Sheet feeding device and image forming device

Abstract

This sheet feeding device comprises: a device body (1A); a sheet support part (31); a feeding unit (32) attachable to and detachable from the device body (1A), the feeding unit (32) having a feeding roller (110), a holding member (113) movably supported and rotatably holding the feeding roller (110), and a first restricting member (123); and a second restricting member (152) provided in the device body (1A). When the sheet support part (31) is attached to the device body (1A) in a state in which the feeding unit (32) is attached to the device body (1A), the holding member (113) moves from a second holding position to a third holding position as a result of the first restricting member (123) being pressed by the sheet support part (31) and moving from a first restricting position to a first allowing position, and moves from the third holding position to a first holding position as a result of the second restricting member (152) being pressed by the sheet support part (31) and moving from a second restricting position to a second allowing position.

Description

Sheet feeding device and image forming apparatus

[0001] The present disclosure relates to a sheet feeding device that feeds sheets and an image forming apparatus including the same.

[0002] Conventionally, an image forming apparatus has been proposed that includes a paper feed cassette that can be pulled out from the main body of the apparatus and stores sheets, and a paper feed unit that is provided in the main body of the apparatus and feeds the sheets stored in the paper feed cassette (see Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2024-7129

[0004] However, the paper feed unit described in Patent Document 1 is located deep within the device body, and there are problems with maintenance when replacing rollers such as the pickup roller, pickup roller and retard roller provided in the paper feed unit.

[0005] Therefore, an object of the present disclosure is to provide an embodiment of a sheet feeding device with improved maintainability of the feeding roller and an image forming apparatus including the same.

[0006] According to a first aspect of the present disclosure, a sheet feeding device includes: an apparatus main body; a sheet support section configured to be attachable to the apparatus main body in an attachment direction and to be withdrawable in a withdrawal direction opposite to the attachment direction and to support sheets; a feeding unit detachable from the apparatus main body, the feeding roller being movable up and down to an abutting position at which it can abut against a top sheet supported by the sheet support section and a retracted position at which it is retracted above the abutting position so as to be spaced apart from the top sheet; and a holding member supported to be swingable and to rotatably hold the feeding roller, a holding member that is swingable to a first holding position that holds the feed roller at the abutting position, a second holding position that holds the feed roller at the retracted position, and a third holding position between the first holding position and the second holding position; a first restricting member that is movable to a first restricting position that restricts the holding member from swinging from the second holding position to the third holding position by abutting against the holding member that is located at the second holding position, and a first allowing position that allows the holding member to swing from the second holding position to the third holding position; a second restricting member that is movable between a second restricting position where the second restricting member comes into contact with the holding member that is located at the third holding position to restrict the holding member from swinging from the third holding position to the first holding position, and a second allowing position where the holding member is allowed to swing from the third holding position to the first holding position, and the first restricting member and the second restricting member are respectively located at the first restricting position and the second restricting position when the sheet supporting section is pulled out from the device main body, and the sheet supporting section is located at a position where the feeding unit is attached. when the sheet support section is attached to the device body, the holding member abuts against the first restricting member positioned at the first restricting position at a first abutting position, and abuts against the second restricting member positioned at the second restricting position at a second abutting position downstream of the first abutting position in the attachment direction, and when the sheet support section is attached to the device body with the feeding unit attached to the device body, the first restricting member is pressed by the sheet support section to move from the first restricting position to the first allowing position, thereby causing the holding member to swing from the second holding position to the third holding position,The second restricting member is pressed by the seat support portion and moves from the second restricting position to the second allowing position, thereby swinging from the third holding position to the first holding position.

[0007] According to a second aspect of the present disclosure, a sheet feeding device includes: an apparatus main body; a sheet support section configured to be mountable to the apparatus main body in an installation direction and to be pull-out in a pull-out direction opposite to the installation direction and to support sheets; a feeding unit detachable from the apparatus main body, the feeding roller being movable up and down between an abutting position at which it can abut against a top sheet supported by the sheet support section and a retracted position at which it is retracted above the abutting position so as to be spaced apart from the top sheet; and a holding member supported to be swingable and to rotatably hold the feeding roller, a holding member that is swingable to a first holding position that holds the feed roller at the abutting position, a second holding position that holds the feed roller at the retracted position, and a third holding position between the first holding position and the second holding position; a first restricting member that is movable to a first restricting position that restricts the holding member from swinging from the second holding position to the third holding position by abutting against the holding member that is positioned at the second holding position, and a first allowing position that allows the holding member to swing from the second holding position to the third holding position; a second restricting member movable between a second restricting position and a second allowing position, the second restricting member being movable to a second restricting position and a second allowing position, the second restricting member being movable to a second allowing position and a second allowing position, the second restricting member being movable to a second restricting ... when the sheet support section is attached to the device body, the holding member abuts against the first restricting member located at the first restricting position at a first abutting position, and abuts against the second restricting member located at the second restricting position at a second abutting position downstream of the first abutting position in the attachment direction, and when the sheet support section is attached to the device body with the feeding unit attached to the device body, the first restricting member is pressed by the sheet support section and moves from the first restricting position to the first allowable position, thereby causing the holding member to swing from the second holding position to the third holding position,The second restricting member is pressed by the seat support portion and moves from the second restricting position to the second allowing position, thereby swinging from the third holding position to the first holding position.

[0008] According to the present disclosure, the ease of maintenance of the feed roller can be improved.

[0009] Other features and advantages of the present disclosure will become apparent from the following description taken in conjunction with the accompanying drawings, in which the same or similar components are designated by the same reference numerals.

[0010] The present invention relates to an image forming apparatus having a structure in which a second restricting member is provided and a cassette is inserted into the image forming apparatus, and a second restricting member is provided in the second restricting member and a cassette is inserted into the image forming apparatus, and the second restricting member and a cassette are ...

[0011] [Overall Configuration] The image forming apparatus 1 according to this embodiment is an electrophotographic laser beam printer, and as shown in FIG. 1, has an image forming section 10 that forms an image on a sheet S, a fixing section 20, sheet feeding devices 30, 130, 230, and a sheet supporting device 40.

[0012] The image forming apparatus includes printers, copiers, facsimiles, and multifunction peripherals, and refers to an apparatus that forms an image on a sheet used as a recording medium based on image information input from an external PC or image information read from an original. In addition, an image forming apparatus may be connected to accessories such as an optional feeder, an image reader, and a sheet processing device in addition to a main body having an image forming function, and the entire system connected with such accessories is also a type of image forming apparatus.

[0013] The image forming unit 10 includes four process cartridges 11Y, 11M, 11C, and 11Bk that form toner images of four colors, yellow (Y), magenta (M), cyan (C), and black (Bk), respectively, and a scanner unit 15. The four process cartridges 11Y, 11M, 11C, and 11Bk have the same configuration except for the colors of the images they form. Therefore, only the configuration and image forming process of the process cartridge 11Y will be described, and descriptions of the process cartridges 11M, 11C, and 11Bk will be omitted.

[0014] The process cartridge 11Y has a photosensitive drum 12, a charging roller 13, and a developing roller 14. The photosensitive drum 12 is constructed by coating the outer periphery of an aluminum cylinder with an organic photoconductive layer, and is rotated by a drive motor (not shown). The image forming unit 10 also has an intermediate transfer belt 18 wound around a drive roller 16 and a tension roller 17, and primary transfer rollers 19Y, 19M, 19C, and 19Bk are provided inside the intermediate transfer belt 18.

[0015] The fixing section 20 has a fixing film 21 that is heated by a heater (not shown), and a pressure roller 22 that is in pressure contact with the fixing film 21. The sheet feeding device 30, 130, 230 is provided at the bottom of the image forming apparatus 1, and includes a cassette 31, 131, 231 that stores sheets, and a feeding unit 32, 132, 232 that feeds the sheets.

[0016] Next, we will explain the image forming operation of the thus configured image forming apparatus 1. When an image signal is input to the scanner unit 15 from a personal computer (not shown) or the like, the scanner unit 15 irradiates the photosensitive drum 12 of the process cartridge 11Y with a laser beam corresponding to the image signal.

[0017] At this time, the surface of the photosensitive drum 12 is uniformly charged to a predetermined polarity and potential by the charging roller 13, and an electrostatic latent image is formed on the surface by irradiating it with laser light from the scanner unit 15. The electrostatic latent image formed on the photosensitive drum 12 is developed by the developing roller 14, and a yellow (Y) toner image is formed on the photosensitive drum 12.

[0018] Similarly, the scanner unit 15 irradiates the photosensitive drums of the process cartridges 11M, 11C, and 11Bk with laser light, forming magenta (M), cyan (C), and black (Bk) toner images on the respective photosensitive drums. The toner images of each color formed on the respective photosensitive drums are transferred onto the intermediate transfer belt 18 by primary transfer rollers 19Y, 19M, 19C, and 19Bk, and are then transported to the secondary transfer roller 25 by the intermediate transfer belt 18, which is rotated by the drive roller 16. The image formation process for each color is performed at a timing to overlap the upstream toner image that has been primarily transferred onto the intermediate transfer belt 18.

[0019] In parallel with this image forming process, a sheet S is fed from one of the sheet feeding devices 30, 130, and 230. Since the sheet feeding devices 30, 130, and 230 each have the same configuration, the following description will be given taking as an example a case where the sheet S is fed from the sheet feeding device 30. Note that the cassettes 31, 131, and 231 may each store sheets of different sizes.

[0020] A sheet S stored in a cassette 31 of the sheet feeding device 30 is fed by a feeding unit 32 and then conveyed to a pair of registration rollers 35. The sheet S, whose skew has been corrected by the pair of registration rollers 35, is conveyed to a main conveying path 43 at a predetermined conveying timing. Then, the full-color toner image on the intermediate transfer belt 18 is transferred onto the sheet S by a secondary transfer bias applied to a secondary transfer roller 25.

[0021] The sheet S onto which the toner image has been transferred is subjected to predetermined heat and pressure by a fixing film 21 and a pressure roller 22 of the fixing unit 20, thereby melting and fixing (fixing) the toner. The sheet S that has passed through the fixing unit 20 is discharged onto a discharge tray 27 by a pair of discharge rollers 26.

[0022] When performing double-sided printing, in which images are formed on both sides of a sheet S, the sheet S with an image formed on its first side is conveyed toward a double-sided conveying path 41 by the reverse rotation of the discharge roller pair 26. The sheet S is conveyed by a double-sided conveying roller pair 42 provided on the double-sided conveying path 41 and merges with a main conveying path 43. Then, the toner image on the intermediate transfer belt 18 is transferred to a second side of the sheet S, which is opposite to the first side, and the sheet S is discharged onto a discharge tray 27 by the discharge roller pair 26.

