JP2010184804A - Sheet material separating device, paper feeder, and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet material separating device for surely preventing double feed and continuous feed and preventing a sheet material feeding failure such as no feed due to too much friction of separating nips while reducing damage such as friction or scratches to sheet materials due to separating members by setting the friction force of the separating nips to be adequate depending on the type of the sheet materials, and to provide a paper feeder and an image forming device. <P>SOLUTION: The sheet material separating device 70a includes a sheet material stacking plate 71a, a feed roller 72a, a pressing mechanism (73a) for pressing a bunch of sheet materials P' against the feed roller, and the first separating member 74a for elastically contacting the feed roller to form the first separating nip, the first separating nip serving for separating the sheet materials one by one and feeding them. Herein, the second separating member 75a is provided in such a manner as to freely elastically contact or leave the feed roller for elastically contacting the feed roller at the downstream side of the first separating nip to form the second separating nip. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a sheet material separating apparatus for separating sheet materials (a sheet-like member including a recording sheet such as a copy sheet and a resin sheet such as an OHP sheet; the same applies hereinafter) one by one, and the sheet material separating apparatus And a sheet feeding apparatus that feeds a sheet material to the next process such as an image forming unit, and an image forming apparatus that includes the sheet feeding apparatus and forms an image on the sheet material.

  2. Description of the Related Art Conventionally, a sheet material separating device and a paper feeding device in an image forming apparatus such as a copying machine, a facsimile machine, a printer, and a composite machine of these are a sheet material stacking table on which a plurality of sheet materials are stacked, An urging means for urging the bundle upward, a sheet feeding roller that is elastically contactable with the uppermost sheet member of the bundle of sheet members urged upward, and a sheet material conveyance of the sheet feeding roller A separation pad made of a material having a high coefficient of friction such as an elastomer, which is opposed to the downstream side in the direction, and a separation member that is urged by an urging means and elastically contacts the paper feed roller, and is placed on the loading table The sheet feeding roller is rotated from the bundle of sheet materials thus fed to feed the sheet material, and when the sheet material is double fed, the sheet feeding roller and the separating member are elastically contacted with each other by the friction force of the separation pad. Damping the sheet material opposite the paper roller Has become common that friction separation system to prevent double feed to separate and feed one by one.

  For example, in Patent Document 1, a high friction coefficient portion 82 and a low friction coefficient portion 80 (corresponding to the separation pad) are provided on the outer peripheral surface of the separation roller 72 (corresponding to the separation member). A sheet feeding roller 64 (corresponding to the sheet feeding roller) rotated by a motor and a rotatable guide roller 66 having a smaller radius than the sheet feeding roller 64 are provided so as to oppose the sheet material and the height of the sheet material and the separation roller 72. A sheet material supply device is described in which the contact area with the friction coefficient portion 82 is changed according to the sheet material conveyed by the paper feed roller 64. However, the sheet material supply device described in Patent Document 1 is configured so that the contact area between the sheet material and the high friction coefficient portion 82 is configured so that the frictional force of the sheet material is always in a high friction state. Although it is possible to prevent the double feeding of the material, it cannot reduce the separation preventing force of the sheet material, the sheet material is not fed (non-feed: the sheet material is not sent out), and the leading edge of the sheet material There is a problem that it is not possible to reduce the occurrence of rubbing scratches or the like on the part (see FIG. 17 of Patent Document 1).

  Patent Document 2 discloses a sheet stacking means 3 (corresponding to the sheet material stacking table) for stacking sheets (corresponding to the sheet material) and a separation roller 6 (feeding roller) for feeding sheets one by one. And a separation pad 7 (corresponding to the separation member) that is disposed opposite to the separation roller 6 and applies a frictional force to the sheet, a contact that changes the angle of the separation pad 7. There is described a sheet feeding device that provides angle control means and suppresses double feeding of sheets by raising the angle of the separation pad 7 by the contact angle control means when the sheet pushes down the separation pad 7. Yes. However, in the sheet feeding device described in Patent Document 2, even when a thick and strong sheet such as thick paper is fed, the angle of the separating member rises, so that the sheet conveyance load increases and non-feeding occurs. Cannot be prevented (see FIG. 2 in Patent Document 2).

