JPH05104765A - Heat control device of thermal printer - Google Patents

Abstract

PURPOSE:To perform a high quality printing having no density irregularity at every dots without exerting effect on a printing speed and to prevent the generation of the deterioration of life due to overheating. CONSTITUTION:The printing data of a past line and the printing data of a present line are read from a memory device 2 to be subjected to comparative operation in an operation circuit 3 and the control data of the operation result is subjected to time sharing processing to be inputted to a line thermal head 4 in synchronous relation to a clock 5 and, for example, at the first time, dots are preheated excepting previously printed and heated dots and, at the second time, the preheating of dots at both ends is performed when printing data continue and, at the third time, the heating of all of printing data is performed to keep the temp. balance of all of dots.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal controller of a thermal printer of a thermal type and a thermal transfer type, which uses a thermal head of a line.

[0002]

2. Description of the Related Art In a conventional thermal printer, printing is performed by heating a line thermal head for a certain period of time, or heating of a line thermal head is performed by a heating voltage or heating time depending on the presence or absence of past print data or a pattern. It is known to have a thermal control device controlled by.

[0003]

However, in the conventional thermal type and thermal transfer type thermal printers, printing is performed by heating the thermal head of the line for a certain period of time. As a result, the temperature of the thermal heads on the line fluctuates, and the print density is not constant, which causes a problem in print quality. For more information,
When printing is not performed in the past line at all and printing is performed in the current line for the first time, the line thermal head is in a cold state, and thus insufficient heating occurs. If the printing time is lengthened in order to compensate for the insufficient heating, the continuous heating of the past line and the present line will result in overheating. Further, when printing is continuously performed in one line, there is a problem in that since the temperature of the heating element elements (hereinafter referred to as dots) at both ends is lower than that in the central portion, there is a difference in printing density, which causes shading.

In addition, the one that changes the heating time and the voltage depending on the presence or absence of printing of the lines before and after the current line and the pattern,
It takes time because not only the search of print data and the calculation of print data but also the calculation of heating time and voltage are performed by software.
There was a problem that it was not suitable for high-speed printing.

In view of the above problems of the prior art, the present invention provides a thermal control device for a thermal printer, which can obtain high-quality printing with no print shading without impairing the printing speed and does not shorten the life due to overheating. The purpose is to provide.

[0006]

In order to achieve the above-mentioned object, the present invention uses storage means for storing print data and adjacent print data to extract both ends of the print data, and also to print one or more lines before. An arithmetic circuit that uses the print data and the print data of the current line to retrieve the print data that is printed in the current line without being printed one or more lines before, control data that emphasizes both ends of the print data, and one line Control data that emphasizes the print data that is not printed before and is printed on the current line,
The present invention is characterized by further comprising means for time-dividing the control data of the current print data within one line of print time and synchronizing the clock data with the clock and inputting them to the thermal head of the line.

[0007]

According to the present invention, the operation by software is not required to create the control data, and the preheating is performed by changing the number of times the dots are heated within the printing period of one line based on the control data obtained from the arithmetic circuit. Since printing is performed after printing, the temperature for printing each dot is constant, the printing speed is not impaired, the density of printing is eliminated, the printing quality is improved, and it is possible to easily control to prevent overheating, The life of the thermal head in the line can be extended.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a thermal control device for a thermal printer according to the present invention will be described below with reference to FIGS.

In FIG. 1, which shows a block diagram of a main part of a thermal control device of a thermal printer, 1 is a 16-bit CPU.
The print data stored in the storage device 2 using a dynamic random memory (DRAM) is read out. The read print data is input to the arithmetic circuit 3. The CPU 1 selects control data to be sent to the thermal head 4 of the line from the data calculated by the arithmetic circuit 3. The selected control data is input to the thermal head 4 of the line in synchronization with the clock signal 5 to perform preheating or heating.

FIG. 2 shows one specific example of the arithmetic circuit 3.
In the present embodiment, one word has 16 bits and one line has 40 words for 640 bits. However, in order to simplify the description in FIG. 2, the current line and the 0th and 1st words of the previous line are printed. Data is used, and one word has a 5-bit structure.

In FIG. 2, Dhij (two digits) represents the print data of the j-th bit of the i-th word before the h-th row. For example, Dhi00 represents the least significant bit of the i-th word of the print data before the hth row, and D0001 represents the first bit from the least significant of the 0th word of the current row.

An example of the calculation method will be described. First, D1100 to D1104, which is the print data of the first word one row before, is output from the storage device 2, and the signal L of the CPU 1 is output.
1 latches by using the latch circuit 10b.

Next, the print data D0100 to D0104 5 of the first word of the current line output from the storage device 2 is output.
The bits are input to the logical product elements 6a to 6e of three inputs, the obtained outputs are inverted by the inversion elements 7a to 7e, and are input to the selection circuit 8 as control data. This control data is control data that emphasizes both ends of the print data. Since D0100 and D0101 need to be calculated using D0003 and D0004 that are one word before, Dhi03 and Dhi04 (h and i are arbitrary numbers) are input to the latch circuit 10a, and the latch signal of the CPU1 is input. L
Latched by 2. Although not shown in order to avoid complication, in the circuit configuration of FIG. 2, both-end detection data is shifted by one bit, so this is advanced by one bit, and the detection data is detected even in a portion without print data. Since it is output, it is output to the selection circuit 8 via a processing circuit that performs a logical product with the print data of the current line.

