Sheet feeding device and image forming apparatus

Abstract

This improves the maintainability of the feed rollers. [Solution] The device comprises a main body, a sheet support section, a feeding unit detachable from the main body, the feeding unit having a feeding roller, a holding member that is pivotably supported and rotatably holds the feeding roller, and a first regulating member, and a second regulating member provided on the main body. When the sheet support section is attached to the main body with the feeding unit attached, the first regulating member is pressed by the sheet support section and moves from the first regulating position to the first allowable position, causing it to pivot from the second holding position to the third holding position, and the second regulating member is pressed by the sheet support section and moves from the second regulating position to the second allowable position, causing it to pivot from the third holding position to the first holding position.

Description

Technical Field

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

Background Art

[0002] Conventionally, an image forming apparatus has been proposed that includes a paper feed cassette that is provided so as to be pullable out with respect to a device main body and that stores sheets, and a paper feed unit that is provided in the device main body and feeds the sheets stored in the paper feed cassette (see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the paper feed unit described in Patent Document 1 is provided at a deep position in the device main body, and there is a problem in maintainability when replacing rollers such as a pickup roller, a pickup roller, and a retard roller provided in the paper feed unit.

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

Means for Solving the Problems

[0006] One aspect of the present invention comprises a device body, a sheet support portion configured to be attachable to the device body in the mounting direction and extendable in the extension direction opposite to the mounting direction, and supporting a sheet, a feeding unit detachable from the device body, comprising a feeding roller that is movable up and down between a contact position that can contact the uppermost sheet supported by the sheet support portion and a retracted position that is retracted above the contact position so as to be separated from the uppermost sheet, and a holding member that is swingably supported and rotatably holds the feeding roller, wherein the feeding roller is supported by the contact A feeding unit having a holding member that is pivotable to a first holding position that holds the feeding roller in a position, a second holding position that holds the feeding roller in the retracted position, and a third holding position between the first holding position and the second holding position, a first restricting position that is movable to a first restricting position that abuts the holding member located at the second holding position and restricts the holding member from pivoting from the second holding position toward the third holding position, and a first allowing position that allows the holding member to pivot from the second holding position toward the third holding position, and provided on the main body of the device, The device includes a second restricting member that is movable to the retaining member located in the third retaining position and restricts the retaining member from swinging from the third retaining position toward the first retaining position, and a second allowing position that permits the retaining member to swing from the third retaining position toward the first retaining position, wherein the first restricting member and the second restricting member are located in the first restricting position and the second restricting position, respectively, when the seat support is pulled out from the device body, and the seat support is located in the device body to which the feeding unit is attached. When installed, the holding member abuts against the first restricting member located at the first restricting position at the first abutment position, and abuts against the second restricting member located at the second restricting position at the second abutment position downstream of the first abutment position in the installation direction, and when the sheet support portion is installed on the device body with the feeding unit installed on the device body, the first restricting member is pressed against the sheet support portion and moves from the first restricting position to the first allowable position, causing the holding member to swing from the second holding position to the third holding position.The sheet feeding device is characterized in that the second regulating member is pressed against the sheet support portion and moves from the second regulating position to the second allowable position, thereby swinging from the third holding position to the first holding position.

[0007] Another aspect of the present invention comprises a device body, a sheet support portion configured to be attachable to the device body in the mounting direction and extendable in the extension direction opposite to the mounting direction, and supporting a sheet, a feeding unit detachable from the device body, comprising a feeding roller that is movable up and down between a contact position that can contact the uppermost sheet supported by the sheet support portion and a retracted position that is retracted above the contact position so as to be separated from the uppermost sheet, and a holding member that is swingably supported and rotatably holds the feeding roller, wherein the feeding roller A holding member that can swing between a first holding position that holds the feed roller in the contact position, a second holding position that holds the feed roller in the retracted position, and a third holding position between the first and second holding positions; a first restricting position that is movable to the holding member located at the second holding position and restricts the holding member from swinging from the second holding position toward the third holding position, and a first allowing position that allows the holding member to swing from the second holding position toward the third holding position; and the holding part located at the third holding position A feeding unit having a second restricting member that is movable to a second restricting position which contacts the material and restricts the holding member from swinging from the third holding position toward the first holding position, and a second allowable position which allows the holding member to swing from the third holding position toward 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 is pulled out from the main body of the device, the sheet support 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 mounting direction, and the holding member swings from the second holding position toward the third holding position when the sheet support is mounted to the main body of the device with the feeding unit mounted to the main body of the device, as the first restricting member is pressed against the sheet support and moves from the first restricting position toward the first allowable position,The sheet feeding device is characterized in that the second regulating member is pressed against the sheet support portion and moves from the second regulating position to the second allowable position, thereby swinging from the third holding position to the first holding position. [Effects of the Invention]

[0008] According to the present invention, the maintainability of the feed roller can be improved. [Brief explanation of the drawing]

[0009] [Figure 1] A schematic diagram showing the image forming apparatus according to this embodiment. [Figure 2] A perspective view showing the feeding unit in a state where it has been pulled out from the main body of the device. [Figure 3] A perspective view showing the feeding unit. [Figure 4] A perspective view showing the feeding unit attached to the main body of the device. [Figure 5] A perspective view showing the feeding unit and cassette when they are mounted on the main body of the device. [Figure 6] A perspective view showing the second restricting member and its surrounding components in the state where the cassette has been pulled out. [Modes for carrying out the invention]

[0010] [Overall structure] The image forming apparatus 1 according to this embodiment is an electrophotographic laser beam printer, and as shown in Figure 1, it has an image forming unit 10 for forming an image on a sheet S, a fixing unit 20, sheet feeding devices 30, 130, 230, and a sheet support device 40.

[0011] Furthermore, an image forming apparatus includes printers, copiers, facsimile machines, and multifunction devices, and refers to a device that forms images on a sheet used as a recording medium based on image information input from an external PC or image information read from a document. In addition to the main unit with image forming functions, an image forming apparatus may also include auxiliary equipment such as optional feeders, image readers, and sheet processing devices, and the entire system with such auxiliary equipment connected is also a type of image forming apparatus.

[0012] The image forming unit 10 comprises four process cartridges 11Y, 11M, 11C, and 11Bk, each forming 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 color of the image they form. Therefore, only the configuration and image forming process of process cartridge 11Y will be described, and the descriptions of process cartridges 11M, 11C, and 11Bk will be omitted.

[0013] The process cartridge 11Y includes a photosensitive drum 12, a charging roller 13, and a developing roller 14. The photosensitive drum 12 is constructed by coating the outer circumference of an aluminum cylinder with an organic photoconductive layer and is rotated by a drive motor (not shown). The image forming unit 10 is also provided with an intermediate transfer belt 18 wrapped 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.

[0014] The fixing unit 20 includes a fixing film 21 heated by a heater (not shown) and a pressure roller 22 that presses against the fixing film 21. The sheet feeding devices 30, 130, 230 are located at the bottom of the image forming apparatus 1 and include cassettes 31, 131, 231 for storing sheets and feeding units 32, 132, 232 for feeding sheets.

[0015] Next, the image forming operation of the image forming apparatus 1 configured as described above will be explained. When an image signal is input from a personal computer or the like (not shown) to the scanner unit 15, laser light corresponding to the image signal is irradiated onto the photosensitive drum 12 of the process cartridge 11Y from the scanner unit 15.

[0016] At this time, the surface of the photosensitive drum 12 is uniformly charged to a predetermined polarity and potential in advance by the charging roller 13, and an electrostatic latent image is formed on the surface when laser light is irradiated 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.

[0017] Similarly, laser light is irradiated from the scanner unit 15 onto each photosensitive drum of the process cartridges 11M, 11C, and 11Bk, and magenta (M), cyan (C), and black (Bk) toner images are formed on each photosensitive drum. The toner images of each color formed on each photosensitive drum are transferred to the intermediate transfer belt 18 by the primary transfer rollers 19Y, 19M, 19C, and 19Bk, and are conveyed to the secondary transfer roller 25 by the intermediate transfer belt 18 that is rotated by the drive roller 16. Note that each color image forming process is performed at a timing to overlap with the upstream toner image that has been primarily transferred onto the intermediate transfer belt 18.

[0018] In parallel with this image forming process, the sheet S is fed from any one of the sheet feeding devices 30, 130, and 230. Since the sheet feeding devices 30, 130, and 230 have the same configuration, hereinafter, the case where the sheet S is fed from the sheet feeding device 30 will be described as an example. Note that the cassettes 31, 131, and 231 may accommodate sheets of different sizes.

[0019] The sheet S housed in the cassette 31 of the sheet feeding device 30 is fed out by the feeding unit 32 and then conveyed to the registration roller pair 35. The sheet S whose skew is corrected by the registration roller pair 35 is conveyed to the main conveyance path 43 at a predetermined conveyance timing. Then, a full-color toner image on the intermediate transfer belt 18 is transferred onto the sheet S by the secondary transfer bias applied to the secondary transfer roller 25.

[0020] The sheet S onto which the toner image has been transferred is given predetermined heat and pressure by the fixing film 21 and the pressure roller 22 of the fixing unit 20, and the toner is melted and fixed (fixed). The sheet S that has passed through the fixing unit 20 is discharged to the discharge tray 27 by the discharge roller pair 26.

[0021] When performing double-sided printing in which images are formed on both sides of the sheet S, the sheet S on which an image has been formed on the first side is conveyed toward the double-sided conveyance path 41 by reversing the discharge roller pair 26. The sheet S is conveyed by the double-sided conveyance roller pair 42 provided in the double-sided conveyance path 41 and merges into the main conveyance path 43. Then, the toner image on the intermediate transfer belt 18 is transferred onto the second side of the sheet S opposite to the first side, and the sheet S is discharged to the discharge tray 27 by the discharge roller pair 26.

[0022] The image forming apparatus 1 also has a main body 1A, and a sheet support device 40 is supported on the main body 1A so as to be openable and closable. The cassettes 31, 131, and 231 described above are configured to be mountable on the main body 1A in the mounting direction AD described later and to be pullable out in the pulling direction DD (see Figure 2). The sheet support device 40 has a main body 50, a transfer unit 60, and a sheet support unit 70. The sheet support unit 70 is configured to be rotatable on a pivot axis 71 relative to the main body 50 and can support a sheet when open relative to the main body 50. The sheet supported by the sheet support unit 70 can be fed by a pickup roller (not shown), and the fed sheet joins the main transport path 43. The main body 50 is supported on the main body 1A so as to be openable and closable on a pivot axis 51. The transfer unit 60 is supported on the main body 50 so as to be openable and closable on a pivot axis 61 and supports a secondary transfer roller 25, etc.

[0023] A main transport path 43 is formed between the main body 1A and the transfer unit 60. When the transfer unit 60 is opened relative to the main body 1A along with the main body 50, the main transport path 43 is opened. In this state, when the transfer unit 60 is opened relative to the main body 50, the double-sided transport path 41 between the main body 50 and the transfer unit 60 is opened. By configuring the main transport path 43 and the double-sided transport path 41 to be openable in this way, jam handling performance can be improved.

[0024] [Feeding Unit] Next, the feeding unit 32 will be described using Figures 1 to 5. Note that the feeding units 132 and 232 described above have the same configuration as the feeding unit 32, so their description will be omitted. Figure 2 is a perspective view showing the feeding unit 32 pulled out from the main body 1A. Figure 3 is a perspective view showing the feeding unit 32. Figure 4 is a perspective view showing the feeding unit 32 mounted on the main body 1A. Figure 5 is a perspective view showing the feeding unit 32 when the feeding unit 32 and cassette 31 are mounted on the main body 1A. Note that in Figure 4, the cassette 31 is in the mounting position mounted on the main body 1A, and with the cassette 31 in the mounting position, the image forming apparatus 1 can execute the image forming process.

[0025] As shown in Figures 1 to 4, the feeding unit 32 is configured to be mountable on the main body 1A in the mounting direction AD and to be pullable out in the pulling direction DD opposite to the mounting direction AD. The feeding unit 32 has a pickup roller 110 as a feeding roller for feeding the sheets S contained in the cassette 31, and a transport roller 111 for transporting the sheets S fed by the pickup roller 110. The feeding unit 32 also has a separation roller 112 that contacts the transport roller 111 and separates the sheets S one by one together with the transport roller 111, and a pickup arm 113 as a holding member that rotatably holds the pickup roller 110.

[0026] Furthermore, the feeding unit 32 includes a feeding frame 120 and a conveyor roller shaft 114 that is rotatably supported by the feeding frame 120 and rotatably supports the conveyor rollers 111. The conveyor roller shaft 114, as a rotating shaft, engages with a coupling 115 provided on the device body 1A when the feeding unit 32 is mounted on the device body 1A. As a result, drive is transmitted to the conveyor roller shaft 114 from the coupling 115. A conveyor roller gear 116 is fixed to the conveyor roller shaft 114.

[0027] The pickup arm 113 is pivotably supported on the conveyor 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 conveyor roller gear 116 and the pickup gear 117.

[0028] The rotation of the conveyor roller gear 116, which rotates together with the conveyor roller shaft 114, is transmitted to the pickup gear 117 via the idler gear 118. As the pickup gear 117 rotates, the pickup roller shaft 110a and the pickup roller 110 rotate. The separation roller 112 is pressed against the conveyor roller 111 with a predetermined contact pressure and rotates in accordance with the conveyor roller 111. In this way, the drive transmitted from the main body 1A to the conveyor roller shaft 114 causes the pickup roller 110, the conveyor roller 111, and the separation roller 112 to rotate.

[0029] Furthermore, the separation roller 112 has a built-in torque limiter, so if multiple sheets S enter the separation nip between the conveyor roller 111 and the separation roller 112, the separation roller 112 will not rotate in accordance with the conveyor roller 111. On the other hand, if only one sheet S enters the separation nip, the separation roller 112 will rotate in accordance with the conveyor roller 111 via the sheet S. In addition, the separation roller 112 may be driven to rotate in the direction that returns the sheet S toward the cassette 31.

[0030] As shown in Figure 4, the coil portion 121a of a torsion coil spring 121, which serves as a third biasing member, is mounted on the conveyor roller shaft 114. The torsion coil spring 121 has a first locking portion 121b extending from the coil portion 121a to one side, and a second locking portion 121b extending from the coil portion 120a to the other side. 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 around the conveyor roller shaft 114.

[0031] Here, the pickup roller 110 can move up and down between a contact position where it can contact the uppermost sheet supported by the cassette 31, and a retracted position where it is retracted above the contact position so as to be separated from the uppermost sheet, by the swinging of the pickup arm 113. The pickup arm 113 is configured to swing between a first holding position (shown in Figure 1) where it holds the pickup roller 110 in the contact position, and a second holding position (shown in Figure 5) where it holds the pickup roller 110 in the retracted position. The position between the first and second holding positions will be referred to as the third holding position, which will be described in more detail later. The torsion coil spring 121 described above biases the pickup arm 113 toward the first holding position.

[0032] Furthermore, as shown in Figures 2 to 5, the feeding unit 32 includes a first restricting member 123 that is rotatably supported on the feeding frame 120 around a pivot axis 122, and a spring 124 as a first biasing member that biases the first restricting member 123. The pivot axis 122, as the first pivot axis, extends in a first intersecting direction D1 that intersects the mounting direction AD and the withdrawal direction DD. This intersecting direction D1 is parallel to the horizontal direction and is in line with the feeding direction FD in which the pickup roller 110 feeds the sheet S. The first restricting member 123 has a pressed portion 123a and a pressing portion 123b. The pressed portion 123a is pressed against the cassette 31, as will be described later. The pressing portion 123b presses against the contact portion 113a of the pickup arm 113, thereby causing the pickup arm 113 to swing toward the second holding position.

[0033] The first restricting member 123 is configured to be movable between a first restricting position and a first allowable position. At the first restricting position, the first restricting member 123 has a pressing portion 123b that contacts the pickup arm 113 located at the second holding position, restricting the pickup arm 113 from swinging from the second holding position to the third holding position. At the first allowable position, the first restricting member 123 allows the pickup arm 113 to swing from the second holding position to the third holding position.

[0034] When the first regulating member 123 moves from the first regulating position to the first allowable position, the pressing portion 123b descends, and as a result, the pickup arm 113 also moves from the second holding position to the third holding position. Conversely, when the first regulating member 123 moves from the first allowable position to the first regulating position, the pressing portion 123b presses against the contact portion 113a of the pickup arm 113, pushing the pickup arm 113 up from the third holding position to the second holding position. The spring 124 is stretched between the feed frame 120 and the first regulating member 123, biasing the first regulating member 123 toward the first regulating position.

[0035] 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 seat presence / absence flag 125 that is swingably supported by the feeding frame 120.

[0036] [Second regulatory component] Next, the second restricting member 152 and its surrounding configuration will be described using Figures 2 to 6. Figure 6 is a perspective view showing the second restricting member 152 and its surrounding configuration in the state where the cassette 31 has been pulled out.

[0037] As shown in Figure 2, the main body of the device 1A has a storage space SP in which the cassette 31 and the feeding unit 32 are housed. As shown in Figure 6, the main body of the device 1A has a main frame 150 as a frame provided at the rear of the storage space SP in the mounting direction AD, and a mounting member 151 attached to the main frame 150. The main body of the device 1A also has a guide rail 159 fixed to the main frame 150 that guides the cassette 31 in the mounting direction AD and the withdrawal direction. The mounting member 151 supports a second regulating member 152, a seat presence sensor 153 as a first detection unit, and an arm sensor 154 as a second detection unit.

[0038] The sheet presence sensor 153 and the arm sensor 154 are optical sensors, each having a light-emitting part and a light-receiving part, and an optical path is formed between these light-emitting and light-receiving parts. 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 contacts the uppermost sheet housed in the cassette 31 from above when the cassette 31 and the feeding unit 32 are mounted on the device body 1A. The sheet presence flag 125 is configured to swing so that it is always in contact with the uppermost sheet housed in the cassette 31 due to its own weight.

[0039] The loading plate 31a (see Figure 1) on which the sheets S are loaded has an opening (not shown), and when no sheets S are placed on the loading plate 31a, the sheet presence / absence flag 125 is positioned in a lower position that enters the opening. The loading plate 31a is supported so as to be able to be raised and lowered by the drive of the lift plate 31b, and is configured to rise as the amount of sheets S loaded on the loading plate 31a decreases when the cassette 31 and the feeding unit 32 are attached to the main body 1A of the device. This makes it possible to keep the paper surface position of the uppermost sheet loaded on the loading plate 31a approximately constant, and allows the sheet S to be fed by the pickup roller 110 with appropriate feeding pressure.

[0040] When at least one sheet S is contained in the cassette 31, which serves as the sheet support, the optical path LP1 of the sheet presence sensor 153 is blocked by the sheet presence flag 125, and the sheet presence sensor 153 is OFF. When there are no more sheets in the cassette 31, the sheet presence flag 125 moves to a lower position, and the optical path LP1 of the sheet presence sensor 153 is no longer blocked. As a result, the sheet presence sensor 153 turns ON, and it can detect that there are no more sheets in the cassette 31. In other words, the sheet presence sensor 153 can detect whether or not there are sheets supported in the cassette 31.

