JPH05286201A - Thermal line printer - Google Patents

Abstract

PURPOSE:To easily and uniformly pressure-contact a thermal head heating body line to a platen roller, in a thermal line printer to be used as an output terminal such as a handy terminal and a meter. CONSTITUTION:A protrusion 1a is provided on the central position on a printer main body 1 in a parallel direction with a platen roller 3 and points of action of springs 9a, 9b for pressure-contacting of a thermal head 7 to the platen roller 3 are slid in the direction of the foregoing protrusion 1a. Since a thermal head support member 6 is rockable in all directions on the protrusion 1a as a fulcrum, a thermal head heating body line is pressure-contacted evenly always to the platen roller 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal line printer used as an output terminal such as a handy terminal / measuring instrument.

[0002]

2. Description of the Related Art A thermal line printer of this type is shown in FIG.
As shown in, the platen roller 21 and the thermal head 2
The recording paper 23 is sandwiched between the two, the platen roller 21 is rotated by the motor 24, and the thermal head 22 prints on the recording paper 23. Among them, in the structure in which the thermal head 22 is pressed against the platen roller 21 via the recording paper 23, conventionally, the thermal head support member 26 is rotatably mounted about a shaft 25 mounted parallel to the platen roller shaft. The thermal head 22 is attached to the support member 26, the guide groove 26a of the support member 26 and the bearing 27 rotatably attached to the platen roller shaft are smoothly fitted, and the thermal head support member 26 is attached by the elastic force of the elastic bodies 28a and 28b. The structure is such that the thermal head 22 is pressed and brought into pressure contact with the platen roller 21.
Further, in the structure in which the pressure contact between the platen roller 21 and the thermal head 22 is released when the recording paper 23 is inserted, the lever 30 attached to the printer main body 29 is rotated to push up one end of the thermal head supporting member 26, and the shaft Two
It was rotated about 5 to release the pressure contact.

[0003]

In the conventional structure, the platen roller shaft and the rotary shaft of the thermal head supporting member are separated from each other due to variations in parts / assembling and twist of the printer body when fixing the printer body to the case. When the parallelism is broken, the platen roller and the heating element line of the thermal head fixed to the thermal head supporting member are not pressed uniformly, resulting in problems such as one-sided printing failure. Also, when releasing the pressure contact between the thermal head and the platen roller when inserting the recording paper, etc., one end of the thermal head support member is pushed up while the elastic force for pressure contact is being applied to the thermal head support member. The head supporting member may be deformed, and when the thermal head is pressed against the platen roller again, uniform pressing cannot be obtained, and similarly, defects such as one-sided printing failure occur.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a thermal line printer which can easily realize uniform pressure contact of a platen roller thermal head heating element line.

[0005]

In order to solve the above problems, a thermal line printer according to the present invention is provided with a protrusion at a central position in a direction parallel to a platen roller shaft on a printer main body or a thermal head supporting member, and the thermal head is provided. The support member is attached so as to be swingable in all directions with the projection as a fulcrum.

Further, a hook is provided on the thermal head support member, the thermal head is attached so that the tip of the elastic body that is in pressure contact with the platen roller hangs on the hook, and the elastic body is rotatably and pushes the elastic body during rotation. A rotating body having a different radius of rotation for releasing the elastic force of the elastic body from the thermal head supporting member is attached to the printer body.

[0007]

According to the present invention, the positions of both ends of the platen roller shaft are prevented due to variations in the position of the bearing portion provided on the side surface of the printer main body for axially supporting the platen roller, twisting of the printer main body when mounting the printer main body, and the like. Even if it is misaligned, the thermal head support member can be swung in all directions around the protrusion attached to the center rear part, so that the heating line of the thermal head is uniformly pressed along the platen roller. Become.

Further, when the pressure contact between the thermal head and the platen roller is released, the elastic body pressing the thermal head against the platen roller is pushed by the rotating body rotatably attached to the printer main body and having a difference in the rotation radius. The elastic force of the elastic body is released from the thermal head support member, and then the elastic body detaches the thermal head from the platen roller by lifting the hook on the thermal head support member. Since the thermal head supporting member is released from the head supporting member, the thermal head supporting member is not deformed, and the thermal head heating element line is uniformly pressed against the platen roller even in the case of re-pressing.

[0009]

Embodiments of the present invention will be described below with reference to FIGS. FIG. 1 is a perspective view showing the overall configuration of a printer according to an embodiment of the present invention, and FIGS. 2 and 3 are partial cross-sectional views of a thermal head pressure contact portion of the printer.

In the figure, reference numeral 1 is a printer main body, and rotatably supports a platen roller 3 at both ends thereof via bearings 2. Further, the driving force of the motor 4 attached to the printer body 1 is transmitted by the gears 5a and 5b to rotate the platen roller 3. Further, the thermal head 7 fixed to the thermal head supporting member 6 having the groove 6a fitted with the bearing 2 and the hooks 6b and 6c is attached to the recording paper 8.
While being pressed against the platen roller 3 through the one end, one end thereof is hooked on the hooks 6b and 6c on the thermal head supporting member 6, and elastic force is exerted at a position apart from the contact point of the heating element line 7a of the thermal head and the platen roller 3 by A. The springs 9a and 9b are arranged so that Further, in the printer body 1, a shaft 11 which is rotated by a lever 10 and has a different radius of rotation by cutting off a part of the circumference has springs 9a, 9a.
It is provided so as to penetrate between b and the thermal head support member 6. A protrusion 1a is provided at a central position of the printer body 1 in a direction parallel to the platen roller shaft.
It receives the rear part of the thermal head support member 6.

