JP2002264374A - Thermal printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mechanism capable of adjusting an offset of a thermal head printer by a simple structure in a thermal printer. SOLUTION: An offset adjusting plate 20 is attached to a head holder 22 holding the thermal head 30 such that the fixing position can be adjusted. As the offset adjusting plate 20 is engaged with a projection 24a of a head plate 24 having the thermal head 30 attached thereto, when the attachment position of the offset adjusting plate 20 is changed in the vertical direction, the attachment angle of the head plate 24 is changed. When the attachment position of the head plate 24, the contact angle of the thermal head 30 with a platen roller 12 is changed so that adjusting of the offset can be carried out.

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 thermal head offset adjustment and a head pressure adjustment mechanism.

[0002]

2. Description of the Related Art Thermal printers for printing by pressing a thermal head against a platen roller are widely used. As disclosed in Japanese Patent Application Laid-Open No. 10-86421, the optimal offset position at which the heating element of the thermal head contacts the platen roller differs depending on the sheet thickness. A mechanism is provided. In a printer capable of using papers having different widths, a mechanism is provided for adjusting the head pressure by changing the stroke of a compression spring for applying a pressing force to the head.

[0003]

However, in the conventional offset adjusting mechanism, since the thermal head is moved back and forth, a U-shaped part having the length of the head width is required. There is. In order to adjust the head pressure to an appropriate value, a component for adjusting the amount of deflection of the compression spring is required.

[0004]

In order to achieve the above-mentioned object, the present invention provides a recording head by pressing a thermal head, which can be pressed against and separated from a platen roller, to the platen roller via recording paper. In the printer, a plate to which the thermal head is attached and a fixing plate that can be attached by changing the attachment angle of the plate are provided.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, a stepping motor 15 is mounted on a motor plate 16. A control board 17 is attached to the motor plate 16. Platen roller 12 for transporting recording paper
Is rotatably attached to the paper guide 11 with an E retaining ring 19 via a bearing 18. A gear 13 is fixedly attached to the platen roller 12, and the rotational force of the stepping motor 15 is reduced by the reduction gear 14.
, And then transmitted to the gear 13 to drive the platen roller 12. The paper guide 11 is attached to the motor plate 16 with screws.

[0006] The thermal head 30 is
It is screwed to. An L-shaped hook is formed on the front surface of the head plate 24, and the head holder 2
2 is configured to be positioned and held in the left-right direction by a notch provided on the front surface of the second member. The thermal head 30 is mounted on the head holder 22 with the platen roller 1.
A leaf spring 25 for pressing to 2 is attached with screws 27.28. A lever 23 for opening and closing the head is mounted on the right side surface of the head holder 22. A paper guide 26 is provided under the thermal head 30 with a screw 2
9 attached to the head holder 22.
The head holder 22 has an offset adjusting plate 20 with a screw 2
It is attached with 1. An opening is provided at the center of the offset adjusting plate 20, and a convex portion 24a formed on the head plate 24 is fitted to the opening. Further, a long hole for screwing is formed in the offset adjusting plate 20, and the fixing position can be adjusted by the long hole.

As shown in FIG. 2, the platen driving section 3 and the head holding section 2 are rotatably supported by a shaft 31 so that the head holding section 2 is rotatable. It is hung across the drive unit 3 and the head holding unit 2 and is attached by the E retaining ring 33.34.35. Therefore, when the lever 23 is operated, the head holding unit 2 can be opened around the shaft 31. it can.

Next, a method of adjusting the offset will be described. The head holder 22 includes an offset adjustment plate 20.
Are provided so that the fixed position can be adjusted, and the offset adjusting plate 20 and the convex portion 24a of the head plate 24 are engaged with each other. The mounting angle also changes. When the mounting angle of the head plate 24 changes, the contact angle between the thermal head 30 and the platen roller 12 can be changed. As described above, by changing the contact angle between the thermal head and the platen roller, the same effect as in the case where the position of the thermal head is moved back and forth and adjusted can be obtained.

The adjustment mechanism when a narrow sheet is used will be described. When printing using narrow paper, the width adjustment is performed by moving the guide provided on the right side in accordance with the width of the paper with reference to the left side of the paper guide 11 in FIG. I have. When narrow paper is used, the thermal head 30 is tilted to the side without paper (right side), and printing on the left end of the paper is blurred. Then, by loosening the screw 28 to which the right leaf spring 25 is attached, the thermal head 30 is removed.
The pressure on the right side of can be reduced. When the right head pressure is reduced, the thermal head 30 is moved to the platen roller 1.
2 can be made horizontal, so that print blur at the edge of the paper can be prevented.

[0010]

According to the structure of the present invention, even if the optimum offset position of the thermal head with respect to the platen roller changes according to the thickness of the paper, the offset can be adjusted with a simple structure, and the deterioration of print quality can be prevented. . The head pressure can be adjusted by loosening the screw to which the leaf spring is attached, so that the head pressure can be adjusted without increasing the number of components.

[Brief description of the drawings]

FIG. 1 is an exploded view of the present invention as viewed from a paper discharge side.

FIG. 2 is a perspective view of the present invention as viewed from a sheet discharge side.

FIG. 3 is an external view of the present invention as viewed from a sheet insertion side.

[Explanation of symbols]

 12 platen roller 20 offset adjustment plate 22 head holder 24 head plate 25 leaf spring

Claims (2)

[Claims] 1. A printer which performs recording by pressing a thermal head provided so as to be able to contact and separate from a platen roller with the platen roller via recording paper,
A plate on which the thermal head is mounted,
A thermal printer, comprising: a fixing plate that can be mounted by changing a mounting angle of the plate. 2. A printer which performs recording by pressing a thermal head provided so as to be able to press and separate from a platen roller to said platen roller via a recording paper,
The leaf spring that presses and presses the thermal head is fixed with screws,
A thermal printer, characterized in that the pressing force on the thermal head is adjusted by turning the screw.