JP3078367B2 - Thermal printer controller - Google Patents

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 for performing printing by energizing a thermal head based on print data.

[0002]

2. Description of the Related Art In general, a thermal printer comprises a thermal printer mechanism having a paper feed mechanism for printing paper and a thermal head, and a control section for driving and controlling the paper feed mechanism and the thermal head based on print data.

When a thermal printer is provided in an electronic device as a print output device, a thermal printer controller is designed in accordance with various characteristics of a thermal printer mechanism used. However, the resistance value of each heating element of the thermal head provided in the thermal printer mechanism has a certain degree of variation depending on conditions at the time of manufacturing the thermal head. In a conventional thermal printer mechanism, the average resistance value of each heating element of a built-in thermal head is measured in advance, and is divided into several ranks. For example, in the case of a thermal head having a heating element having a standard resistance value of 120Ω, the resistance value is divided into three ranks of 126 to 138Ω as rank A, 114 to 126Ω as rank B, and 102 to 114Ω as rank C. Is attached with a label indicating the ranking. Therefore, when such a thermal printer mechanism is incorporated in an electronic device and used, the energizing time of the thermal head suitable for the rank is controlled.

[0004]

However, in the above-described conventional thermal printer control device, the display of the resistance value rank of the thermal head provided in the thermal printer mechanism used is used to set the rank of the thermal printer by using a dip switch or the like. The switch must be operated, which not only complicates the work, but also has the problem that the printing quality is significantly impaired by incorrect settings. Also, since the resistance value of the thermal head generally changes over time, even if the resistance value rank displayed on the thermal printer mechanism is set correctly, the print quality deteriorates as the thermal printer is used. There were also problems.

[0005] The resistance value rank displayed on the conventional thermal printer mechanism is an average value of the resistance values of the respective heating elements constituting the thermal head, such as the resistance value of each heating element and its variation. And it was only possible to control the conduction time according to the resistance value rank.

It is an object of the present invention to construct a thermal head.
An object of the present invention is to provide a thermal printer control device capable of grasping the resistance value of each heating element .

Another object of the present invention is to provide a thermal head.
To automatically set the resistance rank of the
Eliminates the complexity of network settings and eliminates problems caused by incorrect settings.
And prevent the effects of thermal head aging.
Another object of the present invention is to provide a thermal printer control device.

[0008]

SUMMARY OF THE INVENTION A thermal printer control device according to the present invention includes a register for inputting print data for each heating element of a thermal head, and a heating element to be energized in accordance with the state of each bit output of the register. In a thermal printer control device equipped with a heating element drive circuit that selectively drives the body , it is assumed that each heating element of the thermal head is individually energized.
In addition, resistance value measuring means for measuring the resistance value of each heating element,
The measured resistance value of each heating element is used as print data as described above.
And resistance value printing control means for sequentially giving the resistance value to the register.

Further , the resistance value is measured by the resistance value measuring means.
Of calculating the representative resistance value of the heating element from the resistance value of each heating element
A table resistance value calculating unit, and the heat generation based on the representative resistance value.
Energization time control means for controlling the energization time of the drive circuit;
Provided, the resistance value measuring means applies a smaller energy than the energy applied to the heating element during printing to measure the resistance of each heating element.

[0010]

In the thermal printer control device according to the present invention, the resistance value measuring means individually energizes each of the heating elements of the thermal head, measures the resistance value of each of the heating elements, and prints the resistance value mark.
The character control means prints the measured resistance value of each heating element
Sequentially to the register for printing. This allows
The resistance value of each heating element is sequentially printed out. This function is supported.
Can be used for maintenance of printers.
From the printing result,
Easily ascertain good / bad condition of heat bodies or signs of failure
can do.

