JP6429613B2 - Sheet feeding apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to a sheet feeding apparatus that feeds stacked sheets, and an image forming apparatus including the sheet feeding apparatus.

  2. Description of the Related Art Conventionally, image forming apparatuses such as copying machines, printers, and facsimiles include a sheet feeding device for supplying sheets to an image forming unit. The sheet feeding device is provided with sheet storage means for storing a sheet for feeding. As an example of the sheet storage means, a paper feed cassette that can be attached to and pulled out from the image forming apparatus can be cited.

  Here, in an image forming apparatus provided with such a sheet feeding cassette, a configuration in which the sheet feeding cassette is configured to be pulled out in the width direction orthogonal to the sheet conveying direction is known. As described above, when the paper cassette is pulled out in the width direction, the paper feeding cassette can be pulled out in front of the image forming apparatus main body (hereinafter also referred to as the apparatus main body). Therefore, when a paper jam (jam) or the like occurs, there is an advantage that the user does not have to go to the side of the apparatus for processing, and user access is easy.

  A typical method used for separating sheets in such a sheet separating section of a sheet feeding cassette is a separation roller method. As this separation roller type apparatus, one having a configuration for separating sheets using a separation roller that is not driven in reverse rotation is known (see Patent Document 1).

  In a sheet feeding apparatus that employs a separation roller method, it is necessary to place a separation roller (separation rotating body) close to the sheets stacked on the sheet feeding cassette, and the separation roller must be replaced. It needs to be easy. For this reason, the separation roller is often mounted on the paper feed cassette. On the other hand, a feeding roller (feeding rotator) facing the separation roller is disposed in the apparatus main body.

  Here, when the paper feed cassette is pulled out from the apparatus main body, it is necessary to retract the separation roller from the feed roller in order to prevent the separation roller and the feed roller from being rubbed and worn while being pulled out. . As a mechanism for retracting the separation roller, there has been proposed an apparatus having a configuration in which the casing supporting the separation roller and the separation spring is swung with respect to the paper feed cassette. In this apparatus, when the sheet feeding cassette is mounted on the apparatus main body, the separation roller moves in the direction of the feeding roller of the apparatus main body together with the casing and contacts the feeding roller (see Patent Document 2).

  The separation roller includes a roller body such as rubber, a separation roller shaft that supports the roller body, and a torque limiter that regulates reverse rotation of the separation roller shaft. When a torque exceeding the specified torque of the torque limiter is applied to the torque limiter during sheet feeding, a slip occurs between the torque limiter and the separation roller shaft, and the roller body rotates while both slide. The separation roller shaft is frictionally charged by rubbing both, but is neutralized by natural discharge over time before being charged again.

  Here, there has been proposed an apparatus that employs a method of positively eliminating static electricity instead of spontaneous discharge, and disposing a static elimination brush on the main body of the image forming apparatus so as to eliminate static electricity while feeding the pickup roller. In this apparatus, a static elimination member (static elimination brush) for removing static electricity charged on the pickup roller is fixedly supported on a frame for improving rigidity of the apparatus body that is electrically grounded (see Patent Document 3).

Japanese Unexamined Patent Publication No. 7-232831 JP 2009-1350 A JP 2008-24424 A

  By the way, according to the apparatus described in Patent Document 3, although it is possible to remove the charge while the pickup roller is being fed, it is difficult to apply to the above-described charge removal of the separation roller because of its structure. In recent years, downsizing and speeding up of the apparatus have been advanced, and for example, a small-diameter separation roller is frequently used at high rotation. As a result, the charge amount and charging frequency of the separating roller shaft during feeding increase, and the neutralization of the separating roller shaft cannot be satisfied only by natural discharge. As the charging of the separation roller shaft proceeds, a discharge is generated from the separation roller shaft during normal operation, so that noise may be added to the control signal and the image forming apparatus main body may malfunction.

  Further, when the charge amount of the separation roller shaft of the separation roller is increased, paper dust generated from the sheet being fed is attracted to the vicinity of the separation roller. As a result, when the paper feeding cassette is stored in the apparatus main body, the movement of the separation roller in the casing is hindered by the sucked paper powder, and the separation roller is inclined and abuts against the feeding roller of the apparatus main body. There is a fear. When the separation roller is in contact with the feeding roller at an angle, the sheet cannot be properly conveyed from the sheet feeding cassette, and there is a possibility of causing a conveyance failure such as a paper jam or skew. In addition, uneven wear occurs on the surface of the separation roller, which may reduce the separation performance.

  According to Patent Document 3, since the neutralizing brush is installed in the apparatus main body, paper dust accumulated on the paper feeding cassette is scraped up by the neutralizing brush when the paper feeding cassette is mounted and pulled out. Then, when the paper feeding cassette is inserted again, the paper dust scraped by the static elimination brush enters the separation roller casing, and the above-described problem may occur. In addition, when a paper jam occurs in the feeding unit, the paper cassette is loaded and unloaded with the sheet bent and deformed on the separation roller. As a result, problems such as impaired durability may occur.

