Sheet feeding device and image forming apparatus

Abstract

The attachment / detachment unit is replaced while the separation surface remains attached to the sheet feeding device. [Solution] A sheet feeding device comprising: a loading section on which sheets are loaded; a feeding rotating body; a separation section having a separation surface; and a detachable unit detachably provided to the separation section, the detachable unit having a sheet separation section that separates the sheets one by one together with the separation surface by contacting the sheets fed by the feeding rotating body; wherein the direction toward the feeding rotating body from the separation surface among the directions perpendicular to the sheet feeding direction and the rotation axis direction of the feeding rotating body is defined as the projection direction, and when the detachable unit is attached to the separation section, the sheet separation section is located downstream of the separation surface in the projection direction, and when the detachable unit is attached to the separation section, the portion of the detachable unit other than the sheet separation section is located upstream of the separation surface in the projection direction.

Description

Technical Field

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

Background Art

[0002] Conventionally, a sheet feeding device has been proposed that includes an inclined member having an inclined surface and a separation piece unit detachably provided on the inclined member (see Patent Document 1). The separation piece unit has a plurality of separation pieces and a support portion that supports the plurality of separation pieces. The support portion is provided with an upper surface that is flush with the inclined surface in a state where the separation piece unit is attached to the inclined member. The sheet fed by the feeding roller is separated one by one by rubbing against the inclined surface of the inclined member, the upper surface of the support portion of the separation piece unit, and the plurality of separation pieces.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The plurality of separation pieces described in Patent Document 1 are provided so as to protrude more than the inclined surface of the inclined member and the upper surface of the support portion that supports the separation pieces. Therefore, the plurality of separation pieces may wear out earlier than the inclined surface of the inclined member, which is the separation surface, and the upper surface of the support portion. Since the separation piece unit is configured as an integral unit of the support portion and the plurality of separation pieces, when the separation piece unit is replaced, the upper surface of the support portion that has not yet worn out is also replaced together.

[0005] Therefore, an object of the present invention is to provide a sheet feeding device in which a detachable unit can be replaced while leaving the separation surface in the sheet feeding device, and an image forming apparatus including the same. [Means for solving the problem]

[0006] One aspect of the present invention is a sheet feeding device comprising: a loading section on which sheets are loaded; a feeding rotating body for feeding the sheets loaded in the loading section toward an image forming section in a sheet feeding direction; a separation section having a separation surface arranged to be in contact with the sheets fed by the feeding rotating body; and a detachable unit detachably provided to the separation section, the detachable unit having a sheet separation section that separates the sheets one by one together with the separation surface by contacting the sheets fed by the feeding rotating body, wherein the direction toward the feeding rotating body from the separation surface is defined as the projection direction, and when the detachable unit is attached to the separation section, the sheet separation section is located downstream of the separation surface in the projection direction, and when the detachable unit is attached to the separation section, the portion of the detachable unit other than the sheet separation section is located upstream of the separation surface in the projection direction.

[0007] Another aspect of the present invention is a sheet feeding device comprising: a loading section on which sheets are loaded; a feeding rotating body for feeding the sheets loaded in the loading section toward an image forming section in a sheet feeding direction; a separation section having a separation surface positioned to be in contact with the sheets fed by the feeding rotating body; and a detachable unit detachably provided to the separation section, the detachable unit having a sheet separation section that separates the sheets one by one together with the separation surface by contacting the sheets fed by the feeding rotating body, wherein the direction toward the feeding rotating body from the separation surface is defined as the protruding direction, the direction perpendicular to the sheet feeding direction and the rotation axis direction of the feeding rotating body, and when the detachable unit is attached to the separation section, the sheet separation section is located downstream of the separation surface in the protruding direction, and when the detachable unit is attached to the separation section, the portion of the detachable unit other than the sheet separation section does not come into contact with the sheets fed by the feeding rotating body. [Effects of the Invention]

[0008] According to the present invention, the attachment / detachment unit can be replaced while the separation surface remains attached to the sheet feeding device. [Brief explanation of the drawing]

[0009] [Figure 1] A schematic diagram showing an image forming apparatus according to the first embodiment. [Figure 2] (a) is a perspective view showing the sheet feeding device with the cassette attached to the main body of the device, and (b) is a perspective view showing the cassette removed from the main body of the device and its surrounding components. [Figure 3] (a) is a perspective view showing the sheet separation unit attached to the separation wall, (b) is a perspective view showing the sheet separation unit being removed from the separation wall, and (c) is a perspective view showing the sheet separation unit after it has been removed from the separation wall. [Figure 4] A perspective view showing a section of the sheet separation unit attached to the separation wall that has been cut away. [Figure 5] (a) is a perspective view showing a sheet separation unit according to the second embodiment, and (b) is a perspective view showing a sheet separation unit removed from the separation wall. [Figure 6] A perspective view showing a section of the sheet separation unit attached to the separation wall that has been cut away. [Figure 7] (a) is a perspective view showing the locking member and sheet separation unit according to the third embodiment assembled to the separation wall, and (b) is a perspective view showing the locking member and sheet separation unit removed from the separation wall. [Figure 8] (a) is a perspective view showing the cover according to the fourth embodiment in the closed position, (b) is a perspective view showing the cover in the open position, and (c) is a perspective view showing the sheet separation unit removed from the separation wall. [Figure 9] (a) is a perspective view showing the cover according to the fifth embodiment in the closed position, (b) is a perspective view showing the cover in the open position, and (c) is a perspective view showing the sheet separation unit removed from the separation wall. [Figure 10] A perspective view showing a sheet separation unit and a portion of its cover attached to the separation wall, with the latter partially cut away. [Figure 11] (a) is a perspective view showing a modified example of the fifth embodiment in which the separation wall and sheet separation unit are provided on the main body of the device, and (b) is a perspective view showing a modified example of the fifth embodiment in which the cassette is pulled out in the direction of arrow B. [Figure 12] (a) is a perspective view showing the cover according to the sixth embodiment in the closed position, (b) is a perspective view showing the cover in the open position, and (c) is a perspective view showing the sheet separation unit removed from the separation wall. [Figure 13] A diagram showing an example of an image forming apparatus having the configuration of the sixth embodiment. [Figure 14] (a) is a diagram showing the positional relationship between the sheet separation portion, the separation slope, and the slope according to the first embodiment, and (b) is a diagram showing how the sheets are separated one by one by the sheet separation portion and the separation slope. [Modes for carrying out the invention]

[0010] <First Embodiment> [Overall structure] First, a first embodiment of the present invention will be described. The image forming apparatus 1 is an electrophotographic laser beam printer and, as shown in Figure 1, has an image forming unit 80 that forms an image on a sheet S, a sheet feeding device 90, and a fixing device 31. Note that the term "image forming apparatus" includes printers, copiers, facsimile machines, and multifunction devices, and refers to a device 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 document. In addition to the main unit that has an image forming function, an image forming apparatus may have auxiliary equipment such as optional feeders, image reading devices, and sheet processing devices connected to it, and the entire system with such auxiliary equipment connected is also a type of image forming apparatus.

[0011] The image forming unit 80 includes four process cartridges PY, PM, PC, and PK that form toner images of four colors, namely yellow (Y), magenta (M), cyan (C), and black (K), and a scanner 21.

[0012] The four process cartridges PY, PM, PC, and PK have the same configuration except for the colors of the images they form. Therefore, only the configuration of the process cartridge PY and the image forming process will be described, and the descriptions of the process cartridges PM, PM, and PK will be omitted.

[0013] The process cartridge PY has a photosensitive drum 22, a charging roller (not shown), and a developing roller 23. The photosensitive drum 22 is formed by applying an organic photoconductive layer on the outer periphery of an aluminum cylinder and rotates by a drive motor (not shown). In addition, the image forming unit 80 is provided with an intermediate transfer belt 25 wound around a drive roller 25a and a tension roller 25b, and primary transfer rollers 24Y, 24M, 24C, and 24K are provided inside the intermediate transfer belt 25.

[0014] The fixing device 31 has a fixing roller 31a heated by a heater (not shown) and a pressure roller 31b that presses against the fixing roller 31a. The sheet feeding device 90 is provided at the lower part of the image forming apparatus 1 and includes a cassette 11 that supports the sheet S, a pickup roller 12 as a feeding rotating body that feeds the sheet S, and the like. The sheet S includes papers such as paper and envelopes, plastic films such as overhead projector sheets (OHP), cloth, and the like. Also, instead of the pickup roller 12, a feeding belt or the like that adsorbs and conveys the sheet by air may be applied.

