JPH0473173A - Pressure roller mechanism of printer - Google Patents

Abstract

PURPOSE:To obtain a convenient and simple mechanism for opening and closing pressure rollers by providing a first and a second cam surface for causing a second pressure roller support to rotate when a first pressure roller support rotates against the force of a torsion spring. CONSTITUTION:When a release shaft 8 rotates freely in the direction of the arrow A, since by the force of a torsion spring 7 a rear pressure roller support 5 is moved in the direction of the arrow B and a front pressure roller support 6 is moved in the direction of the arrow C, a rear pressure roller 3 and a front pressure roller 4 contacts a platen 1 and the tension of the torsion spring 7 is transmitted to the platen 1. When a release shaft 1 rotates in the direction of the arrow D, a roller support 5 moves in the direction of the arrow E and the cam surface 14 of the roller support 5 rotates in the direction of the arrow D to push the cam surface 15 of the roller support 6, so that the roller support 6 rotates in the direction of the arrow F. For this reason, clearances between the platen 1, a roller 3 and a roller 4 are made larger.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a pressure roller mechanism for pressing paper against a platen in a printing device.

[Conventional technology]

Conventionally, the pressure roller mechanism of this type of printing device includes a pressure plate 11 and a base, in which a pressure spring 10 for applying tension to the pressure roller 3.4 is attached to a release shaft 8, as shown in FIGS. 3 and 4. A guide 13 is attached to the base frame 12, which is provided between the frames and guides a pressure roller support to which the rear and front pressure rollers 3.4 are attached. In FIG. 3, when the release shaft is free to rotate in the direction of arrow G, the pressure plate 11 moves in the direction of arrow H due to the force of the breather spring 10, and is applied to the platen 1 via the pressure roller support 9 to the rear and front pressure rollers 3.4. are in contact with each other, and the tension of the pressure spring 10 is the same as that of the rear and front pressure rollers 3.
, 4 to the platen. In FIG. 4, when the release shaft 8 rotates in the direction of arrow 1, the pressure plate 11 moves in the direction of arrow J, and the pressure roller support 9
moves in the direction of arrow J due to the weight of the rear and front pressure rollers 3 and 4, and the gap between the platen 1 and the rear and front pressure rollers 3 and 4 is opened. Note that 2 in FIGS. 3 and 4 is a vapor guide.

[Problem to be solved by the invention]

In the pressure roller mechanism of the conventional printing device mentioned above,
The pressure roller support has a one-piece structure and must have a base frame for mounting the pressure spring and guiding the pressure roller support, resulting in a complicated structure.

[Means to solve the problem]

The pressure roller mechanism of the printing device of the present invention includes a release shaft, a first pressure roller support that rotates integrally with the release shaft, and a first pressure roller support that is coaxially and rotatably supported with the first pressure roller support. two pressure roller supports, each supporting the first pressure roller support;
and a second pressure roller support, each of which is supported by a first and second pressure roller;
and a torsion spring that acts to rotate the first and second pressure roller supports in the direction in which the second pressure roller is pressed against the platen; first and second cam surfaces not provided on the first and second pressure roller supports that cause the second pressure roller support to also rotate against the torsion spring when the pressure roller support rotates; There is.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a side sectional view of the pressure roller mechanism of the printing device of the present invention when the pressure roller is closed.

A paper guide 2 that guides the paper is disposed below the platen 1 that serves as a printing surface and feeds the paper, and the rear pressure roller 3 and front pressure roller 4 that feed the paper are independently suspended by a rear pressure roller support 5 and a paper guide 2 that guides the paper, respectively. It is attached to the front pressure roller support 6. The rear pressure roller support 5 is interlocked with the release shaft 8, and the front pressure roller support 6 is coaxial with the rear pressure roller support 5 but rotates freely.
A torsion spring 7 is provided to apply tension to the front pressure roller 4. Cam surfaces 14 and 15 are also provided on the rear pressure roller support 5 and the front pressure roller support 6 to ensure clearance between the platen 1, the rear pressure roller 3, and the front pressure roller 4.

To explain the operation in Fig. 1, when the release shaft 8 is free to rotate in the direction of arrow A, the force of the torsion spring 7 causes the rear pressure roller support 5 to move in the direction of arrow B, and the front pressure roller support 6 to move in the direction of arrow C. By moving, the rear pressure roller 3 and the front pressure roller 4 come into contact with the platen 1, and the tension of the torsion spring 7 is transmitted to the platen 1.

FIG. 2 is a side sectional view of the pressure roller mechanism of this embodiment when the pressure roller is open. Release shaft 1
rotates in the direction of the arrow, the rear pressure roller support 5 moves in the direction of the arrow E, the cam surface 14 of the rear pressure roller support 5 rotates in the direction of the arrow, pushes the cam surface 15 of the front pressure roller support 6, and the front Pressure roller support 6 rotates in the direction of arrow F. Therefore, there is a gap between the platen 1, the rear pressure roller 3, and the front pressure roller 4.

〔Effect of the invention〕

As explained above, in the present invention, among the independently suspended first and second pressure roller supports, the first pressure roller support is interlocked with the release shaft, the second pressure roller support has a degree of freedom, and the second pressure roller support has a degree of freedom. The first pressure roller support is coaxially supported, and a torsion spring that applies a load to the pressure roller is mounted thereon, and the first pressure roller support, which is interlocked with the release shaft, rotates in a direction that opens the gap between the platen and the pressure roller. Then, since the second pressure roller support also has a cam surface on itself that moves in the direction of opening the gap between the platen and the pressure roller, a simple and easy pressure roller opening/closing mechanism can be achieved.

A side sectional view of one embodiment of the mechanism when the pressure roller is closed,
Fig. 2 is a side sectional view of the embodiment shown in Fig. 1 when the pre-pressure roller is open, Fig. 3 is a side sectional view of the pressure roller mechanism of the conventional printing device when the pressure roller is closed, and Fig. 4 is FIG. 4 is a side sectional view of the pressure roller mechanism of the conventional printing device shown in FIG. 3 when the pressure roller is open;

1...Platen, 2...Paper guide, 3...
Rear pressure roller, 4... Front pressure roller, 5... Rear pressure roller support, 6...
・Front pressure roller support, 7... Torsion spring, 8... Release shaft, 9...
Pressure roller support, 10...Pressure spring, 11...Pressure plate, 12...Base frame, 14.15...Cam surface.

Claims (1)

[Claims] a release shaft; a first pressure roller support that rotates together with the release shaft;
a second pressure roller support that is coaxially and rotatably supported with the pressure roller support; first and second pressure rollers that are each supported pivotally on the first and second pressure roller supports, respectively;
a torsion spring that acts to rotate the first and second pressure roller supports in the direction in which the first and second pressure rollers are pressed against the platen; and a torsion spring that acts against the torsion spring by rotation of the release shaft. first and second cam surfaces provided on the first and second pressure roller supports that cause the second pressure roller support to also rotate against the torsion spring when the first pressure roller support rotates; A pressure roller mechanism of a printing device characterized by comprising: