JP5909440B2 - Sheet conveying apparatus and image forming apparatus provided with the same - Google Patents

Description

  The present invention relates to a sheet conveying apparatus that conveys a sheet and is suitable for application to an image forming apparatus such as a copying machine or a printer.

  A sheet conveying apparatus that conveys a sheet from a tray that accommodates a plurality of sheets is preferably used in an image forming apparatus such as a copier, a printer, a facsimile, or a multifunction machine having these functions. In the image forming apparatus, the sheet conveying apparatus takes out the sheets one by one from the sheet storage section of the tray and conveys them, and an image is formed on the conveyed sheets in the apparatus main body of the image forming apparatus.

  In such a sheet conveying apparatus, the sheet conveying apparatus includes a pickup roller, a sheet feeding roller, and a separation roller. The pickup roller abuts on the uppermost sheet among the sheets stacked in the sheet storage unit, and sends the sheet in the sheet conveyance direction. The paper feed roller and the separation roller form a paper feed nip portion downstream of the pickup roller in the sheet conveyance direction. In the sheet feeding nip portion, the sheets are conveyed one by one in the sheet conveying direction. Patent Document 1 discloses a technique for releasing the nip between a paper feed roller and a separation roller in conjunction with the attachment / detachment of a tray to / from the apparatus main body.

JP 2002-205832 A

  In the sheet conveying apparatus as described in Patent Document 1, a strong pressing force is required to release the pressing of the separation roller against the sheet feeding roller. As a result, the pressing force is applied to the tray, and it may be difficult to attach or detach the tray to or from the apparatus main body.

  The present invention has been made to solve the above-described problem, and includes a sheet conveying device that releases the nip pressure of the paper feeding nip portion in conjunction with the removal of the tray from the apparatus main body, and the same. An object of the image forming apparatus is to suppress an increase in the operating force required to remove the tray as the nip pressure is released.

A sheet conveying apparatus according to an aspect of the present invention is a sheet and a sheet that is detachable from the casing, and a plurality of sheets are stacked therein and mounted in the first direction with respect to the casing. A tray, a sheet conveyance path disposed in the housing and extending from the sheet tray in a second direction intersecting the first direction, and disposed opposite to the sheets stacked on the sheet tray, Rotation driven, sending means for sending out the sheet to the sheet conveying path, and rotatably supported by the housing, abutting on the sheet sent out by the sending means, and driven to rotate, the sheet being conveyed to the sheet conveying path of the paper feed roller for feeding in the second direction downstream side, it is opposed to the paper feed roller, the paper feeding nip formed between the paper feed roller, sheets and other being the sheet of paper Sheet and minute A retard roller which, in a first state in which the sheet tray is attached to the housing, a first positioning means for positioning a first position abutting said retard roller to said feeding roller, the sheet tray in the second state said desorbed from the housing, and a second positioning means for positioning said retard roller to a second position spaced apart from the paper feed roller, a fulcrum portion that extends in said first direction And a support unit that is supported by the housing so as to be rotatable around the fulcrum and supports the retard roller so as to be rotatable. The first positioning means extends in the second direction. A shaft portion; a first abutted portion extending downstream from the first shaft portion in the first direction and contacting the sheet tray; and an upstream side in the first direction from the first shaft portion. Extended A first abutting portion that abuts on the support unit and urges the support unit in a third direction in which the retard roller abuts on the paper feed roller, and is rotatable around the first shaft portion. A first urging member for urging the first movable member around the first shaft portion in a direction in which the first abutting portion urges the support unit; Further, in conjunction with the removal of the sheet tray from the housing, the retard roller is released from the first position by its own weight, and the second position of the retard roller is released from the first position by its own weight. In the first state, the support unit is urged toward the third direction, and in the second state, the second positioning means moves the support unit to the support unit. With Is restricted energized, the second positioning means in conjunction with said sheet tray is detached from the housing, to lock the retard roller that has moved to the second position, in said first state The biasing of the support unit by the first positioning means is allowed, and in the second state, the biasing of the support unit by the first positioning means is restricted, and the support unit is The sheet tray is locked to the second position of the retard roller, and the sheet tray includes a contact member that extends in the first direction and is capable of contacting the first contacted portion. The first contact portion includes an opening portion that is partially opened in the first direction and into which the first contacted portion can be immersed, and the contact member is moved in accordance with the change from the first state to the second state. Before the first movable member By abutting on the first abutted portion, the first movable member is rotated around the first shaft portion against the urging force of the first urging means, and the first abutting portion is The retard roller is spaced apart from the support unit, and the retard roller is disposed at the second position by its own weight including the support unit, and the first contacted portion changes in accordance with the change from the second state to the first state. And the first movable member is rotated around the first shaft portion by the urging force of the first urging means, and the first abutting portion is supported by the supporting member. The retard roller is disposed at the first position by contacting the unit .

According to this configuration, the first positioning unit positions the retard roller at the first position in contact with the paper feed roller in the first state in which the sheet tray is mounted on the housing. The second positioning means positions the retard roller at a second position separated from the paper feed roller in the second state in which the sheet tray is detached from the housing. Therefore, the positioning of the first position and the second position of the retard roller is realized by different means. When the sheet tray is detached from the housing, the first positioning unit releases the positioning of the retard roller in conjunction with the removal of the sheet tray. Thereafter, the retard roller is moved from the first position to the second position by its own weight. Further, the second positioning means locks the retard roller at the second position in conjunction with the removal of the sheet tray. For this reason, the moving force for separating the retard roller from the paper feed roller is not required. For this reason, compared with the case where the retard roller is directly separated from the paper feed roller by the operation force of the sheet tray, the increase of the operation force is suppressed. Further, the retard roller can be stably locked at the second position in conjunction with the detaching operation of the sheet tray. As a result, it is possible to prevent the retard roller from unnecessarily coming into contact with the paper feed roller in a state where the sheet tray is detached from the housing. Further, when the sheet tray is detached from the housing, the sheet feeding nip portion between the sheet feeding roller and the retard roller is released, so that the sheet can be removed even if the sheet is sandwiched in the sheet feeding nip portion. It can be detached from the paper feed nip. According to this configuration, in the first state, the first positioning unit biases the support unit toward the third direction in which the retard roller contacts the paper feed roller. Further, in the second state, the first positioning means is restricted from being biased to the support unit by the second positioning means. The second positioning unit allows the support unit to be biased by the first positioning unit in the first state. Further, in the second state, the second positioning means locks the support unit at the second position of the retard roller in a state where the urging of the support unit by the first positioning means is restricted. For this reason, the retard roller can be disposed at the first position and the second position only by the first positioning means having a function of urging the support unit in the third direction. According to this configuration, the function of the first positioning means is realized by the first movable member including the first shaft portion, the first abutted portion, and the first abutting portion, and the first urging means. Is done. Furthermore, according to this configuration, the support unit can be moved by the first positioning means in conjunction with the operation of attaching and detaching the sheet tray. In particular, when the first contacted part is immersed in the opening formed in the contact member, the rotation restriction of the first movable member is released, and the retard roller is moved from the second position to the first position. The

In the above configuration, the second positioning means unlocks the retard roller disposed at the second position in conjunction with the operation of mounting the sheet tray on the housing, and Preferably, the positioning means moves the retard roller , which has been unlocked, from the second position to the first position in conjunction with the operation of mounting the sheet tray on the housing.