[0041] Furthermore, the arm sensor 154 can detect the arm flag 113b, which swings in conjunction with the pickup arm 113. For example, when an image forming job is input to form an image on a sheet S, the lift plate 31b described above is driven, and the loading plate 31a rises. As a result, the uppermost sheet S loaded on the loading plate 31a comes into contact with the pickup roller 110, which is located at the contact position. The loading plate 31a stops at a position where the uppermost sheet S has come into contact with the pickup roller 110 and the pickup roller 110 has been pushed slightly further upward; the position of the pickup roller 110 at this time is also considered the contact position.

[0042] As the sheets S stored in the cassette 31 are fed along with the image forming job, the paper position of the top sheet on the stacking plate 31a descends. The pickup arm 113 is biased to swing downward by the torsion coil spring 121, so the pickup arm 113 swings downward in conjunction with the descending of the paper position of the top sheet. When the pickup arm 113 exceeds a predetermined position, the arm flag 113b provided on the pickup arm 113 retracts from the optical path LP2 of the arm sensor 154, and the optical path LP2 is no longer blocked. As a result, the arm sensor 154 turns ON. In other words, the arm sensor 154 detects the position of the pickup arm 113.

[0043] 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 loading plate 31a rises by a predetermined amount, and the light path LP2 of the arm sensor 154 is blocked again 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 loading plate 31a rises by a predetermined amount. Thus, although the arm sensor 154 detects the position of the pickup arm 113, it can also be said that it detects the position of the paper surface of the topmost sheet loaded on the loading plate 31a.

[0044] As shown in Figures 4 and 6, the second restricting member 152 is positioned 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 the pivot axis 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 in the third holding position. The pivot axis 155, as the second pivot axis, differs from the pivot axis 122 of the first restricting member 123 in that it extends in the direction of gravity G. The direction of gravity G, as the second intersecting direction, is perpendicular (intersects) both the mounting direction AD and the width direction W.

[0045] 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 in the third holding position, restricting the pickup arm 113 from swinging from the third holding position toward the first holding position. 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, which acts as a second biasing member.

[0046] [Placement relationship between the second regulating member and each sensor] Finally, using Figure 6, the arrangement of the second regulating member 152, the sheet presence sensor 153, and the arm sensor 154 will be explained. As shown in Figure 6, the sheet presence sensor 153, the arm sensor 154, and the second regulating member 152 are roughly arranged in this order in the feeding direction FD when the pickup roller 110 feeds the sheet S. More specifically, the optical path LP2 of the arm sensor 154 is located downstream of the optical path LP1 of the sheet presence sensor 153 in the feeding direction FD. The pivot axis 155 of the second regulating member 152 is located downstream of the optical path LP2 of the arm sensor 154 in the feeding direction FD.

[0047] The sheet presence sensor 153 is positioned such that, when viewed in the feeding direction FD, at least a portion of it overlaps with the second regulating member 152, while the arm sensor 154 is positioned such that, when viewed in the feeding direction FD, it does not overlap with the sheet presence sensor 153 or the second regulating member 152.

[0048] Furthermore, the sheet presence sensor 153 is positioned such that at least a portion of it overlaps with the arm sensor 154 when viewed in the direction of gravity G, and the second regulating member 152 is positioned such that at least a portion of it overlaps with the arm sensor 154 when viewed in the direction of gravity G. Moreover, the sheet presence sensor 153 and the second regulating member 152 are positioned so that they do not overlap each other when viewed in the direction of gravity G.

[0049] By arranging the second restricting member 152, the sheet presence sensor 153, and the arm sensor 154 in this manner, the second restricting member 152, the sheet presence sensor 153, and the arm sensor 154 can be arranged compactly. Note that the arrangement of the second restricting member 152, the sheet presence sensor 153, and the arm sensor 154 is not limited to the arrangement in this embodiment. [Operation of the first and second restricting members when inserting or removing a cassette]

[0050] Next, the operation of the first restricting member 123 and the second restricting member 152 when inserting or removing the cassette 31 from the device body 1A will be described. In the following, it is assumed that the feeding unit 32 is installed in the device body 1A.

[0051] First, when the cassette 31 is pulled out from the main body 1A, the first restricting member 123 and the second restricting member 152 are positioned in the first restricting position and the second restricting position, respectively, due to the biasing force of springs 124 and 156. At this time, the pickup arm 113 is held in the second holding position by the first restricting member 123, which is positioned in the first restricting position. The spring 124 that biases the first restricting member 123 is set to have a stronger biasing force than the torsion coil spring 121 that biases the pickup arm 113.

[0052] Furthermore, the pickup roller 110, which is held by the pickup arm 113 located in the second holding position, is in a retracted position. In this way, since the pickup roller 110 is in a retracted position that is moved upward from the movement trajectory of the cassette 31, interference with the pickup roller 110 can be prevented when inserting or removing the cassette 31 from the device body 1A. In addition, the number of sheets S that can be stored in the cassette 31 can be increased.

