JP3043042B2 - Thermal printer and print processing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Table of Contents] Overview Industrial application field Conventional technology (FIGS. 6 to 8) Problems to be solved by the invention (FIG. 9) Means for solving the problems (1st. Figure) Action Embodiment (FIGS. 2 to 5) Effects of the Invention [Overview] Regarding a thermal printer, in particular, a protection function of a heating element for performing thermal printing on thermal paper, a part for performing print monitoring processing of the heating element Without increasing the number of points, the malfunction of the external circuit, the runaway of the control system, etc. are monitored on the software of the print control program, and based on this, a heating element selection signal is output to protect the heating element. In order to reduce the cost of the apparatus, the printer includes a thermal paper moving unit that supplies thermal paper, a thermal head including a plurality of heating elements for printing on the thermal paper, and a thermal head. Output heating element selection signal A thermal head drive control means for controlling the thermal head drive control means, a signal monitoring means for monitoring a print control program of the thermal head drive control means, and a control means for controlling input and output of the thermal paper moving means and the thermal head drive control means. In the printer, the thermal head drive control unit includes a first control unit that monitors runaway of the print control program.
A first signal generating means for generating a first control signal having a pulse width of ??, and a second signal generating means for generating a second control signal having a second pulse width for driving the thermal head. It is configured to include.

[Industrial applications]

The present invention relates to a thermal printer and a print processing method thereof, and more particularly, to a protection function of a heating head for performing thermal printing on thermal paper and a print monitoring method.

2. Description of the Related Art In recent years, printing apparatuses using thermal paper or the like as a recording medium (hereinafter referred to as a thermal printer) have been used.

According to this, there is a demand for a thermal printer capable of protecting a heating head from malfunction of an external circuit and runaway of a control system print program, and a print processing method therefor.

[Conventional technology]

 6 to 9 are explanatory diagrams according to a conventional example.

FIG. 6 shows a configuration diagram of a thermal printer according to a conventional example.

In the figure, a thermal printer that performs thermal printing on thermal paper 10 includes a CPU 1, a motor drive control circuit 2, a motor 3, a platen 4,
It comprises an interface 5, a data buffer 6, a character pattern generation circuit 7, a print processing monitoring circuit 8, and a thermal head 9.

The function of the thermal printer is as follows. First, the thermal paper 10 is inserted between the thermal head 9 and the platen 4, and the thermal paper 10 is sequentially fed through the motor 3 connected to the platen 4. Next, for example, serial data Din is output from the data buffer 6 and the character pattern generation circuit 7 to the print processing monitoring circuit 8 based on the external input data DIN input to the interface 5, and the heating element is selected based on the data Din. The signal TRi is input to the thermal head 9. As a result, heat is supplied to the thermal paper 10 between the thermal head 9 and the platen 4, and printing can be performed on that portion.

FIG. 7 is a configuration diagram of a print processing monitoring circuit according to a conventional example.

In the figure, a print processing monitoring circuit 8 for protecting the heating resistors R1 to Rn from malfunctioning of an external circuit or runaway of a control system printing program includes a microprocessor (hereinafter referred to as MPU) 8
A, a one-shot timer circuit 8B and a logical sum inversion output circuit NA1 to NAn.

Its function is to perform two-input NAND logical operation processing on a print timing signal TX activated by using a print control signal SI from the MPU 8A as a trigger signal and a heating element selection signal TR1 to TRn obtained by signal processing of serial data Din. Heating resistor R1 ~
Output to Rn.

For example, when a heating element selection signal TRIi = “H” level is continuously output to a certain heating resistor Ri due to a malfunction of an external circuit or a runaway of a control system print program, the one-shot timer circuit 8B Generated print timing signal TX
, The driving current flowing through the heating resistor Ri is interrupted. Thereby, the heating resistor Ri is protected.

FIG. 8 is a flowchart of a print processing method according to a conventional example, and shows, for example, an operation flowchart of the MPU 8A of the print processing monitoring circuit 8.