According to this configuration, even when the retard roller is locked at the second position, the retard roller is moved from the second position to the first position in conjunction with the operation of mounting the sheet tray on the housing. be able to.

  In the above configuration, the second positioning means extends in one direction from the second shaft portion and the second shaft portion, and is positioned at the second position at a third position around the second shaft portion. A second abutting portion that locks the support unit disposed; and a second direction extending from the second shaft portion in a direction different from the second abutting portion, the first direction being greater than the first abutted portion. A second abutting portion that abuts against the abutting member on the downstream side, and a second movable member that is rotatable about the second shaft portion, and the second abutting portion is the third abutting portion. And a second urging means for urging the second movable member around the second shaft portion so that the second movable member is arranged at the position.

  According to this structure, the function of the said 2nd positioning means is implement | achieved by the 2nd movable member which consists of a 2nd axial part, a 2nd to-be-contacted part, a 2nd contact part, and a 2nd biasing means. .

  In the above configuration, the second movable member is moved into the second state by the contact member coming into contact with the second contacted portion in accordance with the change from the second state to the first state. It is rotated around the second shaft part against the urging force of the urging means, the support unit is unlocked by the second contact part, and the first state is changed to the second state. With the change, the contact member is separated from the second contacted portion, so that the second movable member is rotated around the second shaft portion by the biasing force of the second biasing means. Preferably, the second contact portion is disposed at the third position, and the support unit is locked at the second position of the retard roller.

  According to this configuration, the retard roller can be locked and unlocked via the support unit by the second positioning means in conjunction with the operation of attaching and detaching the sheet tray.

  An image forming apparatus according to another aspect of the present invention includes any of the above sheet conveying apparatuses and an image forming unit that forms an image on the sheet conveyed by the sheet conveying apparatus. And

According to this configuration, a moving force for separating the retard roller from the paper feed roller is not required. For this reason, compared with the case where the retard roller is moved directly from the paper feed roller by the operation force of the sheet tray, the increase of the operation force is suppressed. Further, the retard roller can be stably locked at the second position in conjunction with the detaching operation of the sheet tray. As a result, it is possible to prevent the retard roller from unnecessarily coming into contact with the paper feed roller in a state where the sheet tray is detached from the housing. Further, when the sheet tray is detached from the housing, the sheet feeding nip portion between the sheet feeding roller and the retard roller is released, so that the sheet can be removed even if the sheet is sandwiched in the sheet feeding nip portion. It can be detached from the paper feed nip. As a result, sheet clogging hardly occurs inside the housing, and an image is stably formed on the sheet in the image forming unit.

  According to the present invention, in a sheet conveying apparatus that releases the nip pressure of the sheet feeding nip portion in conjunction with the removal of the tray from the apparatus main body and an image forming apparatus including the sheet conveying apparatus, the force is as small as possible. The nip pressure is released. Therefore, it is possible to suppress an increase in the operating force required for removing the tray as the nip pressure is released. As a result, the tray can be easily detached.

1 is a perspective view of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a diagram illustrating an internal configuration of the image forming apparatus illustrated in FIG. 1. FIG. 4 is a perspective view of a sheet tray that is inserted into or pulled out of the image forming apparatus. It is the perspective view which looked at the sheet tray from the upper part. It is a top view of the conveyance unit which concerns on one Embodiment of this invention. It is a perspective view of the conveyance unit which concerns on one Embodiment of this invention. FIG. 4 is a side sectional view of the periphery of the first lever with the sheet tray detached. It is a sectional side view of the periphery of the 1st lever in the middle of mounting | wearing with a sheet tray. It is a sectional side view of the periphery of the 1st lever of the state in which the sheet | seat tray was mounted | worn. It is a sectional side view of the periphery of the 1st lever in the middle of detachment | leave of a sheet tray. It is a sectional side view of the periphery of the 1st lever in the middle of detachment | leave of a sheet tray. It is a rear view of the conveyance unit in a state where the second lever locks the support unit. It is a rear view of the conveyance unit in the state where the lock of the second lever is released.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following description, the term “sheet” means copy paper, coated paper, OHP sheet, cardboard, postcard, tracing paper, other sheet material subjected to image forming processing, or any processing other than image forming processing. Means the sheet material to receive. In addition, “downstream side in the first direction” means an arrowhead side in the first direction indicated by an arrow in each figure, and “upstream side in the first direction” similarly means a base end side of the arrow. And

  FIG. 1 is a perspective view of an image forming apparatus according to an embodiment of the present invention. FIG. 2 schematically shows an internal structure of the image forming apparatus shown in FIG. The image forming apparatus shown in FIGS. 1 and 2 is a so-called in-body discharge type copying machine, but in other embodiments, a printer, a facsimile machine, a multifunction machine having these functions, or a toner image on a sheet. Other devices for forming may be used.

  The image forming apparatus 1 includes a main housing 2 having a substantially rectangular parallelepiped shape. The main housing 2 connects a substantially rectangular parallelepiped lower housing 21, a substantially rectangular parallelepiped upper housing 22 disposed above the lower housing 21, and the lower housing 21 and the upper housing 22. And a connecting housing 23. The connection housing 23 extends along the right edge and the back edge of the main housing 2. The sheet subjected to the printing process is discharged into a discharge space 24 surrounded by the lower casing 21, the upper casing 22, and the connecting casing 23.

  The operation unit 221 protruding in the front direction of the upper housing 22 includes, for example, an LCD touch panel 222. The operation unit 221 is formed so as to be able to input information related to the image forming process. For example, the user can input the number of sheets to be printed, the print density, and the like through the LCD touch panel 222. Housed in the upper housing 22 are mainly an apparatus for reading an image of a document and an electronic circuit that controls the entire image forming apparatus 1.

  A pressing cover 223 disposed on the upper housing 22 is used for pressing the document. The presser cover 223 is attached to the upper housing 22 so as to be rotatable up and down. The user rotates the holding cover 223 upward to place the document on the upper housing 22. Thereafter, the user can operate the operation unit 221 to read an image of the document on a device provided in the upper housing 22.

