JPH04201460A - Constant temperature device for thermal head - Google Patents

Abstract

PURPOSE:To heat and cool a head efficiently and keep a constant temperature of the heated head with a structure simplified and low in cost by operating a Peltier element whose one face and other face have a relationship of heating and cooling with each other in response to a predetermined signal. CONSTITUTION:A Peltier element 32 is stuck between a thermal head 21 and a support member 33, having a width same as that of the thermal head 21, and fixed interposingly so as to cover the upper face where a heat generating resistor 23 and a thermistor 27 are provided. The Peltier element 32 has a cooling face on one side and a heating face on other side. The cooling face and the heating face are reversed by reversing a polarity of a current to be supplied to these faces. A resistance value data based on a temperature from the thermistor 27 is supplied to a temperature processing circuit, where a first set value in the high temperature set previously is compared with a second set value in the low temperature. When the data indicates a temperature higher than the first set value, a cooling signal is outputted. When the data indicates a temperature lower than the second set value, a heating signal is outputted.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a constant temperature device for a thermal head used in a thermal transfer and printing mechanism of a thermal printer.

(Prior art) Conventionally, in devices that record using a thermal head,
When printing continuously, the head temperature rises and the print density increases, making it impossible to obtain the correct color gradation. Measures are being taken.

Additionally, in devices that use this thermal head, the head temperature when printing the first page is affected by the outside temperature, so it is necessary to keep the head temperature constant in order to obtain accurate gradation. , a heater is built into the head or head mounting member for heating.

FIG. 5 is a diagram of a conventional example of a constant temperature device for a thermal head for boat fishing.

In the figure, reference numeral 1 denotes a thermal head, which is composed of an aluminum base 2, a ceramic base 4 having a heating resistor 3, and a heating element resistance drive circuit board 5 fixed to each other.

6 is a protective cover for the drive circuit board 5, and 7 is a side heating element such as a thermistor, which detects the head temperature.

A heater 11 is disposed between the head 1 and the support member 8, and when the temperature of the thermal head 1 is below a predetermined temperature, the temperature is raised by the heating of the heater 11.

On the other hand, when the temperature of the thermal head 1 is higher than a predetermined temperature, heat is radiated by the heat radiation fins 9 integrally formed on the upper surface side of the support member 8, and the thermal head 1 is forcibly cooled by the cooling fan 10.

In addition, as another conventional device, a device configured to perform forced cooling using an electronic cooling element is also known (Utility Model Application No. 57-57947).
(see publication).

(Problems to be Solved by the Invention) Therefore, in the conventional device, the head support member has a large heat capacity, takes time to cool and heat, is not easy to assemble, and requires a large space for installation. It was something that would end up happening.

In particular, in the device of the first conventional example, since the heater and the cooling fan are separated from each other, and the thermistor and the heating element are separated from each other, the heating element is heated to a predetermined temperature T.
Since the thermistor resistance value when the temperature reaches ``C'' and the thermistor resistance value when the temperature of the heating element during cooling is ``T''C are different, it is necessary to provide separate heater cooling fan drive circuits for each, which increases costs. It had the following problems.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to improve the efficiency of the heating and cooling time of the head, and to provide a device that has a simple and inexpensive configuration to maintain a constant temperature of the heating head. do.

(Means for Solving the Problems) In order to achieve the above object, the apparatus of the present invention has the following configuration.

That is, in a constant temperature device for a thermal head that has a thermal head that is heated by a heat generating part to record characters or images, and in which the heat of the heated thermal head is radiated by a heat radiating part, the thermal head and other parts are placed on the - side. a Bertier element provided with the heat dissipation section on its surface side; a temperature information detection section that detects temperature information of the thermal head; and a control circuit that supplies a predetermined signal to a Beltier element, and in response to the predetermined signal, one side and the other side of the Beltier element have a heating and cooling relationship with each other to operate the Beltier element. A constant temperature device for a thermal head characterized by the following.

(Function) A Peltier element is arranged to have a thermal head on one side and a heat dissipation part on the other side, and the one side and the other side of the Beltier element are heated together by a predetermined signal based on temperature information of the thermal head. The Vertier element is operated with a cooling relationship.

(Example) An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a perspective view of a constant temperature device for a thermal head according to an embodiment of the present invention, and FIG. 2 is a schematic cross-sectional view.

In the figure, reference numeral 21 indicates a thermal head, and a ceramic base 24 has a heating resistor 23 on an aluminum base 22.
A heating resistor driving circuit board 25 is fixedly held.

Further, a thermistor 27 is installed near the heating element drive circuit board 25.
or fixed.

26 is a protective cover for the heating element drive circuit board 25.

FIG. 3 is a schematic enlarged view of the heating resistor 23. In the same figure, a heat storage layer called a brace layer 29 is provided between the ceramic base 24 and the heating portion 28 held between the electrodes 30, 30. By keeping the temperature of the brace layer constant, the printing temperature can be kept constant.

Note that 31 is a protective layer.

When the grace layer 29 is heated by the heat generating portion 28, the heat is radiated to the aluminum base 22 side, which has a large heat capacity and is lower in temperature than the brace layer 29.

Temperature information of the aluminum base 22 due to this heat radiation is detected by a thermistor 27.

The aluminum base is fixedly held by screws 35 to a support member 33 located on the upper side with the Beltier element 32 sandwiched therebetween.

The Bertier element 32 is in close contact between the thermal head 21 and the support member 33, has a width equal to the width of the thermal head 21, and is arranged so as to cover the upper surface position where the heating resistor 23 and thermistor 27 are provided. The clamp is fixed.

Furthermore, a radiation fin 37 is integrally formed on the upper side of the support member 33.

39 is a bottle for attaching to a printer device (not shown).

The Vertier element 32 has one side as a cooling surface and the other side as a heating surface, and is configured such that the cooling surface and the heating surface are reversed by reversing the polarity of the current flowing therein.

In this Beltier element 32, when the temperature on the aluminum base 22 side becomes higher than a predetermined value, the aluminum base 22
By making the second side a cooling surface, making the radiation fin 37 side a heating side, and cooling this heating surface side with the radiation fins 37,
It becomes possible to efficiently cool the aluminum base 22 side.

Conversely, if the temperature falls below the predetermined temperature, the aluminum base 22 side is used as the heating surface and the radiation fins 37 are used as the cooling surface.
The thermal head 21 can be heated efficiently.

FIG. 4 is a driving circuit diagram of the Beltier element 32.

In the figure, reference numeral 50 denotes a head power source, which serves as a common power source for the heat generating section 28 and the Bertier element 32.

Resistance value data based on the temperature from the thermistor 25 is supplied to the temperature processing circuit 51, which compares a first set value on the high temperature side and a second set value on the low temperature side that have been set in advance, and calculates the first set value.
If the data indicates a higher temperature than the second set value, a cooling signal is output, and if the data indicates a temperature and humidity higher than the second set value, a heating signal is output.

Further, if the data indicates an intermediate temperature between the first and second set values, a non-output state occurs and the operation of the Vertier element 32 is stopped.

When a cooling signal is output from the temperature processing circuit 51, the signal is amplified by the transistor 53 through the OR circuit 52 at the next stage, and the Bertier element 32 is activated through the A contact side of the relay 54.

As a result, the head contact surface side is cooled, and the cooling fins 37
The side is heated.

Conversely, when a heating signal is output from the temperature processing circuit 51, the heating signal passes through the OR circuit 52 and is amplified by the transistor 53, turning on the relay 54, and amplifying the heating signal at the stage before the OR circuit 52. The branched heating signal is amplified by the transistor 56, and the contact pieces of the relay 55 are respectively connected to the B contact side to reverse the polarity.

At this time, the head contact surface side is heated, and the cooling fin 37 side is cooled.

Further, this cooling or heating signal is supplied to a mechanical control circuit (not shown), and when any of these signals is supplied, the printing operation is stopped, and the printing operation on new paper is stopped.

(Effects) Therefore, the apparatus of the present invention has a thermal head that is heated by a heat generating part to record characters or images, and in a constant temperature device for the thermal head in which the heat of the heated thermal head is radiated by a heat radiating part. - a Bertier element in which the thermal head is provided on one surface side and the heat dissipation section on the other surface side; a temperature information detection section that detects temperature information of the thermal head; a control circuit that supplies a predetermined signal to the Beltier element based on a comparison with a set temperature, and one side and the other side of the Beltier element have a heating and cooling relationship with each other in accordance with the predetermined signal. Since the thermal head constant temperature device is characterized in that the Bertier element is configured to operate, for example, when the Bertier element is cooling the head, the heat radiation part side can be used as the heating surface side, and when the head is heated, the heat radiation part side can be used as the heating surface side. Since it can be placed on the cooling surface side, the head and the heat container in the vicinity thereof can be made smaller, and the cooling and heating times can be made faster.

In addition, cooling and heating can be performed by supplying a predetermined signal to the Beltier element, and the structure is simple, inexpensive, easy to work with, and space-saving.

Furthermore, since heating and cooling can be performed using a Beltier element, constant temperature can be easily maintained.

Furthermore, since the heating and cooling devices can be the same, it is possible to easily maintain a constant relationship between the temperature information value and the heat generating portion during heating and cooling.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of a constant temperature device for a thermal head according to an embodiment of the present invention, Fig. 2 is a schematic sectional view thereof, Fig. 3 is a schematic enlarged view of a heating element, and Fig. 4 is a driving circuit of a Bertier element. 5 and 5 are diagrams of a conventional example of a constant temperature device for a thermal head. 21... Ceramic base, 22... Aluminum base, 23... Heating resistor, 27... Thermistor, 32... Vertier element, 37
...Radiating fin, 51...Temperature processing circuit, 52...OR circuit, 53.
56...Transistor, 54.55...Relay. Patent applicant: Victor Japan Co., Ltd. Figure 1

Claims (1)

[Scope of Claims] A constant temperature device for a thermal head that has a thermal head that is heated by a heat generating part to record characters or images, and that radiates the heat of the heated thermal head by a heat radiating part, a Peltier element in which the heat radiation section is provided on the other side of the head; a temperature information detection section that detects temperature information of the thermal head; and a temperature information detection section that obtains the temperature information and combines this temperature information with a preset temperature. and a control circuit that supplies a predetermined signal to the Peltier element by comparison, and in accordance with the predetermined signal, one side and the other side of the Peltier element have a heating and cooling relationship with each other to control the Peltier element. A constant temperature device for a thermal head, characterized in that it is configured to operate.