JP5991582B2 - Sheet separating apparatus, sheet feeding apparatus, and image forming apparatus - Google Patents

Description

  The present invention relates to a sheet separating apparatus used in an image forming apparatus such as a printer, a facsimile machine, and a copying machine, a sheet feeding apparatus including the sheet separating apparatus, and an image forming apparatus including the sheet feeding apparatus. is there.

  2. Description of the Related Art Conventionally, an image forming apparatus having a sheet feeding device that feeds a sheet bundle that is fed from a sheet bundle stacked on a sheet feeding tray by a feeding roller and separated into only one sheet by a sheet separating device to an image forming unit is known. It has been.

  A sheet separating device provided in a sheet feeding device described in Patent Document 1 separates a sheet at a nip between a conveying roller that conveys the sheet in the feeding direction and a conveying roller provided below the conveying roller. And a separation roller.

  The separation roller is held via a rotating shaft by a holding member that is swingably attached to the bearing member, and can be contacted and separated while maintaining a parallel relationship with the conveying roller. Further, the holding member is biased by a spring that is stretched between the holding roller and the bearing member in the vicinity of the separation roller, and the holding member swings in a contact direction in which the separation roller comes into contact with the conveying roller. Thus, the separation roller is brought into contact with the conveying roller with a predetermined pressure.

  In addition, the separation member for separating the separation roller from the conveying roller can be engaged with and disengaged from the protrusion formed on the portion of the holding member opposite to the separation roller in the axial direction of the separation roller. And is rotatably supported. Then, the separation member engages with the protrusion and pushes down the holding member so as to swing in the separation direction to separate the separation roller from the conveyance roller against the biasing force of the spring, so that the separation roller is conveyed. Separate from the roller. In this way, by separating the conveyance roller and the separation roller, the sheet is damaged when the sheet is separated between the conveyance roller and the separation roller while the sheet is being separated and the sheet feeding tray is pulled out from the apparatus main body. It is said that it can be suppressed.

  However, when the conveying roller and the separation roller are separated from each other, the urging force for bringing the conveying roller into contact with the separation roller is held by the abutting member against the urging force in a state where the urging force is applied to the holding member by the spring. The member is pushed down. Therefore, since substantially opposite forces are simultaneously applied to both ends of the holding member in the axial direction of the separation roller, depending on the strength of the biasing force of the spring, twisting may occur when the holding member is pushed down by the contact member. Will occur. When the holding member is twisted in this way, the separation roller side biased by the spring of the holding member is not sufficiently lowered, and as a result, the separation roller is separated from the conveying roller by an amount smaller than the target separation amount. There is a fear.

  If the conveyance roller and the separation roller are not sufficiently separated, the sheet may be damaged or torn by pulling out the paper feed tray from the apparatus body while the sheet is in contact with or sandwiched between the conveyance roller and the separation roller. Problems arise.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a sheet separating apparatus capable of separating the separation roller with a target separation amount with respect to the conveying roller, and a sheet feeding apparatus including the sheet separating apparatus. It is to provide a feeding device and an image forming apparatus including the sheet feeding device.

In order to achieve the above object, the invention according to claim 1 is that the conveyance roller contacts the conveyance roller that conveys the sheet and the plurality of sheets that have entered the nip portion formed by contacting the conveyance roller. An apparatus main body configured to hold a separation roller for separating a sheet other than the sheet from a sheet in contact with the conveyance roller, and the separation roller via a rotation shaft so that the separation roller can be brought into contact with and separated from the conveyance roller. A separation roller holding member that can swing relative to the conveying roller, and an urging force that biases the separation roller holding member so that the separation roller holding member swings in a contact direction in which the separation roller contacts the conveying roller A urging release means for releasing the urging force in the abutting direction against the separation roller holding member by the urging means; and a front side from the conveying roller. As the separation roller holding member in the detaching direction to separate the separating roller is swung, possess a separating means for separating the conveying roller and the separation roller by biasing the separation roller holding member, the spacing The means also serves as the urging release means, and switches the urging direction of the urging means with respect to the separation roller holding member so that the urging means urges the separation roller holding member in the abutting direction. as well as release, in which said separation roller holding member in the direction of separation is to oscillate, characterized by Rukoto is energized the separation roller holding member biasing means.