In the figure, when performing the thermal printing process on the thermal paper 10 by performing selection control of the plurality of heating resistors R1 to Rn based on the serial data Din, first, an initial setting process is performed in Step P1, and then, in Step P2. The serial data Din is read by data processing “Busy = L”, and the data Din is read in step P3.
Judge input. At this time, if the input is completed (YE
In S), the reading process is terminated by the data process “Busy = H” in step P4.

In step P5, it is determined whether the input processing of the serial data Din is completed. At this time, if the input processing is completed (Y
In ES), a heating resistor selection process is performed in step P6, and a resistor driving timer is started in step P7. As a result, a drive current flows through the selected heating resistance element Ri, and heat is generated to supply heat to the thermal paper 10.

After that, in Step P8, the termination of the resistor driving timer is determined. At this time, if the timer expires (YES),
At step P9, a heating element selection signal TRi to the heating resistors R1 to Rn.
Is turned off, and the drive stop processing is performed.

Thereafter, it is determined in step P10 that one-line printing has been completed, in step P11 that printing has been completed, and in step P12 that control processing has been completed.

[Problems to be solved by the invention]

By the way, according to the conventional example, as shown in FIG. 9, the energizing time during which the drive current flows through the heating resistance element Ri, that is, the heat supply time to the thermal paper 10, is determined by the heating element selection signals TR1 to TRn from the MPU 8A. It depends on the duration of the "H" level.

For this reason, the heating element selection signals TR1 to TRn may continue for a long time at the "H" level due to malfunction of an external circuit due to external noise, runaway of a control system printing program, or the like. Ri intermittently generates heat. Further, when the heat storage amount increases, burning may occur. This depends on the signal duty ratio (for example, H: L = 7: 3) between the “H” level period and the “L” level period of the print timing signal TX generated by the one-shot timer circuit 8B. This is because the driving current flowing through Ri is intermittent, and the heating resistor Ri generates abnormal heat.

Note that the duty ratio of the print timing signal TX depends on the relationship between the heat generation characteristics (heat generation and heat radiation characteristics) of the heat generating resistor Ri, for example,
It cannot be set to a small value because of the amount of heat for performing the optimal thermal printing process on the thermal paper 10. In addition, such a print time monitoring method requires a one-shot timer circuit 8B connected to the outside of the MPU 8A and a plurality of logical sum inversion output circuits NA1 to NAn.

As a result, precious print information is lost due to abnormal heating of the heating resistor Ri, and printing processing with high resolution cannot be performed. As a result, there is a problem that the reliability of the thermal printer is reduced and that the thermal printer is hindered from being reduced in cost.

The present invention has been made in view of the problems of the conventional example, and prints out malfunctions of an external circuit or runaway of a control system without increasing the number of components for performing print monitoring processing of a heating element. A thermal printer and a print processing method for monitoring a software program of a control program and outputting a heating element selection signal based on the monitoring program to protect the heating element and reduce the cost of the apparatus. For the purpose of providing.

[Means for solving the problem]

The thermal printer of the present invention, as shown in FIG.
A thermal paper moving means 11 for supplying thermal paper 16, a thermal head 12 comprising a plurality of heating elements R1, R2, Ri, Rn for printing on the thermal paper 16, and a heating element selection signal to the thermal head 12; Thermal head drive control means for outputting TRi
13, a signal monitoring means 14 for monitoring the print control program of the thermal head drive control means 13, and a control means 15 for controlling the input and output of the thermal paper moving means 11 and the thermal head drive control means 13, The thermal head drive control means 13 counts the number of each processing routine of the print control program and determines whether the execution state of the print control program is good or not.

In the thermal printer, the signal monitoring means 14 outputs an operation release signal RST for initializing the print control program based on the monitored signal TPR from the thermal head drive control means 13. .