[0053] As the cassette 31 is mounted (inserted) into the housing space SP (see Figure 2) of the main body 1A of the device, the first pressing portion 157 provided on the cassette 31 abuts against the pressed portion 123a (see Figure 5) of the first regulating member 123. The position of the cassette 31 in the mounting direction AD at this time is defined as the first abutment position.

[0054] As the cassette 31 is moved further in the mounting direction AD, as shown in Figure 4, the first pressing portion 157 presses against 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 pivot axis 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, the pickup arm 113 swings from the second holding position to the third holding position in conjunction with the swinging of the pressing portion 123b of the first restricting member 123, and is held in the third holding position by the pressing portion 123b. The pickup arm 113 may also be held in the third holding position by the support portion 152b of the second restricting member 152, which is located in the second restricting position, as will be described later. When the pickup arm 113 is in 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 maximum number of sheets that can be accommodated are stored in the cassette 31.

[0055] Then, when the cassette 31 is moved further in the mounting direction AD, as shown in Figure 4, the second pressing portion 158 provided on the cassette 31 abuts against the pressed portion 123a (see Figure 5) of the first regulating member 123. The position of the cassette 31 in the mounting direction AD at this time is defined as the second abutment position. The second abutment position is located downstream in the mounting direction AD from the first abutment position described above.

[0056] As the cassette 31 is moved further in the mounting direction AD, the second pressing portion 158 presses against the pressed portion 152a of the second restricting member 152, causing the second restricting member 152 to rotate in the direction of arrow R2 around the pivot axis 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 allowable position. As a result of the swinging of the support portion 152b of the second restricting member 152, the pickup arm 113 swings from the third holding position to the first holding position due to the biasing force of the torsion coil spring 121.

[0057] The support portion 152b of the second restricting member 152 moves away from the arm flag 113b of the pickup arm 113, for example, when the second restricting member 152 moves from the second restricting position to the second allowable position. This releases the restriction on the downward swing of the pickup arm 113, and the pickup arm 113 descends to the first holding position by the biasing force of the torsion coil spring 121 so that the pickup roller 110 is in contact with the position.

[0058] The second restricting member 152 rotates around a pivot axis 155 that extends along the direction of gravity G. Therefore, even if the distance traveled by the pressed portion 152a in the mounting direction AD by the cassette 31 is small, the support portion 152b can be separated from the pickup arm 113. In other words, the distance traveled by the cassette 31 in the mounting direction AD from the time the cassette 31 abuts against the pressed portion 152a of the second restricting member 152 at the second abutment position until the second restricting member 152 reaches the second allowable position can be reduced.

[0059] Therefore, by bringing the second abutment position and the mounting position of the cassette 31 as close as possible, the pickup arm 113 can be moved to the first holding position, i.e., the contact position of the pickup roller 110, almost simultaneously with the cassette 31 reaching the mounting position. Thus, when mounting the cassette 31 to the mounting position, friction between the top sheet housed in the cassette 31 and the pickup roller 110 in the mounting direction AD can be suppressed, improving the load capacity of the sheet S housed in the cassette 31. Furthermore, wear of the pickup roller 110 can be suppressed, extending the lifespan of the pickup roller 110. In addition, by reducing the displacement of the top sheet caused by friction between the top sheet and the pickup roller 110, feeding failures can be suppressed.

[0060] When the cassette 31 is pulled out from the mounting position to the main body 1A in the pulling direction DD, the operation of the first restricting member 123 and the second restricting member 152 is the reverse of that described above. That is, when the cassette 31 is pulled out from the mounting position in the pulling direction DD, the second restricting member 152 rotates from the second allowable position to the second restricting position, and the first restricting member 123 rotates from the first allowable position to the first restricting position. As a result, the pickup roller 110 is pressed upward by the pressing portion 123b of the first restricting member 123 and swings from the first holding position through the third holding position to the second holding position.

[0061] At this time, the pickup roller 110 moves upward immediately after the cassette 31 is pulled out in the DD direction from its mounting position, thus suppressing friction between the pickup roller 110 and the uppermost sheet housed in the cassette 31.

[0062] As described above, in this embodiment, the feeding unit 32 is configured to be detachable from the main body 1A of the device. The pickup roller 110 provided on the feeding unit 32 can be detached from the pickup roller 110 in the pulling direction DD by gripping the claw portion 110b shown in Figure 3. Similarly, the transport roller 111 can be detached from the transport roller shaft 114 in the pulling direction DD by gripping the claw portion 111b. The separation roller 112 can be detached from the separation roller shaft (not shown) in the pulling direction DD by gripping the claw portion 112b.

[0063] In this way, since the pickup roller 110, conveying roller 111, and separation roller 112 can be replaced with the feeding unit 32 removed from the main body 1A, the maintainability of these rollers, including the pickup roller 110, can be improved.