[0015] Next, the image forming operation of the image forming apparatus 1 configured as described above will be described. When an image signal is input from a personal computer or the like (not shown) to the scanner 21, laser light corresponding to the image signal is irradiated onto the photosensitive drum 22 of the process cartridge PY from the scanner 21.

[0016] At this time, the surface of the photosensitive drum 22 is uniformly charged to a predetermined polarity and potential by the charging roller 7, and an electrostatic latent image is formed on the surface when laser light is shone from the scanner 21. The electrostatic latent image formed on the photosensitive drum 22 is developed by the developer unit 8, and a yellow (Y) toner image is formed on the photosensitive drum 22.

[0017] Similarly, laser light from the scanner 21 is shone onto each photosensitive drum of process cartridges PM, PC, and PK, forming magenta (M), cyan (C), and black (K) toner images on each drum. The toner images of each color formed on each drum are transferred to the intermediate transfer belt 25 by primary transfer rollers 24Y, 24M, 24C, and 24K, and then transported to the secondary transfer roller 26 by the intermediate transfer belt 25, which is rotated by the drive roller 25a. The image formation process for each color is performed at a timing that overlaps with the upstream toner image that has been primary transferred onto the intermediate transfer belt 25.

[0018] In parallel with this image formation process, the sheet S contained in the cassette 11 of the sheet feeding device 90 is fed out by the pickup roller 12 and then transported to the registration roller pair 15 via the transport guide 10 and the transport roller pair 14. The sheet S, whose skew has been corrected by the registration roller pair 15, is transported at a predetermined transport timing. Then, the full-color toner image on the intermediate transfer belt 25 is transferred to the sheet S by a secondary transfer bias applied to the secondary transfer roller 26.

[0019] The sheet S onto which the toner image has been transferred is subjected to predetermined heat and pressure by the fixing roller 31a and pressure roller 31b of the fixing device 31, causing the toner to melt and solidify (fix) to the sheet. The sheet S that has passed through the fixing device 31 is discharged into the discharge tray 34 by the discharge roller pair 32.

[0020] [Sheet feeding device] Next, the sheet feeding device 90 will be described using Figures 2(a) to 4. Figure 2(a) is a perspective view showing the sheet feeding device 90 with the cassette 11 attached to the device body 1A, and Figure 2(b) is a perspective view showing the cassette 11 and its surrounding components after being removed from the device body 1A. Figure 3(a) is a perspective view showing the sheet separation unit 62 attached to the separation wall 60, and Figure 3(b) is a perspective view showing the sheet separation unit 62 being removed from the separation wall 60. Figure 3(c) is a perspective view showing the sheet separation unit 62 after it has been removed from the separation wall 60. Figure 4 is a perspective view showing a part of the sheet separation unit 62 attached to the separation wall 60 cut off.

[0021] As shown in Figures 1 and 2(a), the cassette 11 of the sheet feeding device 90 is mounted on the main body 1A of the image forming apparatus 1 so as to be retractable. The cassette 11 in this embodiment is configured to be retractable in the direction towards the front of the page in Figure 1. The cassette 11 as a retractable unit includes a cassette frame 9, a tray 50 as a loading section on which sheets S are loaded, a separation wall 60, a sheet separation unit 62, and the like.

[0022] As shown in Figure 2(a), the main body of the device 1A has a rotatably supported roller rotation shaft 12s, and a pickup arm 12a is rotatably supported on the roller rotation shaft 12s. The pickup arm 12a rotatably supports the pickup roller 12. The main body of the device 1A also has a roller drive shaft 44 that is rotationally driven by a motor M1. A gear 45 is fixed to the roller drive shaft 44, and when the cassette 11 is mounted on the main body of the device 1A, the rotation of the gear 45 is transmitted to the pickup roller 12 via the idler gear train 43, the roller rotation shaft 12s, and the pickup gear train 42.

[0023] Furthermore, a lift input shaft 54 ​​is rotatably supported at one end of the cassette frame 9. This shaft is driven by a lift motor M2 located on the device body 1A, while the cassette 11 is mounted on the device body 1A. A lift input gear 53 is fixed to the lift input shaft 54 ​​and meshes with a fan-shaped lift gear 51. The lift gear 51 rotates integrally with a lift plate 51a located below the tray 50. The tray 50 is pressed upward by the lift plate 51a as the lift plate 51a rotates due to the drive of the lift motor M2, and rotates upward around the pivot axis 50a. As a result, the sheet S loaded on the tray 50 rises to a position where it can be fed by the pickup roller 12.

[0024] Next, the configuration of the sheet feeding device 90 near the separation wall 60 will be explained using Figures 2(b) to 4. Figure 4 is a perspective view taken from the opposite side of Figure 3(a), with a portion of the upper part of the separation wall 60 cut off, in order to explain the configuration around the separation wall 60.

[0025] As shown in Figures 2(b) and 3(a), the cassette frame 9 of the cassette 11 holds the separation wall 60. The separation wall 60, as a separation section, has a separation inclined surface 60a that is positioned to be in contact with the sheet S fed by the pickup roller 12. As shown in Figure 3(c), the separation inclined surface 60a has a first inclined surface 30L and a second inclined surface 30R that are arranged side by side in the width direction W, which will be described later. The separation wall 60 is provided with an opening 66 between the first inclined surface 30L and the second inclined surface 30R. The opening 66 opens in a direction perpendicular to the separation inclined surface 60a, that is, toward the downstream direction in the protrusion direction PD, which will be described later. A sheet separation unit 62, which will be described later, is inserted into the opening 66. Note that the separation wall 60 is not limited to a single member, but may be composed of a first member having the first inclined surface 30L and a second member having the second inclined surface 30R. It may also include other members besides the first and second members.

[0026] A pair of retaining members 65L and 65R are attached to the opening 66. In the following, as shown in Figures 2(a) and 2(b), the width direction of the sheet S that is perpendicular to the sheet feeding direction FD, which is the direction in which the pickup roller 12 feeds the sheet S, will be referred to as the width direction W. In other words, the width direction W intersects the sheet feeding direction FD. The width direction W is also parallel to the rotation axis of the pickup roller 12, i.e., the rotation axis direction. Of the pair of members provided side by side in the width direction W, the member on the left facing the separation slope 60a will be denoted with the letter "L", and the member on the right will be denoted with the letter "R". Since the pair of members provided in this way have similar configurations, only one will be described, and the description of the other will be omitted as appropriate.

[0027] Each of the holding members 65L and 65R has a sheet contact surface 65a. The sheet contact surface 65a is located upstream of the separation slope 60a in the protruding direction PD. The protruding direction PD is the direction from the separation slope 60a toward the pickup roller 12, which is perpendicular to the sheet feeding direction FD and the width direction W. In other words, the sheet contact surface 65a is located further away from the separation slope 60a in the protruding direction PD than the feeding path 17 (see Figure 1), which is the conveying path through which the sheet S fed by the pickup roller 12 passes. That is, the sheet contact surface 65a is located upstream of the separation slope 60a in the protruding direction PD. For this reason, the sheet contact surface 65a is less likely to prevent the sheet S from coming into contact with the separation slope 60a.

[0028] Furthermore, the retaining members 65L and 65R, which act as restricting members, are supported on the separation wall 60 so as to be movable in the width direction W, and are slidable between the retaining position shown in Figure 3(a) and the separated positions shown in Figures 3(b) and 3(c). In the retaining position, the retaining members 65L and 65R hold the sheet separation unit 62 so as to restrict the sheet separation unit 62 inserted into the opening 66 from being removed from the separation wall 60. Then, the retaining members 65L and 65R move to the separated positions shown in Figures 3(b) and 3(c) by sliding in the directions of arrows A1 and A2, respectively. The direction of arrow A1 is the direction away from the retaining member 65R, which is parallel to the width direction W. The direction of arrow A2 is the direction away from the retaining member 65L, which is parallel to the width direction W. The retaining position, as a restricting position, is a position close to the center of the separation wall 60 in the width direction W, and the separated positions, as an allowable position, are a position further from the center of the separation wall 60 in the width direction W than the retaining position. In other words, the holding members 65L and 65R move away from each other in the direction from the holding position to the separated position.

