JP2894932B2 - Structure of line type thermal print head - 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 line type thermal print head used for a facsimile or a printer.

[0002]

2. Description of the Related Art Conventionally, this type of line type thermal print head is described, for example, in Japanese Utility Model Laid-Open Publication No. 5-26394, and is constructed as shown in FIGS. That is, a linear heating resistor 3 ′ is formed on the upper surface of the heat radiating plate 1 ′ formed in a long shape by a metal plate such as aluminum.
And a head substrate 2 ′ provided with a driving IC 4 ′ for the heating resistor 3 ′ and the like, and the heating resistor 3 ′ and the driving A plurality of connection terminals 5 'for the IC 4' are collectively formed at a substantially central portion in the longitudinal direction of the head substrate 2 '.

On the other hand, on the upper surface of the heat sink 1 ', a reinforcing substrate 8' is attached to the lower surface of a flexible substrate 7 'formed to have a length L1' sufficiently shorter than the entire length of the head substrate 2 '. A connection circuit board 6 'is disposed such that its reinforcing board 8' is in close contact with the upper surface of the heat sink 1 '. A flexible board 7' in the connection circuit board 6 'is provided on the head board 2'. A plurality of connecting terminals 9 'are formed on the lower surface of the extending portion 7a' so as to contact each of the connecting terminals 5 'on the head substrate 2'. Further, a circuit pattern (not shown) for connecting each of the connection terminals 9 'and the socket 10' attached to the connection circuit board 6 'is formed on the connection circuit board 6'.

On the upper surface side of the connection circuit board 6 ', a long cover 11' for covering the driving IC 4 'of the head board 2' is provided.
The set screw 1 ′ is inserted from at least two screw holes 12 ′ at a substantially central portion in the longitudinal direction of the cover body 11 ′ into a female screw hole 13 ′ of the heat sink 1 ′. When fastening to the heat radiating plate 1 ', an elastic cord 18' made of rubber or the like is inserted into a groove 11a 'formed on the lower surface of the cover 11' so as to extend in the longitudinal direction. By pressing the extension 7a 'on the flexible board 7' of the connection circuit board 6 'at 18', each of the connection terminals 9 'on the lower surface of the extension 7a' is connected to the head board 2 '. It is configured to be connected to each connection terminal 5 '.

[0005] When a substantially central portion of the cover body 11 'is fastened by a pair of setscrews 14', the cover body 11 'is inserted into screw holes 15' formed at both longitudinal ends of the cover body 11 '. By screwing a set screw 17 ′ with a head into the female screw hole 16 ′ of the heat sink 1 ′, both ends of the cover body 11 ′ are prevented from floating.

By the way, in the above configuration, both ends of the cover body 11 'are connected to set screws 17' for the both ends.
The cover body 11 '.
Are fixed to the heat radiating plate 1 ', so that the thermal expansion between the cover 11', the heat radiating plate 1 'and the head substrate 2' when the heat generating resistor 3 'generates heat. Due to the bimetal effect caused by the difference between the rates, the entire thermal print head is deformed in a bow shape, resulting in uneven printing.

Therefore, conventionally, setscrews 17 'for both ends of the cover body 11' are attached to the head 17 '.
a ′ and the diameter d of the threaded portion 17b ′ between the threaded portion 17b ′
Screwless shaft 17 having a diameter d2 'larger than 1'
By forming the stepped screw provided with c 'and by defining the screw-in dimension of the screw 17', it is configured to prevent excessive tightening of both ends of the cover body 11 '. I have.

[0008]

However, the cover 1
In the case where the set screws 17 'for both ends in 1' are configured as stepped screws as described above, the length under the neck of the set screw 17 'in the screwless shaft portion 17c' is shown in FIG. , The heat sink 1
The height H 'from the upper surface of the set screw 17' to the top surface of the head 17a 'of the set screw 17' is reduced, so that the head 17a 'of the set screw 17' is connected to the head substrate 2 'and the platen roller 19'. Printing paper 20 'sent between
On the other hand, the pressing force of the setscrew 17 'on both ends of the cover body 11' is increased, so that the warp deformation of the thermal print head due to the bimetal effect is increased. Will be.

When the length under the neck of the screw-free shaft portion 17c 'of the set screw 17' is increased to S "as shown in FIG. 13, the set screw 17 'for both ends of the cover body 11' is formed. Of the thermal print head, the warp deformation due to the bimetal effect can be reduced, but the height H from the upper surface of the heat sink 1 to the top surface of the head 17a 'in the set screw 17' is reduced. Is higher, the head 17a 'of the set screw 17' is connected to the head substrate 2 'and the platen roller 19'.
Contact (contact) with the printing paper 20 ′ sent between them.