[0023] The image forming apparatus 1 also includes an apparatus main body 1A, which supports a sheet support device 40 in an openable and closable manner. The cassettes 31, 131, and 231 are configured to be installable in the apparatus main body 1A in an installation direction AD (described later) and removable in a removal direction DD (see FIG. 2). The sheet support device 40 includes a main body 50, a transfer unit 60, and a sheet support unit 70. The sheet support unit 70 is configured to be rotatable about a rotation shaft 71 relative to the main body 50 and can support a sheet when opened relative to the main body 50. A sheet supported by the sheet support unit 70 can be fed by a pickup roller (not shown), and the fed sheet merges with the main conveyance path 43. The main body 50 is supported in an openable and closable manner about the rotation shaft 51 relative to the apparatus main body 1A. The transfer unit 60 is supported in an openable and closable manner about the rotation shaft 61 relative to the main body 50 and supports a secondary transfer roller 25 and other components.

[0024] A main transport path 43 is formed between the device main body 1A and the transfer unit 60, and the main transport path 43 is opened by opening the transfer unit 60 together with the main body 50 relative to the device main body 1A. In addition, by opening the transfer unit 60 relative to the main body 50 in this state, the duplex transport path 41 between the main body 50 and the transfer unit 60 is opened. In this way, by configuring the main transport path 43 and the duplex transport path 41 to be openable, jam clearance can be improved.

[0025] [Feeding Unit] Next, the feeding unit 32 will be described using FIGS. 1 to 5. The feeding units 132 and 232 described above have the same configuration as the feeding unit 32, and therefore their description will be omitted. FIG. 2 is a perspective view showing the feeding unit 32 pulled out from the apparatus main body 1A. FIG. 3 is a perspective view showing the feeding unit 32. FIG. 4 is a perspective view showing the feeding unit 32 attached to the apparatus main body 1A. FIG. 5 is a perspective view showing the feeding unit 32 when the feeding unit 32 and cassette 31 are attached to the apparatus main body 1A. In FIG. 4, the cassette 31 is located in the attached position in the apparatus main body 1A, and with the cassette 31 located in the attached position, the image forming apparatus 1 can perform an image formation process.

[0026] 1 to 4, the feeding unit 32 is configured to be attachable to the apparatus main body 1A in an attachment direction AD and to be removable in a removal direction DD opposite to the attachment direction AD. The feeding unit 32 has a pickup roller 110 as a feeding roller that feeds the sheets S stored in the cassette 31, and a conveying roller 111 that conveys the sheets S fed by the pickup roller 110. The feeding unit 32 also has a separation roller 112 that abuts against the conveying roller 111 and separates the sheets S one by one together with the conveying roller 111, and a pickup arm 113 as a holding member that rotatably holds the pickup roller 110.

[0027] Furthermore, the feeding unit 32 has a feeding frame 120 and a conveying roller shaft 114 that is rotatably supported by the feeding frame 120 and rotatably supports the conveying roller 111. The conveying roller shaft 114 as a rotating shaft engages with a coupling 115 provided in the apparatus main body 1A when the feeding unit 32 is attached to the apparatus main body 1A. This allows driving force to be transmitted from the coupling 115 to the conveying roller shaft 114. A conveying roller gear 116 is fixed to the conveying roller shaft 114.

[0028] The pickup arm 113 is swingably supported by the transport roller shaft 114, and rotatably holds the pickup roller 110 via the pickup roller shaft 110a. A pickup gear 117 is fixed to the pickup roller shaft 110a. The pickup arm 113 also rotatably supports an idler gear 118 that meshes with the transport roller gear 116 and the pickup gear 117.

[0029] The rotation of the conveying roller gear 116, which rotates together with the conveying roller shaft 114, is transmitted to the pickup gear 117 via the idler gear 118. Then, as the pickup gear 117 rotates, the pickup roller shaft 110a and the pickup roller 110 rotate. The separation roller 112 is in pressure contact with the conveying roller 111 with a predetermined contact pressure, and is rotated by the conveying roller 111. In this way, as the drive is transmitted from the apparatus main body 1A to the conveying roller shaft 114, the pickup roller 110, the conveying roller 111, and the separation roller 112 rotate.

[0030] The separation roller 112 has a built-in torque limiter, and when multiple sheets S enter the separation nip between the conveying roller 111 and the separation roller 112, the separation roller 112 does not rotate in response to the conveying roller 111. On the other hand, when only one sheet S enters the separation nip, the separation roller 112 rotates in response to the conveying roller 111 via the sheet S. A drive force may be input to the separation roller 112 so that the separation roller 112 rotates in a direction returning the sheet S toward the cassette 31.

[0031] 4, a coil portion 121a of a torsion coil spring 121 serving as a third biasing member is attached to the conveyance roller shaft 114. The torsion coil spring 121 has a first locking portion 121b extending in one direction from the coil portion 121a and a second locking portion 121c extending in the other direction from the coil portion 121a. The first locking portion 121b is locked to the feed frame 120 of the feed unit 32, and the second locking portion 121c is locked to the pickup arm 113. As a result, the pickup arm 113 is biased to swing downward about the conveyance roller shaft 114.

[0032] Here, the pickup arm 113 swings, allowing the pickup roller 110 to move up and down between a contact position where it can contact the topmost sheet supported in the cassette 31 and a retracted position where it is retracted above the contact position and is spaced apart from the topmost sheet. The pickup arm 113 is configured to swing between a first holding position (position shown in FIG. 1 ) where the pickup roller 110 is held in the contact position and a second holding position (position shown in FIG. 5 ) where the pickup roller 110 is held in the retracted position. The position between the first and second holding positions is referred to as a third holding position, which will be described in detail later. The torsion coil spring 121 described above biases the pickup arm 113 toward the first holding position.

