JPS61219668A - Serial-type printer - Google Patents

Abstract

PURPOSE:To obtain a favorable printing quality in both lateral-writing printing and vertical-writing printing, by a method wherein lateral-writing printing of characters or the like is conducted with a predetermined printing pulse width ta, while vertical-writing printing is conducted with a printing pulse width tb shorter than the pulse width ta. CONSTITUTION:In the case of lateral-writing printing, a selection signal 5 at a Lo level is outputted, and a signal obtained by ANDing printing data 4 with a pulse signal 2, that is, a signal with a predetermined print dot period Ta and a predetermined printing pulse width ta is outputted from a NAND circuit 9 to drive a heating element 1. In the case of vertical-writing printing, a selection signal 5 at a Hi level is outputted, and a signal obtained by ANDing the printing data 4 with a pulse signal 3, that is, a signal with a printing pulse width tb shorter than the pulse width ta is outputted from the NAND circuit 9 to drive the heating element 1. Accordingly, a serial-type printer showing a favorable printing quality in both lateral-writing printing and vertical-writing printing can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a serial printing device equipped with a thermal head having a plurality of heating elements.

BACKGROUND OF THE INVENTION Conventionally, this type of serial type printing device has been operated by a drive circuit shown in FIG. In FIG. 4, 1 is one of the plural heating elements of the thermal head, 2
4 is a pulse signal whose printing dot period is a predetermined printing dot period Ta and whose pulse width is a predetermined printing pulse width ta, and 4 is print data whose period is the predetermined printing dot period Ta and whose pulse width is longer than the printing pulse width ta. be. 24 is an AND which takes the logical product of the pulse signal 2 and the print data 4.
A circuit 23 is a transistor for switching the heating element 1. FIG. 5 shows a timing chart of this drive circuit.

Problems to be Solved by the Invention In such a circuit, the predetermined printing dot period Ta of the serial type printing device is o, am S[lC-1,0m
In the case of 5eC, when Chinese characters, etc. are printed horizontally, the dots of the Chinese characters are arranged in the horizontal direction, so the dots that should generate heat do not crowd in the vertical direction, and the heat storage phenomenon does not occur in the heating element. Therefore, the printing quality shown in FIG. 6(-) can be obtained, and the technology has reached the point where it can be put into practical use. However, when printing in vertical writing, the dot structure of the kanji character is made up of rows of dots that generate heat continuously in the vertical direction and are also tilted, so a heat accumulation phenomenon occurs in the heating element, resulting in printing as shown in Figure 6). The problem is that a serial type printing device that has good printing quality for both horizontal and vertical printing, which is required for a printing device, has not been put into practical use. there were.

The present invention solves these problems by providing a serial printing device equipped with a thermal head having a plurality of heating elements, which has good print quality for both horizontal and vertical printing. The purpose is to put it into practical use.

Means for Solving the Problem In order to solve this problem, the present invention performs printing at a predetermined print dot period Ta and a predetermined print pulse width ta during horizontal printing. In addition, the printing dot period for vertical printing is the same as the predetermined printing dot period T as for horizontal printing.
a, but the printing pulse width is a printing pulse width tb (ta
) tb ) to print.

Function The present invention has the above-described configuration, and the present serial type printing device has a predetermined printing dot period Ta (Ta = O, θm5ec
~1.0m5ec), but in the case of J horizontal printing, printing is performed with a predetermined printing pulse width ta, and in the case of vertical printing, the printing pulse width th (ta) is shorter than the printing pulse width ta. tb) to print.

Embodiment FIG. 1 shows a drive circuit for a serial type printing device according to the present invention. 1 is a heating element, 2 is a predetermined printing dot period Ta (T
a=o, emsec-1,0m5ec), a pulse signal with a predetermined print pulse width ta, 3 is a predetermined print dot period Ta, and a print pulse width tb (ta) tb) whose pulse width is shorter than the print pulse width ta. A certain pulse signal 4 has a period Ta and a pulse width the printing pulse width ta.
5 is a select signal for selecting horizontal or vertical printing, 6 to 9 are NAND circuits, 1
0 is a transistor.

With these configurations, in the case of horizontal printing, the select signal 6 outputs Lo, and the NAND circuit 9 outputs a signal obtained by logically multiplying the print data 4 and the pulse signal 2, that is, the period is a predetermined print dot period Ta. (Ta =
0.6 m5ec to 1.0 m5eC), the pulse width becomes the predetermined printing pulse width ta, and the heating element 1 is driven. In addition, in the case of vertical printing, the select signal 6
, and the NAND circuit 9 outputs a signal obtained by ANDing the print data 4 and the pulse signal 3, that is, a print pulse width tb (ta) tb whose pulse width is shorter than the predetermined print pulse width ta. ) to drive the heating element 1.

FIGS. 2a and 2b are timing charts of the drive circuit of the serial type printing device of the present invention, in which (a) is horizontal printing;
) is vertical printing.

3a and 3b are print samples printed by the drive circuit of the serial type printing device of the present invention, (a) is a horizontal writing print sample;
(b) is a print sample of vertical printing.

Effects of the Invention As described above, according to the present invention, the predetermined printing dot period Ta
(Ta = 0.6m5eC-1,0m5ec) is kept constant, and in the case of horizontal writing printing, printing is performed with a predetermined printing pulse width t&, and in the case of vertical writing printing, printing is performed shorter than the predetermined printing pulse width ta. Pulse width tb (ta
)tb), it is possible to put into practical use a serial type printing device with good print quality for both horizontal and vertical printing.

Furthermore, according to the present invention, since the printing pulse width is changed, it is very easy to control and can be configured with a simple circuit.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a drive circuit diagram of a serial printing device according to an embodiment of the present invention, and FIGS. 2a and 2b are timing charts of the drive circuit of FIG. 1 during horizontal writing and vertical writing. , FIGS. 3a and 3b are explanatory diagrams showing print samples printed by the present invention, FIG. 4 is a drive circuit diagram of a conventional serial type printing device, FIG. 5 is a timing chart of a conventional drive circuit, and FIG. The figure is an explanatory diagram showing a print sample printed by a conventional serial type printing device. 1... Heating element, 2, 3... Pulse signal, 4... Print data, 5... Select signal. In the castle school La R power Figure 3 (a-n 47 & l -N heating element t bulbs signal, 2 print te-, da 4 left every number 5 heating element l pulseless number 3 print data 4 select signal 5 (OL) No. Figure 4 Figure 5 completed Tape 4 Figure 6 (C

Claims (1)

[Claims] It is equipped with a thermal head having multiple heating elements, has a predetermined printing dot period of Ta, and when printing characters etc. horizontally, it prints with a predetermined printing pulse width ta, and when printing characters etc. vertically, it prints with a predetermined printing pulse width ta. The predetermined printing pulse width t
A serial type printing device characterized by printing with a printing pulse width tb (ta>tb) shorter than a.