That is, if the set screws 17 'for both ends of the cover body 11' are formed as stepped screws as in the prior art, the warpage of the thermal print head can be reduced, and the paper contact of the set screw 17 'can be reduced. There is a problem that prevention cannot be achieved at the same time. Moreover, in the prior art, the screw holes 15 'for the set screws 17' at both ends of the cover body 11 'are formed as complete circular holes, so that the cover body 11' is separated from the axis of the set screw 17 '. ′ Must be increased to one longitudinal side 11b ′, and the overall width dimension W ′ of the thermal printhead increases, so that the size and weight of the thermal printhead can be reduced. However, there was also a problem that it could not be achieved sufficiently.

It is a technical object of the present invention to provide a structure capable of solving the above-mentioned problems in a line type thermal print head as described above.

[0012]

In order to achieve this technical object, the present invention provides a method of manufacturing a semiconductor device comprising the steps of providing a linear heating resistor and a driving IC on an upper surface of a head substrate provided with a heat sink on a back surface; A plurality of connection terminals for the heating resistor and the driving IC are collectively formed at a substantially central portion in the longitudinal direction of the head substrate, while a connection circuit board having a length shorter than the entire length of the head substrate is formed. On the head substrate, each connection terminal on the lower surface of the connection circuit board is disposed so as to overlap with each connection terminal on the head substrate, and on the upper surface side, the length is substantially the same as that of the head substrate. The cover body thus formed is disposed, and the cover body is fitted with an elastic cord body such as rubber in a groove provided on the lower surface thereof so as to extend along the longitudinal direction. And screw it to the heat sink Signed at arranged the set screw in,
Further, a head set screw is inserted into a screw hole drilled at both ends of the cover so that the set screw is screwed to the heat sink, and each head set screw is inserted into the head. In a line-type thermal print head configured as a stepped screw provided with a screwless shaft portion between the screw portion and a screw portion, the head of the set screw with respect to both ends of the cover body on the upper surface of the cover body. A counterbore surface is formed in the contacting portion. ".

[0013]

In this manner, the counterbore face is formed in the upper surface of the cover body at the portion where the heads of the set screws contact the opposite ends of the cover body, so that the screw of the set screw can be removed. Without increasing the length under the neck in the shaft portion, in other words, without increasing the height from the upper surface of the heat sink to the top surface of the head of the set screw, the stop for the both ends of the cover body is not required. The pressing force by the screw can be reduced by the depth dimension of the counterbore surface.

[0014]

Therefore, according to the present invention, in a line type thermal print head, a paper hit occurs on a set screw having a head with respect to both ends of a cover body,
This has the effect of significantly reducing warpage of the thermal print head.

[0015] Further, according to the present invention, the dimension from the axis of the set screw to both ends of the cover body to one longitudinal side surface of the cover body can be changed to a completely circular screw hole as in the prior art. Since the size can be reduced as compared with the case where the holes are formed, the width of the thermal print head can be reduced, and the size and weight of the thermal print head can be reduced.

[0016]

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 1 denotes a heat radiating plate formed in a long shape from a metal plate of aluminum or the like. On the upper surface of the heat radiating plate 1, a line-shaped heating resistor 3 Substrate 2 provided with a plurality of driving ICs 4 for
A plurality of connection terminals 5 for the heating resistor 3 and the respective driving ICs are formed on one side edge of the head substrate 2 in the longitudinal direction at a substantially central portion in the longitudinal direction. I have.

Reference numeral 6 denotes a connection circuit board formed by attaching a reinforcing substrate 8 to the lower surface of a flexible circuit board 7, and the length L 1 of the connection circuit board 6 is different from that of each connection board in the head substrate 2. The terminal 5 is formed substantially shorter than the entire length of the head substrate 2 in association with the formation of the terminal 5 substantially in the center, and the flexible substrate 7 of the connection circuit substrate 6 is formed.
Is provided on one side edge in the longitudinal direction of the head substrate 2 with an extension 7a overlapping with the head substrate 2, and a lower surface of the extension 7a is in contact with each of the connection terminals 5 on the head substrate 2. A plurality of connection terminals 9 are formed,
The connection circuit board 6 includes the connection terminals 9.
And a circuit pattern (not shown) for electrically connecting the socket 10 attached to the other side edge of the connection circuit board 6.

Reference numeral 11 denotes a cover formed in a long shape so as to cover each of the driving ICs 4 in the head substrate 2. The cover 11 is made of metal such as aluminum. The cover body 11 is fastened to the heat sink 1 by a set screw 14 inserted from at least two screw holes 12 at a substantially central portion in the longitudinal direction into a female screw hole 13 of the heat sink 1. At this time, an elastic cord 18 made of rubber or the like is inserted into a groove 11a formed in the lower surface of the cover 11 so as to extend in the longitudinal direction, and the flexible cord 18 of the connection circuit board 6 is inserted by the elastic cord 18. 7, each of the connection terminals 9 on the lower surface of the extension 7a is connected to each of the connection terminals 5 on the head substrate 2. It is configured so as.

