gradation recording will be further explained with reference to the drawings.

FIG. 6 is a block diagram of a thermal head drive control circuit of a thermal transfer recording device using a conventional signal generation circuit.
Larger thermal head part 1. It is divided into three parts: a print data generation circuit section and a timing control circuit section.

The thermal head section 1 is composed of a plurality of heat generating elements 1R arranged in parallel, a drive circuit 4 having the same number of stages as the heat generating elements 1R, and a latch circuit 6 provided corresponding to the drive circuit 4. .

In this thermal head section 1, one electrode of the heating element 1R is commonly connected to the printing power source 6, and the other electrode is connected to the output terminal of the drive circuit 4. Further, the input terminal of the drive circuit 4 is connected to the output terminal of the latch circuit 6.

Next, in the print data generation circuit section 2, 8 is a print data storage section, which is a section for storing print data.

A buffer 7 takes out print data from the print data storage section 8 and outputs it to the thermal head section 1. 3a is a timing control circuit which outputs a data strobe signal (D-3TB) that controls the operation of the buffer 7 and a head strobe signal (H-8TB) that controls the operation of the latch circuit 6.
) is output.

The operation of the thermal head drive control section of the thermal transfer recording apparatus configured as described above will be described below with reference to FIG. 6.

Assuming that the number of heating elements is In and multi-gradation recording is performed by switching print data m times during the time to print one line (one line period), the print data storage section 8 has (width x Vertical) = (nX!l) Ma) IJ hook-shaped print data is stored. First, when the timing control circuit 3 & outputs the D-8TB signal to the buffer 7,
The buffer 7 outputs the first line data of the print data storage section to the latch circuit 6. Next is the timing control circuit 3! When L outputs the H-3TB signal to the latch circuit 6, the latch circuit 6
outputs the input signal from the buffer 7 to the drive circuit 4, and at the same time, the drive circuit 4 causes current to flow through the heating element 1R in accordance with the input from the latch circuit 6.

Here, it is assumed that when the print data in the print data storage section 8 is 1, the heating element 1R is energized.

Further, the timing control circuit 3a performs the second D-fST.
When the B signal is issued, the print data storage unit 80 goes through the same process.
The second row data is output from the buffer 7, and the heating element 1R is selectively energized according to the second row data at the time when the timing control circuit 3a issues the second H-8TB signal.

By repeating such a sequence from the first to the layer times, printing data is transferred once to one heating element 1R and energization according to the printing data is performed, and the printing operation for one line is completed. Here, timing control circuit 3& is D-8TB
In order to output the signal and the H-5TB signal at equal time intervals, the print data is switched at equal time intervals.

FIG. 7 is an explanatory diagram showing the relationship between print data in the print data storage section 8 and gradation recording, and the print data (FIG. 7 &)
and heating element application pulse (Fig. 7b).

Furthermore, the print dot size (Fig. 7C) and density (Fig. 7d)
) relationship is shown conceptually.

As explained above, by switching the print data supplied to the thermal head several times within one line printing time, it is possible to supply m applied pulse widths equally divided independently to multiple heating elements. This makes it possible to record multiple gradations.

Problems to be Solved by the Invention However, in the above configuration, since the time intervals for switching print data are equal, the width of the applied pulse applied to the heating element is divided evenly, and a high-precision multi-level When performing tone recording, that is, print recording in which the print density is equally divided, the resolution of the applied pulse width is insufficient.

That is, due to the characteristics of the heat-melting ink 13&, the relationship between the applied pulse width and the print density is non-linear as shown in FIG. In this case, the printing density is not evenly divided, and even when the number of gradation recording is reduced from one step (for example, 1 x layer step) and the optimum applied pulse width is selected, the printing density will not be equal to the printing density for two characters. An error occurs between the equally divided density (target value). (FIG. 8b) On the other hand, the error can be reduced by increasing the number of equally divided pulses and increasing the resolution, but the printing time becomes longer as the number of pulses increases.

SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to provide a thermal transfer recording device capable of recording high-precision gradations with evenly divided printing densities.

Means for Solving the Problems In order to solve the above-mentioned problems, the thermal transfer recording device of the present invention transfers data from the first time to the first time. The apparatus is equipped with a control circuit that can independently set the heating element driving time corresponding to one type of print data to any predetermined value.

Effect of the present invention With the above-described configuration, the pulse width applied to the heating element of the thermal heater is set in advance to the optimum length of one step according to the characteristics of the thermal paper or the heat-melting ink sheet. Highly accurate gradation recording with evenly divided print densities can be performed.

EXAMPLES The thermal transfer recording apparatus of the present invention will be described below with reference to the drawings. Note that the same heating element as in the conventional example is used, and a description of its structure and characteristics will be omitted.

FIG. 1 shows a block diagram of a thermal head drive control circuit in a thermal transfer recording apparatus of the present invention. It is divided into a print data generation circuit section 2 and a timing control circuit section 3. Of these, the thermal head section 1 and the print data generation circuit section 2 are the same as those of the conventional example, so a description of their construction will be omitted.

