JPH02266963A - Thermal printer protection device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a device for protecting a thermal printer, which is used for control signals such as printing pulse signals of a thermal head, for example.

BACKGROUND ART When printing using a thermal head, for example, printing data is generally set in the thermal head in advance, and printing is performed by causing the thermal head to generate heat for a certain period of time by outputting a printing pulse signal for a certain period of time.

FIG. 4 shows an example of the configuration of a conventional thermal printer. Fourth
The central processing unit (hereinafter referred to as CPU) in the figure first transfers print data to the υ thermal head 6 via a data line, and then controls the control signal output circuit 2.
Outputs of control signals A,' (hereinafter referred to as signals A1') and A2' as shown in FIG. 5 are obtained. This output is passed through the buffer 7 as conventional thermal printer printing pulse signals C1' (hereinafter referred to as signal 01') and 02 in FIG.
' output, and by inputting it to the thermal head 6, print data set in advance on the thermal head e is printed.

Although FIG. 4 shows a thermal head e divided into two blocks, the thermal head is generally divided into one or more blocks, and the required number of blocks is controlled in the same way.

Problems to be Solved by the Invention In the above-mentioned conventional system, due to runaway or malfunction of the CPU, the signals A and ' in Fig. 6 become solid lines instead of broken lines, and the signals A and '! Similarly, -01' remains in the output state. This has the disadvantage that the heating element of the thermal bed becomes overheated, which may cause deterioration or damage to the thermal head.

Means for Solving the Problems In order to solve the above problems, the thermal printer protection device of the present invention includes a control signal output circuit that is connected to a CPU and outputs a control signal, and an output timing that detects the output timing from this output signal. The configuration includes a detection circuit, an output permission circuit that creates an output permission signal for a certain period of time from the output from the output timing detection circuit, and a thermal printer print pulse signal that is created by ANDing this output permission signal and a control signal. It is prepared.

With this configuration, in order to detect the output timing from the control signal, the output permission signal is sent for a certain period of time, which is longer than the output control signal and which is long enough to not cause deterioration or damage to the thermal printer device. Furthermore, by gated with a control signal, it is possible to control the output time of the printing pulse signal of a thermal printer such as a thermal V head so that it does not exceed a certain period of time.
can protect your thermal printer.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to FIGS. 1, 2, and 3. Note that the same components as in FIG. 4 are given the same numbers.

As shown in FIG. 1, the CPU 1 first transfers print data to the thermal bed e using data @D, and then controls the control signal output circuit 2 to generate the control signal A1 (hereinafter referred to as signal A1) in FIG. and A2 (hereinafter referred to as signal A2). The output timing detection circuit 3 detects the output timing, that is, the rise timing of the signal A and the signal A2, and outputs the trigger signal E to the output permission circuit 4. The output permission pulse signal B (hereinafter referred to as signal B) shown in FIG. By inputting signal A and signal B1 and signal A2 and signal B to gate 6, thermal printer printing pulse signals C1 (hereinafter referred to as signal C1) and C2 shown in FIG. 2 are created and input to the thermal head e. By doing this, the print data set in advance on the thermal pad 6 is printed.

If the signal A is supposed to fall at the timing shown by the broken line, but due to some malfunction, the output becomes as shown by the solid line, the signal B and the gate 6 can cause the υ signal C1 to fall after a certain period of time. . This prevents the thermal head e etc. from deteriorating or being damaged. Although FIG. 1 shows the case where the thermal head 6 is divided into two blocks, in the case of a thermal head consisting of a single block or a plurality of blocks, the corresponding input can be inputted to the output timing detection circuit 3, and a gate 6 can be added. It becomes possible to deal with this.

Furthermore, by configuring the output permission circuit 4 with a monostable multivibrator for retry, even if the output timing interval of signal A1 is shorter than the output time of signal B, as shown in FIG. When the signal B does not fall and is output again as shown by the solid line, the signal C1 can be obtained, and the signal B can be used as it is set for a certain period of time.

Effects of the Invention As described above, the present invention includes a control signal output circuit connected to a CPU that outputs a control signal, an output timing detection circuit that detects an output timing from this output signal, and an output from the output timing detection circuit. An output permission circuit that creates an output permission signal for a certain period of time, and a thermal printer print pulse signal created by the AND of this output permission signal and a control signal, prevents CPU runaway, malfunction, and CPU operation stoppage during development. occurs, and the signal A in Fig. 2,
Even if the signal B does not fall at the timing shown by the broken line and the output is as shown by the solid line, the signal B and the gate 6 in Figure 1
Therefore, the signal C1 can fall after a certain period of time. As a result, the thermal printer can be protected from deterioration or damage to the thermal head due to heat generation, which is very effective in terms of safety.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a thermal printer of the present invention, FIG. 2 is a signal time chart of the device of the present invention, FIG. 3 is a signal time chart of the device of the present invention, and FIG. 4 is a block diagram of a conventional thermal printer. Figure S is a signal time chart of a conventional device. 1...C! PU, 2... Control signal output circuit, 3... Output timing detection circuit, 4...
...Output permission circuit, 6...Gate, 6...
...Thermal head, 7...Buffer, A
,... Control signal, B... Output permission pulse signal f, C,... Thermal printer printing pulse signal, A'... Conventional control signal, C4'...
・・・Conventional Suichimaru printer printing pulse signal, D...
...Data line, E...Trigger signal, A2.
... Control signal, C2 ... Thermal printer printing pulse signal, A2' ... Conventional control signal, 02' ... Conventional thermal printer printing pulse signal.

Claims (1)

[Claims] A control signal output circuit that is connected to the CPU and outputs a control signal, an output timing detection circuit that detects output timing from this output signal, and an output permission that creates an output permission signal for a predetermined time from the output from this output timing detection circuit. A protection device for a thermal printer, comprising a circuit, and creating a thermal printer printing pulse signal by ANDing the output permission signal and the control signal.