KR0158105B1 - Strobe pulse starting point variable circuit for tph - Google Patents

Abstract

It is a technique to vary the starting point of strobe pulses and to improve the unevenness of optical density between printing blocks and lines generated by printing at a time when the dynamic characteristics of the receiving stepping motor are not constant when data is recorded from the facsimile to the thermosensitive recording element. .

In order to improve the strobe pulse generation technique of the strobe pulse generation method by the conventional print start pulse, the first count data which is variable data for the starting point for each strobe, and the first count data are obtained by counting the first count data by the print start pulse. By generating a strobe pulse with the strobe start signal as the strobe pulse start point, the dynamic characteristics of the receiving stepping motor are printed at a time point.

Description

Strobe pulse start point variable circuit of thermal recording element

1 is a conventional circuit diagram.

2 is an operation timing diagram of each part of FIG.

3 is a circuit diagram according to the present invention.

4 is an operation timing diagram of each part of FIG.

* Explanation of symbols for main parts of the drawings

10: buffer 20: first counter

30: second counter 40: shift register

50: strobe detection unit

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a strobe pulse starting point variable circuit of a thermosensitive recording element in a facsimile system. It relates to a circuit that is variable to improve the uniformity of optical density.

In general, a facsimile uses a thermal print head (TPH) to record data on a thermal recording paper. When data is written by the thermal recording element, data is usually divided into four blocks or eight blocks for printing. Each block is driven by four or eight strobe pulses, which are external drive pulses. The conventional circuit for generating the strobe pulse is shown in FIG. 1, in which count data corresponding to the strobe pulse width time of the thermal recording element is first input to the counter 1 in the copy or receive mode. When a print start pulse Ps as shown in FIG. 2A is input to the counter 1 at the time of printing, the counter 1 sends the counter data value to the clock CLK. Count in synchronization. The output signal of the counter 1 is input to a shift register 2 so that strobe pulses S1-S4 having the same pulse width are continuously generated as shown in FIG. 2 (C)-(F). And is applied to a thermal recording element (not shown). Accordingly, the thermal recording element prints data according to the strobe pulses as shown in FIGS. 2C and 2F.

At this time, the count data value counted by the counter 1 becomes the pulse width T of the strobe pulses S1-S4 as shown in FIGS. The operation timings of the circuits of FIG. 1 and FIG. 2 are examples of the case where data is printed by dividing the data into four blocks, and the strobe pulses are eight when the data is divided into eight blocks.

In this manner, once the count data is input, a strobe pulse having four or eight identical pulse widths is simply generated while being shifted in time.

On the other hand, in general, a motor driving pulse Mp such as FIG. 2 (B) for driving each phase of the receiving stepping motor is applied at the same time interval in one line printing period so that 1 / during one line printing. The thermal recording paper will be ejected by 7.7mm.

Therefore, as shown in FIG. 2, no time synchronization is performed between the motor driving pulse Mp and the strobe pulses S1-S4 of each block.

Therefore, in the conventional circuit as described above, since the synchronization between the motor drive pulse and the strobe pulse is not synchronized, each block to be printed is printed at a time point at which dynamic characteristics of the receiving stepping motor are not constant, so that the uniformity of optical density between each block to be printed is obtained. There was a problem that can not be achieved.

In addition, printing is finished at the point of 3/4 of 1 / 7.7mm, which is the movement distance of one line. In the last 4th motor drive step, only the recording is discharged by the motor, so there is a difference in light density for each line. .

Accordingly, an object of the present invention is to provide a strobe pulse starting point variable circuit capable of achieving uniform optical density by varying a strobe pulse start point of a thermosensitive recording element so as to be synchronized with a drive pulse of a receiving stepping motor in a facsimile.

Hereinafter, with reference to the accompanying drawings of the present invention will be described in detail.

3 is a circuit diagram according to the present invention, a buffer 10 for sequentially inputting first counter data, which is data for starting points for each strobe, by a strobe detection signal, and

A first counter 20 generating a strobe start signal by counting a first count data value output from the buffer 10 in synchronization with the first clock CLK1 by a print start pulse;

A second counter 30 that inputs second count data corresponding to the strobe pulse width time and generates the strobe pulse width signal by counting the second count data value in synchronization with the second clock CLK2 according to the strobe start signal. )Wow,

A shift register 40 for shifting the output strobe pulse width signal of the second counter 30 and outputting a strobe pulse;

The buffer 10 detects an end point of each strobe pulse output from the shift register 40 and loads a strobe detection signal for loading first count data of the buffer 10 into the first counter 20. It is composed of a strobe detection unit 50 provided to.