[0064] Furthermore, in this embodiment, the second restricting member 152 is provided on the device body 1A, which includes a guide rail 159 that guides the cassette 31. By reducing the number of parts interposed between the cassette 31 and the second restricting member 152, the relative positional accuracy between the cassette 31 and the second restricting member 152 can be improved. As a result, the accuracy of the timing in which the cassette 31 presses against the second restricting member 152 and the pickup arm 113 descends from the third holding position to the first holding position can be improved. Therefore, friction between the pickup roller 110 and the uppermost sheet housed in the cassette 31 can be suppressed, and wear of the pickup roller 110 and feeding failures can be suppressed.

[0065] Although the first regulating member 123 is provided in the feeding unit 32, even if the first regulating member 123 moves to the first allowable position, the pickup arm 113 is held in the third holding position by the second regulating member 152. When the pickup arm 113 is in the third holding position, the pickup roller 110 does not come into contact with the uppermost sheet in the cassette 31. Therefore, the relative positional accuracy between the cassette 31 and the first regulating member 123 is not as important as the relative positional accuracy between the cassette 31 and the second regulating member 152. By providing the first regulating member 123 in the feeding unit 32, the maintainability and ease of assembly of the first regulating member 123 and the spring 124 can be improved.

[0066] Furthermore, the second restricting member 152, the seat presence sensor 153, and the arm sensor 154 are attached to the frame 150 of the device body 1A via the mounting member 151. This improves the ease of assembly and maintenance of the second restricting member 152, the seat presence sensor 153, and the arm sensor 154, which are located in recessed positions within the storage space SP. In addition, the second restricting member 152, the seat presence sensor 153, and the arm sensor 154 can be arranged compactly.

[0067] <Other Embodiments> In the above-described embodiment, the second restricting member 152 was provided on the main body 1A of the device, but it is not limited to this. For example, the second restricting member 152 may be provided on the feeding unit 32. For example, the second restricting member 152 may be supported on the feeding frame 120 of the feeding unit 32 so as to be rotatable about a pivot axis 155. By providing both the first restricting member 123 and the second restricting member 152 on the feeding unit 32 in this way, it is easier to determine the relative positions of the first restricting member 123 and the second restricting member 152, and assembly can be improved.

[0068] Furthermore, in the above-described embodiment, the second restricting member 152 was positioned downstream of the first restricting member 123 in the mounting direction AD, but the invention is not limited to this. For example, at least a portion of the first restricting member 123 may be positioned at the same (overlapping) position as the second restricting member 152 in the mounting direction AD.

[0069] Furthermore, in the above-described embodiment, the pivot shaft 155 extended in the direction of gravity G, but this is not limited to this. For example, the pivot shaft 155 may extend in a direction along the direction of gravity G. [Explanation of symbols]

[0070] 1: Image forming apparatus / 1A: Apparatus body / 30: Sheet feeding device / 31: Sheet support part (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 rotation shaft (rotating shaft) / 123: First regulating member / 124: First biasing member (spring) / 150: Frame (main frame) / 151: Mounting member / 152: Second regulating member / 153: First detection unit (seat presence / absence sensor) / 154: Second detection unit (arm sensor) / 155: Second rotation axis, rotation axis / 156: Second biasing member (spring) / AD: Pull-out direction / D1: First crossing direction (crossing direction) / DD: Mounting direction / G: Second crossing direction, gravity direction / LP1,LP2: Optical path

Claims

1. The main body of the device, A sheet support portion is configured to be attachable to the main body of the device in the attachment direction and extendable in the extension direction opposite to the attachment direction, and supports the sheet. A feeding unit that is detachable from the main body of the device, A feeding roller that can move up and down between a contact position that can contact the uppermost sheet supported by the sheet support and a retracted position that is moved upward from the contact position so as to be separated from the uppermost sheet, A holding member that is pivotably supported and rotatably holds the feed roller, the holding member pivotably between a first holding position that holds the feed roller in the contact position, a second holding position that holds the feed roller in the retracted position, and a third holding position between the first and second holding positions. A first restricting member is movable between a first restricting position that contacts the retaining member located at the second retaining position and restricts the retaining member from swinging from the second retaining position toward the third retaining position, and a first allowable position that allows the retaining member to swing from the second retaining position toward the third retaining position. A feeding unit having, A second restricting member is provided on the main body of the device and is movable to a second restricting position which contacts the retaining member located at the third retaining position and restricts the retaining member from swinging from the third retaining position toward the first retaining position, and to a second allowable position which allows the retaining member to swing from the third retaining position toward the first retaining position, Equipped with, The first restricting member and the second restricting member are positioned in the first restricting position and the second restricting position, respectively, when the seat support portion is pulled out from the main body of the device. When the sheet support portion is mounted on the device body to which the feeding unit is attached, it abuts against the first restricting member located at the first restricting position at the first abutment position, and abuts against the second restricting member located at the second restricting position at the second abutment position downstream of the first abutment position in the mounting direction. When the feeding unit is mounted on the main body of the device and the sheet support is mounted on the main body of the device, the holding member swings from the second holding position to the third holding position as the first regulating member is pressed by the sheet support and moves from the first regulating position to the first allowable position, and the holding member swings from the third holding position to the first holding position as the second regulating member is pressed by the sheet support and moves from the second regulating position to the second allowable position. A sheet feeding device characterized by the following features.

