JPH01294067A - Thermal recording printer - Google Patents

Abstract

PURPOSE:To eliminate a delay in printing speed at the time of low temperature, by controlling a head applied energy through a control means by the output of a head temperature-detecting thermistor and by transmitting head-preheating data to a thermal head at the time of said low temperature. CONSTITUTION:A printing control circuit 8 inputs line data from a printing data receiver 17 into an adjoining control circuit 8 and a previous history control circuit 7, controls the pulse width of an applied energy according to the drive or not drive of an adjacent heating element 2 and a previous history, and selectively drives each heating element 2 of a thermal head part 1. Also, an applied pulse controller 26 transmits to a printer controller the temperature information of a pulse output corresponding to a head temperature detected by a thermistor 25. As the time of detecting that the head temperature is lower than a constant value, then, said controller 26 makes self-printing data black and causes the heating element 2 of said thermal head part 1 to self-generate heat, so as to keep the thermal head part 1 at a temperature not lower than said constant value. Thus, it is possible to place a limitation on the maximum applied pulse width and the printing speed of an apparatus is prevented from becoming slow at the time of low temperature.

Description

[Detailed description of the invention] Industrial applications The present invention relates to thermal recording printers.

Conventional thermal recording methods are easy to maintain and are used in printers for many terminals, including facsimile machines.In recent years, thermal transfer methods have also been developed, making multicolor or full-color recording possible.

Conventionally, in thermal recording links using this type of thermal recording method, in order to obtain sufficient density at low temperatures, the required density has been obtained by increasing the pulse width applied to the thermal head.

Problems to be Solved by the Invention This conventional configuration has a drawback that the printing time becomes longer than that at room temperature due to the increase in the applied pulse width.

The present invention is intended to solve these conventional problems, and aims to prevent printing time from increasing at low temperatures.

Means for Solving the Problems In order to solve these problems, the present invention provides a thermal head, a head temperature detection thermistor for detecting the temperature of the thermal head, and a head temperature detection thermistor for detecting the temperature of the thermal head. The thermal recording printer has a control means for controlling applied energy and a transfer means for transferring head preheating data to the thermal head.

Effect With this configuration, the head temperature can be maintained above a certain level before starting the printing operation at low temperatures, so the printing time does not become long at low temperatures.

Example An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the circuit configuration of a thermal printer according to an embodiment of the present invention. In the figure, 1 is a thermal head section, and this thermal head section 1 is arranged in a line on an insulating substrate. A heating element 2 which is a thermal head consisting of a plurality of heating resistors arranged in N units and electrically divided into N units, and a heating element 2 provided for each unit of this heating element 2. It is composed of N driver circuits 3, N latch circuits 4 provided corresponding to each of the driver circuits 3, and N shift registers 6 provided corresponding to each of the latch circuits 4. There is.

In this thermal head section 1, one electrode of the heating elements 2 is connected in common to a printing power source, and the other electrode is connected to an output terminal of a driver circuit 3. In addition, the input terminal of the driver circuit 30 is connected to the latch circuit 4.
The input terminal of the latch circuit 4 is connected to the output terminal of the shift register 5, and the print data signal input to each shift register 6 is output as a parallel signal to the corresponding latch circuit 4. The driver circuit 3 is driven by the print data signal sent from the latch circuit 4, and the heating element 2 corresponding to the print data signal is energized to perform thermal recording. Here, each of the driver circuits 3 is configured so that an enable signal for controlling the operation of the driver circuit 3 is applied to each driver circuit 3 independently and in parallel.

6 is a printing control circuit section, and this printing follicle circuit section 6 includes an antecedent history control circuit 7, an adjacent control circuit 8, and an application pulse control section 26.
It is composed of.

The previous history control circuit 7 includes a data selector 9 that outputs the print data signal to the shift register 6, and a multi-ITD whose output terminal is connected to one input terminal of the data selector 9.
It consists of a gate 10 and an inverter 11 connected to one input terminal of the ND game 10.

Further, the adjacent control circuit 8 includes an OR gate 12 whose output terminal is connected to the inverter 11 of the previous history control circuit 7, and this O
A 2-bit shift register 13 connected to one input terminal of the R gate 12, a MND gate 14 whose output side is connected to the other input terminal of the OR gate 12, and this M
It is composed of a shift register 16 that applies a signal directly to the input terminal of the D gate 14 and via an inverter 15.

Further, in this print control circuit section 6, a previous history control circuit 7
The other input terminal of the data selector 9 is the ND gate 1.
The output terminal of the shift register 16 of the adjacent control circuit 8 is connected to the other input terminal of the control circuit 8. Further, one input terminal of the ND gate 14 is connected to the input side of the shift register 16.

Reference numeral 17 denotes a print data receiving section, which is composed of three line buffer memos 1J18, 19, and 20, a reading buffer selector 21, and a reading buffer selector 22. In this print data receiving section 17, 3
Of the two line buffer memories, one line is used for reception, and the remaining two lines are used for printing. That is, when the reception and printing of one line is completed, the role of the memory is switched and the next line is received and printed.

Table 1 shows this situation.

(Left below) In a thermal recording printer with such a configuration, the print data signal input to the read buffer selector 21 of the print data receiving section 17 is sent to the line buffer memories 18 and 19.
,20. It passes through the read buffer selector 22 and is sent to the adjacent control circuit 8 of the print control circuit section 6 .

