JP2001030530A - Thermal printer and print density regulating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermal printer ensuring an optimal print quality constantly by regulating the density automatically to a correct level even when a thermal sheet having different properties is employed. SOLUTION: A print density storing section 6 comprises a rewritable nonvolatile memory and a trial print section 8 is provided at a print control section 7. The trial print section 8 performs trial printing while varying the print density level, step by step, from the light side toward the dark side. When nonpresence of a thermal sheet 5 is detected by detecting a trial printed part through a paper end sensor 4, print density level at the time of detection is written in the print density storing section of a thermal printer 10. According to the arrangement, print density is regulated automatically to a correct level by simply setting a thermal sheet and printing is performed constantly with a correct print density even if thermal sheets having different properties are used alternately.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal printer, and more particularly, to a method for automatically adjusting print density in accordance with the characteristics of thermal paper and a method for adjusting the same.

[0002]

2. Description of the Related Art Heretofore, the print density of a thermal printer has been adjusted according to the thermal paper specified by the manufacturer, and there is no need to adjust the print density as long as the thermal paper specified by the manufacturer is used. However, when using multiple thermal printers from different manufacturers, there is a demand to unify the thermal paper into one type regardless of the thermal printer manufacturer. However, since the characteristics of thermal paper differ depending on the type, they are unified into one type. I could not do it, and I had to prepare several kinds of thermal papers for the thermal printer. Therefore, a thermal printer provided with a print density knob and capable of manually adjusting the print density has been put to practical use. However, even if the thermal paper is adjusted once, if the thermal paper is replaced with another paper of a different characteristic, a test print must be performed again, and the manual adjustment must be performed while checking with the eyes. Or, if this adjustment is neglected, there is a problem that the print quality is deteriorated.

[0003]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and automatically adjusts the density to an appropriate level even when thermal papers having different characteristics are used. It is intended to provide a printer.

[0004]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a thermal head in which a plurality of heating elements are arranged, a roller disposed opposite to the thermal head, and a roller disposed between the thermal head and the roller. A paper feeding mechanism that feeds thermal paper, a paper end sensor that detects the presence or absence of thermal paper based on the intensity of light, and a print density storage unit that stores a voltage applied to the heating element of the thermal head as a print density level. ,
A print control unit that controls each of the units, and enables printing when the paper end sensor detects the presence of the thermal paper, and the print control unit controls and stores each of the heating elements in the print density storage unit. By applying a predetermined voltage based on the print density level to generate heat, the thermal paper is colored,
In the thermal printer in which printing is performed and the thermal paper is fed, and when the paper end sensor detects the absence of the thermal paper, the printing is stopped and the out-of-paper is notified by a lamp or a buzzer. In addition to a rewritable nonvolatile memory, the print control unit is provided with a test print unit, and the test print unit changes the print density level from a light side to a dark side by one step and performs test print. The thermal printer is configured such that, when the paper end sensor detects the portion where the test printing is performed and the absence of the thermal paper is detected, the print density level at the time of the detection is stored in the print density storage unit.

When the thermal printing paper is detected by the paper end sensor, the trial printing section feeds the thermal paper in a positive direction for a predetermined length, and then performs a full black trial printing at the lightest density. After a certain length, the printed portion of the thermal paper is sent to the paper end sensor in the reverse direction, and if the paper end sensor does not detect the absence of paper, the print density is insufficient and the thermal paper is again fixed. Then, after increasing the density level by one step and performing a test print of all black for a certain length, the print portion of the thermosensitive paper is fed in the reverse direction to the position of the paper end sensor, and When the paper end sensor detects the absence of paper, the print density level at that time is controlled to be stored in the print density storage section, and the subsequent normal printing is performed by the print control section at the same print density level. Thermal It is the print density adjustment method of the printer.

[0006] A thermal printer is provided in which the detection density of the paper end sensor is adjustable or is adjusted in advance.

The paper end sensor is a thermal printer comprising a light emitting element and a light receiving element, and a reflection type paper end sensor for receiving the light emitted from the light emitting element and reflected by the thermal paper with the light receiving element.

[0008]

As described above, in the thermal printer according to the present invention, the print density storage section is composed of a rewritable nonvolatile memory, and the print control section is provided with a test print section. The printing unit changes the print density level from light to dark one step at a time and performs test printing. Since the thermal printer is designed to store the level in the print density storage section, just by setting the thermal paper, it is automatically adjusted to the appropriate print density, even if the thermal paper with different characteristics is used alternately. It is possible to always print at an appropriate print density.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A thermal printer according to the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic configuration diagram of a thermal printer according to the present invention. As shown in the figure,
The thermal printer 10 includes a thermal head 1 in which a plurality of heating elements are arranged, a roller 2 opposed to the thermal head 1, and a roller 2 between the thermal head 1 and the roller 2.
A paper feeding mechanism 3 for feeding the thermal paper 5; and a paper end sensor 4 for reflecting light from the light emitting element 4a on the thermal paper and receiving the light with the light receiving element 4b and detecting the presence or absence of the thermal paper 5 based on the intensity of the light.
A print density storage section 6 for storing a voltage applied to the heating element of the thermal head 1 as a print density level, a print control section 7 for controlling the above sections, and a test print control section 8 for controlling test printing. Have. The light receiving sensitivity of the paper end sensor 4 is adjusted in advance by the adjusting means 4c.

Next, the operation of the above configuration will be described. FIG. 2 is an operation flowchart showing an embodiment of a print density adjusting method for a thermal printer according to the present invention.
When the power of the thermal printer 10 is turned on, predetermined initial settings are performed, and the paper end sensor 4 detects the presence or absence of the thermal paper 5. If the thermal paper 5 is present, the print density storage unit 6 has already been used.
The printing control unit 7 performs printing based on the print density level stored in the printer. For example, when the paper end sensor 4 detects the absence of the thermal paper 5 and subsequently detects the presence of the thermal paper 5, it is determined that the thermal paper 5 has been replaced, and the test print control unit 8 sets the test print control unit 8 shown in FIG. Perform printing operation. When the paper end sensor 4 detects the absence of the thermal paper 5, the mounting of the thermal paper 5 is monitored (STP1), and when the thermal paper 5 is confirmed, the thermal paper 5 is sent in a fixed length forward direction (STP2). Next, the lightest print density level is set in the print density storage unit 6 (STP3), and all black is printed for a fixed length (STP4). Next, the thermal paper 5 is fed in the reverse direction (STP5), and the presence or absence of the thermal paper 5 is detected by the paper end sensor 4 in the all black print portion (STP6). S
If the paper end sensor 4 does not detect the absence of the thermal paper 5 in TP6, the print density level is increased by one step and set in the print density storage unit 6 (STP7), and all black is printed again for a fixed length (STP4). I do. The thermal paper 5 is fed again in the reverse direction (STP5), and the presence or absence of the thermal paper 5 is detected by the paper end sensor 4 in the all black print portion (STP6). If the paper end sensor 4 detects the absence of the thermal paper 5 in STP6, the print density level set at that time is stored in the print density storage unit 6.
And the test printing is completed.

[0011]

As described above, according to the thermal printer of the present invention, when the paper end sensor detects that the thermal paper has been fed, the print controller corrects the thermal paper by a predetermined length. After performing a fixed length test print of all black with the lightest density, control the print portion of the thermosensitive paper to the paper end sensor position in the opposite direction, and then control the paper end sensor. If the printer does not detect the absence of paper, the print density is determined to be insufficient and the thermal paper is fed again in the positive direction for a certain length, and then the density level is raised by one step and a test print of all black is performed for a certain length. When the paper end sensor detects that there is no paper, it controls so that the printed part of the thermosensitive paper is sent in the opposite direction to the position of the paper end sensor.
The density level at that time is stored in the print density storage unit,
After that, printing is performed at the same density level, so the sensor that detects the printing density can also be used as a paper end sensor that detects the presence or absence of paper, and just by setting the thermal paper, the appropriate printing is automatically performed Even if thermal papers having different densities and adjusted in density are used alternately, printing can always be performed with an appropriate print density.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a thermal printer according to the present invention.

FIG. 2 is an operation flowchart showing one embodiment of a thermal printer according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Thermal head 2 Roller 3 Paper feed mechanism 4 Paper end sensor 4a Light emitting element 4b Light receiving element 4c Adjusting means 5 Thermal paper 6 Print density storage section 7 Print control section 8 Trial print control section

Claims (4)

[Claims] 1. A thermal head in which a plurality of heating elements are arranged; a roller disposed to face the thermal head; a paper feeding mechanism for feeding thermal paper between the thermal head and the roller; A paper end sensor for detecting the presence or absence of thermal paper, a print density storage section for storing a voltage applied to a heating element of the thermal head as a print density level, and a print control section for controlling the respective sections. When the end sensor detects the presence of the thermal paper, printing is enabled, and the printing control unit controls and applies a predetermined voltage to each of the heating elements based on the printing density level stored in the printing density storage unit. The heat-sensitive paper is colored by heating, and the heat-sensitive paper is printed and the heat-sensitive paper is fed. When the paper end sensor detects the absence of the heat-sensitive paper, the printing is stopped and the running out of paper is stopped. In the thermal printer, which is notified by a lamp or a buzzer, the print density storage unit is configured by a rewritable nonvolatile memory, and the print control unit is provided with a test print unit, and the test print unit is configured to print the print data. When the density level is changed stepwise from the light side to the dark side by one step, test printing is performed, and the portion where the test printing is performed is detected by the paper end sensor to detect the absence of the thermal paper, and the printing density level at the time of the detection is determined by the printing density. A thermal printer characterized in that it is stored in a storage unit. 2. The test printing section, when detecting that the thermal paper has been loaded by the paper end sensor, feeds the thermal paper in a positive direction for a fixed length, and then tests all black at the lightest density. After printing for a certain length, feed the printed portion of the thermal paper in the opposite direction to the paper end sensor,
If the paper end sensor does not detect the absence of paper, the print density is determined to be insufficient and the thermal paper is fed again in the positive direction for a certain length, and then the density level is raised by one step to perform a test print of all black for a certain length. After that, the printed portion of the thermal paper is sent in the reverse direction to the position of the paper end sensor, and when the paper end sensor detects the absence of paper, the print density level at the time of the detection is stored in the print density storage unit. 2. A print density adjusting method for a thermal printer according to claim 1, wherein the print control section controls the print density so as to perform the subsequent normal printing at the same print density level. 3. The detection density of the paper end sensor,
2. The thermal printer according to claim 1, wherein the thermal printer is adjustable or pre-adjusted. 4. A paper end sensor comprising a light emitting element and a light receiving element, wherein the light receiving element receives light emitted from the light emitting element and reflected on the thermal paper by a light receiving element. The thermal printer according to claim 1, wherein