  In the present invention, the separation roller holding member is urged in the separation direction by the separation means in a state where the urging in the contact direction with respect to the separation roller holding member by the urging means is released by the urging release means. The conveying roller and the separation roller can be separated from each other. Thus, when separating the separation roller from the conveying roller, the separation roller holding member is moved in the separation direction in a state where a force in a direction different from the contact direction and the separation direction is not simultaneously applied to the separation roller holding member. It can be swung. Accordingly, the separation roller holding member is prevented from being twisted so that the separation roller is separated from the conveyance roller by a smaller amount than the target separation amount, and the separation roller is separated from the conveyance roller by the target separation amount. Can do.

  As described above, according to the present invention, there is an excellent effect that the separation roller can be separated from the conveying roller by a target separation amount.

The figure which shows the state which the separate roller separated from the feed roller. 1 is a diagram illustrating an example of an image forming apparatus to which a sheet feeding apparatus according to an embodiment is applied. FIG. 3 is a diagram illustrating details of a sheet feeding device. FIG. 3 is a schematic diagram illustrating a configuration of a sheet feeding separation unit. The schematic diagram of the fitting part of a separate roller axis | shaft and a roller holder. The figure explaining the protrusion amount from the roller holder of a separate roller axis | shaft, and the pushing position of the urging | biasing member with respect to a separate roller axis | shaft. The figure which shows the positional relationship of the three axes | shafts of the rotation fulcrum of a roller holder, a separate roller axis | shaft, and a feed roller axis | shaft. The schematic diagram which looked at the state which inserted the paper feed tray with respect to the apparatus main body from the apparatus upper direction. FIG. 4 is a schematic diagram of a sheet feeding separation unit when a sheet feeding tray is inserted into the apparatus main body. The figure which shows the state which the separate roller contact | abutted to the feed roller. FIG. 11 is a cross-sectional perspective view taken along line A-A ′ of FIG. 10. Explanatory drawing about the shape of a biasing member. FIG. 4 is a schematic diagram of a sheet feeding separation unit when a sheet feeding tray is pulled out from the apparatus main body. B-B 'cross-sectional perspective view of FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 2 is a view showing an example of an image forming apparatus to which the sheet feeding apparatus according to the embodiment of the present invention is applied. The image forming apparatus shown in FIG. 2 is a laser printer capable of writing with laser light. 1 (hereinafter simply referred to as a printer).

  In FIG. 2, the printer 1 has an image formation processing unit 90 positioned at the center in the vertical direction, and an original scanning unit 100 is disposed at the upper part and a paper feeding unit 110 is disposed at the lower part with the image formation processing unit 90 as a boundary. Yes.

  The image forming processing unit 90 includes a photosensitive member 2 that forms a cylindrical latent image carrier. Around the periphery of the photosensitive member 2, a charging device 3, a writing device 4, a developing device 5, a transfer device 6 and a cleaning device for performing image forming processing along the rotation direction of the photosensitive member 2 rotating clockwise in the figure. A device 7 is arranged.

  The surface of the photoreceptor 2 is uniformly charged by the charging device 3 during the rotation process, and then an electrostatic latent image corresponding to the image information is formed by the writing device 4, and the electrostatic latent image is visualized by the developing device 5. The toner image is processed. The toner image is transferred by the transfer device 6 to a sheet fed from the paper feeding device 57 provided in the paper feeding unit 110.

  Residual toner is removed from the surface of the photoreceptor 2 after the transfer by the cleaning device 7, and the charge is removed by a charge removal device (not shown), and then the charging device 3 is uniformly charged to prepare for the next image formation.

