JP2539169Y2 - Thermal head unit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention relates to a thermal head unit having a thermal head for forming an image on a recording paper by heating a thermosensitive recording paper, a heat-fusible carbon film or the like. Things.

(Prior Art) FIG. 4 is an exploded perspective view of a conventional thermal head unit, and FIG. 5 is an assembled perspective view of the thermal head unit shown in FIG. 4, wherein 1 is about 5 to 8 mm thick. A radiator plate made of a plate material such as aluminum, steel, stainless steel, or the like. Four screw holes 2 are provided in the longitudinal direction in the middle of the radiator plate 1, and a notch 1a for housing a connector is provided at a rear end. Have been. Reference numeral 3 denotes a ceramic substrate 3a having a thickness of 1.2 mm or more, in which a number of minute heating elements 3b are arranged in a predetermined pattern in the longitudinal direction at the front end of the surface of the substrate 3a, The thermal head 4 has a plurality of contacts 4a arranged in the longitudinal direction at the rear end in the drawing, and a lead wire pattern connected to the contacts 4a is appropriately arranged. A printed wiring board (hereinafter referred to as a “wiring board”) has four screw insertion holes 5
Are arranged in the longitudinal direction, and a connector (not shown) connected to the lead wire pattern is attached to the rear end of the rear surface in the figure. Reference numeral 6 denotes a flexible printed wiring board retainer (hereinafter referred to as “wiring board retainer”) interposed between the wiring board 4 and the heat sink 1.
), Four screw insertion holes 7 are provided in the middle of the wiring board retainer 6 in the longitudinal direction. Reference numeral 8 denotes a front pressing rubber 9 at the rear front end in the figure, and a rear pressing rubber 9 at the rear end in the drawing.
Each of the protective covers 10 is attached in the longitudinal direction, and four screw insertion holes 11 are provided in the middle of the protective cover 8 in the longitudinal direction. Reference numeral 12 denotes a harness having one end connected to a thermal head control means (not shown), and the other end connected to a connector 13 for connecting the other end to a connector on the wiring board 4. Fourteen screws 14 are respectively screwed into the four screw holes 2. Reference numeral 15 denotes a fixture for attaching the assembled thermal head unit to a predetermined position of a frame (not shown) of a recording apparatus or the like. The fixture 15 is screwed to the back of the heat sink 1 in the figure.

In order to assemble the thermal head unit in the conventional example configured as described above, first, the thermal head 3 is placed at a predetermined position in front of the radiator plate 1 and the screw insertion hole 7 is inserted into the radiator plate 1. The wiring board retainer 6 is placed on the rear part of the heat sink 1 so as to fit the screw hole 2.

Next, the wiring board 4 was placed on the thermal head 3 and the wiring board holder 6 such that the contact 4a was in contact with the contact 3c of the thermal head 3 and the screw insertion hole 5 was aligned with the screw insertion hole 7 of the wiring board holder 6. (See FIG. 5.) The protective cover 8 is placed on the wiring board 4 so that the screw insertion holes 11 match the screw insertion holes 5 of the wiring board 4.

Finally, when the screws 14 inserted in the screw insertion holes 11, 7 and 5 are screwed into the screw holes 2, the front end and the rear end of the wiring board 4 become the front pressing rubber 9 and the rear pressing rubber 9 of the protective cover 8. The contact 4a of the wiring board 4 is pressed by the heat sink 1
Is pressed into contact with the contact 3c of the thermal head 3, and at the same time, the thermal head 3, the wiring board presser 6, and the wiring board 4 are attached to the heat sink 1.

And the thermal head / assembly thus assembled
The unit is attached to a predetermined position of a frame of a recording device or the like via the attachment 15, and in this state, the thermal head unit is moved by spring means (not shown) interposed between the attachment 15 and the frame. It is pressed against a platen (not shown) at a pressure of 4 to 5 kg / cm ² ,
Variation in flatness with a is absorbed.

(Problems to be solved by the invention) In the above-described conventional thermal head unit, the independent heat sink 1, thermal head 3, wiring board 4,
After assembling the wiring board retainer 6, the protective cover 8, and the like, the assembly was attached to a predetermined frame (equipment main body) of a recording device or the like by an attachment 15 which is also an independent member. The thermal head unit is pressed against the platen by using an independent spring means.