[0033] 2 to 5, the feeding unit 32 includes a first restricting member 123 supported by the feeding frame 120 to be rotatable about a rotation shaft 122, and a spring 124 serving as a first biasing member for biasing the first restricting member 123. The rotation shaft 122 serving as the first rotation shaft extends in a cross direction D1, which serves as a first cross direction intersecting the mounting direction AD and the pull-out direction DD. The cross direction D1 is parallel to the horizontal direction and is along the feeding direction FD in which the pickup roller 110 feeds the sheets S. The first restricting member 123 includes a pressed portion 123a and a pressing portion 123b. The pressed portion 123a is pressed against the cassette 31, as described below. The pressing portion 123b presses a contact portion 113a of the pickup arm 113, thereby causing the pickup arm 113 to swing toward the second holding position.

[0034] The first restricting member 123 is configured to be movable between a first restricting position and a first allowable position. In the first restricting position, the pressing portion 123b of the first restricting member 123 abuts against the pickup arm 113 located at the second holding position, thereby restricting the pickup arm 113 from swinging from the second holding position toward the third holding position. In addition, in the first allowable position, the first restricting member 123 allows the pickup arm 113 to swing from the second holding position toward the third holding position.

[0035] When first restricting member 123 moves from the first restricting position to the first permissible position, pressing portion 123b moves down, causing pickup arm 113 to move from the second holding position to the third holding position. Conversely, when first restricting member 123 moves from the first permissible position to the first restricting position, pressing portion 123b presses contact portion 113a of pickup arm 113, thereby pushing pickup arm 113 up from the third holding position to the second holding position. Spring 124 is stretched between feed frame 120 and first restricting member 123 and biases first restricting member 123 toward the first restricting position.

[0036] Furthermore, the pickup arm 113 is provided with an arm flag 113b that swings integrally with the pickup arm 113. The feeding unit 32 has a sheet presence flag 125 that is supported by the feeding frame 120 so as to be swingable.

[0037] [Second Restriction Member] Next, the second restriction member 152 and its surrounding structure will be described with reference to Figures 2 to 6. Figure 6 is a perspective view showing the second restriction member 152 and its surrounding structure in a state where the cassette 31 is pulled out.

[0038] As shown in Fig. 2, the apparatus main body 1A has a storage space SP in which the cassette 31 and the feeding unit 32 are stored. As shown in Fig. 6, the apparatus main body 1A has a main body frame 150 as a frame provided at the back of the storage space SP in the installation direction AD, and a mounting member 151 attached to the main body frame 150. The apparatus main body 1A also has a guide rail 159 fixed to the main body frame 150 for guiding the cassette 31 in the installation direction AD and the pull-out direction. A second regulating member 152, a sheet presence / absence sensor 153 as a first detector, and an arm sensor 154 as a second detector are supported on the mounting member 151.

[0039] The sheet presence sensor 153 and the arm sensor 154 are optical sensors each having a light-emitting portion and a light-receiving portion, and an optical path is formed between these light-emitting portion and light-receiving portion. That is, the sheet presence sensor 153 has an optical path LP1, and the arm sensor 154 has an optical path LP2. The sheet presence flag 125 described above abuts from above against the uppermost sheet contained in the cassette 31 when the cassette 31 and the feeding unit 32 are attached to the apparatus main body 1A. The sheet presence flag 125 is configured to be swingable by its own weight so that it is always in contact with the uppermost sheet contained in the cassette 31.

[0040] An opening (not shown) is provided in the stacking plate 31a (see FIG. 1) on which the sheets S are stacked, and when no sheets S are placed on the stacking plate 31a, the sheet presence / absence flag 125 is positioned at a lower position where it enters the opening. The stacking plate 31a is supported so that it can be raised and lowered by driving the lift plate 31b, and is configured to rise as the number of sheets S stacked on the stacking plate 31a decreases when the cassette 31 and the feeding unit 32 are attached to the apparatus main body 1A. This allows the surface position of the top sheet stacked on the stacking plate 31a to be kept approximately constant, and the sheet S can be fed by the pickup roller 110 with an appropriate feeding pressure.

[0041] When at least one sheet S is stored in the cassette 31 serving as a sheet support unit, the optical path LP1 of the sheet presence / absence sensor 153 is blocked by the sheet presence / absence flag 125, and the sheet presence / absence sensor 153 is OFF. When there are no more sheets in the cassette 31, the sheet presence / absence flag 125 moves to the lower position, and the optical path LP1 of the sheet presence / absence sensor 153 is no longer blocked by light. This turns the sheet presence / absence sensor 153 ON, making it possible to detect that there are no more sheets in the cassette 31. In other words, the sheet presence / absence sensor 153 can detect whether or not a sheet is being supported in the cassette 31.

[0042] Furthermore, arm sensor 154 can detect arm flag 113b, which swings integrally with pickup arm 113. For example, when an image formation job for forming an image on a sheet S is input, lift plate 31b described above is driven, and stack plate 31a is raised. As a result, the top sheet S stacked on stack plate 31a comes into contact with pickup roller 110, which is positioned at the contact position. Note that stack plate 31a stops at a position where pickup roller 110 is pushed slightly further upward after the top sheet S comes into contact with pickup roller 110, and the position of pickup roller 110 at this time is also considered the contact position.

