JPH05147254A - Label printer - Google Patents

Abstract

PURPOSE:To maintain and to uniformize print quality by making it possible to decide a supply voltage with regard to temperatures of a thermal head and a paper, whereas a supply voltage, compensated by a supply voltage compensa tion means, is applied to a thermal head instead of that preset by a supply voltage setting means. CONSTITUTION:The data of a supply voltage (V) calculated by a supply voltage compensation means is stored instead of the data of a supply voltage (V1) stored in a setting area by a compensation supply voltage setting means. Consequently, the supply voltage data stored in the setting area is outputted and the thermal head is supplied with that voltage by a head voltage supply means, whereby a label is printed and published. After publishing the label, an adding operation that adds +1 to a counter K is carried out and it is judged whether or not the counted number becomes the same as the number of continuous publishing labels predetermined as the number of designated publishing labels. When the number of the counter K does not become the number of continuous publishing labels N, the previous operations are carried out until the counted number reaches N, and then the printing and publishing operations are terminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a label printer for printing on paper by controlling the voltage of a thermal head.

[0002]

2. Description of the Related Art In conventional label printers, a label paper is printed by a thermal head whose voltage is controlled. The voltage control of the thermal head is performed by, for example, direct printing using a thermal paper or transfer printing using an ink ribbon, the rank of the resistance value (head resistance value) of the heating resistor forming the thermal head, the printing speed, the thermal Since the voltage value applied to the thermal head varies depending on factors such as head temperature, a table is preset in memory that contains the optimum applied voltage data corresponding to the combination of these factors. The applied voltage data corresponding to the combination of those elements at that time was read, and the voltage was applied to the thermal head based on the read applied voltage data.

[0003]

By the way, in the case of continuously printing a plurality of labels at a high speed, as shown in FIG. 6, the thermal head is largely heated by the heat generated by the thermal head itself to reach a high temperature, and the ambient temperature is increased. The difference between the temperature A and the temperature B of the thermal head becomes large.

Generally, in order to print with a set print density, the thermal head needs to reach a predetermined printing temperature. Therefore, the temperature of the thermal head is detected, and the printing temperature is reached from the detected temperature. The applied voltage calculated from the heating amount necessary for the above was set in the table provided in the memory. In other words, in the conventional label printer,
The applied voltage set in the table is set with the temperature of the thermal head as an element, and the temperature of the paper is not taken into consideration. Therefore, when the temperature difference between the thermal head and the paper becomes considerably large, there is a problem that the applied voltage according to the applied voltage data read from the table causes the printing to be thin.

Therefore, the present invention provides a label printer capable of determining the applied voltage in consideration of the temperature of the paper together with the thermal head in the continuous printing of a plurality of labels at a high speed, and thus maintaining a uniform print quality. With the goal.

[0006]

SUMMARY OF THE INVENTION According to the present invention, in a label printer which is provided with a thermal head and controls a voltage applied to the thermal head to print predetermined print information on a sheet, the head detects the temperature of the thermal head. By the temperature detecting means, the applied voltage setting means for setting the applied voltage applied to the thermal head based on the temperature data obtained by the head temperature detecting means, etc., and the applied voltage setting means at the time of continuously issuing a plurality of labels and the like. Applied voltage correction means for correcting the set applied voltage based on a correction value set in advance with reference to the applied voltage at the start of continuous issuance, and the applied voltage set by the applied voltage corrected by the applied voltage correction means. The applied voltage set by the means is set in place of the applied voltage set by the means, and the set applied voltage is printed on the thermal head. It is provided with a head voltage application means for.

[0007]

In the present invention having such a structure, the temperature of the thermal head is detected by the head temperature detecting means, and the voltage is applied to the thermal head by the applied voltage setting means based on the temperature data obtained by the head temperature detecting means. The applied voltage is set. The applied voltage set by the head voltage applying means is applied to the thermal head, and the thermal head prints predetermined print information on the paper.