Further, a representative resistance value is obtained from the resistance value of each heating element measured by the resistance value measuring means, and the energizing time of the heating element drive circuit is controlled based on the representative resistance value. Of each heating element
When measuring the resistance value, it is applied to the heating element during printing
An energy smaller than the energy is applied. like this
The thermal printer connected to the thermal printer controller.
The actual resistance of each head is measured and its representative resistance is
Control is performed according to the
The setting operation of the resistance rank setting switch becomes unnecessary,
The problem caused by erroneous setting is also solved. The resistance of each heating element
The energy applied to the heating element during printing when measuring the resistance value
Since the smaller energy is applied,
The printing paper does not develop heat, and wastes paper.
Not even. Further, the resistance value is measured every time the power is turned on.
The resistance of the thermal head over time.
It can automatically follow a value change.

[0012]

FIG. 1 is a circuit diagram showing a configuration of a thermal printer control device according to an embodiment of the present invention. In FIG. 1, a CPU 1 includes a ROM, a RAM, and an A / D converter, and performs thermal print control. The shift register 2 serially inputs print data from the CPU 1. The latch register 3 receives the latch signal and latches the contents of the shift register 2. The gate circuit 4 selectively drives the drive transistor 5 according to the contents of the latch register 3 when the strobe signal is applied. In FIG. 1, reference numeral 6 denotes a heating element that constitutes each dot of the line thermal head, and is composed of, for example, a heating element for 384 dots. The drive transistor 5 drives each of these heating elements. The p-channel FET (Q3) is a heating element 6 of the thermal head.
The battery power supply voltage VB to be applied to the common side is switched. The transistor Q1 controls the gate of Q3 in accordance with the output of the port P1 of the CPU 1 to perform switch control. The transistor Q2 is turned on / off by the output of the port P2 of the CPU1, and supplies the reference voltage Vref to the common side of the heating element 6 through the resistor R1 and the diode D1 in the on state. The CPU 1 reads the potential at the point A from the analog input port A1.

When performing some kind of print control in FIG. 1, the CPU 1 sets the port P1 to "H" to turn on Q1, thereby turning on Q3. Port P
5 and output serial data from port P6
Outputs a transfer clock signal. Thus, the print data for all the heating elements is set in the shift register 2. After setting the print data for all dots, the port P4
Is valid, and the contents of the shift register 2 are latched by the latch register 3. Thereafter, a strobe signal is output from the port P3, and the heating element 6 is selectively driven based on the contents of the latch register 3. Power is supplied to the selected heating element only while the strobe signal is at “H”. An optimum value is set for the “H” level period of the strobe signal (heating element energizing time) according to the resistance rank of the thermal head obtained by measurement as described later.

FIG. 2 is a flowchart showing a procedure for measuring the resistance value of each heating element and a procedure for setting the energizing time. Hereinafter, the operation will be described with reference to FIGS.

This process is performed, for example, when the power is turned on. The CPU first sets the port P1 to "L" to turn off Q1, thereby shutting off Q3 (n1). Subsequently, the port P2 is set to “L” to turn on Q2 (n
2). As a result, the reference voltage Vref changes from Q2 → R1 → D1
→ Provided to the common side of each heating element via route 6. Thereafter, the initial value 1 is set to the number (dot number) DN of the heating element to be energized (n3).