A thermal paper moving means 11 for supplying thermal paper 16;
A plurality of heating elements R1, R2, R for printing on the thermal paper 16
i, Rn; a thermal head drive control means 13 for outputting a heating element selection signal TRi to the thermal head 12; a signal monitoring means 14 for monitoring a print control program of the thermal head drive control means 13. A control means 15 for controlling the input and output of the thermal paper moving means 11 and the thermal head drive control means 13. A first pulse for monitoring runaway of the print control program is provided to the thermal head drive control means 13. A first signal generating means 13A for generating a first control signal S1 having a width φ1, and a second signal generating means for generating a second control signal S2 having a second pulse width φ2 for generating the heating element selection signal (TRi). Signal generation means 13B, the pulse width φ1 of the first control signal S1 is longer than the pulse width φ2 of the second control signal S2, and
The priority of the interrupt of the signal generating means 13A is given priority over the priority of the interrupt of the second signal generating means 13B.

Further, the thermal paper moving means 11 for moving and supplying the thermal paper 16
And a plurality of heating elements R1, R for printing on the thermal paper 16.
2, a thermal head 12 comprising Ri, Rn, a thermal head drive control means 13 for outputting a heating element selection signal TRi to the thermal head 12, and a thermal head drive control means
Signal monitoring means 14 for monitoring the print control program 13;
Thermal paper moving means 11 and thermal head drive control means
Control means 15 for controlling the input / output of the heating element element 13 based on the print data Din while monitoring the print control program of the thermal head drive control means 13.
1, R2, Ri, and Rn are selected, and printing is performed on the thermal paper 16 based on the selection.

[Action]

According to the thermal printer of the present invention, as shown in FIG. 1, the thermal paper moving means 11, a plurality of heating elements R1, R2, Ri, Rn.
A thermal head 12, a thermal head drive control means 13, a signal monitoring means 14 and a control means 15 are provided. The drive control means 13 is provided with first and second signal generation means 13A.

For example, when printing is performed on the thermal paper 16 which is moved and supplied by the thermal paper moving means 11, a plurality of heating elements R1, R2, R
The thermal head drive control means 13 sends a second control signal S2 having a second pulse width φ2 to the thermal head 12 comprising i, Rn.
Is output based on the heating element selection signal TRi. At this time,
The print control program of the thermal head drive control means 13 is monitored by the signal monitoring means 14.

That is, the signal monitoring means 14 constantly monitors the monitored signal TPR generated when the thermal head drive control means 13 executes the print control program. For example, the monitored signal TPR is a signal generated when the thermal head drive control means 13 executes the print control program. If the signal TPR becomes abnormal due to malfunction of an external circuit or runaway of the control system, the print control signal TPR Operation release signal R for initializing the program
ST switches from signal monitoring means 14 to thermal head drive control means 13
Is output to

For this reason, the output processing of the heating element selection signal TRi itself for controlling the timing of supplying heat to the thermal paper 16 is stopped, and the drive current flowing through all the heating element R1, R2, Ri, Rn can be turned off. Become. Note that the pulse width φ1 of the first control signal S1 is
Is longer than the pulse width φ2 of the second control signal S2, and
Since the order of interruption of the first signal generating means 13A has priority over the order of interruption of the second signal generating means 13B,
The reset operation in a normal state can be prevented.

As a result, compared to the conventional printing time monitoring method, the heating elements R1, R2,
Ri and Rn can be sufficiently protected.

Further, according to the print processing method of the present invention, the heating element R1, R2, Ri, based on the print data Din while monitoring the print control program of the thermal head drive control means 13.
Rn is being selected.

For example, the monitoring processing is performed by a thermal head drive control unit.
By 13, recognition processing is performed based on the count processing of each processing routine number of the print control program.

Therefore, when the number of processing routines, such as the input / output line level detection processing, the heating element selection processing, the runaway monitoring timer activation processing, and the heating element driving timer activation processing, does not reach or exceeds a preset count, In this case, initialization is performed without shifting to the printing process. This makes it possible to monitor software runaway of the print control program caused by a malfunction of the external circuit.

This eliminates the need for the one-shot timer circuit 8B and the plurality of OR-inverted output circuits NA1 to NAn used in the conventional print time monitoring method, thereby reducing the number of components for performing print monitoring processing of the heating element. And the cost of the printer can be reduced.

〔Example〕

Next, an embodiment of the present invention will be described with reference to the drawings.

2 to 5 are explanatory views of a thermal printer according to an embodiment of the present invention and a print processing method thereof, and FIG. 2 is a configuration diagram of the thermal printer according to the embodiment of the present invention.

In the figure, reference numerals 21A to 21C denote a motor control drive circuit, a motor, and a platen, respectively, which are one embodiment of the thermal paper moving means 11. Its function is the motor control drive circuit 21A
The motor 21B is driven by the
The thermal paper 16 inserted into the paper is moved and supplied.

Reference numeral 22 denotes a heating head control unit as an embodiment of the thermal head 12, which includes n heating resistors as an example of a plurality of heating elements R1 to Rn, and switching transistors Tr1 to Trn for selectively controlling the heating resistors. . The function of the heating head control unit 22 is to connect the heating resistors R1 to Rn connected to the power supply VP to the ground line 0V via the transistors Tr1 to Trn based on a plurality of heating element selection signals TR1 to TRn from the MPU 23. Is what you do. As a result, a drive current flows through the selected resistors R1 to Rn, and heat can be supplied to the thermal paper 16.

An MPU 23 is an example of the thermal head drive control means 13.
Signal input / output unit 23A, RAM 23B, arithmetic processing unit 23C, monitoring timer 23D, driving timer 23E, data recognition / confirmation unit 23F,
It consists of a clock generator 23G.

That is, the signal input / output unit 23A inputs and outputs the external control signal S0, the serial data Din, the plurality of heating element selection signals TR1 to TRn, the operation release signal (hereinafter referred to as a reset signal) RST, and the monitored signal TPR. is there. The RAM (register) 23B counts the number of execution processing routines simultaneously with the ordering of the printing processing routines. For example, the counting process counts the number of processing routines such as an input / output line level detection process, a heating element selection process, a runaway monitoring timer activation process, and a heating element drive timer activation process, and determines whether or not the program is executed. is there. The arithmetic processing unit 23C performs arithmetic processing of various data. For example, comparison processing is performed between a preset count and the number of processing routines, and a program is initialized and set according to the comparison result without shifting to printing processing.

Further, the monitoring timer 23D is an example of the first signal generating means 13A, and generates the first control signal S1 having the first pulse width φ1. This first control signal S1 is a runaway monitoring timer signal in the embodiment of the present invention. Further, the driving timer 23E is an example of the second signal generating means 13B, and generates the second control signal S2 having the second pulse width φ2. In the embodiment of the present invention, the second control signal S2 is a resistor driving timer signal. Based on this, a plurality of heating element selection signals TR1 to TRn are generated. Note that the pulse width φ1 of the runaway monitoring timer signal S1 is the resistor driving timer signal.
It is set longer than the pulse width φ2 of S2. In addition, the order of interruption of the monitoring timer 23D has priority over the order of interruption of the driving timer 23E.

Further, the data command / recognition / confirmation unit 23F is for confirming the level of the signal input / output by the signal input / output unit 23A, the normality / abnormality of the print control program, and instructing the supply of the monitored signal TPR. . The clock generator 23G generates a reference clock CLK. The monitored signal TPR according to the embodiment of the present invention is used when the MPU 23 executes the print control program based on the reference clock CLK, and is supplied by the data command / recognition / confirmation unit 23F.
This is output from the PU 23 to the reset circuit device 24.
This is a point different from the function of the conventional MPU.

Reference numeral 24 denotes a reset circuit device (reset IC with a watchdog function) as an embodiment of the monitoring means 14, which outputs a reset signal RST based on a monitored signal TPR generated when the MPU 23 executes the print control program. Things. For example, the monitored signal TPR is constantly monitored, and when the signal TPR becomes abnormal due to malfunction of an external circuit or runaway of a control system, a reset signal RST is output to initialize a print control program. (See FIG. 3 (b)).

