JPH02144334A - Sheet supply device - Google Patents

Abstract

PURPOSE:To prevent generation of jam by supplying forward a sheet by a double-sheet feed preventing roller, reversing the roller, and temporarily reversing a delivery roller, a feed roller in response to the reversing double-sheet feed preventing roller to return next sheets. CONSTITUTION:After the rear end of a conveyed sheet P1 passes through a nip part of a double-sheet feed preventing roller 21, the double-sheet feed preventing roller 21 is directly pressed against the peripheral surface of a feed roller 12. Since the double-sheet feed preventing roller reverses, the feed roller 12 is also driven to reverse, and reverses to the extent of backlashes of a recessed part 122A of a collar member and a projected part 17A of a one way clutch, and then stops. A delivery roller 11 also reverses through an intermediate roller 13 to the extent of its backlash by reversing of the feed roller 12, and the second and following sheets P2 are returned from the nip part. Jam of the following sheets after supplying a sheet is thus prevented.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a paper feeding device for sheet paper in devices such as copying machines, facsimile machines, printers, etc., and a document feeding device for sheet document documents. The present invention relates to a double-feed prevention device that prevents multiple sheets from being fed at once.

[Conventional technology]

Conventionally, in devices such as copying machines, facsimile machines, and printers, sheets of paper stacked in paper trays, paper feed centers, paper stunkers, etc. are taken out one by one from the top or bottom, and the image recording section A paper feeding device is provided to feed the paper to other places.

In addition, in a document feeding device such as a copying machine or an image reading device, the sheet document stacked on the paper feed tray is taken out one sheet at a time from the top or the bottom and sent to the exposure section on the document platen glass. A paper machine is provided.

The paper feeding device disclosed in Japanese Patent Application Laid-Open No. 63-33865 is of a corner separator type using separation claws.

Although this device has a simple structure, it is easily affected by the thickness of the paper, how stiff it is, temperature and humidity, and has problems with reliability.

As a paper feeding device that solves the above problems and improves the operability of loading paper into a paper feeding cassette, a device called a friction separation roller system is generally put into practical use.

This type of sheet feeding device is disclosed in Japanese Patent Application Laid-Open No. 62105.
As shown in Japanese Patent Laid-open No. 834 and Japanese Patent Application Laid-open No. 63-57447, a feed roller and a separating roller are provided in front of the feeding roller so as to be in contact with each other, and the fed sheet material is separated between the feeding roller and the separating roller. By inserting the paper between them, the paper is separated and fed one by one.

Such a paper feeding device will be explained according to an example shown in FIG. In a normal paper feeding device, as shown in the figure, the sheets P stacked and placed on the bottom plate 2 in the paper feeding force cellar l-1 are moved by the action of the bottom plate push-up lever 3 to the feed roller (first 1
The feed roller 2 is provided so as to be in pressure contact with the feed roller 4, and the paper P is sent out by the rotation of the feed roller 2.

Further, following the feed roller 4, a paper handling mechanism is provided in which a separation belt 5 and a double feed prevention roller 6 are provided facing each other.
When paper P is multi-fed (feeding multiple sheets), there is a mechanism that feeds out only the topmost sheet of the multi-fed sheets, thereby stopping or returning the paper P below. It is provided.

In the paper handling mechanism described above, the separation belt (or feed roller) 5 is driven and rotated integrally with the drive roller 7 via a gear train from a drive source (not shown). The double-feed prevention roller 6 is spring-biased and configured to press the separation belt 5.

In the paper feeding process of this paper feeding device, first, the upper surface position of the paper P rises to a set position, and the feed roller 4 and separation belt 5 start rotating in response to a paper feeding signal. The feed roller 4, which is pressed against the upper surface of the paper with a predetermined pressure, is released from the paper surface after feeding the paper P to the nip position between the separation belt 5 and the double-feed prevention roller 6.

The double-feed prevention roller 6 is driven in the opposite direction to the traveling direction of the paper P, and is pressed against the separation belt 5 by the spring biasing force.

