JPH08216443A - Thermal head - Google Patents

Abstract

PURPOSE: To increase the heat efficiency of a thermal head by forming a space in a section corresponding to a heater across a base on a base component of a thermal head with a heat dissipation means. CONSTITUTION: A ceramic base 4 is laminated on a base component 2 composed of aluminum material through a bonding agent layer 3 of a thermal head 1, on which a heater section H is provided. A plane glace section 5 is formed on the base 4 by the heater section H, and a partially glace layer 6 is formed on the end of the glace section, over which a plurality of heaters 7 are formed in the vertical direction and a signal electrode 8 and a common electrode 9 are connected thereon to form a wear-resistant layer 10 covering the vicinity of the upper faces of the heaters 7. A space 11 is formed by forming a recessed channel 2a on a section corresponding to the heater section H across the base 4 on the base component 2. As a result, thermal conductivity to the heater section are lowered and the regenerating properties in the vicinity of heaters is improved, and the transfer by the comparatively small amount of heat application can be carried out at the time of transfer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal head in a sublimation transfer recording device or the like.

[0002]

2. Description of the Related Art In a thermal transfer recording apparatus such as a sublimation transfer recording apparatus, a ceramic substrate is provided on a base member as a heat dissipation member made of an aluminum material, and a heater and a head driver for driving the heater are provided on the ceramic substrate. With a thermal head, the image receiving paper and sublimation ink sheet are sandwiched between the thermal head and the platen roller, and the heater of the thermal head is driven according to the image data to transfer the ink from the sublimation ink sheet to the image receiving paper. Then, an image is formed.

[0003]

The ink sheets used in the sublimation transfer recording apparatus include a multi-time ink sheet that can be used multiple times and a one-time ink sheet that can be used only once. Here, when the multi-time ink sheet is used, 1.2 to 1.3 times the transfer energy is required as compared with the case where the one-time ink sheet is used.

That is, in the multi-time ink sheet, the base layer forming the ink layer is thicker than in the one-time ink sheet. For example, in order to apply high energy, PET used in the base layer of the one-time ink sheet is changed to polyamide resin, and the thickness thereof is generally 6 μm. In addition, the thickness of the ink layer is about 7 μm, which is thicker than 2 μm of the one-time ink sheet, in order to obtain multiplicity. Therefore, in the case of sublimation transfer in which dye is transferred with thermal diffusion, high thermal energy must be injected. Therefore, it is required to improve the thermal efficiency of the thermal head.

The present invention has been made in view of the above points, and an object thereof is to improve the thermal efficiency of a thermal head.

[0006]

In order to solve the above-mentioned problems, the thermal head according to claim 1 has a heater formed on a substrate provided on a base member, and radiates heat to the base member by the heater or the like. In a thermal head provided with a heat dissipation means, a space is formed in the base member at a portion corresponding to the heater with the substrate interposed therebetween.

A thermal head according to a second aspect is the thermal head according to the first aspect, wherein the substrate is provided with a temperature detecting means for detecting a temperature.

According to a third aspect of the present invention, there is provided a thermal head according to the first or second aspect, wherein an air flow guide member for guiding a wind flow to a head driver for driving the heater, and the head through the air flow guide member. And a blowing means for blowing air to the driver.

[0009]

In the thermal head according to the present invention, since the gap is formed in the portion corresponding to the heater with the substrate of the base member sandwiched, the conductivity of heat from the heater to the heat radiating means is deteriorated, and the heat storage property in the vicinity of the heater is reduced. By improving the temperature and raising the temperature to a constant temperature value by this heat storage, the transfer can be performed with a relatively small amount of heat applied during the actual transfer, and the thermal efficiency is improved.

According to a second aspect of the present invention, in the thermal head according to the first aspect, the temperature detecting means for detecting the temperature is provided on the substrate, so that the temperature in the vicinity of the heater can be detected at high speed and with high accuracy.

According to a third aspect of the present invention, there is provided a thermal head according to the first or second aspect, wherein an air flow guide member for guiding a flow of air to a head driver for driving a heater, and a head driver through the air flow guide member. Since the blowing means for blowing air is provided, it is possible to suppress the temperature rise of the head driver due to heat conduction from the heater section to the head driver.

[0012]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is an enlarged cross-sectional view of a main part of a thermal head to which the present invention is applied, and FIG. 2 is a diagram for explaining the operation of FIG. In this thermal head 1, a ceramic substrate 4 is laminated on a base member 2 made of an aluminum material with an adhesive layer 3 interposed therebetween, and a heater portion H is formed on the ceramic substrate 4. In this heater portion H, a plane grace portion 5 is formed on a ceramic substrate 4, a partial grace layer 6 is formed at the tip of the plane grace layer 5, and a plurality of heaters 7 are formed on the partial grace layer 6 on the paper surface. It is made up of multiple pieces in the vertical direction,
A signal electrode 8 and a common electrode 9 are connected to the heater 7, and a wear resistant layer 10 covering the vicinity of the upper surface of the heater 7 is formed.