4 is an operation timing diagram of each part of the third diagram.

An operation example of FIG. 3 according to the present invention will now be described in detail with reference to the operation timing diagram of FIG.

The first count data for the start point of the driving strobe pulse of the thermal recording element and the second count data corresponding to the strobe pulse width time are not shown in the copy or receive mode. If each is input to 30,

The first counter 20 receives the first count data for the first strobe start point from the buffer 10 and counts in synchronization with the first clock CLK2 by the print start pulse as shown in FIG. Start to generate strobe start signal.

At this time, the first counter 20 counts the starting point of the driving strobe pulse of the thermal recording element.

The strobe start signal is input to the second counter 30. Accordingly, the second counter 30 starts counting the second count data value in synchronization with the second clock CLK2 to generate a strobe pulse width. Generate a signal. The output signal of the second counter 30 is input to the shift register 40. Therefore, the first strobe pulse S1 as shown in FIG. 4C is generated in the shift register 40. The start point of the first strobe pulse S1 is determined according to the strobe start signal of the first counter 20, and the pulse width T is determined according to the strobe pulse width signal of the second counter 30.

Meanwhile, when the first strobe according to the first strobe pulse S1 ends, the strobe detector 50 detects an end point of the first strobe pulse S1 and outputs a strobe detection signal to the buffer 10.

The buffer 10 then loads the first count data for the next second strobe start point into the first counter 20. Accordingly, the second strobe pulse S2 as shown in FIG. 4D is output to the shift register 40 by the same operation as that of the first strobe.

As described above, the shift register 40 sequentially generates and outputs strobe pulses according to the number of blocks. Herein, if the thermal recording element is divided into four blocks and printed, the shift register 40 has one period of a print start pulse as shown in FIG. Four strobe pulses S1-S4 are outputted as follows. Accordingly, the thermal recording element prints data according to the strobe pulses S1-S4.

Therefore, after the print start pulse Ps as shown in FIG. 4A is generated and the motor is driven by the motor drive pulse Mp as shown in FIG. 4B, the dynamic characteristics of the motor are constant. After the predetermined time t1-t4 from the motor driving pulse Mp, the strobe pulses S1-S4 are generated as shown in FIG. 4 (C)-(F) so that printing can be performed at a uniform time.

On the other hand, the predetermined time (t1-t4) by the strobe start signal can be changed by changing the first cart data, and may be appropriately changed according to the driving characteristics of the receiving stepping motor.

In addition, since the first counter 20 counts the print start pulse Ps as shown in FIG. 4A, the second strobe may be shorter than the pulse width T of the first strobe pulse S1. When the first count data for the starting point is input, the first count data is continuously output to the second strobe.

As described above, the present invention is a circuit for generating drive strobe pulses of a thermosensitive recording element at a uniform time interval in a region where dynamic characteristics are stable in accordance with a drive step of a receiving stepping motor in a facsimile. There is an advantage to improve the quality of the fax by overcoming.

Claims (2)

In a strobe starting point variable circuit of a thermosensitive recording element in a facsimile system, a buffer 10 for inputting first counter data, which is data for a starting point for each strobe, and sequentially outputting the strobe detection signal and a print start pulse are provided. A first counter 20 that counts the first count data value output from the buffer 10 in synchronization with the first clock CLK1 and generates a strobe start signal, and second count data corresponding to the strobe pulse width time. And a second counter 30 for generating a strobe pulse width signal by counting the second count data value in synchronization with the second clock CLK2 according to the strobe start signal, and the second counter 30. A shift register 40 for shifting an output strobe pulse width signal to output a strobe pulse, and each strobe pulse output from the shift register 40; And a strobe detection unit (50) for providing a strobe detection signal to the buffer (10) to detect an end point of the buffer (10) and to load the first count data of the buffer (10) to the first counter (20). Strobe starting point variable circuit of thermal recording element. 2. The strobe pulse start point variable circuit of claim 1, wherein the start point of each strobe pulse can be varied by changing the first count data.