When the double-feed prevention roller 6 comes into direct contact with the separation belt 5 and there is no paper between the tabs), or when one sheet of paper P is fed between the nip, it slips beyond the limit torque and the separation belt 5 Rotates driven by. However, when two or more sheets of paper P are fed into the nip, the limit torque overcomes the frictional force between the sheets, causing the double-feed prevention roller 6 to rotate in the opposite direction, pushing back the lower sheet of paper (multi-feeding). sending)
is prevented. In FIG. 8, solid line arrows marked on each rotating body indicate the direction of rotation when sheets are not being fed in duplicate, and broken line arrows indicate the direction of rotation when sheets are being fed in duplicate.

As described above, the sheets P separated and fed one by one are conveyed to the registration rollers (second paper feeding rollers) 8.

[Problem that the invention seeks to solve]

However, in the conventional paper handling mechanism as described above, the separation belt 5 and the double feed prevention roller 6
After the feeding of the second sheet of paper P is finished, the leading edge of the second sheet of paper P is returned to the pressure contact position of both rollers, immediately adjacent to the nub position) on the circumferential surface of the double-feed prevention roller 6. It is stagnant and waiting in contact with the top.

If the paper feed cassette 1 is pulled out in this state, the topmost sheet of paper P will remain in the paper feed device.

If the paper feed cassette is attached/detached without noticing the remaining paper, paper feeding may become defective and components such as sensors and rollers may be damaged.

Also, when the topmost sheet of paper P in the paper feed cassette l is near the double-feed prevention roller 6, manual misfeed 1. When paper is fed by the paper feeder 9, the manually fed paper overlaps the previous paper P, causing a paper feed failure.

[Means for solving problems]

The present invention eliminates the drawbacks of conventional paper feeding devices as described above, and provides a paper feeding device that prevents damage to the device due to residual paper, eliminates the need for operational precautions, and realizes normal paper feeding. It is intended to.

The paper feeding device of the present invention that achieves the above object rotates in the feeding direction of the sheet in front of a feed roller that presses against a plurality of stacked sheets and feeds out the sheet. A paper feeding device is equipped with an electrical transmission prevention means consisting of a feed roller and a double-feed prevention roller that is in pressure contact with the feed roller. is provided, and after the double-feed prevention means finishes feeding out one sheet-like object, the double-feed prevention roller temporarily reverses rotation in response to the reversal of the double-feed prevention roller mentioned in OiI, and the subsequent two sheets are temporarily reversed. This paper is characterized in that it is configured to return the paper after the first one.

〔Example〕

Embodiments of the paper feeding device of the present invention will be described below with reference to the drawings.

As shown in FIG. 7, the paper feeding device according to the present invention includes a paper feeding cassette B, a first paper feeding section Bl, a second phase paper section B2, and a paper feeding cassette B removably provided on the side surface of an image forming apparatus A. , a paper feed section CI of a multi-sheet paper feed unit RC that can store a large amount of paper (for example, about 1000 sheets) provided below, and an image forming apparatus A.
The paper feed section DI of the automatic double-sided copying device installed at the bottom of the
It is also used in the paper feed section El of the automatic document feeder E provided above the image forming apparatus.

FIG. 1 shows an example of the paper feed sections B 1 and B 2 according to the present invention, and in the figure, parts having the same functions as those in FIG. 8 are designated by the same reference numerals.

Paper (transfer material) P stacked and placed on the bottom plate 2 in the paper feed cassette 1 is pressed against the feed roller 11 by the action of the bottom plate push-up lever 3 . The feed roller 11 is rotated by the transfer material feed signal, and the paper P is separated by the feed roller 11 and the feed roller 12, which constitute the double feed prevention means, and the double feed prevention roller 21, which is fixed.
The sheets are fed and transported one by one to the next process. At this time, if only one sheet of paper P is sent out by the feeding roller 11,
Paper is fed and conveyed by being pulled by the friction surface of the roller 12 and sliding on the surface of the double-feed prevention roller 21. Also, if the transfer material P is double-feeded, the lower paper P is pulled by the double-feed prevention roller 21. It is stopped by the friction of the surface of the roller 21, and only the upper paper P is pulled by the friction surface of the feed roller 12, and is fed and conveyed while sliding on the surface of the lower paper P.

The paper P fed one by one as described above is conveyed to the registration rollers 30, but before that, the leading edge is detected by the sensor 33, and the drive source of the feed roller 11 is activated by the detection signal 1. will be stopped.

At this time, the paper P is transferred to the registration roller 30 of the second paper feed section B2.
However, there is a slight delay in stopping the drive source (approximately 0.2 seconds).
A loop is formed from 2 to 0.7 seconds), and the restoring force of the loop causes the leading edge of the paper P to sink into the nip, and the leading edge of the paper P is aligned and the skew is corrected.

