JP2006056641A - Sheet feeder and image forming device having the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet feeder capable of easily treating jamming of sheets. <P>SOLUTION: The sheet feeder 41 comprises a feeder body, a paper feed cassette 2 attachable/detachable to/from the feeder body with sheets stacked therein, a paper feed roller 3 to feed the sheets stacked in the paper feed cassette 2, a sheet separation means 61 which has a separation pad 4 to press the fed sheet against the paper feed roller 3 and separates the sheets one by one when the sheets overlap, and an attachment/detachment means 62 to attach/detach the sheet separation means 61 to/from the paper feed roller 3 as the paper feed cassette 2 is attached/detached to/from the feeder body. The paper feed roller 3 is provided on the feeder body, the sheet separation means 61 is provided on the paper feed cassette 2, and the paper feed cassette 2 is attachable/detachable in the direction across (orthogonal to) the sheet feeding direction. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a sheet supply apparatus that separates and supplies sheets one by one and an image forming apparatus that includes the sheet supply apparatus in an apparatus main body.

  Conventionally, a sheet supply apparatus is incorporated in a sheet handling apparatus that handles sheets, and supplies sheets to a sheet processing unit that processes sheets. Examples of the sheet handling apparatus include an image forming apparatus that forms an image on a sheet, a binding apparatus that binds a sheet bundle, a punching apparatus that opens a hole in a sheet or a sheet bundle, and a folding apparatus that folds the sheet bundle. Examples of the image forming apparatus include a copying machine, a printer, a facsimile, and a complex machine of these.

  For example, a sheet supply device provided in an image forming apparatus supplies a sheet to an image forming unit that forms an image on the sheet. Hereinafter, a sheet supply device provided in the image forming apparatus will be described as an example.

  Some of the sheet supply apparatuses of the first conventional example include a separation member such as a separation pad, a separation roller, and a separation sheet so that the sheets can be fed one by one.

  In this case, there is a feed retard sheet feeding mechanism as a mechanism that includes a separation roller to separate and supply sheets (see Patent Document 1). This feed retard sheet feeding mechanism is often incorporated in a sheet feeding apparatus in which a sheet feeding cassette can be attached and detached in a direction substantially perpendicular to the sheet conveying direction. Further, there is a Duplo paper feed mechanism as a mechanism for separating and supplying sheets using a separation pad (see Patent Document 2).

  A sheet supply apparatus according to a second conventional example will be described with reference to FIGS. FIG. 12 is a schematic cross-sectional view of the sheet supply apparatus. FIG. 13 is a perspective view of the sheet supply apparatus in which the user has pulled out the sheet cassette.

  The sheet supply apparatus 910 is provided in a laser beam printer 900 that is an example of an image forming apparatus. The paper feed roller 903 is supported by a paper feed roller shaft 932. Both ends of the paper feed roller shaft 932 are supported by the paper feed cassette 902. The separation pad 904 is affixed to the pad holder 933 with double-sided tape. The pad holder 933 is assembled to the paper feed cassette 902 so as to be rotatable about a rotation shaft 902 a of the paper feed cassette 902. The pad spring 934 always pushes the pad holder 933 toward the paper feed roller 903 side. When the paper feed cassette 902 is pulled out from the apparatus main body 901 of the laser beam printer 900, the paper feed roller 903, the pad holder 933, the pad spring 934, and the separation pad 904 are pulled out of the apparatus main body 901 while being attached to the paper feed cassette 902. It is supposed to be.

JP 7-179237 A JP-A-8-290847

  However, in the sheet supply apparatus of the first conventional example, the sheet supply apparatus provided with the feed retard sheet feeding mechanism has a problem of high cost.

  Further, in the sheet supply apparatus of the first conventional example, the sheet supply apparatus provided with the Duplo sheet feeding mechanism has a problem that it is difficult to pull out the sheet feeding cassette in a direction orthogonal to the sheet feeding direction.

  Since the sheet feeding apparatus 910 of the second conventional example has the sheet feeding roller 903 and the separation pad 904 assembled in the sheet feeding cassette 902, the following problem may occur.

  That is, when the sheet feeding cassette 902 is pulled out from the apparatus main body 901 and the sheet is replenished and the sheet is taken out, the sheet feeding roller 903 and the separation pad 904 prevent the sheet from being replenished and taken out. If the user cannot correctly set the sheet in the sheet feeding cassette 902, the sheet end may be bent, a jam may occur, and an image may be formed obliquely.