  Accordingly, the present invention provides a sheet feeding apparatus that does not cause inconveniences such as noise discharge from the separation rotator due to frictional charging or loss of feeding performance or separation performance in a configuration in which the sheet storage means includes the separation rotator. An object is to provide an image forming apparatus.

  In the sheet feeding apparatus, the present invention is provided in the apparatus main body electrically grounded, provided in the apparatus main body so as to be attached to and withdrawn from the apparatus main body, and in the apparatus main body. A sheet feeding rotary member that feeds a sheet from the sheet storage unit, and a sheet that is provided in the sheet storage unit and is conveyed by the sheet feeding unit is formed by contact with the sheet feeding rotary unit. A separation rotator that separates and conveys one sheet at a time in the separation nip portion and the sheet storage means, and the separation rotator is attached to the feeding rotation body when the sheet storage means is attached to and pulled out from the apparatus main body. Conductive support means having conductivity and supporting so as to be able to come into contact with and separate from each other, and the conductive support means provided in the apparatus main body, when the sheet storage means is attached to the apparatus main body It is moved toward the feeding rotary body, wherein the separation rotating member, characterized in that it comprises a contact conducting means for conducting the device main body is brought into contact with the feeding rotary member.

  According to the present invention, in the configuration in which the sheet storage unit includes the separation rotating body, the sheet feeding apparatus does not cause inconveniences such as noise discharge from the separation rotating body due to frictional charging, and loss of feeding performance and separation performance. In addition, an image forming apparatus can be provided.

1 is a cross-sectional view illustrating a schematic configuration of an image forming apparatus equipped with a sheet feeding device according to an embodiment of the present invention. FIG. 2A is a schematic cross-sectional view of a sheet feeding apparatus according to an embodiment, and FIG. 2B is a perspective view schematically illustrating a separating unit of the sheet feeding apparatus. (A) is a perspective view showing the separation unit according to this embodiment as seen from the outside, (b) is a perspective view showing the separation unit of (a) as seen from the inside, and (c) is (a). The side view shown in the state which looked at the separation unit from the near side. The disassembled perspective view shown in the state which decomposed | disassembled the structure of the separation roller which concerns on this embodiment. (A) is a perspective view showing a state in which the paper feed cassette according to the present embodiment is pulled out, (b) is a perspective view showing a state of the paper feed cassette and the rail when the paper feed cassette is pulled out, (c) is a perspective view. The perspective view which shows the state of the rail part at the time of pulling out a paper feed cassette. Sectional drawing which shows the separation unit at the time of pulling out the paper feed cassette concerning this embodiment. (A) is a side view showing the positional relationship between the separation unit and the rail portion immediately before the completion of mounting the paper feed cassette according to the present embodiment, and (b) is the separation unit and rail portion immediately before the completion of mounting of the paper feed cassette. Sectional drawing which shows positional relationship with. (A) is a figure which shows the state at the time of inserting the paper feed cassette which concerns on this embodiment, (b) is a side view which shows the state at the time of inserting a paper feed cassette. (A) is a figure which shows the state which completed mounting | wearing of the paper feed cassette which concerns on this embodiment, (b) is a side view which shows the state which completed mounting | wearing of the paper feed cassette. (A) is a schematic perspective view which shows the separation means of the sheet feeding apparatus which concerns on 2nd Embodiment, (b) is a schematic perspective view which shows the separation means of the sheet feeding apparatus which concerns on 3rd Embodiment.

<First Embodiment>
Hereinafter, an electrophotographic image forming apparatus such as a copying machine or a printer, and a sheet feeding apparatus mounted on the image forming apparatus will be described as an example with reference to the drawings.

[Entire configuration of image forming apparatus]
First, the overall configuration of the image forming apparatus will be described with reference to FIG. FIG. 1 is a cross-sectional view showing a schematic configuration of an image forming apparatus 50 such as a full-color laser beam printer equipped with a sheet feeding apparatus 70 according to this embodiment.

  As shown in FIG. 1, the image forming apparatus 50 roughly includes an image forming unit 58, a sheet feeding device 70, a sheet conveying unit, a fixing device 30, a sheet discharging unit 40, and a power supply unit 200. In the image forming apparatus 50, an image forming unit 58 is provided at the center, a feeding / conveying unit is disposed from the lower right hand to the upper right hand toward the front, and the fixing device 30 is disposed at the uppermost right hand.

  The image forming apparatus 50 includes an image forming apparatus main body (hereinafter referred to as an apparatus main body) 50a. The apparatus main body 50a is provided with a main body frame made of a conductive member, and is provided with a storage space Sp in which the paper feed cassette 71 can be stored, and four photosensitive drums 1 (1a) arranged in parallel in the horizontal direction. , 1b, 1c, 1d). The photosensitive drum 1 is supported by a driving means (not shown) so as to be driven to rotate in the clockwise direction in FIG. The apparatus main body 50a is provided with a control unit 55 as a control unit having a CPU, a RAM, and a ROM for controlling each unit.