  In Patent Document 3, the manual feed tray 8 (corresponding to the sheet stacking base) and the pressure plate 32 and the paper P (corresponding to the sheet material) as a recording medium are brought into contact with each other, and the paper P is fed by moving on the surface. A sheet feeding roller 31 (corresponding to the sheet feeding roller), a recording medium contacting / separating mechanism for contacting or separating the sheet feeding roller 31 and the uppermost sheet P of the manual feed tray 8 and the pressure plate 32, and the sheet feeding roller 31. And a friction pad 33 (corresponding to the separation pad) as a separation member (corresponding to the separation member) that forms a separation nip by contacting the back surface of the surface of the paper P that contacts the paper feeding roller 31. In the manual feeding device 30 (paper feeding device) for separating and feeding the paper P one by one by the friction pad 33 and the paper feeding roller 31 at the separation nip, according to the thickness of the paper P. Allows manual feed tray 8 angle With, because the angle is optimized between the surface and the recording medium stacking plate 8 of the friction pad 33 (corresponding to the mounting base), paper feeding apparatus for optimally maintaining the separation conditions have been described. However, when a plurality of sheets P enter the separation nip, there is a problem that the gap between the sheet feeding roller 31 and the separation member becomes large, and it is not possible to prevent the sheets P from being double-fed (Patent Document 3). (See FIG. 8 etc.).

  Patent Document 4 discloses a hopper 5 (corresponding to the sheet material stacking table) on which a plurality of papers P (corresponding to the sheet material) are placed, and a paper feeding roller that is rotationally driven by a moving motor and feeds the paper P. 3 (corresponding to the paper feed roller) and a separation pad 35 (corresponding to the separation pad and separation member) arranged to face the paper feed roller 3, and the paper feed roller 3 and the separation pad 35. The paper guide member 11 having the paper guide surface 12 and the paper tip contact surface 13 on both sides of the separation pad 35 is provided. The outer periphery of the paper feed roller 3 is formed of a rubber material 3b, and when the hopper 5 comes into pressure contact with the paper feed roller 3, the paper feed roller 3 is configured to be slightly elastically deformed by the pressure contact force. And the angle at which the paper tip contact surface 13 intersects 14 and the outer peripheral surface (arc surface) of the paper feed roller 3, the gap c at the paper entrance is managed by whether or not the hopper 5 is pressed against the paper feed roller 3. A sheet feeding device that restricts (one sheet) is described. However, if a plurality of sheets enter the gap c at a time due to some accident, the gap between the sheet feeding roller 3 and the separation pad 35 becomes large, and there is a problem that it is not possible to prevent double feeding of sheets. Yes (see FIGS. 1, 3, 5, etc. of Patent Document 4).

  In Patent Document 5, a sheet P (corresponding to the sheet material) stacked on a mounting plate 12 (corresponding to the sheet material stacking table) is sent out by a paper feeding roller 21 (corresponding to the paper feeding roller). In a sheet feeding device that separates and feeds one sheet at a time by a separating inclined surface (corresponding to the separating member), the fixed separating plate 15 having the separating inclined surface has a long and high friction coefficient along the sheet feeding direction. A separation body 34 (corresponding to the separation pad) having a metal leaf spring-like elastic support means 39 is provided so as to be able to protrude and retract with respect to the inclined inclined surface, and the spring against the temperature change and humidity change of the environment. There is described a paper feeding device that exhibits the effect that the coefficient does not fluctuate greatly and the sheet separating action is stabilized. However, although the effect of reducing the blocking force of the separator 34 due to changes in environmental temperature and humidity can be expected, when a plurality of sheets P rush into the separator 34 by the paper feed roller 21, the sheets P are reliably fed double. There is a problem that the sheet P cannot be prevented from being damaged, or that the sheet P is not damaged due to contact between the separator 34 and the sheet P (see FIGS. 3, 4, 11, 12 and the like in Patent Document 5).