  In addition, since the majority of paper feed cassettes 902 are resin molded products, the following problems may occur. Large molded parts are difficult to achieve molding accuracy and are likely to bend and warp. In particular, in the case of a paper feeding cassette corresponding to A3 size sheets, a paper feeding cassette corresponding to A3 full bleed size sheets, a large capacity paper feeding cassette having about 250 sheets or about 500 sheets, or more, The weight of the stacked sheets becomes very heavy, and the cassette may be distorted. In this way, there is a high possibility that the paper feed cassette will bend and warp due to the degree of completion of the molded product and external factors. These deflections and warpages will upset the alignment of the design nominal value. Therefore, if the paper feed cassette 902 is a resin molded product, it is difficult to accurately position the relative positional relationship between the paper feed roller and the image forming unit of the laser printer, as in the case where replenishment of the sheet is difficult. In addition, the sheet edge is bent, the image is skewed, and the leading edge margin and the left register size error are caused.

  In particular, in recent years, colorization, high image quality, and high-speed image formation have progressed, and a slight deviation greatly affects the image. Nowadays, the user's view of the image has become very strict, and even a slight skew of the image and a gap in the margin can distrust the user.

  Therefore, as a countermeasure against these problems, it can be considered that when the paper feed cassette 902 is pulled out, the paper feed roller 903 and the separation pad 904 remain in the apparatus main body 01. However, if the paper feed roller 903 and the separation pad 904 remain in the apparatus main body 901, the following new problem may occur.

  That is, the jam processing becomes difficult. For example, when a jam occurs at the nip between the paper feed roller 903 and the separation pad 904, when the paper feed cassette 902 is pulled out, the nip between the paper feed roller 903 and the separation pad 904 is not released. 902 will be pulled out. As a result, the jammed sheet cannot be reused, and the remaining broken sheet is difficult to remove from the apparatus main body. Therefore, if a separation pad separation mechanism is provided in the apparatus main body so that the nip can be released, the configuration of the sheet feeding apparatus becomes complicated, and the separation mechanism is provided in a limited space in the apparatus main body. The problem of difficulty arises. In addition, the complicated separation mechanism causes failure and usability deterioration. In addition, this increases the cost of the sheet supply apparatus. Further, if the paper feed roller 903 and the separation pad 904 are left in the apparatus main body 901, the exchangeability of the separation pad 904 is also deteriorated.

  In general, the life of the separation pad 904 is shorter than the life of the apparatus main body 901. In this case, the separation pad 904 must be set as a replacement part and replaced by a user or a service person. If a general user can continue to use the laser beam printer 900 by replacing parts regardless of the lifetime of the apparatus main body 901, the general user will want to replace the parts. The replacement of the paper feed roller 903 attached to the apparatus main body 901 is becoming established in the market as a general one. However, in the case of the separation pad 904, there is almost no configuration left in the apparatus main body 901, and there is no configuration that allows a general user to replace it. This is because if the separation pad 904 is to be replaced, the replacement work is pressed against the user in a very limited space, and no user accepts the work.

  In recent years, multi-function printers including a copying machine as well as a laser beam printer, which are optionally provided with a reading device, a paper feeding device, and a paper discharging device are becoming widespread. It is common for users to print images on sheets, and various images are printed on various media. The durability of the apparatus main body is improved to withstand such a large amount of output. However, consumable parts such as separation pads have a problem with the durability of the rubber itself, and problems such as “slip” and “abnormal noise” occur after the supply of a certain number of sheets is completed. If it is necessary to replace the device main body for some of these parts, the user will not accept the device. Of course, if the interchangeability is not good, it will also be unacceptable to the user.

  The present invention makes it possible to leave the rotating body on the apparatus main body side, and to pull out the pressure contact separating means together with the sheet stacking means from the apparatus main body in a direction intersecting the sheet feeding direction, thereby facilitating sheet jam processing. It is an object of the present invention to provide a sheet feeding device having features such as being able to be performed and easily exchanging the friction member of the pressure contact separating means.

  An object of the present invention is to provide an image forming apparatus capable of improving accurate image formation and image forming efficiency.

  In order to achieve the above object, a sheet feeding apparatus according to the present invention includes an apparatus main body, a sheet stacking unit on which sheets are stacked and detachably attached to the apparatus main body, and provided in the apparatus main body, and is stacked on the sheet stacking unit. A rotating body that feeds out the sheet; and a friction member that is provided in the sheet stacking unit and that can be pressed against the rotating body when the sheet stacking unit is mounted on the apparatus main body. Sheet separating means for separating the friction member and the rotating body one by one, and the sheet stacking means is detachable in a direction intersecting the sheet feeding direction by the rotating body, When the sheet stacking means is attached to or detached from the apparatus main body, contact / separation means for contacting / separating the friction member to / from the rotating body is provided.

