JPH0717071B2 - Thermal head and manufacturing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention is a combination of a plurality of thermal head substrates
The present invention relates to a thermal head as a body and a manufacturing method thereof.

(B) Conventional Technology In recent years, a large thermal head has been required for the purpose of using it in a plotter or the like. This large thermal head has 1
Although it is most preferable that the thermal head is composed of a single substrate, it is currently practiced to join a plurality of thermal head substrates to manufacture a large thermal head due to the manufacturing facility.

7 and 8 show two thermal head substrates 1
A thermal head 11 constructed by joining 2 and 12 is shown. The thermal head substrate 12 is attached to an independent sub-radiating plate (iron or aluminum) 13 with an adhesive agent 14. Each sub-radiating plate 13, 13 is fixed to the main radiating plate 15 and A body thermal head 11 is constructed.

The adhesive 14 for bonding the thermal head substrate 12 and the sub heat dissipation plate 13 is applied only to the center side. This is because the thermal expansion coefficients of the thermal head substrate 12 and the sub heat dissipation plate 13 are different from each other, and the thermal head substrate 12 freely expands laterally regardless of the expansion of the sub heat dissipation plate 13. If the thermal head substrate 12 and the sub heat dissipation plate 13 are pasted on the entire surface, the thermal head substrate is repeatedly expanded and contracted.
12 is cracked.

(C) Problem to be Solved by the Invention In the above-mentioned conventional thermal head, it is preferable that the number of thermal head substrates to be spliced is two. It becomes impossible. To solve this problem,
If a supporting substrate made of a material having the same coefficient of thermal expansion as the material forming the thermal head substrate (usually ceramic is used), for example ceramic, is prepared and the thermal head substrate is fixed on this supporting substrate, thermal expansion There is no need to consider the difference.

However, since the plate thickness accuracy of the ceramic plate used for the thermal head substrate and the supporting substrate is not so high, the height of the surface of the thermal head substrate becomes uneven, and the printing quality deteriorates due to unevenness around the platen. I will end up.

The present invention has been made in view of the above, and an object of the present invention is to provide a thermal head in which it is not necessary to consider the coefficient of thermal expansion, and the heights of the surfaces of the joined thermal head substrates are uniform, and a manufacturing method thereof.

(D) Means and Actions for Solving the Problems In order to solve the above problems, the thermal head according to the first aspect of the invention has a layer thickness on a supporting substrate having the same coefficient of thermal expansion as the thermal head substrate, using a thickness gauge. With the adjusted adhesive layer of, multiple thermal head substrates are attached side by side,
The height of the surface of each thermal head substrate is made uniform.

A second invention is a method for manufacturing the thermal head, wherein the thermal heads are respectively provided on both edges of a portion corresponding to each thermal head substrate on the supporting substrate having the same coefficient of thermal expansion as the thermal head substrate. Place a thickness gauge to make the height of the substrate uniform, place an adhesive on each part of this support substrate and place the corresponding thermal head substrate, and press a flat jig on the boundary between adjacent thermal head substrates. Then, the adhesive is cured to make the height of the surface of each thermal head substrate uniform.

In the thermal head and the method for manufacturing the same of the present invention, attention is paid to the fact that the thickness of the adhesive layer can be adjusted by applying a thickness gauge. By adjusting the layer thickness of the adhesive, the height of the surface of the thermal head substrate is adjusted. To prevent the print quality from deteriorating.

(E) Embodiment An embodiment of the present invention will be described below with reference to FIGS. 1 to 6.

Fig. 1 shows the state before placing the thickness gauges (thickness gauges) 3 _-1 , 3 _-1 , 3 _-2 , 3 _-2 made of stainless steel thin plate on the ceramic substrate (support substrate) 1. Shows. 2
_Reference numerals _-1 and _2-2 are thermal head substrates, each having a heating resistor 2 _a-1 2 _a-2 formed on a ceramic substrate. In the case of FIG. 1, the thickness t ₁ of the thermal head substrate 2 _-1 is larger than the thickness t ₂ of the thermal head 2 _-2 (t _1> t _2).

Regarding the thicknesses t _g1 and t _g2 of the thickness gauges 3 _-1 , 3 _-2 , the smaller one (t _{g1 in} this case) is the reference thickness of the adhesive, and t ₁ + t _g1 and t ₂ + t _g2 And are chosen to be equal. However, the thickness of the thickness gauge is, for example, 5 μm.
Since it is a step, it is difficult to completely equalize t ₁ + t _g1 and t ₂ + t _g2 , but it is sufficient here if the difference between the two is within a few μm.

If the portions to which the thermal head substrates 2 _-1 and 2 _-2 of the ceramic substrate 1 are fixed are 1 _-1 and 1 _-2 , respectively, these parts
Selected thickness gauges 3 _-1 , 3 _-2 are placed on the edges 1 _-1a , 1 _-2a of 1 _-1 , 1 _-2 , respectively.

FIG. 2 shows a state where the adhesive 4 is applied to the surface of the ceramic substrate 1. The adhesive 4, as the thermosetting resin of two-liquid mixing type is used, part 1 _-1, the thickness of 1 _-2 of
t _c1 and t _c2 are substantially equal to t _g1 and t _g2 , respectively (see FIGS. 3 (a) and 3 (b)). Thermal head substrates 2 _-1 , 2 _-2 are placed on the respective portions 1 _-1 , 1 _-2 of the ceramic substrate 1 to which the adhesive 4 is applied, and both edge portions 2 _b-1 , 2 thereof are placed.
_b-2 is supported by thickness gauges 3 _-1 , 3 _-2 , respectively. The means for adhering is not limited to the two-liquid mixed type adhesive, and the design can be changed as appropriate.