[0029] The retaining members 65L and 65R cover a portion of the opening 66 in the retaining position and widen the opening area of ​​the opening 66 by moving away from the retaining position. Therefore, in the separated position, the retaining members 65L and 65R release the hold on the sheet separation unit 62, allowing the sheet separation unit 62 to be removed from the separation wall 60.

[0030] The sheet separation unit 62 is detachably mounted to the separation wall 60 and has a pair of sheet separation sections 63L and 63R that, together with the separation slope 60a, separate the sheets one by one by contacting the sheets S fed by the pickup roller 12. The sheet separation sections 63L and 63R are located downstream of the separation slope 60a in the protruding direction PD. In other words, when the sheet separation unit 62 is mounted on the separation wall 60, the sheet separation sections 63L and 63R protrude further than the separation slope 60a toward the feeding path 17. Therefore, the sheet separation sections 63L and 63R are more likely to come into contact with the sheets S passing through the feeding path 17 than the separation slope 60a.

[0031] In this embodiment, the pair of sheet separation sections 63L and 63R constitute the sheet separation section 63. Furthermore, the sheet separation section 63 is not limited to a pair of sheet separation sections 63L and 63R; it may consist of only one sheet separation section, or three or more sheet separation sections. It is desirable that one or more sheet separation sections be provided symmetrically with respect to the center in the width direction W of the supply passage 17.

[0032] In this embodiment, the sheet separation unit 62, which serves as a detachable unit, has one end FE and the other end SE in the width direction W, as shown in Figure 3(c). The sheet separation portion 63L, which serves as the first sheet separation portion, is located closer to the one end FE than to the other end SE, and the sheet separation portion 63R, which serves as the second sheet separation portion, is located closer to the other end SE than to the one end FE. These sheet separation portions 63L and 63R are arranged symmetrically with respect to the center of the supply path 17 in the width direction W.

[0033] Furthermore, the sheet separation unit 62 has a slope 62e positioned between a pair of sheet separation sections 63L and 63R in the width direction W. The slope 62e is positioned upstream of the separation slope 60a in the protrusion direction PD. In other words, the amount of protrusion of the slope 62e toward the feed passage 17 is less than that of the separation slope 60a. For this reason, although the slope 62e faces the feed passage 17, it does not come into contact with the sheet S passing through the feed passage 17. Also, when the sheet separation unit 62 is mounted on the separation wall 60, the parts of the sheet separation unit 62 other than the sheet separation sections 63L and 63R are configured not to come into contact with the sheet S fed by the pickup roller 12, not limited to the slope 62e. This is because, when the sheet separation unit 62 is mounted on the separation wall 60, the parts of the sheet separation unit 62 other than the sheet separation sections 63L and 63R are located upstream of the separation slope 60a with respect to the protrusion direction PD.

[0034] Incidentally, in order to separate thin paper or other sheets with low rigidity (basis weight) into individual sheets, the separation slope 60a of the separation wall 60 alone may be insufficient. The sheet separation sections 63L and 63R have surfaces formed with irregularities or are made of materials with a higher coefficient of friction than the separation slope 60a and the sheet contact surface 65a in order to improve the sheet separation performance of the sheets S. As a result, thin paper or other sheets with low rigidity that are fed by the pickup roller 12 and transported along the feeding path 17 also come into contact with the sheet separation sections 63L and 63R together with the separation slope 60a, and are separated into individual sheets.

[0035] In this embodiment, the sheet separation portions 63L and 63R are defined as the parts of the sheet separation unit 62 that protrude beyond the separation slope 60a toward the supply path 17 in the protrusion direction PD when the sheet separation unit 62 is mounted on the separation wall 60. Preferably, at least a portion of the sheet separation portions 63L and 63R is configured to have a higher coefficient of friction than the separation slope 60a. For example, the separation slope 60a may be made of a resin material, and at least a portion of the sheet separation portions 63L and 63R may be made of a rubber material, for example, which has a higher coefficient of friction than the resin material. If only the portion made of such rubber material wears down, only that portion may be replaced.

[0036] Furthermore, in this embodiment, as shown in Figure 3(c), in the width direction W, the width D1 of the opening 66 is longer than the distance D2 between the sheet separation portion 63L as the first separation piece and the sheet separation portion 63R as the second separation piece. Because the opening 66 has a wide opening area in this way, the sheet separation unit 62 can be easily attached to the opening 66, improving the ease of replacing the sheet separation unit 62.

[0037] As shown in Figures 3(b) and 4, near the opening 66, on the back side of the separation slope 60a of the separation wall 60, there are contact portions 61L and 61R and a biasing member 64. The sheet separation unit 62 has a pair of unit contact surfaces 62aL and 62aR that are contacted parts that can come into contact with the contact portions 61L and 61R of the separation wall 60. The biasing member 64 includes, for example, a compression coil spring 64a supported by the separation wall 60 and a plate member 64b fixed to the compression coil spring 64a and capable of coming into contact with the sheet separation unit 62.

[0038] The unit contact surfaces 62aL and 62aR of the sheet separation unit 62 contact the contact portions 61L and 61R of the separation wall 60 when the sheet separation unit 62 is inserted into the opening 66 and biased by the biasing member 64. This positions the sheet separation unit 62 relative to the separation wall 60. In other words, the biasing member 64 biases the sheet separation unit 62 in the protruding direction PD toward the supply passage 17 when the sheet separation unit 62 is mounted on the separation wall 60. At this time, the unit contact surfaces 62aL and 62aR are located upstream of the contact portions 61L and 61R in the protruding direction PD.

[0039] The sheet separation sections 63L and 63R wear down due to friction with the sheet S. As wear progresses, the uneven surface of the sheet separation sections 63L and 63R becomes flatter, reducing the separation resistance, and the height of the sheet separation sections 63L and 63R decreases. This prevents the sheet separation sections 63L and 63R from protruding appropriately from the separation slope 60a, leading to a decrease in separation performance. Therefore, when the number of sheets S passed through increases and the separation performance deteriorates due to wear of the sheet separation sections 63L and 63R, it is necessary to replace the sheet separation unit 62, including the sheet separation sections 63L and 63R.

[0040] [Replacement of seat separation unit] Next, the method for replacing the sheet separation unit 62 will be explained using Figures 3(a) to 3(c). When removing the sheet separation unit 62 from the separation wall 60 of the cassette 11, as shown in Figure 3(a), the user accesses the sheet separation unit 62 from the side facing the separation slope 60a. When the sheet separation unit 62 is attached to the separation wall 60, its removal from the separation wall 60 is restricted by the retaining members 65L and 65R located in the holding position.

[0041] In the following, in the width direction W, the side closer to the center of the supply path 17 is considered the inside, and the side further from the center of the supply path 17 is considered the outside. As shown in Figure 4, when the sheet separation unit 62 is mounted on the separation wall 60, in the width direction W, the tip 621L of the unit contact surface 62aL is located outside the edge 611L of the contact portion 61L. Similarly, in the width direction W, the tip 621R of the unit contact surface 62aR is located outside the edge 611R of the contact portion 61R. That is, in the width direction W, the distance D5 between the tip 621L and the tip 621R is longer than the gap between the edge 611L and the edge 611R, i.e., the width D1 of the opening 66. Therefore, the sheet separation unit 62 is biased in the protruding direction PD by the biasing member 64, so that the unit contact surfaces 62aL and 62aR are pressed against the contact portions 61L and 61R, and the unit is held by the separation wall 60.

[0042] Furthermore, when the retaining members 65L and 65R are in the retaining position, the distance D6 between the retaining members 65L and 65R in the width direction W is shorter than the width D1 and the distance D5. At this time, the width of the opening 66 corresponds to the distance D6, not the width D1 mentioned above. When the retaining members 65L and 65R are in the retaining position and the width of the opening 66 is the distance D6, even if the posture of the sheet separation unit 62 is changed within the space SP in which the biasing member 64 is provided, the unit contact surfaces 62aL and 62aR will not pass through the opening 66. For this reason, the removal of the sheet separation unit 62 from the separation wall 60 is restricted. When the retaining members 65L and 65R are in the separated position and the width of the opening 66 is the width D1, the unit contact surfaces 62aL and 62aR can pass through the opening 66 by changing the posture of the sheet separation unit 62 within the space SP in which the biasing member 64 is provided.

