JP2006137578A - Paper feeding device and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper feeding device capable of using a common device even if installation places and kinds of papers to be handled differ and being miniaturized. <P>SOLUTION: In this paper feeding device for separating only one paper from papers loaded for feeding by suction of air and supplying and conveying it, belts 4a, 4b, 4c, 4d provided with a suction hole 11 for sucking air for attaching a paper and power transmission means for giving belt driving force to the belts 4a, 4b, 4c, 4d are provided and arranged only above the papers loaded for feeding. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a paper feeding device installed in an image forming apparatus such as a facsimile machine, a printer, a copier, and a printing machine. In particular, a common device can be used even if the installation location and the type of paper to be handled are different. In addition, the present invention relates to a paper feeding device that can be miniaturized.

A paper feeding device provided in an image forming apparatus such as a copier or a printer often employs a friction method as a mechanism for efficiently separating paper fed from a paper bundle. However, in the friction method, a great amount of slip occurs during sheet separation, and there is a limit to high-precision conveyance of the sheet. On the other hand, in the paper separation / conveying operation, a technique has been proposed in which the paper is sucked with air to be separated and conveyed.
For example, in the technique of Patent Document 1, the uppermost transfer paper in the bundle of transfer papers stacked on the paper feed tray is lifted, and the lifted transfer paper is sucked to the perforated conveyance belt paper feed surface by a single fan. As a result, cost reduction and device capacity reduction can be achieved. In the technique of Patent Document 2, an air layer is formed by air blowing means in an area where the suction force by the paper feed roller reaches, and the air rotates while having the effect of blocking the influence of the suction force on the second and subsequent sheets. It is said that the sheet separation performance can be remarkably improved by two synergistic effects that the second and subsequent sheets are peeled off by the separation roller.
JP 2004-137017 A JP 2004-91212 A

However, in the conventional paper feeding device, for example, the paper feeding device in the multi-stage paper feeding (bank) unit and the paper feeding device in the manual feeding unit are different in the paper feeding port direction, or the separated paper feeding conveyance direction is turned vertically. Since the layout of the separation unit of the sheet feeding device is different from the case where it is performed as it is or the layout (space) of the sheet feeding device is different, the device configuration cannot be shared and the devices cannot be shared. Further, since the members constituting the paper feeding device are arranged not only above but also below the paper to be fed, not only the paper feeding device is downsized but also the image forming apparatus including the paper feeding device is downsized. It was also an obstacle. In addition, although there is a strong tendency to demand thick paper as the paper to be used by colorization, it has been difficult for the conventional paper feeding method to handle thin paper to thick paper with the same paper feeding method.
Accordingly, the present invention has been made in consideration of the above-described circumstances, and provides a paper feeding device that can use a common device and can be downsized even if the installation location and the type of paper to be handled are different. The purpose is to do.

In order to solve the above-described problem, the invention according to claim 1 is a paper feeding device that separates and conveys only the topmost sheet from a stack of stacked sheets by air suction. A plurality of endless belts having air suction holes for adsorbing air and arranged adjacent to each other in a line along the paper conveyance direction; and power transmission means for applying belt driving force to the belts. And disposed only above the sheet bundle.
According to a second aspect of the present invention, in the paper feeding device according to the first aspect, the plurality of belts are configured to be changeable to a flat positional relationship and a bent positional relationship, and each belt is configured to suck and convey paper. It is characterized in that the adsorbed paper and other paper are separated by performing a waving operation.
According to a third aspect of the present invention, there is provided the paper feeding device according to the first or second aspect, further comprising control means for changing the undulating operation according to the type of paper.
According to a fourth aspect of the present invention, there is provided a paper feeding device that separates and conveys only one sheet from the stacked paper bundle by air suction, and includes a plurality of air suction holes for sucking paper. An endless belt, a power transmission means for applying a belt driving force to each belt, and a rotational force applying means for rotating the belt with respect to the other belts. A plurality of the belts are connected so as to be continuous along the sheet conveyance direction so that the direction of the path can be freely set, and is arranged only above the sheets stacked for the sheet feeding.
According to a fifth aspect of the present invention, in the paper feeding device according to the fourth aspect, the width of the device is configured to be within the range of the width of the minimum size paper.
According to a sixth aspect of the present invention, in the paper feeding device according to the fourth or fifth aspect, it can be used in common for all the paper feeding ports of the image forming apparatus to be mounted.
According to a seventh aspect of the present invention, in the paper feeding device according to the fourth, fifth, or sixth aspect, each belt separates the adsorbed paper and the other paper by performing a wave motion when sucking and conveying the paper. It is characterized by.
According to an eighth aspect of the present invention, in the paper feeding device according to the fourth, fifth, sixth, or seventh aspect, the paper feeding device further includes a control unit that changes the undulating operation according to the type of paper.
A ninth aspect of the invention is characterized by comprising the paper feeding device according to any one of the first to eighth aspects.

According to the present invention, since the paper feeding device is installed only above the paper set for paper feeding, the space for separating the paper is greatly reduced, and not only the device can be downsized but also mounted. This also contributes to downsizing of the image forming apparatus. In addition, because paper is adsorbed by air and separated by undulating action, there is no stress on the surface of the paper, and the effect on the next process (image forming unit) is reduced, enabling good image formation. Therefore, the sheet can be conveyed with high accuracy.
In addition, since the waving operation can be changed according to the type of paper, it is possible to cope with the state of the paper and widen the width of the corresponding paper type. In addition, since a plurality of belts are connected so as to be continuous along the paper conveyance direction, and each belt can be bent with respect to the adjacent belt, it is not affected by the layout of the paper feed separation conveyance unit such as horizontal conveyance and vertical conveyance. , Common use of the sheet feeding device becomes possible.
Further, since the width of the paper feeding device is set to be narrower than the width of paper that can be passed, it is possible to contribute to downsizing of the mounted image forming apparatus. In addition, since it can be used in common for all paper feed ports of the mounted image forming apparatus, it can contribute to production management and inventory management of the image forming apparatus.
Therefore, a common paper feeding device can be used even if the installation location and the type of paper to be handled are different, and the size can be reduced.

The best mode for carrying out the present invention will be described below in detail with reference to the drawings. FIG. 1 is a perspective view of an essential part of a paper feeding device which is the best mode for carrying out the present invention. As shown in FIG. 1, the paper feeding device 0 sucks air from the four endless belts 4a, 4b, 4c, and 4d for feeding and conveying paper and the belts 4a, 4b, 4c, and 4d. The air suction fan 1 and a duct 2 serving as an air passage from the belts 4a, 4b, 4c, and 4d to the air suction fan 1 are provided.
The belts 4 a, 4 b, 4 c, and 4 d are arranged close to each other along the paper conveyance direction, and each endless belt is stretched by a drive shaft (roller) 9 and a belt holding member 10. Thus, it is rotationally driven along the peripheral surface of the belt holding member 10. The drive shafts 9 of the belts 4a, 4b, 4c and 4d are connected by power transmission means X for driving the belt composed of gears and belts which will be described later. Covers 3a, 3b, 3c, 3d, and 3e covering the power transmission means X are located on the side opposite to the duct 2 arranged on one side of the belt groups 4a to 4d and where the power transmission means X is located. Is attached. Further, pins 5 for fixing the sheet feeding device to an apparatus body such as an image forming apparatus protrude from both side portions (duct portion and cover portion) of some belts, in this example, belts 4c and 4d. ing. The width of the sheet feeding device 0 (the distance from the end of the duct 2 to the ends of the covers 3a to 3e) is set to be narrower than the width of the sheet that can be passed.

FIG. 2 is a cross-sectional view of the paper feeding device as viewed from above (the duct and belt holding member are shown in cross section), and FIG. 3 is a side view of the power transmission means X of the paper feeding device. As shown in FIGS. 1, 2 and 3, the belt driving force of the sheet feeding device 0 is given by a single drive motor 7 provided on the side portion where the belt 4b is disposed. The driving force from the drive motor 7 is transmitted by the gears 6 and the transmission belts 8 constituting the driving force transmission means X, and the transmission belts 8 are driven through the drive shafts 9 fixed to the gears 6. The gear 6 includes a gear 6 a fixed to the drive shaft 9 and a gear 6 b that is rotatably supported by the belt holding member 10. Each drive belt 8 is stretched between pulleys provided coaxially with each gear 6b, and is configured to be able to sequentially transmit drive force to the adjacent belts 4a, 4b, 4c, and 4d. Of course, the configuration of the duct 2 is also continuously connected so that the belts 4a, 4b, 4c, 4d around the shaft 9 can be rotated.
Further, as shown in FIG. 2, the duct 2 is connected across four belt holding members 10 around which the belts are wound, and air is sucked from the loops of the belts through the belts 4a to 4d. It is supposed to be. Therefore, each belt holding member 10 is hollow, the hollow portion has a flow path communicating with the duct 2, and a plurality of suction holes 11 through which the air passes are formed in the lower surface. FIG. 4 is a cross-sectional view around the belt holding member 10. As can be seen from FIG. 4, the suction hole 11 (FIG. 2) is formed only in a part (lower side in the drawing) of the belt holding member 10. This is because the sheet is adsorbed on one belt surface (lower surface side). On the other hand, as shown in FIG. 1, each of the belts 4a to 4d is provided with a plurality of suction holes 4A. As a result, air is sucked from the front surface (lower surface) of each belt, and the paper is adsorbed.
In the sheet feeding device 0 shown here, the belt 4a rotates with respect to the belt 4b, and the belt 4b rotates with respect to the belt 4c to change the angle between the two belts (bent position from a linear posture with respect to each other). Change to relationship). That is, the plurality of belts can be changed to the flat positional relationship shown in FIG. 1 and the bent positional relationship shown in FIG.

FIG. 5 is a top view of the turning force applying means Y as a mechanism for applying turning force to the belts 4a and 4b, and FIG. 6 is a side view of FIG.
The rotational force imparting means Y is a reversible rotation motor (stepping motor) 12a, 12b (a stepping motor) that serves as a drive source for bending the belt holding members 10a to 10d in the vertical direction around the drive shafts 9a to 9c. Motor 12a is fixed to belt holding member 10b, motor 12b is fixed to belt holding member 10c), output gears 107a and 107b integrated with output shafts of drive motors 12a and 12b, and output gears. Positioning gears 101a, 101b, etc., which mesh with 107a, 107b and receive driving force. The positioning gears 101a and 101b are integrated with the belt holding members 10a and 101b, and are arranged coaxially and in a non-contact manner on the outer circumferences of the shafts extending from the drive shafts 9a and 9b. Accordingly, by rotating the output gears 107a and 107b, the driving force is transmitted to the positioning gears 101a and 101b irrespective of the driving shafts 9a and 9b, and the belts are centered on the rotating shafts 9a and 9b. The holding members 10a to 10c (that is, the belts 4a to 4c) can be rotated. That is, the motor 12a determines the posture of the belt holding member 10a with respect to 10b according to the rotation amount of the gear 107a. Further, the motor 21b determines the posture of 10b with respect to the belt holding member 10c according to the rotation amount of the gear 107b.
Next, referring to FIG. 5, the driving system of each belt by the power transmission means X will be described. First, each of the belt holding members 10a and 10b rotatably supports the driven gears 103a and 103b by a cylindrical portion protruding near one end thereof. When the drive motor 7 rotates the drive gear 6a-3 fixed on the same axis as the drive shaft 9c, the drive force is transmitted via the composite gear 104c, the transmission belt 102c, and the composite gear 106d, in which the gear and pulley are combined. While driving the drive gear 6a-4 (drive shaft 9d), from the drive gear 6a-3, the composite gear 106c, the transmission belt 102b, the composite gear 104b, the driven gear 103b, the composite gear 106b ′ (integrated with the gear 106b), The driving force sequentially transmitted through the belt 102a, the composite gear 104a, the driven gear 103a, and the composite gear 106a ′ (integrated with the gear 106a) drives the drive shafts 9a to 9c to rotate. As a result, each belt 4a-4d is rotationally driven.
In FIG. 5, the turning force of the belt 4a is given by the turning motor 12a through the gear 6a, and the turning force of the belt 4b is given by the turning motor 12b through the gear 6b. Thereby, as shown in FIG. 6, the two belts can freely rotate.

FIG. 7 is a side view of the periphery of the paper feeding device when the paper feeding device is attached to the image forming apparatus. The image forming apparatus shown in this example is a composite copying machine having functions such as copying, faxing, printers, and scanners using an electrophotographic system. Details of the image forming apparatus will be described later. As shown in FIG. 7, the paper P for forming an image is stacked on the paper feeding unit of the image forming apparatus. At the time of paper feeding, the uppermost sheet of the sheet bundle is pulled out in the horizontal direction (right side in FIG. 7) and passes above the sheet stacking position through the turn section 14 and the vertical transport section 13 as a transport guide. It is conveyed to the arranged image forming process section.
As shown in FIG. 7, the sheet feeding device is supported in the image forming apparatus by pins 5 above the stacked sheet bundle. At this time, the belts 4c and 4d are attached in a state where the belts 4c and 4d are bent with respect to each other so that portions corresponding to the belts 4c and 4d follow the shape of the guide surface of the turn portion 14. The end of the belt 4d opposite to the belt 4c is in contact with the longitudinal conveyance driven roller 40. The longitudinal conveyance driven roller 40 is urged toward the belt 4d by a spring 41, and is driven as the belt 4d is driven. Accordingly, the belt 4d and the vertical conveyance driven roller 40 convey the paper so as to be pushed upward while sandwiching the paper.
On the other hand, the portions corresponding to the belts 4a and 4b are not fixed as can be seen from the drawing. This is to allow the belts 4a and 4b to freely rotate so as to bend the joints. FIG. 8 is a side view of the periphery of the paper feeding device when the belts 4a and 4b are arranged below the state of FIG. 7 and the belt surface is in close contact with the paper surface. When feeding paper, first, in this state, the sheet is adsorbed to the belts 4a and 4b by the action of the air suction fan 1 (FIG. 1).

9 and 10 are side views of the periphery of the sheet feeding device showing the next step of the sheet feeding operation shown in FIG. After adsorbing the uppermost sheet of the sheet bundle as shown in FIG. 8, the belts 4a and 4b are bent as shown in FIG. 9, and the inclination of the belts 4a and 4b is kept almost as shown in FIG. Make it horizontal. In other words, the second sheet that arrives at the uppermost sheet is separated by the waving operation. This waving operation can be appropriately changed according to the type of paper. For example, the control means (not shown) drives the motors 12a and 12b in accordance with information relating to the difference in paper thickness that has been input in advance and has been set in advance to change the positional relationship between the belts so It is also possible to change. The waving operation may be set so that the sheet separation performance, the cardboard conveyance performance, and the like are sufficiently exhibited. After performing the undulation operation and holding only the uppermost sheet as shown in FIG. 10, the belts 4a to 4d are driven to start conveyance.
As described above, in the paper feeding device shown here, since it is installed only above the paper set for feeding in the paper feeding tray, the space for separating the paper is greatly reduced, and the device In addition to downsizing, it is possible to contribute to downsizing of the mounted image forming apparatus. In addition, because paper is adsorbed by air and separated by undulating action, there is no stress on the surface of the paper, and the effect on the next process (image forming unit) is reduced, enabling good image formation. There is no slip between the two and the paper can be conveyed with high accuracy.
In addition, since the waving operation can be changed according to the type of paper, it is possible to cope with the state of the paper and widen the width of the corresponding paper type. In addition, since a plurality of belts are connected so as to be continuous along the paper conveyance direction, and each belt can be bent with respect to the adjacent belt, it is not affected by the layout of the paper feed separation conveyance unit such as horizontal conveyance and vertical conveyance. , Common use of the sheet feeding device becomes possible.
Further, since the width of the paper feeding device is set to be narrower than the width of the minimum paper that can be passed, it is possible to contribute to miniaturization of the mounted image forming apparatus. In addition, since it can be used in common for all paper feed ports of the mounted image forming apparatus, it can contribute to production management and inventory management of the image forming apparatus.
Therefore, a common paper feeding device can be used even if the installation location and the type of paper to be handled are different, and the size can be reduced.

