JP2566253B2 - Paper feeder - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a calling roller that presses and rotates on an upper surface of a sheet in a sheet stacking section to feed a sheet, and a pair of sheet feeding rollers and a torque limiter downstream of the feeding roller. The present invention relates to a paper feeding device having a reversing roller having a built-in roller.

2. Description of the Related Art Conventionally, a sheet feeding device of such a sheet feeding method has been widely used in various copying machines and printers.

In these paper feeding devices, when the stacked sheets are double-fed by the calling rollers into the cassette as the sheet stacking unit, the reverse rollers provided on the downstream side of the feeding are reversely rotated. Only the lower side of the multi-fed sheet is returned to the cassette again, but at that time, the sheet is returned too much and rises once to make it easier to return the sheet. is there.

In such a case, even if you try to re-feed the returned paper, you will not be able to do it again.Therefore, in order to prevent this paper from being returned too much, the rear edge of the cassette that regulates the paper return position is generally used. A presser foot and a rear end fence are provided.

As a sheet feeding device having such a trailing edge presser, for example, there is one as shown in FIG. 5. In this sheet feeding device, the leading end portion of the sheets stacked in the cassette 1 is attached to a not shown striking plate. While abutting, both ends of the sheet are position-regulated by the left and right side fences 21 and 22, respectively, and an arm 23 rotatably supported on the upper rear end of the side fence 21 so as to be rotatable in the arrow A direction. Chain attached to the tip 24
Thus, the position of the sheet is regulated by pressing the rear end portion of the sheet returned in the arrow G direction by the reverse rotation roller 4.

When using sheets of different sizes, the arm 23 is moved in the direction of arrow A to change the position of the chain 24.

However, in the case of such a conventional paper feeding device, when the paper in the cassette is replaced with a paper of a different size or the paper is replenished, there is a trailing edge presser or a trailing edge fence, so that the replacement or the replenishment work is not possible. It ’s hard to do,
If the sheet is misaligned and set, there is a problem in that a set failure of the sheet may occur.

Further, since the trailing edge presser and the trailing edge fence are attached to the cassette, the total length of the cassette is correspondingly lengthened, and the sheet feeding device is accordingly increased in size, resulting in an increase in cost.

The present invention has been made in view of the above problems, and prevents excessive returning of sheets when the sheets are double-fed without providing a trailing edge presser or a trailing edge fence in the sheet stacking portion. It is an object of the present invention to provide a compact paper feeding device which can be operated and is excellent in operability when exchanging paper.

To achieve the above object, the present invention includes a calling roller that presses and rotates the upper surface of the paper in the paper stacking unit to feed the paper, and a pair of paper feeding rollers and a torque limiter on the downstream side of the feeding of the calling roller. In a paper feeding device having a built-in reversing roller, even when the calling roller releases the above-mentioned paper at a position upstream of the above-mentioned calling roller of an elevating member that presses or releases the above-mentioned calling roller against the upper surface of the paper. A paper pressing member is attached so as to press the upper surface of the paper.

Hereinafter, a specific description will be given based on an embodiment of the present invention.

FIG. 1 is a schematic configuration diagram showing an example in which the present invention is applied to a paper feeding device of a plain paper copying machine, and FIG. 2 is a plan sectional view of the same.

In this paper feeding device, a calling roller 2 that press-rotates the upper surface of the sheet stacked in a cassette 1 that is a sheet stacking portion and feeds the sheet in the direction of arrow B in FIG. A pair of paper feed rollers 3 and a reversing roller 4 incorporating a torque limiter, which will be described later, are provided on the downstream side of the feeding.

Then, the pressing arm 6 is rotatably supported in the direction of arrow C in FIG. 1 by the calling arm 5 which rotatably supports the calling roller 2 to press or release the press contact with the upper surface of the sheet. A pressing roller 7 as a paper pressing member is rotatably mounted at a position upstream of the calling roller 2 of the pressing arm 6 so as to press the upper surface of the paper even when the calling roller 2 releases the pressure contact of the paper.

The calling arm 5 has a U-shaped cross section and has side surfaces 5a and 5b at both ends. The feed shaft 8 is rotatably supported by penetrating the feed shaft 8 through the side surfaces 5a and 5b.
A shaft 9 is fixed in parallel to the feed shaft 8 on the upstream side (right side in FIG. 1) of the paper feeding roller 3, and the paper feeding roller 3 in which the rubber portion 3a is integrally fitted to the outer peripheral portion as shown in FIG. The calling roller 2 fixed to one end of the feed shaft 8 and having the rubber portion 2a integrally fitted on the outer peripheral portion is rotatably attached to the shaft 9.