  The lower casing 21 (casing) is provided with a sheet tray 500 on which a plurality of sheets are stacked. The sheet tray 500 is detachable from the lower housing 21. Specifically, the sheet tray 500 can be pulled out from the lower housing 21 in the front direction (the direction of the arrow D1 in FIG. 3). Further, the sheet tray 500 is attached to the lower casing 21 rearward (in the direction of arrow D1R in FIG. 3, the first direction). The sheet P stored in the sheet tray 500 is sent upward in the lower casing 21 and is subjected to image forming processing in the lower casing 21 based on an instruction input by the user through the operation unit 221. , Discharged to the discharge space 24.

  A tray 212 is rotatably attached to the right surface of the lower housing 21. As shown in FIG. 1, when the tray 212 is in a position protruding to the right of the lower housing 21, the user can place a sheet on the tray 212.

  The lower housing 21 accommodates various devices for forming an image on a sheet. Further, the connection housing 23 accommodates various devices for discharging the sheet subjected to the image forming process to the discharge space 24.

  The upper housing 22 accommodates the scanning mechanism 224. The user can cause the image forming apparatus 1 to read an image of a desired document through the scanning mechanism 224. Analog information of the image read by the scanning mechanism 224 is converted into a digital signal. The image forming apparatus 1 forms an image on a sheet based on the digital signal.

  The lower casing 21 accommodates toner containers 400Y, 400M, 400C, and 400Bk, an intermediate transfer unit 402, an image forming unit 403, an exposure unit 404, a fixing unit 47, a paper discharge unit 46, and a transport unit 3.

  The image forming unit 403 includes a photosensitive drum 17 that carries toner images of respective colors. As the photosensitive drum 17, a photosensitive drum using an amorphous silicon (a-Si) material can be used.

  Around the photosensitive drum 17, a charger 16, a developing device 10 (10Y, 10M, 10C, 10Bk), a transfer roller 19, and a cleaning device 18 are arranged. The transfer roller 19 forms a nip portion with the photosensitive drum 17 with the intermediate transfer belt 421 interposed therebetween, and primarily transfers the toner image on the photosensitive drum 17 onto the intermediate transfer belt 421. The cleaning device 18 cleans the peripheral surface of the photosensitive drum 17 after the toner image is transferred.

  Each of the developing devices 10Y, 10M, 10C, and 10Bk includes a developing case 20. A two-component developer having a magnetic carrier and toner is accommodated in the developing case 20. In the developing case 20, two stirring rollers 11 and 12 are rotatably arranged in parallel near the bottom of the developing case 20 with the longitudinal direction as the axial direction.

  The exposure unit 404 has various optical system devices such as a light source, a polygon mirror, a reflection mirror, and a deflection mirror. Light based on image data is provided on the peripheral surface of the photosensitive drum 17 provided in each of the image forming units 403. To form an electrostatic latent image.

  The intermediate transfer unit 402 includes an intermediate transfer belt 421, a driving roller 422, and a driven roller 423. On the intermediate transfer belt 421, toner images are overcoated from a plurality of photosensitive drums 17 (primary transfer). The overcoated toner image is secondarily transferred to the sheet supplied from the sheet tray 500 or the tray 212 (see FIG. 1) in the secondary transfer unit 48.

  The fixing unit 47 performs a fixing process on the toner image on the sheet secondarily transferred from the intermediate transfer unit 402.

  The paper discharge unit 46 discharges the sheet conveyed from the fixing unit 47 onto the upper surface 213 of the lower housing 21 used as a paper discharge tray.

  The transport unit 3 is disposed in the lower housing 21 so as to face the sheet tray 500. The transport unit 3 includes a pickup roller 310, a paper feed roller 320, and a transport roller 330. The pickup roller 310 and the paper feed roller 320 provided in the transport unit 3 are rotationally driven, whereby the uppermost sheet of the sheet bundle in the sheet tray 500 is taken out one by one. Further, the sheet is fed to the downstream side of the sheet conveyance path 133 by the conveyance roller 330 and introduced into the image forming unit 403. The pickup roller 310, the paper feed roller 320, and the conveyance roller 330 form a part of the sheet conveyance path 133 through which the sheet is conveyed to the image forming unit 403. The sheet conveyance path 133 extends from the sheet tray 500 in a second direction (arrow D2 in FIG. 3) that intersects the first direction.

<Structure of sheet tray>
FIG. 3 is a perspective view showing the sheet tray 500 inserted into the storage space 600 arranged in the lower housing 21 or the sheet tray 500 pulled out from the storage space 600.

  The sheet tray 500 is formed so as to be accommodated in the accommodation space 600. The user pulls out the sheet tray 500 from the accommodation space 600 when replenishing the sheet in the sheet tray 500 or exchanging the sheet in the sheet tray 500 for another sheet. In addition, the user pushes the sheet tray 500 into the accommodation space 600 when a new sheet is replenished in the sheet tray 500 or after the sheet in the sheet tray 500 is replaced with a new sheet. When the sheet tray 500 is stored in the storage space 600, the sheet tray 500 holds a sheet in the lower housing 21. The movement of the sheet tray toward the inside and outside of the accommodation space 600 is guided by the rail 613.

  FIG. 4 is a perspective view of the sheet tray 500. The sheet tray 500 includes a sheet tray housing 510 formed so as to be able to accommodate sheets. The sheet tray housing 510 includes a substantially rectangular bottom wall 511, a lift plate 530 laid on the bottom wall 511, a pair of side walls 512 erected upward from the periphery of the bottom wall 511, and a front wall 513. And a back wall 514. A front wall 513 extending between the front side edges of the pair of side walls 512 appears on the outer surface of the main housing 2 when the sheet tray housing 510 is completely accommodated in the accommodation space 600. The back wall 514 is disposed to face the front wall 513. Of the pair of side walls 512, the right side wall is a downstream wall 515 located downstream in the sheet conveyance direction, and the left side wall is an upstream wall 516 located upstream in the sheet conveyance direction. It is. Each of the pair of side walls 512 meshes with the rail 613, thereby guiding the movement of the sheet tray 500 in the front-rear direction (arrow D1, D1R direction). The front wall 513 includes a substantially U-shaped grip portion 518. The user can grip the grip portion 518 and move the sheet tray 500 in the front-rear direction. The upper edges of the pair of side walls 512, the front wall 513, and the back wall 514 form an opening 517 for accommodating sheets in the sheet tray 500. A user can store a sheet in the sheet tray housing 510 through the opening 517.

  The sheet tray 500 further includes a pair of guide members 520 adjacent to the front wall 513 and the back wall 514, respectively. The guide member 520 regulates the displacement in the width direction of the sheet disposed on the lift plate 530. A guide groove 521 for guiding the movement of the guide member 520 is formed in the bottom wall 511. The guide groove 521 extends from the front wall 513 toward the back wall 514. Therefore, the guide member 520 is movable in the sheet width direction. Thus, the user can bring the guide member 520 into contact with the side edge of a sheet of an arbitrary size.