  Therefore, in order to solve the problem of the conventional paper feeding device, the present invention is a case where a large number of sheet materials enter the separation nip and a gap is generated between the paper feeding roller and the separation member (separation pad). However, it is possible to reliably prevent double feeding, continuous feeding, etc. with a simple structure, and to prevent troubles in feeding the sheet material such as non-feed due to excessive friction at the separation nip, as well as sheets due to separation members such as rubbing and scratches. An object of the present invention is to provide a sheet material separating device that can reduce the occurrence of damage (damage) to a material, a sheet feeding device including the sheet material separating device, and an image forming apparatus including the sheet feeding device. And

  In order to solve the above-mentioned problem, the invention of the sheet material separating apparatus according to claim 1 is a sheet material stacking table for stacking a plurality of sheet materials, and a sheet material by rotating in contact with the sheet material. A sheet feeding roller that feeds the sheet material, a pressure contact mechanism that presses the bundle of sheet materials stacked on the sheet material stacking table and the sheet feeding roller, and a first separation nip is formed by elastic contact with the sheet feeding roller And a first separating member that separates and feeds the sheet materials one by one in the first separating nip, on the downstream side of the first separating nip of the sheet feeding roller A second separation member that forms a second separation nip by being elastically contacted with the sheet feed roller is provided so as to be elastically contacted or separated from the paper feed roller.

  The sheet material separating apparatus according to claim 2 is the sheet material separating apparatus according to claim 1, wherein the second separating member is divided into a plurality of separating members along the axial direction of the sheet feeding roller. Each separating member is individually elastically contacted or separated from the sheet feeding roller.

  The sheet material separating apparatus according to claim 3 is the sheet material separating apparatus according to claim 2, wherein each separating member of the second separating member is in elastic contact with the sheet feeding roller at the second separating nip. It has a friction member, and each friction member has a different friction coefficient, It is characterized by the above-mentioned.

  The invention of the sheet material separation device according to claim 4 is the sheet material separation device according to any one of claims 1 to 3, wherein one end of the second separation member is pivotally supported by the first separation member, It is characterized in that it can be elastically contacted or separated from the paper feed roller by swinging the other end.

  The sheet material separating apparatus according to claim 5 is the sheet material separating apparatus according to any one of claims 2 to 4, wherein at least one of the second separating members is urged by the urging means. It is characterized in that it is a conveyance roller that is in pressure contact with the sheet feeding roller and can be rotated.

  According to a sixth aspect of the present invention, there is provided the sheet feeding device according to any one of the first to fifth aspects.

  According to a seventh aspect of the present invention, the image forming apparatus includes the paper feeding device according to the sixth aspect.

  The present invention is as described above. According to the invention of claim 1, the sheet material is supplied by rotating the sheet material stacking table on which a plurality of sheet materials are stacked and in contact with the sheet material. A sheet feeding roller to be fed, a pressure contact mechanism that presses the sheet material stack loaded on the sheet material stacking table and the sheet feeding roller, and a first separation nip that is elastically contacted with the sheet feeding roller. A separation member that separates and feeds the sheet materials one by one in the first separation nip, and is arranged on the downstream side of the first separation nip of the sheet feeding roller. The second separation member that forms the second separation nip in contact with the sheet feeding roller is provided so as to be elastically contacted or separated from the sheet feeding roller. The second separation member and the sheet feeding roller are brought into elastic contact with each other to form a second separation nip. And increasing the blocking force against double feeding and continuous feeding to the sheet material, and conversely, by separating the second separation member from the sheet feeding roller and releasing the second separation nip, rubbing, scratching, etc. It is possible to reduce damage to the sheet material due to the separation member, and it is possible to reduce the occurrence of sheet conveyance failure due to excessive friction in the separation nip.