[0043] First, the user moves the retaining members 65L and 65R, which are located in the holding position, in the directions of arrows A1 and A2, respectively, as shown in Figure 3(b), thereby moving the retaining members 65L and 65R to a separated position. This widens the opening area of ​​the opening 66. In other words, the width of the opening 66 in the width direction W increases from a distance D6 to a width D1. This releases the lock on the sheet separation unit 62 by the retaining members 65L and 65R.

[0044] Next, the user changes the orientation of the sheet separation unit 62 by pushing it into the space SP against the biasing force of the biasing member 64. Specifically, the user presses the sheet separation unit 62 so that the unit contact surfaces 62aL and 62aR are separated from the contact portions 61L and 61R of the separation wall 60. Furthermore, the user tilts the sheet separation unit 62 diagonally with respect to the protruding direction PD and the width direction W, and pulls one of the unit contact surfaces 62aL and 62aR out of the opening 66. Then, by pulling out the other unit contact surface 62aL and 62aR out of the opening 66, the entire sheet separation unit 62 is pulled out of the opening 66, and the sheet separation unit 62 can be removed from the separation wall 60 as shown in Figure 3(c).

[0045] When assembling the sheet separation unit 62 to the separation wall 60, the reverse procedure is followed when removing the sheet separation unit 62 from the separation wall 60. First, the user inserts the sheet separation unit 62 into the opening 66 with the holding members 65L and 65R positioned apart. At this time, the user tilts the sheet separation unit 62 diagonally with respect to the protruding direction PD and the width direction W, and first inserts one of the unit contact surfaces 62aL and 62aR into the opening 66. Then, while returning the position of the sheet separation unit 62 to a position parallel to the width direction W, the other unit contact surface 62aL and 62aR is also inserted into the opening 66. As a result, the sheet separation unit 62 is inserted into the opening 66 until the unit contact surfaces 62aL and 62aR face the contact portions 61L and 61R of the separation wall 60.

[0046] Then, when the user moves the holding members 65L and 65R to the holding position, the sheet separation unit 62 is prevented from falling off the separation wall 60. At this time, when the user releases their hand from the sheet separation unit 62, the sheet separation unit 62 is biased by the biasing member 64 so that the unit contact surfaces 62aL and 62aR come into contact with the contact portions 61L and 61R. As a result, the sheet separation portions 63L and 63R of the sheet separation unit 62 are precisely positioned relative to the separation wall 60.

[0047] As described above, in this embodiment, when the sheet separation unit 62 is mounted on the separation wall 60, the parts other than the sheet separation portions 63L and 63R are configured so that they do not come into contact with the sheet S fed by the pickup roller 12.

[0048] Here, using Figures 14(a) and 14(b), the positional relationship between the sheet separation portions 63L, 63R, the separation slope 60a, and the slope 62e when the sheet separation unit 62 is mounted on the separation wall 60 will be explained. Figure 14(a) is a diagram showing the positional relationship between the sheet separation portions 63L, 63R, the separation slope 60a, and the slope 62e according to the first embodiment. Figure 14(b) is a diagram showing how the sheets are separated one by one by the sheet separation portions 63L, 63R, and the separation slope 60a. Figures 14(a) and 14(b) are views in the width direction W.

[0049] As shown in Figure 14(a), the sheet separation portions 63L and 63R of the sheet separation unit 62 protrude in the protruding direction PD from the separation slope 60a. The slope 62e of the sheet separation unit 62 is positioned upstream of the separation slope 60a in the protruding direction PD. Furthermore, as shown in Figure 3(a), the slope 62e of the sheet separation unit 62 is positioned between the sheet separation portions 63L and 63R in the width direction W. The first slope 30L and the second slope 30R of the separation slope 60a are positioned outside the sheet separation portions 63L and 63R, respectively.

[0050] Therefore, as shown in Figure 14(a), when a sheet S1, such as thin paper or plain paper, is fed by the pickup roller 12, it comes into contact with the sheet separation sections 63L and 63R and is transported in the sheet feeding direction FD. At this time, a sheet S2 below the uppermost sheet S1 may be fed along with the uppermost sheet S1. The fed sheet S2 comes into contact with the sheet separation sections 63L and 63R. Since the frictional force between the sheet separation sections 63L and 63R and the sheet S2 is greater than the frictional force between the sheet S1 and the sheet S2, the sheet S2 is stopped by the sheet separation sections 63L and 63R, and only the sheet S1 is fed by the pickup roller 12. As a result, only the sheet S1 is separated from the sheet S2.

[0051] Furthermore, if a highly rigid sheet, such as cardboard, is transported, the sheet separation portions 63L and 63R are pressed against the transported sheet. This can cause the sheet separation unit 62 to move upstream in the protruding direction PD against the biasing force of the biasing member 64. Even in this case, the sheet separation portion 63L and 63R do not move upstream in the protruding direction PD beyond the separation slope 60a because the separation slope 60a receives the load of the sheet. In other words, the sheet can be separated one sheet at a time by the flush sheet separation portions 63L and 63R and the separation slope 60a.

[0052] Therefore, the sheet separation unit 62 only has sheet separation portions 63L and 63R that wear down due to friction with the sheet S, and the sheet separation unit 62 only needs to be replaced at the same time as the sheet separation portions 63L and 63R need to be replaced. This allows the sheet separation unit 62 to be replaced while the separation wall 60 with the separation slope 60a remains in the sheet feeding device 90 (device body 1A), and the sheet separation unit 62 can be replaced at the appropriate time. In other words, the replacement timing of the sheet separation unit 62 is not affected by parts other than the sheet separation portions 63L and 63R, and replacing the sheet separation unit 62 prevents the replacement of parts other than the sheet separation portions 63L and 63R that do not need to be replaced. Furthermore, the sheet separation unit 62 does not have a slope that is flush with the separation slope 60a, which allows the sheet separation unit 62 to be made smaller and less expensive.

[0053] Furthermore, in this embodiment, the sheet separation unit 62 can be easily attached to and detached from the separation wall 60 simply by sliding the holding members 65L and 65R in the width direction W. Also, when the sheet separation unit 62 is mounted on the separation wall 60, it is biased by the biasing member 64, and the unit contact surfaces 62aL and 62aR contact the contact parts 61L and 61R, thereby positioning it accurately with respect to the separation wall 60. This improves the relative positional accuracy between the sheet separation portions 63L and 63R and the separation slope 60a, and the sheet separation portions 63L and 63R are positioned to protrude further than the separation slope 60a in the protruding direction PD toward the supply path 17. As a result, the sheets S can be reliably separated one by one by the sheet separation portions 63L and 63R and the separation slope 60a, and transport defects such as double feeding can be suppressed.

[0054] Furthermore, the biasing force of the biasing member 64 is set to be greater than the contact pressure when a low-rigidity sheet S, such as thin paper, contacts the sheet separation unit 62, and less than the contact pressure when a high-rigidity sheet S, such as cardboard, contacts the sheet separation unit 62. Therefore, when the sheet separation unit 62 is pressed by a high-rigidity (basis weight) sheet S, such as cardboard, the unit contact surfaces 62aL and 62aR can move against the biasing force of the biasing member 64 in the direction that separates the contact portions 61L and 61R. At this time, even if a high-rigidity sheet S is fed, the separation slope 60a receives the load of the sheet S, which prevents the sheet separation portions 63L and 63R from moving upstream in the protruding direction PD relative to the separation slope 60a. As a result, the surfaces of the sheet separation portions 63L and 63R of the sheet separation unit 62 and the separation slope 60a become substantially flush, allowing the sheet S to be separated into individual sheets by the sheet separation portions 63L and 63R and the separation slope 60a.

[0055] In this embodiment, the separation slope 60a and the sheet contact surface 65a are formed in a planar shape, but the embodiment is not limited to this. The separation slope 60a and the sheet contact surface 65a may have, for example, a plurality of ribs extending along the conveying direction of the sheet S.

[0056] <Second Embodiment> Next, a second embodiment of the present invention will be described. The second embodiment omits the holding members 65L and 65R of the first embodiment and is configured with locking claws 162aL and 162aR on the sheet separation unit 62. For this reason, the same configuration as in the first embodiment will be omitted from the illustration or will be described using the same reference numerals in the illustration.

[0057] Figure 5(a) is a perspective view showing the sheet separation unit 162 according to the second embodiment, and Figure 5(b) is a perspective view showing the sheet separation unit 162 removed from the separation wall 60. Figure 6 is a perspective view showing a part of the sheet separation unit 162 attached to the separation wall 60 cut off.

