JPH02241760A - Printer control circuit - Google Patents

Abstract

PURPOSE:To minimize the thermal accumulation of a printing head and make print density uniform by controlling head energizing energy based on the second dot of data before the dot of print data for which the head is to be energized when dots of the same data are used. CONSTITUTION:Given data for which a printing head is energized, that is, the one two dots or one dot before data at the position of a dot, as D-2, D-1, CPU 1a temporarily holds the data in RAM 1b. Next given data located at a position for which the head is energized as D0, CPU energizes the head for the pulse width(a) part in accordance with the result obtained by performing the 'and' operation on data complement of data D-2 two dots before the dot for which the head is energized and data D-0 for which the head is to be energized now. In addition, the CPU switches the head ON for the pulse width (b) part in accordance with the results obtained by performing the 'and' operation on data complement of data D-1 one dot before the dot and data D-0 for which the head is switched ON. Finally the CPU switches the head ON for the pulse width (c) part in accordance with data D-0 for which the head is to be energized. Thus these four-step pulse widths can be controlled using the printing head, and therefore, the effect of thermal accumulation on the head can be minimized.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an interface circuit for a serial thermal printer.

(Summary of the Invention) In order to compensate for the deterioration in printing quality due to the thermal heat accumulation phenomenon, the serial thermal printer has a head energization energy control means based on the 11 history of 2-dot printing, and also has a serial thermal printer i-interface. circuit.

[Conventional technology]

In the interface circuit of a conventional serial thermal printer, the energization time of the next dot to be energized is increased or decreased depending on whether or not the same dot was energized immediately before. In line thermal printers, in dot block units (for example, 64 dots) of the head, the ratio of energized dots to non-energized dots in the block determines the i when the same program is driven next.
The opening time has been reduced.

[Invention tries to solve! I topic]

FIG. 4 shows an example of printing performed by the interface circuit of the serial thermal printer described above.

As shown in the drawing, there is a noticeable difference in print density between the printing start part and the printing end part. Also, when printing continuously, unnecessary color development (shown in Figure 5) due to residual heat of the head may occur.
#, L=: Deshima・5 problem 3).

Also, if you try to control the energization time of the dots by the ratio of the energized 1' dots and the non-energized dots of No. When there is a bias, the heat distribution of the head is biased, resulting in a problem that the uniform printing of 92 degrees is not maintained.

[Means for Solving the Problems] The present invention has been made to solve the above problems, and includes:
It is detected whether or not the two dots before the printing target 1) of ＼1' are energized, and the 4
A serial printer interface circuit was configured to control the energization time for each step.

[Effect]

During the specified head energization pulse of the thermal printer, 1' J Ll, 3 parts (0, 3
A method for controlling the energization energy will be described based on FIG. As shown in FIG.
'Head energization data from 1 min and 1 dot ago is 1'
, )-1, D-1, during the head energization pulse when both D-x and D-i are not energized, the 4th dot is 1. As shown in the energizing pulse +j+ column; i +
btoq? 'It becomes 100% energized. When 4 of I'll- is energized, during the 2nd energization pulse, the C b +
7095 is energized at c. When only D-1 is partially energized, the energizing pulse 111 is the 2nd door in Fig. 3),
ij 1 electric pulse of 1 + 60 a + c as shown here is 8
0% current is applied. I) When -z and D-+ are energized, the dot L in Fig. 13 is shown. As shown in the energization pulse 11 column, 50% energization occurs at C.

FIG. 3 shows the same principle during the energizing pulses of D-g and D-i (an example of the iJ!i energizing pulse determined based on this principle).

As mentioned in ``-1,'' during the energizing pulse, the energizing H history of the bed up to 2 dots t-tUN, which is the same as the energizing zero dot, is therefore the 4-stage terminal energizing pulse. Since control can be performed, the influence of high heat of the head can be reduced, variations in printing per printing can be reduced, and deterioration in printing quality can be prevented.

〔Example〕

Next, the present invention will be explained in detail C1 with reference to the drawings.

FIG. 1 is a functional block diagram showing an embodiment of the present invention.
1 is a single-chip microcomputer, 2 is a carriage motor drive circuit, 3 is a head drive circuit,
4 is a feed motor drive circuit, 5 is an oscillator for controlling the pulse width of a hemetite pulse width, and 6 is a printer mechanism. Single tesob micro combinator 1 is 1, CP
It is composed of an IJ section 1a, an 17AM section lb, and a ROM section 1c.

The setting during the head energization pulse is head energization pulse Ii.
This is done so that the oscillation period of the control oscillator 5 equals 20 power counts is included in the prescribed head energization pulse. Here the second
The count number of the a, b, and c portions of the pulse 11 shown in the figure is 6.
4.10 and is set in the ROMIC.

The data for head energization at 2 dots before the dot position where the 1ffi current should be applied and 1 minute i;
5D-i, the CPU 1a transfers this data to RA
It is temporarily held in M1b. Next V, when the data at the current position is 1111, the complement of the data D2 two dots ago, the data D to be energized now, and the data resulting from the AND operation are taken. The head of the center part is energized, and then the head of the middle part of the pulse as shown in Fig. 2 is Electrification is carried out, and finally, energization is performed in part C of the pulse in FIG. 2 according to data D to be energized now. The relationship between the printed dot data and the energizing pulse is as shown in FIG.

(Effect of the invention) Since the head energization energy control 4 is performed based on the print data up to two points before the print data that should be energized when turning 2 dots, the influence of heat accumulation at the throat is reduced. It is possible to make the print density uniform.

[Brief explanation of drawings]

FIG. 1 is a circuit block diagram showing one embodiment of the present invention, and FIG. 2 is an explanatory diagram showing the configuration of the - throat energization pulse [1].
Fig. 3 is an explanatory diagram showing print data and an example of the '4 electric pulse 111 control, and Figs.
- It is a printing example schematic diagram which shows the printing example by a control method. Applicant: Seiko! ? Industrial corporation? 1. Fill in the soil with the agent Takayuki Hayashi The circuit diagram of the frame diagram D... 7 Figure 1 Figure 5

Claims (1)

[Claims] In a printer interface consisting of a thermal printer control circuit, a thermal printer motor drive circuit, and a thermal head drive circuit, the thermal printer control circuit has four levels of head energy depending on the energization state of two dots before the same dot of the head. A printer control circuit comprising means for controlling energization time.