Reference numeral 25 denotes a host CPU which is an example of the control means 15 and controls input and output of the motor control drive circuit 21A, the data buffer 26, and the MPU 23. For example, it outputs an external control signal S0 for starting a print processing main routine.

26 indicates a data buffer, 27 indicates a character pattern generation circuit, and 28 indicates an interface. The function is such that the data buffer 26 is operated based on the CPU 25 and the external input data DIN, whereby the serial data Din is supplied from the character pattern generation circuit 27 to the MPU 23.

Thus, according to the thermal printer according to the embodiment of the present invention, as shown in FIG. 2, the motor control drive circuit 21A, the motor 21B, the platen 21C, the plurality of heating resistors R1, R2,
A heating head control unit 22 composed of Ri and Rn, an MPU 23, a reset circuit device 24, a host CPU 25, a data buffer 26, a character pattern generation circuit 27, and the like are provided. The MPU 23 has a monitoring timer (hereinafter, referred to as a timer T1) 23D. A timer (hereinafter referred to as timer T2) 23E is provided.

For example, when performing printing processing on the thermal paper 16 that is moved and supplied by the motor control drive circuit 21A, the motor 21B, and the platen 21C, the MPU 23 is provided to the heating head control unit 22 including a plurality of heating resistors R1, R2, Ri, and Rn. From the second pulse width φ2
A heating element selection signal TRi based on the control signal S2 is output. At this time, the print control program of the MPU 23 is monitored by the reset circuit device 24.

That is, as shown in the monitoring operation time charts of FIGS. 3A and 3B, the reset circuit device 24 constantly monitors the monitored signal TPR generated when the MPU 23 executes the print control program. . For example, when the print control program is executed normally, the monitored signal TPR is regularly output from the MPU 23. Thus, the heating element selection signals TR1 to TRn are output to the respective heating resistors R1, R2, Ri, Rn (see FIG. 7A).

If the monitored signal TPR becomes abnormal due to malfunction of an external circuit or runaway of a control system, a reset signal RST for initializing a print control program is output to the reset circuit device 24.
Is output to the MPU23.

Therefore, the output processing of the heating element selection signals TR1 to TRn for controlling the timing of supplying heat to the thermal paper 16 is stopped (see FIG. 9B). As a result, all the heating elements R1, R
2. It becomes possible to turn off the drive current flowing through Ri and Rn. Note that the pulse width φ1 of the runaway monitoring timer signal S1 is longer than the pulse width φ2 of the resistor driving timer signal S2, and
The interrupt order of the timer T1 has priority over the interrupt order of the timer T2. For this reason, a normal reset operation can be prevented.

As a result, compared to the conventional printing time monitoring method, the heating resistors R1, R2,
Ri and Rn can be sufficiently protected.

Next, a print processing method of the thermal printer according to the embodiment of the present invention will be described while supplementing the operation of the printer.

FIG. 4 is a flowchart of the print processing method according to the embodiment of the present invention, and FIG. 5 is a flowchart of the processing for checking the program order.

For example, based on the serial data Din as shown in FIG.
In the case of the line dot printing system in which the thermal printing process is performed in a line shape in FIG. 16, first, in FIG. At this time, based on an external control signal S0 from the host CPU 25, M
The monitored signal TPR is transmitted from the MPU 23 to the reset circuit device 2 by the data command of the PU 23 and the supply instruction command of the recognition / confirmation unit 23F.
Output to 4.

Next, an initial setting process is performed in Step P2. This initial setting process sets the initial value of the print control program in the RAM 23B (register, etc.).

Next, in step P3, the data processing “Busy = L”
Reads serial data Din and performs processing. At this time,
The data buffer 26 is operated based on the CPU 25 and the external input data DIN.
Is supplied to the MPU 23.

