JPS63315439A - Paper conveyor - Google Patents

Abstract

PURPOSE:To remedy the skewing feed of paper without fail by installing a control device which rotates a conveyor roller as long as the specified prolonging time since a tip of the paper has arrived at a resist roller. CONSTITUTION:A fact that paper has been fed to a conveyor roller 2 is detected by a paper detecting switch 6, and when the paper is being fed to a resist roller 1 by the conveyor roller 2, a paper detecting switch 7 in an extension part of the conveyor roller 2 is turned on. And, after the specified time since this detecting switch 7 has been turned on, the conveyor roller 2 stops its rotation, having the paper bent to some extent and it straightens the paper tip. However, when the paper has no length, in so much that it is bent between rollers, the conveyor roller 2 is rotated in succession, and the paper tip is straightened by microvibration due to the rotation. The paper whose tip is straightened is fed to a sensitizer drum 8 and, after a transfer precess is executed, it is reconveyed by a suction roller 9.

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to an electrostatic transfer copying machine and a laser printer.

The present invention relates to a device that reliably corrects skewed feeding of paper in paper conveyance devices such as ADFs, sorters, and RDHs.

<Prior Art> As is well known, a paper conveyance device such as a copying machine includes a conveyance roller and a registration roller that aligns the leading edge of the paper conveyed by the conveyance roller and then feeds the paper. Copy paper or the like is slightly bent between the transport roller and the registration roller, and skewed feeding of the paper is corrected by the stiffness of the paper itself.

<Problems to be Solved by the Invention> However, in the case of special paper with a small margin, the total length of the paper is too long for the pitch between the conveyance roller and the registration roller. It is not possible to provide the necessary amount of deflection to correct the leading edge of the paper.

Therefore, since such short sheets of paper are fed diagonally and then fed directly to the photosensitive drum in the copying machine, there is a problem in that copies are made diagonally with respect to the paper.

Means for Solving the Problems> The present invention provides a paper transport device comprising a transport roller and a registration roller that aligns the leading edge of the paper transported by the transport roller and feeds the trailing paper. ,
The apparatus further includes a control means for rotating the transport roller for a predetermined extended period of time after the leading edge of the paper reaches the registration roller when the length of the paper is shorter than the distance between the transport roller and the registration roller.

With this configuration, according to the paper conveyance device according to the present invention, when the paper size is small, the conveyance roller continues to rotate for a while after the leading edge of the paper reaches the registration roller, thereby causing the Slight vibrations are applied to the trailing edge of the paper by a pair of rotating transport rollers.

As a result, the entire paper is corrected, the paper is correctly aligned, and skewed feeding of the paper is prevented.

<Example> Hereinafter, the configuration of the present invention will be described with reference to the drawings.

FIG. 1 is a structural diagram of a paper conveyance device according to an embodiment of the present invention, and is provided with a conveyance path as shown.

In the same figure, l is a registration roller (PS roller:
(PS stands for paper stop), and the registration roller 1 serves to temporarily stop the paper and align the leading edge of the paper.

Further, a conveyance roller (PF crawler - PF means <-feed) 2 is provided apart from the registration roller 1 at a predetermined pitch interval.

The conveyance roller 2 transports the paper to the registration roller 1v.
c It works to send out.

The paper fed to the registration roller 1 is
The paper is supplied from the manual paper feed section 3 or the paper feed power center 4.

That is, the manual paper feed section 3 is provided with a manual paper feed roller 3a and a reversing roller 3b, which face each other and are in contact with each other.
The operator feeds the paper manually to the transport roller 2. Further, above the paper feed cassette 4, a conveyance roller 4 is provided.
a + 4 b are provided to send out the paper stored in the paper feed cassette 4 toward the transport roller 2 . In this embodiment, since the paper feed cassettes 4 are provided in multiple stages, the lower paper feed cassette 4 is equipped with a transport roller 5 for supplying the paper fed from the paper feed cassette 4 to the transport roller 2. It is set up.

As described above, the paper fed by each roller passes through each path and is all sent to the transport roller 2.

Then, the paper detection switch 6 detects that the paper has been sent to the transport roller 2, and furthermore, when the paper is sent to the registration roller 1 by the transport roller 2, an extension of the transport roller 2 The paper detection switch 7 located at is turned on. Then, after a certain period of time after the paper detection switch 7 is turned on, the conveyance roller 2
stops rotating, bends the paper, and straightens the leading edge of the paper.

However, when the paper is not long enough to bend between the rollers, the conveyance roller 2 is continuously rotated,
The leading edge of the paper is corrected by slight vibrations caused by the rotation.

The paper whose leading edge has been corrected is supplied to the photosensitive drum 8, subjected to a known copying process, and then conveyed again by the suction roller 9.

