JPS6213160A - Printing system for serial thermal printer - Google Patents

Abstract

PURPOSE:To improve the print quality by increasing the print energy of the 1st dot or the 1st and the least significant dot in graphics print more than the print energy to other dots. CONSTITUTION:When the microprocessor discriminates the mode to be the graphics mode, the data drive of the 1st dot - 8th dot or the 1st-24th dot is turned on to set a TIMER 1. When the time of the TIMER 1 comes to T1, the data drive for the 2nd dot - 7th dot or the 2nd dot - 23rd dot is turned off, a TIMER 2 is set, and when the time of the TIMER 2 comes to T2, that is, the time T1+T2 elapses, the data drive for the 1st and 8th dot or the 1st dot 24th dot is turned off. Thus, the drive time of the 1st dot and the 8th dot or the 1st dot and the 24th dot is extended to increase the print energy more than that for the other dots, thereby uniforming the dot print density or print size independently of the physical arrangement of the dots.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to printing energy control when performing graphics printing in a serial thermal printer, particularly in a serial thermal transfer printer.

[Conventional technology]

A conventional serial thermal transfer printer uses, for example, a thermal head 2 in which eight heating elements 1 are arranged in a vertical line as shown in FIG. 2, and is wound around a platen 3 as shown in FIG. Printing is performed on a printing medium 4 via a thermal transfer ribbon 5. When printing graphics such as copying a CRT screen using a serial thermal transfer printer, one line is usually printed using 8-24 raw points, and then 8
Alternatively, a changeover operation for 24 raw points is performed and graphics for one screen are printed.

゛ [Problem that the invention seeks to solve] However,
In this conventional example, when printing graphics,
Since the printing energy of all raw points is generally the same,
As shown in Figure 4, the 1st dot and the 8th dot are the raw points at both ends.
The thermal transfer energy of one dot is different from that of other dots due to the difference in heat dissipation effect due to the difference in physical arrangement. Therefore, the print density of the raw dots at both ends becomes thin, or the size of the raw dots becomes small as a result of printing. As a result, thin white lines appear between printed lines, resulting in a problem of poor print quality.

The present invention was devised to solve the above-mentioned problem, and its purpose is to improve the print quality by uniformizing the print density and the size of printing pixel dots.

[Means for solving problems]

In order to achieve the above object, the present invention provides a printing method for a serial thermal printer that prints on a print medium using a thermal head in which a plurality of heat generating elements are arranged in an array. The printing energy for the dots is larger than that for other dots.

[Effect]

In the present invention having the above-mentioned characteristics, when it is determined that the graphics mode is selected, for example, the cheek 1 live of all dots is turned on, and when the time TI has elapsed, the data drives of the first dot or the data drives other than the first dot and the lowest dot are turned off. Then, after a time T2 has elapsed, the data drives for all dots are turned off. Also, like this, the first
Instead of increasing the applied energy by increasing the energy application time to the dot or the first dot and the lowest dot, the applied voltage is made larger to the first dot or the first dot and the lowest dot than to other dots. or by increasing the heating area, cutting it, or adding a preheating element.
To make the printing density and printing size of dots uniform without being affected by the physical arrangement of the dots.

〔Example〕

Hereinafter, the first embodiment of the present invention will be explained as shown in FIG. 1 and FIG. 5(a).
, (Explain based on b'l.

FIG. 1 is a flowchart of head drive processing showing a first example of the present invention, and FIG. 5 is a time chart showing the drive time of each dot in the first example of the invention.
FIG. 5(a) shows the case of full printing with 8-dot graphics, and FIG. 2(b) shows the case of full printing with 24-dot graphics.

Head drive processing will be explained based on FIG. When the microprocessor (not shown) determines that it is the graphics mode, it turns on the data drives of the 1st to 8th dots or the 1st to 24th dots, and selects TJMEJ'? ].

When the TIMER1 becomes T], the data drives of the second to seventh dots or the second to 23rd dots are turned off, and TIMER2 is set, and the TIMER2 is set.
When MER2 reaches T2, that is, when the time TI+T2 has elapsed, the data drives '1 of the 1st and 8th dots or the 1st and 24th dots are turned off.

