JPH01301339A - Medium contrast thermal recording system - Google Patents

Abstract

PURPOSE:To easily control an applied pulse width in matching relation to a printing condition or the density characteristic of thermal paper and to obtain highly accurate medium contrast thermal recording, by constituting the title system so that applied pulses having two or more kinds of widths are made settable and each applied pulse width is not affected by drive frequency. CONSTITUTION:Printing data are transferred by shift registers 8 from data 1 to n simultaneously with regard to respective bits. Next, the respective bits of all data are temporarily stored simultaneously by latches 7 and the latched data are successively outputted to drivers at every dots by multiplexers 6 and, in synchronous relation to the output of said data, applied pulses having the widths corresponding to the respective bit data are successively applied. By this method, the total applied pulse width is changed by the combination of two or more applied pulses free in a set width to perform printing. A medium contrast can be obtained by controlling the total pulse width.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a halftone thermal recording system that produces multiple gradations depending on print density, for example, in thermal recording for printers or thermal transfer recording.

[Conventional technology]

Figure 3 is a circuit diagram schematically showing a conventional halftone thermal recording system. In the figure, (1) is an n-bit down counter and an n-bit shift register for simultaneously transferring n-bit data. , (2) a zero detector that determines whether the content of the n-bit down counter (1) is q″01, and (3) an n-bit down counter of the clock signal that receives the signal from the zero detector (2). (1) is a clock control circuit that sets the voltage to be applied; (4) is a buffer amplifier for driving the heating element.

Next, the operation will be explained. In FIG. 3, n-bit binary data is transferred bit by bit in parallel by an n-bit down counter (1) in shift register mode. When the transfer is completed, the n-bit down counter (1)
is switched to the down counter mode, and the binary data is counted down until "0" is detected by the zero detector (2). Meanwhile, the zero detector (2) continues to keep the buffer amplifier (4) in a driven state. Clock control circuit (
3) applies a clock signal to the n-bit down counter (1) until the zero detector (2) detects 101. When the zero count ends, the zero detector (2) sends the end signal to the clock control circuit (3). and buffer amplifier (4)
Stops driving. Upon receiving the end signal, the clock control circuit (3) stops applying the clock to the n-bit down counter (1).

As shown in Fig. 4, n bits of applied pulse data are counted in synchronization with the drive frequency using the method described above, and 1
This method used the clock cycle as the minimum pulse width to obtain gradations.

[The problem that the invention attempts to solve]

In the conventional halftone thermal recording method, the applied pulse width is limited by the driving frequency of the clock control circuit as described above, so if there is a change in temperature or the sensitivity of the thermal paper, the printing pulse width can be changed by changing the driving frequency. There were problems in that the width had to be changed, and the applied pulse width could only be changed linearly depending on the print data.

This invention was made to solve the above problems, and it is possible to change the printing pulse width regardless of the driving frequency, and the applied pulse width does not change linearly depending on the printing data, but has a certain degree of freedom. The purpose is to obtain a halftone heat-sensitive recording method that can change.

[Means to solve the problem]

The halftone thermal recording method according to the present invention places a shift register and a latch for each bit of print data of each print dot, and sequentially applies an application pulse having a width corresponding to the bit data to each bit. Multiple gradations can be obtained by combining applied pulses with different widths.0 [Operation] Setting applied pulses with a plurality of widths in this invention is not limited to the driving frequency, and can be applied to each gradation. An applied pulse width can be obtained, and the applied pulse width can be changed not linearly but with a certain degree of freedom depending on the print data. [Example] Hereinafter, an example of this invention will be described with reference to the drawings. explain. 1st
In the figure, (5) is a heating resistor in the printing part, (6) is a multiplexer that selects which bit of data to print, (7) is a latch that temporarily stores each bit of print data, (8) is a shift register that transfers each bit of print data.

In FIG. 1, each bit of print data from data 1 to data n is simultaneously transferred by a shift register (8). Next, each bit of all data is temporarily stored simultaneously by a latch (7). The latched data is sequentially output to the driver bit by bit by the multiplexer (6), and in synchronization with this, an application pulse having a width corresponding to each pit data is sequentially applied.

FIG. 2 is a waveform diagram showing the timing and output of applied pulses, and although the output pulses are separated compared to the conventional case shown in FIG. 4, the total pulse time is the same.

In this way, printing is performed by changing the total applied pulse width by combining a plurality of applied pulses with freely set widths.

In the above embodiments, the case of thermal recording or thermal transfer recording has been described, but it goes without saying that the present invention can also be applied to other recording methods in which halftones can be obtained by controlling the total pulse width.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to set applied pulses with multiple widths, and the applied pulse width is not affected by the driving frequency, so it can be easily adjusted according to printing conditions, density characteristics of thermal paper, etc. It is possible to adjust the applied pulse width and has the effect of obtaining highly accurate halftone thermal recording.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing a half-tone thermal recording method according to an embodiment of the present invention, FIG. 2 is a pulse waveform diagram of each part of FIG. 1, and FIG. 3 is a circuit diagram showing a conventional half-tone thermal recording method. FIG. 4 is a pulse waveform diagram of each part of FIG. 3. In the figure, (5) is a heating resistor, (6) is a multiplexer, (7) is a latch, and (8) is a shift register.

Claims (1)

[Claims] (1) In a thermal recording method in which thermal paper is colored by heat, the print data for each print dot is expressed as several bits of data, and the print data is simultaneously serially input for each bit using the same number of shift registers and latches as the data. , by latching and sequentially applying a pulse with a width corresponding to the bit data to each bit, and applying pulses to each print dot the same number of times as the number of bits of the print data. A halftone thermal recording method characterized by performing halftone recording by a combination of applied pulses.