JPH07237785A - Paper feeding device and image forming device - Google Patents

Abstract

PURPOSE:To return a sheet member left at a pair of separating rollers part (a pair of retard rollers) into a sheet member accommodation device, when the image formation operation is suspended by the input of a jam detection signal. CONSTITUTION:In the vicinity of a pair of retard rollers 25, a sheet member releasing means 60 which separates a retard roller 32 from a feed roller 31, when a jam detection signal is inputted, and enables the revolution of the retard roller 32 in the reverse direction to the transfer direction of the feed roller 31, and returns a sheet member S positioned between the retard roller 32 and the feed roller 31 into a paper feeding deck 20 is arranged. The sheet member releasing means 60 consists of a swing arm 52 having a driven roller 51 installed on one end side and an actuator 54 connected with the swing arm 52.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeding device used in an image forming apparatus such as a copying machine, a printer or a facsimile, and more specifically, it separates sheet materials fed from a sheet feeding section one by one. The present invention relates to a sheet feeding device including a separating unit that conveys a sheet to a downstream side and an image forming apparatus including the sheet feeding device.

[0002]

2. Description of the Related Art As a sheet feeding device provided in an image forming apparatus such as a copying machine, a printer, a facsimile, etc., generally, a retarding roller composed of a feed roller and a retard roller is used because of high separation performance of the fed sheet material. A so-called retard separation type sheet feeding device using a pair of rollers (separation means) is often employed.

FIG. 8 shows such a retard separation type sheet feeder.

The paper feeding device 6 is a pickup roller (paper feeding section) for feeding the uppermost sheet of the sheet material S loaded on the lifter plate 22 of the paper feeding deck (sheet material storing device) 2 by rotating it in the arrow direction. ) 23, a retard roller pair 25 that separates the sheet material S fed by the pickup roller 23 one by one in the case of a plurality of sheets, and conveys it downstream, and a retard roller on the downstream side of the retard roller pair 25. A sheet material detection unit 26 that detects the sheet material S that has passed through the pair 25 is provided.

The sheet material detecting means 26 is a sheet material S.
In addition to checking the paper feeding status of the
It also has a function of detecting a jam of the sheet material S (so-called defective conveyance such as a paper jam) and a residual state in the five parts. The retard roller pair 25 is composed of a feed roller 31 and a retard roller 32, and as shown in FIG. 9, both are linked by a timing belt 37 so as to rotate synchronously. The torque limiter 40 is interposed in the retard roller 32.
When a torque greater than a predetermined value acts on the relay shaft 39, the power transmission from the relay shaft 39 to the roller shaft 42 side is cut off, and the retard roller 32
Are driven by the feed roller 31.

Sheet material detecting means for detecting jams are installed at various places in the sheet material conveying path of the image forming apparatus. When a jam detection signal is input from any one of these sheet material detecting means, the image forming apparatus stops the copying operation.

When the image forming apparatus stops the copying operation by inputting a jam detection signal, the position of the sheet material remaining in the main body of the image forming apparatus is displayed on the display section on the operation panel or the indicator section on the electric board. Therefore, it is easy to remove the jam.

When the sheet material S fed from the paper feed deck 2 remains (or jams) on the retard roller pair 25 portion of the paper feed device 6 due to the stop of the copying operation, the state is shown in FIG. As shown, it is detected by the sheet material detecting means 26, and is displayed on the display unit or the like of the operation panel.

When a jam detection signal is input from any one of the sheet material detecting means in the main body of the image forming apparatus, the lifter plate 22 of the sheet feeding deck 2 moves the uppermost sheet position to a position lower than the pickup roller 23 by a distance L. It descends and forms a predetermined space in the part of the paper feed deck 2. This allows
The sheet material S remaining on the retard roller pair 25 can be easily removed by inserting a hand in the direction of the arrow from the side surface of the image forming apparatus main body.

