JP2008105790A - Sheet feeding device and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet feeding device capable of elevating a middle plate without enlarging the device, and an image forming device. <P>SOLUTION: Through a driven member 38, the other driven member 36 is revolved in the vertical direction by a cam 30 rotating together with a sheet feeding roller 3, and the middle plate 50 is revolved to a stand-by position separated from the sheet feeding roller 3 against an energizing member 37 or stacked sheets are revolved to a feeding position to make pressure-contact with the sheet feeding roller 3 by the energizing member 37. It is possible to revolve the middle plate 50 in the vertical direction without enlarging the cam 30 in diameter by making the cam 30 contact with the driven member 38 between a revolving fulcrum 38c of the driven member 38 and an abutting part of a revolving end 38a of the driven member 38 and the other driven member 36. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a sheet feeding apparatus and an image forming apparatus, and more particularly to a configuration for moving an intermediate plate provided rotatably in a sheet storage portion between a standby position and a feeding position.

  2. Description of the Related Art Conventionally, an image forming apparatus such as a printer, a facsimile machine, or a copier has a sheet feeding device that feeds a sheet stored in a sheet feeding cassette toward an image forming unit by a sheet feeding roller when forming an image. There is something.

  FIG. 8 shows the configuration of such a conventional sheet feeding apparatus. In FIG. 8, reference numeral 1 denotes a paper feed cassette. Here, the sheet feeding cassette 1 is detachably attached to an apparatus main body (not shown). When setting the sheet S, the sheet S is set after being pulled out from the apparatus main body in the direction of arrow A.

  Reference numeral 3 denotes a sheet feeding roller that is provided in the apparatus main body and feeds the sheet S by frictional force. The sheet feeding roller 3 has a part of its peripheral surface cut out and is rotated counterclockwise only during feeding. It is controlled to rotate once. Reference numeral 50 denotes an intermediate plate which is provided in the sheet feeding cassette 1 so as to be pivotable in the vertical direction. The intermediate plate 50 is attached to the sheet feeding roller 3 with a predetermined pressure by a spring 151. It is energized.

  Reference numeral 2 denotes a separation pad that comes into pressure contact with the sheet feeding roller 3 during sheet feeding. The separation pad 2 is rotatably supported by the sheet feeding cassette 1 and is fed with a predetermined pressure by a spring 20. It is affixed to a holder 2 a that is biased toward the feed roller 3. A sheet feeding roller 30 is disposed so as to be rotatable coaxially with the sheet feeding roller 3. The sheet feeding roller 30 has a notch 3 a shown in FIG. The sheet S and the separation pad 2 are in contact with each other when stopped at the standby position.

  In the sheet feeding apparatus having such a configuration, when the sheet feeding roller 3 rotates during image formation, the sheet S is directed toward the nip portion with the separation pad 2 by the frictional force between the sheet feeding roller 3 and the sheet S. Sent.

  At this time, a plurality of sheets S may be fed toward the nip portion due to the frictional force between the sheets. In this case, the second and subsequent sheets S are stopped by the separation pad 2 having a higher coefficient of friction than the sheet S at the nip portion between the sheet feeding roller 3 and the separation pad 2.

  As a result, only the uppermost sheet S1, which is in contact with the sheet feeding roller 3 having a higher friction coefficient than the separation pad 2 and is given a strong conveying force, is sent to the conveying roller 4, and thereafter The sheet S is conveyed to an image forming unit (not shown) by the conveyance roller 4. After the sheet S is sent to the conveying roller 4 as described above, the sheet feeding roller 3 stops at a standby position where the notch 3a faces the uppermost sheet S1, as shown in FIG.

  By the way, in such a sheet feeding device, the intermediate plate 50 is urged to press the sheet S on the intermediate plate against the sheet feeding roller 3, but in this case, the sheet conveyed to the image forming unit. Is affected by the back tension generated between the intermediate plate 50 and the sheet feeding roller 3.

  Therefore, in order to avoid the influence of such back tension, conventionally, for example, an intermediate plate moving mechanism is provided, and after the sheet is fed by the intermediate plate moving mechanism, the intermediate plate is moved downward. I have to. As such an intermediate plate moving mechanism, as shown in FIG. 9, first and second levers 51 and 52 that are swingable, an eccentric cam 53 that swings the first and second levers 51 and 52, and an eccentric cam. 53 includes a clutch mechanism 54 that relays driving force (see Patent Document 1).

