JP2693265B2 - Manufacturing method of thick film thermal head - Google Patents

Description

The present invention relates to a method for manufacturing a thick film thermal head.

(B) Conventional Technology Generally, in a well-known thick film thermal head, as shown in FIG. 2, a glaze layer 2 is formed on a ceramic substrate 1, and an electrode pattern conductor (common (For electrodes) 3 and electrode pattern conductors (for individual electrodes) 4 are formed, and the end portions of these electrode pattern conductors 3 and 4 are included,
A resistor layer 5 is formed by straddling both the electrode pattern electrodes 3 and 4 and covering the upper surface thereof.
The overcoat glass layer 6 is manufactured by printing and firing so as to cover 4 and the resistor layer 5. In the manufacture of this type of thermal head, the softening point of the overcoat is several tens of degrees Celsius higher than the firing temperature because the surface of the overcoat needs to be smoother due to paper scratches, sticking, etc.
The lower ones are used.

(C) Problems to be Solved by the Invention In the conventional method for manufacturing a thick film thermal head described above,
Since the softening point of the overcoat glass is set lower than the firing temperature, it is difficult to prevent electrochemical corrosion. Here, the electrochemical corrosion is caused by the interaction between the water attached to the head surface due to a concluding remark, the chlorine contained in the paper and the current flowing through the common electrode, and the gold that is the conductor of the lower layer of the overcoat glass is corroded. It is the destruction of breaking the wire. The following table shows the results of tests that accelerated electrochemical corrosion.

As a cause of the electrochemical corrosion, due to the relationship between the firing temperature and the softening point, as shown in FIG. 2, the bubbles 8 exist inside the coated glass 6 and the bubbles 8 start to grow. Since 8 cannot be completely removed, there is a cavity in the overcoat glass 6. If the surface of the overcoat glass 6 is scratched for some reason, it is considered that moisture and chlorine penetrate into the inside of the overcoat glass 6 and reach the conductor through the cavity 8 to corrode.

The present invention has been made in view of the above problems, and an object thereof is to provide a manufacturing method capable of manufacturing a thermal head capable of eliminating bubbles and preventing the occurrence of electrochemical corrosion.

(D) Means and Actions for Solving the Problems A method for manufacturing a thick film thermal head according to the present invention is such that an electrode pattern conductor is formed on an insulating substrate, and a part of the electrode pattern conductor is included to form a resistor layer. In the manufacturing method of covering, covering the resistor layer and the electrode pattern conductor, printing the glass coat layer, and baking the glass coat layer, the glass coat layer is baked at a temperature lower than the softening point of the glass.

According to this method for manufacturing a thick film thermal head, since the overcoat glass is fired at a temperature lower than the temperature at which the glass softens, bubbles inside the glass do not grow. Therefore, a large cavity cannot be formed in the glass. This allows
It becomes difficult for water and chlorine to reach the underlying electrode pattern conductor.

(E) Embodiments The present invention will be described in more detail with reference to embodiments.

FIG. 1 is a sectional view of a thick film thermal head manufactured according to an embodiment of the present invention.

In this thick film thermal head, a glaze layer 2 is formed on an insulating substrate 1 made of ceramic or the like, and an electrode pattern conductor 3 for a common electrode and an electrode pattern conductor 4 for an individual electrode are formed on the upper surface of the glaze layer 2. , The end portions 3a of the electrode pattern conductor 3 for these common electrodes and the end portions 4a of the electrode pattern conductor 4 for individual electrodes are covered,
A strip-shaped resistor layer 5 is formed in a direction orthogonal to the above, and further covers these electrode pattern conductors 3 and 4 and the resistive film layer 5,
An overcode glass layer 6 is formed. The basic structure of this thick film thermal head is not different from the conventional structure.

A feature of the present invention is that glass having a softening point higher than the firing temperature is used as the overcoat glass layer 6, and the electrode pattern conductors 3 and 4 and the resistor layer 5 are covered, printed, and fired. is there.

In this manufacturing method, since the firing temperature is set lower than the softening point, bubbles inside the glass do not grow during firing. Therefore, no cavity is formed in the overcoat glass layer 6, moisture or chlorine does not reach the electrode pattern conductors 3 and 4 from the outside, and electrochemical corrosion is extremely unlikely to occur.

(F) Effect of the Invention According to the present invention, since the overcoat glass layer is fired at a temperature lower than the softening point of the glass when it is fired, the growth of bubbles inside the glass does not start at the time of firing. This has the effect that almost no physical corrosion occurs.

The following table shows the results of the acceleration test when the one having a softening point higher than the firing temperature was used. The best one shows a 5 times higher effect than the conventional product.

[Brief description of the drawings]

FIG. 1 is a sectional view of a thick film thermal head manufactured by implementing the present invention, and FIG. 2 is a sectional view of a thick film thermal head manufactured by a conventional method. 1: Insulating substrate, 2: Glaze layer, 3: Common electrode pattern conductor, 4: Individual electrode pattern conductor, 5: Resistor layer, 6: Overcoat glass layer.

Claims (1)

(57) [Claims] 1. An electrode pattern conductor is formed on an insulating substrate, the electrode pattern conductor is partially covered with a resistor layer, the resistor layer and the electrode pattern conductor are covered, and a glass coat layer is printed. In the method for manufacturing a thick film thermal head, the method for manufacturing a thick film thermal head is characterized in that the glass coating layer is baked at a temperature lower than the softening point of the glass.