  In addition, the electroconductive member in this embodiment is comprised from the metal material or the resin material which reduced resistance value by giving the process of kneading carbon or vapor-depositing metal foil on the surface.

  Around the photosensitive drum 1, the charging roller 2 (2a, 2b, 2c, 2d), the scanner unit 3 (3a, 3b, 3c, 3d), and the developing device 4 (4a, 4b, 4c, 4d) and an intermediate transfer belt unit 5 are arranged. Further, a belt cleaning device 8, a waste toner conveying device 19 and a recovery container 10, a drum cleaning device 6 (6a, 6b, 6c, 6d) and the like are arranged. Reference numeral 8a denotes a toner scraping member of the belt cleaning device 8, 8b denotes a toner conveying screw, and 8c denotes a casing.

  The charging roller 2 (2a, 2b, 2c, 2d) uniformly charges the surface of the photosensitive drum 1. The scanner unit 3 (3a, 3b, 3c, 3d) irradiates a laser beam based on the image information to form an electrostatic latent image on the photosensitive drum. The developing device 4 (4a, 4b, 4c, 4d) develops a toner image by attaching toner to the electrostatic latent image. The intermediate transfer belt unit 5 transfers the toner image on the photosensitive drum.

  The cleaning device 8 removes toner remaining on the surface of the intermediate transfer belt 11 (hereinafter referred to as waste toner). The waste toner transport device 19 and the collection container 10 transport the waste toner WT discharged from the cleaning device 8. The cleaning device 6 (6a, 6b, 6c, 6d) removes the transfer residual toner remaining on the surface of the photosensitive drum 1 after the transfer.

  The scanner unit 3 is disposed below the photosensitive drum 1, and image light corresponding to an image signal is rotated at high speed by a scanner motor (not shown) by a laser diode (not shown). 9c, 9d).

  Each of the developing devices 4a, 4b, 4c, and 4d is composed of a developing device that stores toner of each color of yellow, magenta, cyan, and black, respectively.

  The intermediate transfer belt unit 5 includes transfer rollers 12a, 12b, 12c, and 12d facing the photosensitive drums 1a, 1b, 1c, and 1d, and an intermediate transfer belt 11 supported in the horizontal direction by biaxial rollers. ing. A secondary transfer roller 21 is disposed at the right end portion of the intermediate transfer belt 11 with a predetermined pressure through a conveyance path.

  The sheet feeding device 70 feeds and conveys the sheet S toward the image forming unit 58. The sheet feeding device 70 stores a plurality of sheets S, the pickup roller 18, the feeding roller 14, and the like. And a separation roller 81. A registration roller pair 20 that conveys the separated sheet S is disposed downstream of the sheet feeding device 70 in the conveyance direction.

  A power supply unit 200 is disposed in the lower part of the apparatus main body 50a. The power supply unit 200 is housed in a casing made of a conductive member, and is fastened and conducted to a main body frame of the apparatus main body 50a made of a conductive member. A power cord is connected to the power supply unit 200, and one end of the power cord is electrically connected to the ground through an inlet or the like at the installation place of the image forming apparatus 50 and grounded (grounded). As described above, the apparatus main body 50 a of the image forming apparatus 50 is electrically grounded via the power supply unit 200.

[Image forming operation]
Next, an image forming operation will be described. First, the process cartridges 7a, 7b, 7c, and 7d are sequentially driven in accordance with the printing timing, and the photosensitive drums 1a, 1b, 1c, and 1d are rotationally driven in the clockwise direction in accordance with the drive. Then, the scanner units 3 corresponding to the respective process cartridges 7 are sequentially driven.

  By this driving, the charging roller 2 imparts a uniform charge to the circumferential surface of the photosensitive drum 1, and the scanner unit 3 exposes the circumferential surface of the photosensitive drum 1 according to an image signal to perform the circumferential surface of the photosensitive drum 1. An electrostatic latent image is formed thereon. The developing roller in the developing device 4 forms (develops) a toner image on the circumferential surface of the photosensitive drum by transferring the toner to the low potential portion of the electrostatic latent image.

  When the feeding operation is started by the sheet feeding device 70, the sheet S is fed out by the pickup roller 18 and fed downstream in the feeding direction by the feeding roller 14. The fed sheet S is conveyed by the registration roller pair 20 with its inclination with respect to the conveyance direction corrected.

  The toner image on each photosensitive drum 1 is sequentially transferred onto the intermediate transfer belt 11 by an electric field formed between each photosensitive drum 1 and the transfer roller 12. Thereafter, the toner image transferred onto the intermediate transfer belt 11 is subjected to secondary transfer onto the conveyed sheet by an electric field formed at the secondary transfer nip N2 between the intermediate transfer belt 11 and the secondary transfer roller 21. Is done.

  The sheet S to which the four color toner images have been transferred is carried into the fixing device 30, and the toner image is thermally fixed by the fixing device 30, and then conveyed by the discharge roller pair 31. The sheet S is partially discharged by a discharging member (not shown) immediately after being discharged from the discharge roller pair 32 and then discharged to the sheet discharging unit 40. The image forming unit 58 that forms an image on the sheet S fed from the sheet feeding device 70 is configured by the image forming unit 58, the secondary transfer nip N2, and the fixing device 30.