Further, when a plurality of labels and the like are continuously issued, the applied voltage set by the applied voltage setting means based on the temperature data obtained by the head temperature detecting means is
The applied voltage correction means corrects the applied voltage based on the preset applied value at the start of continuous issuance. The corrected applied voltage is set by the corrected applied voltage setting means in place of the applied voltage set by the applied voltage setting means. Then, the head voltage applying means applies the set applied voltage to the thermal head,
Predetermined print information is printed on the paper by the thermal head.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a circuit configuration of a main part of a label printer to which the present invention is applied. Reference numeral 1 is a CPU (central processing unit) which constitutes a control unit main body.
A ROM (read only memory) 2 stores program data executed by the CPU 1, and a RAM (random access memory).
memory) 3 is formed with areas of various memories used when the CPU 1 performs processing, and further is a combination of direct printing or transfer printing as shown in FIG. 2, rank of head resistance, and temperature of thermal head. The temperature table 3a in which the data of the applied voltage to the thermal head is set corresponding to the above is formed for each printing speed (not shown), and the direct printing or transfer printing shown in FIG. Correspondingly, the correction constant table 3b in which the correction constant value C is set is formed. The communication I / F (interface) 4 is connected to the host computer via a line. The CPU 1 has the ROM 2, the RAM 3, and the communication I / F 4 via the system bus 5.
Connected with.

The head controller 6 is a thermal head 7.
The motor controller 8 controls the stepping motor 9 for conveying the paper, and the A / D (analogue / d
igi-tal) converter 10 is a temperature sensor 11 as a head temperature detecting means for detecting the temperature of the thermal head 7.
The detection data from is input, and the detection data is converted into digital data and output. The CPU 1 is also connected to the head controller 6, the motor controller 8 and the A / D converter 10 via the system bus 5. FIG. 4 shows the flow of the print issuing process performed by the CPU 1.

First, the counter k formed in the RAM 3 is set to "0", the temperature data detected by the temperature sensor 11 is read, and RA is calculated based on the temperature data.
From the temperature table 3a formed on M3, the applied voltage (V
The data of 0) is read and the read data of the applied voltage (V0) is stored in the setting area for the applied voltage formed in the RAM 3 as the applied voltage data at the start of the continuous issue. (Applied voltage setting means)

Here, it is judged in advance whether or not the designated number of sheets is issued to instruct the continuous issuance of a plurality of labels, and if the designated number of sheets is not issued, the applied voltage (V
0) data is output, and the voltage (V0) is applied to the thermal head 7 (head voltage application means), and the label 1
Issue printouts of sheets. When one label is issued, this print issuing process is finished.

If the designated number of sheets is issued, step 1
(ST1), the temperature data detected by the temperature sensor 11 is read, the data of the applied voltage (V1) is read from the temperature table 3a based on the temperature data, and the data of the applied voltage (V0) is read. Instead of this, it is stored in the setting area. (Applied voltage setting means)

At this time, the newly stored data of the applied voltage (V1) is subtracted from the data of the applied voltage (V0) stored in the setting area at the start of continuous issuance, and the value is 0.
If it is below, proceed to the next processing as it is, and the numerical value is 0.
If it is larger, the correction constant value C is read from the correction constant table 3b, and the data of the applied voltage (V1) stored in the setting area is upwardly corrected by the following equation. When the corrected applied voltage is V, V = (V0) (1-C) + C (V1) (Applied voltage correction means) The data of the applied voltage (V) calculated here is stored in the setting area. The applied voltage (V1) is stored instead of the data. (Corrected applied voltage setting means)

Next, the applied voltage data stored in the set area is output, and the voltage is applied to the thermal head 7 (head voltage applying means) to print one label. When one label is issued, + for counter k
An addition process of 1 is performed, and it is determined whether or not the count of the counter k is equal to the number N of consecutively issued sheets set in advance as the designated number of sheets.

If the count of the counter k is not equal to the number N of continuously issued sheets, the process is returned to the above-mentioned processing of step 1 (ST1). If the count of the counter k is equal to the number N of consecutively issued sheets, this printing is performed. The issuing process is terminated. In the present embodiment having such a configuration, it is received by the print issue command communication I / F transmitted from the host computer.

If the print issuing command is a command for issuing one label, the data of the applied voltage (V0) is read from the temperature table 3a based on the temperature data obtained from the temperature sensor 11 and set, and the applied voltage is further set. (V0)
Data is output and a voltage (V0) is applied to the thermal head 7. A single label is printed and issued by this applied voltage (V0).

