JP2001302006A - Paper feeder and image forming device having the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a paper feeder that can receive an insertion of more sheets without causing double feeding and can accommodate an insertion and withdrawal of sheets without damaging the sheets and a paper feed roller, and an image forming device having the paper feeder. SOLUTION: An interlocking means 36, 37, 40 interlocks a separating slant moving action of a separating slant moving means 34 and a feeding means moving action of a feeding means moving means 38. In paper feeding, a feeding means 19 for delivering sheets S stored in a sheet storing means 32 is moved to a position to press against the sheets S, and a separating slant 33 turnably arranged at the lower end of the sheet storing means 32 is moved to a position to separate the sheets S delivered by the feeding means 19, one from the next. After the paper feeding, the feeding means 19 is moved to a position to stay away from the sheets S, and the separating slant 33 is moved to a position to stop the sheets S.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeder and an image forming apparatus having the same, and more particularly to a sheet feeder that separates sheets by using a separation slope.

[0002]

2. Description of the Related Art Conventionally, an image forming apparatus is provided with a sheet feeding device for feeding a sheet to an image forming section.
As such a sheet feeding apparatus, there is, for example, a slope separation type in which sheets are separated using a separation slope.

FIG. 7 is a diagram showing a schematic configuration of an image forming apparatus provided with such a conventional sheet feeding apparatus. In FIG. 7, reference numeral 100 denotes an image forming apparatus, and 101 denotes a sheet feeding apparatus.
Here, the sheet feeding device 101 stacks the sheets S as shown in the figure, and also includes a sheet feeding tray 16 having a sheet feeding tray 32 having a separation slope 33 formed at a lower end, and a sheet feeding tray 32. And a sheet feeding unit 15 for sequentially feeding the fed sheets S.

[0004] The paper feed section 15 is composed of a feed section 17 and a transport section 18. Here, the feeding unit 17
A feed roller 19 that rotates integrally with the gear 19a, and an idler gear A20 that meshes with the gear 19a of the feed roller 19
And an idler gear B21 meshing with the idler gear A20
, A drive gear 22 that meshes with the idler gear B21, a drive shaft 23 to which the drive gear 22 is attached, and a paper feed roller 19, an idler gear A20, an idler gear B21, and the drive gear 22 are rotatably supported, and the drive shaft 23 And a paper feed roller holder 24 rotatably attached to the paper feed roller holder 24.

[0005] The transport section 18 includes a lower guide 26 and an upper guide 27 for guiding the sheet S fed by the feed section 17, a transport roller 28 for transporting the fed sheet S in a predetermined direction, and A transport roller 29 arranged opposite to the transport roller 28; a roller holder 30 rotatably supported by the upper guide 27 via a rotating shaft 30a while rotatably supporting the transport roller 29; 29
And a transfer spring 31 that urges the roller holder 30 so as to press the transfer roller 28 against the transfer roller 28.

[0006] Then, the paper feeder 101 having such a configuration is used.
When the sheet feeding operation is performed, first, the drive shaft 23 is rotated by a drive mechanism (not shown) that is driven and controlled by a control unit (not shown) that controls start and stop of the sheet feeding operation.

Here, when the drive shaft 23 rotates in this way, this rotation is transmitted to the paper feed roller 19 via the drive gear 22, idler gear B21, and idler gear A20.
The paper feed roller 19 starts rotating. Note that the paper feed roller 19
Is rotatably held by a biasing means (not shown) or its own weight in a direction that rotates counterclockwise around the drive shaft 23. The paper feed roller 19 is lightly pressed against the upper surface of the uppermost sheet (hereinafter, referred to as the uppermost sheet) S1 of the sheets S stacked on the paper feed tray 32.

As a result, when the paper feed roller 19 starts rotating, a feed force is exerted on the uppermost sheet S1 by the frictional force of the paper feed roller 19. Here, when such a feeding force is applied, the uppermost sheet S1 is bent by receiving a reaction force from the separation slope 33, whereby the sheet S1 is bent.
With the leading end abutting on the separation slope, the sheet proceeds in a bent state and is separated from other sheets.

