JPH0818720B2 - Paper feeding device of image forming apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to a sheet feeding device provided in an image forming apparatus such as an electrostatographic copying machine or a printer.

[Conventional technology]

For example, a sheet feeding device of an electrostatic photocopier is input with a sheet feeding device for feeding untransferred sheets one by one to a transfer section every time a sheet feeding signal is input, and a sheet re-feeding signal. An intermediate paper feeding device for double-sided copying, which feeds the paper after single-sided copying to the transfer section each time, or a document feeding device that feeds a document sheet on the document table every time a sheet feeding signal is input. There is a device,
As a mode of feeding the paper, the conveying means and the double-feed preventing means, each of which has a frictional resistance larger than the frictional resistance of the sheets and contacting each other, are arranged on the downstream side of the paper feeding means in the paper feeding direction, and the feeding means is provided. When the paper is fed by the paper means between the carrying means and the double-feed preventing means in a state of two sheets being overlapped, only the paper on the carrying means side is fed based on the frictional resistance. is there.

Further, the double feed preventing means has a structure of a roller or a belt, and the double feed preventing means is configured to be rotatable by a predetermined angle only in a direction opposite to the sheet feeding direction. By changing the nip surface of the double feed preventing means with respect to the conveying means, uneven wear of the double feed preventing means is prevented, and the double feed preventing function can be favorably maintained for a long period of time.

[Problems to be solved by the invention]

By the way, there is a case where the above-mentioned double-feeding-prevented paper is unexpectedly sandwiched between the transport means and the double-feeding prevention means. Therefore, if the paper feed cassette is pulled out or the paper loading plate of the paper feed deck is lowered, the paper sandwiched between the both means remains in the paper feed unit, and the paper feed cassette or paper feed When a deck or the like is set and fed, a paper jam, that is, a so-called jam may occur.

Thus, while the double feed preventing means is provided so as to be freely contactable and separable,
Based on a signal from a sensor that detects the withdrawal of the paper feed cassette or the lowering of the paper loading plate of the paper feed deck, by separating the double feed preventing means from the conveying means by means such as a solenoid, When pulling out the paper feed cassette, paper feed deck, etc., it suffices to be able to take out the paper sandwiched between the both means. For that purpose, for detecting the pull out of the paper feed cassette, paper feed deck, etc. It requires means such as sensors and solenoids, and it dislikes cost increases.

The present invention has been made in view of the above-mentioned circumstances, and the occurrence of the jam is caused by a rational improvement that effectively utilizes a configuration for effectively preventing double feeding of sheets for a long period of time. The purpose is to be able to deter.

[Means for solving problems]

In order to achieve the above object, the present invention provides a sheet feeding device of an image forming apparatus, which comprises a conveying unit and a double feed preventing unit that is rotatable only in a direction opposite to a sheet feeding direction via a one-way clutch that is reciprocally rotated. In the above, the double feed preventing means is provided so as to be able to come in contact with and separate from the conveying means, and a solenoid is provided which is excited based on a signal output for paper replenishment. A rotating interlocking mechanism for rotating the double feed preventing means and the one-way clutch in the counter-feeding direction with respect to the spindle, and a contacting / separating mechanism for contacting / separating the double feed preventing means with the conveying means in the operating direction of the spindle. The feature is that it has an interlocking mechanism.

[Action]

According to the above characteristic structure, the spindle of the solenoid operated by the excitation of the solenoid is provided with the rotation interlocking mechanism for rotating the double feed preventing means and the one-way clutch in the anti-feeding direction, and the double feed preventing means. Since the interlocking mechanism for contacting / separating the moving means in the operating direction of the spindle is provided side by side, the nip surface of the double feed preventing means with respect to the conveying means is changed (surface change) to change the nip surface of the double feed preventing means. Uneven wear can be suppressed, and the prevention of double-feeding of sheets can be maintained satisfactorily for a long period of time, and at the same time, the operation of separating the conveying means from the double-feeding preventing means can be performed.

〔Example〕

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 2 shows an outline of a double-sided copying machine as an example of an image forming apparatus. A document holder 2 having an automatic document feeder 1 is provided on the top of the copying machine body 3 and a photoconductor is provided on the copying machine body 3. 4, a charging device 5, a developing device 6, a transfer device 7, a sheet separating device 8 and a cleaning device 9 are arranged around the photoconductor 4 in the stated order in the rotation direction of the photoconductor 4. An optical system movable exposure device 10 is arranged in the upper space of the copying machine main body 3, and a paper feeding / conveying device 13 that conveys the paper in the manual feeding portion 11 or the paper feeding cassette 12 to the transfer device 7, and a transfer device. A sheet discharging and conveying device 15 that conveys the separated sheet to the fixing device 14 and a sheet discharging roller pair 17 that discharges the sheet after fixing to the tray 16.