2. The second restricting member is positioned downstream of the first restricting member in the mounting direction when the feeding unit is mounted on the main body of the device. The sheet feeding device according to feature 1.

3. 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, The system further comprises a third biasing member that biases the holding member toward the first holding position. The sheet feeding device according to feature 1.

4. The first regulating member is configured to be rotatable about a first pivot axis between the first regulating position and the first allowable position. The second restricting member is configured to be rotatable between the second restricting position and the second allowable position, around a second pivot axis different from the first pivot axis. The sheet feeding device according to feature 1.

5. The first pivot shaft extends in a first intersecting direction that intersects the mounting direction, The second pivot axis extends in a second intersecting direction that intersects both the mounting direction and the first intersecting direction. The sheet feeding device according to feature 4.

6. The second intersecting direction is the direction along the direction of gravity. The sheet feeding device according to feature 5.

7. The feeding unit includes a conveying roller for conveying the sheet fed by the feeding roller, and a rotating shaft that rotatably supports the conveying roller. The holding member is pivotably supported on the rotation shaft. The sheet feeding device according to feature 1.

8. The feeding unit has a separation roller that contacts the conveying roller and separates the sheets fed by the feeding roller into individual sheets together with the conveying roller. The sheet feeding device according to feature 7.

9. A first detection unit is provided on the main body of the device and detects whether or not the sheet is supported by the sheet support portion attached to the main body of the device, The device further comprises a second detection unit provided on the main body of the device for detecting the position of the holding member of the feeding unit mounted on the main body of the device, The sheet feeding device according to feature 1.

10. The device 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 attached to the frame. The sheet feeding device according to feature 9.

11. The first detection unit and the second detection unit are each optical sensors having an optical path, The second restricting member is configured to be rotatable about a pivot axis between the second restricting position and the second allowable position. The optical path of the second detection unit is positioned downstream of the optical path of the first detection unit in the feeding direction in which the feeding roller feeds the sheet. The pivot axis of the second regulating member is positioned downstream of the optical path of the second detection unit in the feeding direction. The sheet feeding device according to feature 9.

12. The first detection unit is positioned such that, when viewed in the feeding direction, at least a portion of it overlaps with the second regulating member. The second detection unit is positioned such that it does not overlap with the first detection unit and the second regulating member when viewed in the feeding direction. The sheet feeding device according to feature 11.

13. The first detection unit is arranged such that, when viewed in the direction of gravity, at least a portion of it overlaps with the second detection unit. The second regulating member is positioned such that, when viewed in the direction of gravity, at least a portion of it overlaps the second detection portion. The sheet feeding device according to feature 9.

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

15. The main body of the device, A sheet support portion is configured to be attachable to the main body of the device in the attachment direction and extendable in the extension direction opposite to the attachment direction, and supports the sheet. A feeding unit that is detachable from the main body of the device, A feeding roller that can move up and down between a contact position that can contact the uppermost sheet supported by the sheet support and a retracted position that is moved upward from the contact position so as to be separated from the uppermost sheet, A holding member that is pivotably supported and rotatably holds the feed roller, the holding member pivotably between a first holding position that holds the feed roller in the contact position, a second holding position that holds the feed roller in the retracted position, and a third holding position between the first and second holding positions. A first restricting member is movable between a first restricting position that contacts the retaining member located at the second retaining position and restricts the retaining member from swinging from the second retaining position toward the third retaining position, and a first allowable position that allows the retaining member to swing from the second retaining position toward the third retaining position. A second restricting member is movable to a second restricting position that contacts the retaining member located at the third retaining position and restricts the retaining member from swinging from the third retaining position toward the first retaining position, and to a second allowable position that allows the retaining member to swing from the third retaining position toward the first retaining position. A feeding unit having, Equipped with, The first restricting member and the second restricting member are positioned in the first restricting position and the second restricting position, respectively, when the seat support portion is pulled out from the main body of the device. When the sheet support portion is mounted on the device body to which the feeding unit is attached, it abuts against the first restricting member located at the first restricting position at the first abutment position, and abuts against the second restricting member located at the second restricting position at the second abutment position downstream of the first abutment position in the mounting direction. When the feeding unit is mounted on the main body of the device and the sheet support is mounted on the main body of the device, the holding member swings from the second holding position to the third holding position as the first regulating member is pressed by the sheet support and moves from the first regulating position to the first allowable position, and the holding member swings from the third holding position to the first holding position as the second regulating member is pressed by the sheet support and moves from the second regulating position to the second allowable position. A sheet feeding device characterized by the following features.

16. A sheet feeding device according to any one of claims 1 to 15, The system includes an image forming unit that forms an image on a sheet fed from the aforementioned sheet feeding device. An image forming apparatus characterized by the following:

Images