JPS62234966A - Paper feed apparatus - Google Patents

Abstract

PURPOSE:To enable a stable paper feed, by providing a pressing force variable means capable of making the pressing force of a press means variable. CONSTITUTION:Paper 5 is held between a press means 21 and a roller 20 under pressure by operating the press means 21 to be frictionally supported. When the paper 5 is fed, a rotary solenoid is operated by turning a start switch ON to shake an eccentric cam 22 to a direction reducing the spring force of a compression spring 21b and, next, a motor is rotated and a rear part tractor 8 begins to run to a feed direction. Whereupon, proper back tension is applied to the paper 5 by the pressing force of the roller 21 and the press means 21 and the paper 5 is successively printed without collapsing the perforations of the paper and slacking said paper.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a paper conveyance device such as a line printer device that prints and discharges continuous folded paper.

[Conventional technology]

FIG. 2 is a schematic diagram of a general conventional electrophotographic printing device such as a line printer device that prints and discharges continuous folded paper.

As an example of a printing device with such a configuration,
There is No. 0-117171. In the figure, the configuration will be explained according to the printing process. First, a latent image is formed on the photosensitive drum 111 by the latent image forming means (2). Next, the developing means (31) supplies developer powder to the photosensitive drum +11.
The latent image formed above is visualized. Next, transfer means A4
1, the entire visible image on the photoreceptor drum is transferred to the paper (6). Developing powder remaining on the photosensitive drum (1) after transfer is removed by a cleaning brush (6). On the other hand, the paper (6) is sequentially pulled out by the hopper (Ill) and conveyed to the roller mechanism (7) and the transfer means 14. and,
The visible image formed on the photoreceptor drum by the transfer means (4) is transferred to the paper (61).Then, the rear tractor (8)
1. After being sent to the heat fixing device (9) and heat-fixed, it is sent to the stacker Kasumi and folded.

Next, paper loading and operation will be explained. Release the paper holding plate (12J). Next, operate the pressing means (7a) yk to release the pressure on the roller (7b), allowing the paper (5) to pass through the gap created, and at the same time press the photosensitive drum +11. and the transfer means (4), load the paper feed hole into the protrusion of the rear tractor (8), and close the paper presser plate (1).Next, operate the pressing means (7a) to transfer the paper (6). ) with the roller (7b) and apply pressure 7
+7 support.

When the motor rotates and the rear tractor (8) begins to travel in the transport direction, appropriate pack tension is applied to the paper +51 by the pressure of the roller (7b) and the pressing means (7a), and the paper (6) is printed one after another without sagging. Ru.

Once printing has finished, if printing is continued again with the same paper set, if the paper continues to run and print, the inertia of the drive system will prevent printing until it reaches a certain speed, so the end of printing will occur. A blank space appears at the beginning. In order to minimize this margin, the paper is made to run slightly backwards in advance.

At this time, since the rotational force of the tractor is transmitted to the roller (7b), the paper is sent back to the ice brim side.

[Problem that the invention seeks to solve]

In conventional devices, the pressure of the pressing means of the roller mechanism is always constant, so when feeding the paper in the paper transport direction, the back tension force is sufficient to prevent the paper feeding hole of the paper from being crushed by the paper transport protrusion of the rear tractor. (that is, the pressing force against the roller) or less. This needs to be set even smaller if the paper thickness becomes thinner. However, during reverse running and standby, if there is not enough conveyance force to convey the paper back by the tractor without sagging, the paper may come into contact with the photoreceptor drum and become dirty. This is because thick paper is stiff and tends to bend on the paper path if the conveyance force is not sufficient.
is greatly needed. In other words, this invention has problems such as the inner cone is used to set a constant pressing force suitable for the back tension force in the sheet conveying direction and the pressing force as the conveying force during reverse running. This was done to solve these problems, and it has two types: one is the pressing force that acts as the pack tension force in the conveying direction, which is easily influenced by the paper path shape, seven tractions, and the thickness of the paper, and the other is the pressing force that is the conveying force during reverse travel. It takes a lot of time to adjust the pressing force to suit both. The purpose is to obtain a printing device that does not require .

[Means for solving problems]

The paper conveyance device according to the present invention includes a tractor having a conveyance protrusion that engages with a paper feed hole of the printing paper at the rear part across the printing section and conveys the printing paper, and a roller that transports the printing paper at the front part. In a paper conveying device equipped with a roller mechanism that applies pressure between pressing means, does not rotate in the paper transport direction but rotates only when traveling in reverse, and applies pack tension to the paper, the pressing force of the pressing means is A pressure variable means is provided so that the pressure can be varied in the paper conveyance direction and during reverse travel.