  In such an intermediate plate moving mechanism, the eccentric cam 53 is rotated by the clutch mechanism 54 with the rotation of the sheet feeding roller, and the first and second levers 51 and 52 are interlocked by the rotation of the eccentric cam 53, respectively. And are swung in the opposite direction. The first and second levers 51 and 52 thus swing in the opposite directions, respectively, so that the intermediate plate 50 can be rotated in the vertical direction.

JP 2006-103972 A

  By the way, in the conventional sheet feeding apparatus provided with such an intermediate plate moving mechanism, the swing centers 51 a and 52 a of the first and second levers 51 and 52 are the contact portions of the eccentric cam 53 and the second lever 52. 55 and the rotation center 50a of the intermediate plate 50. And when the eccentric cam 53 is arranged in this way, it is necessary to increase the diameter of the eccentric cam 53 in accordance with the range of raising and lowering of the intermediate plate 50 to be set. Increase in size.

  Accordingly, the present invention has been made in view of such a situation, and an object thereof is to provide a sheet feeding apparatus and an image forming apparatus that can raise and lower an intermediate plate without increasing the size of the apparatus. To do.

  The present invention includes a sheet storage unit that is detachably attached to the apparatus main body and rotatably provided with a middle plate on which sheets are stacked, a sheet feeding roller that feeds sheets stacked on the middle plate, A biasing member for biasing the intermediate plate toward the sheet feeding roller; a cam that rotates together with the sheet feeding roller; abutting the cam; By rotating in the vertical direction by rotation, the intermediate plate is separated from the sheet feeding roller against the urging member, and the urging member feeds the stacked sheets to the sheet. A driven member for rotating between a feeding position to be brought into pressure contact with the roller, and the cam between a rotation fulcrum of the driven member and an engagement position of the driven member with the intermediate plate The contact member is brought into contact with the driven member. It is intended.

  As in the present invention, by bringing the cam into contact with the driven member between the rotation fulcrum of the driven member and the position where the driven member is engaged with the intermediate plate, the intermediate plate can be removed without increasing the size of the device. Can be moved up and down.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the best embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a diagram showing a schematic configuration of a laser beam printer which is an example of an image forming apparatus provided with a sheet feeding apparatus according to an embodiment of the present invention.

  In FIG. 1, reference numeral 100 denotes a laser beam printer. The laser beam printer 100 includes an image forming unit 101 that forms an image, a sheet feeding device 102 that separates and feeds sheets S one by one to the image forming unit 101, and the like. It has.

  The image forming unit 101 includes a process cartridge 70 that can be attached to and detached from a laser beam printer main body (hereinafter referred to as an apparatus main body) 100A, a transfer roller 6, and the like. The process cartridge 70 includes a photosensitive drum 7, a charging roller 9, a developing unit 10, a cleaning unit (not shown), and the like.

  The sheet feeding device 102 is provided above the sheet feeding cassette 1 and the sheet feeding cassette 1 which are sheet storing units for storing sheets, and a part of the peripheral surface for feeding the sheet S stored in the sheet feeding cassette 1 is provided. A sheet feeding roller 3 having a substantially half-moon shape cut out is provided.

  The sheet feeding cassette 1 stacks the sheet S with the cassette main body 1a and is held by the cassette main body 1a so as to be rotatable in the vertical direction about the shaft 50b as a fulcrum. An intermediate plate 50 urged toward the roller 3 is provided. When forming an image, the intermediate plate 50 is raised by a spring 51 to a sheet feedable position where the sheet S is pressed against the sheet feed roller 3 with a predetermined pressure.

  In addition, the sheet feeding cassette 1 is held by a rotatable pad holder 20 that is pressed toward the sheet feeding roller by a spring (not shown), and a sheet bundle is wound with the intermediate plate 50, and the sheet feeding roller A separation pad 2 for separating the sheets S fed by 3 one by one is provided. A sheet feeding roller provided coaxially with the sheet feeding roller 3 and always in contact with the separation pad 2 is disposed on both ends of the sheet feeding roller 3. The sheet S is prevented from being carried along.

  In FIG. 1, 22 is a laser scanner unit, 15 is a fixing device, and 18 and 19 are a pair of discharge rollers for discharging the sheet S to a discharge tray 21.

  Next, an image forming operation of the laser beam printer 100 configured as described above will be described.

  When image information is sent from a personal computer (not shown) or the like, and a control unit (not shown) that performs image formation processing on this image information issues a print signal, the sheet feeding roller 3 rotates. In conjunction with this, the middle plate 50 urged toward the sheet feeding roller by the force of the coil spring 51 is rotated upward about the shaft 50b by the middle plate moving mechanism, which will be described later. 1 is pressed against the sheet feeding roller 3 with a predetermined force.

  Here, the sheet feeding roller 3 is controlled to rotate counterclockwise only at the time of paper feeding. By rotating in this way, the sheet feeding roller 3 feeds the pressed sheet S by frictional force. To send. When a plurality of sheets S on the intermediate plate are sent out simultaneously, only the uppermost sheet is separated by the action of the separation pad 2 and conveyed downstream.

  Next, after the uppermost sheet separated by the separation pad 2 is conveyed by the conveying roller pair 4, the skew correction is performed by the registration unit 5, and thereafter, the registration unit 5 and the photosensitive drum 7 are transferred. It is fed into the nip portion with the roller 6.

  On the other hand, laser light from the laser scanner unit 22 is uniformly charged in advance by the charging roller 9 based on the image information together with this print command, and is irradiated onto the photosensitive drum rotating clockwise. Thereby, an electrostatic latent image is formed on the surface of the photosensitive drum 7. Further, the latent image is developed by the developing device 10 to form a toner image on the photosensitive drum.

  The toner image thus formed on the photosensitive drum is then transferred to the sheet S sent to the nip portion between the photosensitive drum 7 and the transfer roller 6 by the resist unit 5.

  Further, the sheet S on which the toner image is transferred is sent to the fixing device 15, and is guided to the nip portion between the heating unit 13 of the fixing device 15 and the pressure roller 14 in pressure contact therewith, and passes through the nip portion. The toner image transferred to the sheet surface is heated and pressurized and fixed on the sheet surface. Thereafter, the sheet that has passed through the fixing device 15 is conveyed by a pair of discharge rollers 18 and 19 and discharged onto the discharge tray 21.

  FIG. 2 is a side view of the paper feed cassette 1, and in FIG. 2, reference numeral 11 denotes a side plate constituting the side wall surface of the cassette body 1 a of the paper feed cassette 1. Reference numeral 50a denotes a protruding portion projecting in the width direction from both ends of the front end portion of the sheet feeding direction of the intermediate plate 50. The protruding portion 50a is formed from both side surfaces of the cassette from the opening portion 11a provided in the side plate 11. It protrudes outward. When the middle plate 50 is rotated in the vertical direction, the middle plate 50 is rotated about the shaft 50b as a rotation fulcrum while being guided by the opening portion 11a and the protruding portion 50a.

  Here, in the present embodiment, when the sheet is fed, the intermediate plate 50 is moved to the sheet feedable position by the intermediate plate moving mechanism.

  Next, an intermediate plate moving mechanism for moving the intermediate plate 50 will be described. FIG. 3 shows a state where the intermediate plate is rotated downward and moved to the feeding standby position.

  In FIG. 3, reference numeral 40 denotes an intermediate plate moving mechanism. The intermediate plate moving mechanism 40 includes a cam 30 that is rotatably provided on a roller shaft 31 on which the sheet feeding roller 3 is provided. Further, a spring clutch 32 that is wound around the roller shaft 31 and transmits or blocks the rotational force from the roller shaft 31 to the cam 30, and a lock member 33 that locks the spring clutch 32 is provided on the roller shaft 31. Yes.

  Furthermore, an actuator 34 that engages with a claw portion 33 a provided on the outer peripheral portion of the lock member 33, and a solenoid 35 that engages and disengages the actuator 34 with the claw portion 33 a of the lock member 33 are provided. The spring clutch 32, the lock member 33, and the solenoid 35 constitute a one-way clutch.

  Here, the sheet feeding roller 3 is continuously driven during feeding by a roller shaft 31 that receives a rotational driving force from a drive motor (not shown) via a gear train, and the cam 30 is driven by a spring clutch 32 with respect to the roller shaft 31. Rotate only when driving force is transmitted.

  The spring clutch 32 is tightened with respect to the roller shaft 31 when the solenoid 35 is on and the actuator 34 is attracted as shown in FIG. 4 and is not engaged with the claw portion 33a of the lock member 33. It comes to become. The spring clutch 32 is in a driving force transmission state in which the rotational driving force of the roller shaft 31 is transmitted to the cam 30 in this state.

