JPH05318876A - Thermal line printer - Google Patents

Abstract

PURPOSE:To make it easy to uniformly weld with pressure a thermal head heat generating line to a platen roller, in a thermal line printer to be used as an output terminal. equipment of a handy terminal measuring instrument. CONSTITUTION:A protrusion 1a is provided at a central position parallel with a platen roller 3 on a printer body 1 and a nearly L-shaped protruding piece 12 to which the protrusion 1a butts is provided on a thermal head support member 6. Thus, the thermal head support member 6 can rock in all directions with the supporting point at the protrusion 1a, so that a thermal head heat generating line is welded with pressure to the platen roller 3 always uniformly.

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 This type of thermal line printer 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, The head supporting member is provided with a substantially L-shaped protruding piece that abuts on the protrusion and swingably supports the thermal head supporting member.

[0006]

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.

[0007]

1 is a perspective view showing the overall construction of a printer according to an embodiment of the present invention.

In the figure, reference numeral 1 is a printer main body, and rotatably supports a platen roller 3 via bearings 2 at both ends thereof. 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. A projecting piece 12 having a substantially L-shape is provided at the rear portion of the thermal head supporting member 6, and a projection 1a abuts a surface 12a of the projecting piece 12 which is substantially parallel to the thermal head supporting member 6 to support the thermal head. The member 6 is swingably supported.

The operation of the thermal line printer configured as described above will be described with reference to FIG. First, the pressing operation of the thermal head 7 against the platen roller 3 will be described with reference to FIG. 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. Since the point of action Y of the springs 9a and 9b is displaced from the contact point between the heating element line 7a of the thermal head and the platen roller 3 by A in the direction of the protrusion 1a, the point X and the platen roller 3 are always contacted during pressure contact. It is supported by the contact line with the thermal head heating element line 7a.

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 any direction around the point X, and the printer can be mounted on the parts and the assembly 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.

[0013]

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, the thermal head supporting member is provided with a substantially L-shaped projecting piece, and a projection is brought into contact with the projecting piece to swingably support the thermal head supporting member. Since it is bent in the shape of a letter, the height of the printer can be reduced by that amount, and the overall size can be reduced.

[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 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 12 protruding piece

Claims (1)

[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 protrusion is provided at a central position in a direction parallel to the thermal head supporting member, and the thermal head supporting member is provided with a substantially L-shaped protruding piece that abuts against the protrusion and swingably supports the thermal head supporting member. Thermal line printer.