The operation of the thermal line printer configured as described above will be described with reference to FIGS. First, the pressing operation of the thermal head 7 against the platen roller 3 will be described with reference to FIGS. The thermal head support member 6 to which the thermal head 7 is fixed has contact points at one contact point X with the projection 1a and a contact line between the platen roller 3 and the thermal head heating element line 7a, and is pressed against the platen roller 3. Springs 9a, 9b for
The point of action Y is displaced from the contact point of the heating element line 7a of the thermal head and the platen roller 3 by A in the direction of the protrusion 1a, so that the point X, the platen roller 3 and the thermal head heating element line 7a are always pressed. Will be supported by the contact line with. Further, as shown in FIG. 3, a similar operation is performed by providing a protrusion 6d on the thermal head support member 6 at a central position in a direction parallel to the platen roller 3 and receiving the protrusion 6d by the printer body 1.

The operation for releasing the pressure contact between the platen roller 3 and the thermal head 7 is as shown in FIGS.
It shows in (c). First, in the state of FIG. 2A, the platen roller 3 and the thermal head 7 are in pressure contact, and the lever 11 of FIG.
When the springs 9a and 9b are pushed up, the elastic force of the springs 9a and 9b is increased as shown in FIG. 2 (b).
Is released from. When the shaft 11 is further rotated, the springs 9a and 9b are pushed up, and at the same time, one ends of the springs 9a and 9b are caught by the hooks 6b and 6c on the thermal head supporting member 6, and the thermal head supporting member 6 is lifted.
The thermal head 7 is separated from the platen roller 3 (FIG. 2 (c)).

As described above, according to the present embodiment, the support member 6 to which the thermal head 7 is fixed can be swung in all directions around the point X, and the printer can be mounted on the parts and the assembly variation or the case. Due to the twisting of the printer body 1 when fixing, both end bearings 2 of the platen roller 3
Even if the position is deviated, the thermal head support member 6 swings so that the thermal head 7 follows the platen roller 3, and the thermal head heating element line 7a and the platen roller 3 are pressed uniformly.

When the thermal head 7 and the platen roller 3 are released from the pressure contact when the recording paper 8 is inserted, the elastic force of the springs 9a and 9b is received by the shaft 11.
No elastic force acts on the thermal head supporting member 6, so that the thermal head supporting member 6 is not deformed, and the thermal head heating element line 7a is evenly pressed against the platen roller 3 even in the case of re-pressing. Will be. In the present embodiment, the rotating body for pushing up the springs 9a and 9b is the shaft 11 with a part of the circumference cut, but the rotating body is not limited to the shaft, but may be an L-shaped plate or a part of the circumference. The same effect can be obtained also in a rotating body such as a cam-shaped shaft having a protrusion that causes a difference in radius when rotating.

[0015]

As described above, according to the present invention, since the thermal head supporting member swings in all directions around a single point, the thermal head heating element line can always be pressed uniformly against the platen roller. .. Further, since the elastic force does not act on the thermal head supporting member when the pressure contact is released, it is possible to prevent the thermal head supporting member from being deformed and improve the printing quality.

[Brief description of drawings]

FIG. 1 is a perspective view showing the overall configuration of a thermal line printer according to an embodiment of the present invention.

2 (a), (b) and (c) are partial cross-sectional views showing the operation of thermal head pressure contact / pressure contact release according to an embodiment of the present invention.

FIG. 3 is a partial sectional view showing a structure of a thermal head pressure contact according to an embodiment of the present invention.

FIG. 4 is a perspective view showing the overall configuration of a conventional thermal line printer.

[Explanation of symbols]

 1 Printer body 1a Protrusion 2 Bearing 3 Platen roller 4 Motor 5a, 5b Gear 6 Thermal head support member 6a Guide groove 6b, 6c Hook 6d Protrusion 7 Thermal head 7a Thermal head heating element line 8 Recording paper 9a, 9b Spring 10 Lever 11 Shaft

Claims (4)

[Claims] 1. A printer main body in which a platen roller is rotatably supported by bearings provided on both sides, a drive unit for rotating the platen roller, and a platen roller shaft of the platen roller rotatably attached. Bearings,
A platen roller shaft on the printer body having a thermal head support member having a groove that fits with the bearing, and an elastic body that presses a line type thermal head attached to the thermal head support member against the platen roller. A thermal line printer, wherein a protrusion is provided at a central position in a direction parallel to the thermal head support member, and the thermal head support member is swingably attached with the protrusion as a fulcrum. 2. A thermal head support member is provided with a protrusion at a central position in a direction parallel to the platen roller shaft, and the thermal head support member is swingably attached with the protrusion as a fulcrum. The thermal line printer described. 3. The point of action of an elastic body that presses the thermal head against the platen roller is moved in the protruding direction from the contact point between the heating element line of the thermal head and the platen roller. Thermal line printer. 4. A bearing rotatably mounted on a platen roller shaft, a thermal head support member having a groove for fitting with the bearing and fixing a line type thermal head and having a hook, and the thermal head. An elastic body attached so that the head support member is pressed against the platen roller and the tip thereof is hooked on the hook of the thermal head support member when the pressure contact is released; and an elastic body that pushes the elastic body during rotation to elastically move the elastic body from the thermal head support member. A thermal line printer, comprising: a rotating body that releases a force and that is attached to a printer body and that has a difference in a rotation radius.