In this state, as shown in FIG. 4, heating is performed using jigs 6, 6, 8 and the like to cure the adhesive 4. The jigs 6 and 6 are
The thermal head substrates 2 _-1 , 2 _-2 are positioned in the longitudinal direction, and the screws 7, ..., 7 are screwed into a jig base (not shown), and the thermal head substrates 2 _-1 , 2 _-2 are aligned in the longitudinal direction. Position in the direction orthogonal to.

The jig 8 is a bridge-shaped member, and one end thereof is attached to the jig base with screws 8a, 8a. The other end of the jig 8 is pressed against the boundary portion A between the thermal head substrates 2 _-1 , 2 _-2 via the rubber material 8b of the cushion and the pressing member 8c. As the pressing member 8c, a member having a high degree of flatness such as a ceramic plate formed with glass glaze is used. The jig 8 is formed in a bridge shape so that the jig 8 does not come into contact with a driving IC (not shown) mounted on the thermal head substrates 2 _-1 , 2 _-2 .

The thermal head substrate 2 is pressed by the jig 8.
_-1, 2 _-2 center is deformed in, both the height h _1, h ₂ are aligned Fifth diagram (a) (b) refer to Fig. If the adhesive 4 is cured in this state, the deformed state of the thermal head substrates 2 _-1 , 2 _-2 is maintained, and the surfaces of the thermal head substrates 2 _-1 , 2 _-2 will be joined together evenly. .

Finally, the jigs 6 and 8 are removed from the ceramic substrate 1, and the heat sink 5 is attached to the bottom surface of the ceramic substrate 1 to complete the thermal head 10 (see FIG. 6).

In this thermal head 10, the thermal head substrate 2 _-1 , 2
_{Since the} thermal head substrates _2-1 and _{2-2 have} the same height at the boundary portion A of _-2 , the contact with the platen does not deteriorate and the print quality does not deteriorate. Further, since the ceramic substrate 1 and the thermal head substrates 2 _-1 and 2 _-2 are made of the same material, there is no risk of damage even if the thermal head substrates 2 _-1 and 2 _-2 are thermally expanded due to heat generation.

In addition, in the above-mentioned embodiment, the place where two thermal head substrates are joined is described, but it is also possible to join three or more thermal head substrates. Of course, even if three or more thermal head substrates are spliced together, there is no problem with respect to thermal expansion and print quality.

Further, the thickness gauge may be removed after the thermal head is completed, and the design can be changed appropriately.

(F) Effects of the Invention As described above, the thermal head of the first invention is provided with the adhesive layer whose thickness is adjusted by the thickness gauge on the supporting substrate having the same coefficient of thermal expansion as the thermal head substrate. A plurality of thermal head substrates are arranged side by side and attached, and the surface heights of the respective thermal head substrates are made uniform.

A method of manufacturing a thermal head according to a second aspect of the present invention comprises:
On both edges of the portion corresponding to each thermal head substrate, a thickness gauge that aligns the height of each thermal head substrate is placed, and an adhesive is provided on each portion of this support substrate to place the corresponding thermal head substrate. Then, a flat jig is pressed against the boundary between the adjacent thermal head substrates to cure the adhesive, and the height of the surface of each thermal head substrate is made uniform.

Therefore, there is no damage to the thermal head substrate due to thermal expansion, and deterioration of the printing quality due to variations in the thickness of the thermal head substrate is avoided, and a large thermal head in which a plurality of thermal head substrates, particularly three or more, are joined together is easy. Can be obtained.

[Brief description of drawings]

FIG. 1 is a perspective view illustrating a state in which a thickness gauge is mounted on a ceramic substrate in one embodiment of the present invention, and FIG. 2 is a perspective view illustrating a state in which an adhesive is applied to the ceramic substrate in the same embodiment. FIG. 3, FIG. 3 (a) and FIG. 3 (b) are respectively IIIa-IIIa line and IIIb-IIIb in FIG.
4 is a cross-sectional view taken along the line, FIG. 4 is a perspective view for explaining a state in which the ceramic substrate and the thermal head substrate are bonded using a jig in the same embodiment, and FIGS. 5 (a) and 5 (b) are 4 is a sectional view taken along line Va-Va and line Vb-Vb in FIG. 4, FIG. 6 is an external perspective view of the thermal head completed in the same embodiment, and FIG. 7 is a plan view of a conventional thermal head. FIG. 8 is a front view of the conventional thermal head. 1: Ceramic substrate, 2 _-1・ 2 _-2 : Thermal head substrate, 3
_-1 3 _-2: thickness gauge, 4: adhesives, 8: jig.

Claims (2)

[Claims] 1. A plurality of thermal head substrates are attached side by side on a supporting substrate having the same coefficient of thermal expansion as the thermal head substrate by means of an adhesive layer whose layer thickness is adjusted by a thickness gauge. A thermal head with the same height on the surface of the substrate. 2. A thickness gauge for aligning the height of each thermal head substrate is mounted on both edges of a portion corresponding to each thermal head substrate on a supporting substrate having the same coefficient of thermal expansion as the thermal head substrate. Then, an adhesive material is provided on each part of the support substrate and a corresponding thermal head substrate is placed thereon, and a flat jig is pressed against a boundary portion between adjacent thermal head substrates to cure the adhesive material. A method for manufacturing a thermal head in which the height of the substrate surface is made uniform.