In this way, the sheet material S remaining on the retard roller pair 25 is processed. When the jammed sheet material S is processed, the lifter plate 22 is raised by the jam recovery signal and the top sheet is picked up. The paper is returned to the state of being in contact with the roller 23 at a predetermined pressure (Japanese Patent Application Laid-Open No. Hei 5).
-132192).

[0011]

However, the paper feed deck 2
The sheet material S fed from the sheet and remaining (or jammed) in the retard roller pair 25 portion of the sheet feeding device 6 is not always detected by the sheet material detecting means 26 as shown in FIG. As shown in FIG.
There are many cases where the detection is not performed by (the detection lever 29 is not pushed up).

As described above, when the sheet material S remaining on the retard roller pair 25 is not detected by the sheet material detecting means 26, the residual position of the sheet material S is not displayed on the display portion of the operation panel. Therefore, when a jam occurs in a part other than the retard roller pair 25, when the jam is removed, the lifter plate 22 is lifted while the sheet material S remaining in the retard roller pair 25 remains. After the restoration (see FIG. 8), the copying operation is restarted.

Therefore, as shown in FIG. 12, the rear end portion of the sheet material S remaining on the pair of retard rollers 25 is pushed up by the sheet material S on the lifter plate 22 and is folded. There is a risk that it may become jammed in the retard roller pair 25 portion.

Further, in the case of the sheet loading cassette in which the cassette loading / unloading method is the front loading performed in the front and rear direction of the image forming apparatus and the sheet feeding apparatus having the same structure as the sheet feeding deck 2 is used. If there is a residual sheet material that is not detected by the sheet material detecting means as shown in FIG. 11, there is a possibility that the sheet material may be damaged between the image forming apparatus body and the cassette when the cassette is pulled out from the image forming apparatus. .

Therefore, according to the present invention, when the image forming operation is stopped by the input of the conveyance failure (jam) detection signal, the sheet material remaining in the separating means (the retard roller pair) can be returned to the sheet material storage device. An object of the present invention is to provide a sheet feeding device that can be used and an image forming apparatus that includes the sheet feeding device.

[0016]

According to the present invention, a pickup means (23) for feeding a sheet material (S) from a sheet material storage device (2) in which a plurality of sheet materials (S) are stacked and stored. And a normal rotating body (31) that rotates in the sheet material conveying direction and a separating rotating body (32) that can reversely rotate with respect to the normal rotating body (31), and are supplied from the pickup means (23). Separation means (2) that conveys only one of the sent sheet materials (S) into the image forming apparatus main body (1) and returns the other sheet material (S) into the sheet material storage device (2).
5), and a normal rotation body (31) of the separating means, which is arranged in the vicinity of the separating means (25) and receives a conveyance failure detection signal. The sheet material release which returns the sheet material (S) in the separating means (25) to the inside of the sheet material storage device (2) by separating from the separating rotary body (32) and rotating the separating rotary body (32) in the reverse direction. Means (6
It is characterized by having 0).

Further, according to the present invention, a pickup roller (23) for feeding the sheet material (S) from the sheet material storage device (2) in which a plurality of sheet materials (S) are stacked and stored.
A feed roller (31) for feeding the sheet material (S) fed from the sheet material storage device (2) by the pickup roller (23) into the image forming apparatus main body (1); When the sheet material (S) fed from the sheet material accommodating device (2) is a plurality of sheets, the nip portion is arranged between the roller (31) and the feed roller (31). , The feed roller (3
When the sheet material (S) fed from the sheet material accommodating device (2) is one sheet while rotating in the direction opposite to the conveying direction of 1) to separate into one sheet material (S), And a retard roller (32) that rotates in the transport direction of the feed roller (31) to transport the sheet material (S), and the retard roller (3).
When the conveyance failure detection signal is input in the vicinity of 2), the retard roller (32) is moved to the feed roller (31).
The retard roller (32) and the feed roller (31) are separated from each other to allow the retard roller (32) to rotate in the direction opposite to the feeding direction of the feed roller (31).
The sheet material (S) located between the retard roller (32)
It is characterized in that it is provided with a sheet material releasing means (60) for returning the sheet material into the sheet material storage device (2) while being pressed.

The sheet material releasing means (60)
Is connected to the swing arm (52) to which the driven roller (51) is attached on one end side, and moves the swing arm (52) when a conveyance failure detection signal is input. The driven roller (51) is brought into pressure contact with the retard roller (32), and the retard roller (32) is fed to the feed roller (31).
And an actuator (54) which is separated from and allows the retard roller (32) to rotate in a direction opposite to the conveying direction of the feed roller (31).

Further, in the paper feeding device (6) of the present invention, the operation control means (79) for driving the actuator (54) and the retard roller (32) for a predetermined period of time after the conveyance failure detection signal is input. It is characterized by having.

Further, the sheet feeding device (6) of the present invention is provided with a sheet material detecting means (26) on the downstream side of the retard roller (32) in the sheet material conveying direction, and from the sheet material detecting means (26). The operation control means (79) actuates the actuator (54) and the retard roller (32) so that the amount of return of the sheet material by the retard roller (32) becomes larger than the distance to the retard roller (32). It is characterized by that.

Further, according to the present invention, a sheet material detecting means (26) is provided on the upstream side of the retard roller (32) in the sheet material conveying direction, and the sheet material detecting means (26) after the conveyance failure detection signal is inputted, the sheet material detecting means (26). Until the absence of (S) is detected, the actuator (5) is operated by the operation control means (79).
4) and the retard roller (32) are activated.

In addition, the image forming apparatus of the present invention comprises an image forming device (12, 12) for forming an image on the sheet feeding device (6) and the sheet material (S) fed by the sheet feeding device (6).
15) and are provided.

[0023]

When the conveyance failure detection signal is input, the sheet releasing means (60) causes the separating rotary body (32) to rotate normally (3).
The separation member (32) is rotated away from the rotating member (1) in the direction opposite to the normal rotation member, and the sheet material (S) in the separating means (25) is returned into the sheet material storage device (2).

Further, the sheet material release means (60) separates the retard roller (32) from the feed roller (31) when the conveyance failure detection signal is inputted, and the retard roller (32) is set in the sheet material conveyance direction. The rotation of the retard roller (32) and the feed roller (3) are made possible while rotating in the opposite direction and pressed against the retard roller (32).
1) The sheet material (S) sandwiched between them is returned into the sheet material storage device (2).

Further, the sheet releasing means (60) and the retard roller (32) are operated by the operation control means (79) for a predetermined time after the conveyance failure detection signal is inputted, so that the feed roller (31) and the retard roller (32) are actuated. Laura (3
The residual sheet material (S) sandwiched between 2) is reliably returned into the sheet material storage device (2).

In addition, a sheet material detecting means (26) is provided on the upstream side of the retard roller (32) in the sheet material conveying direction, and the sheet material detecting means (26) does not have any sheet material after the conveyance failure detection signal is inputted. Since the sheet release means (60) and the retard roller (32) are operated by the operation control means (79) until the detection is detected, the residual sheet material is returned to the sheet material storage device (2) more reliably.

The reference numerals in parentheses are for comparison with the drawings, and do not limit the structure of the present invention in any way.

[0028]

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

FIG. 1 is a side view of a sheet feeding device showing an embodiment of the present invention.

The sheet feeding device 6 is a pickup roller (pickup means) for feeding the uppermost sheet of the sheet material S stacked on the lifter plate 22 of the sheet feeding deck (sheet material storage device) 2 by rotating it in the direction of the arrow. 23 and a pair of retard rollers 25 that separates the sheet material S fed by the pickup roller 23 one by one in the case of a plurality of sheets and conveys it downstream.
(Separating means) and a sheet material detecting means 26 for detecting the sheet material S that has passed through the retard roller pair 25 on the downstream side of the retard roller pair 25.

The sheet material detecting means 26 has a function of not only confirming the sheet feeding state of the sheet material S but also a function of detecting a conveyance failure (jam) and a residual state of the sheet material S in the retard roller pair 25 portion. ing.

Sheet material detecting means 100 for detecting a jam is installed at various places in the sheet material conveying path of the image forming apparatus. When a jam detection signal is input to the controller 79 from any one of the sheet material detecting units 26 and 100, the image forming apparatus stops the copying operation.

The sheet material detecting means 26 in the illustrated case is composed of a detecting lever 29 rotatable about the support shaft 27 and an optical sensor 30 for outputting a detecting signal when the detecting lever 29 blocks light. .

The retard roller pair 25 is in contact with the feed roller (normal rotation body) 31 that rotates in the direction (arrow direction) for conveying the sheet material S, and comes into contact with the feed roller 31 at a predetermined pressure to cause the sheet material S to move. And a retard roller (separating rotary body) 32 that rotates in the direction of returning (arrow direction). The retard roller 32 has a roller shaft 42 elastically supported by a spring member (not shown) so that it can move downward in FIG. 1 by a predetermined amount.

The sheet material S fed by the pickup roller 23 to the nip portion of the retard roller pair 25 is 1
If only one sheet is inserted, the retard roller 32 will be in the idle state,
The sheet material S is conveyed downstream by being rotated by the feed roller 31. Further, when a plurality of sheet materials S fed by the pickup roller 23 enter, the retard roller 32
Is rotated in the direction of the arrow, the sheet material S other than the uppermost sheet is returned to the sheet feeding deck 2 by the retard roller 32, and only the uppermost sheet is separated by the feed roller 31 and conveyed downstream.

A pair of retard rollers 25 functioning in this way
The feed roller 31 and the retard roller 32 of FIG.
Rotational power from a drive source such as a motor (not shown) installed in the image forming apparatus main body 1 is transmitted via the power transmission mechanism shown in FIG.

That is, the rotational power of the drive source is transmitted to the roller shaft 36 of the feed roller 31 via the drive belt (endless belt) 33 and the electromagnetic clutch 35. The rotational power transmitted to the roller shaft 36 of the feed roller 31 is transmitted to the relay shaft 39 via the timing belt 37, and further transmitted to the roller shaft 42 of the retard roller 32 via the torque limiter 40 and the coupling 41. ing.

The electromagnetic clutch 35 is arranged at one end of the roller shaft 36, and the rotor shaft 43 is connected to the rotor portion 43. Armature part 45 of electromagnetic clutch 35
Is rotatably mounted on the roller shaft 36, and when a predetermined voltage is applied to the electromagnetic clutch 35, the rotor portion 43
To be integrated with the rotor portion 43. The drive belt 33 is attached to the pulley portion formed on the armature portion 45.
One end of is wrapped around.

Therefore, when a predetermined voltage is applied to the electromagnetic clutch 35, the rotational power of the drive source is transmitted to the roller shaft 36, and the feed roller 31 rotates in the direction in which the sheet material S is conveyed (arrow direction). The electromagnetic clutch 35 is on / off controlled according to the paper feed timing.

Further, the rotation of the roller shaft 36 is transmitted to the relay shaft 39 via the timing belt 37, and further, the roller shaft 4 via the torque limiter 40 and the coupling 41.
2, the retard roller 32 rotates in the direction of returning the sheet material S (arrow direction) in synchronization with the rotation of the feed roller 31.

However, the body 46 of the torque limiter 40 is connected to the relay shaft 39 via a friction member 47 such as magnetic powder,
Since the coupling 41 is connected to the body 46 of the torque limiter 40, when a torque of a predetermined value T or more is applied to the body 46 of the torque limiter 40, a slip state occurs between the body 46 and the relay shaft 39. Occurs. As a result, the retard roller 32 is in the idling state and is driven to rotate by the feed roller 31.

Here, the feed roller 31 and the sheet material S
, And the friction coefficient between the retard roller 32 and the sheet material S is μ1, the friction coefficient between the sheet material S and the sheet material S is μ2, the feed roller 31 and the retard roller 32.
Is R, the feed roller 31 and the retard roller 3 are
When the contact force of 2 is P, μ1, μ2, P, and T are μ1>
By setting μ2 and T / μ1R <P <T / μ2R, one sheet material S enters the nip portion of the retard roller pair 25 and a plurality of sheet materials S enters. , The retard roller 32 will function as described above.

1 and 2, reference numeral 52 denotes a swing arm. The swing arm 52 has a structure in which one end of a pair of substantially L-shaped roller support portions 52a is connected by a beam portion 52b. And the driven roller 5 driven by the other end of the roller support portion 52a.
1 is rotatably attached. In the swing arm 52, the bent portion 52c of the roller support portion 52a is pivotally supported by the swing center shaft 53 attached to the image forming apparatus main body (not shown), and the driven roller 51 faces the retard roller 32. The retard roller 32 is disposed near the retard roller 32. In addition, the swing arm 52 is mounted such that a substantially central portion of the beam portion 52b is attached to an operating shaft portion 54a of an electromagnetic solenoid 54 as an actuator, and is constantly biased in a clockwise direction in FIG. 1 by a retracting spring 55. It has become.

When a voltage is applied, the electromagnetic solenoid 54 moves its operating shaft portion 54a to the left in FIG. 1 against the spring force of the retracting spring 55, so that the swing arm 52 rotates counterclockwise in FIG. Rock in the direction. As a result, the driven roller 51 attached to the swing arm 52 presses the retard roller 32, and the retard roller 32 is separated from the feed roller 31. The electromagnetic solenoid 54 is a controller 79
When the sheet material detecting unit 100 connected to the controller 79 detects a sheet material conveyance defect (jam), the controller 79 performs on / off control.

As described above, the swing arm 52 to which the driven roller 51 on one end side is attached and the electromagnetic solenoid 54 as the actuator constitute the sheet material releasing means 60. Further, the controller 79 has a built-in timer to constitute an operation control means for driving the electromagnetic solenoid 54 and the retard roller 32 for a predetermined time after the jam detection signal is input.

The operation of the sheet feeding device 6 configured as above will be described with reference to FIGS. 1, 3 and 4.

When the image forming start button of the image forming apparatus is pressed, the pickup roller 23 and the feed roller 31
And the retard roller 32 rotates (S1). As a result, only one sheet material S in the paper feed deck 2 is fed into the image forming apparatus. When the sheet material detecting means 100 arranged in the middle of the sheet material conveying path in the image forming apparatus or the sheet material detecting means 26 arranged in the vicinity of the retard roller 32 detects a jam, the detection signal is sent to the controller 79.
And the paper feeding device 6 is controlled by the controller 79 as follows (S2).

First, the rotations of the pickup roller 23, the feed roller 31, and the retard roller 32 are stopped (S3).

Next, the lifter plate 22 of the paper feed deck 2 is lowered (S4), and when the lifter plate 22 is lowered by a predetermined amount (S5), it is detected by a sensor (not shown), and the detection signal is detected by the controller. It is input to 79 and the operation of the lifter plate 22 is stopped by the controller 79 (see FIG. 3).

Next, a voltage is applied to the electromagnetic solenoid 54 (S7), and the electromagnetic solenoid 54 is actuated to swing the swing arm 52, press the driven roller 51 against the retard roller 32, and feed the retard roller 32. Separated from the roller 31. Then, the retard roller 32 is rotated immediately after the operation of the electromagnetic solenoid 54 (S8) (see FIG. 3). The electromagnetic solenoid 54 and the retard roller 32
Is set by a timer (not shown) incorporated in the controller 79, and the sheet is moved by a distance longer than the distance L from the nip portion of the retard roller 32 and the driven roller 51 to the sheet material detecting means 26. The time is set so that the material can be conveyed (S9). Therefore, the residual sheet material S that cannot be detected by the sheet material detection unit 26, that is, the sheet material S that is sandwiched between the retard roller pair 25 without the leading end reaching the sheet material detection unit 26, is reliably stored in the paper feed deck 2. Will be returned. When the residual sheet material S is detected by the sheet material detecting means 26, the presence of the residual sheet material S is indicated on the operation display or the like, and the predetermined jam processing procedure can be transmitted to the user (worker). Therefore, in this case, the normal jam processing is performed.

Next, the rotation of the retard roller 32 is stopped (S10), and the operation of the electromagnetic solenoid 54 is stopped (S11). Therefore, the swing arm 52 is returned to the position shown in FIG.

Next, the lifter plate 22 is raised (S12). When the lifter plate 22 moves up by a predetermined amount (S13), it is detected by a sensor (not shown), and the detection signal is input to the controller 79. Then, the operation of the lifter plate 22 is stopped (S14). As a result, the sheet feeding device 6 returns to the state shown in FIG. 1 and the image can be formed.

Then, the pickup roller 23, the feed roller 31, and the retard roller 32 are operated (S
1) The sheet materials S in the paper feed deck 2 are fed one by one into the image forming apparatus by these rollers 23, 31, 32.

Sheet material detecting means 100 in the image forming apparatus
And sheet material detecting means 26 near the retard roller pair 25
If no jam is detected (S2), a predetermined transfer / fixing operation is performed (S15), and the image forming operation is completed.

As described above, according to this embodiment, when the sheet material S remaining on the retard roller pair 25 is not detected by the sheet material detecting means 26, a jam occurs at a portion other than the retard roller pair 25. Also, the residual sheet material S can be surely returned to the sheet feeding deck 2 by the sheet material releasing means 60. Therefore, even when the paper feeding operation is restarted after the jam processing, a new jam due to the residual sheet material S is not generated in the retard roller pair 25 portion, and the good paper feeding operation can be restarted. . Further, in the present embodiment, by disposing the sheet material releasing means 60 in the vicinity of the retard roller pair 25, it is possible to remove the residual sheet material S of the retard roller pair 25 by using the normal return drive of the retard roller 32. Therefore, it is not necessary to add a return-dedicated roller to the pickup roller (paper feeding unit) 23, and an inexpensive and highly reliable paper feeding device can be provided without significantly changing the original configuration.

FIG. 5 shows an image forming apparatus (copying machine) provided with this retard separation type sheet feeding device.

The image forming apparatus comprises a paper feed deck 2 in which a large amount of sheet materials S are stacked and stored on one side of the image forming apparatus main body 1.
In addition to the above, a plurality of paper feed cassettes 3 and 5 in which a predetermined amount of sheet materials S are stacked and stored are provided in the lower portion inside the image forming apparatus main body 1.

The sheet feeding deck 2 as a sheet feeding portion for feeding the sheet material S and the sheet feeding cassettes 3 and 5 are provided with retard separating type sheet feeding devices 6 and 7, respectively. 9 is provided.

When the sheet materials S in the sheet feeding deck 2 and the sheet feeding cassettes 3 and 5 are fed by the sheet feeding devices 6, 7 and 9, first, the registration roller pair 1 which is stopped rotating.
0, where the skewed state is corrected.

Next, the sheet material S is sent between the photosensitive drum 11 and the transfer charger 12 by the registration roller pair 10 which rotates at a timing with the latent image formed on the photosensitive drum 11. Here, the toner image on the photosensitive drum 11 is transferred (image formation).

After that, the sheet material S is sent to the fixing device (fixing roller pair) 15 by the conveyor belt 13 and a fixing process for fixing the toner image transferred here to the sheet surface is performed.

The image forming apparatus is provided with a double-sided copy mode for performing double-sided copy on the sheet material S and a multiplex copy mode for performing multiplex copy. In the normal copy mode, the sheet material S after fixing processing is Paper is discharged onto a paper discharge tray 19 outside the apparatus by the paper discharge roller pair 16 and the external paper discharge roller pair 17.