Thus, in the conventional thermal head unit,
The number of components that make up the thermal head unit and the number of components for installing the thermal head unit on the equipment body are large, making assembly and installation difficult, making it difficult to achieve positional accuracy, and making maintenance complicated. This has increased the manufacturing cost of the thermal head unit.

SUMMARY OF THE INVENTION An object of the present invention is to provide a thermal head unit which can easily achieve high positional accuracy, can reduce the number of parts, can be easily assembled and maintained, and can reduce manufacturing costs.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a thermal head for forming an image on recording paper by generating heat from a large number of minute heating elements arranged in a predetermined pattern. In a thermal head unit attached to a heat radiating member, a pair of opposed positioning portions for positioning the heating element, and a pair of opposed attaching portions for attaching the thermal head unit to a device body. The heat radiating member is formed integrally with both ends in the longitudinal direction, and a pressure contact portion for pressing the thermal head unit in the platen direction is formed integrally with the heat radiating member.

(Operation) Since the above means is adopted, the heating element is positioned by the positioning portions formed integrally at both ends in the longitudinal direction of the heat dissipating member, and the press contact portion also formed integrally with the heat dissipating member makes the platen direction. In addition, the thermal head unit can generate a pressure contact force to the thermal head unit.Furthermore, the thermal head unit can be installed on the main body of the equipment by the mounting parts formed integrally at both ends in the longitudinal direction of the heat radiating member. The thermal head unit is assembled and installed on the basis of the heat dissipating member, the number of components is reduced, the assembly and maintenance are easy, and the manufacturing cost can be reduced. . Further, even if thermal expansion occurs in the heat radiating member, the positioning portion and the mounting portion are integrally formed on the heat radiating member, so that the displacement and rattling between the positioning portion and the mounting portion are minimized, and the printing quality is reduced. The drop can be prevented.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is an exploded perspective view of a thermal head unit according to an embodiment of the present invention, and FIG. 2 is an assembled perspective view of the thermal head unit shown in FIG. In the support plate, positioning pins 17 serving as positioning portions protrude from a front portion and a middle portion of the support plate 16, and four screw holes 18 are provided in a rear portion in a longitudinal direction. Reference numeral 19 denotes a positioning foot projecting from the front side of the support plate 16 on both sides, and reference numeral 20 denotes a support plate.
16 are mounting feet which are mounting portions protruding from the surface side of both rear end portions. The positioning pin 17, screw hole 18, positioning foot 1
9, The mounting feet 20 are formed integrally with the support plate 16. Reference numeral 21 denotes a ceramic substrate 21a in which a large number of minute heating elements 21b are arranged in a predetermined pattern in the longitudinal direction at the front end of the surface of the substrate 21a, and the substrate 21a
The thermal head 22 has a large number of contacts 21c arranged in the longitudinal direction at the rear end of the surface in FIG.
a is a flexible printed wiring board (hereinafter referred to as a “wiring board”) in which a lead wire pattern connected to the contact point 22a is appropriately disposed, and four screws are provided at the rear of the wiring board 22. An insertion hole 23 is provided in the longitudinal direction, and a connector for connecting to a lead wire pattern is provided at the rear end of the surface in the drawing.
24 are installed. 25 is made of a material having good heat conductivity as described later, and is provided on the support plate 16 to support the support plate.
A heat radiation sheet 16 constitutes a heat radiation member. Reference numeral 26 denotes a protective cover in which a pressing rubber 27 is attached to the front end of the rear surface in the figure in the longitudinal direction. Four screw insertion holes 28 are provided in the middle of the protective cover 26 in the longitudinal direction. It is arranged in. Reference numeral 29 denotes four screws respectively screwed into the four screw holes 18, and reference numeral 30 denotes a pressure contact portion provided integrally with the support plate 16 so as to protrude rearward.