[Configuration of sheet feeding device]
Next, a schematic configuration of the sheet feeding apparatus 70 will be described with reference to FIGS. 2A and 2B, FIGS. 3A to 3C, and FIG. 2A is a schematic cross-sectional view of the sheet feeding apparatus 70 according to the present embodiment, and FIG. 2B is a perspective view schematically illustrating a separating unit of the sheet feeding apparatus 70. 3A is a perspective view showing the separation unit 80 as seen from the outside, FIG. 3B is a perspective view showing the separation unit 80 in FIG. 3A as seen from the inside, FIG. (C) is side sectional drawing which shows the state which looked at the isolation | separation unit of Fig.3 (a) from the near side. FIG. 4 is an exploded perspective view showing the configuration of the separation roller 81 according to the present embodiment in an exploded state.

  As shown in FIGS. 2A and 2B, the sheet feeding device 70 is stored in the sheet feeding cassette 71 and a sheet feeding cassette 71 configured to stack sheets S and be able to be pulled out from the apparatus main body 50 a. And a pickup roller 18 for feeding out the sheet S. Further, the sheet feeding device 70 includes a feeding roller 14 that feeds the sheet S fed by the pickup roller 18 downstream. The sheet feeding cassette 71 is provided so as to be able to be attached to and pulled out from the apparatus main body 50a, and constitutes a sheet storing means for storing the sheet S. The feeding roller 14 is composed of a rubber roller, and is disposed on the downstream side of the pickup roller 18. The feeding roller 14 is provided in the apparatus main body 50 a and constitutes a feeding rotating body that feeds the sheet S from the sheet feeding cassette 71.

  The sheet feeding cassette 71 includes a cassette body 72 which is a frame, a sheet stacking plate 73 on which sheets S are stacked, a lifter 74, side restricting plates 75 and 76, a rear end restricting plate 77, and a separation unit 80. have. The side regulating plates 75 and 76 regulate the position in the width direction of the stacked sheets S. The side regulating plates 75 and 76 are supported to be movable in accordance with the lateral width of the sheet S by a user operation. When the side regulating plates 75 and 76 abut against the side surfaces of the stacked sheets S, the positions of the sheet end portions are aligned.

  The trailing edge regulating plate 77 is a member that regulates the trailing edge position of the stacked sheets S. The rear end regulating plate 77 is configured to be movable by a user operation from the rear side of the cassette body 72 toward the separation unit 80. The rear end regulating plate 77 abuts the rear end of the stacked sheets S and aligns the rear ends thereof, and moves the sheet S so that the front end thereof abuts on the front end surface 78 of the cassette body 72. Align.

  As shown in FIGS. 3A to 3C, the separation unit 80 includes a separation roller 81, a separation roller holder 82, a cover 83, a nip guide 84, a separation spring 85, a separation lever 86, a separation spring 87, and a ground plate. 88. The separation unit 80 is configured to be detachably supported with respect to the cassette body 72 of the paper feed cassette 71.

  The separation roller 81 is provided in the sheet feeding cassette 71 and separates and conveys the sheet S conveyed by the feeding roller 14 one by one at a separation nip portion N formed by contact with the feeding roller 14. A separate rotating body is configured. The separation unit 80 is provided in the paper feed cassette 71 and supports the separation roller 81 so that it can come into contact with and separate from the feed roller 14 when the paper feed cassette 71 is attached to and pulled out from the apparatus main body 50a. This constitutes a conductive support means having conductivity. When the sheet feeding cassette 71 is attached to the apparatus main body 50a, the separation unit 80 allows the separation roller 81 to be electrically connected to the grounded apparatus main body 50a via the engaging projection 93 of the rail portion 96 (FIG. 5). it can.

  Here, FIG. 4 is an exploded perspective view showing the structure of the separation roller 81 according to the present embodiment in an exploded state. As shown in FIG. 4, the separation roller 81 includes a roller body 81a, a roller housing 81b, a separation roller shaft 81c, a coil spring 81d, and a cap 81e.

  The separation roller 81 is supported at both ends of the separation roller shaft 81c by support holes (not shown) of the separation roller holder 82 in a state where the rotation is restricted via the D-cut surface 81f of the separation roller shaft 81c. The separation roller holder 82 is made of a conductive member, and as shown in FIGS. 3A to 3C, has a protruding portion 82a protruding in a shaft shape at both ends of the upper shaft portion 82b. In the separation roller holder 82, the protrusions 82a at both ends of the shaft portion 82b are rotatably engaged with holes 83a formed in the cover 83, respectively, and the separation roller holder 82 supporting the separation roller 81 and the cover 83 together. So that it can swing.

  As described above, the separation roller 81 of the present embodiment has the separation roller shaft 81c, the roller housing 81b, the roller body 81a, and the coil spring 81d, and the separation roller shaft 81c has both ends thereof as the separation roller holder 82. Fixedly supported. The roller housing 81b is rotatably fitted to the separation roller shaft 81c, and the roller body 81a is non-rotatably fitted to the roller housing 81b.