  A sheet feeding unit 110 that feeds a sheet for transferring a toner image includes a plurality of sheet feeding trays 8 </ b> A that are detachably provided to the apparatus main body, including one disposed in the image forming processing unit 90. , 8B, 8C, 8D. Each of the paper feed trays 8A, 8B, 8C, and 8D is provided with paper feed devices 57A, 57B, 57C, and 57D that can separate sheets in a double feed state.

  Reference numeral 8E in the figure denotes a refeed tray that can be accommodated by inverting the sheet to be image-formed on both sides, and reference numeral 8F denotes a registration roller that sets the registration timing of the sheet. Yes.

  From the sheet feeding devices 57A, 57B, 57C, 57D, the sheet is fed out in the direction indicated by the alternate long and short dash line and reaches the position of the registration roller 8F.

  In the transfer device 6, a transfer conveyance belt 6c is stretched between two stretching rollers 6a and 6b. The transfer / conveying belt 6c is provided so as to be pressed against the surface of the photosensitive member 2 by a stretching roller 6a. Then, a transfer bias is applied to the stretching roller 6 a from a power source (not shown), the toner image is transferred from the photoreceptor 2 to the sheet, and the sheet on which the toner image is transferred is conveyed toward the fixing device 9.

  The fixing device 9 has a configuration in which a heat roller system including a fixing roller 9A and a pressure roller 9B is adopted. The toner carried on the sheet is fixed to the sheet by heating via a heat source built in the fixing roller 9A and pressure applied by the pressure roller.

  The sheet after fixing is discharged toward a post-processing apparatus 10 including a plurality of discharge trays 10A and a stapler 10B that can store sheets sorted in page order or for each image. The post-processing apparatus 10 also includes a paper discharge tray 10C for receiving sheets that are not subjected to post-processing.

  When images are formed on both sides of the sheet, after the toner image is fixed on one side of the sheet, the sheet is not discharged to the post-processing device 10 and is directed toward the reverse conveyance path 8I for double-sided image formation. The sheet is discharged. The reverse conveyance path 8I reaches the position of the registration roller 8F via the refeed tray 8E, and the reversed sheet is fed out again toward the transfer position of the photoreceptor 2.

  The document scanning unit 100 is applied to the scanning optical system 102 for reading the document placed on the document placing table 101 above the image forming processing unit 90, the automatic document feeder B3, and the double-sided image formation. A reversing conveyance member 104 is provided in a lid member 105 that can be opened and closed. The automatic document feeder 103 is also equipped with a document transport belt 107 for introducing documents loaded on the document loading tray 106 onto the document loading table 101.

  Of the paper feeding devices 57A, 57B, 57C, and 57D, the lowermost paper feeding device 57D will be described as a representative. The sheet feeding device 57D includes a pickup roller 11 that feeds out the sheets stacked on the sheet feeding tray 8D, a feed roller 12, a separation roller 13 that is pressed against the feed roller 12, a guide 8G, and a conveying roller 8H. Has been. The other paper feeders 57A, 57B, and 57C have the same configuration.

  The printer 1 has a manual feed tray 81, and a paper feeding device 57E is provided correspondingly. The paper feeding device 57E has the same configuration as the paper feeding device 57D.

FIG. 3 is a diagram showing details of the sheet feeding device 57D.
In FIG. 3, the sheets S that are sheet-like media are aligned by a support member (not shown), and the stacked sheets even if the sheets S are reduced by paper feeding or added by replenishment. The uppermost surface height of S is provided so as to maintain a constant position.

  A symbol X in the drawing indicates a sheet feeding (feeding) direction, and a pickup is provided on the upper surface of the sheet downstream in the sheet feeding direction X at the center in the width direction of the sheet S orthogonal to the sheet feeding direction X. The roller 11 is in contact with its own weight.

  In the vicinity of the downstream side of the pickup roller 11 in the sheet feeding direction X, a feed roller 12 that is a conveyance roller that conveys the sheet S and a separation roller 13 that is a separation roller are arranged in pressure contact with each other. The separation roller 13 separates the sheet S other than the sheet S in contact with the feed roller 12 from the sheet S in contact with the feed roller 12 among the plurality of sheets S entering the nip formed by contacting the feed roller 12. .