  According to a second aspect of the present invention, in the sheet material separating apparatus according to the first aspect, the second separation member is divided into a plurality of separation members along the axial direction of the sheet feeding roller, and each separation member Are individually elastically contacted with or separated from the sheet feeding roller, so that the friction force of the second separation nip formed by the plurality of second separation members and the sheet feeding rollers is the second separation member. Depending on whether or not the plurality of separating members are brought into elastic contact with the sheet feeding roller, the separation member can be changed stepwise according to the type of the sheet material to be used. In other words, when it is desired to increase the effect of preventing double feeding or continuous feeding, such as when using thin paper, the second separation member is all elastically brought into contact with the sheet feeding roller by the second separation member. When you want to increase the frictional force of the separation nip and increase the double feed prevention force to the sheet material, and conversely when you want to increase the effect of preventing non-feeding when using strong sheet material such as thick paper and hard paper Separating all of the plurality of separation members of the second separation member from the sheet feeding roller, thereby reducing the friction force of the second separation nip and reducing the sheet material feeding load. The optimum frictional force can be selected by changing the number of separation members (divided by the second separation member) that are brought into elastic contact with the sheet feeding roller according to the type of sheet material that uses the frictional force of the nip. Therefore, in addition to the above effects, it is possible to reliably prevent double feeding, continuous feeding, etc., and to prevent troubles in sheet material feeding such as non-feeding, as well as damage to the sheet material due to separation members such as rubbing and scratches. Can be reduced.

  According to a third aspect of the present invention, in the sheet material separating apparatus according to the second aspect, each separation member of the second separation member has a friction member that elastically contacts the sheet feeding roller at the second separation nip. Since each friction member has a different friction coefficient, the friction force of the second separation nip can be changed more finely stepwise by combining a plurality of friction members having different friction coefficients. Therefore, in addition to the above effect, the frictional force of the second separation nip can be adjusted to a more optimal one according to the type of sheet material used.

  According to a fourth aspect of the present invention, in the sheet material separating apparatus according to any one of the first to third aspects, one end of the second separating member is pivotally supported by the first separating member and the other end swings. Thus, the second separation member is assembled to the first separation member, so that the first and second members are assembled when the sheet material separation device is assembled. The workability at the time of assembling the separation members is improved, and it is possible to save the trouble of removing each separation member when any of the separation members is worn, thereby improving the workability at the time of replacing the unit.

  According to a fifth aspect of the present invention, in the sheet material separating apparatus according to any one of the second to fourth aspects, at least one of the second separating members is urged by the urging means and is pressed against the paper feed roller. However, because it is a rotatable transport roller, when a large transport force is required, such as using a strong sheet material such as thick paper or hard paper, a nip is formed by the feed roller and transport roller, The frictional force at the nip can be reduced or eliminated, and the conveyance force transmitted from the sheet feeding roller can be smoothly changed to a predetermined conveyance direction without loss. Accordingly, it is possible to prevent problems in feeding the sheet material such as non-feeding, and to further reduce the occurrence of damage to the sheet material due to separation members such as rubbing and scratches.

  According to the invention of claim 6, since the sheet material separating device according to any one of claims 1 to 5 is provided, the effect can be exhibited in the sheet feeding device.

  According to the seventh aspect of the present invention, since the paper feeding device according to the sixth aspect is provided, the effect can be exhibited in the image forming apparatus.

1 is a configuration explanatory diagram illustrating a schematic configuration of an image forming apparatus according to an embodiment as viewed from the front. FIG. 3 is a perspective view illustrating a sheet feeding tray of the sheet feeding device according to the first embodiment. 1 is a vertical cross-sectional view illustrating a schematic configuration of a sheet feeding device according to Embodiment 1. FIG. FIG. 3 is an enlarged cross-sectional view illustrating the sheet material separation device according to the first embodiment in a state at the start of paper feeding. It is an expanded sectional view showing the sheet material separation device concerning Example 1 in the state at the time of sheet material separation. It is an expanded sectional view showing the separation member concerning Example 1 in the 2nd separation nip elastic contact state. It is an expanded sectional view showing the separation member concerning Example 1 in the 2nd separation nip separation state. It is a perspective view which shows the 2nd separation member of the sheet | seat material separation apparatus which concerns on Example 2. FIG. It is a perspective view which shows the 2nd separation member of the sheet | seat material separation apparatus which concerns on Example 3. FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment of Image Forming Apparatus)
First, the overall configuration of the image forming apparatus according to the present invention will be described. FIG. 1 is an explanatory diagram showing a schematic configuration of a color copying machine exemplified as an embodiment of an image forming apparatus according to the present invention as seen from the front (when viewed from the front door side as the front). The color copying machine 1 shown in the figure is an apparatus main body 1 a, an image reading unit 2 that is disposed at the top of the apparatus main body 1 a and reads a document image (image reading apparatus), and directly below the image reading unit 2. An optical unit 3 that is an exposure apparatus that is disposed and writes an electrostatic latent image on a photosensitive drum described later, an image forming unit 4 that is disposed immediately below the optical unit 3 and forms an image, and the image forming unit 4 The transfer unit 5 is a transfer device that is disposed immediately below the transfer unit 5 and transfers the toner image formed by the image forming unit to the sheet material, and one side of the apparatus main body 1a on the downstream side of the transfer unit 5 in the sheet material conveyance direction. A fixing unit 6 that is a fixing device that fixes the toner image to the sheet material, a sheet feeding unit 7 that is disposed at the bottom of the apparatus main body 1a and feeds the sheet material, and an apparatus main body. Arranged on one side of 1a, A manual feed unit 8 which is a manual paper feed device for feeding the sheet material of the feed, and a sheet material which is disposed outside one side surface of the apparatus main body 1a opposite to the manual feed unit 8 and on which an image is fixed is stacked and mounted. The paper discharge unit 9 is mainly configured.

  The image reading unit 2 is provided with a transparent contact glass 20 on which a document is placed, an optical reading device 21 that reads the document through the contact glass 20, and a contact glass 20 that can be opened and closed. It is mainly composed of an automatic document feeder 22 (ADF: auto document feeder) that automatically conveys, and this optical reader 21 has a light source such as a moving exposure lamp and a moving optical system such as a mirror that moves together with this light source. The image reading apparatus reads an image by irradiating light on a document from a light source and forming an image of reflected light on an image reading element such as a CCD via a mirror and an imaging lens. Then, the image reading unit 2 automatically reads and reads the image of the document set on the contact glass 20 by the user or sent from the automatic document feeder 22 onto the contact glass 20 by the optical reading device 21. The image information is converted into an electric signal and transmitted to a writing control means (not shown).

  Although not specifically shown, the optical unit 3 includes a light source such as an LD (laser diode), a polygon mirror that is a rotating polygon mirror for scanning, a polygon motor that scans the polygon mirror, a scanning optical system such as an fθ lens and a mirror, and the like. An exposure apparatus (writing apparatus) that selectively exposes a surface of a later-described photosensitive drum by irradiating a laser beam from a light source to write an electrostatic latent image.

  The image forming unit 4 includes four image forming units 40Y, 40M, 40C, and 40K corresponding to the three primary colors of the color material and black, yellow, magenta, cyan, and black, and these four image forming units 40 (40Y, 40M). , 40C, 40K) have substantially the same configuration except that the color of the toner is different (hereinafter, subscripts Y, M, C, K indicating which image forming unit is omitted) The image forming unit will be described by way of example.) As shown in the drawing, along the upper surface of the intermediate transfer belt 50 to be described later, the outer peripheral surface of the intermediate transfer belt 50 is moved from the upstream side in the moving direction. They are arranged in the order of yellow, magenta, cyan, and black. Of course, the order of arrangement of the four image forming units is not limited to this order, and can be appropriately changed in consideration of the problem of toner color mixing depending on the application, the shape and type of toner used, and the like. Each image forming unit 40 includes photosensitive drums Y, M, C, and K which are drum-shaped latent image carriers, and the photosensitive drums Y, M, C, and K are centered along the outer periphery thereof. A charging unit 41 (41Y, 41M, 41C, 41K), a developing unit 42 (42Y, 42M, 42C, 42K), and a cleaning unit 43 (43Y, 43M, 43C, 43K) are provided, and each color is a single color. An image forming apparatus that forms a toner image.

  The transfer unit 5 includes an intermediate transfer belt 50 that is an endless belt made of an elastic resin as an intermediate transfer member, and a plurality of tension rollers that stretch the intermediate transfer belt 50 and that are rotationally driven as one of the driving rollers. 51, 52, 53, a tension roller 54 for applying an appropriate tension to the intermediate transfer belt 50, an inner side of the intermediate transfer belt 50, and positions facing the four photosensitive drums Y, M, C, and K, respectively. The four primary transfer rollers 55Y, 55M, 55C, and 55K that can be applied with the primary transfer bias and the intermediate transfer belt 50 are pressed against the outer peripheral surface of the stretching roller 52, and the secondary transfer bias can be applied. The secondary transfer unit 56 and a cleaning unit 57 for cleaning the transfer residual toner on the intermediate transfer belt 50 are mainly configured. A transfer unit 56, at the secondary transfer nip for pressing the tension roller 52 as a backup roller, a transfer device for transferring the superimposed color toner image formed on the intermediate transfer belt 50 to the sheet material. The secondary transfer unit 56 includes a conveyance belt 56a that is stretched around a driving roller and a driven roller, and also serves as a sheet material conveying unit.

  The fixing unit 6 includes a fixing roller 60 provided with a heat generating means such as a halogen heater inside, and a pressure roller 61 that is urged against and pressed by the urging means to form a fixing nip. The fixing device is configured to fix the unfixed toner image on the sheet material by applying heat and pressure to the sheet material carrying the unfixed toner image at the fixing nip. The fixing unit 6 is partitioned from other parts in the apparatus main body 1a by a housing or the like made of a heat-insulating material such as resin, so as to reduce adverse effects of heat transmitted to other parts. It is configured.

  As will be described in detail later, the sheet feeding unit 7 includes four-stage sheet feeding trays 7a, 7b, 7c, and 7d that can accommodate a plurality of sheet materials P (sheet material bundles) each having a predetermined size. Sheet material separating devices 70a, 70b, 70c, and 70d provided in the respective paper feed trays, and these paper feed trays and sheet material separating devices are connected by a conveyance path 10 leading to the secondary transfer nip, In this sheet feeding device, the sheet materials stored in each sheet feeding tray are separated one by one by each sheet material separating device and fed to the secondary transfer nip through the conveyance path 10. Further, in the conveyance path 10, a plurality of conveyance roller pairs 11 provided at predetermined intervals and the relationship between the position of the image on the intermediate transfer belt 50 and the leading edge position of the sheet material are in a predetermined positional relationship. A registration roller pair 12 and the like are also provided for transporting with adjusted timing.

  The manual feed unit 8 includes a manual feed tray 8a which is a mounting table for a user to manually feed an arbitrary sheet material, and a sheet material separation device 80a. This is a manual sheet feeding device that feeds the secondary transfer nip through the conveyance path 10.

  The paper discharge unit 9 stacks the sheet material discharged from the sheet discharge roller pair 90 and the sheet discharge roller pair 90 that discharges the sheet material on which the image has been fixed through the fixing unit 6 from the apparatus main body 1a. This is a part mainly composed of a paper discharge tray 91 that is placed and accommodated, and a sheet material after image formation / fixing is placed and stocked.