Then, print data corresponding to the dot number DN is set in the latch register 3 via the shift register 2 (n4). That is, data is set in the latch register so that the DN-th bit is set to 1 so that the heating element of the number indicated by DN is energized, and all other bits are set to 0. For example, if DN = 1, the contents of the latch register are 1000... After that, port P3
Is set to "H" to output a strobe signal (n5). As a result, the AND output of the bit in which 1 is set in the latch register 3 becomes “H”, and the drive transistor 5 of the dot corresponding to bit 1 becomes conductive. In the above example, when the dot number DN = 1, Vref → Q2 → R1 → D1
Electricity is supplied through the path of → 6a → 5a, and the potential at point A is determined by the resistance value of the heating element 6a. Vref, V _{CE of} Q2,
R1 resistance, D1 forward voltage drop and 5a V _CE
Since is already known, the resistance value of the heating element 6a can be finally obtained from the potential at the point A. The CPU 1 inputs the potential at the point A from the analog input port A1 and performs A / D conversion (n6). Thereafter, the port P3 is set to "L" to terminate the energization of the measured heating element (n7). Note that the reference voltage V
Since ref is about の of the battery voltage VB and the energizing time is short, the energization at the time of measuring the resistance value does not cause the printing paper to thermally develop color. Steps n4 to n shown in FIG.
Until the dot number DN reaches the final value 384, the processing of step 7 is incremented and sequentially repeated (n8 → n9 → n4...). After measuring the resistance values of all the heating elements of 384 dots in this way, the average value of the resistance values is obtained (n10). After that, an energizing time required for printing is obtained from the obtained average resistance value, and the value is set (n11). Subsequently, it is determined whether or not the current mode is the resistance value printing mode (n12). This resistance value printing mode is a mode that is set, for example, when a dip switch is set or when the power is turned on in a specific key operation state. In the resistance value printing mode, the resistance value of each dot obtained in step n6 is printed, and statistical values such as the number of dots within the normal resistance value range, the maximum resistance value, the minimum resistance value, and the average resistance value will be described later. Printing is performed as in the example (n13 → n14). If the mode is not the resistance value printing mode, the operation proceeds to a predetermined operation. Thereafter, for example, when performing normal print control, the width of the strobe signal is controlled based on the data of the energization time set in step n11. Thus, optimal energy can be applied to the heating element of the thermal head, and high-quality printing can be performed.

FIG. 3 shows an example of resistance value printing in the resistance value printing mode. In FIG. 3, [DOT] is a dot number [HEX] of the heating element, and the resistance value of each dot is represented in hexadecimal. For example, the resistance value of dot 1 is 80
(The resistance value is normalized by 8 bits from 00 to FF), the resistance value of dot 2 is 7F, and the resistance value of dot 3 is 8
0, and the resistance value of the dot 384 is 81. After sequentially printing out the resistance value of each dot as described above, the number of dots falling within a predetermined normal resistance value range is printed, and the maximum resistance value, the minimum resistance value, the average resistance value, and the like are sequentially printed.

In the above-described embodiment, the resistance value of each heating element is simply arithmetically averaged to obtain a representative resistance value. However, as another method, a mode, a median, or the like may be obtained as a representative value. .

[0019]

According to the thermal printer control device of the present invention,
According to the thermal printer controller, the thermal printer
The resistance value of each heating element that composes the head can be read.
The thermal head is good or bad, and
Can be easily grasped.

In addition, according to the resistance rank of the thermal head,
Because there is no need to set the same rank, the thermal head
Incorporation of the printer mechanism into the device body has been simplified,
There is no reduction in print quality due to incorrect settings. In addition, thermal
Automatically follow the resistance change with the aging of the pad
High-quality printing control.
Wear. Furthermore, when the resistance value of each heating element is measured, the printing paper does not develop heat-sensitive color, so that the paper is not wasted.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a thermal printer control device according to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating a processing procedure of a main part of the thermal printer control device according to the embodiment of the present invention.

FIG. 3 is a diagram illustrating an example of resistance value printing.

[Explanation of symbols]

 6-heating element VB-battery voltage Vref-reference voltage

Claims (2)

(57) [Claims] 1. A thermal printer comprising a register for inputting print data for each heating element of a thermal head, and a heating element drive circuit for selectively driving a heating element to be energized according to the state of each bit output of the register. In the control device, while energizing each heating element of the thermal head individually,
A resistance measuring means for measuring the resistance of each heating element, a thermal printer control apparatus provided with a resistance value print control means for sequentially providing to said register the resistance value of each heating element is measured as the print data. 2. The method according to claim 1 , wherein each of said resistance values measured by said resistance value measuring means is determined.
A representative resistor for calculating the representative resistance value of the heating element from the resistance value of the heating element
Resistance value calculating means, and the heating drive based on the representative resistance value
Power supply time control means for controlling the power supply time of the circuit.
2. The thermal printer control device according to claim 1 , wherein the resistance value measuring unit measures the resistance value of each heating element by applying energy smaller than the energy applied to the heating element during printing.