  In order to achieve the above object, an image forming apparatus according to the present invention includes an image forming unit that forms an image on a sheet, and the sheet supply device that supplies the sheet to the image forming unit.

  In the sheet feeding apparatus of the present invention, the rotating body is provided in the apparatus main body, the sheet separating means having a friction member is provided in the sheet stacking means, and when the sheet stacking means is pulled out from the apparatus main body, the contact / separation means is the sheet separating Since the means is separated from the rotating body and the friction member is separated from the rotating body, the jam sheet generated between the rotating body and the friction member can be easily removed without breaking.

  The image forming apparatus according to the present invention includes a sheet supply device in which the rotating body is provided in the apparatus main body, and therefore maintains a relative positional relationship between the rotating body and the image forming unit regardless of whether the sheet stacking unit is attached or detached. Thus, an image can be accurately formed at a desired position of the sheet fed from the sheet feeding apparatus. In addition, since the jam processing and the replacement of the friction member can be performed quickly, the image forming efficiency can be increased.

  Hereinafter, a sheet supply apparatus according to an embodiment of the present invention and a laser beam printer as an image forming apparatus including the sheet supply apparatus in an apparatus main body will be described with reference to the drawings. However, the materials, shapes, and relative arrangements of the components described in this embodiment should be changed as appropriate according to the configuration of the apparatus to which the invention is applied and various conditions. The present invention is not intended to be limited to the embodiment.

  The sheet supply apparatus is incorporated in a sheet handling apparatus that handles sheets, and supplies sheets to a sheet processing unit that processes sheets. Examples of the sheet handling apparatus include an image forming apparatus that forms an image on a sheet, a binding apparatus that binds a sheet bundle, a punching apparatus that opens a hole in a sheet or a sheet bundle, and a folding apparatus that folds the sheet bundle. Examples of the image forming apparatus include a copying machine, a printer, a facsimile, and a complex machine of these.

  The sheet supply apparatus of the present embodiment is provided in a laser beam printer as an image forming apparatus, but is provided in any of the above sheet handling apparatuses, and is not provided only in the laser beam printer. .

  Hereinafter, the laser beam printer and the sheet supply apparatus will be described in this order.

(Laser beam printer)
FIG. 11 is a schematic front cross-sectional view of a laser beam printer as an image forming apparatus including the sheet supply apparatus according to the embodiment of the present invention.

  Under the apparatus main body 91 of the laser beam printer 90, two upper and lower sheet feeding cassettes 2 for stacking and storing sheets P are mounted. The paper feed cassette 2 is detachably attached to the apparatus main body 91 of the laser beam printer 90. The paper feed roller 3 feeds the sheets P stacked in the paper feed cassette 2 one by one from the uppermost sheet. When a plurality of sheets P sent out by the paper feed roller 3 are fed in the separation pad 4, the separation pad 4 blocks the sheets other than the uppermost sheet by the frictional separation action in cooperation with the paper feed roller 3. It has become. The transport roller 5 and the driven roller 6 form a transport roller pair, pull out the sheet P sent out by the paper feed roller 3 from the paper feed cassette 2, and transport it to the next process. The guide member 7 guides the sheet P conveyed by the conveying roller pairs 5 and 6 to the registration roller pairs 8 and 9. The registration roller pair 8, 9 is formed by a registration upper roller 8 and a registration lower roller 9. The registration roller pairs 8 and 9 feed the sheet P between the photosensitive drum 11 and the transfer roller 15 at a predetermined timing after the conveyed sheet P is corrected in skew by a registration shutter (not shown).

  A process cartridge 10 as image forming means is detachably mounted on the apparatus main body 91. Inside the process cartridge 10, a photosensitive drum 11, a primary charger 12, a developing device 13, and the like disposed around the photosensitive drum 11 are provided. The laser scanner 14 irradiates the photosensitive drum 11 with laser light according to image information to form a latent image. The latent image is developed by the developing device 13 to become a toner image. The transfer roller 15 is in pressure contact with the photosensitive drum 11 and transfers the toner image on the photosensitive drum 11 to the sheet when the sheet P passes between the transfer roller 15 and the photosensitive drum 11.