[0058] As shown in Figures 5(a) to 6, the seat separation unit 162, which serves as a detachable unit, has a pair of seat separation portions 63L, 63R, a pair of arm portions 62bL, 62bR, and a pair of locking claws 162aL, 162aR. The locking claws 162aL, 162aR, which serve as contact portions, are provided at the tips of the pair of arm portions 62bL, 62bR.

[0059] When the sheet separation unit 162 is inserted into the opening 66 of the separation wall 60, the locking claws 162aL and 162aR are pressed against the edge of the opening 66, and the arm portions 62bL and 62bR undergo elastic deformation. When the sheet separation unit 162 is inserted into the opening 66 to its mounting position, the contact between the locking claws 162aL and 162aR and the edge of the opening 66 is released, and the arm portions 62bL and 62bR elastically return to their original position. As a result, the sheet separation unit 162, while mounted on the separation wall 60, is biased by the biasing member 64, and the locking claws 162aL and 162aR contact and engage with the contact portions 61L and 61R, thereby positioning it accurately relative to the separation wall 60. Furthermore, the locking claws 162aL and 162aR engage with the contact portions 61L and 61R, thereby preventing the sheet separation unit 162 from being removed from the separation wall 60.

[0060] In this embodiment as well, when the sheet separation unit 162 is mounted on the separation wall 60, the parts other than the sheet separation portions 63L and 63R are configured so that they do not come into contact with the sheet S fed by the pickup roller 12.

[0061] Therefore, the same effects as the first embodiment can be achieved with a simple configuration. Furthermore, when removing the sheet separation unit 162 from the separation wall 60, the user can elastically deform the arm portions 62bL and 62bR to bring them closer together and pull out the sheet separation unit 162 from the opening 66.

[0062] <Third Embodiment> Next, a third embodiment of the present invention will be described. In the third embodiment, locking members 70L and 70R are provided instead of the holding members 65L and 65R of the first embodiment. For this reason, the same configuration as in the first embodiment will be omitted from the illustration or will be described using the same reference numerals in the illustration.

[0063] Figure 7(a) is a perspective view showing the locking members 70L, 70R and the sheet separation unit 62 according to the third embodiment assembled to the separation wall 60. Figure 7(b) is a perspective view showing the locking members 70L, 70R and the sheet separation unit 62 removed from the separation wall 60.

[0064] As shown in Figures 7(a) and 7(b), locking members 70L and 70R, which act as restricting members, are detachably fixed to the separation wall 60 by screws 71L and 71R. When assembling the sheet separation unit 62 to the separation wall 60, the user removes the locking members 70L and 70R from the separation wall 60 and inserts the sheet separation unit 62 into the opening 66. At this time, the user inserts the sheet separation unit 62 into the opening 66 until the unit contact surfaces 62aL and 62aR of the sheet separation unit 62 face the contact portions 61L and 61R of the separation wall 60.

[0065] Then, when the user fixes the locking members 70L and 70R to the separation wall 60, the sheet separation unit 62 is prevented from falling off the separation wall 60. At this time, when the user releases their hand from the sheet separation unit 62, the sheet separation unit 62 is biased by the biasing member 64 so that the unit contact surfaces 62aL and 62aR contact the contact parts 61L and 61R. As a result, the sheet separation portions 63L and 63R of the sheet separation unit 62 are accurately positioned relative to the separation wall 60. This improves the relative positional accuracy between the sheet separation portions 63L and 63R and the separation slope 60a, and positions the sheet separation portions 63L and 63R to protrude further than the separation slope 60a in the protruding direction PD toward the feed path 17. Therefore, the sheets S can be reliably separated one by one by the sheet separation portions 63L and 63R and the separation slope 60a, and transport defects such as double feeding can be suppressed.

[0066] Furthermore, since the locking members 70L and 70R are firmly fixed to the separation wall 60 by screws 71L and 71R, the sheet separation unit 62 will not easily detach from the separation wall 60 at any time other than when replacing the sheet separation unit 62.

[0067] <Fourth Embodiment> Next, a fourth embodiment of the present invention will be described. The fourth embodiment is configured by providing a cover 67 instead of the retaining members 65L and 65R of the first embodiment. For this reason, the same configuration as in the first embodiment will be omitted from the illustration or will be described using the same reference numerals in the illustration.

[0068] Figure 8(a) is a perspective view showing the cover 67 in the closed position according to the fourth embodiment, and Figure 8(b) is a perspective view showing the cover 67 in the open position. Figure 8(c) is a perspective view showing the sheet separation unit 62 removed from the separation wall 60.

[0069] As shown in Figures 8(a) to 8(c), the cover 67 is supported by the separation wall 60 so as to be rotatable and openable around a rotation axis 67a. The cover 67 also has a sheet contact surface 67b that can contact the sheet S fed by the pickup roller 12, and openings 67cL and 67cR that are formed in the sheet contact surface 67b as second openings. As shown in Figure 8(a), when the cover 67 is in the closed position, the sheet contact surface 67b is positioned alongside the separation slope 60a in the width direction W. At this time, the sheet contact surface 67b is located upstream of the separation slope 60a in the protrusion direction PD. In other words, the amount of protrusion of the sheet contact surface 67b in the protrusion direction PD toward the feeding path 17 is less than that of the separation slope 60a. Therefore, the sheet contact surface 67b does not obstruct the sheet S from contacting the separation slope 60a.

[0070] The openings 67cL and 67cR are provided at positions corresponding to the sheet separation portions 63L and 63R of the sheet separation unit 62, which is mounted on the separation wall 60. Furthermore, the openings 67cL and 67cR are formed so that the sheet separation portions 63L and 63R protrude when the sheet separation unit 62 is mounted on the separation wall 60.

[0071] Furthermore, the cover 67 is configured to open and close the opening 66, which serves as the first opening. As shown in Figure 8(b), the opening 66 is opened by rotating the cover 67 from the closed position to the open position. In this state, the sheet separation unit 62 can be inserted into the opening 66 or removed from the separation wall 60, as described in the first embodiment.

[0072] In this embodiment as well, the unit contact surfaces 62aL and 62aR of the sheet separation unit 62 contact the contact portions 61L and 61R of the separation wall 60 when the sheet separation unit 62 is inserted into the opening 66 and biased by the biasing member 64. Then, by positioning the cover 67 in the closed position, the sheet separation portions 63L and 63R of the sheet separation unit 62 protrude from the openings 67cL and 67cR of the cover 67 into the supply path 17, respectively. This improves the relative positional accuracy between the sheet separation portions 63L and 63R and the separation slope 60a, and positions the sheet separation portions 63L and 63R in a position that protrudes downstream of the separation slope 60a in the protrusion direction PD. Therefore, the sheets S can be reliably separated one by one by the sheet separation portions 63L and 63R and the separation slope 60a, and transport defects such as double feeding can be suppressed.

[0073] As described above, this embodiment can achieve the same effects as the first embodiment. Furthermore, in this embodiment, by opening the cover 67 from the closed position to the open position, an opening 66 with a wide opening area can be opened, and the sheet separation unit 62 can be replaced through this opening 66. Therefore, the sheet separation unit 62 can be easily replaced, improving the workability of replacement. In addition, the cover 67 is provided with sheet contact surfaces 67b arranged in the width direction W on the sheet separation portions 63L, 63R and the separation slope 60a when the cover 67 is in the closed position. Therefore, even if the opening 66 is wide, the sheet separation performance is not affected, and the sheets S can be properly separated one by one.

[0074] In this embodiment, the separation slope 60a and the sheet contact surface 67b are formed in a planar shape, but the embodiment is not limited to this. The separation slope 60a and the sheet contact surface 67b may have, for example, a plurality of ribs extending along the conveying direction of the sheet S.

[0075] <Fifth Embodiment> Next, a fifth embodiment of the present invention will be described. The fifth embodiment is configured by changing the arrangement of the cover 67 in the fourth embodiment. For this reason, the same configuration as in the fourth embodiment will be omitted from the illustration or will be described using the same reference numerals in the illustration.

[0076] Figure 9(a) is a perspective view showing the cover 167 in the closed position according to the fifth embodiment, and Figure 9(b) is a perspective view showing the cover 167 in the open position. Figure 9(c) is a perspective view showing the sheet separation unit 62 removed from the separation wall 60. Figure 10 is a perspective view showing a portion of the sheet separation unit 62 and cover 167 attached to the separation wall 60 cut off.