[0043] As sheets S stored in cassette 31 are fed in accordance with an image formation job, the surface position of the top sheet stacked on stacking plate 31a moves downward. Because pickup arm 113 is biased by torsion coil spring 121 to swing downward, pickup arm 113 also swings downward in conjunction with the downward movement of the surface position of the top sheet. When pickup arm 113 passes a predetermined position, arm flag 113b provided on pickup arm 113 moves out of optical path LP2 of arm sensor 154, and optical path LP2 is no longer blocked. This turns arm sensor 154 ON. In other words, arm sensor 154 detects the position of pickup arm 113.

[0044] When the arm sensor 154 is turned ON, the lift plate 31b is driven by a control unit (not shown) by a predetermined amount. As a result, the stack plate 31a is raised by the predetermined amount, and the light path LP2 of the arm sensor 154 is again blocked by the arm flag 113b, turning the arm sensor 154 OFF. In other words, each time a predetermined number of sheets S in the cassette 31 are fed, the lift plate 31b is driven so that the stack plate 31a is raised by the predetermined amount. In this way, the arm sensor 154 detects the position of the pickup arm 113, but it can also be said that it detects the paper surface position of the topmost sheet stacked on the stack plate 31a.

[0045] 4 and 6 , the second restricting member 152 is disposed downstream of the first restricting member 123 in the mounting direction AD. The second restricting member 152 is rotatably supported by the mounting member 151 around a rotation shaft 155, and has a pressed portion 152a that is pressed against the cassette 31, and a support portion 152b that supports the pickup arm 113 at the third holding position. Unlike the rotation shaft 122 of the first restricting member 123, the rotation shaft 155 serving as the second rotation shaft extends in the direction of gravity G. The direction of gravity G serving as the second intersecting direction is perpendicular to (intersects with) both the mounting direction AD and the width direction W.

[0046] The second restricting member 152 is configured to be movable between a second restricting position and a second allowable position. In the second restricting position, the support portion 152b of the second restricting member 152 abuts against the pickup arm 113 located at the third holding position, thereby restricting the pickup arm 113 from swinging from the third holding position toward the first holding position. In addition, in the second allowable position, the second restricting member 152 allows the pickup arm 113 to swing from the third holding position toward the first holding position. The second restricting member 152 is biased toward the second restricting position by a spring 156 serving as a second biasing member.

[0047] [Arrangement Relationship Between Second Restriction Member and Each Sensor] Finally, the arrangement relationship between the second restriction member 152, the sheet presence sensor 153, and the arm sensor 154 will be described using Figure 6. As shown in Figure 6, the sheet presence sensor 153, the arm sensor 154, and the second restriction member 152 are roughly aligned in this order in the feeding direction FD in which the pickup roller 110 feeds the sheet S. More specifically, the optical path LP2 of the arm sensor 154 is arranged downstream of the optical path LP1 of the sheet presence sensor 153 in the feeding direction FD. The rotation shaft 155 of the second restriction member 152 is arranged downstream of the optical path LP2 of the arm sensor 154 in the feeding direction FD.

[0048] The sheet presence / absence sensor 153 is positioned so that it at least partially overlaps the second regulating member 152 when viewed in the feeding direction FD, and the arm sensor 154 is positioned so that it does not overlap the sheet presence / absence sensor 153 or the second regulating member 152 when viewed in the feeding direction FD.

[0049] Furthermore, the sheet presence sensor 153 is disposed so as to overlap at least a portion of the arm sensor 154 when viewed in the direction of gravity G, and the second regulating member 152 is disposed so as to overlap at least a portion of the arm sensor 154 when viewed in the direction of gravity G. Furthermore, the sheet presence sensor 153 and the second regulating member 152 are disposed so as not to overlap each other when viewed in the direction of gravity G.

[0050] By arranging the second regulating member 152, the sheet presence sensor 153, and the arm sensor 154 in this manner, the second regulating member 152, the sheet presence sensor 153, and the arm sensor 154 can be arranged compactly. Note that the relative positions of the second regulating member 152, the sheet presence sensor 153, and the arm sensor 154 are not limited to those in this embodiment. [Operation of the first regulating member and the second regulating member when inserting or removing a cassette]

[0051] Next, the operation of the first regulating member 123 and the second regulating member 152 when inserting or removing the cassette 31 into or from the apparatus main body 1A will be described. In the following, it is assumed that the feeding unit 32 is attached to the apparatus main body 1A.

[0052] First, when the cassette 31 is pulled out from the apparatus main body 1A, the first restricting member 123 and the second restricting member 152 are respectively biased by the springs 124 and 156 to be located at the first restricting position and the second restricting position. At this time, the pickup arm 113 is held at the second holding position by the first restricting member 123 located at the first restricting position. The biasing force of the spring 124 that biases the first restricting member 123 is set to be stronger than that of the torsion coil spring 121 that biases the pickup arm 113.

[0053] The pickup roller 110 held by the pickup arm 113 positioned at the second holding position is positioned at the retracted position. In this way, the pickup roller 110 is positioned at the retracted position retracted above the movement path of the cassette 31, so that interference with the pickup roller 110 can be prevented when inserting or removing the cassette 31 into or from the apparatus main body 1A. Also, the number of sheets S that can be stored in the cassette 31 can be increased.

[0054] As the cassette 31 is mounted (inserted) into the storage space SP (see FIG. 2) of the apparatus main body 1A, the first pressing portion 157 provided on the cassette 31 abuts against the pressed portion 123a (see FIG. 5) of the first restricting member 123. The position of the cassette 31 in the mounting direction AD at this time is defined as the first abutment position.