The uppermost sheet S1 separated from the other sheets in this manner has its traveling direction determined by an upper guide 27 and a lower guide 26, and is conveyed by a conveying spring 31 urged toward a conveying roller 28. 29 and transport roller 28
And into the nip formed by
8 transports further downstream.

[0010]

However, in such a conventional sheet feeding apparatus, when the sheets S are inserted into the sheet feeding tray 32 from above in order to replenish the sheets S, the sheets S are inserted into the separation slope 33. Hits strongly. Here, since the separation slope 33 is inclined with respect to the sheet insertion direction as shown in the figure, when the sheet S is inserted vigorously in this manner, the leading end of the sheet S is moved as shown in FIG. It will be deformed. When the leading end portion is deformed in this way, the sheet separating action of the separation slope 33 may be reduced, and double feeding of the sheet S may occur.

Further, when many sheets S are vigorously inserted into the sheet feed tray 32 at a time, many of the sheets S slip without stopping at the separation slope 33 due to deformation of the leading end of the sheets S. It may not be possible to load.

On the other hand, when the sheet S is inserted into the sheet feeding tray 32, the sheet feeding roller 19 is in a state of being lowered as shown in FIG. I will hit you. If the leading end of the sheet S hits the sheet feeding roller 19 in this way, it becomes difficult to insert the sheet S, and the leading end of the sheet S and the sheet feeding roller 19 may be damaged.

Further, if the sheet feeding roller 19 is kept lowered, for example, when another sheet is used, the sheet S stacked on the sheet feeding tray 32 is also taken out. Since the sheet feeding roller 19 is kept pressed against the sheet S, it is difficult to take out the sheet S.

Therefore, the present invention has been made in view of such a situation, and it is possible to insert more sheets without causing double feeding, and to damage the sheets and the sheet feeding roller. It is another object of the present invention to provide a sheet feeding device capable of inserting and extracting a sheet and an image forming apparatus including the sheet feeding device.

[0015]

SUMMARY OF THE INVENTION The present invention relates to a sheet feeding device for separating and feeding sheets stored one by one in a state inclined to the sheet storage means. A feeding means for feeding, a separating slope which is rotatably provided at a lower end portion of the sheet storing means, and separates the sheets fed by the feeding means one by one; and Separating slope moving means for selectively moving a sheet to a first position for separating the sheet and a second position for locking the sheet; and separating the sheet feeding means from the first position for pressing the sheet against the sheet and the sheet. Feeding means moving means for selectively moving to a second position to be moved; interlocking means for interlocking the separating slope moving operation of the separating slope moving means with the feeding means moving operation of the feeding means moving means; Be prepared The separating slope moving means and the feeding means moving means are linked by the interlocking means to move the feeding means and the separating slope to the first position when feeding paper, and to move the feeding slope and the separating slope to the first position when feeding paper. The feeding means and the separation slope are each configured to be moved to the second position.

Further, in the present invention, the separating slope moving means and the feeding means moving means are interlocked by the interlocking means so that the feeding means is moved to the first position when feeding paper, and then the separation is performed. Moving the slope to the first position, moving the separation slope to the second position except for paper feeding, and then moving the feeding means to the second position. It is characterized by the following.

According to the present invention, there is provided an image forming apparatus comprising an image forming unit and a sheet feeding device for feeding a sheet to the image forming unit, wherein the sheet feeding device is as described above. It is characterized by having.

[0018]

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

FIG. 1 is a diagram showing a schematic configuration of an image forming apparatus provided with a sheet feeding device according to a first embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes an image forming apparatus, and 1A denotes an image forming apparatus main body (hereinafter, referred to as an apparatus main body). The image forming apparatus 1 includes an image forming section 3 for forming an image on a sheet S; A sheet feeding device 2 for feeding the sheet S to the image forming unit 3, a fixing device 9 for fixing the image formed on the sheet S by the image forming unit 3, and a discharging unit for discharging the sheet S on which the image is fixed 4 and sheet stacking means 5 for stacking the discharged sheets S.