  The lift plate 530 is disposed on the bottom wall 511 and includes a stacking surface on which sheets are stacked. In FIG. 4, the lift plate 530 is in a state where the sheet is stacked on the upper surface, the sheet conveyance direction downstream side (downstream wall 515 side) is lifted upward, and the stacked sheet is sent out toward the conveyance unit 3. be able to.

  Further, the sheet tray 500 includes a tray contact portion 550. The tray contact portion 550 is disposed on the upper surface of the rail 613 on the right side of the downstream wall 515. The tray contact portion 550 is a prismatic member that extends in the front-rear direction (first direction) along the downstream wall 515. The tray abutting portion 550 can abut on a first lever 80 and a second lever 90 described later in accordance with the attachment / detachment of the sheet tray 500 to the lower housing 21. The tray contact portion 550 includes a contact tip portion 550A and an opening 550B (see FIGS. 8 and 9). The abutting tip 550A is a rear end of the tray abutting portion 550 and abuts sequentially on a first lever 80 and a second lever 90 described later. The opening 550B is formed by cutting out a part of the tray contact portion 550 in the front-rear direction. A part of the first lever 80 described later can be immersed in the opening 550B.

<Conveyor unit structure>
Next, the transport unit 3 according to the embodiment of the present invention will be described with reference to FIGS. The conveyance unit 3 is combined with the sheet tray 500 to constitute the sheet conveyance device of the present invention.

  FIG. 5 is a plan view of the transport unit 3 according to the present embodiment. FIG. 6 is a perspective view of the transport unit 3. FIG. 7 is a side sectional view of the periphery of the first lever 80 in a state where the sheet tray 500 is detached from the lower housing 21 (second state). FIG. 8 is a side sectional view of the periphery of the first lever 80 while the sheet tray 500 is mounted on the lower housing 21. FIG. 9 is a side sectional view of the periphery of the first lever 80 in a state where the sheet tray 500 is attached to the lower housing 21 (first state). FIG. 10 is a side sectional view of the periphery of the first lever 80 while the sheet tray 500 is being detached from the lower housing 21. Similarly, FIG. 11 is a side sectional view of the periphery of the first lever 80 while the sheet tray 500 is being detached from the lower housing 21. FIG. 12 is a rear view of the transport unit 3 in a state where the second lever 90 locks the support unit 70. FIG. 13 is a rear view of the transport unit 3 in a state where the lock of the second lever 90 is released.

  The transport unit 3 is disposed above the sheet tray 500 in the lower housing 21 of FIG. The transport unit 3 spreads a bundle of sheets P lifted by the lift plate 530 (FIG. 4) one by one in the sheet tray 500, and the rolled sheets P in a second direction (each of the first directions intersecting the first direction). It is conveyed in the direction of arrow D2 in the figure. The sheet conveyance path 133 extends slightly in the second direction and then extends upward in the lower housing 21. As described above, since the transport unit 3 is fixedly disposed on the lower housing 21, the transport unit 3 is not pulled out of the lower housing 21 even if the user inserts or removes the sheet tray 500 in the front-rear direction. Absent.

  As shown in FIG. 6, the transport unit 3 has a substantially L-shaped shape protruding downward in a cross-sectional view including the vertical direction and the horizontal direction, and is a box-shaped unit that extends in the front-rear direction. It is. The transport unit 3 includes a pair of substantially L-shaped side walls 301 and 302 (FIG. 5) that form side surfaces, a right wall 303 that connects the side walls 301 and 302 and forms the front surface in the second direction of the transport unit 3, The first left wall 304a that forms the rear surface of the transport unit 3 in the second direction, the second left wall 304b that forms the L-shaped bent portion K, and the bent portion K are formed in the same manner, from the first left wall 304a. It is demarcated by the upper surface part 312 which consists of a substantially horizontal surface extended toward the 2nd left wall 304b side. The sheet P accommodated in the sheet tray 500 is conveyed toward the L-shaped bent portion K formed by the upper surface portion 312 and the second left wall 304b.

  The transport unit 3 includes a pickup roller 310 (feeding means), a paper feed roller 320 (paper feed means), a separation unit 321U (see FIG. 7), and a transport roller 330.

  The pickup roller 310 is rotatably supported at the central portion of the upper surface portion 312 in the sheet width direction (first direction). Specifically, the pickup roller 310 is supported by a pickup roller shaft 310 </ b> A that extends in the front-rear direction, and the pickup roller shaft 310 </ b> A is supported by the upper surface portion 312 of the transport unit 3. The pickup roller 310 is disposed to face the sheet P above the front edge of the sheet P in a state where the sheet P is accommodated in the sheet tray 500. The pickup roller 310 is rotationally driven at the entrance of the sheet conveyance path 133 to send out the sheet P in the sheet tray 500 to the sheet conveyance path 133. The pickup roller 310 moves between a paper feeding position that abuts on the top surface of the sheet bundle accommodated in the sheet tray 500 and a non-paper feeding position that is spaced upward from the top surface.

  The paper feed roller 320 is rotatably supported by a support shaft 314 (see FIG. 12), which is a rotation shaft, in the central portion of the upper surface portion 312 in the sheet width direction. The paper feed roller 320 is disposed at a predetermined interval downstream of the pickup roller 310 in the sheet conveyance direction. The sheet feed roller 320 rotates in contact with the sheet sent out by the pickup roller 310 and feeds the sheet downstream in the sheet conveyance direction. In particular, the sheet feeding roller 320 feeds only the sheet P positioned on the uppermost surface among the sheets fed by the pickup roller 310 toward the downstream side in the sheet conveying direction. The peripheral surface of the paper feed roller 320 is made of a rubber material.

  The separation unit 321U is disposed below the paper feed roller 320 and to the right of the second left wall 304b. The separation unit 321 </ b> U includes a retard roller 321 (separation unit) and a support unit 70.

  The retard roller 321 is disposed below the paper feed roller 320 so as to sandwich the sheet conveyance path 133 with the paper feed roller 320. The retard roller 321 forms a sheet feeding nip portion A where the sheet P is nipped with the sheet feeding roller 320. The retard roller 321 is rotatably supported by a retard shaft 321A (FIG. 12). The retard shaft 321A is supported by a support unit 70 described later. The retard roller 321 is disposed so as to protrude upward from an opening 304d formed in the second left wall 304b (FIG. 6). The retard roller 321 is rotated by the paper feed roller 320 in the paper feed nip A. For this reason, the retard roller 321 is disposed in contact with the paper feed roller 320. Even when a plurality of sheets are sent out by the pickup roller 310, the retard roller 321 prevents the sheets other than the sheet P positioned on the uppermost surface from being conveyed downstream in the sheet conveying direction. The peripheral surface of the retard roller 321 is made of a resin material.

