JPH03202363A - Thermal head protection system of thermal printer - Google Patents

Abstract

PURPOSE:To optimize the range in which printing is possible to protect a thermal head by providing a width sensor to recognize the width of paper inserted into a thermal printer and delivering, in response to the signals from the width sensor, the number of dots which can be printed and non-printing data in a part where there is no paper to a printing data output unit. CONSTITUTION:When a paper end sensor 1 detects that paper has been inserted, the state in which width sensors 2-1, 2-2 conduct detection shows that B5 paper has been inserted when both sensors are OFF, A4 paper has been inserted when the sensor 2-1 only is ON and B4 paper has been inserted when both sensors are ON. In a paper width detecting unit 3, when the width of paper is detected, the number of dots which can be printed corresponding to the width of each paper is set in a work area. A printing data output unit 4 transfers set number of dots which can be printed and non-printing data in a part where there is no paper to a printing control unit 5.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for protecting a thermal head for printing in a thermal printer.

[Conventional technology]

Conventional thermal printers protect the line thermal head by setting the print limit positions on the left and right sides in advance according to the paper width used by the user.

[Problem to be solved by the invention]

In the conventional thermal printers mentioned above, there is no mechanism to check the validity of the print limit position set by the user, so if the setting is incorrect or not set, the platen will print out when there is no paper. Because the ink is transferred to the platen, the ink adheres to the platen, making it impossible to maintain the smoothness of the platen, and the thermal head may be destroyed.

Furthermore, because the printed characters are not printed on the paper and come off the paper,
It has the disadvantage of missing characters.

[Means to solve the problem]

The present invention includes a width sensor that recognizes the paper width of paper inserted into a thermal printer, and a paper width sensor that receives this signal and sends the number of printable dots and non-print data for areas without paper to a print data output unit. It consists of:

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram of a thermal head protection system compatible with three types of paper widths in one embodiment of the present invention.

This embodiment includes a vapor end sensor 1 for detecting the presence or absence of paper inserted into a thermal printer, a width sensor 2-1 and a width sensor 2-2 for recognizing the width of the inserted paper, and a width sensor. 2-1 and width sensor 2-2
Paper width detection unit for processing input signals from 3. It is comprised of a print data output section 4 that creates print data corresponding to the paper width and transfers it to a print mechanism control section 5.

In this embodiment, the paper is always guided so that the left edge is at a fixed position in the direction of the line thermal head, and the paper that can be used is 85th edition.

When A4 size and 84 size paper are used, the width sensor 2-1 is installed at a position to detect the right edge of the A4 size paper, and the position sensor 2-2 is installed at a position to detect the right edge of the B4 size paper. When vapor end sensor 1 detects that paper has been inserted, depending on the detection status of width sensors 2-1 and 2-2, when both sensors are OFF, when only B5 paper 1 width sensor 2-1 is ON indicates that A4 paper has been inserted, and when both sensors are ON, it indicates that B4 paper has been inserted. This paper width determination process is
This is performed by the paper width detection section 3.

When the paper width detection section 3 detects the paper width, it sets the number of printable dots corresponding to each paper width in the work area. The print data output section 4 sends the following information to the print control section 5.
Transfers the set number of printable dots and non-print data for areas with no paper. These operations can prevent printing on areas where there is no paper, and can protect the thermal head.

〔Effect of the invention〕

As explained above, the present invention has the advantage that the printable range can be optimally determined and the thermal head can be protected using the number of printable dots set by the width sensor as a parameter.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. 1... Vapor end sensor 2-1... Width sensor -, 2-2... Width sensor -, 3... Paper width detection section, 4... Print data output section, 5... - Printing mechanism control unit.

Claims (1)

[Claims] It includes a width sensor that recognizes the paper width of the paper inserted into the thermal printer, and a paper width detection unit that receives this signal and sends the number of printable dots and non-printing data for areas without paper to the print data output unit. A protection method for a thermal head of a thermal printer, which is characterized by: