JPH02206560A - Thermal transfer printing device - Google Patents

Abstract

PURPOSE:To control a cooling temperature in accordance with an ambient temperature around a heat-generating element by forming a a through hole through which a cooling liquid passes near the heat-generating element of a support member and installing a cooling device capable of making its cooling liquid flow variable in the through hole. CONSTITUTION:A through hole 22a is formed in parallel with a heat-generating element 21 inside an area near the heat-generating element 21 of a heat release plate 22 which supports the heat-generating element 21 of a thermal head. Pipes 26, 27 are connected to both ends of the through hole. The pipe 26 allows a cooling liquid 31 to be discharged into a tank 28, while the pipe 27 supplies the cooling liquid 31 from a pump 30 to the through hole 22a. An operating valve 35 is provided halfway through each branched pipe 33a of a deformed pipe 33 installed between the tank 28 and the pump 30. These operating valves 35 operate sequentially in response to an ambient temperature change around the heat-generating element 21 of the heat release plate 22. The cooling capacity of a cooling device 25 is controlled by increasing the number of the valves 35 which is released in accordance with a temperature increase due to the regeneration of heat in the element 21. Thus an ambient temperature around the heat-generating element 21 of the thermal head can be maintained at constant level.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thermal transfer printer device, and more particularly to a cooling device for a heat generating portion of a thermal head thereof.

[Conventional technology]

Generally, a thermal transfer printer device is configured as shown in FIG. That is, in the figure, 1 is a thermal head fixed on the printer device, 2 is a pressure roller, which is fixed to a support shaft 11, and both ends of the support shaft 11 are supported by two bearings (not shown). There is. 4 is a thermal transfer film, 5 is a printing paper printed by the printer device, 6 is a motor provided in the printer device, and a belt 7 stretched between the output shaft 6a and the support shaft 11.
Rotation is transmitted to the pressure roller 2 via the pressure roller 2.

In such a thermal transfer printer device, the power of the motor 6 is transmitted to the pressure roller 2 via the output shaft 6a, the belt 7, and the support shaft 11, and the thermal transfer film 4 and the printed image are conveyed by a traveling device (not shown). When the paper 5 stops just before the pressure roller 2 and the heating element of the thermal head 1 generates heat, the traveling device is driven again, and the thermal transfer film 4 and printing paper 5 are rolled and pressed by the pressure roller 2, and the thermal transfer film The transfer is performed onto the printing paper 5 by thermally melting the ink applied onto the printing paper 4.

[Problem to be solved by the invention]

However, as shown in the temperature characteristic diagram of FIG. 3, the temperature of the heating element of the thermal head 1 gradually rises after the thermal transfer printer starts transferring, and the temperature of the heating element of the thermal head 1 gradually increases until the transfer ends at E.
It will be quite high.

The temperature of the heating element will drop somewhat by the next transfer start time S, but the heat from the previous transfer has accumulated and the temperature will be higher by T('C) than at the previous transfer start time O. It has become. For this reason, there is a problem in that the density transferred to the printing paper 5 becomes darker as the temperature rises, deteriorating the print quality.

In order to prevent this, it would be ideal to keep the temperature around the heating element completely constant, but this is impossible because it would mean that 100% of the heat generated from the heating element would immediately escape. . However, it is possible to suppress the amount of heat accumulated around the heat generating element as much as possible. For example, it is possible to provide a huge heat dissipation fin around the heat generating element and cool the heat dissipation fin with a powerful fan. However, this solution has a problem in that there are significant restrictions when actually laying out the equipment.

Another solution is to force the area around the heating element.
For example, cooling with cooling water has been proposed, as specifically shown in FIG. 4 and published in Japanese Patent Application Laid-Open No. 59-202881. This thermal transfer printer device has a support shaft 11 as a hollow shaft, and its hollow interior is connected to a pipe 9 via a pair of seal joints 8, 8 provided at both ends thereof, and the inlet side and outlet of the cooling device 1o are connected to each other. The side is communicated with the hollow interior of the support shaft 11.

The seal joint 8 is designed to maintain airtightness by blocking the hollow interior from the outside air even when the support shaft 11 rotates. This thermal transfer printer device cools the pressure roller 2 by sending cooling water into the hollow interior of the support shaft 11 by the cooling device 10, thereby cooling the thermal head 1.
This system forcibly cools the area around the heating element.

