JPH0545488Y2 - - Google Patents

Description

[Detailed explanation of the invention] [Table of Contents] - Overview - Industrial fields of application - Conventional techniques - Problems to be solved by the invention - Means for solving the problems - Actions - Examples Explanation of the mechanism (Part 1 (Fig. 1, Fig. 2) Explanation of functions (Fig. 3) - Effects of the invention [Summary] A paper feeding mechanism that feeds paper by pressing the paper against the platen side using a band-shaped elastic material whose pressure force can be adjusted.

[Industrial application field]

TECHNICAL FIELD The present invention relates to a printer, and particularly to a paper feeding mechanism that feeds paper while pressing the paper against a platen.

[Conventional technology]

A conventional paper feeding mechanism is shown in FIG. A paper guide 21 is arranged outside the platen 20. Axis 2
A pinch roller 22 is provided at the tip of a lever 25 that can pivot about three rotations, and contacts the platen 20 through a hole in the paper guide 21. The pinch roller 22 is pressed toward the platen by a spring 24. 2
6 is a lever for releasing the pressure of the pinch roller 22. The printing paper is inserted along the paper guide 21 in the direction of the arrow, is pressed toward the platen by the pinch roller 22, and is fed by the rotation of the platen.

[Problem that the invention attempts to solve]

In the conventional paper feeding mechanism, since the platen 20 and the pinch roller 22 are in line contact, precision is required for parallelism, and uneven contact may occur. If a large number of pinch rollers 22 are provided in parallel in order to prevent the paper from being fed diagonally due to such uneven contact, the structure will be complicated and the pressure contact force will be uneven. In addition, the pressing force by the spring 24 is concentrated at the contact point between the pinch roller 22 and the platen 20, making it difficult to adjust the pressing force, and when the thickness or number of sheets changes, an appropriate pressing force cannot be obtained. Insufficient pressure may cause the paper to slip, or conversely, too much pressure may cause roller impressions on the paper.
Further, since it is not easy to obtain a uniform pressing force, paper feeding becomes unstable.

The purpose of the present invention is to solve the above-mentioned drawbacks of the prior art,
To provide a paper feeding mechanism for a printer which has a simple structure and can achieve smooth paper feeding by uniformly pressing paper against a platen side with an appropriate pressing force.

[Means for solving problems]

In order to achieve this purpose, in the present invention, an elastic belt stretched between two pulleys is pressed against the platen side, printing paper is sandwiched between the elastic belt and the platen, and one of the two pulleys is To provide a paper feed mechanism for a printer in which at least one position is movable and the contact area between a platen and an elastic belt is variable.

[Effect]

An elastic continuous belt is in surface contact with the platen along an arc of the platen, and the continuous belt presses and feeds the paper toward the platen.

〔Example〕

The configuration of the paper feeding mechanism according to the present invention will be explained using FIGS. 1 and 2. A continuous belt 3 made of an elastic band material such as rubber and stretched between a movable pulley 4 and a fixed pulley 5 is pressed against the platen 1. Print paper 2 is connected to continuous belt 3 and platen 1
It is sandwiched between them and is fed by the rotation of the platen 1.
Both pulleys 4 and 5 may be driven to rotate in synchronization with the platen 1, or may be of an idling type.

When driving, the fixed pulley 5 is used as a driving roller.

In the case of an idling type, it is desirable to provide frictional engagement portions 13 having an appropriate frictional force at both ends of the platen so that the belt is fixed and rotates synchronously with the platen.

When the continuous belt 3 is driven, it is desirable that the continuous belt be brought into an overfeed state at a speed somewhat higher than the circumferential speed of the platen. As a result, smooth paper feeding is achieved when multiple sheets of paper are fed one on top of the other.
In the case of sheet feeding, paper feeding is performed smoothly by making the frictional force on the belt side smaller than that on the platen. The position of the movable pulley 4 can be changed and therefore the contact area between the platen 1 and the continuous belt 3 is variable.

The function when changing the position of the movable pulley 4 is shown in the third section.
This will be explained using figures. The carrier 8 carrying the print head 9 is connected to the guide bar 6 and the drive shaft 7.
supported above. The platen 1 is driven by a motor 10. Reference numeral 11 denotes a paper feeding tractor, and a sprocket 12 engages in a guide hole for continuous paper to feed the paper. When conveying continuous paper using such a tractor 11, the movable pulley 4 of the continuous belt 3 is moved from the dotted line position as shown by arrow A to the solid line position, and the contact area between the continuous belt 3 and the platen 1 is Make smaller. As a result, tractor 1
1 is used to feed the paper, the paper is fed smoothly without being hindered by the frictional force of the continuous belt 3. When feeding printing paper such as a cut sheet without using the sprocket feeding tractor 11, the movable pulley 4 is returned to the dotted line position, and the printing paper is held by the pressure force between the continuous belt 3 and the platen 1, and the platen 1 is rotated. Paper is fed by force.

The position of the movable pulley 4 may be fixed at an arbitrary position, and the contact area of the continuous belt may be adjusted to an optimal state depending on the material, number of printing papers, etc.

In an image printer or the like, when printing figures or the like by slightly moving the printing paper back and forth, the movable pulley 4 is positioned as shown by the solid line, the contact surface of the continuous belt 3 is made small, and the continuous belt 3 is driven. If the printing paper is moved in the front-back direction by the friction between the printing paper and the printing paper, fine paper feeding can be performed accurately regardless of feeding errors due to margins in the sprocket hole of the printing paper or bumps in the gears of the drive motor.

Although the continuous belt in the embodiment was provided over the entire length of the platen, it may be divided into two or several belts.

[Effect of idea]

As explained above, in the paper feeding mechanism according to the present invention, the printing paper is pressed against the platen side using an elastic continuous belt to feed the paper, so the pressing area can be increased and the pressing force can be uniform. Paper can be fed smoothly. Further, by making the pressing area variable, it is possible to always obtain the optimum pressing force depending on the thickness, number, etc. of printing paper.

[Brief explanation of the drawing]

1 and 2 are respectively a front view and a side view of a paper feeding mechanism according to the present invention, FIG. 3 is an explanatory diagram of the operation of the paper feeding mechanism according to the present invention, and FIG. 4 is a side view of a conventional paper feeding mechanism. . 1...Platen, 2...Printing paper, 3...Continuous belt, 4...Movable pulley, 5...Fixed pulley.

Claims (1)

[Scope of utility model registration request] An elastic belt stretched between two pulleys is pressed against the platen side, printing paper is sandwiched between the elastic belt and the platen, and at least one of the two pulleys is movable so that the platen and the elastic belt are moved. Printer paper feed mechanism with variable contact area.