An intermediate paper feeding device 18 having a double feed prevention function is provided in the lower space of the copying machine body 3, and a switchback mechanism 19 for selectively ejecting the fixed paper to the intermediate paper feeding device 18. A conveying device 20 is disposed between the fixing device 14 and the paper discharge roller pair 17, and further conveys the single-sided copied sheets stored in the intermediate paper feeding device 18 to the paper feeding and conveying device 13. On the other hand, an elevator type paper feed deck 21 capable of accommodating a large amount of paper is provided below the arrangement part of the paper feed cassette 12, and the elevator type paper feed deck 21 is provided.
A sheet feeding device 22 having a double feed preventing function is provided to cause the sheets from the above to be fed together to the conveying device 20.

Thus, a single-sided copy mode in which an image is copied on one side of a sheet fed from the manual feed section 11, the cassette case 12, or the sheet feed deck 21, and the sheet after the one-sided copy is discharged to the tray 16 is used. A double-sided copy mode in which an image is copied on the back side of a sheet after single-sided copying that is fed from the intermediate sheet feeding device 18 at a predetermined timing, and the sheet after double-sided copying is discharged to the tray 16. Is configured to be selectable.

Next, a specific configuration of the paper feeding device 22 for the paper feeding deck 21 will be described. This paper feeding guide is provided in the paper feeding section of the paper feeding deck 21 as shown in FIGS.
23 are connected to each other and are opened on the slope plate of the paper feed guide 23.
A rubber conveying roller (an example of a conveying means) 25 made of rubber is provided on the upper side of the paper feed guide 23 so as to correspond to the opening 24. Feeding prevention rollers (an example of double feeding prevention means) 26, 26 are provided with a part of the peripheral surface thereof protruding upward from the opening 24, and the double feeding prevention rollers 26, 26 are provided at predetermined angles. A drive means 27 for rotating in the anti-feeding direction and a drive system of the drive means 27 are used to move the double feed prevention rollers 26, 26 to the conveying roller 2.
An interlocking mechanism 28 for moving toward and away from 5 is provided.

Specifically, a pair of brackets 29, 29 each having a long hole a extending in the direction connecting the rotation axis of the rollers 25, 26 are arranged on the lower surface side of the paper feed guide 23, and the brackets 29, 29 are also arranged. The rotation support shaft 31 of the double feed prevention roller 26 is installed over a pair of bearings 30, 30 slidable along the long hole a of 29, and the bearings 30, 30 are directed upward. Biasing devices (for example, coil springs) 32, 32 for urging are connected to the brackets 29, 29 so that the double feed preventing rollers 26, 26 can be brought into and out of contact with the conveying roller 25.

It should be noted that the frictional resistance of the transport roller 25 is a double feed prevention roller.
The frictional resistance of the double feed prevention rollers 26, 26 is set to be larger than the frictional resistance of the papers 26, 26 and the frictional resistance of the papers 26, 26 is set larger than the frictional resistance of the papers. When fed between the transport roller 25 and the double feed prevention rollers 26, 26 in a two-ply state, the paper on the transport roller 25 side can be fed based on the friction resistance. .

On the other hand, the drive means 27 for rotating the double feed preventing rollers 26, 26 only in the non-feed direction is constructed as follows. That is, the inner rotating body of the one-way clutch 34 is fixed to the support shaft 31 between the two double feed preventing rollers 26, 26, and the outer rotating body of the one-way clutch 34 is armed.
35 are connected, a solenoid 37 is attached to a bracket 36 below the paper feed guide 23, and the solenoid 37
The spindle b of 37 and the free end side of the arm 35 are connected to the shafts 38, 3
It is pivotally connected by a first link 40 via 9. still,
The one-way clutch 34 includes an inner rotating body (and by extension, a double-feeding prevention roller continuously provided on the inner rotating body).
The rotation permissible direction is set so that the (26, 26) can freely rotate only in the counter paper feeding direction (clockwise direction in FIG. 1) with respect to the outer rotating body.

Thus, for example, when the solenoid 37 is excited based on the input of the signal for lowering the sheet loading plate 21a of the sheet feeding deck 21 and the spindle b is retracted into the solenoid case c, it is interlocked with this. The first link 40 is attracted, and the arm 35 is pulled by the movement of the first link 40, whereby the double feed prevention roller 26, which is connected to the entire one-way clutch 34 and the inner rotating body thereof, 2
6 and 6 rotate integrally in the direction opposite to the sheet feeding direction, and by extension, the nip surface of the double feed preventing rollers 26, 26 with respect to the conveying roller 25 is changed to thereby prevent the double feed rollers 26, Uneven wear of the nip surface of 26 is suppressed, and long-term double feed prevention is achieved.