However, in such a thermal transfer printer device, there is a risk that a conflicting problem arises in that the temperature rise of the heat generating element is suppressed, that is, the heat generation effect is impaired and the transfer operation is hindered.

As another solution, the time for the current to flow to the heating element of the thermal head 1 or the voltage etc.
There is a method of controlling the temperature to suppress the temperature rise; however, there is a problem in that devices and circuits are required for this purpose, which increases the cost of the entire device.

[Means to solve the problem]

Therefore, in order to solve the above-mentioned problems, the present invention provides a thermal transfer printer device that includes a heating element that heats printing ink and a heat radiating member that supports the heating element and radiates the heat stored in the heating element. A through hole through which a cooling liquid passes is formed in the vicinity of the heating element of the support member, and a cooling device capable of supplying the cooling liquid at a variable flow rate is provided in the through hole.

[For production]

According to the thermal transfer printer device having such a configuration, the heat dissipating member that supports the heat generating element and dissipates the heat stored in the heat generating element has a through hole through which the cooling liquid passes near the heat generating element, so that the heat transfer can be effectively carried out. In addition to being able to cool the area around the heating element, the flow rate of the coolant through the through holes is made variable by the cooling device, so the degree of cooling can be controlled according to the temperature around the heating element, and the temperature around the heating element is prevented from rising more than necessary. The cooling effect can be performed without suppressing the temperature. Therefore, it is possible to suppress the amount of heat accumulated around the heating element as much as possible without interfering with the transfer operation, prevent the transfer density from increasing steadily, and improve print quality.

〔Example〕

Embodiments of the present invention will be described below based on the drawings. FIG. 1 is a diagram showing an embodiment of a thermal transfer printer device according to the present invention.

In the same figure (a), 21 is a thermal head that heats and thermally melts the printing ink of the thermal transfer film (not shown) in order to transfer the printing ink of the thermal transfer film (not shown) to printing paper (not shown). It is a heating element. The heating element 21 of this thermal head is supported by a heat sink 22 (heat sink) made of aluminum or the like via a substrate (not shown) made of ceramic or the like. There is a heating element 2 inside the heat sink 22 near the heating element 21.
A through hole 22a is formed so as to be located parallel to 1.

Pipes 26 and 27 are connected to both ends of the through hole 22a, and the pipe 26 discharges the coolant 31 flowing inside it into the tank 28, and the pipe 27 supplies the coolant 31 from the pump 30 into the through hole 22a. used for Between the tank 28 and the pump 30, a plurality of (four) branch pipes 33a are formed on the -@ side, and a deformed pipe 33 is interposed, which is formed into one branch pipe on the other @ side. Each tip of the branch pipe 33a on one end side of the irregularly shaped pipe 33 is connected to the cooling liquid 31 of the tank 28.
The other end of the irregularly shaped pipe 33 is connected to the pump 30. Opening/closing valves 35 are provided in the middle of each branch pipe 33a of the irregularly shaped pipe 33, and are opened and closed sequentially in response to temperature changes around the heating element 21 of the heat sink 22. Pipes 26, 27. Tank 28° Pump 30. Coolant 31. Deformed pipe 33. The on-off valve 35 constitutes the cooling device 25 as a whole.

Other components include a pressure roller, a support shaft that fixedly supports this pressure roller, a motor that transmits rotation to this support shaft via a belt, a bearing that rotatably supports both ends of the support shaft, and heating by a heating element in a thermal head. The arrangement of the thermal transfer film, the printing paper on which the printing ink of the thermal transfer film that has been heated and melted is transferred and printed, etc., is the same as that of the conventional thermal transfer printer device shown in FIG. 2 described above. .

In such a thermal transfer printer device, when transfer is started as in the conventional printer described above, heat is accumulated in the heating element 21 of the thermal head and the temperature rises, but the heat is first transferred to the heat sink 22. Heat is absorbed and radiated. However, when the heat cannot be completely radiated even with this heat radiation effect, the temperature of the heating element 21 rises a little. For this reason, initially several (
Only one of the four on-off valves 35 is opened, and the pump 30 sucks up the coolant 31 from the tank 28 and supplies it to the through hole 22a of the heat sink 22. Cooling device 2 at this time
The cooling ability of the heating element 21 of the thermal head according to No. 5 is the weakest, and when heat is accumulated in the heating element 21 and the temperature is about to rise, the second on-off valve 35 is opened. At this time, by sucking up the coolant 31 from the two branch pipes 33a, its flow rate increases, and the cooling capacity of the cooling device 25 also increases. When heat further accumulates in the heat generating element 21, the third and fourth on-off valves 35 are sequentially opened to increase the flow rate of the cooling liquid 31, thereby increasing the cooling capacity of the cooling device 25.

In this way, the cooling capacity of the cooling device 25 is controlled by increasing the number of on-off valves 35 that are opened in accordance with the temperature rise due to heat accumulation in the heating element 21, and the temperature around the heating element 21 of the thermal head is controlled. It is possible to maintain the temperature constant, and to perform cooling suitable for the temperature rise of the heating element 21.

Therefore, it is possible to suppress the amount of heat accumulated around the heat generating element as much as possible, to prevent the transfer density from increasing steadily, and to improve printing quality.

In addition, since the cooling effect can be performed without unnecessarily suppressing the temperature rise around the heating element, there is no need to suppress the temperature rise of the heating element more than necessary, thereby impairing the heat generation effect and hindering the transfer operation. It can be prevented.

In addition, there is no need for devices or circuits to suppress temperature rise by controlling the time that current flows to the heating element or its voltage, reducing the cost of the entire device. This is advantageous for high-speed transfer because it does not take more time than necessary.

Furthermore, since the heat dissipation plate 22 supporting the heat generating element has a through hole through which the cooling liquid passes near the heat generating element, the area around the heat generating element can be effectively cooled.

In addition, in the above embodiment, the branch pipe 33 of the irregularly shaped pipe 33
Although the case is shown in which there are four (four) valves a and four on-off valves 35, they do not need to be limited to four (four).

Furthermore, in the above embodiments, a thermal transfer film coated with a heat-soluble printing ink (mainly pigment) was described, but a thermal transfer film coated with a sublimation printing ink (sublimation dye) may also be used. good.

〔effect〕

As explained above, according to the present invention, the cooling capacity of the cooling device is controlled by increasing the number of on-off valves that are opened in response to the temperature rise due to heat accumulation in the heat generating element of the thermal head, and the cooling capacity of the cooling device is controlled. It is possible to perform cooling suitable for the temperature rise of the thermal head, and to maintain the temperature of the heating element of the thermal head constant.

Therefore, it is possible to suppress the amount of heat accumulated around the heating element as much as possible, prevent the transfer density from increasing in a single pattern, and improve print quality.

In addition, since the cooling effect can be performed without unnecessarily suppressing the temperature rise around the heating element, there is no need to suppress the temperature rise of the heating element more than necessary, thereby impairing the heat generation effect and hindering the transfer operation. It can be prevented.

In addition, there is no need for devices or circuits to suppress temperature rise by controlling the time that current flows to the heating element or its voltage, reducing the cost of the entire device. This is advantageous for high-speed transfer because it does not take more time than necessary.

Further, since a through hole through which the cooling liquid passes is formed in the heat sink that supports the heat generating element in the vicinity of the heat generating element, the area around the heat generating element can be effectively cooled.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of a thermal transfer printer device according to the present invention, FIG. 1(a) is a side view of a heating element and a heat sink of a thermal head, and FIG. (a
) is an overall view of the heating element, heat sink, and cooling device of the thermal head; FIG. 2 is a perspective view of the conventional thermal transfer printer shown in -; FIG. FIG. 4 is a perspective view showing another conventional thermal transfer printer device. 21... Heating element 22 of the thermal head...
... Heat radiation plate (heat radiation member) 22a ... Through hole 25 ... Cooling device 26.27 ... Pipe 28 ... Tank 30 ... ... Pump 31 ... Cooling liquid 33 ... Irregular pipe 33a ... Branch pipe 35 ... Opening/closing valve Figure 3 Figure 4 Patent applicant Co., Ltd. Rico -

Claims (1)

[Claims] In a thermal transfer printer device that includes a heating element that heats printing ink and a heat radiating member that supports the heating element and radiates heat stored in the heating element, a cooling liquid is provided in the vicinity of the heating element of the supporting member. A thermal transfer printer device, characterized in that a through hole is formed therethrough, and a cooling device capable of supplying a cooling liquid at a variable flow rate is provided to the through hole.