Here, the image forming section 3 includes a photosensitive drum 7 having a photosensitive layer on the surface, a charging roller 10 as charging means for uniformly charging the surface of the photosensitive drum 7 by applying a voltage, A developing means 11 for developing a latent image formed on the photosensitive drum by exposure by the means 6 with a developer (hereinafter, referred to as toner); and a toner image developed by the developing means 11 and formed on the photosensitive drum 7. A transfer roller 8 for transferring the toner image to the sheet S, and a cleaning unit 1 for scraping off the toner remaining on the surface of the photosensitive drum 7 after transferring the toner image to the sheet S by the transfer roller 8
2 and a waste toner container 13 for collecting the scraped toner
And Reference numeral 14 denotes a process cartridge provided integrally with the photosensitive drum 7, the charging roller 10, the developing unit 11, the cleaning unit 12, and the waste toner container 13.

Next, an image forming operation of the image forming apparatus 1 configured as described above will be described.

When an image is formed, first, a light image based on the target image information is formed by an exposure means 6 such as a slit image projection means and a laser scanning exposure means for a document image (not shown) on a photosensitive drum 7 serving as an image carrier. To form a latent image on the photosensitive drum. Next, the latent image is developed by the developing means 11 to form a toner image on the photosensitive drum.

On the other hand, a sheet S is fed from the sheet feeding device 2 to the nip between the photosensitive drum 7 and the transfer roller 8 in synchronization with the formation of the toner image. Is transferred by the transfer roller 8. Thereafter, the sheet S to which the toner image has been transferred is fixed to the fixing rotator 9 a and the fixing rotator 9
The toner image is fixed by the fixing device 9 including the driving roller 9b that is in pressure contact with the toner image a. Further, after the toner image is fixed as described above, the sheet S is discharged to the sheet stacking unit 5 by the discharging unit.

FIG. 2 is a view for explaining the configuration of the sheet feeding device 2. The sheet feeding device 2 includes a sheet feeding tray 16 for stacking sheets S and a sheet feeding tray as shown in FIG. And a sheet feeding unit 15 for sequentially feeding the sheets S stacked on the unit 16. Reference numeral 45 denotes a manual paper feed unit.

Further, the paper supply section 15 includes a paper supply roller 19, which is a paper supply means, an idler gear A20, an idler gear B21, a drive gear 22, a drive shaft 23, and a paper supply roller holder 24. Lower and upper guides 26, 27,
The transport unit 28 includes a transport roller 28, a transport roller 29, a roller holder 30, and a transport spring 31. The paper feed roller holder 24 is provided with an arm portion 24a. As described later, by pressing this arm portion 24a, the paper feed roller holder 24 moves clockwise around the drive shaft 23 as a fulcrum. It is designed to rotate.

On the other hand, the paper feed tray section 16 includes a paper feed tray 32 which is a sheet storage means for storing the sheets S in an inclined state, a movable separation slope 33, a first cam 34, a first roller 36, and a belt 37. , A second cam 38 and a second roller 40.

Here, the movable separation slope 33 is provided on the sheet feeding tray 3.
The first cam 34 rotates together with a first camshaft 35 provided on the apparatus main body 1A to form a movable separation slope 33 at a lower end portion of the second rotation shaft 33 so as to be rotatable around a rotation shaft 33a. It constitutes separating slope moving means for selectively moving. The first roller 36 is mounted on the first cam shaft 35 coaxially with the first cam 34.

Further, the second cam 38 rotates together with the second cam shaft 39 provided on the apparatus main body 1A, and selectively moves the paper feed roller 19 by pressing the arm 24a of the paper feed roller holder 24. The second roller 40 is mounted on the second cam shaft 39 coaxially with the second cam 38.

The belt 37 is made up of the first roller 36 and the second roller 36.
The first roller 36, the second roller 40, and the belt 37 constitute an interlocking means for interlocking the first cam 34 and the second cam 38 with the roller 40 and an appropriate tension. By configuring the interlocking means in this way, the rotation of the first camshaft 35 causes the first camshaft 35 to rotate.
When the cam 34 rotates, the second cam 38 rotates simultaneously. The first camshaft 35 is driven to rotate by a drive device (not shown) controlled by control means (not shown), and makes one rotation during the sheet feeding operation.

FIG. 4 shows a state before the sheet feeding operation is performed. At this time, the first cam 34 is in a position where the movable separation slope 33 is pushed up, and thereby the movable separation slope 33 is moved to the sheet S. Has been moved to a position substantially perpendicular to the insertion direction (hereinafter, referred to as a home position).

When the movable separation slope 33 is at the home position, which is the second position, the sheet S
Is locked without slipping by the movable separation slope 33, so that even when the sheet S is inserted vigorously, the sheet S can be prevented from being deformed.

At this time, the second cam 38 is located at a position (hereinafter, referred to as a home position) for pressing the arm portion 24a of the sheet feeding roller holder 24.
By pressing 4a, the paper feed roller holder 24 rotates clockwise.

The paper feed roller holder 24
Is rotated clockwise, so that the paper feed roller 1
Numeral 9 moves to a position sufficiently distant from the sheets S stacked on the sheet feed tray 32. That is, when the second cam 38 is at the home position, the paper feed roller 19 moves to the second position apart from the sheet S.

On the other hand, when the first camshaft 35 rotates and the first cam 34 rotates counterclockwise, the movable separation slope 33 rotates downward by its own weight, and the lower guide 26 as shown by a broken line.
And moves to a first position (hereinafter, referred to as a separation position) where the sheet is separated by forming substantially the same surface as the sheet. At the same time, the second cam 38 via the first roller 36 and the second roller 40.
Is rotated, whereby the arm portion 24 by the second cam 38 is rotated.
The pressing on a is released.

As a result, the paper feed roller holder 24 rotates counterclockwise by its own weight, and the paper feed roller 19 is brought into contact with the sheet S stacked on the paper feed tray 32 at the first position. To move to. And
The top sheet S1 is sent out to the conveyance section 18 by rotating the sheet feeding roller 19 in a state of being pressed against the sheet S in this manner.

Next, the paper feeding operation of the paper feeding device 2 configured as described above will be described.

Before performing the feeding operation, the movable separation slope 33 is pushed up by the first cam 34 and moved to the home position which is substantially perpendicular to the sheet inserting direction.
As a result, the sheet S stops in a state in which the sheet S abuts on the movable separation slope 33 without slipping and without deforming the leading end. Further, the second cam 38 is at a home position for pressing the arm portion 24a of the paper feed roller holder 24, whereby the paper feed roller 19 and the paper feed roller holder 24 move to positions sufficiently separated from the sheet S. ing.

When the sheet feeding operation is started in this state, the control means controls the driving of the driving means to rotate the first cam shaft 35. And, as described above, the first camshaft 35
Rotates, the first cam 34 starts to rotate counterclockwise, and accordingly, the movable separation slope 33 rotates downward by its own weight and moves to the separation position.

The second cam 38 also rotates with the rotation of the first cam shaft 35, whereby the pressing against the arm portion 24a is released, whereby the paper feed roller holder 24 is lowered by its own weight and the paper feed roller 19 Presses against the uppermost sheet S1. Thereafter, when the movable separation slope 33 moves to the separation position, the control means temporarily stops the first cam shaft 35 and rotates the drive shaft 23 to rotate the paper feed roller 19. Thereby, the top sheet S1 is
After being separated from other sheets by the movable separation slope 33 moved to the separation position, the sheet is conveyed by the conveyance unit 18.

On the other hand, when the uppermost sheet S1 is separated and conveyed, and this uppermost sheet S1 is detected by the detecting means (not shown), the control means drives the first cam shaft 35 again based on a detection signal from the detecting means. I do. Thus, the first cam 34 starts to push up the movable separation slope 33, and the second cam 38 starts to push the arm 24a.

When the paper feeding operation is completed, that is, the first
When the cam shaft 35 makes one rotation, the movable separation slope 33 and the second
Each of the cams 38 returns to the home position, whereby the sheet S is locked on the movable separation slope 33 without slipping, and the sheet feeding roller 19 and the sheet feeding roller holder 24 are sufficiently separated from the stacked sheets S. Move to a place. This operation is repeated for each sheet feeding operation.

After the above-described sheet feeding operation is completed or when the sheet feeding operation is not performed, the movable separating slope 3
Since 3 is at the home position, even if the user vigorously inserts the sheet S into the sheet feeding tray 32 to replenish the sheet S, the leading end of the sheet S abuts the movable separation slope 33 almost perpendicularly, so that the sheet S is not deformed. Absent. This can prevent double feeding due to deformation of the sheet S when the sheet is inserted.

When the sheet feeding operation is not performed, since the sheet feeding roller 19 is located at a position far from the sheet S, when the user inserts the sheet S into the sheet feeding tray 32, the leading end of the sheet S is fed. Since the sheet S does not hit the roller 19, the sheet S can be easily inserted and the sheet S and the sheet feeding roller 19 can be prevented from being damaged. Further, even when the sheet S is pulled out, the sheet S does not hit the paper feed roller 19, so that the sheet S can be easily pulled out.

Further, in the case of this embodiment, the paper feed roller 19 is separated from the sheet S immediately after the separation and conveyance of the sheet S. For this reason, during the subsequent sheet conveyance, the back tension by the sheet feeding roller 19 does not occur, and thereby the stable conveyance of the sheet S can be realized.

As described above, when the paper feed roller 19 is pressed against the sheet S after the movable separation slope 33 is moved to the separation position, the timing at which the paper feed roller 19 is pressed against the sheet S depends on the timing. The tip of the sheet S may slide on the movable separation slope 33 and be deformed by a shock when the movable separation slope 33 moves.

In order to prevent such deformation of the sheet S, first, the sheet feeding roller 19 is pressed against the sheet S,
Thereafter, it is preferable to move the movable separation slope 33 to the separation position.

Next, a description will be given of a second embodiment of the present invention in which the movable separation slope 33 is moved to the separation position after the sheet supply roller 19 is pressed against the sheet as described above.

FIG. 3 is a diagram showing a configuration of the sheet feeding device according to the present embodiment. 2, the same reference numerals as those in FIG. 2 indicate the same or corresponding parts.

In the figure, reference numerals 34A and 38A denote a first cam and a second cam, respectively.
A and 38A are formed in such a shape that the movable separation slope 33 is moved to the separation position after the paper feed roller 19 is pressed against the sheet S.

Next, the sheet feeding operation of the sheet feeding device 2 according to the present embodiment will be described.

Before the paper feeding operation, the first cam 34A pushes up the movable separation slope 33, as shown in the figure, whereby the movable separation slope 33 is located at the home position. The second cam 38A is connected to the sheet feed roller holder 24.
Is positioned at a home position where the arm 24a is pressed, whereby the sheet feeding roller 19 is located sufficiently away from the sheet S.

When the sheet feeding operation is started, the first cam shaft 35 starts rotating, and accordingly, the first cam 34A and the second cam 38A start rotating in the direction of the arrow as shown in FIG. . When the first cam 34A and the second cam 38A rotate in this way, in the present embodiment, the first cam 34A and the second cam 38A
Depending on the shape of the cam 34A and the second cam 38A,
Arm 24 of paper feed roller holder 24 by cam 38A
a is released. As a result, the paper feed roller holder 24 is rotated downward by its own weight, and the paper feed roller 19 is pressed against the sheets S stacked on the paper feed tray 32 as shown in FIG.

Further, when the first camshaft 35 rotates, next, the lifting of the movable separation slope 33 by the first cam 34A is released. Thereby, the movable separation slope 33 rotates in the direction of the arrow due to its own weight, and moves to the separation position as shown in FIG.