[0055] When the cassette 31 is further moved in the installation direction AD, as shown in FIG. 4 , the first pressing portion 157 presses the pressed portion 123a of the first restricting member 123, causing the first restricting member 123 to rotate in the direction of arrow R1 around the rotation shaft 122 against the biasing force of the spring 124. By rotating in the direction of arrow R1, the first restricting member 123 moves from the first restricting position to the first allowable position. As a result, in accordance with the swinging of the pressing portion 123b of the first restricting member 123, the pickup arm 113 swings from the second holding position to the third holding position and is held at the third holding position by the pressing portion 123b. The pickup arm 113 may also be held at the third holding position by the support portion 152b of the second restricting member 152, which is positioned at the second restricting position (described later). When the pickup arm 113 is positioned at the third holding position, the pickup roller 110 does not come into contact with the uppermost sheet supported by the cassette 31 even when the cassette 31 contains the maximum number of sheets that can be accommodated.

[0056] 4, when the cassette 31 is further moved in the mounting direction AD, the second pressing portion 158 provided on the cassette 31 abuts against the pressed portion 152a of the second restricting member 152. The position of the cassette 31 in the mounting direction AD at this time is referred to as the second abutment position. The second abutment position is a position downstream of the first abutment position in the mounting direction AD.

[0057] When the cassette 31 is further moved in the installation direction AD, the second pressing portion 158 presses the pressed portion 152a of the second restricting member 152, causing the second restricting member 152 to rotate in the direction of arrow R2 about the rotation shaft 155 against the biasing force of the spring 156. By rotating in the direction of arrow R2, the second restricting member 152 moves from the second restricting position to the second allowing position. As a result, in conjunction with the swinging of the support portion 152b of the second restricting member 152, the biasing force of the torsion coil spring 121 causes the pickup arm 113 to swing from the third holding position to the first holding position.

[0058] When second restricting member 152 moves from the second restricting position to the second allowing position, support portion 152b of second restricting member 152 moves away from, for example, arm flag 113b of pickup arm 113. This releases the restriction on downward swing of pickup arm 113, and pickup arm 113 moves down to the first holding position by the biasing force of torsion coil spring 121 so that pickup roller 110 is positioned at the contact position.

[0059] The second restricting member 152 rotates around a rotation axis 155 extending in the direction of gravity G. Therefore, even if the movement distance in the installation direction AD of the pressed portion 152a pressed by the cassette 31 is small, the support portion 152b can be separated from the pickup arm 113. In other words, the movement distance in the installation direction AD of the cassette 31 for the second restricting member 152 to reach the second permissible position after the cassette 31 abuts against the pressed portion 152a of the second restricting member 152 at the second abutting position can be made small.

[0060] Therefore, by bringing the second abutment position of the cassette 31 and the mounting position as close as possible, the pickup arm 113 can be moved to the first holding position, i.e., the pickup roller 110 can be moved to the abutting position, almost simultaneously with the cassette 31 reaching the mounting position. Therefore, when the cassette 31 is mounted to the mounting position, the topmost sheet stored in the cassette 31 and the pickup roller 110 can be prevented from rubbing against each other in the mounting direction AD, improving the stackability of the sheets S stored in the cassette 31. Furthermore, wear on the pickup roller 110 can be reduced, thereby extending the life of the pickup roller 110. Furthermore, by reducing misalignment of the topmost sheet due to the topmost sheet rubbing against the pickup roller 110, feeding problems can be reduced.

[0061] When cassette 31 is pulled out in the pulling direction DD from the installed position relative to apparatus main body 1A, first restricting member 123 and second restricting member 152 operate in the opposite manner to that described above. That is, when cassette 31 is pulled out in the pulling direction DD from the installed position, second restricting member 152 rotates from the second permissible position to the second restricting position, and first restricting member 123 rotates from the first permissible position to the first restricting position. As a result, pickup roller 110 is pressed upward by pressing portion 123b of first restricting member 123 and swings from the first holding position to the third holding position and then to the second holding position.

[0062] At this time, the pickup roller 110 moves upward immediately after the cassette 31 is pulled out in the pull-out direction DD from the installation position, so that friction between the pickup roller 110 and the uppermost sheet accommodated in the cassette 31 can be suppressed.

[0063] As described above, in this embodiment, the feeding unit 32 is configured to be detachable from the apparatus main body 1A. The pickup roller 110 provided in the feeding unit 32 can be separated from the pickup roller 110 in the pull-out direction DD by gripping the claw portion 110b shown in FIG. 3. Similarly, the conveying roller 111 can be separated from the conveying roller shaft 114 in the pull-out direction DD by gripping the claw portion 111b. The separation roller 112 can be separated from the separation roller shaft (not shown) in the pull-out direction DD by gripping the claw portion 112b.

[0064] In this way, the pickup roller 110, the conveying roller 111, and the separation roller 112 can be replaced with the feeding unit 32 removed from the apparatus main body 1A, thereby improving the maintainability of these rollers, including the pickup roller 110.

[0065] Furthermore, in this embodiment, the second restricting member 152 is provided in the apparatus main body 1A, which includes a guide rail 159 that guides the cassette 31. Reducing the number of parts interposed between the cassette 31 and the second restricting member 152 improves the accuracy of the relative position between the cassette 31 and the second restricting member 152. This improves the accuracy of the timing at which the cassette 31 presses the second restricting member 152 and the pickup arm 113 descends from the third holding position to the first holding position. This reduces friction between the pickup roller 110 and the topmost sheet stored in the cassette 31, thereby reducing wear on the pickup roller 110 and feeding problems.

[0066] Although the first restricting member 123 is provided in the feeding unit 32, even if the first restricting member 123 moves to the first allowable position, the pickup arm 113 is held at the third holding position by the second restricting member 152. When the pickup arm 113 is located at the third holding position, the pickup roller 110 does not contact the uppermost sheet in the cassette 31. Therefore, the relative positional accuracy between the cassette 31 and the first restricting member 123 does not need to be as high as the relative positional accuracy between the cassette 31 and the second restricting member 152. By providing the first restricting member 123 in the feeding unit 32, the maintainability and assembly of the first restricting member 123 and the spring 124 can be improved.

[0067] Furthermore, the second restricting member 152, the sheet presence sensor 153, and the arm sensor 154 are attached to the main body frame 150 of the apparatus main body 1A via the attachment member 151. This improves the ease of assembly and maintenance of the second restricting member 152, the sheet presence sensor 153, and the arm sensor 154, which are disposed in a recessed position in the storage space SP. Furthermore, the second restricting member 152, the sheet presence sensor 153, and the arm sensor 154 can be disposed compactly.

[0068] Other Embodiments In the above-described embodiment, the second restricting member 152 is provided in the apparatus main body 1A, but this is not limiting. For example, the second restricting member 152 may be provided in the feeding unit 32. For example, the second restricting member 152 is supported on the feeding frame 120 of the feeding unit 32 so as to be rotatable about a rotation shaft 155. In this way, by providing both the first restricting member 123 and the second restricting member 152 in the feeding unit 32, it is easier to determine the relative positions of the first restricting member 123 and the second restricting member 152, and assembly can be performed more easily.

[0069] In the above embodiment, the second restricting member 152 is disposed downstream of the first restricting member 123 in the mounting direction AD, but this is not limiting. For example, at least a portion of the first restricting member 123 may be located at the same position (overlapping) as the second restricting member 152 in the mounting direction AD.

[0070] In the above embodiment, the rotation shaft 155 extends in the direction of gravity G. However, this is not essential. For example, the rotation shaft 155 may extend in a direction parallel to the direction of gravity G.

[0071] The present disclosure is applicable to image forming apparatuses such as printers, copiers, facsimiles, and multifunction peripherals having these functions, and in particular to sheet feeding devices including a sheet feeding unit that is detachable from the device body and a sheet support unit that is removable from the device body, and to image forming apparatuses including the sheet feeding device.

[0072] The present disclosure is not limited to the above-described embodiments, and various modifications and variations are possible without departing from the spirit and scope of the present disclosure. Therefore, to apprise the public of the scope of the present disclosure, the following claims are appended.

[0073] This application claims priority based on Japanese Patent Application No. 2024-149806, filed August 30, 2024, the entire contents of which are incorporated herein by reference.

[0074] 1: Image forming apparatus / 1A: Apparatus main body / 30: Sheet feeding device / 31: Sheet support portion (cassette) / 32: Feeding unit / 110: Feeding roller (pickup roller) / 111: Conveying roller / 112: Separation roller / 113: Holding member (pickup arm) / 114: Rotating shaft (conveying roller shaft) / 121: Third biasing member (torsion coil spring) / 122: First rotating shaft (rotating shaft) / 123: First regulating member / 124: First biasing member (spring) / 150: Frame (main body frame) / 151: Mounting member / 152: Second restricting member / 153: First detection unit (sheet presence / absence sensor) / 154: Second detection unit (arm sensor) / 155: Second rotation axis, rotation axis / 156: Second biasing member (spring) / AD: Mounting direction / D1: First intersecting direction (intersecting direction) / DD: Pull-out direction / G: Second intersecting direction, gravity direction / LP1, LP2: Optical path

Claims

1. An apparatus main body; a sheet support section configured to be attachable to the apparatus main body in an attachment direction and to be withdrawable in a withdrawal direction opposite to the attachment direction, and to support sheets; a feeding unit detachable from the apparatus main body, the feeding roller being movable up and down to an abutment position at which it can abut against the uppermost sheet supported by the sheet support section, and a retracted position at which it is retracted above the abutment position so as to be spaced apart from the uppermost sheet; and a holding member supported so as to be swingable and holding the feeding roller rotatably, the holding member being swingable between a first holding position at which it holds the feeding roller at the abutment position, a second holding position at which it holds the feeding roller at the retracted position, and a third holding position between the first holding position and the second holding position. a first restricting member movable to a first restricting position at which the holding member located at the second holding position is brought into contact with the holding member located at the second holding position to restrict the holding member from swinging from the second holding position to the third holding position, and a first allowing position at which the holding member is allowed to swing from the second holding position to the third holding position; and a second restricting member provided on the device body, movable to a second restricting position at which the holding member located at the third holding position is brought into contact with the holding member located at the third holding position to restrict the holding member from swinging from the third holding position to the first holding position, and a second allowing position at which the holding member is allowed to swing from the third holding position to the first holding position, wherein the first restricting member and the second restricting member are respectively positioned at the first restricting position and the second restricting position when the sheet support portion is pulled out from the device body, When the sheet support portion is attached to the apparatus main body to which the feeding unit is attached, the sheet support portion abuts against the first regulating member located at the first regulating position at a first abutting position, and abuts against the second regulating member located at the second regulating position at a second abutting position downstream of the first abutting position in the attachment direction,a sheet feeding device in which, when the sheet support portion is attached to the device main body with the feeding unit attached to the device main body, the first regulating member is pressed against the sheet support portion and moves from the first regulating position to the first allowing position, thereby causing the holding member to swing from the second holding position to the third holding position, and the second regulating member is pressed against the sheet support portion and moves from the second regulating position to the second allowing position, thereby causing the holding member to swing from the third holding position to the first holding position.