D1100 to D11 latched simultaneously
04 inverted by inverting elements 11a to 11e and D
0100 to D0104 are logical product elements 12a to
The data obtained by 12e is input to the selection circuit 8 as control data. This control data is control data that emphasizes the print data that is not printed one line before but is printed in the current line.

Further, the print data of D0100 to D0104 is directly input to the selection circuit 8.

The input three signals are converted into the signal S of the CPU 1
Select by. The print data selected by the selection circuit 8 is converted into serial data by the parallel-to-serial conversion circuit 9 in parallel input / serial output in synchronization with the clock signal of the thermal head 4 of the line, and is input to the thermal head 4 of the line. To do.

FIG. 3 is a model diagram showing a portion of the print data. The white background portion is the portion where the data 0 is not printed and the shaded portion is the portion where the data 1 is printed. .. (A) is the print data of the previous line,
(B) is print data of the current line. (C) is control data which is the logical product of the inverted print data (a) of the previous line and the print data (b), and (d) is both ends of the shaded portion of the print data (b) of the current line. Is the control data extracted.

First, by the read cycle of the CPU 1, the 16-bit data of the print data D1000 to D1015 of the 0th word, which is the print data of the preceding line shown in (a), is read from the storage device 2 and the latch circuit 10b is set. It is latched by using the latch signal L1. Next, print data D00 of the 0th word of the current line shown in (b)
16-bit data from 00 to D0015 is read from the storage device 2. These data are input to the arithmetic circuit 3, and the control data (c) and (d) which are the arithmetic results and the original print data (b) are input to the selection circuit. At the same time, the print data of D0014 and D0015 is latched by the latch circuit 1
0a is used to latch by the latch signal L2. In the selection circuit 8, the control data (c) which is the calculation result is first obtained.
Is selected by the signal S from the CPU 1, converted into serial data by the parallel-serial conversion circuit 9, and input to the thermal head 4 of the line in synchronization with the clock. 40 this
Preheat after repeating a word. Next, in the selection circuit 8, the control data (d) as the calculation result is selected by the signal S from the CPU 1, converted into serial data by the parallel-serial conversion circuit 9, and input to the thermal head 4 of the line in synchronization with the clock. To do. This is repeated for 40 words and then preheated. Furthermore, the print data of the current line (b)
Is selected and converted into serial data by the parallel-serial conversion circuit 9 and input to the thermal head 4 of the line in synchronization with the clock, and this is repeated for 40 words and then heated.

In other words, the print data of the current line is preheated except for the dot which was printed and heated one line before. Further, if print data of 3 dots or more continues in the direction adjacent to the current line, the dots at both ends of the print are preheated. And finally, the current row is heated. In this way, heating is performed after preheating twice, then the paper is advanced to the next row, and preheating and heating for printing of the next row are performed. As a result, the dot whose print data was 0 one line before was preheated and heated once to prevent insufficient heating, and the dot whose print data was 1 before one line was heated once. Excessive heating can be prevented only with this.
In addition, the dots at both ends of the print data 1 are preheated and heated once to prevent blurring of the outline due to insufficient heating, and continuous dots are heated only once, so overheating does not occur in the line. The life of the head 4 is extended.

In the above embodiment, the data is selected by the signal S from the CPU 1 and the print data is latched by the signals L1 and L2. However, a circuit for producing the signals S, L1 and L2 is provided in the thermal control circuit. You can also

[0021]

According to the thermal control device of the thermal printer of the present invention, by adding some circuits, printing is performed by changing the heating frequency of each dot according to the printing state within one line printing period. Therefore, without impairing the printing speed,
The temperature at the time of printing each dot of the thermal head of the line can be kept constant, the density of printing is eliminated, the printing quality is improved, and the head is not overheated, so the life of the thermal printer of the line can be extended. ..

[Brief description of drawings]

FIG. 1 is a block diagram of a main part of a thermal control device of a thermal printer according to an embodiment of the present invention.

FIG. 2 is a circuit diagram showing an example of an arithmetic circuit in the thermal controller of the embodiment.

FIG. 3 is an explanatory diagram of print data and control data according to the same embodiment.

[Explanation of symbols]

 1 CPU 2 memory device 3 arithmetic circuit 4 line thermal head 5 clock signal

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Manabu Eguchi 1006 Kadoma, Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Naoki Hatada, 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd.

Claims (1)

[Claims] 1. A storage means for storing print data, and both ends of the print data are extracted by using adjacent print data, and print data of one or more lines before and print data of the current line are read by one or more lines before. The operation circuit that retrieves the print data that is printed on the current line without being printed on, the control data that emphasizes both ends of the print data, and the print data that is printed on the current line without being printed one or more lines before Control data that emphasizes
A thermal control device for a thermal printer, comprising: means for inputting to the thermal head of the line in synchronism with a clock by time-sharing the control data of the current print data within one line of printing time.