[Effect]

The variable pressure means in this invention sets the pressure of the pressure means at an appropriate pressure that does not cause collapse of the paper feed hole during conveyance of the paper, and when the paper is conveyed in the reverse direction, even if the paper is thick, it is exposed to light due to the curvature of the paper. Contact M with the body drum! It is easy to set the push force necessary for the conveyance force sufficient to prevent ll- 1-1, independently, and stable conveyance can be achieved.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

In Fig. 1, (8) is a rear tractor that transports the paper (5) from the hopper to the stacker, 02) is a paper holding plate that holds the paper (5) between the rear tractor and prevents it from rising;
is a roller that is pivoted so that it does not rotate in the paper transport direction (direction of arrow A), but only in the opposite direction, @υ is a roller that holds the paper (5) between it and applies full pressure. It is a pressing means and has a structure that allows it to apply and release pressure. (ZXa) is a rotatably supported pressing roller, (gtb) is a compression spring that applies pressure to the shaft of the pressing roller (lla), and (21c) is a compression spring (g
A compression spring (g) is attached to the shaft (gxa) in the direction of arrow B so as to be in contact with the eccentric cam (to), which is a lever that supports the pressure roller (gla) k and is a pressure variable means via the pressure roller (g).
o+) is pivoted with a greater force.

To release the pressure on the roller, the shaft (ald)
This is done by operating a lever (not shown) provided at one end of the . Further, the eccentric cam @ is connected to the compression spring (
By varying the amount of deflection of the press roller (21LL), the pressing force of the press roller (21LL) against the roller is changed, and the press roller (21LL) is electrically oscillated by a rotary lenoid (not shown).

Next, paper loading and operation will be explained. Release the paper presser plate 0. Next, by operating the pressing means (2I and releasing the pressure on LOW and 9@), the paper (6) is passed through the created gap, and at the same time the photosensitive drum +1
1 and the transfer means (41), and transfer the rear tractor (
Load the paper feed hole into the protrusion 8), close the temporary paper presser mold, and then operate the pressing means @11 to sandwich the paper (6) between the rollers and apply pressure to support it by friction.

When transporting paper, turn on the start switch and
The rotary lenoid works to compress the eccentric cam with the compression spring (gi).
When the motor is rotated and the rear tractor (8) begins to move in the conveying direction, the paper (5) is swung in the direction in which the spring force of b) is reduced.
Appropriate back tension is applied to the paper (5), and the paper (5) is printed one after another without collapsing the holes or sagging. Once printing has been completed, the state of the paper set continues and if printing is performed again, the inertial force of the drive system will prevent printing until it reaches a certain speed. , margins appear at the end and start of printing. In order to minimize this margin, it is necessary to run the paper slightly backwards in advance.

At this time, the rotary lenoid works and swings the eccentric cam 4 in the direction where the spring force of the compression spring (gtb) increases.
Next, the motor rotates, and an appropriate tension is applied to the paper (5) due to the difference between the pressing force of the roller and the pressing means αυ and the roller speed slightly faster than the tractor speed, so that the paper (6) does not sag and therefore There is no contact with the drum, and it can be moved backwards to a fixed position without getting dirty.

In the above embodiment, a roller is shown as the pressing means, but a plate spring or the like may also be used.

In addition, although an eccentric cam and a rotary lenoid are used as the pressure variable means, the same effect can be obtained by driving the push/pull lever with a motor or other solenoid to swing the lever and change the amount of deflection of the spring. Effects can be obtained.

〔Effect of the invention〕

As described above, according to the present invention, since the variable pressure means is provided which can vary the pressure of the pressure means, it is possible to set the pressure to an appropriate level that does not cause paper feed hole deviation during paper transport, and to adjust the thickness of the paper during reverse transport. Even if the paper is thick, it can be easily adjusted independently to set the pressure necessary to prevent the photoreceptor from coming into contact with the photoreceptor due to the curvature of the paper, allowing stable transport.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional side view showing the entire sheet conveying device according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of an electrophotographic printing apparatus including a conventional sheet conveying device. In the figure, (11 is the photosensitive drum, 14) is the transfer means, (6) is the paper, (7) is the front tractor, (8) is the rear tractor, (12!J is the paper presser plate, the handle is the rotor, ■υ
is the pressing means, cl! ! is a pressure variable means. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] A tractor with a printing part sandwiched between the rear part and a conveying protrusion that engages with a paper feed hole of the printing paper to transport the printing paper, and a front part that applies pressure by sandwiching the printing paper between a roller and a pressing means. In a paper conveyance device equipped with a back tension roller mechanism that does not rotate in the paper conveyance direction but rotates only during reverse conveyance, the conveyance speed of the roller is slightly faster than the conveyance speed of the tractor. A paper conveyance device characterized by comprising a pressure variable means arranged so that the pressure force of the pressure means can be varied in the paper conveyance direction and in the reverse direction.