Thereafter, in step P4, the input of the data Din is determined. At this time, if the input is completed (YES), step
At P6, the reading process is completed by the data process “Busy = H”. If the input is not completed (NO), an instruction to supply a TPR signal is issued in step P5.

Therefore, when the input is completed (YES), the reading process is completed by the data process “Busy = H” in step P6.

Further, in step P7, it is determined whether the input processing of the serial data Din is completed. At this time, if the input processing is completed (YES), the flow shifts to Step P8. If the input process has not been completed (NO), the process returns to step P3.

Therefore, if the input processing is completed (YES), the step
At P8, a TPR signal supply instruction is issued.

Thereafter, in step P9, a level check process for each signal line is performed. At this time, the data command / recognition / confirmation unit 23F confirms the level of the signal input / output by the signal input / output unit 23A as normal / abnormal based on the print control program.

Next, in step P10, a heating resistor R1, R2, Ri, Rn is selected. In this selection process, the heating resistors R1 to Rn for performing the thermal printing process on the thermal paper 16 in a line shape based on the serial data Din are selected.

Next, in step P11, a determination is made as to whether or not the same resistors R1, R2, Ri, Rn have been continuously selected. At this time, as shown in FIG. 3 (b), if the same resistors R1, R2, Ri, Rn are continuously selected (YES), the process proceeds to step P23 because it is abnormal. . If it is not selected continuously (NO), it is normal and step P12
Move to

Here, if the process has proceeded to Step P23 (YES), an initial setting process for each signal line is performed, the process proceeds to Step P24, an error is displayed on the host CPU 25, and the process proceeds to an infinite loop. At this time, since the monitored signal TPR to the reset circuit device 24 is selected when the same resistor Ri is continuously selected (abnormal), the "H" level is changed to the "L" level when the reset signal RST from the device 24 is normal. And the print control program is initialized. As a result, the driving is stopped without supplying the heating element selection signals TR1 to TRn without executing the printing process (see FIG. 3B).

When the same resistor Ri is not continuously selected (N
In O), since the operation is normal, the program order is confirmed in step P12. At this time, as shown in FIG.
In step P12A, the first of the signal line level check routines
Performs input processing of rank bits. Thus, the count 1 becomes RA
Written to M23B. Next, in step P12B, input processing of the second order bit of the heating element selection processing routine is performed. Thereby, the count 1 is written into the RAM 23B. Further, in step P12C, input processing of the third order bit of the startup processing routine of the runaway monitoring timer T1 is performed. Thus, the count 1
Is written to the RAM 23B. In step P12D, the input processing of the fourth order bit of the activation processing routine of the resistor driving timer T2 is performed. Thereby, the count 1 is written into the RAM 23B.

Thereafter, in step P12E, the input bit count is compared. At this time, if the input bit count is equal to the preset count = 4 (YES), the processing routine rank is normal, and the routine shifts to Step P13. On the other hand, if they are not equal (NO), the process routine order is abnormal, and the process proceeds to steps P23 and P24 to enter an infinite loop for stopping the printing process.

Therefore, when the count becomes equal to 4 (YES), the process returns to FIG. 4, and in step P13, the runaway monitoring timer 1 is started. At this time, the timer T1 sets the first pulse width φ
A runaway monitoring timer signal S1 is generated.

After that, in step P14, a startup process of the resistor driving timer T2 is performed. At this time, the timer T2 sets the second pulse width φ2
Generates a resistor driving timer signal S2. As a result, a plurality of heating element selection signals TR1 to TRn are generated based on the resistor driving timer signal S2, and a driving current flows through the selected heating resistance element Ri. Heat can be supplied.

 Next, in step P15, an instruction to supply a TPR signal is issued.

Next, in step P16, it is determined whether or not the operation of the resistor driving timer T2 has been completed. At this time, the timer
When the operation of T2 is not completed (NO), the process shifts to Step P17. When the processing is completed (YES), the flow shifts to step P18 to instruct the supply of the TPR signal.

Further, in step P17, a determination is made as to whether or not the operation of the runaway monitoring timer T1 has been completed. This judgment process
This is to confirm whether runaway monitoring is normally performed. This is because despite the operation of the resistor driving timer T2, the malfunction of the external circuit or the runaway of the control system stops the runaway monitoring timer T1 and the monitoring process cannot be continued. This is to prevent the situation.

That is, a process for confirming whether or not the signal TPR has stopped during the period in which the resistor driving timer T2 is operating. At this time, when the operation of the timer T1 is completed (YE
In S), since the printing control program execution is abnormal, the process shifts to steps P23 and P24 to shift to an infinite loop for stopping the printing process. If it does not end (NO), it means that the print control program has been executed normally, and step P1
Returning to step 5, an instruction to supply a TPR signal is issued.

Next, in step P19, a determination is made as to whether or not the operation of the runaway monitoring timer T1 has been completed. The determination process at this time is a termination confirmation because the interrupt order of both timers T1 and T2 is T1> T2.

That is, the timer T1 ends after the timer T2 ends. This is to forcibly stop the output of the timer T1 when the timer T2 ends, when there is a possibility that the runaway monitoring timer signal S1 may continue to be output due to the control runaway of the MPU 23 as shown in FIG. 3 (b). It is.

Therefore, if the operation of the timer T1 does not end (NO), the monitoring process is continuing, and the process returns to step P18 to return to TP
The instruction to supply the R signal is continued. If the processing has been completed (NO), the processing shifts to step P20, where the heating resistors R1 to R1
Perform normal termination processing for n.

Thereafter, as in the conventional example, the end of one-line printing is determined in step P21, and the end of the printing process is determined in step P22. In step P25, the control process is determined to be completed, and the printing process is completed.

Thus, the printing process can be performed on the thermal paper 16 while monitoring the printing control program of the MPU 23.

Thus, according to the print processing method according to the embodiment of the present invention, the heating elements R1, R2, Ri, Rn based on the print data Din while monitoring the print control program of the MPU 23.
Of the selection process.

For example, the monitoring process includes a level check confirmation process for each signal line in step P9, and the same resistors R1, R2, R in step P11.
Confirmation processing when i and Rn are continuously selected (abnormal), step P12
And the operation of the runaway monitoring timer T1 in step P19.

Therefore, when the number of processing routines, such as the input / output line level detection processing, the heating element selection processing, the runaway monitoring timer activation processing, and the heating element driving timer activation processing, does not reach or exceeds a preset count, Then, without going to the printing process, the process goes to Steps P23 and P24 to converge to an infinite processing loop for initialization setting. This makes it possible to monitor software runaway of the print control program caused by a malfunction of the external circuit.

This eliminates the need for the one-shot timer circuit 8B and the plurality of logical inversion output circuits NA1 to NAn used in the conventional print time monitoring method. From this, the heating element
The number of components for performing the print monitoring processing of R1 to Rn can be reduced, and the cost of the printer can be reduced.

〔The invention's effect〕

As described above, according to the thermal printer of the present invention, the thermal printer includes the thermal paper moving unit, the thermal head including a plurality of heating elements, the thermal head drive control unit, the signal monitoring unit, and the control unit. Monitors the monitored signal generated when the print control program is executed.

For this reason, when an error occurs due to a malfunction of an external circuit, a runaway of a control system, or the like, an operation release signal for initializing a print control program is output from the signal monitoring means to the thermal head drive control means. As a result, the output processing of the heating element selection signal itself for controlling the timing of supplying heat to the thermal paper is stopped, and the drive current flowing through all the heating elements can be cut off.

Further, according to the print processing method of the present invention, the heating element element is selected while monitoring the print control program of the thermal head drive control means.

Therefore, when the number of processing routines, such as the input / output line level detection processing, the heating element selection processing, the runaway monitoring timer activation processing, and the heating element driving timer activation processing, does not reach or exceeds a preset count, Then, the process is shifted to an infinite processing loop for performing initialization setting without shifting to the printing process. This makes it possible to monitor software runaway of the print control program caused by a malfunction of the external circuit.