When a substantially central portion of the cover body 11 is fastened by a pair of set screws 14,
The set screws 17 with heads inserted into the screw holes 15 formed at both ends in the longitudinal direction of the cover body 11
By screwing into the female screw hole 16 in the above, both ends of the cover body 11 are prevented from being lifted up. In this case, the head stopper for the both ends of the cover body 11 is used. The screw 17 is configured as a stepped screw having a screwless shaft portion 17c having a diameter d2 larger than the diameter d1 of the screw portion 17b between the head portion 17a and the screw portion 17b.

The screw holes 15 formed at both ends of the cover body 11 are inserted into the cover body 1.
1 is formed in a slot opening on one longitudinal side surface 11b, while the screw hole 15 is an opening on the upper surface of the cover body 11, that is, the set screw on the upper surface of the cover body 11 on both ends of the cover body 11. A counterbore surface 21 having a depth dimension D is appropriately formed in a portion where the head 17a of the base 17 contacts.

As described above, on the upper surface of the cover 11, the set screws 17 for both ends of the cover 11 are provided.
By forming a counterbore surface 21 in a portion where the head 17a of the set screw abuts, the screwless shaft portion 1 of the set screw 17 is formed.
7c without increasing the length S under the neck, in other words, without increasing the height H from the upper surface of the heat sink 1 to the top surface of the head 17a of the set screw 17 in the cover body 11. The pressing force of the set screw 17 on both ends can be reduced by the depth dimension D of the counterbore surface 21.

As a result, the head 17a of the setscrew 17 at both ends of the cover 11 greatly contacts (contacts) the printing paper 20 fed between the head substrate 2 and the platen roller 19. And
It is possible to significantly reduce the occurrence of warpage deformation due to the bimetal effect in the thermal print head. Further, as described above, the screw holes 15 for the setscrews 17 at both ends of the cover body 11 are formed in the groove holes that open in the one longitudinal side surface 11b of the cover body 11 as described above. Since the dimension T from the axis of the setscrew 17 to both ends of the cover 11 and the one longitudinal side surface 11b of the cover body 11 can be reduced as compared with the conventional case where the screw hole is a perfect circular hole, thermal printing is possible. The width dimension W of the head can be reduced.

The set screws 17 with heads at both ends of the cover body 11 are, as shown in FIG.
It is needless to say that the number is not limited to one for one end and may be plural for one end.

[Brief description of the drawings]

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

FIG. 2 is a side view taken along the line II-II of FIG.

FIG. 3 is an enlarged sectional view taken along line III-III of FIG. 1;

FIG. 4 is an enlarged sectional view taken along line IV-IV of FIG. 1;

FIG. 5 is a perspective view of the thermal print head shown in FIG. 1 when disassembled.

FIG. 6 is an enlarged sectional view taken along line VI-VI of FIG. 5;

FIG. 7 is an enlarged perspective view of a cover body according to the present invention.

FIG. 8 is a plan view showing a conventional thermal print head.

9 is a IX-IX side view of FIG.

FIG. 10 is an enlarged sectional view taken along line XX of FIG. 8;

FIG. 11 is an enlarged sectional view taken along line XI-XI of FIG. 8;

FIG. 12 is a perspective view when the thermal print head shown in FIG. 8 is disassembled.

FIG. 13 is a cross-sectional view showing a modification of the related art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heat sink 2 Head board 3 Heating resistor 4 Driving IC 5 Connection terminal 6 Connection circuit board 7 Flexible board 8 Reinforcement board 9 Connection terminal 11 Cover body 12,15 Screw hole 13,16 Female screw hole 14,17 Stop Screw 18 Elastic cord 21 Counterbore surface

Claims (2)

(57) [Claims] 1. A linear heating resistor and a driving IC are provided on an upper surface of a head substrate having a heat radiating plate on a back surface, and a plurality of connection terminals for the heating resistor and the driving IC are provided. On the head substrate, a connection circuit board having a length shorter than the entire length of the head substrate is formed on a substantially central portion in the longitudinal direction, and the connection terminals on the lower surface of the connection circuit board are formed on the head substrate. The head substrate is disposed so as to be in contact with each connection terminal, and a cover body formed to have substantially the same length as the head substrate is disposed on the upper surface side, and the cover body is disposed on the lower surface thereof. A set screw arranged to fit an elastic cord body such as rubber into a groove provided to extend along the longitudinal direction and to be screwed to the heat sink at a substantially central portion of the head substrate in the longitudinal direction. , And furthermore,
Insert a set screw with a head into a screw hole drilled at both ends of the cover body so that the set screw is screwed to the heat sink. And a stepped screw having a screwless shaft portion between the head and the head of the set screw with respect to both ends of the cover body on the upper surface of the cover body. The structure of the line type thermal print head, characterized in that the counterbore surface is formed in a recessed portion. 2. Screw holes at both ends of the cover body,
2. The structure of the line type thermal print head according to claim 1, wherein said screw hole is formed in a groove opening on one longitudinal side surface of the cover body.