In the double-sided copying mode and the multiplex copying mode, the sheet material S is temporarily placed on the intermediate tray 21 via the re-feeding path 20 by the inner paper discharging roller pair 16 or the outer paper discharging roller pair 17. It is loaded and stored.

Although the sheet feeding cassettes 3 and 5 are front-loaded, the sheet feeding devices 7 and 9 provided at the installation site have the same structure as the sheet feeding device 6. Therefore, as in the case of the above-described paper feeding device 6, the paper feeding devices 7 and 9 do not cause the residual sheet to be jammed or damaged.

As described above, in the image forming apparatus using the sheet feeding device 6 of the above-described embodiment, when the sheet feeding operation is started again after the occurrence of the jam, the jamming of the retard roller pair 25 portion due to the residual sheet material S is performed. Since the generation is prevented, the image formation is smoothly performed by the image forming means including the transfer charger 12 and the fixing device 15, and the reliability of the apparatus is improved.

FIG. 6 shows another embodiment of the sheet feeding device 6 of the present invention. Further, FIG. 7 shows a control state of the sheet feeding device 6.

In the present embodiment, as shown in FIG. 6, if a sheet material detecting means 26 is further added upstream of the retard roller pair 25 in the sheet material conveying direction in addition to the sheet feeding apparatus of the above embodiment, The electromagnetic solenoid 54 and the retard roller 32 until the sheet material detecting means 26 detects the absence of the sheet material.
Continues the drive (S9 ₁₎ (see FIG. 7), so-called,
It is possible to drive the sensor as a reference, and to provide a reliable residual sheet material removal method.

In each of the above embodiments, the electromagnetic solenoid 54 is shown as the actuator, but the actuator is not limited to this, and may be a combination of a motor and a rack and pinion. Further, although the controller 79 with a built-in timer is shown as the operation control means, the invention is not limited to this, and a timer may be provided separately from the controller 79, and the operation control means may be configured by these separate timers and the controller 79. Further, the forward rotation body and the separation rotation body are not limited to rollers, but may be belts.

[0069]

As is apparent from the above description, in the sheet feeding device of the present invention, the sheet material S remaining in the retard roller pair portion is not detected by the sheet material detecting means, and the sheet material S is removed from the portion other than the retard roller pair. Even if a jam occurs, the residual sheet material can be surely returned to the sheet feeding deck by the sheet material releasing means. Therefore, even when the paper feeding operation is restarted after the jam processing, a new paper jam or sheet material damage due to the residual sheet material does not occur in the retard roller pair portion, and the good paper feeding operation can be restarted. To Further, in the sheet feeding device of the present invention, by disposing the sheet material releasing means in the vicinity of the pair of retard rollers, it is possible to remove the residual sheet material of the pair of retard rollers by using the normal return drive of the retard roller. Therefore, it is not necessary to add a roller dedicated to the return to the pickup roller (paper feeding unit), and an inexpensive and highly reliable paper feeding device can be provided without significantly changing the original configuration.

Further, since the image forming apparatus of the present invention is provided with the above-mentioned paper feeding device, when the paper feeding operation is restarted after the occurrence of the jam, a new jam or damage to the sheet material occurs at the retard roller pair portion. Therefore, the reliability of the device can be improved.

[Brief description of drawings]

FIG. 1 is a side view of a sheet feeding device according to an embodiment of the present invention.

FIG. 2 is a perspective view of a main part (paper feeding unit) of the paper feeding device.

FIG. 3 is an operation state diagram of sheet material releasing means of the paper feeding device.

FIG. 4 is a flowchart showing an operating state of the paper feeding device.

FIG. 5 is a cross-sectional view of an image forming apparatus including the paper feeding device.

FIG. 6 is a side view of a paper feeding device according to another embodiment of the present invention.

FIG. 7 is a flowchart showing an operating state of the paper feeding device.

