JPS6198565A - Thermal head unit - Google Patents

Abstract

PURPOSE:To improve rising characteristics at the time of heating and falling characteristics at the time of heat emission by using a shape memory alloy as a heat sink material which supports a thermal head, and by forming heat dissipating fins as a heat sink. CONSTITUTION:A heat sink 5 is formed with a shape memory alloy, and at the same time heat dissipating fins 5b are installed on the reverse side (opposite of a thermal head 3) of the heat sink base 5a, and in the extension of the moving direction of a carriage 4. In a construction of the thermal head unit, in which a heat sink 5 is used as stated, in case of supercooling of the thermal head 3, and if the heat dissipating fins 5b are left inclined, the rising characteristics at the time of heating are improved. And if the thermal head 3 is overheated, by making the heat dissipating fins 5b stand uprightly, cooling effect is accelerated, and falling characteristics at the time of heat dissipation may be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to the structure of a thermal head unit in which a thermal head having a plurality of heating elements (resistive elements) on a press-contact printing surface is fixed to a heat sink.

[Prior art]

Thermal recording devices such as Thermal/Link are divided into two types: thermal transfer type, which uses plain paper and prints through in-clean, and thermal paper type, which uses thermal paper and prints by heating it to develop color. = The thermal head used in these thermal recording devices has a plurality of (for example, 24) heating elements (heating elements) arranged vertically (usually in a single vertical line) on its pressure contact surface. During the printing operation, desired characters, figures, etc. are recorded by moving the printing head unit while driving each heating element based on a printing/arm turn signal.

This type of thermal head generally has a structure in which the heating elements are mounted in a predetermined arrangement on the surface of a ceramic substrate with excellent heat dissipation.More specifically, for example, a glass It has a structure in which a heating element and a layer of power supply lead wires connected to each heating element are formed on top of the glaze layer, which is then covered with a protective layer with excellent wear resistance. are doing.

However, in conventional thermal storage devices that use such thermal heads, it takes a certain amount of time for the temperature to rise and fall when the heating element is heated (on) and dissipated (off), and the cooling section (dot printing There has been a problem in that the printing speed cannot be increased very much in order to make clear the difference between the heated part (the part where dot printing is not performed) and the heating part (the part where dot printing is performed) and to perform clear recording.

In other words, when the thermal head is properly cooled, the temperature rises during heating becomes slower, resulting in faint, unclear, or unrecordable prints, while when the thermal head is overheated, the temperature decreases during heat dissipation becomes slower. Draws and becomes blurry or illegible. Therefore, in order to perform high-speed printing, it is necessary to improve both the rise characteristics when the temperature rises when the thermal head is overcooled and the fall characteristics when the temperature decreases when the thermal head is overheated. There is a strong correlation that if the start-up time during heating is improved, the second decreases, and if the start-up time during heating is improved, the heat dissipation decreases, making it unsuitable for high-speed printing.

On the other hand, it is possible to solve the above drawback by detecting the temperature of the thermal head and controlling the drive current of the printing heating element based on this detection signal, but in such a structure, the detection device control circuit etc. This has the disadvantage that the structure is complicated and the cost is high.

〔the purpose〕

The object of the present invention has been made in view of the above-mentioned drawbacks.
It has a simple structure, can be manufactured at low cost, and has a startup time of 9 when heated.
An object of the present invention is to provide a thermal head unit that can improve characteristics and fall characteristics during heat radiation.

[Summary]

The present invention, Fl; 1, uses a shape memory alloy as the material of the heat sink that supports the thermal head, and forms heat dissipation fins on the heat sink, and adjusts the heat dissipation effect by changing the shape of the heat sink fins according to the temperature. The purpose of the present invention is to achieve the above objectives.

〔Example〕

Hereinafter, the present invention will be explained in detail using embodiments shown in the drawings.

