JP2935134B2 - Line thermal printer - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small-sized line thermal printer accommodated in various desktop or portable information devices, and more particularly, to a head support for supporting a line thermal head. Regarding the structure.

[Conventional technology]

2. Description of the Related Art A conventional small line thermal printer has been assembled using a frame having a pair of side walls arranged at predetermined intervals in a paper width direction. A platen roller is supported at both ends by the pair of frame side walls. A head support is used to support the line thermal head so that it can be opened and closed with respect to the platen roller. The head support is similarly supported at both ends by a pair of frame side walls.

[Problems to be solved by the invention]

In the conventional line thermal printer described above,
The head support is formed by a so-called die casting method using a mold. However, the die casting method has a problem in that the production cost is increased because an expensive mold is used. Also, it is difficult to form a bearing on the head support itself due to the design of the mold. Therefore, there is a problem that additional parts are required to support the head support to the frame, and the support structure is complicated. Further, there is a problem that the opening / closing mechanism of the head support or the head-up mechanism must be complicated for the same reason.

[Means for solving the problem]

In order to solve the problems or problems of the prior art described above, in the present invention, the head support is formed of a fixed-size extruded product or a pultruded product, and has a bearing groove formed along the paper width direction. Have. On the other hand, a head rotation shaft is supported at both ends between the pair of frame side walls.
The head support is rotatably engaged with the head rotation shaft via an extruded bearing groove, thereby enabling the line thermal head to open and close.

The extruded head support further has a longitudinal groove formed parallel to the bearing groove. A head-up shaft having a head-up roller mounted at one end is rotatably inserted into the longitudinal groove. A head-up member for directly opening and closing the line thermal head by directly acting on the head-up roller is provided on one of the frame side walls.

In addition, a fixing plate is fitted into the frame on the side opposite to the platen roller facing the head support. An elastic member such as a coil spring is mounted between the head support and the fixing plate, and presses the head support against a platen roller.

[Function of the invention]

As described above, in the present invention, the head support is formed of a fixed-size extruded product. Extrusion molding is performed by extruding or drawing a metal material such as aluminum through a die having a predetermined cross-sectional shape. Therefore, the head support can be processed at a lower cost than the conventional die casting method. Also, by using extrusion, a bearing groove along the extrusion direction can be easily formed in the head support. The head support can be directly mounted on the head rotation shaft incorporated in the frame via the bearing groove. At the same time, a longitudinal groove can be formed parallel to the bearing groove. A head-up shaft having a head-up roller mounted at one end is rotatably inserted into the longitudinal groove. The opening and closing operation of the head support can be performed via the head-up roller. Therefore, the mounting structure of the head support to the frame is simplified, and the mounting operation is also facilitated.

〔Example〕

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic plan view of a line thermal printer according to the present invention. As shown, the line thermal printer is incorporated in a frame 1 made of a plastic injection molded product. The frame 1 has a pair of side walls 2 and 3 arranged at predetermined intervals in the paper width direction. As the plastic material, for example, polycarbonate is used. A platen roller 4 is rotatably supported at both ends by the pair of frame side walls 2 and 3. The head support 5 is also rotatably supported at both ends by a pair of frame side walls 2 and 3. The head support 5 supports a line thermal head (not shown) so as to be openable and closable with respect to the platen roller 4. The head support 5 is made of a fixed-size extruded product or a drawn product, and is made of, for example, aluminum. The head support 5 has a bearing groove 6 formed along the paper width direction. On the other hand, a head rotation shaft 7 is supported at both ends between the pair of frame side walls 2 and 3. Head support 5
Are rotatably engaged with the head rotation shaft 7 via the bearing groove 6. As a result, the line thermal head can be opened and closed with respect to the platen roller 4. A longitudinal groove 8 is formed in the head support 5 in parallel with the bearing groove 6. A head-up shaft 9 is rotatably inserted into the longitudinal groove 8. A head-up roller 10 is mounted on one end of the head-up shaft 9. A head-up member 11 is provided on one of the frame side walls 2, and acts on the head-up roller 10 to open and close the line thermal head.

On the opposite side of the platen roller 4 from the head support 5, a fixing plate 12 is fitted into the frame 1. An elastic member 13 composed of a coil spring or the like is mounted between the head support 5 and the fixed plate 12, and presses the head support 5 against the platen roller 4.

FIG. 2 is a central sectional view of the line thermal printer shown in FIG. 1 cut along a paper feeding direction. As shown in the figure, a connection portion indicated by hatching is formed on the inner surface of one frame side wall portion 2, and connects the one frame side wall portion 2 and the other frame side wall portion 3 (not shown) to each other. One end of the rotation shaft of the platen roller 4 is engaged with a notch bearing 14 formed on the frame side wall 2 and is supported by the rotation shaft. Similarly, although not shown, the other end of the rotation shaft of the platen roller 4 is also supported by a notch bearing formed on the other frame side wall 3. Head support 5
Are arranged opposite to the platen roller 4. As described above, the bearing groove 6 is formed in the lower part of the head support 5 made of an extruded product, and the head rotating shaft 7 is inserted through the bearing groove 6. With this structure, the head support 5 is rotatable around the head rotation shaft 7 and performs opening and closing movements with respect to the platen roller 4. Also, the head support 5
A longitudinal groove 8 is formed in the upper part of the head, and a head-up shaft 9 is inserted through the longitudinal groove 8. A head-up roller 10 is mounted on one end of the head-up shaft 9 as described above. This head-up roller 10 is used for the frame side wall 2.
Are arranged so as to be movable along the notch guide portion 15 formed at the center. By operating a head-up member 11 (not shown) to move the head-up roller 10 along the notch guide portion 15, the head support 5 swings about the head rotation shaft 7.

A line thermal head 16 is provided on the front side of the head support 5.
Is attached so that the surface of the platen roller 4 can be contacted. On the other hand, the elastic member 13 is in contact with the back side of the head support 5 as described above, and presses the head support 5 against the platen roller 4.

In the embodiment shown in FIGS. 1 and 2, the line thermal printer has two different paper feed paths. The paper feed path indicated by the arrow C is called a so-called curl path, and supplies the printing paper to a printing unit including a line thermal head while winding the platen roller 4. or,
The paper feeding path indicated by the arrow S is called a so-called straight path, and supplies the printing paper to the printing unit in a substantially straight line.
These two paper feeding paths can be appropriately selected depending on the use of the printer and the type of printing paper. The supplied printing paper is taken out via a common discharge path indicated by arrow D.

Next, with reference to FIGS. 3 (A) and 3 (B), the structure of the head support 5 which is a main part of the present invention will be described in detail. FIG. 3A shows a cross-sectional structure of the head support, and FIG. 3B shows a surface shape of the head support. As shown, the head support 5 is processed by extrusion or pultrusion using a die having a predetermined opening shape. In this extrusion, a metal material in a plastic state, for example, aluminum is pressed and extruded from a die under pressure. The long material extruded in this manner is cut to a fixed size in the width direction of the paper, and FIG. 3 (B)
The head support 5 shown in FIG. By simply setting the cutting dimensions appropriately, it is possible to cope with line thermal printers having different paper width dimensions, and it is possible to significantly reduce parts manufacturing costs. On the other hand, when processing the head support using the die-casting method as in the past, it is necessary to design an expensive mold in accordance with different paper width dimensions, and the manufacturing cost cannot be reduced. Was. Also, by using extrusion molding, the bearing groove 6 and the longitudinal groove 8 can be formed extremely easily. That is, these grooves 6 and 8 extend in the extrusion direction. When the head support 5 having such a structure is incorporated in a line thermal printer frame, the head rotating shaft is simply inserted into the bearing groove 6, and the mounting structure and the mounting operation are greatly simplified. Also, assembly can be performed by simply inserting the head-up shaft into the longitudinal groove 8.

Subsequently, the shape of the fixing plate will be briefly described with reference to FIGS. 4 (A) to 4 (C). 4 (A) is a front view of the fixing plate, FIG. 4 (B) is a plan view of the fixing plate, and FIG. 4 (C) is a cross-sectional view of the fixing plate. As shown, the fixing plate 12 is formed of a metal plate obtained by press working. By appropriately designing the shape, it can be directly fitted into the frame as shown in FIG. Therefore, the mounting operation is simplified without requiring additional components such as screws to fix the fixing plate to the frame as in the related art. As described above, the elastic member 13 is mounted between the fixing plate 12 and the back surface of the head support 5 so as to press the head support 5 against the platen roller 4. As a result, the line thermal head mounted on the front surface side of the head support 5 is pressed against the platen roller to enable an appropriate printing operation.

Finally, the operation of the line thermal printer according to the present invention will be briefly described with reference to FIGS. 5 (A) and 5 (B).
FIG. 5A shows a head-up state, in which the head support 5 is rotated clockwise as indicated by an arrow. In this state, the line thermal head attached to the front side of the head support 5 (indicated by a line segment for simplicity) and the platen roller 4 (not shown) are separated from each other, and the printing paper is inserted and set. The head-up roller 10 attached to the upper part of the head support 5 has a head-up member 11
Is pushed up by the cam surface 17. As a result, the head-up roller 10 moves upward along the notch guide 15 formed in the frame side wall 2, and the head support 5 rotates clockwise about the head rotation shaft 7. . At this time, the head-up roller 10 is
The cam surface 17
And the head-up operation can be performed smoothly. On the other hand, in the conventional structure, a pin is driven into the head support formed by die casting, and the opening / closing operation of the head support is performed via the pin. Therefore, since this pin is fixed and cannot perform a rolling motion, the head opening / closing operation cannot be performed smoothly.

FIG. 5B shows a so-called head down state, in which the line thermal head mounted on the head support 5 and the platen roller are in pressure contact with each other, and a printing operation is performed. In this state, the head-up roller 10 is separated from the cam surface 17 of the head-up member 11 and is located at the bottom of the notch guide 15 by the urging force of an elastic member (not shown).
As a result, the head support 5 is rotated counterclockwise about the head rotation shaft 7. At this time, the switch cam 18 interlocking with the cam surface 17 of the head-up member 11 contacts the open / close switch 19, indicating that the line thermal printer is in a printable state.

〔The invention's effect〕

As described above, according to the present invention, by forming the head support from a fixed-size extruded product, the production cost can be reduced as compared with a conventional die-cast product.

By processing the head support by extrusion, a bearing groove can be formed at the same time, and there is an effect that the bearing structure of the head support can be simplified and the number of parts can be reduced as compared with the related art.

Further, according to the present invention, the head-up roller can be rotatably attached to the head support, and the head-up cam acts on the head-up roller to enable a smoother head-up operation than in the past. effective.

Further, since the fixing plate is directly fitted into the frame in order to support and fix the pressing member to the head support, there is an effect that the assembling work is simplified as compared with the related art.

[Brief description of the drawings]

FIG. 1 is a schematic plan view of a line thermal printer, FIG.
FIG. 3 is a central sectional view of the line thermal printer along the paper feeding direction, FIG. 3A is a sectional view of a head support incorporated in the line thermal printer, and FIG. 3B is a surface view of the same head support. FIG. 4 (A) is a front view of a fixing plate incorporated in the line thermal printer, and FIG. 4 (B).
FIG. 4C is a plan view of the fixing plate, FIG. 4C is a cross-sectional view of the fixing plate, and FIG. 5A is a schematic view for explaining the operation of the line thermal printer, showing a head-up state. FIG. 5B is a schematic diagram for explaining the operation of the line thermal printer and shows a head down state. DESCRIPTION OF SYMBOLS 1 ... Frame 2 ... Frame side wall part 3 ... Frame side wall part 4 ... Platen roller 5 ... Head support body 6 ... Bearing groove 7 ... Head rotating shaft 8 ... Longitudinal groove 9 ... … Head-up shaft 10… Head-up roller 11… Head-up member 12… Fixing plate 13… Elastic member

Claims (2)

(57) [Claims] 1. A frame having a pair of side walls arranged at predetermined intervals in a paper width direction, a platen roller supported at both ends by the pair of side walls, and a line openable and closable with respect to the platen roller. A line thermal printer having a head support for supporting the thermal head, wherein a head rotation shaft is supported at both ends between the pair of side walls, and the head support is formed of a fixed-size extruded product. At one end thereof has a bearing groove formed along the paper width direction, and at the other end thereof has a longitudinal groove formed parallel to the bearing groove, and has the head support through the bearing groove. The line thermal head can be opened and closed by rotatably engaging the body with the head rotating shaft, and a head-up shaft having a head-up roller mounted at one end in the longitudinal groove is rotatable. Is inserted, the line thermal printer on one of the frame side walls, characterized in that the head-up member for performing the opening and closing of the line thermal head by acting on the head-up roller is disposed. 2. A fixing plate fitted to the frame opposite to the platen roller opposite to the head support, and mounted between the head support and the fixing plate to press the head support against the platen roller. 2. The line thermal printer according to claim 1, further comprising an elastic member for performing the operation.