JPS61220871A - Serial-type printer - Google Patents

Abstract

PURPOSE:To enhance printing quality in both lateral-writing printing and vertical-writing printing, by a method wherein printing is conducted with a predetermined printing pulse width and a predetermined printing voltage in the case of lateral-writing printing, while printing is conducted with a shorter printing pulse width and a lower printing voltage in the case of vertical-writing printing. CONSTITUTION:In the case of lateral-writing printing, a selecting signal 5 is at a Lo level, whereby a signal obtained by ANDing printing data 4 with a pulse signal 2 is outputted from a NAND circuit 22. As a result, a predetermined printing dot period Ta and a predetermined printing pulse width ta are set, and a heating element 1 is driven therewith. A transistor 8 is turned ON, and a predetermined printing voltage Va is supplied from a power source 6 to the element 1. In the case of vertical-writing printing, a selecting signal 5 is at a Hi level, whereby a signal obtained by ANDing the printing data 4 with a pulse signal 3 is outputted from the NAND circuit 22. As a result, a printing pulse width tb shorter than the pulse width ta is set, and the element 1 is driven therewith. A transistor 9 is turned ON, and a printing voltage Vb lower than the voltage Va is supplied from a power source 7 to the element 1.

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 plurality of heating elements of the thermal head.
4 is a pulse signal whose period is the predetermined printing dot period Ta and whose pulse width is the predetermined printing pulse width ta, and 4 is a pulse signal whose period is the predetermined printing dot period Ta and whose pulse width is the predetermined printing pulse width ta.
The print data is longer than . 24 is the pulse signal 2
and the print data 4, and 23 is a transistor for switching the heating element 1. FIG. 6 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 printing device is 0.6 ms+ec −w 1 ,
In the case of Om Gen, when kanji, etc. are printed horizontally, the dots of the kanji are arranged in the horizontal direction, so the dots that should generate heat do not crowd in the vertical direction, and there is no significant heat storage phenomenon 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 printed vertically, the dot structure of the kanji character consists of many rows of dots that continuously generate heat in the vertical direction, which causes a heat accumulation phenomenon in the heating element, resulting in printing as shown in Figure 6bTlc. There is a problem in 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. The present invention solves these problems and is a serial type printing device equipped with a thermal head having a plurality of heating elements. Means for solving the zero problem that aims to put a printing device into practical use In order to solve this problem, the present invention provides a means for solving the problem of zero when printing horizontally, with a predetermined print dot period Ta, and a predetermined print dot period Ta. The heating element is driven with a pulse width ta and a predetermined printing voltage Va. Also,
The printing dot period during vertical writing printing is the same predetermined printing dot period Ta as that for horizontal writing printing, but the printing pulse width is shorter than the printing pulse width ta during horizontal writing printing (ta>tb). In addition, the heating element is driven at a printing voltage Wb(Va)Wb) lower than the predetermined printing voltage Va for horizontal writing printing.

Effect The present invention has the above-described configuration, and is capable of synchronizing predetermined printing dots Ta (Ta = 0.6m type ~
1. omsec), but in the case of horizontal printing, printing is performed with a predetermined printing pulse width ta and a predetermined printing voltage Va,
In the case of vertical printing, the printing pulse width tb (ta) tb) is shorter than the printing pulse width ta, and the printing voltage Va
Printing is performed at a lower printing voltage Vb(Va)Wb).

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 T a (
Ta = 0.6mgr: ~1.0m5ec), a pulse signal with a predetermined printing pulse width ta, 3 is the predetermined printing dot period Ta, and the pulse width is the predetermined printing pulse width ta.
4 is the predetermined print dot period Ta, and print data whose pulse width is longer than the predetermined print pulse width ta; 6;
6 is a power supply for horizontal writing printing, which supplies a predetermined printing voltage Va to the heating element 1; o7 is a power supply for vertical writing; The heating element 1 is supplied with a printing voltage Wb(Va)Wb) lower than the predetermined printing voltage V&. 8-10 is a transistor, 11.12 is a diode,
13 to 1e are resistors, 17 is an open collector inverter, 18 is an open collector buffer, and 19 to 22 are NAND circuits.