Note that the rotation (stopping) of the registration roller 1 is synchronized with the rotation (stopping) of the photosensitive drum 8, so that the leading edges of the original and copy paper are aligned.

FIG. 2 is a flowchart showing the processing contents of the paper conveyance device of this embodiment.

In the figure, PFC1 is a paper feed clutch, and PFC2 is a clutch that operates a conveyance roller (hereinafter referred to as a conveyance latch). Each roller of the paper feed system shown in FIG. 1 is operated by the paper feed clutch. Further, as shown in FIG. 1, a paper detection switch 6 is provided in the middle of paper conveyance, and a paper detection switch 7 for registration is provided in front of the registration roller I.

This flowchart shows paper feeding control up to the registration roller 1.

First, when the print switch (not shown) is turned on and paper can be fed, the paper feed clutch PFI and transport latch PF2 are turned on (step n1), and the paper detection switch 6 is turned on. wait for.

Then, when the paper detection switch 6 is turned on, the paper feed clutch PFI is turned to 0FFL (nz step) and then the process waits for the paper detection switch 7 to be turned on.

When the paper detection switch 7 is turned on, the paper size N (
(longitudinal size) and the distance between the registration roller l and the transport roller 2 (hereinafter referred to as inter-roller distance) As a result of the above comparison, if N≧X, as before, the fixed time t
Set ms in the timer TPF (ns step). On the other hand, if N<X, the timer TP is the time tms plus a predetermined extension time α (tms+αゝ)
Set to F (rz step).

When the time set in the timer TPF has elapsed, the transport latch PF2 is turned off (ns step)0.As mentioned above, if the paper size N is greater than or equal to the distance between the rollers When the paper reaches the roller 1, the paper is still urged in the feeding direction by the rotation of the transport roller 20, so that the paper is appropriately bent in front of the registration roller 1.

On the other hand, if the paper size N is less than the inter-roller distance X, the paper leaves the transport roller 2 before the set time elapses, but the The transport roller 2 applies a slight vibration to the trailing edge of the paper, thereby correcting the skewed feeding of the paper.

In addition, in the case of NCX, the trailing edge of the paper is
Even if the paper is not bitten by the paper, as long as it is long enough to be in contact with the transport roller 2, it is possible to prevent the paper from being fed diagonally.

As mentioned above, in the case of paper with a small longitudinal size, by lengthening the time until the conveyance roller 2 stops after reaching the registration roller 1, the trailing edge of the paper is free from the rotational force of the conveyance roller 2. A slight vibration is generated, and the entire sheet is corrected by the slight vibration, and skewed feeding of the paper is avoided.

Note that the paper size requires at least a length such that the leading edge of the paper contacts the registration roller 1 and the rear end of the paper contacts the transport roller 2.

FIG. 3 shows a block diagram of the control circuit of the paper conveyance device of this embodiment.

The microcomputer IO performs control according to a control program stored in advance in a ROM (read only memory) 11, and a RAM (random access memory) 12, which stores buffer memory and flags. Used as an area for other calculations.

13 is a key switch and the paper detection switch 6.
7 and the like, and 14 is the signal input device 1.
This is an interface (Ilo) circuit for 3.

In addition, 15 digit copy magnification display and other display circuits 15
a and each load 15b of the clutch PFI, PF2, etc.
16 is its interface (Ilo> circuit).

Effect> As described above, according to the paper conveyance device according to the present invention, when conveying paper with a small longitudinal size, the conveyance roller is lengthened by a predetermined extension time when the paper direction is corrected before the registration roller. By rotating, a slight vibration is applied to the trailing edge of the paper, thereby reliably correcting the skewed feeding of the paper, and dramatically stabilizing the performance of the paper conveyance unit.

[Brief explanation of the drawing]

FIG. 1 is a structural diagram of a paper conveying device according to an embodiment of the present invention;
FIG. 2 is a flowchart showing the processing contents of the paper transport device, and FIG. 3 is a block diagram of a control circuit of the paper transport device. l... Registration roller, 2... Conveyance roller. 3...Manual paper feed section, 4...Paper feed cassette. 6...Paper detection switch, 7...Paper detection switch. Agent: Patent attorney Takeshi Sugiyama (and 1 other person) Figure 2

Claims (1)

[Scope of Claims] 1. A paper conveyance device comprising a conveyance roller and a registration roller that aligns the leading edge of the paper conveyed by the conveyance roller and then feeds the paper, the conveyance roller and the Paper transport characterized by comprising a control means for rotating the transport roller for a predetermined extended time after the leading edge of the paper reaches the registration roller when the length of the paper is shorter than the interval between the registration rollers. Device.