JPH0334864A - Preparation of thermal head - Google Patents

Abstract

PURPOSE:To control the resistance values of heating resistors in both up and down directions by forming a heating resistor pattern based on ruthenium oxide to the surface of the glass film layer on the surface of a substrate to irradiate the same with laser beam. CONSTITUTION:A glass film layer is formed to the surface of a substrate 1 and a common electrode 2 and individual electrodes 31-3n are formed on the surface of the substrate 1 and a heating resistor group 4 is formed so as to be electrically connected to the common electrode 2 and the individual electrodes 31-3n using a material based on ruthenium oxide. A thermal head S is arranged on an X-Y table 5 and the X-Y table 5 is controlled by a microcomputer 6. A resistance measuring apparatus 7 is connected to the microcomputer 6 and one probe 8 is connected to the common electrode 2 of the thermal head 2 and the other probe 8' is connected to the individual electrodes 31-3n. The microcomputer 6 controls the pulse laser beam outputted from an oscillation apparatus 9 and the laser beam is converged to predetermined luminous flux by a lens 10. When the individual electrodes 31-3n are irradiated with pulse laser beam, the resistance values thereof can be changed in both of directions of increasing and decreasing said resistance values.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a multi-head used in facsimiles and the like.

(Conventional technology) As a prior art related to the present invention, Japanese Unexamined Patent Application Publication No. 6(1998) (1) There is something described in 19266653 Kokaku.

This conventional technique will now be explained. Thermal pads used in facsimiles and the like are classified into thick-film types and thin-film types based on differences in manufacturing processes. Conventionally used heating resistors are known to have a voltage range within which dielectric breakdown does not occur even if a voltage higher than that under normal usage conditions is applied. Thick-film thermal heads have a problem in that the resistance value of the heating resistor varies widely, resulting in poor print quality. In order to solve this problem, a method has been known in which the resistance value of the heating resistor is controlled by applying a voltage. In the prior art described above, a method was adopted in which a pulse voltage was applied in order to control the resistance value of the heating resistor of a thick film type thermal head within a predetermined value.

(Problem to be Solved by the Invention) However, with this prior art, the resistance value of the heating resistor can only be controlled in the direction in which the resistance value decreases, but cannot be controlled in the direction in which the resistance value increases. could not.

In addition, in order to control the resistance value of the heating resistor by applying a pulse voltage (L), it is necessary to apply the pulse voltage to the electrode connected to the heating resistor, so there are many variations in the individual resistance values. The manufacturing process for the product required an extremely large amount of time.

A technical problem of the present invention is to enable control of the resistance value of a heat generating resistor in both upward and downward directions.

(Means for solving the problem) The technical means taken to solve the technical problem described in J.2 is to form a glass thin film layer on the surface of a substrate made of an insulating material,
irradiating the heating resistor pattern with a laser beam in a thermal head having a heating resistor Bakun mainly composed of ruthenium oxide formed on the surface of the glass thin film layer;
That's true.

(Function) By taking such technical measures, it has become possible to accurately control the resistance value of the heating resistor both in the upper and lower directions.

(Example) Below is an example (3) in which the technical means of the present invention are implemented. explain about.

FIG.
FIG. In FIG. 1, 1 is an insulating substrate made of, for example, alumina, and 2 is a common electrode formed on the substrate 1. In FIG. This common electrode 2 is formed over the entire surface of the substrate by photoetching. The common electrode 2 has a plurality of protruding electrode portions 2a. The individual electrodes 3. are inserted into the gaps between the electrode parts 2a of the common electrode 2. To-3
, are formed on one surface of the substrate. In this way, a common electrode 2 and a plurality of individual electrodes 2a are formed on one surface of the substrate. 4 is a common electrode 2 on an insulating substrate 1
The portion between the electrode portions 2a of the protrusions is a heating resistor group each formed of a 1-bit heating resistor 4a. The resistance value of each heating resistor 4a thus formed is controlled to a predetermined resistance value by application of pulsed laser light.

Next, a method for manufacturing the thermal head will be explained.

First, a glass thin film layer (brace layer) made of a glass material is formed on one surface (4) of a substrate mainly made of alumina. Next, a common electrode 2 and individual electrodes 3 to 3 . are formed on the surface of the substrate 1 by photoetching. , form.

Similarly, a heat generating resistor group 4 is placed on the common electrode 2 on the substrate 1.
, and are electrically connected to the individual electrodes 3° to 3o. The line width of the heating resistor group 4 is set to approximately 200 μm.

The heating resistor 4 is made of a material mainly composed of ruthenium dioxide (RuO2).

FIG. 2 shows a block diagram of the apparatus used in the present invention. The thermal head S is controlled by a stepping motor.
It is installed on the y-table 5 and can be freely moved on a two-dimensional virtual coordinate plane. X-Y table 5
is controlled by a microcomputer 6, and the thermal head S can be set at any position by inputting numerical values, for example. A resistance measuring device 7 is connected to the microcomputer 6. One of the probes 8 of the resistance measuring device 7 is connected to the common electrode 2 of the thermal head S,
The other probe 8° is connected to individual electrodes 3° (5) to 31. 9 is laser light oscillation 'A'
flZ, and this oscillation device 9 is controlled by a microcomputer 6. The microcomputer 6 controls various conditions such as the output timing of the pulsed laser light outputted from the oscillation device 9, or the oscillation time.

The laser beam output from the oscillation device 9 is converged into a predetermined beam by a lens 10. The lens 10 converges the light into a spot light having a diameter of 100 μm or less, for example. still,
The laser beam is attenuated between the oscillation device 9 and the thermal head S by known means to an energy density of 100 mW/ant or less.

FIG. 3 is a characteristic diagram showing the relationship between the output of the pulsed laser and the change in resistance value of the heating resistor.

When the aforementioned individual electrodes 31 to 3° are irradiated with pulsed laser light, the resistance value can be changed both in the direction of increasing/crossing the resistance value (+) and in the direction of decreasing it (-). The change in resistance value is determined by the upper limit Rffllllll shown in the diagram.
'The lower limit is varied within the range of R1,7. The output intensity of the laser beam is P. is the upper limit. If this upper limit (6) is exceeded, dielectric breakdown will occur in the heating resistor 4A material, making it impossible to control the resistance value, so it is important that the output of the laser beam does not exceed this range. It is.

〔Effect of the invention〕

As explained above, in the present invention, C is a pulsed laser beam.
By irradiating the heating resistor with light, the resistance value can be set to ibl fac+yield 1sj both in the direction of increasing or decreasing the resistance value, so that a high quality natural head can be provided. Furthermore, since the resistance value is controlled while measuring the resistance value, the resistance value can be set with high precision.

Figure 1 is a partial front view of a thermal head representing an embodiment of the present invention, Figure 2 is a block diagram of the device used in the present invention, and Figure 3 is a pulse laser It is a characteristic diagram showing the relationship between the output of - and the resistance value change of the heating resistor.

Substrate...1, (7) Heat generating resistor/ 4, Thermal head 0

Claims (2)

[Claims] (1) A thermal head in which a glass thin film layer is formed on the surface of a substrate made of an insulating material, and a heat generating resistor pattern mainly made of ruthenium oxide is formed on the surface of the glass thin film layer. A method for manufacturing a thermal head characterized by irradiating it with laser light. (2) The method of manufacturing a thermal head according to claim 1, wherein the resistance value of the heating resistor pattern is constantly measured during irradiation with the laser beam.