As shown in the perspective view of the back surface of the support plate in FIG. 3, the support plate 16 has a flexible structure in which the back surface is lightened in a lattice shape, and is provided so that the pair of press-contact portions 30 have elasticity. The central part is slightly (several tens μ) convex. Further, the heat dissipation sheet 25 is attached to the support plate 16 by being joined to the upper portion. If the support plate 16 is formed by resin molding, the heat dissipation sheet 25 is integrally attached by insert molding.

The heat radiating sheet 25 is made of a material having good heat conductivity such as aluminum while the support plate 16 is a heat insulator (resin molded product, metal product having poor heat conductivity). It is preferable to use a thin sheet to make

To assemble the thermal head unit in the present embodiment configured as described above, first, the thermal head 21 is moved to a predetermined position on the front portion of the support plate 16 while the front end and both side ends of the thermal head 21 abut against the positioning pins 17. Place in position.

Next, the wiring board 22 is placed on the thermal head 21 and the support plate 16 so that the contact 22a contacts the contact 21c of the thermal head 21 and the screw insertion hole 23 matches the screw hole 18 of the support plate 16,
The protective cover 26 is placed on the wiring board 22 so that the screw insertion holes 28 match the screw insertion holes 23 of the wiring board 22.

Finally, when the screw 29 inserted into the screw insertion holes 28 and 23 is screwed into the screw hole 18, the tip of the wiring board 22 is
Of the wiring board 22
The contact 22a is pressed into contact with the contact 21c of the thermal head 21, and at the same time, the thermal head 21 and the wiring board 22 are attached to the support plate 16 (see FIG. 2).

And the thermal head / assembly thus assembled
When the unit is attached to a predetermined position of the apparatus body such as a recording device by the positioning feet 19 and the mounting feet 20, the free end of the press-contact portion 30 of the support plate 16 abuts a part of the apparatus body, and the press-contact section
A predetermined pressing force in the direction of the platen is applied to the entire thermal head unit by the reaction force at 30, and the thermal head unit becomes flat when it comes into contact with the platen.

The positioning foot 19 is inserted into a position regulating member such as a roller-shaped platen bearing or a guide pin, and moves along with a thermal head unit installed in the apparatus main body. Or become free.

The mounting foot 20 is a useless one for supporting the thermal head unit, and is mounted on the apparatus body.

When the thermal head 21 and the wiring board 22 and the like are fixed with an adhesive, the protective cover 26 does not participate in the fixing and functions as a head cover and a paper guide.

Further, in the above embodiment, the heat radiating member is constituted by the support plate 16 and the heat radiating sheet 25, but the positioning pins 17, the screw holes 18,
If the positioning feet 19 and the mounting feet 20 can be formed, the heat dissipation member may be formed of a single material having good heat dissipation properties.

(Effects of the Invention) As described above, according to the present invention, the thermal head unit is assembled and installed on the basis of the heat radiation member, the number of components can be reduced, the assembly and maintenance are easy, and the manufacturing cost is reduced. In addition, even if thermal expansion occurs in the heat dissipating member, the displacement between the positioning portion and the mounting portion and the occurrence of rattling are minimized, and as a whole, reliable mounting is performed. ,
A thermal head unit capable of preventing a decrease in print quality can be provided.

[Brief description of the drawings]

1 is an exploded perspective view of a thermal head unit according to an embodiment of the present invention, FIG. 2 is an assembled perspective view of the thermal head unit shown in FIG. 1, and FIG. 3 is a thermal head unit shown in FIG. FIG. 4 is an exploded perspective view of a conventional thermal head unit, and FIG.
The figure is an assembled perspective view of the thermal head unit shown in FIG. 16, 25 ... heat dissipating member, 19 ... positioning part, 20 ... mounting part, 21 ... thermal head, 21b ... heating element, 30 ... pressure contact part.

Claims (1)

(57) [Scope of request for utility model registration] 1. A thermal head unit in which a thermal head for forming an image on recording paper by generating heat from a large number of minute heating elements arranged in a predetermined pattern is attached to a heat radiating member. A pair of opposing positioning portions for performing the operation, and a pair of opposing mounting portions for mounting the thermal head unit to the apparatus body, are integrally formed at both ends in the longitudinal direction of the heat radiating member, A thermal head unit, wherein a pressure contact portion for pressing the thermal head unit in a platen direction is formed integrally with the heat radiating member.