  The support unit 70 (see FIG. 12) supports the retard roller 321 to be rotatable. The support unit 70 is a unit disposed inside the transport unit 3. The support unit 70 extends from the periphery of the retard roller 321 to the side wall 302 on the rear side of the transport unit 3 in the front-rear direction. Referring to FIG. 12, support unit 70 rotatably supports retard roller 321 at the left end portion. The support unit 70 includes a unit fulcrum part 70S. The unit fulcrum portion 70 </ b> S is a shaft portion that extends in the front-rear direction at the right and upper portion of the support unit 70 and is supported by the transport unit 3. The support unit 70 is rotated around the unit fulcrum part 70S inside the transport unit 3 so that the retard roller 321 side of the support unit 70 can move up and down.

  As the support unit 70 moves up and down, the retard roller 321 can be disposed at a first position where the retard roller 321 contacts the paper feed roller 320 and a second position spaced downward from the paper feed roller 320. Specifically, the retard roller 321 is disposed at the first position in the first state in which the sheet tray 500 is attached to the lower housing 21. At this time, the retard roller 321 is positioned at the first position via the support unit 70 by the first positioning portion 8 described later. The retard roller 321 is disposed at the second position in the second state in which the sheet tray 500 is detached from the lower housing 21. At this time, the retard roller 321 is positioned (locked) at the second position via the support unit 70 by the second positioning portion 9 described later.

  A film 450 is disposed immediately upstream of the retard roller 321 in the sheet conveyance direction. The film 450 guides the sheet P by the retard roller 321 so that the leading end of the sheet P does not break. The lower end of the film 450 is fixed to the second left wall 304b, and the upper portion of the film 450 is inclined and extended toward the sheet feeding nip portion A as a free end. Even when a plurality of sheets are fed toward the sheet feeding nip portion A, the film 450 is interposed between the retard roller 321 and the sheet. For this reason, it is difficult for the sheet and the retard roller 321 to come into contact with each other, and folding of the sheet leading end is suppressed.

  The transport roller 330 is disposed along the right wall 303 on the upper surface portion 312 (FIG. 5). The transport roller 330 is driven to rotate and further transports the sheet P fed by the paper feed roller 320 toward the downstream side of the sheet transport path 133. The conveyance roller 330 has a roller shaft and a plurality of roller portions arranged on the roller shaft at a predetermined interval. The roller shaft is rotatably supported on a pair of side walls 301 and 302 of the transport unit 3.

  Further, the transport unit 3 includes a first positioning unit 8 (first positioning unit) and a second positioning unit 9 (second positioning unit).

  The first positioning unit 8 positions the retard roller 321 at a first position where the sheet tray 500 contacts the paper feed roller 320 in the first state where the sheet tray 500 is mounted on the lower housing 21. The first positioning unit 8 releases the positioning of the retard roller 321 in conjunction with the removal of the sheet tray 500 from the lower housing 21. As a result, the retard roller 321 moves from the first position to the second position by the dead weight of the retard roller 321 (separating part 321U) including the support unit 70.

  The first positioning portion 8 is disposed at a position slightly rearward of the central portion in the front-rear direction of the second left wall 304 b of the transport unit 3. The first positioning portion 8 includes a first lever 80 (first movable member) and a biasing spring 304S (first biasing means).

  The first lever 80 is rotatably supported on the inner (right) side surface of the second left wall 304b. The first lever 80 includes a first fulcrum part 801 (first shaft part), an eleventh arm 802 (first contact part), a twelfth arm 803 (first contact part), and an engagement part 804. With. The first lever 80 rotates around the first fulcrum part 801.

  The first fulcrum part 801 is a shaft part extending in the left-right direction (second direction), and serves as a fulcrum for the rotation of the first lever 80. The first fulcrum part 801 is supported on the inner (right) side surface of the second left wall 304b.

  The eleventh arm 802 is an arm portion extending from the first fulcrum portion 801 toward the front (upstream side in the first direction). The eleventh arm 802 includes a first urging portion 802A. The first urging portion 802A can be brought into contact with the urged portion 703 of the support unit 70.

  The twelfth arm 803 is an arm portion extending from the first fulcrum portion 801 toward the rear (downstream in the first direction). The twelfth arm 803 includes a first tip portion 803A and a tray contact portion 805. The first tip 803A is the tip of the twelfth arm 803. The first tip 803A is formed with a notch on a substantially arc. As the first lever 80 rotates about the first fulcrum 801, the first tip 803A comes into contact with the rotation stop pin 304T (FIG. 7) disposed on the second left wall 304b, so that the first Excessive rotation of the lever 80 is prevented. The tray contact portion 805 (FIG. 10) is an outer peripheral portion below the twelfth arm 803. When the tray contact portion 550 of the sheet tray 500 contacts the tray contact portion 805, the first lever 80 is rotated around the first fulcrum portion 801. Note that the twelfth arm 803 is disposed so as to protrude below the lower surface portion of the transport unit 3 in order to contact the tray contact portion 550.

  The engaging portion 804 is a projecting piece that extends substantially upward from the first fulcrum portion 801 of the first lever 80. The distal end portion of the engaging portion 804 is bent substantially forward. One end of a biasing spring 304 </ b> S described later is fixed to the engaging portion 804.

  The aforementioned support unit 70 further includes a biased portion 703. The urged portion 703 is a projecting piece disposed behind the retard roller 321 in the support unit 70. The urged portion 703 protrudes from the left side surface 70L of the support unit 70 toward the left (the front side in FIG. 7). When the first urging portion 802A of the first lever 80 contacts the urged portion 703, the support unit 70 is moved upward from below.

  A support wall 304H is disposed on the second left wall 304b of the transport unit 3. The support wall 304 </ b> H is a wall portion extending downward in the transport unit 3.

  The biasing spring 304 </ b> S is bridged between the support wall 304 </ b> H and the engaging portion 804 of the first lever 80. The urging spring 304S urges the first lever 80 around the first fulcrum 801 in the direction in which the eleventh arm 802 (first urging portion 802A) urges the support unit 70 (in the direction of arrow D3 in FIG. 9). (Arrow D91 in FIG. 9).

  Due to the urging force of the urging spring 304S, the first positioning portion 8 causes the urged portion of the support unit 70 to move in the direction in which the retard roller 321 contacts the paper feed roller 320 (upward, the direction of arrow D3 in FIG. 9). 703 is activated.

  The second positioning unit 9 positions the retard roller 321 at a second position separated from the paper feed roller 320 in the second state in which the sheet tray 500 is detached from the lower housing 21. The second positioning portion 9 allows the biasing of the support unit 70 by the first positioning portion 8 in the first state, and allows the biasing by the first positioning portion 8 in the second state. While being regulated, the retard roller 321 is locked to the second position via the support unit 70.

