JP3355703B2 - Thermal printer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal printer, and more particularly, to a mechanism for pressing a thermal head against a platen.

[0002]

2. Description of the Related Art In a conventional thermal printer, a mechanism for pressing a thermal head against a platen during printing is shown in FIG.
As shown in FIG. 1, there is a structure in which a spring member 30 is provided between the print head unit 10 and the spring receiving member 20 to press the head. In FIG. 5, the spring receiving member 20 is screwed to the main body frame 40. When the screw 50 is removed, the spring receiving member 20 is removed.
The print head unit 10 is configured to be rotatable in the direction of arrow F, and the thermal head is largely separated from the platen. Since such opening and closing operation of the head is very convenient at the time of paper removal or head cleaning at the time of paper jam, in addition to the method shown in this example, the position of the spring receiving member is locked by using a locking member, Many methods have been proposed, such as releasing the engagement of a spring receiving member and opening a thermal head by operating a lever.

[0003]

An important point of this head pressing mechanism is that the distance d between the thermal head and the spring receiving member is kept constant during printing in order to stabilize the head pressing force. If the distance d is not stable, there is a problem that printing becomes thin or a load becomes too large. As a conventional method of locking the spring receiving member at a predetermined position, a method of locking with a screw as shown in FIG.
The position is difficult to achieve accuracy, and the opening and closing operation of the head requires tools, which makes it difficult to perform. Then, by lever etc.
Although a method of opening and closing the head without using a tool has been invented, there is a problem that the structure is complicated, and therefore, it is difficult to obtain positional accuracy and the cost is easily increased. Therefore, the present invention is to solve such a conventional problem, and the purpose thereof is to easily release the locking of the spring receiving member for the head opening operation,
Further, even if the component accuracy or the mounting accuracy is poor to some extent, a head pressing mechanism capable of stabilizing the head pressing force by maintaining a constant distance between the thermal head and the spring receiving member is provided at low cost. .

[0004]

SUMMARY OF THE INVENTION A thermal printer according to the present invention has the following features. (1) A thermal head attached to a thermal head attachment portion, and a cutter cover containing an auto cutter unit is attached inside the printer cover. The automatic printer unit is built in a printer main body by closing the printer cover, and the thermal head mounting portion is pressed toward the platen by the cutter cover. (2) When the printer cover is closed, the cutter cover presses a projection provided on the thermal head mounting portion.

[0005]

According to the above construction of the present invention, since the spring receiving member can be locked by the movable member, the locking of the spring receiving member can be easily released by changing the position of the movable member. . In addition, since the movable member abuts on the spring receiving member at one point of the protrusion, the distance between the print head portion and the spring receiving member is maintained constant by the positioning member regulating only the positional accuracy of the abutting portion. And the head pressing force can be easily stabilized.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments. FIG. 1 is a sectional view of a line thermal printer according to the present invention, showing a normal printing state. The printer head 4 and the spring receiving member 2
Are rotatably supported by a head support shaft 3 provided at the first position. The spring 5 serves as a roller-shaped platen 6 for the print head 1.
And a plurality of compression coil springs that press against the thermal paper fed and fed to the paper, and are provided at equal intervals in the print line direction between the spring receiving member 2 and the print head unit 1. The spring receiving member 2 is provided with a projection 2a. The printer cover 7 is rotatably supported by a cover support shaft 8 provided on the printer frame 4, and an auto cutter unit (not shown) is mounted inside the printer cover 7.
In order to protect the automatic cutter unit, a cutter cover 7a, which is a pressed part made of sheet metal, is provided. The printer cover 7 is partially bent vertically to form a positioning portion 7b, and the cutter cover 7a is attached to the printer cover 7 in close contact with the positioning portion 7b. When the printer cover 7 is in the position shown in FIG.
The printer cover 7 and the spring receiving member 2 are engaged with each other, and the cutter cover 7a and the protruding portion 2a come into contact with each other.
Is locked in place. At this time, a part of the positioning portion 7b is configured to abut against the cover support shaft 8 provided on the printer frame 4 with high accuracy by the spring force of the spring 5, and is positioned. Therefore, the position of the positioning portion 7b is determined with high accuracy with respect to the printer frame 4, and the position of the cutter cover 7a that is in close contact with the printer frame 4 is determined only by the thickness accuracy of the sheet metal. Decided. At this time, the spring 5 causes the printer cover 7 to move.
A force acts in the direction of arrow A on the printer cover 7, so that a moment in the direction of arrow B acts on the cover support shaft 8 on the printer cover 7, the spring receiving member 2 and the printer cover 7 are stretched, and each of both parts The position is fixed. Therefore, in a normal use state, the printer cover 7 does not rotate in the direction of arrow C and the printer cover does not open. In the embodiment, the cutter cover 7a is described as being attached to the printer cover 7 in close contact with the positioning portion 7b. However, the printer cover 7 can be disposed as shown in FIG. With the spring force of the spring 5, the cutter cover 7a
b, and it is structured to be accurately positioned. In the operation of cutting the thermal paper after printing, the cutter blade 7c built in the printer cover 7 slides in the direction of arrow D, and cuts the thermal paper wound around the platen 6 and fed.