This adjacent control circuit 8 controls the applied energy depending on the presence or absence of adjacent print data on the heating element 2.
When the print data of two adjacent dots on both sides is 6", the print data of the previous line is set to 99", so that the previous history control circuit 7 does not operate. In addition,
In the circuit shown in Figure 1, “°°white” is set to high level (6).
, °°Black' is set as the low level (L). Therefore, when the print data of the 2 dots on both sides is 1 White, that is, the print data of the current line is stored in the shift register 16 as ``H, H, L''.
,H.

When lined up with "H", it works to change the print data of the previous line to "white", that is, "H", and it is possible to print a single vertical line more clearly than K.

The print data controlled by this adjacent control circuit 8 is
It is sent to the previous history control circuit 7.

This previous history control circuit controls the energy applied to the heating element 2 when printing the next line based on the print data of the previous line.
When printing data of , the residual heat remains in the heating element, so when printing the next line, the energy applied to the heating element 2 must be reduced by the amount of residual heat, otherwise excessive energy will be applied. , it becomes impossible to obtain prints with good density. In order to prevent this problem, the previous history control circuit A controls the pulse width of the energy applied to the heating element 2 for each dot based on the print data of the previous line. Note that in a printer with a line-type head unit like the present invention, it is difficult to control the applied pulse for each dot, so it is necessary to transfer two lines of print data in order to print one line. As a result, the pulse width of the energy applied to the heating element 2 is controlled depending on whether printing is performed twice or twice. Table 2 shows an example of control in this previous history control circuit 7. In addition, previous history control data (
2@i-th print data) is output according to Table 3. Note that in the circuit shown in Figure 1.

The circuit is configured so that "white" becomes "H" and "black" becomes "L".

(Left below) The print data controlled by this previous history control circuit 7 is
The signal is input to the shift register 6 of the thermal head section 1.

The print data signal input to the shift register 6 is input to the driver circuit 3 through the latch circuit 4, and the driver circuit 3 controls the energization of the heating element 2 based on the print data signal and the enable signal. The heating element 2 selectively generates heat to perform predetermined printing.゛Here, in this embodiment, since the configuration is such that enable signals are input independently and in parallel to each of the driver circuits 3, even if print data controlled by the previous history is continuously applied, the printing may be shifted. There is no. Sunawa υ,
When performing previous history control as described above, it is necessary to send two pieces of data as shown in FIG. 2 for one line of printing. Second
In the figure, the times of M and C change depending on the head temperature, and are controlled so that appropriate energy is applied. However, when printing 4 sizes of M in 1 minute, using a head with a heating element divided into 7 Then, the time of C is 700 μs at maximum.
・The time will be C, and the time of M will be at least 260 μsec.
It becomes a.

In the head section where such prior history control data is input, if an enable signal is input in parallel to each of the driver circuits 3 independently, when using a 7-division head of 8 dots/H and the size of 4-print printing, The number of dots per block is 224, so the data transfer time is 2
24μsea, the minimum value of the above-mentioned time is 250μ
Since it is within seC, printing data can be applied continuously and no deviation occurs in printing.

Reference numeral 23 denotes a printer control section composed of a microcomputer, which has a function of reading head temperature and a function of outputting self-printing data for head preheating. The self-print data output from the printer control section 23 is sent to the print data receiving section 17 via the data selector 24.

On the other hand, a head temperature detection thermistor 26 built into the thermal head is connected to the applied pulse control section 2e and outputs a pulse corresponding to the head temperature. This pulse output is then given to the printer control section 23 as head temperature information.

In the thermal recording printer configured as described above, in the present invention, when it is detected that the head temperature is lower than a certain value, the self-printing data is transferred to the thermal head section 1 as "°° black", and the thermal head section By causing the heating element 2 to generate heat by itself, the thermal head section 1 can always be kept at a temperature above the -room, and there is no need to slow down the printing speed at low temperatures.

Effects of the Invention As described above, according to the present invention, by keeping the head temperature above a certain level, the maximum applied pulse width can be limited, so that the printing speed does not slow down at low temperatures.

[Brief explanation of the drawing]

FIG. 1 is a block circuit diagram showing the circuit configuration of a thermal recording printer according to an embodiment of the present invention, and FIG. 2 is an explanatory diagram for explaining the control operation of the main parts of the circuit. 1...Thermal head section, 2...Heating element, 3...Driver circuit, 4...
Latch circuit, 6゜13.16...Shift register, 6...Print control circuit section, A...Previous history control circuit, 8...Adjacent control circuit , 9...
...Data selector, 10.14...MND game), 11.15...Inverter, 12...
...OR gate, 17...Print data receiving section, 18゜19.20...Line buffer memory, 21...Read buffer selector, 22...
... Read buffer selector, 23 ... Printer control unit, 24 ... Data selector, 26
...Thermistor, 26... Applied pulse control section. Name of agent: Patent attorney Toshio Nakao and 1 other person 2nd
figure

Claims (1)

[Claims] a thermal head, a head temperature detection thermistor for detecting the temperature of the thermal head, a control means for controlling the energy applied to the thermal head based on the output of the head temperature detection thermistor, and a head preheating data for the thermal head. A thermal recording printer having a transfer means for transferring.