  With reference to FIGS. 5, 6, and 12, the second positioning portion 9 is disposed on the side wall 302 on the rear side of the transport unit 3. The 2nd positioning part 9 is provided with the 2nd lever 90 and the urging means (2nd urging means) not shown. In the present embodiment, the first positioning unit 8 is disposed along the second left wall 304 b of the transport unit 3, and the second positioning unit 9 is disposed along the side wall 302. For this reason, the 1st positioning part 8 and the 2nd positioning part 9 are spaced apart, and it is suppressed that a specific area | region is largely occupied in the inside of the conveyance unit 3. FIG. Further, since the first positioning portion 8 and the second positioning portion 9 are spaced apart in the front-rear direction, a time difference is provided in the operation of the first lever 80 and the second lever 90 when the sheet tray 500 is attached / detached. Can do.

  The second lever 90 is rotatably supported on the side wall 302 of the transport unit 3. The second lever 90 includes a second fulcrum part 901 (second shaft part), a 21st arm 902 (second contact part), and a 22nd arm 903 (second contact part). The second lever 90 is rotatable around the second fulcrum part 901.

  The second fulcrum portion 901 is a shaft portion that extends in the front-rear direction, and serves as a shaft portion in the rotation of the second lever 90. The second fulcrum part 901 is supported on the side wall 302 of the transport unit 3.

  The twenty-first arm 902 is an arm portion extending substantially upward (in one direction) from the second fulcrum portion 901. The 21st arm 902 locks the support unit 70 disposed at the second position of the retard roller 321 at a position (third position) around the second fulcrum 901 shown in FIG. Specifically, the 21st arm 902 engages with the fixed tip end portion 70T1 of the fixing portion 70T protruding rearward from the rear side surface of the support unit 70 at the third position, and locks the support unit 70. .

  The 22nd arm 903 is an arm portion extending from the second fulcrum portion 901 in a direction different from the 21st arm 902. The 22nd arm 903 extends from the second fulcrum part 901 substantially to the left. The twenty-second arm 903 includes a pressed portion 903A at the tip. The pressed portion 903 </ b> A is in contact with the tray contact portion 550 of the sheet tray 500. Specifically, the pressed portion 903 </ b> A comes into contact with the tray contact portion 550 on the downstream side of the twelfth arm 803 of the first lever 80 in the mounting direction (first direction) of the sheet tray 500. In the present embodiment, in particular, the second lever 90 is disposed along the side wall 302. For this reason, the tray contact portion 550 contacts the pressed portion 903A at the final stage of the mounting operation of the sheet tray 500 to the lower housing 21. In addition, at the initial stage of the detaching operation of the sheet tray 500 from the lower housing 21, the tray contact portion 550 is detached from the pressed portion 903A.

  The urging means (not shown) is a spring member disposed between the 22nd arm 903 of the second lever 90 and the side wall 302 of the transport unit 3. The urging means urges the second lever 90 around the second fulcrum portion 901 so that the 21st arm 902 is disposed at the third position.

<Nip Formation at Feeding Nip A>
Next, the nip formation of the sheet feeding nip portion A accompanying the sheet tray 500 mounting operation will be described. FIG. 7 is a side sectional view of the transport unit 3 in the second state in which the sheet tray 500 is detached from the lower housing 21, as viewed from the left in FIG. In this case, since the sheet tray 500 is detached from the lower housing 21, the tray contact portion 550 of the sheet tray 500 is disposed apart from the twelfth arm 803 of the first lever 80. As shown in FIG. 12, the support unit 70 is moved downward with the unit fulcrum portion 70 </ b> S as a fulcrum, and the retard roller 321 is disposed at a second position separated from the paper feed roller 320. In this case, the second lever 90 is rotated around the second fulcrum portion 901 by the urging means (not shown), and the lock portion 902A of the 21st arm 902 is moved to the fixed distal end portion 70T1 of the fixing portion 70T of the support unit 70. Is engaged. Therefore, the state where the retard roller 321 is separated from the paper feed roller 320 is maintained. For this reason, in the second state where the sheet tray 500 is detached from the lower housing 21, the retard roller 321 is prevented from unnecessarily contacting the paper feed roller 320. As a result, it is possible to prevent the deformation of the surface of the paper feed roller 320 made of an elastic material. On the other hand, referring to FIG. 7, the first biasing portion 802A of the first lever 80 biases the biased portion 703 of the support unit 70 upward by the biasing force of the biasing spring 304S. . However, since the lock portion 902A of the second lever 90 positions (locks) the support unit 70 at the second position of the retard roller 321 as described above, the retard roller 321 moves toward the paper feed roller 320 side. There is nothing.

  As described above, in the second state, the second positioning unit 9 locks the support unit 70 at the second position of the retard roller 321 and the first positioning unit 8 attaches the support unit 70 in the third direction. The sheet tray 500 starts to be inserted into the lower housing 21 in a state of being urged. With reference to FIG. 8, when the sheet tray 500 enters the inside of the lower housing 21, the tray contact portion 550 of the sheet tray 500 contacts the twelfth arm 803 of the first lever 80. As a result, the first lever 80 is rotated in the directions of arrows D82 and D83 in FIG. 8 with the first fulcrum portion 801 as a fulcrum against the urging force of the urging spring 304S. At this time, the first urging portion 802 </ b> A of the first lever 80 is separated downward from the urged portion 703 of the support unit 70. However, at this stage, since the support unit 70 is locked by the lock portion 902A of the second positioning portion 9, the retard roller 321 does not move.

  Further, when the sheet tray 500 enters the inside of the lower casing 21, first, the contact tip 550A of the tray contact portion 550 contacts the pressed portion 903A of the second lever 90 (FIG. 13). As a result, the second lever 90 is rotated in the direction of arrow D132 in FIG. 13 with the second fulcrum portion 901 as a fulcrum against the urging force of the urging means. Accordingly, the support unit 70 is unlocked by the second positioning portion 9.

  Returning to FIG. 8, after the support unit 70 is unlocked by the second positioning portion 9, when the sheet tray 500 is further inserted and attached to the lower housing 21 (first state), the tray contact portion. An opening 550B of 550 is disposed to face the first lever 80 (FIG. 9). The twelfth arm 803 of the first lever 80 is immersed in the opening 550B. In other words, the twelfth arm 803 is not biased by the tray contact portion 550. Therefore, the first lever 80 is rotated in the direction of the arrow D91 in FIG. 9 with the first fulcrum part 801 as a fulcrum by the urging force of the urging spring 304S. As a result, the first urging portion 802A of the first lever 80 moves the urged portion 703 of the support unit 70 in the arrow D3 direction (third direction) in FIG. Similarly, in FIG. 13, the retard roller 321 side of the support unit 70 moves upward with the unit fulcrum part 70S as a fulcrum (arrow D131 in FIG. 13). As a result, the retard roller 321 is disposed at the first position where the retard roller 321 contacts the paper feed roller 320. As described above, the first urging portion 802A of the first lever 80 is once moved downward from the urged portion 703 of the support unit 70 before the lock of the support unit 70 by the second positioning portion 9 is released. Separate. For this reason, the 21st arm 902 of the 2nd lever 90 and the fixing | fixed part 70T of the support unit 70 do not rub strongly, and the damage of the 2nd positioning part 9 is prevented.