[0077] As shown in Figures 9(a) and 9(b), the separation slope 60a of the separation wall 60 is provided with openings 60bL and 60bR, which serve as third openings from which the sheet separation portions 63L and 63R can protrude. As shown in Figures 9(a) to 9(c), the cover 167 is supported on the separation wall 60 so as to be rotatable and openable around a pivot axis 167a. The cover 167 is provided on the back side of the separation slope 60a and is configured to open and close an opening 166 provided on the back side of the separation slope 60a. That is, the opening 166 opens on the side of the separation slope 60a opposite to the supply passage 17. In other words, the opening 166 opens upstream in the protrusion direction PD. As shown in Figures 9(b) and 9(c), the cover 167 opens the opening 166 by rotating from the closed position to the open position. In this state, as described in the first embodiment, the sheet separation unit 62 can be inserted into the opening 166 or removed from the separation wall 60. In other words, in this embodiment, although the sheet separation unit 62 is attached to and detached from the separation wall 60 from the back side (opposite side) of the separation slope 60a, the configuration for positioning the sheet separation unit 62 on the separation wall 60 is the same as in the first embodiment.

[0078] Furthermore, in this embodiment, as shown in Figure 9(c), in the width direction W, the width D3 of the opening 166 is longer than the distance D2 between the sheet separation portion 63L and the sheet separation portion 63R (see Figure 9(a)). Because the opening 166 has a wide opening area, the sheet separation unit 62 can be easily attached to the opening 166, improving the ease of replacing the sheet separation unit 62.

[0079] When removing the sheet separation unit 62 from the separation wall 60 of the cassette 11, as shown in Figures 9(b) and 9(c), the user opens the cover 167 to the open position and accesses the sheet separation unit 62 from the back side of the separation slope 60a. Opening the cover 167 opens an opening 166 with a large opening area, and the sheet separation unit 62 can be replaced through this opening 166.

[0080] Next, the user pulls the sheet separation unit 62 forward, separating the unit contact surfaces 62aL and 62aR from the contact portions 61L and 61R of the separation wall 60, as shown in Figures 9(c) and 10. This allows the sheet separation unit 62 to be removed from the separation wall 60, as shown in Figure 9(c).

[0081] When assembling the sheet separation unit 62 to the separation wall 60, the procedure is the reverse of the procedure used when removing the sheet separation unit 62 from the separation wall 60. First, with the cover 167 in the open position, the user inserts the sheet separation unit 62 into the opening 166. At this time, the user inserts the sheet separation unit 62 into the opening 66 until the unit contact surfaces 62aL, 62aR of the sheet separation unit 62 face the contact portions 61L, 61R of the separation wall 60.

[0082] As shown in Figure 9(a), the user moves the cover 167 to the closed position, which prevents the sheet separation unit 62 from falling off the separation wall 60. The biasing member 64 is also supported by the cover 167. When the cover 167 is moved from the open position to the closed position, the sheet separation unit 62 is biased by the biasing member 64 so that the unit contact surfaces 62aL, 62aR come into contact with the contact portions 61L, 61R.

[0083] At this time, the sheet separation portions 63L and 63R of the sheet separation unit 62 protrude from the openings 60bL and 60bR of the separation slope 60a, respectively. In other words, after the sheet separation unit 62 is inserted into the opening 166 and the cover 167 is closed, the sheet separation portions 63L and 63R protrude from the openings 60bL and 60bR toward the feeding path 17. This improves the relative positional accuracy between the sheet separation portions 63L and 63R and the separation slope 60a, and positions the sheet separation portions 63L and 63R in a position that protrudes downstream of the separation slope 60a in the protrusion direction PD. Therefore, the sheets S can be reliably separated one by one by the sheet separation portions 63L and 63R and the separation slope 60a, and transport defects such as double feeding can be suppressed.

[0084] In this embodiment, by opening the cover 167 from the closed position to the open position, the opening 166 on the back side of the separation slope 60a, which has a wide opening area, can be opened, and the sheet separation unit 62 can be replaced from the opening 166. Therefore, even if an opening cannot be provided on the separation slope 60a side, or if replacement work cannot be performed from the separation slope 60a side, the sheet separation unit 62 can be easily replaced, improving the workability of replacement. Furthermore, since the opening 166 and the cover 167 are provided on the back side of the separation slope 60a, even if the opening 166 is wide, it does not affect the sheet separation performance of the sheet S, and the sheet S can be properly separated one by one.

[0085] Figure 11(a) is a perspective view showing a modified example of the fifth embodiment in which the separation wall 60 and the sheet separation unit 62 are provided on the main body 1A of the device. Figure 11(b) is a perspective view showing a modified example of the fifth embodiment in which the cassette 11 is pulled out in the direction of arrow B. As shown in Figures 11(a) and (b), when the separation wall 60 and the sheet separation unit 62 are provided on the main body 1A of the device, it can be difficult to access the separation slope 60a side due to the configuration and space constraints, and it may be difficult to replace the sheet separation unit 62 from the separation slope 60a side. Even in such a configuration, by arranging the opening 166 and the cover 167 on the back side of the separation slope 60a, the replacement of the sheet separation unit 62 can be easily performed, improving the ease of replacement.

[0086] In this embodiment, the separation slope 60a is formed in a planar shape, but it is not limited to this. The separation slope 60a may have, for example, a plurality of ribs extending along the conveying direction of the sheet S.

[0087] <Sixth Embodiment> Next, a sixth embodiment of the present invention will be described. The sixth embodiment is constructed by changing the arrangement of the cover 167 and the opening 166 of the fifth embodiment. For this reason, the same configuration as in the fifth embodiment will be omitted from the illustration or will be described using the same reference numerals in the illustration.

[0088] Figure 12(a) is a perspective view showing the cover 267 in the closed position according to the sixth embodiment, and Figure 12(b) is a perspective view showing the cover 267 in the open position. Figure 12(c) is a perspective view showing the sheet separation unit 62 removed from the separation wall 60.

[0089] As shown in Figures 12(a) and (b), the separation slope 60a of the separation wall 60 is provided with openings 60bL and 60bR from which the sheet separation portions 63L and 63R can protrude. As shown in Figures 12(a) to (c), the cover 267 is supported on the separation wall 60 so as to be rotatable and openable around a pivot axis 267a. The cover 267 is provided on the top surface 60c of the separation wall 60 and is configured to open and close an opening 266 provided on the top surface 60c. That is, the opening 266 opens vertically. As shown in Figures 12(b) and (c), the cover 267 opens the opening 266 by rotating from the closed position to the open position. In this state, as described in the first embodiment, the sheet separation unit 62 can be inserted into the opening 266 or removed from the separation wall 60. In other words, in this embodiment, although the sheet separation unit 62 is attached to and detached from the top surface 60c of the separation wall 60, the configuration for positioning the sheet separation unit 62 on the separation wall 60 is the same as in the first embodiment.

[0090] Furthermore, in this embodiment, as shown in Figure 12(b), in the width direction W, the width D4 of the opening 266 is longer than the distance D2 between the sheet separation portion 63L and the sheet separation portion 63R. Because the opening 266 has a wide opening area in this way, the sheet separation unit 62 can be easily attached to the opening 266, improving the ease of replacing the sheet separation unit 62.

[0091] When removing the sheet separation unit 62 from the separation wall 60 of the cassette 11, as shown in Figures 12(b) and 12(c), the user opens the cover 267 to the open position and accesses the sheet separation unit 62 from the top surface 60c side of the separation wall 60. Opening the cover 267 opens an opening 266 with a large opening area, and the sheet separation unit 62 can be replaced through this opening 266.

[0092] Next, the user pulls the sheet separation unit 62 upward, separating the unit contact surfaces 62aL and 62aR from the contact portions 61L and 61R of the separation wall 60, as shown in Figure 12(c). This allows the sheet separation unit 62 to be removed from the separation wall 60.

[0093] When assembling the sheet separation unit 62 to the separation wall 60, the procedure is the reverse of the procedure used when removing the sheet separation unit 62 from the separation wall 60. First, with the cover 267 in the open position, the user inserts the sheet separation unit 62 into the opening 266. At this time, the user inserts the sheet separation unit 62 into the opening 66 until the unit contact surfaces 62aL, 62aR of the sheet separation unit 62 face the contact portions 61L, 61R of the separation wall 60.

