JPH04257480A - Thermal printer - Google Patents

Abstract

PURPOSE:To check a capacity of a battery accurately by providing a mode in which all heating elements of a thermal head are driven to the thermal printer to be driven by the battery. CONSTITUTION:A frame (121) is photographically printed around a photographic printing pattern, and all heating elements of a thermal head (100) are made to be of a driven state in an E part. Thereby, a state in which a load on the battery becomes maximum is provided to check a capacity of the battery accurately.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention detects the capacity of the battery when all the heating elements of the thermal head are in a driving state in a battery-powered thermal printer, and the capacity of the battery drives the thermal head. Contains a circuit that issues a warning if there is a shortage.

0002

[Prior Art] In conventional battery-powered thermal printers, the battery capacity is detected by constantly monitoring the battery voltage during printing.After printing, the lowest value of the monitored voltages is selected and this value is set. It corresponds to the battery capacity.

FIGS. 6, 7, and 8 show a conventional method, in which (1) is a thermal head and (4) is thermal paper. (2) and (3) are heating elements, and a plurality of them are attached to one side of the thermal head (1). When the heating element a (2) is driven, the corresponding thermal paper develops color, and when the heating element b (3) is driven, the thermal paper corresponding to that part develops color. Similarly, by changing the drive pattern of the heating element attached to the thermal head, any desired pattern can be printed. FIG. 7 shows the results of printing a certain print pattern. At this time, the power supply battery A-A', B
FIG. 8 shows the monitored voltage between -B'. As the number of driven heating elements increases, the value by which the voltage decreases from the battery voltage V1 when not driven increases. When this print pattern is printed, the voltage value selected to determine the battery capacity will be the value indicated by V2.

0004

[Problems to be Solved by the Invention] However, in the above-mentioned conventional technology, the conditions for giving the voltage value that determines the battery capacity are not necessarily the same because the number of driving heating elements depends on the printed pattern. do not have. For this reason, battery capacity is not necessarily monitored correctly. In extreme cases, if a print pattern is printed that requires almost no heating element to be driven, a warning of insufficient battery capacity may not be issued even though the battery capacity is actually low. Thereafter, when a printing pattern that mostly drives the heating element is printed, printing unevenness occurs and a clear printing cannot be performed.

[0005]The present invention is intended to solve these problems, and its purpose is to detect battery voltage under the same conditions regardless of the printing pattern, and to correctly monitor battery capacity to prevent insufficient capacity. To provide a method for accurately issuing a warning, eliminating unevenness in printing, and obtaining a high-quality printed image.

[0006]

Means for Solving the Problems The present invention provides a thermal printer that uses a battery as a power source, by detecting the voltage of the battery when all the heating elements of the thermal head of the thermal printer are being driven. A thermal printer comprising means for monitoring the capacity of the battery, and means for issuing a warning when the battery capacity is insufficient to drive the thermal head.

[0007]

EXAMPLES The present invention will be explained in detail below based on examples.

FIG. 1 shows a block diagram of an embodiment of the present invention. For printing, print data is sent from the controller (110) to the head driver (104) through the data line (109). Also thermal head (100
) is controlled by a strobe signal (108) from a controller (110). (103) is a sensor for detecting the temperature of the thermal head, and temperature information is input to the controller through a temperature sensor voltage detection circuit (106). The motor (105) is also controlled by the controller. (107) is a power supply that supplies power to the entire system. (112) is a voltage detection circuit which detects the voltage of the power supply according to a command from the controller and sends the information to the controller.

FIG. 2 is a chart showing the flow of processing for printing, power supply capacity monitoring, and capacity shortage warning. The data for one line of the print pattern is sent to the head driver (104).
(113) and then the thermal head (100)
(114), and based on this information, the controller changes the pulse width to drive the thermal head, that is, the ON
After determining the time (115), perform printing (116)
. The controller determines whether all printing patterns have been printed (117), and if not, transfers the next data (117).
113), and in the case of termination, power supply voltage detection processing (118
). Based on the result of the process (118), the power supply capacity is checked (119). If the capacity is insufficient, a warning is issued (120). If not, the next process is performed.

FIG. 3 shows a printed pattern for detecting the power supply voltage under the same conditions, and is realized by printing a frame (121) around the printed pattern. FIG. 4 is a graph showing the results of monitoring the power supply voltage between C-C' and D-D' in FIG. This is the voltage when the When the E section is being printed, all the heating elements are being driven.

FIG. 5 shows an example of a warning of insufficient capacity that is displayed when the power supply capacity is insufficient, and (122) corresponds to the warning mark. Other warning methods such as sound and light can also be used.

0012

As described above, according to the present invention, by printing a frame around the print pattern and detecting the battery voltage at the part E in FIG. The battery capacity can be monitored, a warning of insufficient battery capacity can be issued accurately, and as a result, high-quality printed images without unevenness can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the present invention.

FIG. 2 is a diagram showing the flow of processing for printing, power supply voltage detection, and power supply capacity shortage warning according to the present invention.

FIG. 3 is a diagram showing a printed pattern used to detect power supply voltage under the same conditions.

FIG. 4 is a diagram showing the state of power supply voltage when printing the print pattern shown in FIG. 3;

FIG. 5 is a diagram of a capacity shortage warning mark that is printed when the power supply capacity is insufficient.

6, 7, and 8 are diagrams showing a conventional power supply voltage detection method.

[Explanation of symbols]

100 Thermal head 107 Power supply 110 Controller 112 Power supply voltage detection circuit 121 Print pattern frame 122　Lack of power supply capacity warning mark

Claims (1)

[Claims] Claims: 1. In a thermal printer using a battery as a power source, the capacity of the battery is monitored by detecting the voltage of the battery when all heating elements of a thermal head of the thermal printer are being driven. 1. A thermal printer characterized in that the thermal printer has means for generating a warning when battery capacity is insufficient to drive the thermal head.