  The conveyance guide 16 guides the sheet P after image transfer to the fixing device 17. The fixing device 17 fixes the toner image on the sheet P with the fixing roller 18 and the pressure roller 19. The fixing paper discharge roller 20 and the fixing paper discharge roller 21 send out the sheet from the fixing device 17. The sheet P that has passed through the fixing device 17 is sent to the second paper discharge roller pair 23 by the first paper discharge roller pair 22 and discharged outside the apparatus main body 91 with the image forming surface facing down. The FD paper discharge tray 24 is formed on the upper surface of the apparatus main body 91 so that sheets on which toner images are fixed are stacked.

  Further, the conveyance switching flapper 25 sorts the sheet P that has passed through the fixing device 17 into a conveyance path that leads to the FD paper discharge tray 24 and a conveyance path that sends it straight. The pair of FU paper discharge rollers 26 discharges the sheet P sent straight out by the conveyance switching flapper 25 to the outside of the apparatus main body 91. The FU paper discharge tray 27 receives the sheet P sent out of the apparatus main body 91 by the FU paper discharge roller pair 26 with the image forming surface facing upward.

  The sheet P that has passed through the fixing device 17 is conveyed by a predetermined amount. When the first paper discharge roller pair 22 and the second paper discharge roller pair 23 are reversed, the duplex unit 28 guides the sheet P to the receiving unit 29 of the duplex unit 28. The sheet P sent to the duplex unit 28 is guided again to the registration roller pairs 8 and 9 by the first conveyance roller pair 30 and the second conveyance roller pair 31. Then, the sheet P is fed between the photosensitive drum 11 and the transfer roller 15, the toner image is transferred to the second surface, the toner image on the second surface is fixed by the fixing device 17, and the FD discharge tray 24. Or, it is discharged to the FU discharge tray 27.

(Sheet feeding device)
The sheet supply device 41 will be described with reference to FIGS.

  The sheet supply apparatus 41 includes an apparatus main body 91 serving as an apparatus main body, a sheet feeding cassette 2 serving as a sheet stacking unit on which sheets are stacked and detachable from the apparatus main body 91, and a rotation for feeding out the sheets stacked on the sheet feeding cassette 2. A sheet separating means 61 having a sheet feeding roller 3 as a body and a separating pad 4 as a friction member for separating the sheets one by one when the fed sheets are pressed against the sheet feeding roller 3 and overlapped with each other. And a contact / separation means 62 for bringing the separation pad 4 into and out of contact with the paper feed roller 3 when the paper feed cassette 2 is attached to and detached from the device main body 91, and the paper feed roller 3 is provided in the device main body 91. A sheet separating unit 61 is provided in the sheet feeding cassette 2, and the sheet feeding cassette 2 intersects (perpendicular to) the sheet feeding direction (arrow D direction in FIG. 1) (in the arrow AB direction in FIG. 1). It has become the de-freely.

  The intermediate plate 50 is assembled to the sheet feeding cassette 2 so as to be rotatable about a rotation fulcrum 2b provided in the sheet feeding cassette 2, and the sheets P are stacked thereon. The intermediate plate spring 51 is a compression spring that urges the intermediate plate 50 upward so that the sheets P stacked on the intermediate plate 50 are in contact with the sheet feeding roller 3 with a predetermined contact pressure. In the paper feed cassette 2, when the paper feed cassette 2 is pulled out from the apparatus main body 91 of the laser beam printer 90, the middle plate 50 is temporarily pushed down or locked against the pressing force of the middle plate spring 51. An unillustrated intermediate plate pressing mechanism for keeping the intermediate plate 50 pressed down is provided. With this push-down mechanism, when the paper cassette 2 is pulled out from the apparatus main body 91, the paper cassette 2 can be smoothly pulled out with the sheet P and the paper roller 3 being separated. When the sheet feeding cassette 2 is mounted on the apparatus main body, the lowering of the intermediate plate 50 is released by the depressing mechanism, and the sheet P is brought into contact with the sheet feeding roller 3 with a predetermined contact pressure by the intermediate plate spring 51. It has become.

  The side regulating plates 52 and 53 are members that regulate the position of the sheet P stacked on the middle plate 50 in the lateral direction (arrows A and B in FIG. 1). The front side restricting plate 52 and the back side restricting plate 53 each have a rack, and are connected and interlocked with a common pinion gear meshing with both racks so as to approach and separate from each other. The rack and pinion gear are not shown.

