JPS62235151A - Sheet overlapping feed preventing mechanism - Google Patents

Abstract

PURPOSE:To make it possible to surely prevent the overlapping feed of sheets, by providing such an arrangement that when a sheet runs on one of sheet conveying paths, a gate member is rotated toward the other sheet conveying path while an opening and closing piece closes the other sheet conveying path. CONSTITUTION:When a copying button is depressed, a sheet M1 is fed from a cassette 1, and simultaneously with or just after that, when a sheet M2 is inserted into a manual insertion paper feed bed 4, the sheet M1 runs on a first sheet conveying path 3 while it pushes up an opening and closing piece 17a on a gate member 17, and therefore, the opening and closing piece 17a stops the sheet M7 having advanced on a second sheet conveying path 7. Further, when the sheet M1 passes over the opening and closing piece 17a, the gate member 17 is rotated counterclockwise to open the sheet conveying path 7, and therefore, the sheet M2 may initiate running. When the preceding sheet M1 comes to a merging conveyer path 10, the rotation of conveyer rollers is stopped to temporarily stop the running of the sheet M2, and after relieving from the jamming timing, the conveyer rollers are again rotated so that the sheet M2 is conveyed to PS rollers 11, 12, thereby a manual insertion mode is effected.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a paper stack prevention mechanism applied to a paper feed section of an image forming apparatus such as a copying machine.

<Prior art and its drawbacks> In the paper feed section of a copying machine that has a manual paper feed port in addition to a cassette type paper feed port, paper from the manual paper feed port enters and passes through the paper feed section during paper feeding from the cassette. Measures have been taken to prevent this from happening.

FIG. 8 shows an example. That is, in the same figure, there is a first paper conveyance path 3 for the paper drawn out from inside the cassette 1 by the cassette paper feed roller 2, and a first paper conveyance path 3 for the paper drawn out from the cassette 1 by the pair of manual feed rollers 5 and 6 from the manual feed tray 4. The second paper conveyance path 7 is a pair of conveyance rollers 8.
, 9, and any sheet that has reached the merging conveyance path 10 is fed to the PC rollers 1) and 12.

The solenoid 1 is located in front of the manual feed rollers 5 and 6.
3 is provided, and when the paper detection switch 15 on the manual paper feed side detects manual paper during paper feeding from the cassette, the gate 14 closes the second paper conveyance path 7 to remove the paper. This prevents penetration of Instead of opening and closing the second paper conveyance path 7 with the gate 14, when manually fed paper is detected during paper feeding from the cassette as shown in FIG.
Some devices are provided with a clutch 16 that prevents rotation of the manual feed roller 6. These means include the gate 14 and the clutch 16.
In addition, these drive control systems are required, which increases the cost.

For this reason, as shown in FIG. 10, only a paper detection switch 15 is provided on the manual paper feed side, and if this switch 15 is turned on during paper feeding from a cassette, a paper jam is often cleared.

However, with this system, there is a risk that the paper detection switch 15 may be inadvertently turned on when paper is placed on the manual paper feed tray 4, and the paper jam must be cleared each time, which impairs the quality of the copying machine. .

<Object of the Invention> The object of the present invention is to eliminate the above-mentioned drawbacks, and to provide a paper overrunning prevention mechanism that can reliably prevent paper from running through with an hour wheel configuration and maintain the quality of the device. be.

<Structure and Effects of the Invention> The present invention includes first and second paper transport paths that merge with each other at the front, and a transport roller that sends the paper to the front of the merging transport path at the merging point of both paper transport paths. and a gate member having first and second opening/closing pieces for respectively opening and closing the first and second paper transport paths at positions having different distances to the confluence point from one paper transport path. is configured to be rotatable to a position where the other paper conveyance path is closed by an opening/closing piece while the paper is traveling.

According to the present invention, configured as described above,
When paper travels through one paper transport path, the gate member rotates toward the other paper transport path and closes the other paper transport path with the other opening/closing piece. The paper in the paper transport path is stopped until it passes the corresponding opening/closing piece. Therefore, even if sheets are fed simultaneously to both paper conveyance paths, these two sheets can be fed by the conveyance rollers without running through them.

<Embodiment> FIG. 7 is a schematic structural diagram of a copying machine in which the paper stack prevention mechanism according to the present invention is applied to the paper feeding section.

In the figure, a photoreceptor drum 72 is arranged approximately in the center of a copying machine main body 71, and a charger 73 and a developing section 7 are arranged around it.
4. Transfer device 75, cleaner device 76, and static eliminator 7
7th grade is placed. Additionally, a zoom lens 7 that moves horizontally according to the set magnification is mounted above the photoreceptor drum 72.
An optical system 78 including 8a is arranged. Further, on the right side of the photoreceptor drum 72, a paper feed section 82 including upper and lower cassette mounting sections 79 and 80 and a manual paper feed section 81 is arranged.
On the left side, a conveying section 83 for conveying the paper after transfer, a fixing section 84 consisting of a pair of rollers, a paper ejecting section 85, etc. are arranged. The paper in the cassette 86 of the lower cassette mounting section 80 is pulled out by a cassette paper feed roller 87. A third paper conveyance path 88 is provided in front of the paper feed roller 87 on the lower stage side. Paper from the manual paper feed section 81 and the upper cassette mounting section 79
A paper overrunning prevention mechanism A is set for paper from .

