JPH0286472A - Paper feeding mechanism for printer - Google Patents

Abstract

PURPOSE:To enable a stable feeding pitch for cut papers to be obtained despite variations in the thickness of the cut papers or variations in environmental conditions by varying forces for pressing a pressure roller against a platen, at a multiplicity of levels. CONSTITUTION:At the time of feeding a cut paper, a feeding pitch for the cut paper varies according to the thickness of the paper. The variations in the feeding pitch is compensated for by regulating forces for pressing a pressure roller 3 against a platen 1 through driving a pulse motor 10. Effects of temperature can also be obviated similarly.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a paper feeding mechanism of a printing device.

[Conventional technology]

In conventional printing devices that feed paper using frictional force between a circular platen and a pressure roller, the pressing force of the pressure roller against the platen was not variable.

FIGS. 4 and 5 are cross-sectional views showing a conventional paper feeding mechanism. The pressure roller 3 is pressed against the platen 1 by the spring 5, and the cut sheet 11 is pressed against the platen 1.
(Figure 4). pressure roller 3
The pressing force is released by rotating the cam 6b and retracting the arm 4 (FIG. 5).

[Problem to be solved by the invention]

In the conventional paper feeding mechanism described above, the pressure roller presses against the platen with a constant force, so the difference between the platen and the pressure roller due to differences in the thickness of the cut paper or differences in environmental conditions (temperature, humidity, etc.) The drawback was that the frictional force changed and the feeding pitch of the slip paper was unstable and varied.

[Means to solve the problem]

The paper feeding mechanism of the printing device of the present invention is a printing device that feeds paper by frictional force between a circular platen and a pressure roller, and includes an arm that supports the pressure roller, a spring for pressing the pressure roller against the circular platen, and a spring that presses the pressure roller against the circular platen. A cam for steplessly retracting the pressure roller from the platen via an arm, a pulse motor for rotating the cam, and one to a plurality of transmission members for transmitting rotation of the pulse motor to the cam. have

〔Example〕

Next, an embodiment of the present invention will be described with reference to the drawings.

1 to 3 are cross-sectional views of one embodiment of the present invention. The pressure roller 3 is supported by the tip of the arm 4 and is pressed toward the platen 1 by a spring. The arm 4 rotates steplessly by the rotation of the cam 6a, and the pressure roller 3 can be retracted from the platen 1. cam 6
The rotation of a is performed by a pulse motor 10 via a gear 7, a gear 8, and a motor gear 9.

When feeding the cut sheet 11, the feeding pitch of the cut sheet 11 changes depending on whether, for example, thick paper is fed or thin paper is fed. By driving, it is compensated for by changing it in multiple stages (-stage is one pulse of the pulse motor 10).

The effects of temperature can also be avoided in the same way.

〔Effect of the invention〕

As explained above, in the present invention, the force applied by the pressure roller to the platen is changed in multiple stages, so that the pressure roller can be pressed against the platen stably even against differences in the thickness of paper sheets or differences in environmental conditions. This has the effect of providing the feeding pitch of the cut sheet.

[Brief explanation of drawings]

FIGS. 1 to 3 are cross-sectional views showing one embodiment of the present invention, and FIG.
1 and 5 are sectional views showing a conventional mechanism. ■...Platen, 2...Paper guide, 3...Pressure roller, 4...Arm, 5...Spring, 6a... ...Cam, 6b...Cam, 7...Gear, 8.
...Gear, 9...Motor gear, 10...
...Pulse motor, 11...Slip paper. Agent Patent Attorney Susumu Uchihara

Claims (1)

[Claims] In a printing device that feeds paper by friction between a circular platen and a pressure roller, an arm supports the pressure roller, a spring presses the pressure roller against the circular platen, and the pressure roller is moved from the platen via the arm. 1. A paper feeding mechanism for a printing device, comprising: a cam for retracting in multiple stages; a pulse motor for rotating the cam; and a transmission member for transmitting rotation of the pulse motor to the cam.