In FIG. 1, the reference numeral 1 indicates a thermal head unit, and as shown in FIG. It is composed of thermal spatulas P3 arranged in a vertical line and made of ceramic substrates with excellent heat dissipation properties, and a heat sink 5 fixed to the back side of the thermal head 3 and supported by gears 4. In addition, the illustration d
Although omitted, individual lead wires and a common lead wire are connected to each of the heating elements 2, and the desired heat generation is achieved by supplying current through these lead wires in accordance with the printed Δ turn signal. It is configured to drive the body.

On the other hand, the carriage 4 is slidably attached to a guide shaft 7, and the carriage 4 is fixed in the middle of the belt 7. Further, the belt 7 is formed to be endless, and is stretched between an idler pulley 8 and a drive pulley 9 on its left and right sides. The drive pulley 9 is connected to a stepping motor 10, and its rotation causes the belt 7 to run, and the carriage 4 and thermal head unit 1 to move along the guide shaft 6, thereby printing on the recording paper 11. It is said that

In this embodiment, the heat sink 5t is formed of a shape memory alloy, and the heat sink 5t is formed of a shape memory alloy, and is provided extending in the moving direction of the caliper 4 as shown in FIGS. It is characterized by the structure in which the heat dissipation fins 5b are provided. Shape memory alloy refers to an alloy that has mechanical memory ability, and there are two types of this alloy: Ni-Ti alloy and (!u-Zn-Aj alloy). As shown, the heat dissipation fins 5b are set so as to stand vertically with respect to the heat sink body 5a at a temperature higher than a certain set temperature.Next, the heat sink 5t6 is cooled to a set temperature or lower, and then As shown in Fig. 4, the radiation fins 5b are tilted with respect to the heat sink main body 5a to form a good shape.In such a heat sink 5, when the heat sink 5 is heated again to the set temperature or higher, the radiation fins 5b are It will return to its original shape as shown in Figure 3.

Therefore, in the structure of a thermal head unit using such a heat sink 5, by changing the shape of the radiation fins 5b when the thermal head 3 is properly cooled and when it is overheated, that is, when the thermal head 3 is properly cooled, the heat radiation is improved. By keeping the shape of the fin 5b in an inclined state as shown in Fig. 4, during heating □
By improving the rising characteristic of the thermal head 3 and by setting the shape of the heat dissipating fin 5b in an upright state as shown in FIG. 3 when the thermal head 3 is overheated, the cooling effect is promoted. Characteristics can be improved. By providing the radiation fins 5b in this way, it is now possible to satisfy both the 9 characteristics of the rise during heating and the characteristics of fall during heat radiation, so the temperature of the heating element 2 is always maintained at an appropriate level. can,
Clear, high-speed printing is possible. In this embodiment, the shape of the heat sink 5 is set such that the shape of the heat sink 7 changes automatically when the temperature reaches the constant temperature, so there is no need to separately provide a detection device, a control circuit, etc., and it is easy to use. It has a simple structure and can be manufactured at low cost.

〔effect〕

As is clear from the above description, according to the thermal heat sink unit according to the present invention, the material of the heat sink is a shape memory alloy, the heat sink is formed with radiation fins, and the shape of the fins of the heat sink is changed depending on the temperature. Since the structure is configured to adjust the heat dissipation effect by changing the heat dissipation effect, it has a simple structure and can be manufactured at low cost.Moreover, the temperature change of the thermal head can be maintained appropriately, making it possible to perform clear high-speed printing. It has excellent effects.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a thermal recording device equipped with a thermal head unit according to the present invention, FIG. 2 is an enlarged front view of the thermal head unit, and FIG. 3 is an explanatory diagram of the operation of the fourth lamp thermal head unit. It is. 1... thermal head), 2-... heating element, 3
...Thermal head, 5-・Heat sink, 5b・-
heat dissipation fins.

Claims (1)

[Claims] In a thermal head unit consisting of a thermal head having a resistor element and a heat sink supporting the thermal head, the material of the heat sink is a shape memory alloy, heat radiation fins are formed on the heat sink, and the fins of the heat sink are changed depending on the temperature. A thermal head unit that adjusts the heat radiation effect by changing the shape of the head unit.