Next, the double feed prevention roller 2 for the conveyance roller 25
Explaining the interlocking mechanism 28 for contact and separation movement of 6,26, this one provides a link mounting member 42 on the support member 41 of the brackets 29, 29 and pivots a second link 43 on the link mounting member 42. The second link 43 is connected by a support and a long hole is formed on the other end side of the second link 43 so that the long hole is linked to the connecting link shaft 38 of the spindle b and the first link 40.
A connecting shaft 44 is fixed to an intermediate portion of the link 43, and the third link 4 is provided across both ends of the connecting shaft 44 and both ends of the rotary support shaft 31.
It consists of 5,45 pivotally connected.

Thus, as described above, when the solenoid 37 is excited and the spindle b is retracted into the solenoid case c, it is interlocked with the rotation of the double feed preventing rollers 26, 26 in the direction opposite to the sheet feeding direction. Then, the second link 43 swings toward the solenoid case c, and the third links 45, 45 interlock with the swing of the second link 43 to move downward against the biasing tools 32, 32. When the double feed prevention rollers 26, 26 are separated from the transport roller 25 by being pulled, and the solenoid 37 is demagnetized, the double feed is performed based on the biasing force of the biasing tools 32, 32. The prevention rollers 26, 26 are configured to come into contact with the transport roller 25.

That is, based on the input of the signal for lowering the paper loading plate 21a of the paper feed deck 21, the double feed prevention rollers 26, 26 are reversed from the state shown in FIG. 4 to the state shown in FIG. The double feed prevention rollers 26, 26 are separated from the transport roller 25 at the same time as the double feed prevention rollers 26, 26 are rotated in the paper feeding direction. Therefore, between the transport roller 25 and the double feed prevention rollers 26, 26. Even if the paper is sandwiched between the rollers, the paper can be taken out from between the rollers 25 and 26 as the paper loading plate 21a descends.

Incidentally, although the roller structure has been shown as the means for preventing the double feeding of the sheets, a belt structure can be used instead of this, and in the embodiment, the sheet feeding device 22 for the sheet feeding deck 21
Although the explanation was given for the manual,
The paper feeding device of the present invention or the intermediate paper feeding device 18 for re-feeding for double-sided copying may be applied, or the paper feeding device for various image forming apparatuses such as a printer or a facsimile is not limited to a copying machine. Can be implemented.

〔The invention's effect〕

As described above, the present invention provides a rotation interlocking mechanism for rotating the double feed preventing means and the one-way clutch in the anti-feeding direction on the spindle of the solenoid operated by the excitation of the solenoid, and the double feed preventing means. Since the interlocking mechanism for contacting / separating the moving means in the operating direction of the spindle is provided side by side, the nip surface of the double feed preventing means with respect to the conveying means is changed (surface change), and the nip surface of the double feed preventing means is changed. The uneven wear can be suppressed, and the prevention of the double feeding of the sheets can be favorably maintained for a long period of time, and at the same time, the separating operation of the conveying means from the double feeding preventing means can be performed.

That is, according to the present invention, it is possible to remove the surface change and double feed prevention means from the conveying means only by providing the spindle of the solenoid with the rotation interlocking mechanism and the contacting / separating interlocking mechanism together without adding a special drive mechanism. The separating operation can be performed automatically at the same time, and the separating operation makes it possible to easily take out the sheet sandwiched between the conveying unit and the double-feed preventing unit. It is possible to prevent the occurrence of a jam due to the cost at a low cost.

[Brief description of drawings]

FIG. 1 is a detailed view of a sheet feeding device for a sheet feeding deck, FIG. 2 is a schematic vertical sectional side view of a double-sided copying machine as an example of an image forming apparatus,
FIG. 3 is a plan view of the paper feeding device shown in FIG. 1, and FIGS. 4 and 5 are explanatory views of the rotation of the double feed preventing roller and the contact and separation with respect to the conveying roller. 25 ... conveying means (conveying roller), 26 ... double feeding preventing means (double feeding preventing roller), 28 ... interlocking mechanism, 34 ... one way clutch, 37 ... solenoid, b ... spindle.

Claims (1)

[Claims] 1. A sheet feeding device of an image forming apparatus, comprising: a sheet feeding device and a sheet feeding preventing device that is rotatable only in a direction opposite to a sheet feeding direction via a one-way clutch that is reciprocally rotated. And a solenoid that is excited based on a signal output for paper replenishment. Further, the solenoid spindle that is activated by the excitation of the solenoid prevents the double feed. A rotation interlocking mechanism for rotating the device and the one-way clutch in the anti-feeding direction, and a contacting / separating interlocking mechanism for contacting / separating the double feed preventing unit with the conveying unit in the spindle operating direction are provided. A sheet feeding device of an image forming apparatus, characterized in that