JPH0970992A - Printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily secure a high temperature region suitable for printing/erasing by providing a preheating means that preheats a thermal head every prescribed time period. SOLUTION: On a thermal head 12, multiple heating resisters 21... are provided on an overall head face at prescribed intervals and preheating resisters 22... are provided between the respective heating resisters 21.... When a power us turned on, each of the heating resisters 21... is heated to an operation temperature. A current is controlled to be applied to each of the preheating resisters in accordance with a preheating signal so that each is heated to an optimum preheating temperature. That is, a CPU outputs the preheating signal to control the current to each of the preheating resisters. In terms of the preheating signal at that time, a pulse signal having ON and OFF states is outputted so that the preheating resister is preheated every prescribed time interval. The current value to the preheating resister 22 is adjusted corresponding to the resistance value R of the resister 22. As a result, a heating temperature range becomes small, thereby readily obtaining a heating quantity suitable for printing/erasing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing device for printing / erasing on a recording medium such as a rewrite card,
More specifically, the present invention relates to a printing device capable of performing stable printing processing with a low heat amount.

[0002]

2. Description of the Related Art Generally, this type of printing apparatus prints / erases on a recording medium such as a rewrite card, which is used for repeatedly printing by heating a thermal head. Further, when the processing time is shortened along with the high speed printing of the recording medium, it is necessary to shorten the heating time of the thermal head.

However, when printing / erasing with this thermal head, the temperature is rapidly heated from room temperature to a high temperature range.
It took a certain heating time and was not suitable for high-speed processing. Further, it is possible to increase the heating output to rapidly heat the thermal head to a high temperature region in a short time, but in this case, the protective layer and the recording layer of the recording medium are likely to be affected by the instantaneous high temperature and deteriorate, The durability of the recording medium will be reduced.
Further, in the current thermal head, the temperature rises gradually due to the high temperature heat storage effect during continuous processing, which causes printing unevenness.

Therefore, printing / erasing can be performed in a short time if the thermal head is preheated and slightly heated during printing / erasing. In this case, it is appropriate for high temperature heat storage. Since no measures have been taken, uneven printing cannot be completely eliminated, and printing with high processing performance on a recording medium has been desired.

[0005]

SUMMARY OF THE INVENTION Therefore, according to the present invention, not only is the thermal head preheated, but the preheating temperature is adjusted to easily secure a high temperature region suitable for printing / erasing. For the purpose of provision.

[0006]

According to the first aspect of the present invention,
A printing apparatus for heating / heating a thermal head to print / erase on a recording medium, characterized by comprising preheating means for preheating the thermal head at regular time intervals.

According to a second aspect of the present invention, there is provided detecting means for detecting the outside air temperature, and setting changing means for changing the preheating temperature of the thermal head to a temperature suitable for the outside air temperature detected by the detecting means. Is characterized by.

According to a third aspect of the present invention, there is provided control means for shortening the heating time of the thermal head.

[0009]

According to the present invention, the thermal head is preheated at regular time intervals by the preheating means to stand by for printing, and the thermal head is heated at the time of printing / erasing to perform printing / erasing on the recording medium.

Similarly, when printing / erasing on a recording medium, the outside air temperature is detected by the detecting means, and the thermal head is set by the setting changing means so that the preheating temperature is suitable for the detected outside air temperature. The recording medium is made to stand by and heated in this waiting state to perform printing / erasing.

When printing / erasing a recording medium,
If the thermal head is already in a high temperature range such as continuous printing, the heating time of the thermal head is shortened by the control means.

[0012]

As a result, since the thermal head is preheated before the printing process, the heating amount of the thermal head can be small during the printing process, and the printing process can be performed by heating the thermal head in the printing allowable temperature range in a short time. . Moreover, since the preheating temperature can be set in a constant temperature region by preheating at regular time intervals instead of continuous preheating, the thermal head does not generate high temperature heat storage,
Stable printing can be performed.

Further, since the thermal head is heated from the preheating temperature, the heating temperature width becomes small, and the printing / printing of the recording medium is performed.
A heating amount suitable for erasing can be easily obtained, deterioration of the protective layer and recording layer of the recording medium can be suppressed, and if the preheating temperature of the thermal head is adjusted according to the outside air temperature, it is suitable for the surrounding environmental temperature. It can be printed / erased. Further, if the thermal head is already in a high temperature range for continuous printing or the like, the heating time can be shortened and the temperature range can be set to a temperature range suitable for printing / erasing, and printing processing can be performed to eliminate uneven printing.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a rewrite card printing apparatus. This rewrite card printing apparatus prints transaction data by bringing a heated thermal head 12 into contact with the surface of a rewrite card 11 for each card transaction.
A heating voltage (resistor) 14 is caused to generate heat by applying a printing voltage to the second electrode 13, and the heat generation amount is brought into thermal contact with the rewrite card 11 via the head protection layer 15.