  The position of the nip portion between the feed roller 12 and the separation roller 13 is set to a height level equivalent to that of the uppermost sheet S among the stacked sheets S.

  The feed roller 12 is provided on a feed roller shaft 12A supported in a cantilevered manner on a main body frame (not shown), and rotates synchronously with a gear 12G integrally provided on the feed roller shaft 12A.

  The gear 11G meshes with a gear 11G provided integrally with the pickup roller shaft 11A of the pickup roller 11 via the idle gear 14. Accordingly, the pickup roller 11 and the feed roller 12 are rotated in the direction in which the sheet S is sent out in the sheet feeding direction X.

  The separate roller 13 is provided on the free end side of a separate roller shaft 13A supported in a cantilever manner with the main body frame as a fulcrum with respect to the main body frame so as to be able to rotate forward and backward via a torque limiter (not shown). .

  The feed roller 12 and the separate roller 13 have a shorter life than the printer life and may be replaced in the market. Therefore, in order to improve the exchangeability between the feed roller 12 and the separate roller 13, each of the feed roller 12 and the separate roller 13 is inserted into one end of each of the feed roller shaft 12A and the separate roller shaft 13A. It has become.

  As a method of separating the sheets S stacked on the sheet feeding tray 8D into one sheet, the separation roller 13 is urged against the feed roller 12 that conveys the sheet S, and the torque roller 15 rotates the separation roller 13. It is done by controlling.

  The driving load applied to the separation roller 13 changes according to the number of sheets S entering the nip formed by the contact between the feed roller 12 and the separation roller 13. The operation and non-operation of the torque limiter are determined by the change in the driving load.

  The sheet S is guided from the sheet bundle loaded on the sheet feed tray 8D to the nip between the feed roller 12 and the separation roller 13 by the pickup roller 11. When one sheet S enters the nip between the feed roller 12 and the separation roller 13, the torque limiter slips and becomes inoperative, and the separation roller 13 rotates in the direction in which the sheet S is conveyed. On the other hand, when a plurality of sheets S enter the nip between the feed roller 12 and the separation roller 13, the torque limiter operates to brake the rotation of the separation roller 13, so that one sheet in contact with the feed roller 12. Only the sheet S is separated.

FIG. 4 is a schematic diagram showing the configuration of the sheet separating apparatus.
The separate roller 13 and the torque limiter 15 are held by the roller holder 20 via the separate roller shaft 13A.

  As shown in FIG. 5, the shaft end portion 13a on the side opposite to the separating roller 13 side of the separating roller shaft 13A has a D-shaped cross section. A fitting hole 20a corresponding to the D-shaped cross section of the shaft end portion 13a of the separate roller shaft 13A is formed in the side wall 20b of the roller holder 20 on one end side in the axial direction of the separate roller. The shaft end portion 13a of the separate roller shaft 13A is fitted into the fitting hole 20a of the roller holder 20, whereby the rotation of the separate roller shaft 13A is restricted and the separate roller shaft 13A is held by the roller holder 20. The The separate roller shaft 13A may be rotated by being connected by a universal joint or the like.

  Further, if the feed roller 12 and the separation roller 13 are not in contact with each other in parallel, the sheet S that is nipped and conveyed by both rollers will be skewed. Therefore, the separate roller shaft 13A is held by the roller holder 20 so as to be parallel to the feed roller shaft 12A.

  At this time, if the protrusion amount l of the separate roller shaft 13A from the roller holder 20 shown in FIG. 6 increases, the cantilever length of the separate roller shaft 13A becomes longer, so that the deformation amount by which the separate roller shaft 13A is deformed by the pressure contact force. Will become bigger. Therefore, in this embodiment, as shown in FIG. 6, the pop-out amount 1 is made as small as possible, and the cantilever length of the separate roller shaft 13A is made as short as possible. Further, the contact portion 30 </ b> C of the urging member 30 is configured to press the position in the roller holder 20 closest to the separate roller 13 of the separate roller shaft 13 </ b> A. As a result, the amount of deformation by which the separate roller shaft 13A is deformed by the pressure contact force can be reduced.

  As shown in FIG. 4, a rotation fulcrum 20A and a rotation fulcrum 20B are provided on both side surfaces of the roller holder 20 in the axial direction of the separate roller. The roller holder 20 is swingably supported by an apparatus main body frame (not shown) at the rotation fulcrums 20A and 20B so that the separation roller 13 can be brought into and out of contact with the feed roller 12. The roller holder 20 can be swung by biasing from a biasing member 30 described later.

  Here, the positional relationship among the three axes of the rotation fulcrums 20A and 20B of the roller holder, the separate roller shaft 13A, and the feed roller shaft 12A is important. In this embodiment, as shown in FIG. 7, when the feed roller 12 rotates, the roller holder 20 is rotated by the rotational force so that the pressure contact force of the separate roller 13 to the feed roller 12 is increased. The positional relationship between the three axes is set.

  FIG. 8 is a schematic view of the state in which the paper feed tray 8 is inserted into the apparatus main body as viewed from above the apparatus. FIG. 9 is a schematic diagram of the paper feed separation unit when the paper feed tray 8 is inserted into the apparatus main body. FIG. 10 is a diagram illustrating a state in which the separate roller 13 is in contact with the feed roller 12. 11 is a cross-sectional perspective view taken along the line A-A ′ of FIG. 10.

  The urging member 30 for urging at least the separate roller 13 toward the feed roller 12 is supported by an apparatus main body frame (not shown) so as to be rotatable about the rotation fulcrum shaft 30A. Further, the other end of the spring 60 for pulling the urging member 30 is hooked to the hook portion 30B, which is the lower end portion of the urging member 30 in the figure, and is hooked to the apparatus main body frame (not shown). It has been.

FIG. 12 is an explanatory view of the shape of the urging member 30.
The urging member 30 is rotated counterclockwise in the figure by the tension force of the spring 60 to apply pressure to the separate roller shaft 13A. At this time, in order to prevent the pressure from deviating from the target value, in this embodiment, as shown in FIG. 12, the contact portion 30C that comes into contact with the separation roller shaft 13A of the biasing member 30 is formed into a semicircular shape. The dimensional accuracy of the part 30C is set strictly. Further, in order to prevent the energy of the pressure applied to the separate roller shaft 13A from being consumed for bending deformation of the arm portion 30E between the rotation fulcrum shaft 30A of the urging member 30 and the contact portion 30C, a triangle is applied to the arm portion 30E. The rib 30F is provided to suppress bending deformation of the arm portion 30E.

  When the paper feed tray 8 is inserted into the apparatus main body, the end 50B of the operation lever 50 is pushed by the paper feed tray 8, and the operation lever 50 is rotated clockwise in FIG. 9 about the rotation fulcrum shaft 50A. Rotates. An end portion 50C different from the end portion 50B of the operation lever 50 and the link member 40 are pivotally supported by a shaft member 50C. The operation lever 50 rotates in the clockwise direction in FIG. 40 moves to the left in FIG. Thereby, the engagement between the engaging portion 30 </ b> D at the lower portion of the biasing member 30 and the link member 40 is released, and the biasing member 30 is pulled by the tensile force of the spring 60.

  As a result, the urging member 30 rotates about the rotation fulcrum shaft 30A in the direction of arrow A in FIG. 11, and the contact portion 30C which is the upper end of the urging member 30 moves the separation roller shaft 13A upward in the figure. Push up. As a result, the roller holder 20 is urged upward by the urging member via the separate roller shaft 13A and swings about the rotation fulcrums 20A and 20B. As shown in FIG. 10, the separate roller 13 is fed to the feed roller. 12 abuts. That is, the separation roller 13 is urged toward the feed roller 12 via the separation roller shaft 13A and the roller holder 20 by the urging member 30 that receives a tensile force from the spring 60. Abut.

  FIG. 13 is a schematic view when the paper feed tray 8 is pulled out from the apparatus main body. FIG. 1 is a diagram illustrating a state in which the separate roller 13 is separated from the feed roller 12. FIG. 14 is a B-B ′ cross-sectional perspective view of FIG. 1.

  When the paper feed tray 8 is pulled out from the apparatus main body in the paper feed tray pulling direction indicated by the arrow in FIG. 8, the pressing of the end 50B of the operation lever 50 by the paper feed tray 8 is released. Further, a tensile force is applied to the L-shaped hooking portion 40 </ b> A protruding from the upper surface of the link member 40 by a spring 61. Therefore, when the pressing of the operation lever 50 by the paper feed tray 8 is released, the link member 40 moves to the right in FIG. Thereby, the engaging part 30 </ b> D of the urging member 30 and the link member 40 are engaged, and the engaging part 30 </ b> D of the urging member 30 is pulled by the link member 40.

  As a result, the urging member 30 rotates about the rotation fulcrum shaft 30A in the direction of arrow B in FIG. 14, and the urging of the separation roller 13 to the feed roller 12 is released and the pressure is released. At the same time, the lower portion of the contact portion 30C of the urging member 30 pushes down the L-shaped hook portion 20C provided on the roller holder 20. That is, the roller holder 20 not only releases the urging force of the separating roller 13 from the urging member 30 to the feed roller 12, but also positively obtains a pressing force from the urging member 30, 1, the separate roller 13 is separated from the feed roller 12.

  In addition, the biasing member 30 biases the separation roller 13 away from the feed roller 12 in a state where the biasing member 30 releases the bias of the separation roller 13 to the feed roller 12 and is depressurized. It is possible to suppress the twisting of the roller holder 20. Accordingly, it is possible to prevent the separation roller 13 from being separated from the feed roller 12 by an amount smaller than the target separation amount due to the twist, and to reliably separate the separation roller 13 from the feed roller 12. Can be separated.

  Accordingly, the sheet feed tray 8 is pulled out while the sheet is in contact with or sandwiched between the feed roller 12 and the separation roller 13, and the sheet is prevented from being damaged or torn or from being unable to be pulled out. can do.

  Here, the torque of the torque limiter 15 is in a state where a force is applied in a direction to rotate the separate roller 13 in the direction opposite to the conveyance direction, while the feed roller 12 may rotate in the direction opposite to the conveyance direction. Limited from the drive train. For this reason, the state in which the separation roller 13 is fully lifted by biting on the feed roller 12 becomes a stable state, and the separation roller 13 often does not separate unless the separation roller 13 is pushed down.

  On the other hand, even when the separation roller 13 bites against the feed roller 12 and is stabilized by pushing down the separation roller 13 by the pushing-down force from the urging member 30 as in this embodiment, the separation roller 13 is moved from the feed roller 12. Can be separated.

  In addition, in each of pressurization and depressurization by the urging member 30, either the separate roller shaft 13A or the roller holder 20 may be pressed.