2. The sheet feeding device according to claim 1, wherein the second regulating member is disposed downstream of the first regulating member in the mounting direction when the feeding unit is mounted in the device main body.

3. A sheet feeding device as described in claim 1 or 2, further comprising: a first biasing member that biases the first regulating member toward the first regulating position; a second biasing member that biases the second regulating member toward the second regulating position; and a third biasing member that biases the holding member toward the first holding position.

4. A sheet feeding device described in any one of claims 1 to 3, wherein the first regulating member is configured to be rotatable around a first rotation axis between the first regulating position and the first allowable position, and the second regulating member is configured to be rotatable around a second rotation axis different from the first rotation axis between the second regulating position and the second allowable position.

5. A sheet feeding device according to claim 4, wherein the first rotation axis extends in a first intersecting direction that intersects with the mounting direction, and the second rotation axis extends in a second intersecting direction that intersects with both the mounting direction and the first intersecting direction.

6. The sheet feeding device according to claim 5, wherein the second intersecting direction is a direction along the direction of gravity.

7. A sheet feeding device according to any one of claims 1 to 6, wherein the feeding unit has a conveying roller that conveys the sheet fed by the feeding roller and a rotating shaft that rotatably supports the conveying roller, and the holding member is supported on the rotating shaft so that it can swing.

8. The sheet feeding device according to claim 7, wherein the feeding unit has a separation roller that contacts the transport roller and separates the sheets fed by the feed roller one by one together with the transport roller.

9. A sheet feeding device as described in any one of claims 1 to 8, further comprising: a first detection unit provided in the device main body and detecting whether a sheet is supported on the sheet support unit attached to the device main body; and a second detection unit provided in the device main body and detecting the position of the holding member of the feeding unit attached to the device main body.

10. The sheet feeding device according to claim 9, wherein the device main body comprises a frame and a mounting member that supports the second regulating member, the first detection unit, and the second detection unit and is mounted to the frame.

11. A sheet feeding device as described in claim 9 or 10, wherein the first detection unit and the second detection unit are optical sensors each having an optical path, the second regulating member is configured to be rotatable around a rotation axis between the second regulating position and the second permissible position, the optical path of the second detection unit is arranged downstream of the optical path of the first detection unit in the feeding direction in which the feed roller feeds the sheet, and the rotation axis of the second regulating member is arranged downstream of the optical path of the second detection unit in the feeding direction.

12. A sheet feeding device as described in claim 11, wherein the first detection unit is positioned so that it at least partially overlaps the second regulating member when viewed in the feeding direction, and the second detection unit is positioned so that it does not overlap the first detection unit or the second regulating member when viewed in the feeding direction.

13. A sheet feeding device described in any one of claims 9 to 12, wherein the first detection unit is arranged so that at least a portion thereof overlaps with the second detection unit when viewed in the direction of gravity, and the second regulating member is arranged so that at least a portion thereof overlaps with the second detection unit when viewed in the direction of gravity.

14. The sheet feeding device according to claim 13, wherein the first detection section and the second regulating member are arranged so as not to overlap each other when viewed in the direction of gravity.

15. An apparatus main body; a sheet support section configured to be attachable to the apparatus main body in an attachment direction and to be withdrawable in a withdrawal direction opposite to the attachment direction, and to support sheets; a feeding unit detachable from the apparatus main body, the feeding roller being movable up and down to an abutment position at which it can abut against the uppermost sheet supported by the sheet support section, and a retracted position at which it is retracted above the abutment position so as to be spaced apart from the uppermost sheet; and a holding member supported so as to be swingable and holding the feeding roller rotatably, the holding member being swingable between a first holding position at which it holds the feeding roller at the abutment position, a second holding position at which it holds the feeding roller at the retracted position, and a third holding position between the first holding position and the second holding position. a first restricting member movable to a first restricting position, at which the first restricting member abuts against the holding member located at the second holding position to restrict the holding member from swinging from the second holding position to the third holding position, and a first allowing position to allow the holding member to swing from the second holding position to the third holding position; and a second restricting member movable to a second restricting position, at which the first restricting member abuts against the holding member located at the third holding position to restrict the holding member from swinging from the third holding position to the first holding position, and a second allowing position to allow the holding member to swing from the third holding position to the first holding position, wherein the first restricting member and the second restricting member are located at the first restricting position and the second restricting position, respectively, when the sheet support portion is pulled out from the device main body, When the sheet support portion is attached to the apparatus main body to which the feeding unit is attached, the sheet support portion abuts against the first regulating member located at the first regulating position at a first abutting position, and abuts against the second regulating member located at the second regulating position at a second abutting position downstream of the first abutting position in the attachment direction,a sheet feeding device in which, when the sheet support portion is attached to the device main body with the feeding unit attached to the device main body, the first regulating member is pressed against the sheet support portion and moves from the first regulating position to the first allowing position, thereby causing the holding member to swing from the second holding position to the third holding position, and the second regulating member is pressed against the sheet support portion and moves from the second regulating position to the second allowing position, thereby causing the holding member to swing from the third holding position to the first holding position.

16. An image forming apparatus comprising: a sheet feeding device according to any one of claims 1 to 15; and an image forming section that forms an image on a sheet fed from the sheet feeding device.

Images