As a result, compared to the conventional printing time monitoring method, the heating element can be sufficiently protected from malfunction of the external circuit and runaway of the control system, and the number of parts can be reduced, thereby reducing the cost of the printer. Can be achieved.

[Brief description of the drawings]

FIG. 1 is a principle diagram of a thermal printer according to the present invention, FIG. 2 is a configuration diagram of a thermal printer according to an embodiment of the present invention, and FIG. 3 is a monitoring operation of the thermal printer according to the embodiment of the present invention. FIG. 4 is a flowchart of a print processing method according to an embodiment of the present invention, FIG. 5 is a processing flowchart of program order confirmation according to an embodiment of the present invention, and FIG. FIG. 7 is a block diagram of a print processing monitoring circuit according to a conventional example, FIG. 8 is a flowchart of a print processing method according to a conventional example, and FIG. FIG. (Explanation of reference numerals) 11: thermal paper moving means 12, thermal head 13, thermal head drive control means 14, signal monitoring means 15, control means 13A first signal generation means .., 13B... Second signal generating means, R1 to R2... Heating element, TRi... Heating element selection signal, TPR... Monitored signal, RST... Operation release signal, S1. , S2... Second control signal, φ1, φ2... First and second pulse widths.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B41J 2/35-2/375

Claims (4)

(57) [Claims] A thermal paper moving means (11) for moving and supplying a thermal paper (16), and a thermal element comprising a plurality of heating elements (R1, R2, Ri, Rn) for printing on the thermal paper (16). Head (1
2) and thermal head drive control means (13) for outputting a heating element selection signal (TRi) to the thermal head (12)
A signal monitoring means (14) for monitoring a print control program of the thermal head drive control means (13); a thermal paper moving means (11); and a thermal head drive control means (1).
Control means (15) for controlling the input / output of 3), wherein the thermal head drive control means (13) counts each processing routine number of the print control program and executes the print control program A thermal printer for determining the quality of a printer. 2. A thermal printer according to claim 1, wherein said signal monitoring means initializes said print control program based on a monitored signal (TPR) from said thermal head drive control means. A thermal printer which outputs an operation release signal (RST). 3. A thermal paper moving means (11) for moving and supplying a thermal paper (16) and a thermal element comprising a plurality of heating elements (R1, R2, Ri, Rn) for printing on the thermal paper (16). Head (1
2) and thermal head drive control means (13) for outputting a heating element selection signal (TRi) to the thermal head (12)
A signal monitoring means (14) for monitoring a print control program of the thermal head drive control means (13); a thermal paper moving means (11); and a thermal head drive control means (1).
Control means (15) for controlling the input / output of 3), wherein the thermal head drive control means (13) includes a first pulse width (φ1) for monitoring runaway of the print control program.
A first signal generating means (13A) for generating the first control signal (S1), and a second control signal (S2) for generating a second pulse width (φ2) for generating the heating element selection signal (TRi). ) For generating the first control signal (S1), the pulse width (φ1) of the second control signal (S2) being greater than the pulse width (φ2) of the second control signal (S2). Wherein the priority of the first signal generation means (13A) is higher than the priority of the second signal generation means (13B). 4. A thermal paper moving means (11) for moving and supplying a thermal paper (16) and a thermal element comprising a plurality of heating elements (R1, R2, Ri, Rn) for printing on the thermal paper (16). Head (1
2) and thermal head drive control means (13) for outputting a heating element selection signal (TRi) to the thermal head (12)
A signal monitoring means (14) for monitoring a print control program of the thermal head drive control means (13); a thermal paper moving means (11); and a thermal head drive control means (1).
3) a control means (15) for controlling the input / output of the heating element (R1) based on the print data (Din) while monitoring the print control program of the thermal head drive control means (13). , R2, Ri, Rn), and performing a printing process on the thermal paper (16) based on the selection process.