  The front side regulating plate 52 has an operation handle 52a. When the operation handle 52a is picked up by the user, the lock on the sheet cassette 2 is released, and the front side regulating plate 52 can be moved by hand. Further, when the operation handle 52a is released from the user, the operation handle 52a is re-engaged with the sheet cassette 2 to restrict the movement of the front side regulating plate 52. After the user loads the sheet P on the middle plate 50, the user grasps the operation handle 52a and moves the front side regulating plate 52 to the position where the pressing surface 52b of the front side regulating plate 52 contacts the front end of the sheet P. When moving in the direction, the back side restricting plate 53 interlocked with the front side restricting plate 52 moves in the direction of arrow B and approaches the back end of the sheet P, and the rear side restricting plate 53 is pushed. The pressure surface 53a abuts on the back end of the sheet P. As a result, both sides of the sheet are width-aligned again by the restricting plates 52 and 53.

  The rear end regulating plate 54 is a member that regulates the rear end position of the sheet P. The rear end restricting plate 54 has an operation handle 54 a similar to the front side restricting plate 52. When the user grasps the operation handle 54a, the rear end restricting plate 54 is released from being locked with respect to the paper feed cassette 2, and the rear end restricting plate 54 can be moved by hand. When the trailing edge regulating plate 54 that has become movable is moved to the wall surface 2c side of the sheet feeding cassette 2 by hand, the pressing surface 54b of the trailing edge regulating plate 54 pushes the trailing edge of the sheet P, and The front end can be brought into contact with the wall surface 2 c of the paper feed cassette 2. As a result, the position of the sheet can be regulated in the sheet conveyance direction by the pressing surface 54 b of the trailing edge regulating plate 54 and the wall surface 2 c of the sheet feeding cassette 2.

  The paper feed roller 3 is a rubber roller. The feed roller 57 is a resin roller. The paper feed roller 3 has a half-moon shape (D-shape). The diameter of the paper feed roller 3 is set to be slightly larger than the diameter of the paper feed roller 57. The sheet feeding roller 3 as a rotating body and the sheet feeding rollers 57 arranged on both sides thereof are supported by a sheet feeding roller shaft 32 as a rotating shaft.

  Next, the operation of the sheet supply apparatus 41 will be described. The sheet feeding roller 57 waits while being in contact with the sheet P and the separation pad 4, and the sheet feeding roller 3 is waiting with the flat portion 3a facing the sheet P side. At this time, the paper feed roller 3 forms a predetermined gap between the paper feed roller 57 and the sheet P. When a rotational force is transmitted to the sheet feeding roller shaft 32 at a predetermined timing from the signal indicating that the sheet feeding operation is ON, the sheet feeding roller 3 rotates and the arc portion 3b having a diameter larger than the sheet feeding roller 57 is formed on the sheet P. Abut. The sheet feeding roller 3 starts to pull out the sheet P from the sheet feeding cassette 2 by the frictional force of the sheet feeding roller 3 itself and the biasing force of the middle leaf spring 51. The sheet feeding roller 57 is driven to rotate following the movement of the sheet P.

  When the arc portion 3b of the sheet feeding roller 57 is rotated to a position where it contacts the separation pad 4, the sheet feeding roller 3 and the separation pad 4 form a nip. The sheet P pulled out from the paper feed cassette 2 is guided to the nip between the paper feed roller 3 and the separation pad 4. When a plurality of sheets P pulled out from the sheet feeding cassette 2 are overlapped, a sheet other than the uppermost sheet is held by the separation pad 4 by the frictional force between the sheet feeding roller 3 and the separation pad 4, and only the uppermost sheet is It is sent to the conveying roller pairs 5 and 6. When the sheet P is fed to the pair of conveying rollers 5 and 6, the sheet feeding roller 3 again faces the flat portion 3a and stops rotating. The nip between the sheet feeding roller 3 and the separation pad 4 is also opened, and the sheet P is conveyed downstream by the conveying roller pairs 5 and 6.

  Next, the sheet separating means 61 will be described. The sheet separating means 61 includes a pad block 55, a pad holder 33 as a holding member, a separation pad 4 as a friction member, a rotating shaft 55a on the pad block 55, a pad spring 34, and the like. Note that a separation roller or a separation sheet that is formed of a friction material instead of the separation pad 4 and is detachable from the pad holder 33 may be used as the friction member. The friction member is not limited to the separation pad.