<Nip release of paper feed nip A>
Next, a description will be given of the nip release of the sheet feeding nip portion A accompanying the detaching operation of the sheet tray 500. When the sheet tray 500 starts to be pulled out forward (arrow D101 in FIG. 10) from the first state (FIGS. 9 and 13) in which the sheet tray 500 is mounted on the lower housing 21, first, the tray contact portion 550 is used. The opening 550 </ b> B is moved forward of the first lever 80. In other words, a portion of the tray contact portion 550 that is in front of the opening 550B contacts the tray contact portion 805 of the twelfth arm 803 of the first lever 80 (FIG. 10). As a result, the first lever 80 is rotated in the direction of arrow D102 in FIG. 10 with the first fulcrum portion 801 as a fulcrum. That is, the first urging portion 802 </ b> A of the first lever 80 is separated downward from the urged portion 703 of the support unit 70. Then, the support unit 70 including the retard roller 321 is rotated downward around the unit fulcrum 70S by its own weight. For this reason, the retard roller 321 is disposed at a second position spaced downward from the paper feed roller 320.

  Further, when the sheet tray 500 is pulled forward, the tray contact portion 550 of the sheet tray 500 is separated forward from the pressed portion 903 </ b> A of the second lever 90. As a result, the second lever 90 is rotated around the second fulcrum portion 901 by the urging force of the urging means. Then, the locking portion 902A of the second lever 90 locks the fixed distal end portion 70T1 of the fixing portion 70T of the support unit 70 that has already been disposed at the second position of the retard roller 321 by its own weight (FIG. 12).

  Further, when the sheet tray 500 is pulled forward, the tray contact portion 550 is moved forward relative to the first lever 80 as shown in FIG. As a result, the first lever 80 is rotated around the first fulcrum 801 again by the biasing force of the biasing spring 304S. Then, the first urging portion 802 </ b> A of the first lever 80 contacts the urged portion 703 of the support unit 70. However, since the support unit 70 is already locked at the second position of the retard roller 321 by the second positioning portion 9 at this stage, the support unit 70 is moved to the first position (supply by the first biasing portion 802A). It is not moved to the paper roller 320 side. Thus, in the second state in which the sheet tray 500 is detached from the lower housing 21, the retard roller 321 is stably disposed at the second position separated from the paper feed roller 320.

  As described above, according to the above-described embodiment, the first positioning unit 8 has the first position where the retard roller 321 contacts the paper feed roller 320 in the first state in which the sheet tray 500 is mounted on the lower housing 21. Position to. Further, the second positioning unit 9 positions the retard roller 321 at the second position separated from the paper feed roller 320 in the second state in which the sheet tray 500 is detached from the lower housing 21. Accordingly, the positioning of the retard roller 321 between the first position and the second position is realized by different means. When the sheet tray 500 is detached from the lower housing 21, the first positioning unit 8 releases the positioning of the retard roller 321 in conjunction with the removal of the sheet tray 500. Thereafter, the retard roller 321 is moved from the first position to the second position by its own weight. Further, the second positioning unit 9 locks the retard roller 321 at the second position in conjunction with the removal of the sheet tray 500. For this reason, a moving force for separating the retard roller 321 from the paper feed roller 320 is not required. For this reason, compared with the case where the retard roller 321 is directly separated from the paper feed roller 320 by the operation force of the sheet tray 500, the increase in the operation force is suppressed. Further, the retard roller 321 can be stably locked at the second position in conjunction with the detaching operation of the sheet tray 500. As a result, it is possible to prevent the retard roller 321 from unnecessarily contacting the paper feed roller 320 in a state where the sheet tray 500 is detached from the lower housing 21. Further, when the sheet tray 500 is detached from the lower housing 21, the sheet feeding nip portion A between the sheet feeding roller 320 and the retard roller 321 is released, so that the sheet P is sandwiched in the sheet feeding nip portion A. Even if it is, the sheet P can be detached from the sheet feeding nip portion A.

  Further, according to the above-described embodiment, even when the retard roller 321 is locked at the second position, the retard roller 321 is moved to the second position in conjunction with the operation of mounting the sheet tray 500 on the lower housing 21. The position can be moved to the first position.

  Further, according to the above-described embodiment, the first positioning unit 8 includes the support unit 70 including the retard roller 321 toward the third direction in which the retard roller 321 contacts the paper feed roller 320 in the first state. Rush. Further, in the second state, the first positioning unit 8 is restricted from being biased to the support unit 70 by the second positioning unit 9. The second positioning unit 9 allows the support unit 70 to be biased by the first positioning unit 8 in the first state. In the second state, the second positioning unit 9 locks the support unit 70 at the second position of the retard roller 321 in a state where the urging of the first positioning unit 8 to the support unit 70 is restricted. For this reason, the support unit 70 may be disposed at the first position and the second position of the retard roller 321 only by providing the first positioning portion 8 with a function of urging the support unit 70 in the third direction. It becomes possible.

  According to the above embodiment, the function of the first positioning portion 8 is realized by the first lever 80 including the first fulcrum portion 801, the twelfth arm 803, and the eleventh arm 802, and the biasing spring 304S. Is done.

  Further, according to the above-described embodiment, the support unit 70 can be moved by the first positioning unit 8 in conjunction with the attaching / detaching operation of the sheet tray 500. Particularly, when the twelfth arm 803 is immersed in the opening 550B formed in the tray contact portion 550, the rotation restriction of the first lever 80 is released, and the support unit 70 is moved from the second position of the retard roller 321 to the second position. Moved to position 1.

  Further, according to the above-described embodiment, the second lever 90 including the second fulcrum portion 901, the 22nd arm 903, and the 21st arm 902, and the urging means (not shown, second urging means) The function of the second positioning unit 9 is realized. In particular, the support unit 70 can be locked and unlocked by the second positioning portion 9 in conjunction with the attaching / detaching operation of the sheet tray 500.

  Further, according to the image forming apparatus 1 including the sheet tray 500 and the conveyance unit 3 described above, a moving force for separating the retard roller 321 from the paper feed roller 320 is not required. For this reason, compared with the case where the retard roller 321 is directly separated from the paper feed roller 320 by the operation force of the sheet tray 500, the increase in the operation force is suppressed. Further, the retard roller 321 can be stably locked at the second position in conjunction with the detaching operation of the sheet tray 500. As a result, it is possible to prevent the retard roller 321 from unnecessarily contacting the paper feed roller 320 in a state where the sheet tray 500 is detached from the lower housing 21. Further, when the sheet tray 500 is detached from the lower housing 21, the sheet feeding nip portion A between the sheet feeding roller 320 and the retard roller 321 is released, so that the sheet P is sandwiched in the sheet feeding nip portion A. Even if it is, the sheet P can be detached from the sheet feeding nip portion A. For this reason, sheet clogging hardly occurs inside the image forming apparatus 1, and an image is stably formed on the sheet.