The above-mentioned rewrite card 11 has the protective film layer 1
6 and the heat sensitive layer 17 and the substrate layer 18 are laminated in this order and integrally molded. Of these, the heat sensitive layer 17 is made of a large number of low molecular weight organic substances contained in the resin material transparent in a specific temperature range. It has a thermoreversible property that changes into a single crystal that exhibits a color and a polycrystal that exhibits a white turbid color by diffusely reflecting light. The heat sensitive layer 17 is heated by the thermal head 12 described above to obtain a white turbid color and a transparent color. Characters of transaction data are printed on the surface of the card by providing a contrast difference between the two, and the thermal head 12 makes contact with the surface of the card to apply a specific temperature to erase the characters printed on the surface of the card. Further, the heat sensitive layer 1
The surface of 7 is covered with a thin protective film layer 16 which is transparent and has good heat resistance, and the entire one surface of the rewrite card 11 is provided in a heat-sensitive print field.

FIG. 2 shows a heating configuration of the thermal head 12. This thermal head 12 has a large number of heating resistors 21 ... Arranged at regular intervals over the entire head surface, and these heating resistors are also arranged. The preheating resistors 22 are interposed between the bodies 21, and the heating resistors 21 heat up to the processing temperature when the power is turned on, and the current is controlled to flow to the preheating resistors 22 based on the preheating signal. By this flow control, the preheating resistors 22 ... Generate heat at the optimum preheating temperature.

Further, CLK, DATA, L necessary for printing
Control signals such as ATCH and ENBLE are transferred to the shift register 2
3 and the latch 24, and each heating resistor 21 is heated based on this control signal to perform printing / erasing processing.

FIG. 3 is a block diagram of a control circuit of the rewritable card printer, in which the CPU 31 outputs an analog signal from each heating resistor in the thermal head 12 to a signal processing circuit 32.
Then, the voltage value is digitized by the A / D converter 33 and collated with the table data in the memory 34 to detect the temperature of the thermal head 12.

Further, the CPU 31 outputs a preheat signal to control the current to the preheat resistor, the preheat signal at this time is preheated at a constant time interval by the ON / OFF output of the pulse signal, and the resistance R is large. Adjusts the amount of current to the preheat resistor. Further, the CPU 31 outputs a control signal necessary for printing to the thermal head 12 to perform a printing operation with an optimum value.

FIG. 4 shows the preheating state and the heating state of the thermal head. The heating resistor is heated by the heating timing signal 41, at this time, the heating change curve 4 of the heating resistor.
2 rises on the basis of the preheat temperature 43 raised to the preheat temperature 43 and reaches the print permissible temperature region 44 in a short time to complete heating, and keeps the temperature region 44 for a long time for the effective print processing time 45. It can be secured for a long time, and the heating peak temperature 46 when heated can be set low.

As described above, since the heating resistor is heated from the preheating temperature, the heating temperature width is reduced, and the heating amount suitable for printing / erasing the rewrite card 11 can be easily obtained. In particular, the preheating resistor is not preheated continuously but can be preheated at regular time intervals to control the temperature within a constant preheating temperature range. Instead, optimum temperature control is performed and stable printing can always be performed. In addition, since it is possible to prevent abnormally high temperatures due to high temperature heat storage,
The deterioration of the first protective film layer 16 and the heat sensitive layer 17 can be suppressed, and the life can be extended.

For reference, a heating change curve 47 of the heating resistor when not preheated is shown by an imaginary line in FIG. In this case, since it takes a long heating time to reach the print permissible temperature region 44, and the effective print processing time 48 after heating is short, the print processing is insufficient, and the heating peak temperature 49 becomes high. It is recognized that the high temperature heat storage 50 is likely to occur.

By the way, when controlling the preheating temperature, it is set so that a stable preheating temperature can be obtained regardless of the outside air temperature. This is because the detection function for detecting the outside air temperature is connected to the CPU 31, and the temperature of the preheating resistor is adjusted by the CPU so that the optimum preheating temperature corresponding to the detected outside air temperature is reached.
The temperature is controlled so that the setting can be changed at 31.