Therefore, by the above-described operation, the driving time of the first dot and the eighth dot or the first dot and the twenty-fourth dot is lengthened, and the energy used for printing is made larger than the printing energy for the other dots. In addition, the eighth figure shown in Figure 5 (,)
The drive time of the lowest dot of the dot holder may be set to TI depending on the printing situation.

FIG. 6 is a circuit diagram showing a head drive applied voltage switching circuit according to a second embodiment of the present invention. In FIG. 6, heating elements≠1 to +n are arranged in one row in the thermal head 6, and the heating elements=#=1 to ≠n are arranged in drives 1 to 8.
Alternatively, it is connected to drives 1 to 24, and the common sides of heating elements≠2 to≠n are connected to each other. V
D is the head drive supply voltage, the transistor Tri is connected so that it is turned on in the graphics mode, and the transistor Tr2 is connected so that it is turned on in the character mode. The diodes D1 and D2 are connected to have a forward voltage VDf for optimal character printing. R1°R2 are resistances.

Next, the operation of the above configuration will be explained. First, in the case of character printing, the transistor Tr is turned off and the transistor is turned on, so El is connected to the transistor T.
VDIO forward forward voltage drop voltage E1 via r2
is supplied to the heating element≠IK, and R2 is connected to the transistor T
The voltage E2, which is a forward voltage drop of VD2, is supplied to the heating elements +2 to ≠n via r2. Here, since the diodes D1 and D2 are exactly the same, El=E2
becomes.

In addition, in the case of graphics mode, the transistor T
Since r1 is turned on and no forward current flows through diode D1, E] = E2 + VD1 Bz>E2
Therefore, an applied voltage that is greater than the forward voltage VD1 of the diode D+ (t or 112) is applied only to the heating element 1.

Note that the value of E2 is determined by the head drive supply voltage V.
D and diode I)1. It can be adjusted by using the characteristics of D2 or by using 2.3 diodes in series, and is adjusted in advance so that the print density and print size of the raw dots are made uniform by this adjustment.

Therefore, in the second embodiment, by switching the head drive supply voltage VD between character printing and graphic printing, the voltage E1 applied to the first dot is set as E1=E2 during character printing, and when graphics printing is performed. Sometimes El>E2.

In addition, as shown in the circuit diagram of the thermal head in Fig. 7, the common side of heating elements +1 and +n is made common, and the heating element +
By making the common side of 2 to +n-1 common, the printing energy for the first dot and the lowest dot may be made higher than that for other dots.

9-ff and FIG. 8 are configuration diagrams of a thermal head used in a third embodiment of the present invention. In FIG. 8, the thermal head 6 has heating elements +1 to ≠8 or 1 to +24 in one row.
is arranged, and the surface area of this heating element≠1 is larger than that of the other heating elements≠2 to +8 or ≠1 to ≠24, thereby lowering the resistance value and increasing the applied energy J.
2 Here, the relational expression of printing energy m J --T is established. ■: Applied voltage R: Resistance value of the heating element T: Application time ms As shown in the configuration diagram of the thermal head in Figure 9, the surface area of the heating element≠8 or 4P24 is calculated in the same way as the heating element≠1. It may be made larger to lower the resistance value and increase the applied energy.

FIG. 10 is a configuration diagram of a thermal head used in a fourth embodiment of the present invention. In FIG. 10, the thermal head 7 includes heating elements ≠1 to ≠8 or +=1 to +-24 in one row.
Further, a preheating element 7 is arranged near and above the heating element +1. The preheating element 7 is applied at the same time as the heating element ≠ 1 is applied in the case of graphics printing, and the dimensions of the preheating element 7 are made small so that the applied energy at this time is large enough not to cause color development or transfer. Then increase the resistance value.

Therefore, the printing energy for the first dot is greater than the printing energy for the other dots, and the printing density and printing size of the dots are uniform without being affected by the physical arrangement of the dots.

In addition, as shown in the configuration diagram of the thermal head in FIG. 11, a preheating element 7 is also arranged near and below the heating element ≠8 or ≠24, so that the dot printing density and printing by the heating element +8 or ≠24 can be adjusted. The non-uniformity of dimensions may be increased.