  The spring clutch 32 is wound so as to be loose with respect to the roller shaft 31 when the solenoid 35 is off and the actuator 34 is engaged with the claw portion 33a of the lock member 33 as shown in FIG. In this state, the driving force is cut off.

  In FIG. 3, reference numeral 36 denotes another driven member that is rotatably provided on the apparatus main body 100 </ b> A with the rotation shaft 36 a serving as a rotation fulcrum, and the other driven member 36 has a protrusion of the intermediate plate 50. The part 50a is provided with a guide groove 36b that is slidably fitted. The other driven member 36 is biased so as to rotate upward by a spring 37 that is a biasing member.

  Reference numeral 38 denotes a driven member that is rotatably provided on the apparatus main body 100A with the rotation shaft 38c as a rotation fulcrum. The driven member 38 has a rotating end (end opposite to the rotating fulcrum) 38a provided on a rotating end (end opposite to the rotating fulcrum) 36c of the other driven member 36. The center portion 38 b is in contact with the cam surface 39 of the cam 30. Thus, the driven member 38 and the intermediate plate 50 are indirectly engaged with each other through the other driven member 36, and the intermediate plate 50 is rotated in the vertical direction by the rotation of the cam 30.

  When the driven member 38 is rotated downward by bringing the rotating end 38a of the driven member 38 into contact with the rotating end 36c (contact portion) of the other driven member 36 in this manner, the other driven member 36 rotates downward against the spring 37. When the driven member 38 is rotated upward, the other driven member 36 is rotated upward together with the driven member 38 by the spring 37.

  By the way, when the intermediate plate 50 is in the feeding standby position shown in FIG. 3, the spring clutch 32 is in the driving force cut-off state, and at this time, the cam 30 has the long diameter portion 39 a of the cam surface 39 at the center portion of the driven member 38. It stops at the position where 38b is pressed. When the cam 30 stops at such a position, the driven member 38 rotates downward about the rotating shaft 38c, and accordingly, the rotating end 36c of the other driven member 36 is pressed downward, The driven member 36 is in a state of rotating downward about the rotation shaft 36a.

  When the other driven member 36 rotates downward in this way, the protruding portion 50a loosely fitted in the guide groove 36b of the other driven member 36 is pressed, and the intermediate plate 50 also rotates downward with the shaft 50b as a fulcrum. It stops at the feeding standby position.

  When the paper feeding operation is started, the roller shaft 31 rotates and the solenoid 35 is turned on to draw the actuator 34. As a result, the engagement of the lock member 33 with the claw portion 33 a is released, the spring clutch 32 enters the driving force transmission state, and the cam 30 rotates with the roller shaft 31. When the cam 30 rotates in this way, as shown in FIG. 4, the pressing on the central portion 38 b of the driven member 38 by the long diameter portion 39 a of the cam surface 39 of the cam 30 is released.

  Thereafter, when the cam 30 further rotates, the short diameter portion 39b of the cam surface 39 comes into contact with the central portion 38b of the driven member 38, and the driven member 38 is counteracted by the urging force of the spring 37. Rotate clockwise (upward). Further, as the driven member 38 rotates counterclockwise, the other driven member 36 biased by the spring 37 also rotates clockwise (upward).

  When the other driven member 36 rotates in the clockwise direction in this way, the intermediate plate 50 in which the protruding portion 50a is loosely fitted in the guide groove 36b of the other driven member 36 also rotates upward with the shaft 50b as a fulcrum. The moving end portion 50c moves in the direction of the sheet feeding roller (upward). When the rotating end 50c of the intermediate plate 50 moves upward as described above, the sheet feeding roller 3 rotates together with the roller shaft 31, and thus comes into contact with the sheet on the intermediate plate 50 and starts from the uppermost sheet. The paper is sequentially fed to the nip with the separation pad.

  Here, at the nip portion between the sheet feeding roller 30 and the separation pad 2, the frictional force between the sheets is smaller than the frictional force between the sheet feeding roller 30 and the separation pad 2 and the sheet S as described above. Is set to For this reason, even when double feeding occurs due to sheet feeding by the sheet feeding roller 30, only the sheet S that is in contact with the sheet feeding roller 30 is separated and fed.