FIG. 2 shows a state in which the operator rotates the printer cover 7 in the direction of arrow C and raises it. In this state, the locking of the spring receiving member 2 is released, and when the operator moves the spring receiving member 2 in the direction of arrow E, the print head 1
Is engaged with the spring receiving member 2, so that the spring receiving member 2
It moves in conjunction with the movement of. In this printer, the operation of opening and closing the head can be performed in this manner, and the removal of paper at the time of paper jam, the cleaning of the head portion, and the like are easy.

FIG. 3 is a plan sectional view of the printer when the head is pressed. A projection 2a is formed substantially at the center of the spring receiving member 2 on the back side of the surface of the spring receiving member 2 that receives the spring 5, and the projection 2a abuts on the cutter cover 7a to lock the spring receiving member 2. are doing. At this time, since the springs are locked substantially at the center, the plurality of springs 5 have the same deflection, and a uniform head pressing force can be obtained in the line direction. In addition, since the positioning portion 7b is disposed near the contact portion and regulates the position of the cutter cover 7a, even if the attachment of the cutter cover 7a is slightly inclined as shown by a dashed line, the spring receiving member 2 is not moved. The locking position does not change. Therefore, the head pressing force is kept constant even if the component accuracy and the mounting accuracy are somewhat poor. That is, in this printer, since the spring receiving member 2 is provided with the projection 2a,
The degree of freedom of the shape of the locking member that locks the spring receiving member 2 is increased, and it is possible to lock the flat portion of the sheet metal member. The cover 7a can be used as a locking member. Although the auto cutter unit is built in the cutter cover 7a, as long as the contact portion with the projection 2a is secured, the cutter cover 7a as the locking member is slightly moved to the left as in the present invention. It is also possible to displace them and dispose the motor 9 on the right side. That is, since the projection 2a of the spring receiving member 2 is located substantially at the center, the center of the spring receiving member can be locked even if the position of the locking member is not necessarily located at the center.

Next, the advantages of the present invention will be described with reference to FIG. FIG. 4 is a plan cross-sectional view of a printer according to the prior art, which is different from FIG. 3 only in two points that a projection is not formed on the spring receiving member 21 and that there is no positioning portion 7b. In this case, since the spring receiving member 21 and the cutter cover 7a abut face to face, the distance between the spring receiving member 21 and the print head unit 1 changes only by slightly inclining the cutter cover 7a as shown in FIG. However, there is a problem that the head pressing force is not stable, and the printing becomes partially thin or the load becomes too large. In addition, since the contact position between the spring receiving member 21 and the cutter cover 7a varies, the turning operation of the printer cover 7 is heavy or light depending on the product, and the operational feeling of opening and closing the head is different. There is also. Therefore, as shown in FIG.
These problems can be solved by providing a configuration in which.

Although the embodiment described above is an example in which the movable member that locks the spring receiving member at a predetermined position is an auto cutter unit, the present invention is not limited to this embodiment. The same applies to the case where the member is a stamp mechanism or when other mechanisms are used, and various layouts are facilitated in designing the printer. In the embodiment, the line thermal printer using the thermal paper as the recording paper has been described. However, the present invention can be applied to a printer using a transfer ribbon.

[0011]

As described above, in the present invention, the degree of freedom of the shape of the movable member is increased, and various mechanisms of a thermal printer such as an auto cutter unit can be used. This has the effect of being easier.

[Brief description of the drawings]

FIG. 1 is a sectional view of a printer according to the present invention (normal printing state).

FIG. 2 is a cross-sectional view of the printer according to the present invention (in a head opening state).

FIG. 3 is a plan sectional view of the printer according to the invention.

FIG. 4 is a plan sectional view of a conventional printer.

FIG. 5 is a sectional view of a conventional printer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Print head part 2 Spring receiving member 2a Projection part 3 Support shaft 4 Printer frame 5 Spring 6 Platen 7 Printer cover 7a Cutter cover 8 Cover support shaft

Claims (2)

(57) [Claims] 1. A thermal printer having a thermal head mounted on a thermal head mounting portion, wherein a cutter cover containing an automatic cutter unit is mounted inside a printer cover, wherein the printer cover is closed. A thermal printer, wherein the automatic cutter unit is built in a printer main body, and the thermal head mounting portion is pressed toward a platen by the cutter cover. 2. When the printer cover is closed,
2. The cutter cover according to claim 1, wherein the cutter cover presses a protrusion provided on the thermal head mounting portion.
The described thermal printer.