The double-feed prevention means includes a feed roller 11, a double-feed prevention roller 2L, an idler gear G1 that is interlocked with the double-feed prevention roller 21 through a gear, and a torque limiter 22 that is also interlocked with the idler gear Gl through a gear. ,
The rotation axis of the idler gear Gl is the torque limiter 2 marked in 11.
It is supported by a support member 24 rotatably mounted on the drive shaft 23 of No. 2.

Here, the lower end of the support member 24 is connected to the other end of a coil spring 25 whose one end is fixed to the main body, so the support member 24 rotates counterclockwise around the drive shaft 23 of the torque limiter 22. is urged to do so.

Therefore, the double feed prevention roller 21 supported by the support member 24 is pressed against the feed roller 12.

Further, as shown in FIG. 2, the torque limiter 22 includes a magnetic internal roller 26 that is integrated with the drive shaft 23, and a magnetic internal roller 26 that is externally mounted on the internal roller 26 and that is connected to the idler gear G1.
The external roller 27 is also magnetic and is interlocked with a gear, and magnetic powder 28 is inserted between the two to magnetically transmit the rotational force of the drive shaft 23 to the external roller 27. Note that the drive @23 is rotated in a direction that reverses the double feeding prevention roller 21 (a direction that returns the transfer material P).

FIG. 3 is a cross-sectional view taken almost horizontally of the main parts of the drive and feeding system above the first paper feed section Bl, FIG. 4 is a front view thereof, and FIG. 5 is an exploded perspective view of the feed roller drive shaft. .

In these figures, the delivery roller 11. Feed roller 12. Relay roller 13. The manual feed roller 20 is supported by the frame 14 and driven by gear transmission.

The feed roller 12 is connected to a gear G from a drive source (not shown).
2 and G3, and is driven and rotated integrally with the drive shaft 15. The drive shaft 15 has a bearing member 16 fixed to the frame 14.
It is rotatably supported by A and 16B.

At one end of the drive shaft 15, a feed roller 12 having an elastic ring 121 pressure-wound around the circumferential surface of a collar member 122 is rotatably fitted, and near the tip of the drive shaft 15,
A one-way clutch 17 is attached to be rotatable in one direction.

A semicircular recess 122A is cut in the outer end face of the collar member 122, and the protrusion 17A of the one-way clutch 17 fits into the recess 122A. The projection circumferential angle of the convex portion 17A is smaller than the hole circumferential angle of the recessed portion 122A, and has an play angle (margin angle) of 5″ to 15°, allowing relative rotation by this play angle. That is, ゛,
When the one-way clutch 17 is fixed, the feed roller 12 can rotate by the above-mentioned play angle.

A gear G4 is fixedly installed in the middle of the drive shaft 15, meshing with an idler gear G5, and further meshing with a gear G5 fixedly installed on a rotating shaft 18 having a feed roller 11, thereby performing gear transmission drive. .

The rotating shaft 18 has a bearing member 16 fixed to the frame 14.
c, rotatably supported by 16D. At one end of the rotating shaft 18, a delivery roller 11 having an elastic ring Ill wrapped around the circumferential surface of a collar member 112 is rotatably fitted. A one-way clutch 19 is attached so as to be rotatable in one direction.

The collar member 112 and the one-way clutch 19 are formed with a concave portion 112A and a convex portion 19A having the same shape as the feed roller 12, and similarly allow slight rotation due to the play angle thereof.

Note that the manual feed roller 20 supported by the frame 14 on the upstream side of paper feed feeds the paper to the first paper feed section during manual paper feed, and has an idler gear G7 meshing with the gear G6 of the gear train. A gear G8 is rotationally driven through the manual feeding roller 2o, and is rotated in one direction by a one-way clutch built in the manual feeding roller 2o.

A relay roller 13 is provided between the feed roller 11 and the feed roller 12 and is rotatable in pressure contact with both the rollers 11 and 12. The relay roller 13 is connected to the frame body 1
4 and the stand shaft 132 implanted in the stand shaft 13
2 and a rotatably supported roller 131.

Next, the sixth section will explain the paper feeding operation of the paper feeding device according to the present invention.
This will be explained based on figures (A), (B), and (C).

FIG. 6(A) is a diagram showing a state in which one sheet of paper P is fed. In the paper feeding process, first, the top surface of the paper P is raised to a set position by the rocking of the bottom plate push-up lever 3, and the feed roller 12 and the delivery roller 11 start rotating forward in response to a paper feeding signal.

This forward rotating feed roller 11 and the paper feed cassette l
At least one sheet of paper P, which is pressed and held between the push-up blade of the bottom plate push-up lever 3 of
and the double feed prevention roller 21.

The double feed prevention roller 21 is driven in the opposite direction to the paper traveling direction via a torque limiter 23, and is pressed against the feed roller 12 by the initial pressure from the coil spring 25 and the operating pressure generated by the torque of the torque limiter 22. There is.

The double feed prevention roller 21 is the feed roller 12. ! = Straight f
When there is no paper P between the flanges when they make contact) or when one sheet of paper P is fed between the nip, it slips beyond the limit torque and rotates as a result of the feed roller 12. However, when two or more sheets of paper P are fed between the nips, the limit torque overcomes the frictional force between the sheets,
The double-feed prevention roller is rotated in the opposite direction to push back the lower paper P to prevent multiple sheets from being fed.

In the above paper feeding process, the feed roller 12 is driven and rotated together with the drive shaft 15, and at the same time, the feed roller 11 is also driven and rotated by power transmission through the gear trains G4 to G8. That is, the right end surface of the convex portion 17A of the one-way clutch 17 that rotates together with the drive shaft 15 is connected to the collar member 12 of the feed roller 12 that is loosely fitted to the drive shaft 15.
The feed roller 1 is in contact with the right end of the concave portion 122A of
2 is integrated with a one-way clutch 17 and driven and rotated. Further, the feed roller 11 is also connected to the rotating shaft 1 in the same manner.
One-way clutch 1 that is driven and rotated together with 8
The convex portion 19A of No. 9 comes into contact with the concave portion 112A of the collar member 112 of the delivery roller 11 that is loosely fitted to the rotating shaft 18,
The feed roller 11 is driven and rotated integrally with a one-way clutch 19.

FIG. 6(B) is a diagram showing a state in which the paper that has passed the nip position of the first paper feed section Bl is nipped and fed by the second paper feed section B2.

Only one sheet of paper P has been fed by the feed roller 12 and the double-feed prevention roller 21 of the first paper feed section B1, and is brought to a stopped state by the drive roller 31 and driven roller 32 of the second paper feed section B2. Before being fed to a certain registration roller unit 30, the leading edge of the paper P is detected by the sensor 33, and the drive source of the first paper feeding unit Bl is stopped based on the detection signal. At this time, the paper P is brought into contact with the nip section of the registration roller section 30, but a loop is formed due to the time lag after the drive source stops, and the restoring force of the loop causes the leading edge of the paper P to sink into the nip section, and The leading edge of the paper is aligned and the skew is corrected.

The paper P, which is thus placed on the registration roller section 30 and whose leading edge is aligned, is conveyed while being held under pressure by the registration rollers 3°. When the paper is conveyed by the registration rollers 30, as described above, the drive of the first paper feed section B1 is stopped and the drive shaft 15° rotation shaft 18 is stopped, but due to the conveyance force of the paper P by the registration rollers 3o, The feed roller 12 and the delivery roller 11 rotate idly while being in pressure contact with the double-feed prevention roller 21.

Due to this idle rotation of the feed roller 12, the end face of the concave portion 121A of the collar member 121 constituting the feed roller 12 comes into contact with the end face of the concave portion 17A of the one-way clutch 17, causing the one-way clutch 17 to idle in the same direction as shown in the figure. . In addition, due to the idle rotation of the feed roller 11,
Similarly, the one-way clutch 19 is also idled in the same direction. During this time, when there is one sheet of paper in the nip, the double-feed prevention roller 21 rotates in order, and when two sheets of paper are in the nip.
When more than one sheet of paper is inserted, the machine reverses direction and returns the second and subsequent sheets.

FIG. 6(C) shows that the trailing edge of the paper P that was previously conveyed is
7 is a diagram illustrating a state in which the paper has passed through the nip portion of the paper feed section Bl. FIG. In the figure, feed roller 12 and double feed prevention roller 2
When the paper P1 finishes passing through the nip portion of No. 1, the circumferential surface of the double-feed prevention roller 21 comes into direct pressure contact with the circumferential surface of the feed roller 12, and at this time, the double-feed prevention roller 21 is reversely rotated in the direction of the arrow. , the feeder 12 follows this and reverses. As a result, the recess 122A of the collar member 122 of the feed roller 12 is reversed counterclockwise, and the recess 122A of the collar member 122 of the feed roller 12 is rotated counterclockwise.
It rotates by the amount of play between the clutch 22A and the convex portion 17A, and comes into contact with the convex portion 17A of the one-way clutch 17, which is stopped and cannot be reversed, and stops.

As the feed roller 12 is reversed in the counterclockwise direction, the relay roller 13 circumscribing the elastic ring 121 on its outer periphery is driven to rotate, and the feed roller 11 that is in contact with this is also driven to reverse in the counterclockwise direction, as described above. Part 4 112A
rotates slightly by the amount of play and stops after coming into contact with the convex portion 19A.

The preceding paper P is moved by the operation of each roller described above.

Immediately after passing the paper P2, the subsequent paper P2 fed into the nip or the paper P2 near the nip, the feed roller 11 and the feed roller 12. Double feed prevention roller 2
1, and the feed roller 11 and the feed roller 12 rotate slightly by the amount of play described above and then stop, so that the paper P2 stops at the position where it was pulled back from the nip portion.

Thereafter, a signal from a sensor that detects the optical scanning start position of the original to be copied causes the registration roller section 3 to move again.
0 is driven, the paper P1 is conveyed to the transfer area in accordance with the image forming timing, and the toner image formed on the image forming body by the image forming means is transferred. Subsequently, the subsequent sheet P2 is also conveyed in the same manner.

The paper feeding device of the present invention is not only effective when applied to the various paper feeding units shown in FIG. 7, but also applicable to multifeed separation means in general friction separation roller type paper feeding devices in facsimiles, printers, etc. It is.

〔Effect of the invention〕

As explained above, since the paper feeding device of the present invention has the above-described configuration, the drive shaft that drives and rotates the feed roller and the delivery roller is driven in only one direction, and both rollers can be rotated in reverse. This is effective in eliminating paper feeding failures and damage to various parts of the paper feeding device due to subsequent paper jams after paper feeding.

Particularly, in a paper feeding device that is also capable of manual paper feeding, the paper on the paper cassette and the manually fed paper do not overlap and cause a paper feeding failure, and paper feeding is performed reliably and smoothly.

In addition, since the following paper is returned after double feeding is prevented using the power of the l-lucriminter to prevent double feeding, a specific drive source is not required, the structure is simple, the paper feeding device is compact, and parts are not required. It has an excellent effect on cost reduction.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the paper feeding device according to the present invention, FIG. 2 is a sectional view of the double feeding prevention means, FIG. 3 is a sectional view of the first paper feeding section, FIG. 4 is a front view thereof, and FIG. The figure is an exploded perspective view of the feed roller drive shaft, FIG. 6 is a diagram explaining the paper feeding operation of the paper feeding device,
FIG. 7 is a configuration diagram showing the paper feeding section of each part of the copying machine according to the present invention, and FIG. 8 is a sectional view of a conventional paper feeding device. 11... Delivery roller 12... Feed roller 13... Relay roller 15... Drive shaft 17
．． 19... One-way clutch 17A, 19A... Convex portion 18... Rotating shaft 20... Manual feed roller 21... Double feed prevention roller 22... Torque limiter 30... Registration roller portion 31. ... Drive roller 32 ... Followed roller 1
12.122...Carrying member 112A, 122A
...Concave portion Bl...First paper feed section B2...Second paper feed section P...Paper (transfer paper, sheet-like material)

Claims (1)

[Claims] A feed roller that rotates in the feeding direction of the sent out sheet is placed in front of a feed roller that presses against a stack of sheets and sends out the sheet, and a double feed prevention roller that presses against this feed roller. In a sheet feeding device equipped with a double-feed prevention means consisting of a roller, the feed roller and the feed roller are provided with a one-way clutch and a forward/reverse rotation regulating member, and the double-feed prevention means finishes feeding one sheet-like object. Then, in response to the reverse rotation of the double-feed prevention roller, the feed roller and the feed roller are temporarily reversed to return the second and subsequent sheets of paper.