[0094] Then, as shown in Figure 12(a), when the user moves the cover 267 to the closed position, the sheet separation unit 62 is prevented from falling off the separation wall 60. Also, when the user releases their hand from the sheet separation unit 62, the sheet separation unit 62 is biased by the biasing member 64 so that the unit contact surfaces 62aL, 62aR contact the contact portions 61L, 61R. The biasing member 64 is supported by the separation wall 60. At this time, the sheet separation portions 63L, 63R of the sheet separation unit 62 protrude from the openings 60bL, 60bR of the separation slope 60a, respectively. This improves the relative positional accuracy between the sheet separation portions 63L, 63R and the separation slope 60a, and positions the sheet separation portions 63L, 63R in a position that protrudes downstream of the separation slope 60a in the protrusion direction PD. Therefore, the sheet S can be reliably separated into individual sheets by the sheet separation sections 63L, 63R and the separation slope 60a, thereby suppressing transport defects such as double feeding.

[0095] As described above, this embodiment can achieve the same effects as the first embodiment. Furthermore, in this embodiment, by opening the cover 267 from the closed position to the open position, the opening 266 provided on the top surface 60c of the separation wall 60, which has a wide opening area, can be opened, and the sheet separation unit 62 can be replaced from the opening 266. For this reason, even if an opening cannot be provided on the separation slope 60a side or the back side of the separation slope 60a, the sheet separation unit 62 can be easily replaced, improving the workability of replacement. In addition, since the opening 266 and the cover 267 are provided on the top surface 60c of the separation wall 60, even if the opening 266 is made wide, the sheet separation performance of the sheet S is not affected, and the sheet S can be properly separated one by one.

[0096] Figure 13 shows an example of an image forming apparatus 1B having the configuration of the sixth embodiment. As shown in Figure 13, the image forming apparatus 1B has a sheet feeding device 190 having the same configuration as the sheet feeding device 90 connected below the sheet feeding device 90. In this case, the sheets S fed from the lower sheet feeding device 190 are transported upward through a vertical transport path 18 provided in the upper sheet feeding device 90.

[0097] In this configuration, the vertical transport path 18 is located behind the separation slope 60a of the separation wall 60 of the sheet feeding device 90, making it difficult to provide an opening behind the separation slope 60a and perform the sheet separation unit 62 replacement work from that opening. Furthermore, the exterior surface of the image forming apparatus may be provided behind the separation slope 60a of the separation wall 60, and even in such a case, it is difficult to provide a wide opening behind the separation slope 60a for the replacement work of the sheet separation unit 62.

[0098] However, as in this embodiment, by providing an opening 266 and a cover 267 on the top surface 60c of the separation wall 60, the sheet separation unit 62 can be easily replaced, thereby improving the ease of replacement.

[0099] In this embodiment, the separation slope 60a is formed in a planar shape, but it is not limited to this. The separation slope 60a may have, for example, a plurality of ribs extending along the conveying direction of the sheet S.

[0100] <Other Embodiments> In all of the embodiments described above, the biasing member 64 biased the sheet separation unit to position it relative to the separation wall 60, but the configuration of the biasing member 64 is not limited. As mentioned above, the biasing member 64 may be composed of, for example, a compression coil spring 64a supported by the separation wall 60 and a plate member 64b fixed to the compression coil spring 64a and capable of contacting the sheet separation unit 62. Alternatively, the biasing member 64 may be composed solely of an elastic material such as a spring, rubber, or sponge.

[0101] Furthermore, in any of the above-described configurations, the separation wall 60 may be provided on the cassette 11 as described in Figures 2(a) and 2(b), or on the main body 1A of the device as described in Figures 11(a) and 11(b).

[0102] Furthermore, although the invention has been described using an electrophotographic image forming apparatus 1 in all of the above-described embodiments, the present invention is not limited thereto. For example, the present invention can also be applied to an inkjet image forming apparatus that forms an image on a sheet by ejecting ink liquid from a nozzle.

[0103] Summary of this disclosure This disclosure includes at least the following: (Composition 1) The loading section where the sheets are loaded, A feeding rotating body that feeds the sheets loaded in the loading section toward the image forming section in the sheet feeding direction, A separation section having a separation surface arranged to be in contact with the sheet fed by the aforementioned feeding rotating body, A detachable attachment unit is provided detachably with respect to the separation unit, and the attachment unit has a sheet separation section that separates the sheets one by one together with the separation surface by contacting the sheets fed by the feeding rotating body, The direction perpendicular to the sheet feeding direction and the rotation axis direction of the feeding rotating body, the direction from the separation surface toward the feeding rotating body, is defined as the protruding direction. When the attachment / detachment unit is mounted on the separation portion, the seat separation portion is located downstream of the separation surface in the protruding direction. When the attachment / detachment unit is attached to the separation portion, the portion of the attachment / detachment unit other than the seat separation portion is located upstream of the separation surface in the protruding direction. A sheet feeding device characterized by the following features. (Configuration 2) The separation portion has an opening into which the attachment / detachment unit, which is mounted to the separation portion, is inserted. A sheet feeding device according to configuration 1, characterized by the above. (Composition 3) The opening is open toward the downstream direction in the protruding direction. The sheet feeding device according to configuration 2, characterized in that (Composition 4) The opening is open toward the upstream direction in the protruding direction. The sheet feeding device according to configuration 2, characterized in that (Composition 5) The aforementioned opening is open in the vertical direction. The sheet feeding device according to configuration 2, characterized in that (Composition 6) The detachable unit has one end and the other end in the direction of the rotation axis, The sheet separation portion includes a first sheet separation portion provided in the direction of the rotation axis at a position closer to one end than the other end, and a second sheet separation portion provided in the direction of the rotation axis at a position closer to the other end than the one end, In the direction of the rotation axis, the width of the opening is longer than the distance between the first sheet separation portion and the second sheet separation portion. A sheet feeding device according to any one of configurations 2 to 5, characterized by the above. (Composition 7) The system further includes a restricting member that prevents the detachable unit inserted into the opening from being removed from the separation portion. A sheet feeding device according to any one of configurations 2 to 6, characterized by the above. (Composition 8) The restricting member is movable between a restricting position that restricts the removal of the detachable unit from the separation portion and a position that allows the removal of the detachable unit from the separation portion. The sheet feeding device according to configuration 7, characterized by the features described above. (Composition 9) The restricting member covers a portion of the opening at the restricting position and expands the opening area of ​​the opening by moving from the restricting position to the allowable position. A sheet feeding device according to configuration 8, characterized by the above. (Composition 10) The restricting member is removably fixed to the separation portion. The sheet feeding device according to configuration 7, characterized by the features described above. (Composition 11) The separation portion has a contact portion, The detachable unit has a contact portion that can contact the contact portion, The system further includes a biasing member that positions the detachable unit relative to the separation portion by biasing the detachable unit so that the contact portion contacts the contact portion while the detachable unit is mounted on the separation portion. A sheet feeding device according to any one of configurations 2 to 10, characterized by the above. (Composition 12) The biasing member biases the detachable unit in the protruding direction when the detachable unit is attached to the separation portion. The contact portion is located upstream of the contact portion in the protruding direction when the detachable unit is attached to the separation portion. A sheet feeding device according to configuration 11, characterized by the features described above. (Composition 13) The attachment / detachment unit is movable upstream in the protruding direction against the biasing force of the biasing member when the sheet separation portion is pressed by the sheet fed by the feeding rotating body. A sheet feeding device according to configuration 11 or 12, characterized by the above. (Composition 14) The contact portion is locked to the contact portion when the detachable unit is inserted into the opening, thereby restricting the detachable unit from being removed from the separation portion. A sheet feeding device according to any one of the configurations 11 to 13, characterized by the above. (Composition 15) The aforementioned opening is further provided with a cover that can be opened and closed. A sheet feeding device according to any one of configurations 2 to 14, characterized by the above. (Composition 16) The aforementioned opening is a first opening, The cover has a second opening, The seat separation portion protrudes from the second opening in the protruding direction after the cover is closed following the insertion of the attachment / detachment unit into the first opening. A sheet feeding device according to configuration 15, characterized by the features described above. (Composition 17) The aforementioned opening is a first opening, The separation surface of the separation portion has a third opening, The seat separation portion protrudes from the third opening in the protruding direction after the cover is closed following the insertion of the attachment / detachment unit into the first opening. A sheet feeding device according to configuration 15, characterized by the features described above. (Composition 18) The cover is supported in the separation section so as to be openable and closable. A sheet feeding device according to any one of configurations 15 to 17, characterized by the above. (Composition 19) At least a portion of the sheet separation section has a higher coefficient of friction than the separation surface. A sheet feeding device according to any one of configurations 1 to 18. (Composition 20) The main body of the device, The device further comprises a drawer unit that supports the loading section, the feeding and rotating body, the separation section, and the detachable unit, and is retractably mounted on the main body of the device. A sheet feeding device according to any one of configurations 1 to 19, characterized by the above. (Composition 21) The loading section where the sheets are loaded, A feeding rotating body that feeds the sheets loaded in the loading section toward the image forming section in the sheet feeding direction, A separation section having a separation surface arranged to be in contact with the sheet fed by the aforementioned feeding rotating body, A detachable attachment unit is provided detachably with respect to the separation unit, and the attachment unit has a sheet separation section that separates the sheets one by one together with the separation surface by contacting the sheets fed by the feeding rotating body, The direction perpendicular to the sheet feeding direction and the rotation axis direction of the feeding rotating body, the direction from the separation surface toward the feeding rotating body, is defined as the protruding direction. When the attachment / detachment unit is mounted on the separation portion, the seat separation portion is located downstream of the separation surface in the protruding direction. When the attachment / detachment unit is mounted on the separation portion, the portion of the attachment / detachment unit other than the seat separation portion does not come into contact with the seat fed by the feeding rotating body. A sheet feeding device characterized by the following features. (Composition 22) A sheet feeding device according to any one of configurations 1 to 21, The system comprises an image forming unit that forms an image on a sheet fed from the sheet feeding device, An image forming apparatus characterized by the following features. [Explanation of Symbols]