The timing control circuit section 3 is a circuit block that generates a data strobe signal D-8TB that controls the operation of the buffer 7 and a head strobe signal H-5TB that controls the operation of the latch circuit 5. Pulse width data storage unit 9 for storing intervals. Digital timer that counts up 10. A comparator 1 that compares the output of the pulse width data storage section 9 and the timer 10
1 and a delay circuit 12.

The operation of the thermal head drive control section configured as described above will be explained using FIG. 1.

Multi-gradation recording is performed by switching print data once at a preset arbitrary time interval during the time for printing one line (one line period). First, in the initial state, the print data is stored in the print data storage section 8, the pulse width data storage section 9 contains 0 in the first line, and the print data of the first stroke is stored in the print data storage section in the second line. The time required for the latch circuit 6 to hold the print data of the 1st line and the 1st line is also the time for holding the print data in the latch circuit 6.
It is stored as a constant up to the +1st line (corresponding to the mth line of print data). Also, the buffer 7 is a print data storage section 8.
The print data of the 01st line is output, and the latch circuit 5 does not output any output. That is, the heating element 1R is not driven.

Further, the pulse width data storage section 9 outputs the value o'f in the first row to the converter 11. In this state, the digital timer 10 (up counter starting from o)
When reset is applied to the comparator 11, the latch circuit 5
The latch circuit 6 outputs the H-3TB signal to the buffer 7.
The input (first row print data) is outputted to the drive circuit 4, and the drive circuit 4 selectively drives the heating element 1R according to the input print data. 1 from comparator 11
(The -8TB signal is slightly delayed by the delay circuit 12, and the D-5TB signal is output to the buffer 7. As a result, the next line of the print data storage section, that is, the print data of the second line, is latched in the buffer γ. The H-8TB signal from the comparator 11 is also output to the pulse width data storage section 9 at the same time, so that the pulse width storage section 9 stores the next row,
That is, the second row pulse width data (1003) is output to the comparator 11.

The digital timer 10 counts up from 0 after being reset, and this state is maintained until the output of the digital timer 10 becomes equal to the output (10o) of the pulse width data storage section. That is, the heating element 1R selectively generates heat according to the print data of the first line.

Next, when the output of the digital timer 10 becomes 100, the comparator 11 outputs the ll-5TB signal, and through the same sequence as the previous time, the heating element 1R is driven according to the print data of the second line and sent to the buffer 7. The print data of the third line is latched, the pulse width data storage section 9 outputs the pulse width data (8o) of the third line, and the digital timer 1
0 is reset again. and digital timer 10
This state is maintained until counting up from 75ZO and outputting 8o, that is, the heating element 1R selectively generates heat in accordance with the print data of the second line.

By repeating this cycle repeatedly, the heating element drive time corresponding to each type of print data transferred from the first data transfer to the first data transfer can be independently set to any predetermined value. It is possible.

FIG. 2 is a diagram showing the relationship between print data, pulse width data, and heating element application pulses. The pulse width, which was divided equally in the conventional method, can be divided into arbitrary widths.

You can see that it can be set to the length of the street.

FIGS. 3a and 3b show diagrams of the relationship between the applied pulse width and print density in this embodiment. In this way, in the thermal transfer recording device of the present invention, the head application pulse width can be optimally set according to the characteristics of the thermal paper or heat-melting ink sheet so that the print density is divided equally for each gradation. A thermal transfer recording apparatus set in this manner can perform gradation recording with evenly divided densities.

Effects of the Invention As described above, the present invention provides a thermal transfer recording device that performs multi-tone recording by switching the print data sent to the thermal head m times, in which the data is transferred from the first to the m-th data transfer. By installing a control circuit that can independently set the heating element drive time corresponding to each type of print data to any predetermined value, highly accurate gradation recording with even density division is possible. I can do it.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the main parts of a thermal transfer recording apparatus according to an embodiment of the present invention, FIG. 2 is a diagram explaining the principle of the embodiment, and FIG.
Figures a and b are characteristic diagrams showing the relationship between the applied pulse of the same example and the pulse width and print density of the same example. 1... Thermal head section, 1R... Heat generating element, 3... Timing control circuit section, 9...
...Pulse width data storage unit, 1o...Digital timer, 11-1°...Comparator, 12.
...Delay circuit. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure A 3 Figure IθD 2 (4030D 4170 Ink Calobalus (pse r) Figure 4! 5th ward - 11 hair X Figure 6

Claims (1)

[Claims] The thermal head has a plurality of heat generating elements arranged in parallel on the pressure contact surface, and data transfer of n print data corresponding to the n heat generating elements that perform printing simultaneously and driving of the corresponding heat generating elements is performed. By repeating this process m times, the energization time is varied for each heating element according to the print data.
It is configured to perform multi-gradation recording of n print dots simultaneously, and the heating element drive time corresponding to each type of print data transferred from the 1st to mth data transfer is independently set in advance. A thermal transfer recording device equipped with a control circuit that can be set to any predetermined value.