  The pad block 55 is a member that holds the pad holder 33. The separation pad 4 is affixed to the pad holder 33 with double-sided tape. The pad holder 33 is rotatably assembled to a rotation shaft 55a on the pad block 55. In addition, the pad holder 33 is pushed toward the sheet feeding roller 57 by the pad spring 34. For this reason, the separation pad 4 is always in contact with the sheet feeding roller 57 with a predetermined contact pressure. When the sheet is supplied, the separation pad 4 sandwiches the sheet with the sheet feeding roller 3 by the pressing force of the pad spring 34 and separates the overlapping sheets from the uppermost sheet.

  Next, the contact / separation means 62 will be described. The contact / separation means 62 includes a pad block spring 56 as an urging means, a positioning cam 60 as an action member, and the like. The pad block 55 is assembled to the paper feed cassette 2 so that the positioning bosses 55d and 55e are inserted into the positioning holes 2d and 2e of the paper feed cassette 2, and the positioning holes 2d and 2e are rotatable about the rotation center. A pad block spring 56 is wound around the positioning boss 55d in a loosely fitted state. The pad block spring 56 is a torsion coil spring. One end of the pad block spring 56 is locked to the paper feed cassette 2, and the other end is hooked on the hook portion 55 b of the pad block 55, and the pad block 55 is urged to rotate in the direction of arrow A in FIG. 2. .

  Next, the cassette rail 58 as the guiding means and the pad block 55 will be described with reference to FIGS. The cassette rail 58 is a member that guides the attachment and detachment of the paper feed cassette 2 with respect to the apparatus main body 91 of the color laser printer 90. The cassette rail 58 is a telescopic rail including a cassette outer rail 58 a fixed to the apparatus main body 91 and a cassette inner rail 58 b pulled out by the paper feed cassette 2. A slit 58e is formed on the side surface of the cassette outer rail 58a. The cassette inner rail 58b is provided with a stopper 58c protruding from the cassette inner rail 58b. The stopper 58c can move between the slit rear end 58f and the slit front end 58g. The cassette inner rail 58b can be pulled out of the apparatus main body and the cassette outer rail 58a by the moving stroke of the stopper 58c.

  The positioning cam 60 is configured to guide and position the pad block 55 against the paper feed roller 3. The positioning cam metal plate 59 supports the positioning cam 60. The positioning cam 60 is press-fitted and held in the positioning cam metal plate 59. The positioning cam metal plate 59 is burred to the burring 58d of the cassette outer rail 58a and integrated with the cassette outer rail. The positioning cam 60 is formed with a pressing pressure portion 60a and a slope portion 60b. The pressing portion 60a presses the back surface 55c of the pad block 55. The inclined surface portion 60b guides the pad block 55 to a predetermined position.

  Next, an operation for causing the separation pad 4 to contact and separate from the paper feed roller 3 in conjunction with the attachment and detachment of the paper feed cassette 2 will be described with reference to FIGS.

  When the user pulls out the paper feed cassette 2 from the apparatus main body 91 in the direction of arrow A in FIG. 5, the pad block 55 assembled to the paper feed cassette 2 is also pulled out of the apparatus main body 91. Since the pad block 55 is pushed in a direction away from the paper feed roller 3 by the block spring 56, the feed block 2 is fed from the pressing pressure portion 60a of the positioning cam 60 along the inclined surface portion 60b as the paper feed cassette 2 is pulled out from the apparatus main body 91. Retreat from the paper roller 3.

  On the other hand, when the paper feed cassette 2 is mounted on the apparatus main body 91, the back surface 55c of the pad block 55 approaches the paper feed roller 3 along the inclined surface portion 60b. When the back surface 55c rides on the pressing portion 60a and the sheet feeding cassette 2 is mounted at a predetermined position, the position of the pad block 55 is determined, and the separation pad 4 is applied to the sheet feeding roller 3 by the predetermined pressing force of the pad spring 34. Press contact.

  Next, procedures for removing the paper feed cassette 2 and replacing the pad block 55 will be described with reference to FIGS. 9 and 10, when the user pulls out the paper cassette 2 from the apparatus main body 91, the paper cassette 2 is connected to the inner rail 58 when a predetermined amount is pulled out, and then pulled out while dragging the cassette inner rail 58b. It is. The sheet feeding cassette 2 stops when the stopper 58c of the cassette inner rail 58b hits the slit front end 58g of the cassette outer rail 58a, and is almost pulled out from the apparatus main body 91.

  In the state in which the paper feed cassette 2 is pulled out, the sheet separating means 61 is pushed by the pad block spring 56 as shown in FIG. Has been evacuated. For this reason, the upper part of the intermediate plate 50 is opened, and stacking of sheets becomes easy. Further, when sheets are stacked on the intermediate plate 50, it is easy to take out the sheets.

  Further, the paper feed cassette 2 can be detached from the apparatus main body 91 when the user releases the connection with the cassette inner rail 58b from the fully pulled out state. In this state, the user can easily stack and take out sheets.

  Further, the separation pad 4 is replaced by removing the paper feed cassette 2 from the apparatus main body 91. The separation pad 4 is exchanged as follows. There are several. First, the separation pad 4 is peeled off from the pad holder 33 and a new separation pad 4 is attached. Second, the entire pad holder 33 is replaced. Third, the pad block 55 is replaced.

  A procedure for replacing the entire pad block 55 will be described. This exchange procedure is a so-called patch type exchange utilizing the elasticity of the parts. The pad block 55 is rotatably assembled to the paper feed cassette 2 by positioning bosses 55d and 55e and positioning holes 2d and 2e. The positioning boss 55e is removed from the positioning hole 2e and can be removed from the paper feed cassette 2 by bending the tongue 55f in which the positioning hole 2e is formed in the direction of arrow C in FIG. As a result, the pad block 55 can be removed from the paper feed cassette 2. In order to incorporate the pad block 55 into the sheet feeding cassette 2, the positioning boss 55 d is inserted into the positioning hole 2 d provided in the sheet feeding cassette 2 through the pad block spring 56 through the positioning boss 55 d. Then, the other positioning boss 55e is inserted into the positioning hole 2e while bending the tongue 55f. Thereafter, when the end portion of the pad block spring 56 is hooked on the hook portion 55b, the assembly is completed.

  In the configuration described above, the sheet feeding device 41 has the sheet feeding roller 3 provided in the apparatus main body 91 and the sheet separating means 61 provided in the sheet feeding cassette 2. At this time, the separation pad 4 of the sheet separating means 61 can be separated from the sheet feeding roller 3, and the jammed sheet generated between the sheet feeding roller 3 and the separation pad 4 can be easily removed without breaking.

  Further, in the sheet supply device 41, when the sheet feeding cassette 2 is pulled out from the apparatus main body 91, the sheet separating means 61 is retracted to a position away from the sheet feeding roller 3 by the contact / separation mechanism 62. Since the upper part is opened, the sheet can be easily replenished and removed, and usability can be improved.

  Since the sheet feeding device 41 can pull out the separation pad 4 from the apparatus main body 91 integrally with the sheet feeding cassette 2, the separation pad 4 can be easily replaced.

  When the sheet feeding apparatus 41 pushes the sheet feeding cassette 2 into the apparatus main body 91, the sheet feeding cassette 2 is pushed by the guide of the cassette rail 58, so the relative position between the sheet feeding roller 3 and the separation pad 4. The relationship can be accurately returned to the original state, and the sheet separation and supply operation can be reliably continued.

  Since the laser beam printer 90 includes the sheet supply device 41 in which the paper feed roller 3 is provided in the apparatus main body, the relative position between the paper feed roller 3 and the process cartridge 10 regardless of whether the paper feed cassette 2 is attached or detached. The relationship can be maintained, and an image can be accurately formed at a desired position of the sheet fed from the sheet feeding device 41. Further, since the sheet processing apparatus 41 can quickly perform jam processing and replacement of the separation pad 4, the image forming efficiency can be increased.

  As described above, according to the present invention, an access for replenishing and taking out a sheet is provided above the sheet feeding cassette, that is, by placing the sheet feeding roller in the sheet feeding unit provided in the apparatus main body. Open up the area to improve usability. In addition, it is possible to guarantee the alignment between the paper feed roller and the image forming unit and improve the printing accuracy. Further, the jam handling property can be improved by making the separation pad contactable / separable from the paper feed roller. By leaving the separation pad in the cassette, the exchangeability of the separation pad can be improved. Furthermore, by providing a guide member provided in the apparatus main body for guiding the attaching / detaching operation of the paper feed cassette, the alignment function of the separation pad with respect to the apparatus main body can be ensured.