  In addition, this invention is not limited to these embodiment, For example, the following modified embodiment is employable.

  (1) In the embodiment described above, the first positioning unit 8 is disposed along the second left wall 304b of the transport unit 3 and the second positioning unit 9 is disposed along the side wall 302. However, the present invention is not limited to this. The first positioning unit 8 and the second positioning unit 9 may be arranged at other locations in the transport unit 3.

  (2) In the above embodiment, the first urging portion 802A of the first lever 80 is once urged by the support unit 70 before the lock of the support unit 70 by the second positioning portion 9 is released. Although the embodiment has been described as being spaced apart from the portion 703, the present invention is not limited to this. The first lever 80 may not be separated from the support unit 70 before the support unit 70 is unlocked by the second positioning unit 9.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 133 Sheet conveyance path 2 Main housing | casing 21 Lower housing | casing (casing)
3 Conveyance unit 304H Support wall 304S Biasing spring (first biasing means)
310 Pickup roller (delivery means)
310A Pickup roller shaft 320 Paper feed roller (paper feed means)
321 retard roller (separation means)
321A Retarded shaft 321U Separating part 330 Conveying roller 500 Sheet tray 515 Downstream wall 550 Tray contact part (contact member)
550A Abutting tip portion 550B Opening portion 70 Support unit 703 Energized portion 70S Unit fulcrum portion 70T Fixing portion 70T1 Fixing tip portion 8 First positioning portion (first positioning means)
80 First lever (first movable member)
801 First fulcrum (first shaft)
802 11th arm (first contact portion)
802A First urging portion 803 12th arm (first contacted portion)
803A 1st front-end | tip part 804 Engagement part 9 2nd positioning part (2nd positioning means)
90 Second lever (second movable member)
901 Second fulcrum part (second shaft part)
902 21st arm (second contact portion)
902A Lock portion 903 22nd arm (second contacted portion)
903A Pressed part

Claims (5)

A housing,
A sheet tray that is detachable from the housing, a plurality of sheets are stacked therein, and is mounted in the first direction with respect to the housing;
A sheet conveyance path disposed in the housing and extending from the sheet tray in a second direction intersecting the first direction;
A sending means arranged opposite to the sheets stacked on the sheet tray, driven to rotate, and sending the sheets to the sheet conveying path;
A paper feed roller that is rotatably supported by the housing, abuts on the sheet delivered by the delivery means, is rotationally driven, and feeds the sheet to the downstream side in the second direction of the sheet conveyance path;
Is opposed to the sheet feed roller, and the retard roller the feed nip formed between the sheet feeding roller, for separating the sheet and the other sheet being the sheet of paper,
In the first state in which the sheet tray is attached to the housing, a first positioning means for positioning a first position abutting said retard roller to said feeding roller,
In the second state in which the sheet tray is detached from the housing, and a second positioning means for positioning said retard roller to a second position spaced apart from the paper feed roller,
A supporting unit that includes a fulcrum portion extending in the first direction, is supported by the housing so as to be rotatable around the fulcrum portion, and supports the retard roller rotatably;
Have
The first positioning means includes
A first shaft portion extending in the second direction; a first contacted portion extending downstream from the first shaft portion in the first direction and contacting the sheet tray; and the first shaft portion A first abutting portion that extends upstream from the first direction, abuts on the support unit, and urges the support unit in a third direction in which the retard roller abuts on the paper feed roller. A first movable member rotatable around the first shaft portion;
First biasing means for biasing the first movable member around the first shaft portion in a direction in which the first contact portion biases the support unit;
Further, in conjunction with the sheet tray being detached from the housing, the positioning of the retard roller at the first position is released, and the retard roller is moved from the first position by its own weight. The second unit is allowed to move to the second position, and in the first state, the support unit is urged toward the third direction, and in the second state, the second positioning unit supports the support. The energization of the unit is regulated,
The second positioning means locks the retard roller that has moved to the second position in conjunction with the removal of the sheet tray from the housing , and in the first state, the first positioning The urging of the support unit by the means is allowed, and in the second state, the urging of the support unit to the support unit by the first positioning means is restricted, and the support unit is moved to the first of the retard roller. Locked in position 2,
The sheet tray includes a contact member extending in the first direction and capable of contacting the first contacted portion,
The contact member includes an opening that is partially opened in the first direction and into which the first contacted part can be immersed.
With the change from the first state to the second state, the contact member comes into contact with the first contacted portion of the first movable member, so that the first movable member is moved to the first state. The first abutting means is rotated around the first shaft portion against the urging force of the urging means, the first abutting portion is separated from the support unit, and the retard roller includes the support unit by its own weight. Is located at
With the change from the second state to the first state, the first contacted part is immersed in the opening of the contact member, and the first movable member is the first biasing means. The sheet is rotated around the first shaft portion by the urging force, and the retard roller is disposed at the first position by the first contact portion contacting the support unit. Conveying device. The second positioning means unlocks the retard roller disposed at the second position in conjunction with the operation of mounting the sheet tray on the housing,
The first positioning means moves the retard roller , which has been unlocked, from the second position to the first position in conjunction with the operation of mounting the sheet tray on the housing. The sheet conveying apparatus according to claim 1, wherein: The second positioning means includes
A second shaft portion that extends in one direction from the second shaft portion and locks the support unit disposed at the second position at a third position around the second shaft portion. A second portion to be in contact with the contact member on the downstream side in the first direction with respect to the first contact portion, extending in a direction different from the lock portion from the contact portion and the second shaft portion. A second movable member comprising a contact portion and rotatable about the second shaft portion;
And a second urging means for urging the second movable member around the second shaft portion so that the second abutting portion is disposed at the third position. Item 3. The sheet conveying apparatus according to Item 1 or 2 . In accordance with the change from the second state to the first state, the abutting member abuts on the second abutted portion, whereby the second movable member is attached to the second urging means. It is rotated around the second shaft portion against the force, and the lock of the support unit by the second contact portion is released,
With the change from the first state to the second state, the contact member is separated from the second contacted portion, so that the second movable member is moved by the second biasing means. It is rotated around the second shaft portion by an urging force, the second contact portion is disposed at the third position, and the support unit is locked at the second position of the retard roller. The sheet conveying apparatus according to claim 3 . A sheet conveying apparatus according to any one of claims 1 to 4 ,
An image forming unit that forms an image on the sheet conveyed by the sheet conveying device;
An image forming apparatus comprising: