JP2859804B2 - Thermal printhead structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a thermal print head used for a printing device such as a facsimile.

[0002]

2. Description of the Related Art Generally, as shown in FIGS. 6 to 8, this type of thermal print head has a head substrate 2 on which a heating resistor 3 for printing is formed on an upper surface, and a thermal radiation plate 1 made of metal. The heat sink 1 is fixed by an adhesive or the like.
A female screw which is placed on the upper surface of the frame member 4 of the printing apparatus and the tip of a mounting screw 6 inserted into a screw hole 5 formed in the lower surface of the frame member 4 and inserted into the screw hole 5 is formed in the heat sink 1. After being screwed into the hole 7, each of the mounting screws 6
Is screwed into the heat sink 1 with the head substrate 2.
Is attached to the frame member 4.

[0003]

However, in this structure, when the mounting screw 6 is fully screwed in, the tip of the mounting screw 6 does not protrude from the upper surface of the heat sink 1. In this case, when the thickness T of the heat sink 1 is reduced, the number of screw threads that can be screwed into the female screw holes 7 of the heat sink 1 is reduced, and the mounting strength is reduced. Not only is it low, but there is a problem that the thread is frequently crushed when screwed.

For this reason, conventionally, the thickness T of the heat radiating plate 1 is considerably increased over the whole, and the heat radiating plate 1 is made of aluminum or aluminum alloy. However, this greatly increases the material cost. As a result, the price rises significantly. On the other hand, when the heat sink is made of a thin carbon steel plate in order to reduce the price, as shown in FIG.
The heat radiating plate 1a is integrally provided with a protruding portion 1a 'on the upper surface thereof outside the head substrate 2a, and a mounting screw 6a is screwed into a female screw hole 7a formed in the protruding portion 1a'. In this configuration, the heat sink 1a is provided with the protrusion 1
Since a 'must be increased by the amount provided integrally, the size of the heat radiating plate 1a is increased.

An object of the present invention is to provide a structure capable of solving these problems.

[0006]

In order to achieve this technical object, the present invention provides a method of fixing a head substrate provided with a heating resistor on the upper surface of a metal radiator plate, In a thermal print head formed with a female screw hole for a mounting screw, a part of a peripheral edge of the heat sink is integrally provided with a mounting piece bent so as to be in close contact with the back side of the heat sink. The female screw hole is formed in the mounting piece, and a relief hole for the tip of the mounting screw is formed in a portion of the heat sink corresponding to the female screw hole in the mounting piece. " .

[0007]

In this configuration, a heat radiating plate provided with a head substrate on an upper surface is mounted on a frame member of a printing apparatus, and is then inserted from a lower surface side of the frame member into a screw hole formed in the frame member. The tip of the screw is screwed into the female screw hole of the mounting piece provided in a part of the heat sink, and screwed in, so that the tip of this mounting screw looks into the relief hole drilled in the heat sink. Therefore, the tip of the mounting screw protrudes from the upper surface of the heat sink under a state where the number of screw threads to be screwed into the female screw holes of the mounting piece of the mounting screw is sufficiently secured. This can be avoided, and the thickness of the heat sink can be prevented from being increased throughout.

[0008]

Therefore, according to the present invention, the thickness of the radiator plate can be reduced under the condition that a reliable mounting strength can be obtained and damage to the screw thread at the time of mounting and removing can be reduced. This has the effect that the thickness can be reduced over the entirety and the heat sink can be reliably prevented from increasing in size.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In this figure, reference numeral 11 denotes a radiator plate formed in a strip shape on a thin carbon steel plate.
A head substrate 12 provided with a heating resistor 13 for printing on the upper surface is fixed to the upper surface with an adhesive or the like.

At the left and right ends of the heat radiating plate 11, mounting pieces 11a which are bent so as to be in close contact with the back side of the heat radiating plate 11 are integrally provided, and female screw holes 17 are formed in both the mounting pieces 11a. An escape hole 18 having a diameter larger than that of the female screw hole 17 is formed at a position corresponding to the female screw hole 17 of the both mounting pieces 11a of the heat sink 11.

In this configuration, the head substrate 12 is provided on the upper surface.
After mounting the heat radiating plate 11 provided on the frame member 14 of the printing apparatus, the mounting screw 1 inserted into the screw hole 15 formed in the lower side of the frame member 14 is provided.
6 is screwed into female screw holes 17 of both mounting pieces 11a provided at both ends of the heat radiating plate 11 and screwed into the hole. 18 will be looked into.

Therefore, the tip of the mounting screw 16 is
In a state where the number of screw threads to be screwed into the female screw holes 17 of both mounting pieces 11a of the mounting screw 16 is sufficiently ensured, it is possible to prevent the mounting screw 16 from protruding from the upper surface of the heat radiating plate 11, and It is possible to avoid increasing the thickness of the plate 11 throughout. In the embodiment, the heat radiating plate 11 is provided at both ends of the heat radiating plate 11.
Mounting piece 11a bent so as to be in close contact with the back side of
5 is provided integrally, but in another embodiment, as shown in FIG. 5, a part of the longitudinal side edge of the heat radiating plate 11 ′ is in close contact with the back side of the heat radiating plate 11 ′. The bent attachment piece 11a 'may be provided integrally, and a female screw hole 17' may be formed in the attachment piece 11a '.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a thermal printhead according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view taken along line II-II of FIG.

FIG. 3 is a perspective view showing a back surface of the heat sink according to the embodiment of the present invention.

FIG. 4 is a sectional view showing a mounting state of the thermal print head according to the embodiment of the present invention.

FIG. 5 is a perspective view showing a back surface of a heat sink according to another embodiment of the present invention.

FIG. 6 is an exploded perspective view of a conventional thermal print head.

FIG. 7 is an enlarged sectional view taken along line VII-VII of FIG. 6;

FIG. 8 is a cross-sectional view showing a mounting state of a conventional thermal print head.

FIG. 9 is a cross-sectional view showing another example in the related art.

[Explanation of symbols]

 11, 11 'Heatsink 11a, 11a' Mounting piece 12 Head substrate 13 Heating resistor 14 Frame member 15 Screw hole 16 Mounting screw 17 Female screw hole 18 Escape hole

Claims (1)

(57) [Claims] 1. A thermal print head comprising: a head substrate having a heating resistor provided on an upper surface thereof fixed to an upper surface of a metal radiator plate; and a female screw hole for a mounting screw formed in the radiator plate. A part of the peripheral edge of the heat sink is provided integrally with a mounting piece bent so as to be in close contact with the back side of the heat sink, and the female screw hole is formed in the mounting piece while A thermal printhead structure, wherein a relief hole for the tip of the mounting screw is formed at a position corresponding to a female screw hole in the mounting piece.