FIG. 2 shows the above-mentioned sheet heavy running prevention mechanism A, and the same parts as those of the conventional mechanism are given the same reference numerals and the explanation thereof will be omitted. In the figure, 17 is a gate member for the first and second paper transport paths 3 and 7. This gate member 1
7 is made of synthetic resin or the like, and as shown in FIG. It consists of a second opening/closing piece 17b and a C-shaped shaft hole 17c formed at the other end of the base body 170. In this gate member 17, the C-shaped shaft hole 17C is rotatably fitted to the shaft 2a of the force-centred paper feed roller 2, and the first opening/closing piece 17a is connected to the first paper conveyance path. 3 and the movement of the second opening/closing piece 17b moving back and forth to the second paper conveyance path 7 are in a reciprocal relationship. 9 and the distance a from the entry position of the second opening/closing action piece 17b to the conveying rollers 8 and 9 is set such that a>b.

That is, for example, while paper is being fed from the paper feed cassette 1 as shown in FIG.
The first opening/closing piece 17a is pushed upward in the drawing,
Since the gate member 17 rotates clockwise around the shaft hole 17C, the second opening/closing piece 17b closes the second paper conveyance path 7, and the paper M2 from the manual paper feed tray 4 is prevented from traveling. will be stopped. When the paper M2 passes through the first opening/closing piece 17a and reaches the transport rollers 8, 9, the gate member 17 rotates counterclockwise, so that the paper M2 is transferred to the second paper transport path 7.
travels at a distance of a-b from the paper M1.

Specific paper feeding control of the paper feeding section 82 equipped with the above-mentioned paper heavy running prevention mechanism A will be described below.

(1) When the copying machine is in standby mode, there is no other paper in the copying operation mechanism, so the manual paper feed section 8
When the paper M2 is loaded into the manual paper feed tray 4 of No. 1, the paper M2 is detected by the paper detection switch 15, the manual feed mode is set, and the paper M2 is fed.

(2) When the copy button of the copying machine is pressed, the paper M1 is fed from the cassette 1 of the cassette paper feeding section 79. It is assumed that the paper M2 is loaded into the manual paper feed table 4 immediately after or simultaneously with this cassette paper feeding.

The paper M1 passes through the first paper transport path 3 while pushing up the first opening/closing member 17a of the gate member 17 as shown in FIG. Therefore, the gate member 17 rotates clockwise, and the second opening/closing member 17b stops the paper M2 that has entered the second paper transport path 7. When the paper M1 passes through the first opening/closing piece 17a, the gate member 17 rotates counterclockwise, so the second paper transport path 7 is opened and the paper M2 starts traveling as shown in FIG. do. At this time, the trailing edge of the preceding paper M1 and the leading edge of the paper 2 are a
-b distance is maintained. When the preceding sheet M1 passes through the conveyance rollers 8 and 9 and reaches the combined conveyance path 10 as shown in FIG. 6, the rotation of the conveyance rollers 8 and 9 is stopped to temporarily stop the traveling of the manually fed sheet M2. . Preceding paper M1
When the conveyor roller 8 escapes from the jam timing, the conveyor roller 8
, 9 rotate again, and the paper M2 is conveyed to the ps crawler 1.12, and enters the manual feed mode.

(3) When paper M2 is placed in the manual paper feed tray 4 during cassette multi-feeding, the multi-feeding is interrupted. If the paper M1 fed from the cassette has passed the transport roller 8.9, the manual paper feeding is given priority and the manual feeding mode is set, but the paper M1 fed from the cassette is
While the paper is running in the second paper transport path 3, the operation (2) described above is performed.

When manually fed paper M2 is inserted during cassette paper feeding in this way, if the preceding paper M1 remains on the transport roller 8.9, there is a risk that this paper M1 and the following paper M2 may run through. However, simply providing the gate member 17 prevents both sheets Ml and M2 from passing through, thereby eliminating the need for conventional jam handling and maintaining the quality of the copying machine.

[Brief explanation of drawings]

FIG. 1 is a side view of a gate member in a paper stack prevention mechanism of a copying machine according to an embodiment of the present invention, and FIGS. 2 and 3 are a diagram showing the structure and operation of the paper stack prevention mechanism, respectively. 4 to 6 are explanatory diagrams of the operation of the sheet double running prevention mechanism corresponding to each operation mode of the copying machine, and FIG. 7 is a schematic structural diagram of a copying machine in which the same sheet double running prevention mechanism is implemented. FIGS. 8 to 10 are explanatory diagrams of different conventional paper stack prevention mechanisms. 3-first paper transport path, 7-second paper transport path, 8.9
-! 1) Feed roller, 10 - merging conveyance path, 17 - gate member, 17a - first opening/closing piece, 17b - second opening/closing piece, Ml, M2 - paper.

Claims (1)

[Claims] (1) First and second paper transport paths that merge with each other at the front, and a device that is provided at the junction of the first paper transport path and the second paper transport path and sends the paper forward to the combined transport path. and first and second opening/closing pieces for respectively opening and closing the first and second paper transport paths at positions having different distances to the merging point, A mechanism for preventing heavy paper running, comprising: a gate member configured to be rotatable to a position where the other paper transport path is closed by a corresponding opening/closing piece when the paper is running.