  The roller housing 81b has a locking portion 81g on the inner peripheral surface of one end portion, and one end portion 81h of a coil spring 81d fitted to the separation roller shaft 81c is locked to the locking portion 81g. The coil spring 81d is interposed between the separation roller shaft 81c and the roller housing 81b. The coil spring 81d constitutes a torque limiter that expands its inner diameter and allows the roller housing 81b to rotate relative to the separation roller shaft 81c when a predetermined or greater rotational torque in the sheet feeding direction acts on the roller housing 81b.

  Further, as shown in FIGS. 3A to 3C, a protrusion 82c is formed on the lower surface of the separation roller holder 82, and a compression spring that urges the separation roller holder 82 upward is formed. A separating spring 85 is provided to be contracted. The separation spring 85 is composed of a conductive member, and its lower end is supported so as to abut against a ground plate 88 composed of a conductive member engaged with the rib 83 d of the cover 83.

  A separation lever 86 made of a conductive member is disposed below the rib 83 d that is formed to protrude from the inner surface of the cover 83. The separation lever 86 integrally includes a lever portion 86 a, a rotation stop rib 86 b, and an abutment rib 86 c, and both ends thereof are rotatably supported by the rib 83 e of the cover 83.

  On the cover 83 side of the lever portion 86a, a separation spring 87 that urges the lever portion 86a toward the front side in FIG. As shown in FIG. 3 (c), a bent portion 88 a bent downward at a predetermined angle is provided at the tip of the ground plate 88, and this bent portion 88 a is provided at the upper rear end of the separation lever 86. It abuts on the provided ridgeline portion 86d.

  The separation roller holder 82 provided in the separation unit 80 includes a separation rotating body holding portion that supports the separation roller 81 so as to be in contact with and separated from the feeding roller 14 when the sheet feeding cassette 71 moves along the rail portion 96. It is composed. Further, the separation lever 86 constitutes an engaged portion that engages with the engaging convex portion 93 when the paper feeding cassette 71 is moved, thereby bringing the separation roller 81 into contact with the feeding roller 14 via the separation roller holder 82. To do.

  The engaging convex portion 93 is provided on the apparatus main body 50 a, moves the separation unit 80 toward the feeding roller 14 when the paper feeding cassette 71 is mounted on the apparatus main body 50 a, and moves the separation roller 81 to the feeding roller 14. An abutting conduction means for abutting and conducting to the apparatus main body 50a is configured. For this reason, the engaging convex portion 93 as the contact conduction means only moves over the abutment rib 86c of the separation unit 80 moving along the longitudinal direction of the rail portion 96, and the separation roller 81 is fed to the feeding roller. 14 can be surely brought into contact with each other and can be reliably discharged.

[Configuration near the sheet feeding device]
Next, with reference to FIGS. 5A to 5C, a configuration in the vicinity of the sheet feeding device 70 disposed on the lower side in the apparatus main body 50 a in the image forming apparatus 50 will be described. 5A is a perspective view showing a state in which the paper feed cassette 71 according to this embodiment is pulled out from the apparatus main body 50a, and FIG. 5B is a state in which the paper feed cassette 71 is pulled out from the apparatus main body 50a. It is a perspective view which shows the paper feed cassette 71 and the rail parts 90 and 96 in FIG. FIG. 5C is a perspective view showing only the rail portions 90 and 96 in a state in which the paper feed cassette 71 is pulled out from the apparatus main body 50a.

  As shown in FIGS. 5A to 5C, the rail portions 90 and 96 are each configured to be extendable and guide the attachment and withdrawal of the paper feed cassette 71 with respect to the image forming apparatus 50. The rail portion 90 is disposed on the rear end regulating plate 77 side of the paper feed cassette 71, and the rail portion 96 is disposed on the separation unit 80 side. The rail portion 90 includes an outer rail 91 fixed to the apparatus main body 50 a and an inner rail 92 that is pulled out from the outer rail 91 together with the paper feed cassette 71. The rail portion 96 includes an outer rail 97 fixed to the apparatus main body 50 a and an inner rail 98 that is pulled out from the outer rail 97 together with the paper feed cassette 71. The outer rail 97 of the rail portion 96 has an engaging convex portion (contact conduction means) 93 that is formed in a trapezoidal shape at a predetermined position (substantially central portion).

  The rear end portion 94 of the outer rail 97 is inserted into a main body frame (not shown) of the apparatus main body 50a, and is screwed and fixed to the main body frame by screwing the tab 95 at the other end. A main body frame (not shown) of the apparatus main body 50a is electrically connected to the ground and grounded through the power source 200, a casing of the power source 200, and a power cable (not shown). Thereby, the outer rail 97 fastened to the main body frame is also electrically connected to the ground (grounded).