What has been described above is merely an example, and the present invention has a specific effect for each of the following modes.
(Aspect A)
Of the plurality of sheets that have entered the nip formed by contacting the conveying roller such as the feed roller 12 that conveys the sheet, sheets other than the sheet that contacts the conveying roller are separated from the sheet that contacts the conveying roller. The separation roller such as the separation roller 13 and the separation roller are held via the rotation shaft such as the separation roller shaft 13A, and swings with respect to the apparatus main body so that the separation roller can be brought into contact with and separated from the conveyance roller. A separation roller holding member such as a possible roller holder 20, and a biasing member 30 that biases the separation roller holding member so that the separation roller holding member swings in a contact direction in which the separation roller contacts the conveying roller. In the sheet separating apparatus including the urging unit, the urging unit releases the urging in the contact direction with respect to the separation roller holding member. The urging release means such as the hook member 40 and the separation roller holding member are urged to separate the conveyance roller and the separation roller so that the separation roller holding member swings in a separation direction in which the separation roller is separated from the conveyance roller. Separating means such as a biasing member 30 and a link member 40. According to this, as described in the above embodiment, the separation roller can be separated from the transport roller by a target separation amount.
(Aspect B)
In (Aspect A), the separating means also serves as an urging release means, and the urging direction of the urging means with respect to the separation roller holding member is switched, and the urging means applies the urging direction to the separation roller holding member in the contact direction. While releasing the force, the separation roller holding member is urged by the urging means so that the separation roller holding member swings in the separating direction. According to this, as described in the above embodiment, the separation roller can be separated from the transport roller by a target separation amount. Further, by pressing down the separation roller by the urging force from the urging means in the separation direction, the separation roller can be separated from the conveyance roller even when the separation roller bites against the conveyance roller and is stabilized.
(Aspect C)
In (Aspect A) or (Aspect B), the separation roller can be rotated with the rotation of the conveying roller, and a torque limiter that switches between rotation and non-rotation of the separation roller when the rotational load applied to the separation roller changes. A separation roller is provided on the rotation shaft, and when one sheet enters the nip portion, the separation roller rotates, and when a plurality of sheets enter the nip portion, the separation roller does not rotate. It becomes. According to this, as described in the above embodiment, only one sheet can be fed.
(Aspect D)
In (Aspect A), (Aspect B), or (Aspect C), each of the conveyance roller and the separation roller is provided at one end of a rotation shaft such as the feed roller shaft 12A and the separate roller shaft 13A. According to this, as described in the above embodiment, the exchangeability of the transport roller and the separation roller can be improved.
(Aspect E)
It is detachable from the apparatus main body and is fed by a sheet stacking means such as a paper feed tray 8 for stacking sheets, a feed roller such as a pickup roller 11 for feeding out the sheets stacked on the sheet stacking means, and a feed roller. In a sheet feeding apparatus including a sheet separating unit that separates and feeds a sheet into only one sheet, the sheet separating unit includes (Aspect A), (Aspect B), (Aspect C), or (Aspect D). A sheet separating apparatus such as was used. According to this, as described in the above embodiment, when the sheet stacking unit pulls out the sheet in contact with or sandwiched between the conveyance roller and the separation roller, the sheet is damaged, or the sheet stacking unit Can be prevented from being pulled out.
(Aspect F)
In (Aspect E), when the sheet stacking unit is mounted on the apparatus main body, the separation roller comes into contact with the conveyance roller, and when the sheet stacking unit is pulled out from the apparatus main body, the separation roller is separated from the conveyance roller. The biasing member biases the separation roller holding member in conjunction with the attachment / detachment operation of the sheet stacking means with respect to the apparatus main body. According to this, the contact / separation operation of the separation roller with respect to the transport roller can be realized without using a driving component such as a motor or a solenoid, and the cost can be reduced.
(Aspect G)
In an image forming apparatus such as a printer 1 including an image forming unit such as an image forming processing unit 90 that forms an image on a sheet, and a sheet feeding unit that feeds a sheet stacked on the sheet stacking unit to the image forming unit. As the sheet feeding means, the sheet feeding device of (Embodiment E) or (Aspect F) was used. According to this, as described in the above embodiment, it is possible to prevent the sheets from being torn and the sheet stacking means from being pulled out, and good image formation can be performed.

