JPH04345860A - Controller for thermal printer - Google Patents

Abstract

PURPOSE:To make smooth the use frequency distribution of heating dots and to prolong the service life thereof by a constitution wherein the use range of the heating dot is shifted every time when the driving time of thermal printer or paper feed amount reaches a predetermined level. CONSTITUTION:Print control section 10 in a POS(point of sale controller)/ECR (electronic cash register), for example, receives data from the control section in the body and delivers an ON/OFF signal for each heating dot(comprising heating element R1-Rn) to a head drive circuit 12 with a predetermined timing with reference to a character generator 11. Furthermore, it delivers a paper feed control signal to a motor drive circuit 14. Conducting times of each heating dot for every print of receipt and the number of print lines are then counted. Printing area on the receipt is then shifted by single character to the right or left for every ten thousand lines, for example, according to the number of conduction of each heating dot.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal printer control device, and more particularly to a thermal printer control device that substantially extends the life of a thermal head.

0002

[Prior Art] Traditionally, POS (point of sale)/
Serial dot matrix printers are used in devices such as ECRs (electronic cash registers) that register sales details and payment/receipt details. Nowadays, so-called line dot type thermal printers, which can print at high speed and with low noise, are being installed. However, line dot type thermal printers generally have a shorter lifespan than serial dot matrix type printers. When a thermal head is used for a long period of time, one or more of the many heat generating dots arranged in a line becomes defective, and a linear non-printing area is formed in the direction of paper movement. Since healthy heat-generating dots print normally, there is a risk that the occurrence of defective dots may be overlooked depending on the location where the linear non-printing area occurs. Conventionally, the number of printed lines is counted, and when the number of lines reaches approximately 95% of the number of lines predetermined as the lifespan of the thermal head, the operator is notified that it is time for maintenance.

0003

[Problems to be Solved by the Invention] However, serial dot matrix printers have a problem with M
Compared to a CBF of 3 million to 5 million lines, the head life of a thermal printer is 3×107 to 5×
It is as short as 107 pulses (1.1 million to 3 million lines when converted to the number of lines of characters printed on POS/ECR journal paper and receipt paper), and maintenance must be requested every relatively short period of time. Furthermore, when performing maintenance and inspection on devices such as POS/ECR, it is necessary to replace the entire thermal printer with an alternative thermal printer and request the printer manufacturer to repair the removed thermal printer.

An object of the present invention is to provide a thermal printer control device that can extend the life of a thermal printer head to a level comparable to that of a serial dot matrix type printer, by devising the control of the thermal printer. It's about doing.

[0005]

[Means for Solving the Problems] The life of a thermal head is approximately determined by the number of times electricity is applied to each heating dot.

[0006] However, depending on the printing content of a thermal printer, the plurality of heat-generating dots configured in the head may not be used uniformly, and generally there is a certain distribution in the frequency of use of each heat-generating dot. arise. Therefore, there is a high probability that the most frequently used heat generating dot will be defective, and the lifespan of that heat generating dot determines the lifespan of the thermal head, that is, the interval between maintenance requests for the entire thermal printer.

The present invention was made by paying attention to the above-mentioned phenomenon, and includes a thermal printer in which a thermal head for simultaneously printing one line is arranged orthogonally to the direction of paper movement, and a thermal printer formed in the thermal head. a heating dot selection driving means for driving a heating dot usage range of a certain width among the heating dots based on print data; The heating dot use range shifting means shifts the position of the heating dot.

[0008]

[Operation] In the thermal printer control device of the present invention, the thermal head of the thermal printer is arranged perpendicular to the paper moving direction, and the heating dot selection driving means is formed on the thermal head based on print data. Printing is performed using heat-generating dots with a fixed width among the heat-generating dots. The heating dot usage range shifting means shifts the position of the heating dot usage range every time the driving time of the thermal printer or the paper feed amount reaches a constant value. In this way, during continuous use of the thermal printer, each time the thermal printer drive time or paper feed amount reaches a certain value, the number of heat-generating dots actually used among the heat-generating dots formed on the thermal head increases. Since the usage range moves to the entire area, the cumulative number of times each heating dot is energized is averaged,
The usage frequency distribution is smoothed. Therefore, for example, only one heating dot is not used more frequently, and the usage time until the heating dot reaches the number of times of energization set as the lifespan is extended. Therefore, the printer manufacturer's preset head life (
It is also possible to lengthen the interval between maintenance requests by extending the set life at a fixed premium rate relative to the number of printing lines.

