JPH07290733A - Thermal printer - Google Patents

Abstract

PURPOSE:To display the printing distance of a thermal head at a proper time during the use of a thermal printer by counting the paper feed driving signal of a stepping motor to store the count value in a memory and operating the value stored in the memory on the basis of a running distance display command to display the operation result. CONSTITUTION:The paper feed driving signal of a stepping motor 107 is counted by a count means 101 and the value counted by the count means 101 is stored in a memory means 110. Further, the value stored in the memory means 110 is operated on the basis of a running distance display command by an operation means 101 and the operation result is displayed on a display means. That is, since the cumulated printing distance of a thermal head can be accurately confirmed, the standard of the replacing period of the thermal head is cleared and the thermal head can be displaced before it gets out of order.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a traveling distance detecting circuit in a thermal printer.

[0002]

2. Description of the Related Art Thermal printers for recording using thermal paper or transfer ribbons are widely used as recording devices.
The thermal printer uses a thermal head in which heating elements are arranged in a row as a recording head, and selectively energizes the heating elements of the thermal head to record a desired pattern. Further, in the thermal printer, the platen roller is provided at a position where it uniformly contacts the heating element of the thermal head, and a mechanism for pressing the thermal head to the platen roller is provided to apply a pressing pressure suitable for printing. Recording is performed by passing recording paper between the platen roller and the thermal head, and the paper is fed by rotating the platen roller. During printing or paper feeding, the recording paper is fed while being pressed against the heating element portion of the thermal head, so that the portion of the thermal head in contact with the paper is worn. Further, the heating element is deteriorated by the heat generated for recording. Therefore, the thermal head deteriorates as it prints and fails, so it must be replaced.

[0003]

However, when the printer is used, it is not known how far the thermal head has printed, so it was impossible to know whether the thermal head had reached the end of its life or failed. SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an apparatus capable of displaying the print distance of the thermal head at a proper time during use of the thermal printer.

[0004]

[Means for Solving the Problems] Counting means for counting a paper feed drive signal of a stepping motor, memory means for holding a value counted by the counting means, and memory means for holding a value of a traveling distance display command. A calculation means for calculating a value and a display means for displaying the calculation result are provided.

[0005]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of a control circuit in a thermal printer to which an embodiment of the present invention is applied. In FIG. 1, a communication unit 111 receives print data, a control command to execute paper feeding and test printing from a control device such as a personal computer, and outputs it to the control unit 101. Control unit 1
A communication unit 1 controls the entire device together with the communication control.
The print data input from the thermal head 109
Is output to. The control unit 101 includes a CPU 103 such as a microprocessor, a ROM 104 storing a control program for the CPU 103, and a RAM 113 used as a work area for the CPU 103.
In the backup RAM 110, internal data is held by the power of the backup battery 113 even when the power of the printer system is cut off. The print data output from the control unit 101 is energized by the head drive signal 112 to each heating element of the thermal head 109 and recorded on the thermal recording paper. The motor 107 is driven by a motor drive signal 102 output from the control unit 101 and conveys a recording sheet. Next, the running distance counting means will be described with reference to FIGS. FIG. 2 is a flowchart of the traveling distance count-up process in the control unit 101. First, in step S1, print data is received from the communication unit 111. In step S2, it is determined whether the received command is a test print command or another print command. If it is not a test print command in step S2, that is, if it is print data, the process proceeds to step 3 and in step 3, the number of paper feed steps is determined for the print data. After that, the process proceeds to step S4 and the motor drive signal 1
A motor drive signal pulse is output to 02. At the same time, the head drive signal is also output to the head drive signal 112. When the output is completed in step S4, the process proceeds to step S5. In step S5, the number of steps traveled is read / written.
S5 for backup RAM of mileage step number,
Details of the read / write in S6 will be described with reference to FIG. FIG. 3 is a flowchart of the processing performed inside the control unit 101. In step S10, the number of travel steps is read from the backup RAM 110 and the process proceeds to step S11. In step S11, step S10
The number of paper feeding steps is added to the number of traveling steps of, and the process proceeds to step S12. In step S12, the value added in step S11 is written in the backup RAM 110. With the above processing, the count-up processing of the control unit 101 ends. Next, a case where the test print command is received in step S2 will be described. When the test print command is received, the process proceeds to step S6 and the backup R is performed at step S12.
Read the number of running steps written in AM110,
Write to the RAM 105 of the control unit 101. Step S7
Then, the traveling distance is calculated from the number of traveling steps written in the RAM 110. For example, the paper feed motor 107 conveys the recording paper by 1 mm in 8 steps, and the backup RAM
Assuming that the number of travel steps of 110 is 3992 (decimal), 3992/8 steps = 499 (mm)
Is the mileage. The number of traveled distances calculated in step S7 is displayed in step S8, and the process ends. The display operation is performed by printing on an LCD such as a display device attached to the printer main body or a recording paper and outputting it. The gist of the present invention is to count the cumulative distance traveled by adding the number of steps to perform the printing operation to the value of the number of paper feed steps up to the present which exists in the backup RAM at the time of printing, and to run from this number of steps. It is to calculate and display the distance.

[0006]

According to the present invention, since the cumulative print distance of the thermal head can be accurately recognized, the time for replacing the thermal head can be known and can be replaced before the thermal head fails. Since the replacement time of the thermal head is known, the possibility of repairing after the failure is reduced, and the time during which the thermal printer cannot operate due to the failure can be reduced. Not only the thermal head but also the replacement time of the drive motor, the consumable parts of the drive system, etc. can be estimated according to this embodiment.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of a main part of a thermal printer of an embodiment.

FIG. 2 is a flowchart for switching a counting mechanism and a traveling distance display during a printing operation.

FIG. 3 is a flowchart showing details of read / write control for a backup RAM.

[Explanation of symbols]

 101 control unit 109 thermal head 110 backup RAM 111 communication unit

Claims (1)

[Claims] A counting means for counting a paper feed drive signal of a stepping motor, a memory means for holding a value counted by the counting means, and a calculation for calculating a value held in the memory means by a traveling distance display command. A thermal printer comprising means and display means for displaying the calculation result.