A void 11 is formed in the base member 2 by forming a concave groove 2a in a portion corresponding to the heater 7 (heater portion H) with the ceramic substrate 3 interposed therebetween. The voids 11 are formed in the direction in which the heaters 7 are arranged, and for example, a groove width of approximately 1 to 1.5 mm and a depth of approximately 1 mm are sufficient. The voids 11 are formed to be as symmetrical as possible with respect to the direction (heater line) orthogonal to the arrangement direction of the heaters 7.

In the thermal head 1 thus configured, recording is performed by applying a driving pulse to the signal electrode 8 to energize the heater 7 to heat the sublimable ink sheet and transfer the ink to the image receiving paper. To do. Here, the relationship between the time and the heater surface temperature was measured while applying the drive pulse in the case where the void 11 was formed in the base member 2 (the present invention) and in the case where the void 11 was not formed in the base member 2 (conventional example). When the voids 11 are formed in the base member 2, the change shown by the solid line a in FIG.
When the void 11 is not formed in the base member 2, the change shown by the alternate long and short dash line b is shown in FIG.

In this case, assuming that the heater surface temperature that gives the energy necessary for diffusing and transferring the sublimable ink of the ink sheet is the transfer temperature T0, as shown in FIG. 2, the driving pulse is applied and then the heater is applied. The transfer time until the surface temperature of 7 reaches the transfer temperature T0 is
The transfer time ta when the space 11 is formed in the base member 2 is shorter than the transfer time tb when the space 11 is not formed in the base member 2 (ta <tb).

By forming the space 11 in the base member 2 in this way, the rise time of the heater 7 up to the transfer temperature T0 is shortened and the temperature rise gradient is increased. This is because the heat generated by the heater 7 is normally conducted from the ceramic substrate 3 through the base member 2 to the heat radiating means such as a heat radiating plate and is radiated. This is because the thermal conductivity to 2 is reduced and heat is accumulated in the vicinity of the heater 7.

Therefore, the heater 7 is controlled by managing this heat storage.
By preheating the temperature in the vicinity of a certain temperature to a constant temperature, for example, applying a low-level pulse in advance to perform preheating, transfer can be performed by giving a relatively small amount of heat during actual printing. It becomes possible and the thermal efficiency is improved.

Next, FIG. 3 is an enlarged sectional view of a main part of a thermal head showing another embodiment of the present invention, and FIG. 4 is a block diagram including a control system of the thermal head of FIG. The thermal head 1 includes a heater 7 for a ceramic substrate 4 in a space 11.
A thermistor 12, which is a temperature detecting means for detecting the temperature in the vicinity of the heater 7, is provided on the surface opposite to the surface forming the. As shown in FIG. 4, a plurality of thermistors 12 are arranged at equal intervals in the direction in which the heaters 7 are arranged, but they may be arranged at one central position.

The control system of the thermal head 1 includes a control unit 15 including a microcomputer or the like, which controls the overall operation, and a sensor amplifier 16 which amplifies a detection signal of each thermistor 12 and outputs the amplified detection signal to the control unit 15. Mounted on the thermal head 1 to drive (power) each heater 7.
A head driver 17 and a head controller 18 that controls the head driver 17 according to information from the control unit 15.
And the like, and power is supplied to the control unit 15, the thermal head 1 and the like by a power source 19.

In the thus constructed thermal head and its control system, the control unit 15 detects the temperature in the vicinity of the heater 7 based on the detection signal from each thermistor 12,
The head controller 1 calculates an average temperature change of a plurality of detected temperatures detected, and based on the calculated average temperature change.
The energy applied by the heater 7 is corrected by controlling the pulse width or the number of pulses of the drive pulse given to the heater 7 via the head driver 17 by controlling the pulse width 8. Note that this correction can be performed using a correction table or the like for average temperature changes. It is also possible to control the voltage of the power supply 19 applied to the thermal head 1.

By doing so, the temperature change by the heater 7 can be detected more directly than in the case where the thermistor 12 is provided on the heat dissipation board or the PCB board on which the head driver is mounted to detect the environmental temperature. As a result, the temperature change can be detected at high speed and with high accuracy, and the control accuracy of the thermal head is improved.