[0009]

Embodiment FIG. 1 shows the configuration of a POS/ECR which is an embodiment of the present invention. In this way, the POS/ECR consists of a control section 1 that performs overall control, a storage section 2, a keyboard 3, and a display section 4.
and a printer section 5. In the control unit 1, a program for making this device function as a POS terminal and a cash register is written in the ROM in advance. The CPU executes the program and, for example, controls the printer unit 5 to instruct printing of receipts and journals, and also performs control for monitoring the lifespan of the printer, which will be described later. The storage unit 2 is comprised of a recording device such as a semiconductor memory or a floppy disk device, and stores various data for printer monitoring. The keyboard 3 is used to change the mode of the device and to set head life settings and the like. For example, the display unit 4 displays a message to that effect when a request for maintenance of the printer becomes necessary.

Next, FIG. 2 shows the configuration of the printer section 5 shown in FIG. 1. In FIG. 2, the print control unit 10 receives print data from the control unit of the main body, refers to the character generator 11, and outputs an on/off signal for each heating dot to the head drive circuit 12 at a constant timing,
It also outputs a paper feed control signal to the motor drive circuit 14. The head drive circuit 12 is a thermal head 13
The heating resistors R1 to Rn constituting each heating dot are selectively energized. The motor drive circuit 14 supplies a driving current to the stepping motor 15 to feed the paper.

Next, the heating dot usage range shift control performed by the control section 1 shown in FIG. 1 will be explained based on FIG. 7. The printer section includes a receipt printing section and a journal printing section.
Printing is controlled individually for each. For example, in the case of a receipt, the maximum printing area of the receipt is an area slightly narrower than the paper width, and characters and the like can be printed anywhere within this area. However, in this example, the maximum printing area of the receipt is divided into characters (digits).
Print characters, etc. in one of the sections. When installing a new thermal printer and starting to use it, use the "receipt printing area at the time of installation" shown in the figure. At this time, the two characters at both ends of the maximum printing area of the receipt are not used. Thereafter, the number of times each heating dot is energized and the number of printed lines are counted each time a receipt is printed. And every 10,000 lines (
Every 10,000 pulses to the stepping motor), the receipt printing area is shifted by one character to the right or left according to the number of times each heating dot has been energized (hereinafter, this process is referred to as energization number averaging process). Specifically, when 10,000 lines have been printed, the maximum value of the heat-generating dots in each section is taken as the representative value for that section, and the maximum value among the representative values for each section is taken as the head life monitoring value. Furthermore, the representative values of the sections adjacent on both sides of the section having the maximum number of times of energization are compared, and the receipt printing area is shifted by one character toward the section with the smaller representative value. Therefore, for the subsequent 10,000 lines of printing, only the heating dots in that receipt printing area are used. Recipe in Figure 7
In the example of paperback printing, since L<R, the receipt printing area is shifted to the left by one character by the energization frequency averaging process. After that, when 10,000 lines are printed again, the printing area is similarly shifted to the right or left by one character based on the number of times each heating dot has been energized up to that point, but the maximum of the representative values for each section is The representative values of the sections adjacent to the left and right of the section with the value are compared, but if there is no empty printing area for one character in the direction of the section with the small representative value, further shifts cannot be performed, so only in that case. Shift the print area by one character in the opposite direction (toward the section with the largest representative value). The above example was about receipt printing, but the same applies to journal printing. In the journal printing example shown in the same figure, since L>R, the journal printing area is moved one character to the right by the energization frequency averaging process. Shifted.

In this way, by distributing the part of the receipt/journal with the maximum printing frequency into sections of two or three characters, the number of times each heating dot is energized is averaged, thereby lowering the head life monitoring value. This can substantially extend the life of the head. Note that if the division is made into half a character, the probability that the number of times of energization of each heating dot will be averaged increases.

Next, FIG. 3 shows the structure of various data stored in the storage section 2 shown in FIG. 1. In Figure 3, area M
1 stores the number of times of energization of each heating dot since the current thermal head started being used. Areas M2 and M3 respectively store data representing which range of the maximum print area is to be the print area for receipts and journals. Areas M4 and M5 store the representative value of each section when the number of times of energization of each heating dot is divided into sections for receipts and journals, respectively. Area M6 stores head life values specified by the printer manufacturer in terms of the number of print lines. Area M
In 7, a head life setting value set for determining the timing of a maintenance request is stored. When the head life span is extended as will be described later, this head life setting value is greater than the head life value of M6. Area M8 stores the head life monitoring value, which is the maximum representative value of each section in the energization frequency averaging process. Area M9 stores a maintenance request flag indicating whether or not a maintenance request is necessary. In area M10, the number of times of energization of each heating dot at the time when a maintenance request becomes necessary is stored for each dot. Area M11 stores the cumulative number of print lines since the current thermal head started being used. Area M12 stores the cumulative number of printed lines at the time when a maintenance request is required.

4 to 6 are flowcharts showing the processing procedure of the control section 1 which controls the printer section 5 using the various data shown in FIG. 3.