  The rail portion 96 is electrically connected to the apparatus main body 50 a, and constitutes guide means having an engaging convex portion (contact conductive means) 93 while moving and guiding the paper feed cassette 71 to the apparatus main body 50 a. As a result, the rail 96 can reliably contact the feeding roller 14 with the separation roller 81 only by getting over the engaging projection 93 of the abutment rib 86c of the separation unit 80 moving along the longitudinal direction. It is possible to reliably remove static electricity while making contact.

[Feeding operation by sheet feeding device]
Next, the feeding operation by the sheet feeding device 70 will be described with reference to FIGS. FIG. 6 is a side sectional view showing the separation unit 80 in a state in which the paper feed cassette 71 is pulled out from the apparatus main body 50a. FIG. 7A is a side view showing the positional relationship between the separation unit 80 and the outer rail 97 immediately before the paper feed cassette 71 is completely attached to the apparatus main body 50a. FIG. 7B is a cross-sectional view showing the positional relationship between the separation unit 80 and the rail portion immediately before the paper feed cassette 71 is completely attached to the apparatus main body 50a.

  As shown in FIGS. 6 and 7A and 7B, the separation lever 86 has the protrusion 82 a as a fulcrum until the abutting rotation stopper rib 86 b hits the inner surface of the cover 83 due to the biasing force of the separation spring 87. It can be rotated. The distal end of the lever portion 86 a of the separation lever 86 abuts against a protrusion 82 c that protrudes obliquely forward from the lower portion of the separation roller holder 82, and the separation roller holder 82 against the cover 83 against the urging force of the separation spring 85. To hold the state rotated by a predetermined angle.

  As described above, the separation roller holder 82 urges the separation roller 81 in the approaching direction approaching the feeding roller 14 while being rotatably held. Further, the separation lever 86 is biased in a regulation direction that regulates the approaching operation of the separation roller holder 82 to the feeding roller 14, and when the sheet feeding cassette 71 is engaged with the engagement convex portion 93, the direction opposite to the regulation direction. To release the separation roller holder 82 and move it in the approaching direction. With this configuration, the separation roller holder 82 is deregulated only by rotating the separation lever 86 by the engagement of the abutment rib 86 c and the engagement convex portion 93, and the separation roller 81 is securely attached to the feeding roller 14. It becomes possible to contact.

  Here, when the user sets a sheet in the drawn paper cassette 71 and inserts the paper cassette 71 into the apparatus main body 50a, the following occurs. That is, when the sheet feeding cassette 71 is inserted into the apparatus main body 50a, the abutment rib 86c of the separation lever 86 comes into contact with the upper surface of the outer rail 97, and the separation lever 86 maintains a posture rotated at a predetermined angle. Since the position of the lever portion 86a of the separation lever 86 is rotated from the state of FIG. 6, the separation roller holder 82 is also slightly rotated with respect to the cover 83 from the state of FIG. 6 via the lever portion 86a.

  In this state, the separation roller 81 supported by the separation roller holder 82 is in a position retracted downward from the upper surface portion of the separation roller holder 82 as shown in FIG. Therefore, the separation roller 81 does not come into contact with the feed roller 14 in the process of inserting the paper feed cassette 71 into the apparatus main body 50a.

  8A and 8B show a halfway state when the paper feed cassette 71 is inserted into the apparatus main body 50a, and FIGS. 9A and 9B show a state where the mounting is completed. That is, when the abutment rib 86c of the separation lever 86 starts to climb up the engagement convex portion 93 of the outer rail 97 as shown in FIGS. 8A and 8B, the separation lever 86 biases the separation spring 87. It further rotates against this and approaches the inner surface of the cover 83. As a result, the separation roller 81 comes close to the feeding roller 14.

  When the paper feeding cassette 71 is further inserted into the storage space Sp of the apparatus main body 50a, the abutment rib 86c reaches the top of the engaging convex portion 93 as shown in FIGS. 9 (a) and 9 (b). . Therefore, the separation lever 86 rotates to a position away from the protrusion 82c of the separation roller holder 82 via the lever portion 86a. In this state, the separation roller 81 completes contact with the feeding roller 14 by the spring pressure of the separation spring 85. Thereafter, under the control of the control unit 55 (see FIG. 1) provided in the apparatus main body 50a, the sheet stacking plate 73 is lifted to the lifter 74 with the sheets S placed thereon, and the sheets S stacked on the sheet stacking plate 73 are picked up. It is made to contact | abut to the roller 18 (refer Fig.2 (a)).

  Next, an operation when a feeding instruction is output from the control unit 55 and a feeding operation is started will be described with reference to FIG.

  First, when a feeding instruction is output from the control unit 55 and a feeding operation is started, the pickup roller 18 is rotated counterclockwise (in the direction of arrow A in FIG. 2A) by a driving source (not shown). . As a result, the uppermost sheet S 1 of the sheets S stacked on the sheet stacking plate 73 in the sheet feeding cassette 71 is fed out to the nip portion N between the feeding roller 14 and the separation roller 81.

  At this time, when a plurality of sheets S are fed out to the nip portion N between the feeding roller 14 and the separation roller 81, only the uppermost sheet S 1 is conveyed by the rotation of the feeding roller 14, and the separation roller 81. A frictional force acts between the conveyed sheet S1 and the sheet below it. Since the acting frictional force is smaller than the force with which the coil spring 81d shown in FIG. 4 is tightened against the separation roller shaft 81c, the inner diameter of the coil spring 81d cannot be expanded. Therefore, no slip occurs between the coil spring 81d and the separation roller shaft 81c, and the roller body 81a and the housing 81b do not rotate relative to the separation roller shaft 81c during sheet conveyance.

  On the other hand, when only one sheet S is introduced into the nip portion N between the feeding roller 14 and the separation roller 81, the separation roller 81 passes through the sheet S that is driven by the rotation of the feeding roller 14. A large rotational torque greater than a predetermined value acts on the roller body 81a. Therefore, a force acts on the coil spring 81d so that its inner diameter opens through the housing 81b, the frictional force between the coil spring 81d and the separation roller shaft 81c decreases, and the housing 81b, the coil spring 81d, and the cap 81e are separated by the separation roller. It slides and rotates with respect to the shaft 81c.

  In the present embodiment, the separation roller shaft 81c of the separation roller 81 is triboelectrically charged due to friction with the three components during sheet feeding to generate electric charges. However, the electric charge generated by this charging is applied to the outer rail grounded to the main body frame of the apparatus main body 50a through the separation roller holder 82, the separation spring 85, the ground plate 88 and the separation lever 86 which are made of a conductive member. Move to 97.

  Accordingly, the charge generated during the feeding of the separation roller 81 to the separation roller shaft 81c is always removed, and no charge is accumulated on the separation roller shaft 81c. Therefore, the apparatus main body 50a caused by the discharge at the separation roller 81 is eliminated. Can be reliably prevented. In addition, paper dust does not accumulate on the separation roller 81 and the like during feeding and when the paper feed cassette 71 is mounted and pulled out, and it is possible to prevent a decrease in separation performance and conveyance failure.

  In other words, according to the present embodiment, in the configuration in which the sheet feeding cassette 71 includes the separation roller 81, the separation roller 81 is not always charged and charged during sheet feeding, so that discharge noise is generated. I will not let you. Accordingly, it is possible to reliably prevent the occurrence of inconvenience such as malfunction on the apparatus main body side. Further, when the paper feeding cassette 71 is moved relative to the apparatus main body 50a, the paper powder accumulated in the apparatus main body does not adhere to the retracted separation roller 81, and the sheet feeding from the paper feeding cassette 71 does not occur. It is possible to prevent the occurrence of feeding failure such as paper jam or skew feeding. Accordingly, it is possible to provide the sheet feeding apparatus 70 and the image forming apparatus 50 that do not cause inconveniences that impair the feeding performance and separation performance.

<Second Embodiment>
Next, a sheet feeding apparatus 70 according to a second embodiment of the present invention will be described with reference to FIG. In the present embodiment, members that are functionally common with those of the first embodiment are denoted by the same reference numerals, and descriptions of components having the same configuration and function are omitted.

  That is, in the first embodiment, the configuration example in which the separation roller 81 is brought into contact with and separated from the feeding roller 14 when the paper feeding cassette 71 is mounted and pulled out is shown. In this embodiment, FIG. As described above, the ground plate 88 of the first embodiment is omitted.

  In the present embodiment, the separation roller holder (separation rotator holding portion) 82 holds the separation roller (separation rotator) 81 rotatably and is separated from the feed roller (feed rotator) 14 at a separation spring. (Biasing means) 85 is held. When the abutment rib 86 c rides on the engagement convex portion 93, the separation lever (engaged portion) 86 pushes the separation roller holder 82 through the separation spring 85, thereby causing the separation roller 81 to feed the feeding roller 14. Abut.

  According to the present embodiment, substantially the same effect as that of the first embodiment can be obtained, and the separation unit 80 is configured by omitting the ground plate 88 and the like in the first embodiment, thereby further simplifying the configuration. Can be expected to reduce costs.

<Third Embodiment>
Next, a sheet feeding apparatus 70 according to a third embodiment of the present invention will be described with reference to FIG. Also in this embodiment, members that are functionally common to those of the first embodiment are denoted by the same reference numerals, and descriptions of components having the same configuration and function are omitted.

  In other words, in the present embodiment, as shown in FIG. 10B, the separation spring (biasing means) 85 has a spring hooking portion (engaged portion) 85a that protrudes from the lower side thereof. A support plate 56 having a through long hole portion 56 a is fixed to the inner surface of the cover 83. A separation spring 85 whose upper part is in contact with the lower part of the separation roller holder 82 is supported by the support plate 56 with its spring hooking part 85a protruding from the through long hole part 56a. In the present embodiment, the spring hooking portion 85a of the separation spring 85 has the same function as the abutment rib 86c of the separation lever 86 in the first embodiment.