DESCRIPTION OF SYMBOLS 1 Printer 2 Photoconductor 3 Charging device 4 Writing device 5 Developing device 6 Transfer device 6a Tension roller 6b Tension roller 6c Transfer conveyance belt 7 Cleaning device 8 Paper feed tray 8A Paper feed tray 8B Paper feed tray 8C Paper feed tray 8D Feed Paper tray 8E Refeed tray 8F Registration roller 8G Guide 8H Transport roller 8I Reverse transport path 9 Fixing device 9A Fixing roller 9B Pressure roller 10 Post-processing device 10A Paper discharge tray 10B Stapler 10C Paper discharge tray 11 Pickup roller 11A Pickup roller shaft 11G gear 12 feed roller 12A feed roller shaft 12G gear 13 separate roller 13A separate roller shaft 13a shaft end 14 idle gear 15 torque limiter 20 roller holder 20A rotation fulcrum 20B rotation fulcrum 20C Hooking portion 20a Fitting hole 20b Side wall 30 Biasing member 30A Rotating fulcrum shaft 30B Hooking portion 30C Contact portion 30D Engaging portion 30E Arm portion 30F Rib 40 Link member 40A Hooking portion 50 Operation lever 50A Rotating fulcrum shaft 50B End portion 50C Shaft member 50C Paper feeding device 60 Spring 61 Spring 81 Manual tray 90 Image forming processing unit 100 Document scanning unit 101 Document placement table 102 Scanning optical system 103 Automatic document feeding device 104 Reverse conveyance member 105 Cover member 106 Document placement tray 107 Document conveyance belt 110 Feeder

Japanese Patent No. 3048212

Claims (6)

A transport roller for transporting the sheet;
A separation roller for separating a sheet other than the sheet in contact with the conveyance roller from the sheet in contact with the conveyance roller, out of the plurality of sheets entering the nip portion formed by contacting with the conveyance roller;
A separation roller holding member that holds the separation roller via a rotating shaft and is swingable with respect to the apparatus main body so that the separation roller can be brought into contact with and separated from the conveying roller;
A sheet separating apparatus comprising: a biasing unit that biases the separation roller holding member so that the separation roller holding member swings in a contact direction in which the separation roller is brought into contact with the conveyance roller;
An urging release means for releasing the urging in the abutting direction with respect to the separation roller holding member by the urging means;
Separation means for biasing the separation roller holding member to separate the conveyance roller and the separation roller so that the separation roller holding member swings in a separation direction for separating the separation roller from the conveyance roller. Yes, and
The separation means also serves as the bias release means, and switches the biasing direction of the biasing means with respect to the separation roller holding member, and biases the biasing means in the contact direction with respect to the separation roller holding member. with releasing the energizing, as the separating roller holding member is swung to the direction of separation, the sheet separating device according to claim Rukoto is energized the separation roller holding member biasing means. In the sheet separating device 請 Motomeko 1,
The separation roller is rotatable with the rotation of the conveying roller,
The separation roller is provided on the rotating shaft via a torque limiter that switches between rotation and non-rotation of the separation roller when a rotational load applied to the separation roller changes.
The sheet separating apparatus according to claim 1, wherein the separation roller rotates when one sheet enters the nip portion, and the separation roller does not rotate when a plurality of sheets enter the nip portion. The sheet separating apparatus according to claim 1 or 2 ,
A sheet separating apparatus, wherein each of the conveying roller and the separating roller is provided at one end of a rotating shaft corresponding to each of the conveying roller and the separating roller. A sheet stacking means that is detachable from the apparatus main body and stacks sheets; and
A feeding roller for feeding out the sheets stacked on the sheet stacking means;
In a sheet feeding apparatus provided with sheet separating means for separating and feeding the sheet fed by the feeding roller into only one sheet,
A sheet feeding apparatus using the sheet separating apparatus according to claim 1, 2 or 3 as the sheet separating means. The sheet feeding apparatus according to claim 4 , wherein
The separation roller comes into contact with the transport roller when the sheet stacking unit is mounted on the apparatus main body, and the separation roller is separated from the transport roller when the sheet stacking unit is pulled out from the apparatus main body. The sheet feeding device, wherein the biasing member biases the separation roller holding member in conjunction with the attachment / detachment operation of the sheet stacking unit with respect to the apparatus main body. Image forming means for forming an image on a sheet;
In an image forming apparatus comprising: a sheet feeding unit that feeds sheets stacked on a sheet stacking unit to the image forming unit;
An image forming apparatus using the sheet feeding device according to claim 4 or 5 as the sheet feeding means.

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