Next, FIG. 5 is a schematic view including a head driver of the thermal head according to the present invention, FIG. 6 is a schematic view of a main part of a recording apparatus equipped with the thermal head of FIG. 5, and FIG. FIG. A PCB board 21 is attached to the rear side of the thermal head 1 on the base member 2 of the thermal head 1, and a head driver 17 is arranged on the PCB board 21. 1)) via a bonding wire 22 and also to the PCB board 21 via a bonding wire 23, and a connector 24 is attached to the PCB board 21.

The recording apparatus equipped with this thermal head 1 has an ink sheet 25 between it and the thermal head 1 which is pressed by a head pressing mechanism 24 as shown in FIG.
And the platen roller 2 for transporting the image receiving paper 26 between them.
7 is provided. The ink sheet 25 is wound around a supply / rewinding roll 28, passed between the thermal head 1 and the platen roller 27, and wound up by a winding roll 29 to be conveyed. Further, the image receiving paper 26 is conveyed by the drive roller 30.

Here, the base member 2 of the thermal head 1
The air flow guide members 31 and 32 for guiding the air flow to the head driver 17 are provided on the rear side of the fan driver 17, and the fan 34, which is a blowing means for flowing the air in the air passage 33 formed by these air flow guide members 31 and 32, is provided. The wind flow guide member 3
It is provided between 1 and 32. The fan 34 is adapted to take in air from both sides (both sides in the heater line direction) of the thermal head 1 into the head driver 17 and rotate the air in a direction of discharging the air rearward. Although the fan 34 is dedicated to the head driver 17, it is also possible, for example, to branch the wind of the fan for cooling the heat dissipation plate and guide it to the head driver 17 with a guide member.

In the thermal head 1 thus constructed, the fan 34 is rotationally driven to take in air from both sides as shown by the white arrow in FIG. 7 and flow backward through the head driver 17. Since the temperature rise of the head driver 17 is suppressed by being blown to the head driver 17, even if the heat from the heater 7 is conducted to the head driver 17, it is possible to keep the ambient environment below the guaranteed temperature (usually 70 ° C.). become.

[0026]

As described above, according to the thermal head of the first aspect, since the gap is formed in the portion corresponding to the heater with the substrate of the base member being sandwiched, the conductivity of heat by the heater to the heat radiating means is improved. It becomes worse and the heat storage property in the vicinity of the heater is improved. By raising the temperature to a constant temperature value by this heat storage heat, it becomes possible to transfer with a relatively small amount of applied heat at the time of actual transfer, and thermal efficiency is improved. .

According to the thermal head of the second aspect, since the temperature detecting means for detecting the temperature is provided on the substrate in the thermal head of the first aspect, the temperature in the vicinity of the heater can be detected at high speed and with high accuracy. As a result, it becomes possible to control the temperature of the heater with high accuracy.

According to the thermal head of claim 3, in the thermal head of claim 1 or 2, an air flow guide member for guiding the air flow to the head driver for driving the heater, and the head via the air flow guide member. Since the blowing means for blowing air to the driver is provided, it is possible to suppress the temperature rise of the head driver due to heat conduction from the heater section to the head driver, maintain the guaranteed temperature of the head driver, and continue at high speed. Printing is possible.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view of a main part of a thermal head to which the present invention is applied.

FIG. 2 is a diagram for explaining the operation of FIG.

FIG. 3 is an enlarged sectional view of a main part of a thermal head showing another embodiment of the present invention.

FIG. 4 is a block diagram including a control system of the thermal head of FIG.

FIG. 5 is a schematic diagram including a head driver of a thermal head according to the present invention.

FIG. 6 is a configuration diagram of main parts of a recording apparatus including the thermal head of FIG.

7 is an explanatory diagram for explaining the operation of FIG.

[Explanation of symbols]

1 ... Thermal head, 2 ... Base member, 2a ... Recessed groove, 4
... ceramic substrate, 5 ... plane grace part, 6 ... partial grace part, 7 ... heater, 8 ... signal electrode, 9 ... common electrode, 1
0 ... Wear resistant layer, 11 ... Void, 12 ... Thermistor, 17 ...
Head driver, 31.32 ... Air flow guide plate, 34 ... Fan, H ... Heater section.

Claims (3)

[Claims] 1. A thermal head in which a heater is formed on a substrate provided on a base member, and heat dissipation means for radiating heat from the heater or the like is provided on the base member, and the substrate is sandwiched by the base member. A thermal head characterized in that a void is formed in a portion corresponding to the heater. 2. The thermal head according to claim 1, wherein the substrate is provided with temperature detecting means for detecting a temperature near the heater. 3. The thermal head according to claim 1, wherein an air flow guide member for guiding a flow of air to a head driver that drives the heater, and an air blower for blowing air to the head driver via the air flow guide member. A thermal head characterized by having means.