JPS6040262A - Manufacture of thermal recording head - Google Patents

Abstract

PURPOSE:To make a high density thermal recording head free from disconnection even when an underglass is laminated only on a part of a substrate by forming two layers of conductive layers in an area the thickest in a staircase- shaped underglass layer. CONSTITUTION:A staircase-shaped underglass layer 5 is formed on a necessary part of an electrical insulation substrate 1 with a better heat conductivity and a first conductive layer 6 is provided in the thickest area W1. Then, when a second conductor layer 5 is provided covering the substrate 1 together with the layer 5, the layers 6 and 5 are laminated on the area W1 becoming thinner in the layer 5 to prevent the generation of a pinhole or the like. This enables the making of a high density thermal recording head free from the possibility of disconnection simply and accurately even when the underglass is laminated only on a part of the substrate.

Description

Detailed Description of the Invention (Not applicable! I!+) The present invention is a thick film thermal recording head for converting electric pulse No. 113 of facsimile printers etc. into heat and performing tC thermal printing on thermal recording paper etc. Start with the manufacturing method.

(Prior Art) A conventional thick film thermal recording head was fabricated as follows. First, as shown in FIG. 1, a rectangular substrate 1 made of alumina or the like with good thermal conductivity is prepared.
On top and in the center thereof, an under glass 2 as a heat storage m is laminated by screen printing or the like in parallel to the longitudinal direction of the substrate. Next, the conductor 3 is screen printed and burned on the entire surface. Thereafter, photoresist is applied and conductor patterning is performed to form alternating lead portions 3' as shown in FIG. 2I.

In this conventional device, a stepped portion is formed in the under glass layer 2, for example, in three steps as shown in FIG. area, then the thickest area is labeled area B, and the thinner area is labeled area C. Then, the area on the under glass layer 2 is
The narrow tips of the alternating lead portions 3', which contribute to heat generation due to patterning of the ζ conductor 3, were formed in area A, as shown in FIG.

Such a conventional device in which the under glass 2 is laminated only on a portion of the substrate 1 has the advantage that the amount of the under glass 2 used is small and is economical.

However, since the A area is raised, when the conductor 3 is printed, the conductor layer on the A area of the underglass 2 becomes thinner than the conductor layer in other areas, and pinholes are likely to occur. For this reason, when alternating IJ-dot portions 3' as shown in FIG. 2 are formed by pattern Jung, there is a drawback that the ends of these portions are thin and easily break. In addition, when trying to thicken the conductor layer in area A (second), the entire surface of the conductor layer had to be made uniformly thick, and conductor 3 containing Au was frequently required, which had the disadvantage of being uneconomical. .

On the other hand, as the density of the alternating lead portions increases and the width of each IJ-de becomes narrower, the under glass 2 is placed over the entire surface of the substrate 1.
A version with a flat under glass layer has been released. This conventional device has the advantage that since the conductor 3 can be made to have a uniform thickness by screen printing, the occurrence of pinholes as described above can be reduced. However, the following drawbacks occur.

(1) Since the coating is applied to unnecessary parts of the underglass, the amount of underglass used increases, making it uneconomical.

(2) P gg between the alumina substrate and the under glass
Due to the difference in elongation, the substrate warps during firing and cooling.

(Objective) The object of the present invention is to manufacture a high-density thermal recording head without the risk of wire breakage while maintaining efficiency and accuracy by laminating an under glass layer only on a part of the substrate. This is to provide a way to do so.

(Summary) Features of the present invention (e) A step-like underglass layer is formed in the longitudinal direction on an electrically insulating substrate with good thermal conductivity, and then the step-like underglass layer is formed in the longitudinal direction. The first conductor layer is provided at least in the thickest region, and the second conductor layer is further formed on the substrate, the underglass layer, and the first conductor layer.

(Example) The present invention will be explained below by way of examples.

(1) As shown in FIG. 3(a), an under glass layer 5 is formed in a stepped manner on a substrate 1 made of alumina or the like so that the maximum thickness H is 20 to 60 μm. Hakusuwara, the thickness of the area W, , W, , W in the figure is the thickness of WI>) ■2
It is formed by repeating printing and firing so that the thickness is greater than Ws, and the layers are laminated. Although the number of steps is shown as three, the maximum thickness H is 20 to 60/! To rub it so that it becomes lnl lζ, you can use any of the 2nd to 4th steps.

(2) Next, a conductor (A
u) 20% of the paste (TR-t14c manufactured by Tanaka Mysey)
It is diluted with a diluting solution so that it becomes % by weight, and using the same screen printing plate as IfFSW, it is screen printed so as to overlap it on the under glass having a width of W. Thereafter, it was fired to obtain @1 conductor layer 6 having a film thickness of 1.6 μm.

(3) Furthermore, the conductor (A++) paste was screen printed on the entire surface without dilution, to obtain a second conductor R7 as shown in FIG. 3(c).

(4) The first and second conductor layers 6 and 7 were etched into a desired pattern to obtain alternating leads as shown in FIG. 2, for example.

The first and second conductor layers 6, 7 made as above
When the film jI7 was measured, the thickness E on the alumina substrate was 4.511 m.
7.Dl; t 4.5-5.011 m. Moreover, some pinholes were observed at a thickness F lj of 3.0 μm on the width W2 region.

The pattern of the thermal recording head according to this embodiment made as described above is of an alternating lead type as shown in FIG. is dense) W becomes 1/2. If you change the line width of the alternating lead part i; t tV,
area, and the W2 area contains its t”1.2 of eA.
Double the lead part is made. However, some pinholes in the conductor layer that occur in the -C(W) region do not pose a problem.

In the above embodiment, the first conductor layer 6 was formed only in the W0 region, but it may be formed in both the W and tW regions, or it may be formed in the entire W, -W region. There is no problem.

(Effects) As is clear from the above description, the following effects are achieved by the present invention.

(1) Since the conductor film in the heat generating part (highest density part) can be made into a dense film without any bottle balls, it is possible to manufacture a high density 1f (1f) thermal recording head without defects.

(2) Since the under glass can be used only in the heat generating part, the amount of glass paste used can be reduced.

(3) In addition, compared to the JQ case in which an under glass layer was printed and fired on the entire surface of the J11ζ board, the above-mentioned results were shown in No. 1 (the board warpage was smaller, and more accurate Bakun Yung and uniform printing were possible).

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of the pattern Jung f'lfl of the heat generating part of a conventional thick film thermal recording head, Fig. 2 is a plan view after patterning of the conductor in Fig. 1, and No. 3 P'A (11t
, (b). FIG. 3 is a cross-sectional view showing the manufacturing process of an embodiment of the kH14'invention.;A=Plate, 2, 5 - Under glass, 3... Conductor, 3' Alternate lead part, 6 - First conductor layer, 7
・Second conductor layer 11p Michi Hiraki (non-human) Figure 1 Figure 2 q' 1 Figure 3 (a)

Claims (1)

[Claims] (J) A step of forming a stepped underglass layer in the longitudinal direction on an electrically insulating substrate with good thermal conductivity, and a first conductor in at least the thickest region of the stepped underglass layer. 7. A method for manufacturing a thermal recording head, comprising the steps of: providing a layer; and forming a second conductive layer on the base of the +c nQ substrate, the underglass layer, and the first conductive layer.