When printing with these configurations, in the case of horizontal printing, the select signal 5 is outputted as Loft, which causes the NA
The ND circuit 22 outputs the logical product of the print data 4 and the pulse signal 2. That is, the period is the predetermined printing dot period Ta (Ta = 0.6 m5eC-1
, 0m5eC), the printing pulse width becomes the predetermined printing pulse width ta, and the heating element 1 is heated to 7 + -.
→ Number?・ θ）μ Affairs No. K ・Han
1 l negative inN state, and a predetermined printing voltage Va is supplied from the power source 6 to the heating element 1 . In the case of vertical printing, since Ht is output from the select signal 6, the NAND circuit 22 outputs the logical product of the print data 4 and the pulse signal 3. That is, the heating element 1 is driven with a pulse width having a printing pulse width t b (t a ) tb) shorter than the predetermined printing pulse width ta. At the same time, the transistor 9 is turned on, and a printing voltage Vb (Va)Vb) lower than the predetermined printing voltage Va is supplied from the power supply 7 to 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, where a shows horizontal printing and b shows vertical printing.

Figure 3 a and b are print samples printed by the drive circuit of the serial type printing device of the present invention, a is a print sample of horizontal writing, and b is a print sample of vertical writing. According to the present invention, the predetermined printing period T
JL (T a = 0.6m5eC~1.0m5eC
), and in the case of horizontal writing printing, printing is performed with a predetermined printing pulse width ta and a predetermined printing voltage Va, and in the case of vertical writing printing, printing is performed with a printing pulse width tb (ta) shorter than the predetermined printing pulse width ta. )tb) By performing printing at a printing voltage Vb(Va)Vb) lower than the predetermined printing voltage Va, a serial printing device with good printing quality for both horizontal and vertical printing can be put into practical use.

Furthermore, in the present invention, both the printing pulse width and the printing voltage are controlled, and in the case of controlling only the pulse width,
The printing speed will be significantly reduced, but since the present invention also controls the printing voltage, there will be no significant reduction in the printing speed, and if only the printing voltage is controlled, the life of the thermal head will be shortened. However, since the present invention also controls the pulse width, it is possible to obtain the effect of not causing a decrease in life.◇

[Brief explanation of the drawing]

FIG. 1 is a drive circuit diagram of a serial type printing device according to an embodiment of the present invention, FIGS. 2a and 2b are timing charts of the drive circuit of FIG. 1 for horizontal writing printing and vertical writing printing, and FIG.
Figures a and b are explanatory diagrams showing print samples printed by the present invention, Figure 4 is a drive circuit diagram of a conventional serial type printing device,
FIG. 6 is a timing chart of a conventional drive circuit, and FIGS. 6a and 6b are explanatory diagrams showing print samples printed by a conventional serial type printing device. 1... Heating element, 2, 3... Pulse signal, 4... Print data, 6... Select signal, 6, 7... ·power supply. Name of agent: Patent attorney Toshio Nakao and one other person Figure 2 (b, Select signal 5 Figure 3 (Q-) Cb) Figure 4 Figure 5 Printed tape 4

Claims (1)

[Claims] It is equipped with a thermal head having a plurality of heating elements, and the printing dot period is set to a predetermined printing dot period Ta, and when horizontally printing characters etc., the predetermined printing pulse width ta is set.
, when printing with a predetermined printing voltage Va, and when vertically printing characters, etc., a printing pulse width tb (ta>tb) shorter than the predetermined printing pulse width ta, and the predetermined printing voltage V
A serial type printing device characterized by printing with a printing voltage Vb (Va>Vb) shorter than a.