After the movable separating slope 33 is moved to the separating position, the control means stops the first cam shaft 35 and rotates the driving shaft 23 to rotate the sheet feeding roller 19. ing. As a result, the uppermost sheet S <b> 1 is abutted against the movable separation slope 33 and separated, and then conveyed by the conveyance unit 18.

After the lowermost sheet S1 is conveyed in this way, when the first cam shaft 35 is rotated again, the first cam 34A starts to push up the movable separation slope 33, whereby the movable separation slope 33 rotates upward. To move to the home position as shown in FIG. After this, the second cam 38
A moves to a home position where the arm portion 24a of the paper feed roller holder 24 is pressed, whereby the paper feed roller 19 is moved.
Moves away from the sheet and returns to the state of FIG.
The operation described above is repeated for each feeding operation.

As described above, the sheet feeding roller 19 always presses the sheet S when the movable separation slope 33 moves, so that the leading end of the sheet S is moved by the shock when the movable separation slope 33 moves. It is possible to prevent deformation by sliding on the upper surface 33.

[0058]

As described above, according to the present invention, the feeding means is separated from the sheet at a position other than the sheet feeding.
In addition, by moving the separation slope to the position where the sheet is locked, it is possible to prevent the front end of the sheet from being deformed even if the user inserts the sheet vigorously, thereby preventing the occurrence of double feeding. In addition, more sheets can be inserted, and sheets can be inserted or pulled out without damaging the sheets or the sheet feeding roller.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a schematic configuration of an image forming apparatus including a sheet feeding device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of the paper feeding device.

FIG. 3 is a diagram illustrating a configuration of a sheet feeding device according to a second embodiment of the present invention.

FIG. 4 is a diagram illustrating a first operation of the paper feeding device.

FIG. 5 is a diagram illustrating a second operation of the paper feeding device.

FIG. 6 is a diagram illustrating a third operation of the paper feeding device.

FIG. 7 is a diagram illustrating a schematic configuration of an image forming apparatus including a conventional sheet feeding device.

FIG. 8 is a diagram illustrating a configuration of a conventional sheet feeding device.

FIG. 9 is a diagram showing a state when sheets are supplied to the conventional sheet feeding device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Paper feeder 3 Image forming part 19 Paper feed roller 23 Drive shaft 24 Paper feed roller holder 24a Arm part 32 Paper feed tray 33 Movable separation slope 34, 34A First cam 36 First roller 37 Belt 38, 38A 2nd cam 40 2nd roller S sheet

Claims (3)

[Claims] 1. A sheet feeding device for separating and feeding sheets stored one by one in a state inclined to a sheet storage means, a feeding means for feeding out the sheets stored in the sheet storage means, and the sheet A separating slope, which is rotatably provided at a lower end portion of the storage means and separates sheets fed by the feeding means one by one,
Separating slope moving means for selectively moving the fed sheet to a first position for separating the fed sheet and a second position for locking the sheet; and a first position for pressing the feeding means against the sheet. Feeding means moving means for selectively moving the sheet and the second position apart from the sheet; interlocking the separating slope moving operation of the separating slope moving means with the feeding means moving operation of the feeding means moving means. Interlocking means for causing the separation slope moving means and the feeding means moving means to interlock with the interlocking means to move the feeding means and the separation slope to the first position when feeding paper, respectively. A sheet feeding device configured to move the feeding means and the separation slope to the second position, respectively, except when the sheet is fed. 2. The separating slope moving means and the feeding means moving means are linked by the interlocking means to move the feeding means to the first position when feeding paper, and then move the separating slope to the first position. Moving the feeding unit to the second position after moving the separation slope to the second position when the sheet is moved to the first position and other than paper feeding. The sheet feeding device according to claim 1, wherein 3. An image forming apparatus comprising: an image forming unit; and a sheet feeding device for feeding a sheet to the image forming unit, wherein the sheet feeding device is the one according to claim 1 or 2. Characteristic image forming apparatus.