1 is an external perspective view of a sheet supply apparatus according to an embodiment of the present invention. 1 is a schematic front sectional view of a sheet feeding device according to an embodiment of the present invention. It is a perspective view of the cassette rail which is a cassette attachment / detachment guide member of the sheet supply apparatus according to the embodiment of the present invention. FIG. 4 is a partial perspective view of a sheet feeding cassette and a cassette rail when the sheet feeding apparatus is mounted in the sheet feeding apparatus according to the embodiment of the present invention. FIG. 4 is a partial perspective view of the sheet feeding cassette and the cassette rail when the sheet feeding cassette is pulled out in the sheet supply apparatus according to the embodiment of the present invention. FIG. 4 is a partial schematic front cross-sectional view of the sheet feeding cassette and the cassette rail when the sheet feeding cassette is pulled out in the sheet supply apparatus according to the embodiment of the present invention. In the sheet supply apparatus according to the embodiment of the present invention, the positioning cam is a plan view of a state where the pad block is pressed against the sheet feeding roller. FIG. 6 is a plan view when the positioning cam is released from pressing the pad block toward the paper feed roller in the sheet supply apparatus according to the embodiment of the present invention. FIG. 4 is a partial perspective view of the sheet feeding cassette and the cassette rail when the sheet feeding cassette is pulled out along the cassette rail in the sheet supply apparatus according to the embodiment of the present invention. In the sheet supply apparatus of embodiment which concerns on this invention, it is a figure for putting block assembly description. 1 is a schematic front sectional view of a laser beam printer as an image forming apparatus provided with a sheet supply apparatus according to an embodiment of the present invention. It is a schematic front sectional view of a conventional sheet supply apparatus. FIG. 10 is a perspective view of a laser beam printer when a sheet feeding cassette is pulled out from the laser beam printer in a conventional sheet supply apparatus.

Explanation of symbols

P sheet 2 paper feed cassette (sheet stacking means)
3 Paper feed roller (rotating body)
4 Separation pad (friction member)
10 Process cartridge (image forming means)
32 Feed roller axis (rotary axis)
33 Pad holder (holding member)
34 pad spring 41 sheet supply device 55 pad block 55a rotating shaft 56 pad block spring (pressing means)
58 Cassette rail (guide means)
58a Cassette outer rail 58b Cassette inner rail 60 Positioning cam (action member)
60a Pressing pressure part 60b Slope part 61 Sheet separating means 62 Contacting / separating means 90 Laser beam printer (image forming apparatus)
91 Main unit

Claims (9)

The device body,
A sheet stacking means in which sheets are stacked and detachable from the apparatus main body;
A rotating body that is provided in the apparatus main body and that feeds out the sheets stacked on the sheet stacking unit;
A friction member that is provided in the sheet stacking unit and is capable of being pressed against the rotating body when the sheet stacking unit is mounted on the apparatus main body; and the fed sheet is disposed between the friction member and the rotating body. Sheet separating means for separating one sheet at a time,
The sheet stacking means is detachable in a direction intersecting a sheet feeding direction by the rotating body;
A sheet feeding apparatus comprising a contacting / separating unit that contacts and separates the friction member with the rotating body when the sheet stacking unit is attached to and detached from the apparatus main body.   When the sheet stacking unit is mounted on the apparatus main body, the contact / separation unit presses the sheet separating unit toward the rotating body to bring the friction member into contact with the rotating body, and the sheet stacking unit is removed from the apparatus main body. The sheet feeding apparatus according to claim 1, wherein the friction member is separated from the rotating body when being pulled out.   The contact / separation means includes an urging means for urging the sheet separating means in a direction for separating the friction member from the rotator, and the friction member against the urging body against the urging force of the urging means. The sheet feeding device according to claim 2, further comprising an action member for contacting the sheet feeding device.   Guiding means for guiding attachment / detachment of the sheet stacking means is provided between the apparatus main body and the sheet stacking means, and the action member is disposed on the guide means, and the friction member is moved to the rotating body by the action member. The sheet feeding device according to claim 3, wherein the sheet feeding device is contacted and separated.   The sheet feeding apparatus according to claim 4, wherein the guide unit includes a plurality of rails combined so as to be movable in the longitudinal direction.   6. The sheet separating unit according to claim 3, wherein the sheet separating unit includes a holding member that holds the friction member and can tilt in a direction in which the friction member is brought into contact with and separated from the rotating body. The sheet feeding apparatus according to claim 1.   The urging means of the contacting / separating means urges the holding member to tilt so that the friction member is separated from the rotating body, and resists the urging force of the urging means by the action member. The sheet feeding apparatus according to claim 6, wherein the holding member is moved so that the friction member is in contact with the rotating body.   The sheet feeding apparatus according to any one of claims 1 to 7, wherein the friction member is replaceable. Image forming means for forming an image on a sheet;
The sheet supply apparatus according to any one of claims 1 to 8, wherein the sheet is supplied to the image forming unit.
An image forming apparatus comprising:

Images