JP2650381B2 - Paper feed mechanism - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a sheet feeding mechanism, and more particularly to a sheet feeding mechanism of a printing apparatus using an electrophotographic system.

[Conventional technology]

3 and 4 show a conventional laser printer type paper feeding mechanism. As shown in FIG. 3, after loading the paper 1 in the tractor 10, the switch 14 is pressed down. Then, the tractor 10 is rotated by the motor 6, and the paper 1 passes between the photosensitive drum 2 and the retractor 3 which is separated from the photosensitive drum 2. Thereafter, the leading end of the sheet 1 passes through the conveyor belt 4 and the fixing unit 11 and reaches the puller 12. Further, the paper 1 is stacked on the stacker 13 by the pulling force of the puller 12.
Until it is ready for printing.

In this paper feeding mechanism, when the leading edge of the paper 1 passes between the photosensitive drum 2 and the retractor 3 when the paper is loaded, if the leading edge of the paper 1 is not bent, the paper 1 passes as shown at 1-a in FIG. However, if the leading end of the sheet 1 is bent upward, the sheet 1 may enter between the photosensitive drum 2 and the paper guide 5 as shown at 1-b in FIG. Become.

As a method of solving the above problem, there is a method of changing the shape of the paper guide 5 to the shape of a two-dot chain line in FIG. 4. However, in this case, the flash light from the fixing unit 11 (see FIG. 3) is used. There is a disadvantage that the irradiation amount of the 15 photosensitive drums 2 increases and the life of the photosensitive drums 2 is shortened.

[Problems to be solved by the invention]

In the above prior art, since the shape of the paper guide 5 is changed, the irradiation amount of the flash light 15 from the fixing unit 11 to the photosensitive drum 2 is increased, the life of the photosensitive drum 2 is shortened, and the reliability of paper loading is reduced. There was a problem of doing.

The object of the present invention is to eliminate the above-mentioned disadvantages of the prior art,
An object of the present invention is to provide a sheet feeding mechanism capable of improving the reliability of sheet loading.

[Means for solving the problem]

When the paper is loaded, the retractor is held between the holding position for printing and the holding position for non-printing.

[Action]

When the paper is loaded, the retractor is held between the holding position during printing and the holding position during non-printing by the retractor motor, so that the paper traveling direction changes and the paper guide contacts the paper guide or between the photosensitive drum and the paper guide. No more intrusion.

〔Example〕

Hereinafter, an embodiment of the present invention will be described in detail with reference to FIGS.

FIG. 1 is a configuration diagram showing one embodiment of a paper feeding mechanism of the present invention. In FIG. 1, the retractor 3 has a gap of 0.5 mm with the photosensitive drum 2 shown in FIG.
It is held at the position indicated by the dashed line, and the gap with the photosensitive drum 2 is held at the position indicated by the solid line of 3.5 mm during non-printing. The retractor motor 8 is a stepping motor,
The printing position is set in 12 steps (1 step 15 °) from the non-printing position.

By the way, when loading paper, the switch 14 (see FIG. 3)
Is pressed down, the retractor motor 8 rotates by 8 steps, and the retractor 3 moves the photosensitive drum 2 from the non-printing position.
The gap with is moved to about 1.2mm and held. This state is shown in FIG. Therefore, when the leading end of the paper 1 passes over the opening of the retractor 3, it strikes the photosensitive drum 2 and changes its traveling direction, so that the paper 1 comes into contact with the paper guide 5 or
It does not enter between the photosensitive drum 2 and the paper guide 5, passes over the conveyor belt 4,
It is sent to the stacker 13 through the stacker 12 (see FIG. 3) and the shape of the paper guide 5 does not need to be changed. Therefore, the life of the photosensitive drum 2 is not shortened.

After the paper is loaded, the retractor 3 returns to the non-printing position, and is ready for printing.

〔The invention's effect〕

As described above, according to the present invention, since the retractor can be held between the non-printing position and the printing position when the paper is loaded, there is an effect that the reliability of paper loading can be improved.

[Brief description of the drawings]

FIG. 1 is a structural view showing an embodiment of a paper feeding mechanism of the present invention, FIG. 2 is a view showing a state when paper is loaded in FIG. 1, and FIG. 3 is a configuration of a paper feeding mechanism of a conventional laser printer. FIG. 4 is an enlarged view of the vicinity of the photosensitive drum in FIG. 1 is a paper, 2 is a photosensitive drum, 3 is a retractor, 4 is a transport belt, 5 is a paper guide, 7 is an eccentric shaft, 8 is a retractor motor, 9 is a transfer unit, 10 is a tractor, 12 is a puller, and 14 is a switch.

Continuation of front page (56) References JP-A-57-124764 (JP, A) JP-A-63-231962 (JP, A)

Claims (1)

(57) [Claims] 1. A printing apparatus using an electrophotographic method, comprising: at least a pair of tractors that engage feed holes along both side edges of continuous form paper and convey the paper; A retractor mechanism for transferring the toner image on the photosensitive drum onto the paper sheet, a puller for pulling the paper sheet, and a paper guide for assisting the transport of the paper sheet. A sheet feeding mechanism comprising: means for holding the retractor between a holding position during printing and a holding position during non-printing when the sheet is loaded.