  Next, when such a separation operation is completed, the diameter of the cam surface 39 in the rotating cam 30 gradually increases, so that the center portion 38b of the driven member 38 is pressed by the cam surface 39 and rotates downward. When the driven member 38 rotates downward as described above, the driven member 38 rotates the other driven member 36 downward, and accordingly, the rotating end 50 c of the intermediate plate 50 is separated from the lower side of the sheet feeding roller 3. 4 moves from the feeding position shown in FIG. 4 to the feeding standby position shown in FIG.

  That is, when the sheet feeding operation is started by the middle plate moving mechanism 40, the middle plate 50 moves from the feeding standby position shown in FIG. 3 to the feeding position shown in FIG. 4, and the uppermost sheet is fed. When the process is completed, the printer moves to the feeding standby position shown in FIG.

  Thereafter, when the sheet feeding operation for the next sheet S is started, the middle plate 50 is lifted by the middle plate moving mechanism 40 with the rotation end 50c receiving the urging force of the spring 37 in the same manner as described above. Then, the same operation is performed.

  When the sheet feeding cassette 1 is pulled out for sheet supply or the like, the intermediate plate 50 is pulled out while the intermediate plate protrusion 50a is guided along the guide groove 36b, and rotates downward about the shaft 50b. .

  When the paper cassette 1 is mounted in the apparatus main body, when the paper cassette 1 is first pushed in, the middle plate protrusion 50a enters the guide groove 36b, and then the middle plate 50 is moved to another driven member 36. 3 to the position shown in FIG. Thereby, the intermediate plate 50 can be moved to a position corresponding to the phase of the cam 30 without performing the initialization operation of the intermediate plate moving mechanism 40 regardless of the phase of the cam 30.

  Further, since the vertical relationship between the driven member 38 and the other driven member 36 does not change regardless of the phase of the cam 30, the intermediate plate 50 is not shown for the other driven member 36 when the paper feeding cassette 1 is attached or detached. The intermediate plate protrusion 50a comes into contact with the inclined surface of the shaft and rotates about the shaft 50b while being guided. Thereby, the vertical relationship between the driven member 38 and the middle plate 50 does not change.

  By the way, in this embodiment, as shown in FIGS. 3 and 4, the cam 30 is a driven member between the rotating fulcrum 38 c of the driven member 38 and the other contact member 36 of the driven member 38. 38.

  Then, by bringing the cam 30 into contact with the driven member 38 at such a position, the raising / lowering amount of the intermediate plate 50 can be set large without increasing the diameter of the cam 30. As a result, the intermediate plate 50 can be raised and lowered without increasing the size of the apparatus so as not to be affected by the back tension.

  In addition, the position (amount) at which the intermediate plate 50 is pushed down includes the distance between the central portion 38b of the driven member 38 and the rotating shaft 38c, the rotating end 38a of the driven member 38, as well as the diameter of the cam 30. The distance between the center portion 38b and the central portion 38b pressed by the cam 30 is determined. That is, the cam 30 is moved according to the position of the rotation shaft 38 c that is the rotation center of the driven member 38, the rotation end 38 a that is a contact portion with the other driven member 36, and the center portion 38 b that is the pressing portion of the cam 30. The raising / lowering amount of the intermediate plate 50 can be set without increasing the diameter.

  In the description so far, the configuration in which the spring 37 is provided in the apparatus main body 100A has been described. However, the present invention is not limited to this, and for example, as shown in FIG. The urging force may be applied to the intermediate plate 50.

  In addition, as shown in FIG. 6, a roller 60 for reducing sliding resistance may be provided at the rotation end 36c of another driven member 36 that is in contact with the driven member 38. A roller 60 may be provided at the rotation end 36 a of the driven member 38.

  In FIG. 6, reference numeral 70 denotes a sheet presence / absence detecting means for detecting the presence / absence of a sheet on the intermediate plate. The sheet presence / absence detecting means 70 detects a flag 38d provided at the side end of the driven member 38 that rotates counterclockwise as the middle plate 50 that rotates upwards when the number of stacked sheets decreases. By doing so, the presence or absence of a sheet on the intermediate plate is detected.

  Further, in the above description, the case where the intermediate plate 50 is rotated to the standby position or the feeding position against the spring 37 through the driven member 38 and the other driven member 36 by the rotation of the cam 30 has been described. It was. However, the present invention is not limited to this.