If the print issuing command is a command for continuously issuing a plurality of labels, the data of the applied voltage (V0) is read from the temperature table 3a based on the temperature data obtained from the temperature sensor 11, and the continuous issuing is started. Set as the applied voltage data at the time. Then, based on the temperature data obtained from the temperature sensor 11 again for each printing of one label,
When the data of the applied voltage (V1) is read from the temperature table and set, and when the data of the set applied voltage (V1) becomes the data of the applied voltage lower than the data of the applied voltage (V0) at the start of continuous issuance, the data is continuously output. The data of the applied voltage (V1) is upwardly corrected by the following equation above based on the correction constant value C with the data of the applied voltage (V0) at the start of issuing as a reference. V = (V0) (1-C) + C (V1)

The corrected data of the applied voltage (V) is newly set, and the data of the applied voltage (V) is output to apply the voltage (V) to the thermal head 7. This voltage (V) prints and issues the one label.

FIG. 5 shows a graph of the voltage applied to the thermal head 7 at the temperature detected by the thermal head 7 by the temperature sensor 11. The graph E is based on the applied voltage data of the temperature table 3a which is not corrected. Here, when the ambient temperature, that is, the temperature of the paper is A, the applied voltage data read from the temperature table 3a at that time is applied to the thermal head 7. The voltage becomes V0. In contrast to such a graph, the voltage applied to the thermal head 7 is indicated by the alternate long and short dash line F based on the applied voltage data corrected by the correction constant value C described above.

For example, if the temperature of the thermal head 7 detected by the temperature sensor 11 after printing several labels continuously is G, the voltage applied to the thermal head 7 becomes V1 due to the uncorrected applied voltage data, The voltage applied to the thermal head 7 is V according to the corrected applied voltage data.

As described above, in the present embodiment, the correction constant value C is set according to the direct printing or the transfer printing and the printing speed.
If the applied voltage data is set to a lower applied voltage data than the applied voltage data at the start of the continuous issuing at the time of the continuous issuing, the set correction voltage table 3b is set at the start of the continuous issuing at the time of continuous issuing. By applying upward correction based on the correction constant value C with reference to the applied voltage data of 1, the applied voltage data can be corrected in consideration of the temperature of the thermal head 7 and the temperature of the paper. Therefore, according to the corrected applied voltage, the thermal head 7 can be heated to an appropriate temperature in consideration of the temperature of the paper for printing,
It is possible to prevent the print from becoming thin. That is, it is possible to maintain uniform print quality even in continuous printing.

[0024]

As described in detail above, according to the present invention,
In the continuous printing of a plurality of labels at a high speed, the applied voltage can be determined in consideration of the temperature of the paper together with the thermal head, so that it is possible to provide a label printer capable of maintaining uniform print quality.

[Brief description of drawings]

FIG. 1 is a block diagram showing a circuit configuration of essential parts of an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a temperature table of the same embodiment.

FIG. 3 is a diagram showing a configuration of a correction constant table of the same embodiment.

FIG. 4 is a diagram showing a flow of a print issuing process of the embodiment.

FIG. 5 is a diagram showing a graph of a voltage applied to the thermal head with respect to the temperature of the thermal head of the embodiment.

FIG. 6 is a diagram showing a graph of the temperature of the thermal head with respect to time during continuous issuing.

[Explanation of symbols]

1 ... CPU, 3a ... Temperature table, 3b ... Correction constant table, 7 ... Thermal head, 11 ... Temperature sensor.

Claims (1)

[Claims] 1. A label printer which is provided with a thermal head and controls a voltage applied to the thermal head to print predetermined print information on a sheet, and a head temperature detecting means for detecting the temperature of the thermal head, and the head. An applied voltage setting means for setting an applied voltage to be applied to the thermal head based on temperature data obtained by the temperature detecting means, and an applied voltage set by the applied voltage setting means when a plurality of labels or the like are continuously issued. The applied voltage at the start of the continuous issuance as a reference based on a preset correction value, and the applied voltage corrected by the applied voltage correction means is set by the applied voltage setting means. Applied voltage setting means for setting in place of the applied voltage, and applying the set applied voltage to the thermal head. And a head voltage applying unit.