Further, a support shaft 11 is fixed to the side surface 5a approximately in the middle of the feed shaft 8 and the shaft 9 so as to be parallel to the feed shaft 8 and the shaft 9, and the tip end of the support shaft 11 (right in FIG. 2). In addition, for example, a pressing arm 6 rotatably supporting a pressing roller 7 made of rubber on a shaft 10 is rotatably supported, and the pressing arm 6 has a circular arc shape around the center of the feed shaft 8 at the center thereof. Arcuate hole 6a (first
(See also the drawing) is formed, and the large diameter portion 9a of the shaft 9 is slidably fitted into the arcuate hole 6a.

Then, as shown in FIG. 2, the side surface of the calling arm 5
A drive gear 12 fixed to the feed shaft 8 and the shaft 9 between the feeding roller 3 and the feeding roller 3a and a gear 13 integrally formed with the central member of the calling roller 2 are rotatable on the support shaft 11. The feed roller 3 is engaged by an idle gear 14 pivotally supported on the feed roller 3 by a motor (not shown) connected to the end of the feed shaft 8 opposite to the feed roller 3 (upper side in FIG. 2). The calling roller 2 is adapted to rotate in the direction of arrow D in FIG.

The calling arm 5 rotates about the feed shaft 8 in the direction of arrow E in FIG. 1 via a lever that swings by the operation of a calling solenoid of a lifting device (not shown). Press it against the top of the paper,
The pressure contact is released.

Next, the torque limiter 20 built in the reverse rotation roller 4 will be described with reference to FIG.

The torque limiter 20 disconnects or connects the reverse rotation shaft 15 that constantly rotates in the direction opposite to the paper feed roller 3 by the torque transmitted from the paper feed roller 3 to the reverse rotation roller 4. .

The structure is such that a cylindrical member 16 with a collar having a spring receiver 16a is integrally fitted to the reverse rotation shaft 15, and a clutch ring 17 having a spring receiver 17a is integrally fitted to the reverse rotation roller 4 via a bearing 19. And a coil spring 18 is engaged between the spring receivers 16a and 17a.

The coil spring 18 is formed on the outer peripheral surface 17 of the clutch ring 17.
It is set so as to be in close contact with and integral with b, and is fitted slightly more loosely than the outer peripheral surface 17b on the outer peripheral surface 16b of the flanged cylindrical member 16 so that a slip occurs between them at a predetermined torque or more. There is.

Therefore, when a torque equal to or higher than a predetermined torque is applied to the reverse rotation roller 4 from the paper feed roller 3, the reverse rotation roller 4 and the reverse rotation shaft 15 are uncoupled, and the reverse rotation roller 4 rotates in the normal direction. 4 and the reverse rotation shaft 15 are connected via a clutch ring 17, a coil spring 18, and a cylindrical member 16 with a collar, and the reverse rotation roller 4 reversely rotates in the direction of arrow F in FIG.

Next, the operation of this embodiment thus configured will be described.

When there is no paper in the cassette 1 shown in FIG. 1 and the calling arm 5 is also lowered by an elevating device (not shown), the right ends of the calling arm 5 and the pressing arm 6 are the feed shaft 8 and the support shaft 11 respectively. It rotates about the center and is positioned lower than the illustrated position.

When a sheet bundle of sheets P is put in the cassette 1 and pushed up by a sheet raising mechanism (not shown), the pressing roller 7 and the calling roller 2 come into contact with the upper surface of the uppermost sheet at substantially the same time,
The pressing roller 7 lightly presses the upper surface of the sheet by its own weight with the shaft 10 and the pressing arm 6.

At this time, the calling roller 2 has a shaft 9 that supports it.
The large diameter portion 9a of the holding arm 6 can move in the arcuate hole 6a of the holding arm 6, so that it can move up and down as necessary,
In the state shown in FIG. 1, the rubber portion 2a (FIG. 2) is pressed against the upper surface of the sheet P at a predetermined pressure required for sheet feeding by the spring force externally applied to the calling arm 5 by a spring (not shown). are doing.

When the feed shaft 8 is rotated by a motor (not shown) from this paper feedable state, the drive gear 12 and the paper feed roller 3 rotate in the direction of the arrow D in FIG. 1, whereby the gear 13 idles. It rotates in the direction of arrow D via the gear 14, and the calling roller 2 also rotates in the same direction.

