JPH11138879A - Substrate for thermal head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To relax deformation and stress at the heating element part and the IC mounting part by making thick the part to be protected against bending strain in a sublimation or TA color printer and making thin the part where bending strain substantially causes no problem. SOLUTION: A substrate for thermal head comprises a heating element part 10a, a wiring part 10b, and an IC mounting part 10c and a general method of rolling, cutting, grinding or etching is applied for making thin the wiring part 10b on a metal plate of stainless steel, or the like, sandwiched by glaze glass layers 2, 3. The metallic substrate at the heating element part 10a and the IC mounting part 10c is made thicker than other parts in order to enhance bending rigidity. Consequently, the heating element part 10a and the IC mounting part 10c are not deformed but only the individual electrode wiring part 10b is deformed upon bending. According to the structure, quality of the heating element can be enhanced and bonding of a control IC can be stabilized easily.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal head used in a thermal recording apparatus or a thermal transfer recording apparatus, and more particularly, to a thermal head substrate.

[0002]

2. Description of the Related Art The following publications are disclosed with respect to conventional thermal head substrates. As shown in FIG.
FIG. 3A is a perspective view, and FIG. 3B is a cross-sectional side view taken along line BB of FIG. In these figures, there is a glaze glass layer 2 on the upper surface of a metal substrate 1 ′ and a partial glaze glass layer 2 ″ on the lower surface. The partial glaze glass layer 2 ″ is divided by a notch 12, and corresponds to the notch 12. The glaze glass layer 2 is disposed on the upper surface of the metal substrate 1 ', and a heating resistor (not shown) is disposed thereon. As shown in FIG. 4, the notch 12 is filled with a thermally conductive putty 15 and heat is radiated from the putty 15 through a heat sink 16, so that "undulation" and "warpage" of the substrate 1 'due to heat are improved. You. FIG.
70 is a front view of a metal substrate thermal head of No.
A is curved, and the control IC 28
3 and ink 24 and paper 2
6A so as not to hinder the straight traveling of the vehicle, 21A is a radiation fin, and 27 is a platen roller. FIG. 5B shows an example in which the substrate 20A is bent. FIG. 6 shows an assembly of a thermal head including a curved substrate 20A, 21 is a radiation fin, 20A is a thermal head, and 2A is a thermal head.
8 is a control IC, and 29 is a mounting screw.

FIGS. 7 and 8 show one end 31b of a metal substrate 31 in a front view and a top view, respectively, of a thermal head filed by the present applicant as Japanese Patent Application No. 8-35312. Glazed layers 32a and 32b of glass or the like are attached to the upper and lower surfaces of the bent portion 34 and the flat portion that is not bent, and the flat portion 31b ahead of the bent portion 36 is attached. The flat portion 31a, which is not bent, is attached to the heat sink 33 with an adhesive or a mounting screw to form a structure having spring properties, thereby improving the uniformity of contact with the ink ribbon and eliminating print density unevenness. Things. FIG. 9 is a perspective view of a thermal head insulating metal substrate 50 filed by the applicant of the present invention as Japanese Patent Application No. 9-186021, which shows a chrome 1
A protrusion 52 serving as a common electrode formed on the surface of a metal substrate 51 made of an iron alloy containing 0 to 30% by weight and 0.1 to 6% by weight of aluminum, and an aluminum oxide formed on the surface of the metal substrate. a rich oxide film, crystalline glass paste 54a formed on the oxide film, 54b (FIG. 10, 54b _1, 54b ₂₎ and, glaze glass paste 54c ₁ formed on the crystalline glass paste, 54c ₂
(See FIG. 10), the substrate 51 made of an iron alloy having a thermal expansion coefficient of the crystalline glass and the glaze glass
Since the coefficient of thermal expansion is smaller than 1, it is possible to eliminate surface defects such as "warpage" and foaming generated during melting.

[0004]

In consideration of the bending process, which is a feature of the metal substrate, it is desirable that the heating resistor portion and the IC mounting portion have a structure in which bending stress is not applied as much as possible. This is because there is a possibility that the resistance value of the heating element fluctuates due to bending strain caused by pulling or compression, the pulse life can be shortened, the bonded IC is peeled off, or a malfunction occurs. In the structure of FIG. 3 described above, the thickness of the metal plate is uniform, but there is a notch 12 in the glaze glass layer, and such a notch has low rigidity and is concentrated on bending. It is deformed, and its position is directly below the heating resistor, which is not suitable for bending. 5 and 6, the bending deformation is uniform, but the deformation also occurs uniformly in the heating resistor portion and the IC mounting portion, which is not preferable.
Although the structures shown in FIGS. 7 and 8 and FIGS. 9 and 10 have been improved, similar disadvantages remain when bending is performed. Therefore, it is an object of the present invention to provide a thermal head structure that reduces deformation and stress applied to the heat generating resistor portion and the IC mounting portion.

[0005]

SUMMARY OF THE INVENTION A substrate for a thermal head according to the present invention is used for a sublimation or a TA color printer in which bending distortion is not required, for example, a thickness of a heating resistor portion, an IC mounting portion, and the like. The above problem has been solved by a structure in which the thickness is increased and the thickness of the portion where bending distortion is unlikely to be a problem is reduced.