  In the present embodiment, the separation roller holder (separation rotating body holding portion) 82 holds the separation roller 81 rotatably and holds the separation roller 81 via a separation spring 85 at a position separated from the feeding roller 14. When the spring hooking portion 85a, which is the tip of the separation spring 85, is engaged with the engagement convex portion 93, the separation roller holder 82 is pushed in via the separation spring 85, thereby bringing the separation roller 81 into contact with the feeding roller 14. .

  According to this embodiment, substantially the same effect as that of the first embodiment can be obtained, and the separation unit 80 is configured by omitting the ground plate 88 and the separation lever 86 in the first embodiment. The cost can be expected to be further simplified.

  14 ... feed roller (feed rotating body) / 50 ... image forming apparatus / 50a ... main body / 57 ... image forming means / 70 ... sheet feeding apparatus / 71 ... sheet feeding cassette (sheet storage means) / 80 ... separation Unit (conductive support means) / 81 Separation roller (separation rotating body) / 81a Roller body / 81b Roller housing / 81c Separation roller shaft / 81d Coil spring / 82 Separation roller holder (separation rotation body holding part) / 85 ... Separation spring (biasing means) / 85a ... Spring hooking part (engaged part, tip part of biasing means) / 86 ... Separation lever (engaged part) / 93 ... Engaging convex part (contact) Conducting means) / 96 ... Rail part (guide means) / 200 ... Power supply part (grounded part of the apparatus body) / N ... Separation nip part / S ... Sheet / Sp ... Storage space

Claims (8)

An electrically grounded device body;
A sheet storage means that is provided so as to be capable of being attached to and pulled out from the apparatus main body, and stores a sheet;
A feeding rotating body that is provided in the apparatus main body and feeds a sheet from the sheet storing means;
A separation rotator that is provided in the sheet storage means and separates and conveys the sheet conveyed by the feeding rotator one by one at a separation nip portion formed by contact with the feeding rotator; and
Provided in the sheet storage means, and supports the separation rotator so that it can come into contact with and separate from the feeding rotation body when the sheet storage means is attached to and pulled out from the apparatus main body, and has conductivity. Conductive support means;
Provided in the apparatus main body, when the sheet storage means is mounted on the apparatus main body, the conductive support means is moved toward the feeding rotary body, and the separation rotary body is brought into contact with the feeding rotary body And a contact conduction means for conducting to the apparatus main body,
A sheet feeding apparatus characterized by that. A guide means which is electrically connected to the apparatus main body and guides the sheet storage means to move to the apparatus main body and has the contact conductive means;
The conductive support means conducts the separation rotating body through the contact conduction means of the guide means when the sheet storage means is mounted on the apparatus main body.
The sheet feeding apparatus according to claim 1. The guide means is a rail portion having the contact conduction means as an engaging convex portion,
The conductive support means includes
A separation rotator holding portion that supports the separation rotator so that the separation rotator can be brought into contact with and separated from the feeding rotator when the sheet storage means moves along the rail portion;
The separation rotating body holding portion is conducted, and the separation rotating body holding portion is moved by engaging the engaging convex portion when the sheet storage means is moved, so that the separation rotating body contacts the feeding rotation body. An engaged portion to be contacted,
The sheet feeding apparatus according to claim 2, wherein the sheet feeding apparatus is a sheet feeding apparatus. The separation rotator holding unit is configured to urge the separation rotator in an approaching direction to approach the feeding rotator by holding the separation rotator rotatably.
The engaged portion is biased in a regulating direction that regulates the approaching operation of the separation rotating body holding unit to the feeding rotating body, and when engaged with the engaging convex portion, the engaged portion is in a direction opposite to the regulating direction. Move to release the separation rotor holding part and move in the approaching direction;
The sheet feeding apparatus according to claim 3. The separation rotator holding unit rotatably holds the separation rotator and holds the separation rotator at a position spaced from the feeding rotation body via an urging unit,
When the engaged portion engages with the engaging convex portion, the separation rotating body is pressed against the feeding rotation body by pushing the separation rotating body holding portion through the biasing means.
The sheet feeding apparatus according to claim 3. The separation rotator holding unit rotatably holds the separation rotator and holds the separation rotator at a position spaced from the feeding rotation body via an urging unit,
The engaged portion is a tip portion of the urging means, and when engaged with the engaging convex portion, the separation rotator holding portion is pushed through the urging means to supply the separation rotator. Abutting against the rotating body,
The sheet feeding apparatus according to claim 3. The separation rotating body is
A separation roller shaft fixed at both ends to the conductive support means;
A roller housing rotatably fitted to the separation roller shaft;
A roller body non-rotatably fitted to the roller housing;
It is interposed between the separation roller shaft and the roller housing. When a rotational torque exceeding a predetermined value in the sheet feeding direction acts on the roller housing, the inner diameter is expanded to allow the roller housing to rotate with respect to the separation roller shaft. A coil spring;
The sheet feeding device according to claim 1, wherein the sheet feeding device is a sheet feeding device. A sheet feeding device according to any one of claims 1 to 7,
Image forming means for forming an image on the sheet fed from the sheet feeding device,
An image forming apparatus.

Images