[0104] 1,1B: Image forming apparatus / 1A: Apparatus body / 12: Feeding and rotating body (pickup roller) / 11: Pull-out unit (cassette) / 50: Loading section (tray) / 60: Separation section (separation wall) / 60a: Separation surface (separation slope) / 60bL, 60bR: Third opening (opening) / 61L, 61R: Contact section / 62, 162: Detachable unit (sheet separation unit) / 62aL, 62aR: Contacted section (unit contact section) / 63: Sheet separation section / 63L: First sheet separation section (sheet separation section) / 63R: Second sheet Separation part (sheet separation part) / 64: Biasing member / 65L, 65R: Restricting member (holding member) / 66, 166, 266: Opening, first opening / 67, 167, 267: Cover / 67cL, 67cR: Second opening (opening) / 70L, 70R: Restricting member (locking member) / 80: Image forming part / 90: Sheet feeding device / 162aL, 162aR: Contact part (locking claw) / D1, D3, D4: Width / D2: Distance / FD: Sheet feeding direction / FE: One end / PD: Protruding direction / SE: Other end / W: Rotation axis direction (width direction)

Claims

1. The loading section where the sheets are loaded, A feeding rotating body that feeds the sheets loaded in the loading section toward the image forming section in the sheet feeding direction, A separation section having a separation surface arranged to be in contact with the sheet fed by the aforementioned feeding rotating body, A detachable attachment unit is provided detachably with respect to the separation unit, and the attachment unit has a sheet separation section that separates the sheets one by one together with the separation surface by contacting the sheets fed by the feeding rotating body, The direction perpendicular to the sheet feeding direction and the rotation axis direction of the feeding rotating body, the direction from the separation surface toward the feeding rotating body, is defined as the protruding direction. When the attachment / detachment unit is mounted on the separation portion, the seat separation portion is located downstream of the separation surface in the protruding direction. When the attachment / detachment unit is attached to the separation portion, the portion of the attachment / detachment unit other than the seat separation portion is located upstream of the separation surface in the protruding direction. A sheet feeding device characterized by the following features.

2. The separation portion has an opening into which the attachment / detachment unit, which is mounted to the separation portion, is inserted. The sheet feeding device according to feature 1.

3. The opening is open toward the downstream direction in the protruding direction. The sheet feeding device according to feature 2.

4. The opening is open toward the upstream direction in the protruding direction. The sheet feeding device according to feature 2.

5. The aforementioned opening is open in the vertical direction. The sheet feeding device according to feature 2.

6. The detachable unit has one end and the other end in the direction of the rotation axis, The sheet separation portion includes a first sheet separation portion provided in the direction of the rotation axis at a position closer to one end than the other end, and a second sheet separation portion provided in the direction of the rotation axis at a position closer to the other end than the one end, In the direction of the rotation axis, the width of the opening is longer than the distance between the first sheet separation portion and the second sheet separation portion. The sheet feeding device according to feature 2.

7. The system further includes a restricting member that prevents the detachable unit inserted into the opening from being removed from the separation portion. The sheet feeding device according to feature 2.

8. The restricting member is movable between a restricting position that restricts the removal of the detachable unit from the separation portion and a position that allows the removal of the detachable unit from the separation portion. The sheet feeding device according to feature 7.

9. The restricting member covers a portion of the opening at the restricting position and expands the opening area of ​​the opening by moving from the restricting position to the allowable position. The sheet feeding device according to feature 8.

10. The restricting member is removably fixed to the separation portion. The sheet feeding device according to feature 7.

11. The separation portion has a contact portion, The detachable unit has a contact portion that can contact the contact portion, The system further includes a biasing member that positions the detachable unit relative to the separation portion by biasing the detachable unit so that the contact portion contacts the contact portion while the detachable unit is mounted on the separation portion. The sheet feeding device according to feature 2.

12. The biasing member biases the detachable unit in the protruding direction when the detachable unit is attached to the separation portion. The contact portion is located upstream of the contact portion in the protruding direction when the detachable unit is attached to the separation portion. The sheet feeding device according to feature 11.

13. The attachment / detachment unit is movable upstream in the protruding direction against the biasing force of the biasing member when the sheet separation portion is pressed by the sheet fed by the feeding rotating body. The sheet feeding device according to feature 11.

14. The contact portion is locked to the contact portion when the detachable unit is inserted into the opening, thereby restricting the detachable unit from being removed from the separation portion. The sheet feeding device according to feature 11.

15. The aforementioned opening is further provided with a cover that can be opened and closed. The sheet feeding device according to feature 2.

16. The aforementioned opening is a first opening, The aforementioned cover has a second opening, The seat separation portion protrudes from the second opening in the protruding direction after the cover is closed following the insertion of the attachment / detachment unit into the first opening. The sheet feeding device according to feature 15.

17. The aforementioned opening is a first opening, The separation surface of the separation portion has a third opening, The seat separation portion protrudes from the third opening in the protruding direction after the cover is closed following the insertion of the attachment / detachment unit into the first opening. The sheet feeding device according to feature 15.

18. The cover is supported in the separation section so as to be openable and closable. The sheet feeding device according to feature 15.

19. At least a portion of the sheet separation section has a higher coefficient of friction than the separation surface. The sheet feeding device according to feature 1.

20. The main body of the device, The device further comprises a drawer unit that supports the loading section, the feeding and rotating body, the separation section, and the detachable unit, and is retractably mounted on the main body of the device. The sheet feeding device according to feature 1.

21. The loading section where the sheets are loaded, A feeding rotating body that feeds the sheets loaded in the loading section toward the image forming section in the sheet feeding direction, A separation section having a separation surface arranged to be in contact with the sheet fed by the aforementioned feeding rotating body, A detachable attachment unit is provided detachably with respect to the separation unit, and the attachment unit has a sheet separation section that separates the sheets one by one together with the separation surface by contacting the sheets fed by the feeding rotating body, The direction perpendicular to the sheet feeding direction and the rotation axis direction of the feeding rotating body, the direction from the separation surface toward the feeding rotating body, is defined as the protruding direction. When the attachment / detachment unit is mounted on the separation portion, the seat separation portion is located downstream of the separation surface in the protruding direction. When the attachment / detachment unit is mounted on the separation portion, the portion of the attachment / detachment unit other than the seat separation portion does not come into contact with the seat fed by the feeding rotating body. A sheet feeding device characterized by the following features.

22. A sheet feeding device according to any one of claims 1 to 21, The system comprises an image forming unit that forms an image on a sheet fed from the sheet feeding device, An image forming apparatus characterized by the following features.

Images