FIG. 4 shows a processing procedure during installation of the POS/ECR. First, various setting processing during installation similar to that of a normal POS/ECR is performed (n1), and a head life value is selected and set. For normal settings, set the head life setting value by subtracting 10,000 pulses from the head life value specified by the printer manufacturer (n2 → n3).
. In the case of extended settings, set the head life setting value as the value obtained by multiplying the head life value by a certain extra multiplier A (for example, 1.05 to 1.5) and subtracting 10,000 pulses (n2 → n4 ).

FIG. 5 shows the procedure of daily processing from daily registration to payment. First, normal registration processing is performed in registration mode (n10). Then, the number of times of energization of each heating dot is accumulated for each dot, and the number of printing lines is accumulated (n1
1→n12). Thereafter, it is determined whether or not among the number of times of energization of each dot up to now, there is one that has reached the value set as the head life setting value (n13). If there is even one heating dot that has been energized for a number of times that exceeds the head life setting value, a maintenance request flag is set, and the number of times that each dot is energized and the number of printed lines at that point are recorded in the data at the time of the maintenance request (see Figure 3). (see M10, M12) (n13→n14
→n15). In the payment mode, first, normal payment processing is performed (n16→n17). After that, if the maintenance request flag is not set and the status is normal, all heat-generating dots of the thermal head are energized and printing is performed (n18→n1
9). After that, if there is an input from the operator indicating that a missing dot, that is, a defective heat-generating dot has been detected through this printing, a maintenance request flag is set, and the number of times each heat-generating dot is energized and the number of printing lines are set for each time the maintenance request is made. The number of dot energizations and the number of printing lines at the time of maintenance request are stored respectively (n20→n21→n22). Then, a message indicating that a maintenance request is necessary is displayed on the screen (n23). If there is an instruction from the operator indicating that there are no missing dots through test printing by energizing all dots, then it is determined whether or not it is time to average the number of energizations every 10,000 pulses. If so, perform energization frequency averaging processing. In other words, as described using FIG. 7, the section with the maximum number of times of energization is detected, and the print area data (see FIG. (Refer to areas M2 and M3 in Section 3).
n20→n24→n25).

FIG. 6 shows the processing procedure at the time of maintenance inspection. First, when replacing the thermal printer, the number of times each dot is energized at the time of the maintenance request and the number of print lines at the time of the maintenance request (M10 and M12 in FIG. ) to print (n30
→n31). Subsequently, the number of energizations for each dot and the number of printing lines (M1 and M11 in FIG. 3) are initialized to 0, and the maintenance request flag is reset (n32→n33). After that, the service person turns off the power to the device and replaces the thermal printer (n34). If you want to change the lifespan value after turning on the power again, enter the setting value (
n35→n36). At this time, a new lifespan value is determined based on the data of the number of times each dot is energized at the time of the maintenance request and the number of printed lines at the time of the maintenance request, using this as the actual result.

According to the embodiment described above, the shift direction of the printing area is optimized for each fixed period of use of the thermal printer, so the number of times of energization of each heating dot is efficiently averaged, and the thermal head is Lifespan can be substantially extended. Furthermore, if the consent of the POS/ECR user is obtained, the head life value (the current limit value per dot) can be extended to lengthen the replacement period of the thermal printer. Furthermore, when requesting maintenance, you can be informed of the number of times each dot is energized and the number of printed lines.
It is also possible to request printer manufacturers to guarantee head life according to these performance data.

[0019]

[Effects of the Invention] According to the present invention, the frequency of use of the plurality of heat-generating dots formed on the thermal head is averaged, and each heat-generating dot is distributed evenly without using only a particular heat-generating dot frequently. It can be used for Therefore, the usage time until defective dots actually occur (
The number of printing lines) can be extended, and the maintenance intervals can also be extended.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of a POS/ECR according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of the printer section 5 in FIG. 1.

FIG. 3 is a partial configuration diagram of the inside of the storage unit 2 in FIG. 1.

FIG. 4 is a flowchart showing the processing procedure of the control unit 1 in FIG. 1 when installing the POS/ECR.

FIG. 5 is a flowchart showing the routine processing procedure of the control unit.

FIG. 6 is a flowchart showing a procedure for processing inspection values by the control unit.

FIG. 7 is an explanatory diagram of energization frequency averaging processing.

Claims (1)

[Claims] Claims: 1. A thermal printer in which a thermal head for simultaneously printing one line is arranged perpendicular to the moving direction of paper, and print data that defines a heating dot usage range of a certain width among the heating dots formed on the thermal head. A thermal dot selection drive means that drives based on the thermal dot selection drive means, and a heat generation dot use range shifting means that shifts the position of the heat generation dot use range every time the driving time of the thermal printer or the paper feed amount reaches a certain value. Printer control device.