  For example, as shown in FIG. 7, the protrusion 50a of the intermediate plate 50 is brought into direct contact with the rotation end of the driven member 38, and the cam 30 is connected to the rotation fulcrum 38c of the driven member 38 and the protrusion 50a of the intermediate plate 50. Between them and the driven member 38. That is, in the above-described embodiment, the driven member 38 and the intermediate plate 50 are indirectly engaged through the other driven member 36, but the driven member 38 and the intermediate plate 50 may be directly engaged. Good. Thereby, like the above-described embodiment, the intermediate plate 50 can be rotated in the vertical direction without increasing the diameter of the cam 30.

1 is a diagram illustrating a schematic configuration of a laser beam printer which is an example of an image forming apparatus including a sheet feeding device according to an embodiment of the present invention. FIG. 4 is a diagram illustrating a configuration of a sheet feeding cassette provided in the sheet feeding apparatus. The block diagram which shows the intermediate | middle board moving mechanism provided in the said sheet | seat feeding apparatus. The figure explaining the intersection of the said intermediate board moving mechanism. The 1st figure which shows the other structure of the said intermediate | middle board moving mechanism. The 2nd figure which shows the other structure of the said intermediate | middle board moving mechanism. The 3rd figure which shows the other structure of the said intermediate | middle board moving mechanism. The figure explaining the structure of the conventional sheet feeding apparatus. The figure explaining the structure of the conventional intermediate plate moving mechanism.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sheet cassette 1a Cassette main body 3 Sheet feed roller 30 Cam 31 Roller shaft 32 Spring clutch 33 Lock member 35 Solenoid 36 Other driven member 36a Rotating shaft 36b Guide groove 36c Rotating end 37 Spring 38 Driven member 38a Rotating end 38b Central portion 38c Rotating shaft 39 Cam surface 40 Middle plate moving mechanism 50 Middle plate 50a Projecting portion 50b Shaft 50c Rotating end 100 Laser beam printer 100A Device main body 101 Image forming portion 102 Sheet feeding device S Sheet

Claims (10)

A sheet storage unit that is detachably attached to the apparatus main body and rotatably provided with a middle plate for stacking sheets, a sheet feeding roller that feeds the sheets stacked on the middle plate, and the middle plate A biasing member for biasing toward the sheet feeding roller;
A cam that rotates together with the sheet feeding roller;
The intermediate plate is separated from the sheet feeding roller against the urging member by contacting the cam and rotating in the vertical direction by the rotation of the cam, and the urging member. A driven member for rotating between a feeding position where the stacked sheets are pressed against the sheet feeding roller, and
The sheet feeding device according to claim 1, wherein the cam is brought into contact with the driven member between a rotation fulcrum of the driven member and an engagement position of the driven member with the intermediate plate.   Provided between the driven member and the intermediate plate is another driven member that contacts the rotating end of the driven member and can be rotated in the vertical direction along with the vertical rotation of the driven member, The biasing member is provided on another driven member and engaged with the intermediate plate, whereby the intermediate plate is moved between the standby position and the feeding position by rotation of the cam. The sheet feeding apparatus according to claim 1.   2. The sheet feeding apparatus according to claim 1, further comprising a clutch mechanism that selectively transmits a driving force for driving the sheet feeding roller to the cam between the sheet feeding roller and the cam. .   3. The sheet feeding apparatus according to claim 2, wherein the clutch mechanism includes a spring clutch and a solenoid device.   The shape of the cam is such that when the sheet is fed through the driven member and the other driven member, the middle plate is moved to the feeding position, and after the sheet feeding, the middle plate is moved to the standby position. The sheet feeding apparatus according to any one of claims 1 to 3, wherein the sheet feeding apparatus is configured as described above.   6. When the sheet storage portion is attached to the apparatus main body, the intermediate plate is guided by the other driven member and moves to a standby position corresponding to the phase of the cam. The sheet feeding apparatus according to any one of the above.   The sheet feeding pressure is generated between the sheet feeding roller and the sheet stacked on the intermediate plate by the urging force of the urging member. The sheet feeding apparatus according to the description.   The roller is provided in one side of the contact part with the rotation end of the said driven member and the rotation end of the said following member of the said other driven member, The one of Claim 1 thru | or 7 characterized by the above-mentioned. Sheet feeding device.   9. The sheet presence / absence detecting means for detecting the presence / absence of a sheet on an intermediate plate according to a rotation position of the driven member or the other driven member. Sheet feeding device.   An image forming apparatus comprising: an image forming unit; and the sheet feeding device according to claim 1 for feeding a sheet to the image forming unit.

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