As a result, even if the ambient temperature of the rewrite card printer changes greatly, the optimum preheat temperature can be changed to follow the change, and the reference preheat temperature suitable for the print / erase processing performance is always maintained. be able to.

FIG. 5 shows a case where the heating time interval of the preheating resistor is adjusted. During the printing process, the heating amount of the heating resistor is added to the preheating amount of the preheating resistor, and the thermal head itself is excessively heated. Therefore, the current flowing through the preheating resistor is reduced during the printing process to shorten the heating time of the preheating resistor.

Further, even when the thermal head is already in a high temperature range due to continuous printing or the like, the heating time of the preheating resistor is shortened and adjusted to a constant preheating temperature range. As a result, the thermal head is optimally temperature-controlled and can always perform stable printing processing suitable for printing / erasing without uneven printing.

FIG. 6 shows an example in which the temperature of the preheating resistor is adjusted. In this example, a large number of preheating resistors 61a, 61b ... In the thermal head are divided into several blocks, and the preheating resistors 61a, 61b for each of these blocks are divided. ... for each preheat signal line 62
The a and 62b are connected, and the preheating amount is changed in two stages depending on whether both signals are turned on or one signal is turned on to switch the preheating temperature.

FIG. 7 shows an example of adjusting the temperature of the preheating resistor in the same manner, and one preheating resistor 71 has a plurality of resistors R.
The preheating amount of the preheating resistor is adjusted and controlled by connecting 1 and R2 and adjusting the magnitude of the current flowing through them.
The amount of preheating can also be adjusted by changing the output pulse width and pulse period of the preheating signals 72 and 73.

As described above, since the thermal head is preheated before the printing process, the heating amount of the thermal head can be small during the printing process, and the printing process can be performed by heating the thermal head in the printing allowable temperature range in a short time. . Moreover, since the preheating temperature can be set in a constant temperature region by preheating at regular time intervals instead of continuous preheating, the thermal head does not generate high temperature heat storage, and stable printing can be performed from beginning to end. Also, since the thermal head is heated from the preheating temperature, the heating temperature range is narrowed, and the amount of heat suitable for printing / erasing the rewrite card can be easily obtained, and the deterioration of the protective film layer and heat sensitive layer of the rewrite card can be suppressed. Moreover, since the preheating temperature of the thermal head can be adjusted to a temperature suitable for the outside air temperature, stable printing processing can be performed regardless of the ambient temperature.
If printing is in progress, shorten the heating time
It is possible to adjust the temperature range suitable for erasing and perform printing processing without uneven printing.

In the correspondence between the present invention and the configuration of the above-described embodiment, the printing apparatus of the present invention corresponds to the rewrite card printing apparatus of the embodiment, and hereinafter, the recording medium corresponds to the rewrite card 11. , The preheating means is each preheating resistor 2
2, 61a, 61b, 71, and the detection means, the setting change means, and the control means correspond to the CPU 31, but the present invention is not limited to the configuration of the above-described embodiment.

[Brief description of drawings]

FIG. 1 is an enlarged longitudinal sectional view of an essential part showing a heated state of a rewritable card printer according to the present invention.

FIG. 2 is a circuit explanatory diagram showing a circuit configuration of a thermal head of the present invention.

FIG. 3 is a block diagram of a control circuit of the rewrite card printing apparatus of the present invention.

FIG. 4 is a waveform diagram showing preheating and heating states of the rewrite card printing apparatus of the present invention.

FIG. 5 is a waveform explanatory view showing a shortened heating state of the thermal head of the present invention.

FIG. 6 is a principal part explanatory view showing another example of the circuit configuration of the preheating resistor of the present invention.

FIG. 7 is a principal part explanatory view showing another circuit configuration example of the preheating resistor of the present invention.

[Explanation of symbols]

 11 ... Rewrite card 12 ... Thermal head 21 ... Heating resistor 22, 61a, 61b, 71 ... Preheating resistor 31 ... CPU 42 ... Heating change curve 43 ... Preheating temperature 44 ... Printing allowable temperature region 45 ... Effective printing processing time

Claims (3)

[Claims] 1. A printing apparatus for heating / heating a thermal head for printing / erasing on a recording medium, the printing apparatus having a preheating means for preheating the thermal head at regular time intervals. 2. The printer according to claim 1, further comprising: a detection unit that detects the outside air temperature; and a setting change unit that changes the preheating temperature of the thermal head to a temperature suitable for the outside air temperature detected by the detection unit. . 3. The printer according to claim 1, further comprising control means for shortening the heating time of the thermal head.