As a result, the uppermost sheet is fed in the direction of arrow B, and it is further fed by the sheet feeding roller 3 to a registration roller (not shown).

By the way, when two or more sheets are double-fed as shown in FIG. 4, the torque transmitted from the feed roller 3 to the reverse rotation roller 4 is the upper sheet P ₁ and the lower sheet P _2. Since the torque is transmitted via a small frictional force between them, the transmitted torque is below a predetermined torque at which the flanged cylindrical member 16 of the torque limiter 20 (Fig. 3) built into the reverse rotation roller 4 and the coil spring 18 are connected. Therefore, the reverse rotation roller 4 and the reverse rotation shaft 15 have a clutch ring 17, a coil spring 18, and a coil spring 18 in the torque limiter.
Connected via a cylindrical member 16 with a collar, and the reverse rotation roller 4 is indicated by arrow F.
The paper P ₂ on the lower side is returned to the cassette 1 again by rotating in the reverse direction.

At this time, after a lapse of a predetermined time in which the uppermost sheet is reliably fed between the paper feed roller 3 and the reverse rotation roller 4, an elevating device (not shown) lifts the right end side of the calling arm 5 around the feed shaft 8, Since the pressing roller 2 is released from the pressure contact with the paper, even if the lower paper P ₂ is returned by the reverse rotation roller 4, it is not hindered.

Then, after the lower sheet is returned by the double feeding, or when the next sheet is fed when there is no double feeding, the calling arm 5 is lowered and the calling roller 2 is pressed against the upper surface of the uppermost sheet again. Then, the same paper feeding as in the above case is repeated.

By the way, when slippery paper with a very small friction coefficient between the paper used and the peripheral speed of the reverse rotation roller is also very fast, the return position of the paper returned by double feeding is regulated. If there is no such member, the paper may be returned too far beyond the calling roller, and the next time the paper is re-fed, it may not be possible, resulting in poor conveyance.

However, since the feeding roller 2 is provided with the pressing roller 7 that presses the upper surface of the sheet even when the calling roller 2 is lifted and the pressure contact with the sheet is released, the friction coefficient that is likely to be excessively returned like this. Even when a small sheet of paper is returned, the pressing roller 7 lightly presses and presses the upper surface of the sheet, so that the paper does not return beyond the calling roller 2 too much.

Therefore, since this paper feeding device can prevent the paper from being excessively returned during double feeding without providing a trailing edge presser or a trailing edge fence, conventionally, the size of the cassette in the paper feeding direction is It was necessary to set the maximum length of paper that can be stored in the cassette and the space for installing the trailing edge presser and trailing edge fence that prevent the paper from being excessively returned. Since it is not necessary, the cassette can be made smaller accordingly.

The pressing roller used as the paper pressing member in this embodiment may be applied to the paper by using a spring instead of only its own weight. The paper pressing member may be a contact piece or a contact plate.

Effects As described above, according to the present invention, it is possible to prevent the sheets from being excessively returned when the sheets are double-fed, without providing the trailing edge presser or the trailing edge fence in the sheet stacking portion. Thus, it is possible to provide a compact paper feeding device having excellent operability when exchanging paper.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an example in which the present invention is applied to a paper feeding device of a plain paper copying machine, FIG. 2 is a plan sectional view of the same, and FIG. 3 is built in the reversing roller 4 of FIG. FIG. 4 is a cross-sectional view showing a torque limiter being operated, FIG. 4 is an explanatory view for explaining a transmission torque transmitted from the paper feed roller 3 to the reverse rotation roller 4 when two or more sheets are double-fed, and FIG. It is a perspective view which simplifies and shows an example of the sheet feeding device provided with the trailing edge presser. 1 ... Cassette (paper stacking part) 2 ... Calling roller, 3 ... Paper feeding roller 4, Reversing roller, 5 ... Calling arm 6 ... Pressing arm 7 ... Pressing roller (paper pressing member) 15 ... Reverse rotation axis, 20 ... Torque limiter P … Paper

Claims (1)

(57) [Claims] 1. A calling roller that presses and rotates on an upper surface of a sheet in a sheet stacking section to feed the sheet, and a pair of sheet feeding rollers and a reversing roller having a torque limiter on the downstream side of the feeding roller. In the sheet feeding device, the upper surface of the sheet is pressed to a position upstream of the calling roller of the elevating member that presses or releases the calling roller to the upper surface of the sheet even when the calling roller releases the pressure contact of the sheet. A paper feeding device characterized in that a paper pressing member is attached.