[0006]

FIG. 1 shows a first embodiment of a substrate for a thermal head according to the present invention. FIG. 1 (A) is a front view before bending, and FIG. 1 (B) is after bending. In the front view, 10a, 10b, and 10c denote a heating resistor unit, a wiring unit, and an IC mounting unit, respectively. The process of thinning the wiring portion 10b of the metal plate 1 such as stainless steel is performed by rolling, cutting,
General methods such as polishing and etching are applied. Reference numerals 2 and 3 denote a glaze glass layer, 4 denotes a partial glaze glass, and 5 denotes a control IC.

Next, second to eighth embodiments shown in FIGS. 2A to 2G will be described. FIG. 2A showing the second embodiment is a diagram showing a third embodiment in which a lower surface of a metal substrate 1a and a lower glaze glass layer 3 are deformed in the drawing of the metal substrate 1a. In (B) of FIG. 2, on the contrary, the upper glaze glass layer 2b in the figure and the metal substrate 1b under the glaze glass layer 2b are deformed to form the wiring portion 10b. Fourth,
In FIG. 2 (C) showing the fifth and sixth embodiments, the intermediate metal substrate 1c is not deformed, and
2 (E), the metal substrate 1c is not deformed as in FIG. 2 (C), and only the wiring portion 10b of the lower glaze glass layer 3c of the wiring portion 10b is deformed. In FIG. The glaze glass layer 3 and the metal substrate 1c are not deformed,
Only the wiring portion 10b of the upper metal substrate 2c in the figure was deformed. In FIG. 2F showing the seventh embodiment, the wiring portion 10b of the glaze glass layer 3 on the lower surface in the view of the wiring portion 10b of FIG. And In FIG. 2G showing the eighth embodiment, a common electrode projection 52g and a crystalline glass paste 54 are provided at the center.
g ₁ , 54g ₂ , control IC 5a at both left and right ends
In the figure, 1 g is a metal substrate, and 2 g and 3 g are glaze glass layers.

[0008]

According to the thermal head substrate of the present invention, the bending rigidity is increased by making the thickness of the metal substrate of the heating resistor portion and the IC mounting portion larger than the other portions as described above.
Therefore, when FIG. 1A is bent, the shape deformation shown in FIG. 1B is obtained. That is, the heating resistor portion 10a and the IC mounting portion 10c are not deformed, and only the individual electrode wiring portion 10b is deformed, so that the quality of the resistor can be made highly reliable and the control IC bonding can be relatively easily and inexpensively obtained. Can be

[Brief description of the drawings]

FIG. 1A is a front view of a thermal head substrate according to a first embodiment of the present invention before bending, and FIG. 1B is a front view after bending.

FIGS. 2A to 2G are front views showing second to eighth embodiments of the thermal head substrate of the present invention, respectively.

FIG. 3A is a perspective view of a metal substrate for a thermal head disclosed in Japanese Patent Application Laid-Open No. 2-200552, and FIG. 3B is a cross-sectional side view taken along the line BB of FIG. is there.

FIG. 4 is a front view of an assembly in which a cutout portion of the substrate of FIG. 3 is filled with a heat conductive putty and combined with a heat sink.

FIG. 5 is a front view of a metal substrate for a thermal head disclosed in Japanese Patent Application Laid-Open No. 2-258270, wherein FIG. 5 (A) is a curved one and FIG. 5 (B) is a bent one.

FIG. 6 is a perspective view of the thermal head shown in FIG.

FIG. 7 is a front view of a thermal head filed by the present applicant.

FIG. 8 is a top view of the thermal head of FIG. 7;

FIG. 9 is a perspective view of a thermal head insulating metal substrate filed by the present applicant.

FIG. 10 is a partially modified view of the thermal head insulating metal substrate shown in FIG. 9;

[Explanation of symbols]

1, 1a, 1b, 1c, 1g: Metal substrate 2, 2a, 2b, 2c, 2g, 3, 3c, 3f, 3g:
Glaze glass layer 4: the partial glaze glass layer 5: Control IC 10a: heating resistor portion 10b: wiring portion 10c: IC mounting portion 52 g: common electrode projections 54g _1, 54g _2: crystalline glass paste

Claims (4)

[Claims] 1. A metal plate which is used as a thermal head in a curved or bent form as a substrate for a thermal head made of a metal body such as an iron alloy containing Cr and Al or stainless steel. Thermal head substrate. 2. A thermal head substrate made of a metal body such as an iron alloy containing Cr and Al or stainless steel, wherein a thickness of a portion where bending distortion is not required such as a heating resistor portion and an IC mounting portion is set. A thermal head substrate that has been processed by adjusting its thickness so that the thickness of the part that is large and where bending distortion is not a problem is reduced. 3. The thermal head substrate according to claim 2, wherein the thickness adjustment is performed with a metal plate thickness, a glaze glass layer thickness, or both. 4. The width of the curved portion for adjusting the thickness of the sheet according to claim 2 can be bent as long as it is not less than the thickness of the sheet. A substrate for a thermal head, wherein the substrate is not required.