Here, an image forming apparatus equipped with a sheet feeding device which is the best mode for carrying out the present invention will be described. FIG. 11 shows an image forming apparatus main body provided with the above-described conveyance path. An image forming unit 100 is provided in the image forming apparatus main body 10a. The image forming unit 100 is provided with a drum-shaped image bearing member (photosensitive member) 11c, and a charging device 12c, a developing device 13a, a transfer / conveying device 14a, a cleaning device 15 and the like are disposed around the image forming unit 100. A laser writing device 16 is provided on the image forming unit 100. Although not shown, the laser writing device 16 includes a light source such as a laser diode, a polygonal mirror for scanning, and a polygon motor. A scanning optical system such as an fθ lens and a mirror is provided.
A fixing device 17 is provided on the left side of the cleaning device 15 in the drawing. The fixing device 17 includes a fixing roller 18 incorporating a heater and a pressure roller 19 that presses against the fixing roller 18 from below. In the lower part of the apparatus main body 10a, a duplex unit 22 and a four-stage sheet cassette 23 are provided at the top and bottom. A sheet material such as paper and an OHP sheet is stored in the paper feed cassette 23. The double-sided unit 22 passes through the re-feeding path A, and the feeding cassette 23 passes through the supply path B to the common feeding path C extending downward from the image carrier 11c. The duplex unit 22 is branched from the middle of the sheet discharge path D extending from the outlet of the fixing device 17 to form a reverse path E.
A contact glass 26 is installed in the image reading unit 24 on the upper surface of the apparatus main body 10a. An automatic document feeder 27 is provided on the apparatus main body 10a so as to cover the contact glass 26 so as to be opened and closed. The automatic document feeder 27, the optical reading device 20, and the image reading device 200 are configured. A manual feed tray 28 for guiding the manual sheet material to the paper feed path C is provided on the right side surface of the apparatus main body 10a so as to be freely opened and closed. In addition, a large-volume sheet feeding device 30 is disposed externally to the apparatus main body 10a, and a large amount of sheet materials are stacked therein and stored so as to be movable up and down.
On the other hand, on the left side surface of the apparatus main body 10a, a sheet post-processing device 31 is installed externally to the apparatus main body 10a, accepts the sheet material discharged through the paper discharge path D, and is discharged as it is onto the upper tray 32. Alternatively, after post-processing such as stapling / drilling, the sheet is discharged onto the upper tray 32 or the lower tray 33.

When making a copy using this image forming apparatus, a document is set on the automatic document feeder 27 or the automatic document device 27 is opened and a document is set directly on the contact glass 26. Then, when a start switch (not shown) is pressed and the automatic document feeder 27 is driven to convey the document on the contact glass 26 of the image reading unit 24 or when the document is set on the contact glass 26 in advance, the document is set. A certain original is sent below the image carrier 11 c of the image forming unit 100.
At the same time, the sheet feeding device 0 of the present invention is rotationally driven to feed the sheet material from the corresponding sheet feeding cassette 23 among the plurality of sheet feeding cassettes 23 provided in the apparatus main body 10a. C is carried by the carrying roller 35, and abutted against the registration roller 36 and stopped. Then, the registration roller 36 is rotated in synchronization with the rotation of the image carrier 11c, and is sent to the lower side of the image carrier 11c of the image forming unit 100.
Alternatively, the sheet feeding roller 37 is rotated to feed out the sheet material from the inside of the large volume sheet feeding device 30, put into the sheet feeding path C through the conveying path F, conveyed by the conveying roller 35, and abutted against the registration roller 36 and stopped. Alternatively, the sheet feeding roller 38 in the manual sheet feeding unit is rotated, the manual sheet material set on the opened manual tray 28 is put into the sheet feeding path C, and is also abutted against the registration roller 36. Then, the registration roller 36 is rotated in synchronization with the rotation of the image carrier 11c, and is sent to the lower side of the image carrier 11c of the image forming unit 100.
On the other hand, when a start switch (not shown) is pressed, the image carrier 11c of the image forming unit 100 is simultaneously rotated clockwise in the drawing. Then, along with the rotation of the image carrier 11c, the charging device 12c first charges the surface uniformly, and then the laser writing device 16 irradiates laser light according to the reading content read by the optical reading device 20 described above. Writing is performed to form an electrostatic latent image on the surface of the image carrier 11c, and then toner is attached by the developing device 13a to make the electrostatic latent image visible.
Then, as described above, the visible image is transferred by the transfer / conveyance device 14a to the sheet material fed downward to the image carrier 11c. After the image transfer, the image carrier 11c is cleaned with a cleaning device 15 to remove residual toner and prepare for the next similar image formation.
On the other hand, the sheet material after the image transfer is conveyed by the transfer / conveyance device 14a and put into the fixing device 17, and heat and pressure are applied by the fixing roller 18 and the pressure roller 19 to fix the transferred image. Thereafter, the sheet is discharged to the sheet post-processing device 31 through the sheet discharge path D.
When forming an image on both sides of the sheet material, it is put in the reverse path E from the middle of the paper discharge path D, reversed by the duplex unit 22 and fed again, and separately formed on the back surface of the sheet material by the transfer / conveyance device 14a. After the transferred image on the image carrier 11c is transferred, the transferred image is fixed by the fixing device 17 and discharged to the sheet post-processing device 31.