〔Effect of the invention〕

As described above, according to the serial thermal printer of the present invention, when performing graphics printing, the printing energy for the first dot or the first dot and the lowest dot is made larger than the printing energy for other dots. Because the print density and print size are uniform without being affected by the physical arrangement of dots, until now it has been difficult to copy a CRT screen.
This has the effect of improving the print quality by eliminating the thin white lines between lines that occur when printing with tweezers.

Further, the present invention has the effect of eliminating small line feed deviations due to play or backlash of gears in the line feed mechanism, and improving horizontal lines.

[Brief explanation of drawings]

FIG. 1 is a flowchart showing a first embodiment of the present invention, FIG. 2 is a perspective view of a conventional thermal head, FIG. 3 is a perspective view of a conventional example, and FIG. 4 is a plan view of a raw point according to a conventional example. , 5th
The figure is a time chart showing the first embodiment of the present invention,
The figure (,) is a time chart with 8 dots, and the figure (b) is a time chart with 8 dots.
) is a time chart with 24 dots. FIG. 6 is a circuit diagram showing a second embodiment of the present invention, FIG. 7 is a circuit diagram showing another aspect of the second embodiment, and FIG. 8 is a configuration diagram showing a third embodiment of the present invention. FIG. 9 is a configuration diagram showing another aspect of the third embodiment, FIG. 10 is a configuration diagram showing the fourth embodiment of the present invention, and FIG. 11 is a configuration diagram showing another aspect of the fourth embodiment. . 6...Thermal head 7...Preheating element 吾】〜＋
n...Heating element VD...Head drive supply power f
fE Trl+Tr2...Transistor Dl,
D2... Diode patent applicant Oki Electric Industry Co., Ltd. Representative Patent Attorney Takashi Kanakura Flow chart of the first embodiment [JT] O] Immediate procedural amendment (, B. November 1985) 15th, Michibe Uga, Commissioner of the Patent Office1, Indication of the case Patent Application No. 151238 of 19852, Title of the invention Printing method for serial thermal printers3, Person making the amendment Relationship with the case Representative of the patent applicant Nankai Hashimoto 4, Agent 6 Subject of amendment Column 1 of “Detailed description of the invention” in Specification 1
drawing. 7. Contents of amendment -h(+・) ``...Transis〆O'' on page 6, line 11 of the specification
N...'' is corrected to [...transistor Tr2 is ONj. 2. Page 7, line 6 of the specification] “...2.: 3 pieces...
・” is corrected to “…multiple pieces…”. 3. In the 6th line of page 8 of the specification, "...or +1~" is corrected to "...or +-2~". 4 Replace “...resistance” on page 6, line 11 of the specification with “・
...resistance value". 5. On page 9 of the specification, line 2, “...simultaneously applied...
" is corrected to "...applied at the same time or a little earlier." 6 Correct Figure 1 as shown in the attached sheet. 7. Correct Figure 6 as shown in the attached sheet. 8 Correct Figure 8 as shown in the attached sheet. Flowchart of the first embodiment 1 B Block diagram of the third embodiment 8 National procedural amendment (voluntary) October 16, 1985 Commissioner of the Japan Patent Office Black 1) Akio Tono 1, Indication of the case 1988 Patent Application No. 151238 2, Title of the invention Printing method of serial thermal printer 3, Relationship to the case of the person making the amendment Patent applicant address 1-7-12 Toranomon, Minato-ku, Tokyo Name (029) Oki Electric Industry Co., Ltd. Company representative Nankai Hashimoto 4o Agent 5 Date of amendment order (voluntary) 6 Subject of amendment Drawing 7 Contents of amendment ■ Figure 6 will be amended as shown in the attached sheet.

Claims (1)

[Claims] 1. In the printing method of a serial thermal printer that prints on a print medium using a thermal head in which a plurality of heating elements are arranged in an array, the printing energy of the first dot or the first dot and the lowest dot is , a printing method for a serial thermal printer characterized by having a printing energy greater than that for other dots.