FIG. 8 is a side view of a conventional paper feeding device.

FIG. 9 is a perspective view showing a power transmission mechanism of the paper feeding device.

FIG. 10 is a view showing an operating state of a sheet material detection unit of the paper feeding device.

FIG. 11 is a view showing a non-operating state (state of residual sheet material) of the sheet material detecting means of the paper feeding device.

FIG. 12 is a defective deformation state diagram of the residual sheet material at the start of re-feeding of the paper feeding device.

[Explanation of symbols]

 1 image forming apparatus main body 2 sheet material storage device (paper feeding deck) 6 paper feeding device 23 pickup roller 26 sheet material detecting means 31 feed roller 32 retard roller 51 driven roller 52 swinging arm 54 actuator (electromagnetic solenoid) 60 sheet material release Means 79 Operation control means (CPU) S Sheet material

Claims (7)

[Claims] 1. A pickup means for feeding a sheet material from a sheet material storage device in which a plurality of sheet materials are stacked and stored, a forward rotation body rotating in a sheet material conveying direction, and a forward rotation body. On the other hand, it is composed of a separating rotary member that can rotate in the opposite direction, and only one of the sheet materials fed from the pickup means is conveyed into the main body of the image forming apparatus, and the other sheet material is stored in the sheet material storage device. And a separating unit for returning the separating unit, which is arranged in the vicinity of the separating unit and separates the normal rotating body and the separating rotating body of the separating unit when the conveyance failure detection signal is input. A sheet feeding device comprising a sheet material releasing means for rotating a body in a reverse direction to return the sheet material in the separating means into the sheet material storing device. 2. A pickup roller for feeding a sheet material from a sheet material storage device in which a plurality of sheet materials are stacked and stored, and the sheet material fed from the sheet material storage device by the pickup roller. And a feed roller that conveys the sheet material into the main body of the image forming apparatus and forms a nip portion between the feed roller and the feed roller. In this case, the feed roller rotates in the direction opposite to the conveying direction to separate the sheet material into one sheet material, while when the number of the sheet material fed from the sheet material storage device is one, the feed roller And a retard roller that rotates in the conveying direction to convey the sheet material, and a feeding failure detection signal is provided in the vicinity of the retard roller. When input, separates the retard roller from the feed roller, allowing the retard roller to rotate in the direction opposite to the feed roller conveying direction, and pressing the sheet material located between the retard roller and the feed roller against the retard roller. A sheet feeding device comprising a sheet material releasing means for returning the sheet material into the sheet material storing device in the above state. 3. The sheet material releasing means is connected to an oscillating arm having a driven roller attached at one end side, and is connected to the oscillating arm, and moves the oscillating arm when a conveyance failure detection signal is input to the driven roller. 3. The actuator for pressing the retard roller into contact with the retard roller, separating the retard roller from the feed roller, and enabling the retard roller to rotate in the direction opposite to the feeding direction of the feed roller. Paper feeder. 4. The sheet feeding device according to claim 2, further comprising an operation control unit that drives the actuator and the retard roller for a predetermined time after the conveyance failure detection signal is input. . 5. A sheet material detecting means is provided on a downstream side of the retard roller in the sheet material conveying direction, and a returning amount of the sheet material by the retard roller is larger than a distance from the sheet material detecting means to the retard roller. 5. The sheet feeding apparatus according to claim 4, wherein the actuator and the retard roller are operated by the operation control means. 6. A sheet material detecting means is provided on the upstream side of the retard roller in the sheet material conveying direction, and the operation control means operates the actuator and the actuator until the sheet material detecting means detects the absence of the sheet material after the conveyance failure detection signal is input. The sheet feeding device according to claim 4 or 5, wherein a retard roller is operated. 7. The method according to any one of claims 1 to 6.
An image forming apparatus, comprising: the sheet feeding device according to the item 1; and an image forming unit that forms an image on a sheet material fed by the sheet feeding device.