JPH0259095B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a registration device for feeding a sheet of paper to a moving body such as a photoreceptor in synchronization with the moving body in an electrophotographic copying machine or the like.

As a conventional registration device, one shown in FIG. 1 is known.

That is, the uppermost sheet 1' of the stacked sheets 1 in the sheet cassette is conveyed by the sheet feed roller 2 to the registration roller 3, and enters the nip between the registration roller 3 and the registration pinch roller 4, which are in a stationary state.

At this time, since the paper 1' is suddenly stopped, it becomes bulged (hereinafter referred to as a buckle) between the registration roller 3 and the paper feed roller 2.

After correcting the paper skew so that the image on the photosensitive drum 5 is parallel to the paper 1', the registration roller 3 is moved by a mechanism such as a clutch at the timing when the image on the photosensitive drum 5 and the registration match. The sheet 1' is rotated and conveyed toward the photosensitive drum 5.

In order to correct paper skew in such a registration device, the lead edge of the paper is corrected by creating a buckle in the paper.
must rest along the nip between the registration roller 3 and the registration pinch roller 4.

However, since the nip between the registration roller 3 and the registration pinch roller 4 is wedge-shaped and has some elasticity, if the lead edge of the paper 1' is strongly caught in the nip, the skew correction of the paper 1' can be corrected. may not be done enough.

Furthermore, the registration roller 3 must be kept stationary and must be driven intermittently, requiring a complicated and expensive mechanism such as a clutch.

The present invention has been made in view of the above circumstances, and its purpose is to provide a registration device that can reliably correct paper skew, reduce variations in registration, and furthermore, has a simple mechanism and is inexpensive. It is to provide.

Embodiments of the present invention will be described below with reference to FIGS. 2 and 3.

Note that members that are the same as those in the prior art have the same reference numerals.

A registration gate 6 is provided between the paper feed roller 2 and the registration roller 3, and the registration gate 6 consists of a base portion 6a fixed to a rotating shaft 7 and an abutment portion 6b. As shown in FIG. 3, a plurality of them are provided on the rotating shaft 7.

Then, when rotating the rotating shaft 7 clockwise, the second
The skew correction position is shown as a solid line in the figure, and when rotated counterclockwise, the release position is shown as a dotted line in the second figure.

Note that 8 is a pair of upper and lower guides, and the guide 8 has a contact portion 6b of the registration gate 6.
A notch (not shown) is formed through which it faces.

Next, the operation will be explained.

The registration roller 3 is constantly rotating at the same speed as the photosensitive drum 5 (or at a slightly higher speed).

Then, the top paper 1' is sent out by the paper feed roller 2 and reaches the registration gate 6 located at the solid line position.
A buckle is created by contacting the contact portion 6b of the contact portion 6b.

In this state, the paper feed roller 2 stops, the paper 1' becomes stationary, and the paper skew is corrected.

That is, when the paper 1' is fed with its lead edge slanted due to a difference in the feeding force between the left and right paper feed rollers 2, a part of the lead edge comes into contact with the contact portion 6b of the registration gate 6. After that, the paper is fed diagonally using the contact portion between a part of the lead edge and the contact portion 6b of the registration gate 6 as a fulcrum, and the entire lead edge touches the contact portion 6b of the registration gate 6. The paper skew is corrected by uniform contact, and then the paper is fed further, creating a buckle and causing the paper feed roller 2 to
stops.

Next, at the timing when the image on the photosensitive drum 5 and the registration match, the registration gate 6 is moved to a release position shown by a dotted line by a mechanism such as a solenoid (not shown).

For this reason, the paper 1' has a buckling force (restoring force)
Then, the paper 1' protrudes by a length corresponding to the size of the buckle, and the lead edge of the paper 1' is pressed against the nip between the registration roller 3 and the registration pinch roller 4, and is caught and moved toward the photosensitive drum 5. transported.

Here, if the paper has very high rigidity (for example, paper such as official postcards), even if the lead edge of the paper hits the contact portion 6b of the registration gate 6, the paper feed roller 2 will not create a buckle. It may spin idly on the paper 1' and may not be able to create a sufficient buckle.

In this way, if a sufficient buckle is not created, the paper protrusion length will be shortened when the registration gate 6 is in the release position, and the lead edge of the paper will be pushed between the registration roller 3 and the registration pinch roller. Paper 1' cannot be fed out without reaching nip 4, resulting in a paper jam.

Therefore, in the present invention, slightly before the registration gate 6 starts moving to the release position (for example, 10 to
30mmsec) to the release position, then move the paper feed roller 2 for a short period of time (for example, 50mmsec to 100mmsec).
I made it rotate.

By doing this, even if the paper is not sufficiently bundled, the paper feeding force of the paper feed roller 2 can reliably feed it into the nip between the registration roller 3 and the registration pinch roller 4, thereby preventing paper jams. do not have.

Note that rotating the paper feed roller 2 as described above can be easily carried out by using a timer or the like, so a detailed structure will be omitted.

As described above, the present invention corrects paper skew by bringing the paper lead edge into contact with the registration gate 6, so that the paper skew can be corrected reliably.

Further, since the registration roller 3 is constantly driven to rotate, there is no need to provide a mechanism for intermittent driving as in the prior art, resulting in a simple structure and low cost.

In addition, since the paper feed roller 2 is driven from a time slightly earlier than when the registration gate 6 starts moving to the release position and continues after the registration roller 6 moves to the release position, the registration gate 6 is moved to the release position. A feeding force is applied to the paper slightly before it moves to the release position, and when it moves to the release position, it is fed out by the restoring force of the buckle 6 and the feeding force, so even if the paper is too rigid and does not form enough buckles, the lead edge of the paper can be kept in the register. The paper can be reliably fed into the nip between the registration roller 3 and the registration pinch roller 4, and can be reliably conveyed without causing a paper jam.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a conventional example, FIG. 2 is an explanatory diagram showing an embodiment of the present invention, and FIG. 3 is a perspective view of a registration gate. 1 is paper, 2 is paper feed roller, 3 is registration, 4 is registration pinch roller,
6 is the registration gate.

Claims (1)

[Scope of Claims] 1. A registration roller 3 and a registration pinch roller 4 are disposed in pressure contact with each other on the paper feeding side of the paper feeding roller 2, and the paper is fed into the nip thereof. A registration gate 6 is provided between the paper roller 2 and the nip so as to be movable between a skew correction position where it interferes with the lead edge of the paper and an open position where it is separated from the lead edge of the paper, and the registration gate 6 is in the release position. The registration device is characterized in that it is provided with a control means for driving the paper feed roller 2 from a time slightly earlier than the time when the registration gate 6 starts moving to the release position until after the registration gate 6 has moved to the release position.