1 is a perspective view of a paper feeding device that is the best mode for carrying out the invention. FIG. 4 is a cross-sectional view when viewed from the upper surface of the paper feeding device. The side view of the power transmission means of a paper feeder. Sectional drawing of the belt holding member 10 periphery. The top view of the turning force provision means as a mechanism for providing turning force to the belts 4a and 4b. The side view of FIG. FIG. 6 is a side view of the periphery of the paper feeding device when the paper feeding device is attached to the image forming apparatus. FIG. 6 is a side view of the periphery of the paper feeding device when the belt surface is in close contact with the paper surface. FIG. 6 is a side view of the periphery of a paper feeding device showing a undulating operation (part 1). FIG. 6 is a side view of the periphery of a paper feeding device showing a undulating operation (part 2). 1 is a cross-sectional view of an image forming apparatus equipped with a paper feeding device that is the best mode for carrying out the present invention.

Explanation of symbols

  1 Air suction fan, 2 duct, 3a, 3b, 3c, 3d, 3e cover, 4a, 4b, 4c, 4d belt, 5 pin, 6, 11a, 11b gear, 7 drive motor, 8 belt, 9 shaft, 10 belt Holding member, 10a Image forming apparatus main body, 11 Suction hole, 11c Image carrier (photoreceptor), 12a, 12b Rotating motor, 12c Charging device, 13 Vertical transport unit, 13a Developing device, 14 Turn unit, 14a Transfer / transport Device, 15 Cleaning device, 16 Laser writing device, 17 Fixing device, 18 Fixing roller, 19 Pressure roller, 20 Optical reading device, 22 Duplex unit, 23 Paper feed cassette, 24 Image reading unit, 26 Contact glass, 27 Automatic document Conveying device, 28 manual feed tray, 30 mass feeding device, 31 sheet post-processing device, 32 Stage of the tray, 33 lower tray 35 transport rollers, 36 registration rollers, 37, 38 the paper feed roller, 40 a vertical transport driven roller, 41 a spring, 100 imaging unit, 200 image reading apparatus

Claims (9)

In a paper feeding device that separates and transports only the uppermost sheet from a stack of stacked paper by air suction,
A plurality of endless belts that are provided with suction holes for air suction for adsorbing the uppermost paper and that are adjacently arranged in a line along the paper conveyance direction;
Power transmission means for applying a belt driving force to the belt,
The paper feeding device, wherein the paper feeding device is disposed only within an area range of an upper surface of the sheet bundle. The paper feeding device according to claim 1.
The plurality of belts are configured to be changeable to a flat positional relationship and a bent positional relationship with each other, and when the sheet is sucked and conveyed, each belt undulates to separate the adsorbed sheet from other sheets. A paper feeder characterized by that. The sheet feeding device according to claim 1 or 2,
A paper feeding device comprising control means for changing the undulating operation according to the type of paper. In the paper feeding device that separates and conveys only one sheet from the stacked paper bundle by air suction,
A plurality of endless belts having suction holes for air suction for adsorbing paper; and
Power transmission means for applying a belt driving force to each belt;
A turning force applying means for rotating the belt with respect to the other belt,
A plurality of the belts are connected so as to be continuous along the paper conveyance direction so that the direction of the conveyance path formed by the belts can be freely set.
A sheet feeding device, wherein the sheet feeding apparatus is disposed only within a range of an area of an upper surface of sheets stacked for sheet feeding. The sheet feeding device according to claim 4, wherein
A paper feeding device configured so that a width of the paper feeding device falls within a range of a width of a minimum size paper.   6. The sheet feeding device according to claim 4, wherein the sheet feeding device has a configuration that can be used in common for all the sheet feeding ports of the mounted image forming apparatus. The sheet feeding device according to claim 4, 5 or 6,
Each of the belts separates the adsorbed paper and the other paper by performing a wave motion when sucking and conveying the paper. The sheet feeding device according to claim 4, 5, 6, or 7,
A paper feeding device comprising control means for changing the undulating operation according to the type of paper.   An image forming apparatus comprising the paper feeding device according to claim 1.

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