(Image forming process and operation of image forming apparatus)
Next, the image forming process of the color copying machine 1 will be described with reference to FIG.
First, in each image forming unit 40, each charging means 41 uniformly charges the outer peripheral surface of each photosensitive drum (Y, M, C, K) and initializes it. Then, based on the image information read by the image reading unit 2 and the image information separated into each color from other devices such as a personal computer to the control means (not shown), the optical drums are uniformly formed by the optical units 3. An electrostatic latent image is formed by selectively exposing the charged outer peripheral surface to lower the charged potential. Next, a developing bias is applied to the electrostatic latent image by the developing means 42 to transfer the toner of each color to visualize and develop the single color toner image of each color. The single-color toner image is applied with a primary transfer bias by each primary transfer roller 55 and transferred onto the intermediate transfer belt 50 in the order of yellow, magenta, cyan, and black, and is superimposed on the intermediate transfer belt 50. As a result, a full-color toner image is obtained.

  On the other hand, in the sheet feeding section 7, each sheet material separating device (70a, 70b,...) Is fed from any one of the sheet feeding trays 7a, 7b, 7c, 7d selected by the control means of the apparatus main body (not shown) or the manual feed tray 8a. 70c, 70d, and 80a), the sheet materials are separated one by one and sent out. The sheet materials fed one by one are transported by the transport roller pair 11, reach the registration roller pair 12 through the transport path 10, and temporarily stop. When the relationship between the position on the intermediate transfer belt 50 on which the full-color toner image is carried and the leading edge position of the sheet material becomes a predetermined positional relationship, the registration roller pair 12 is driven to rotate into the secondary transfer nip. A sheet material is fed to the front.

  In the secondary transfer nip, a secondary transfer bias is applied by the secondary transfer unit 56, and a full-color toner image is transferred from the outer peripheral surface of the intermediate transfer belt 50 to one surface of the sheet material by electrostatic force. The sheet material on which the full-color toner image is transferred is conveyed to the fixing unit 6 by the conveyance belt of the secondary transfer unit 56. Next, in the fixing unit 6, heat and pressure are applied to the sheet material carrying the unfixed full-color toner image in the fixing nip, and the molten toner is fixed to the sheet material by osmotic pressure bonding. The sheet material on which the image is fixed is discharged and stacked on a discharge tray 91 by a pair of discharge rollers 90. Further, the transfer residual toner remaining on and adhering to the intermediate transfer belt 50 after the secondary transfer is cleaned by the cleaning unit 57 and is prepared for the next image formation.

(Feeding device and sheet material separating device)
Next, the sheet feeding device and the sheet material separating device according to the first embodiment of the present invention will be described in detail with reference to FIGS. 2 is a perspective view illustrating a sheet feeding tray of the sheet feeding device according to the first embodiment, FIG. 3 is a vertical cross-sectional view illustrating a schematic configuration of the sheet feeding device according to the first embodiment, and FIG. FIG. 5 is an enlarged cross-sectional view showing the sheet material separating apparatus in the state at the start of feeding, FIG. 5 is an enlarged cross-sectional view showing the sheet material separating apparatus in the first embodiment in the state at the time of separating the sheet material, and FIG. FIG. 7 is an enlarged sectional view showing the separation member according to 1 in a second separation nip elastic contact state, and FIG. 7 is an enlarged sectional view showing the separation member according to Example 1 in a second separation nip separation state.

  As shown in FIG. 1, the sheet feeding device according to the first embodiment includes sheet feeding trays 7a, 7b, 7c, 7d, a manual feed tray 8a, and a sheet material separating device 70a provided for each of these sheet feeding trays. , 70b, 70c, 70d and 80a. The sheet feeding tray 7a accommodates a plurality of sheet materials of a predetermined size, and is a front-rear direction (horizontal direction and a direction perpendicular to the paper surface of FIG. 1) with respect to the apparatus main body 1a (see FIG. 1). In this embodiment, as shown in FIG. 2, a sheet material loading table 71a described later and a first separation member 74a described later are provided together. It has been.

  Here, since each sheet material separation device (70a, 70b, 70c, 70d, and 80a) has substantially the same configuration, the uppermost sheet feed tray 7a will be described as an example, and the others will be described. Omitted. As shown in FIG. 3, the sheet material separating apparatus 70a according to the first embodiment of the present invention includes a sheet material stacking table 71a that stacks a bundle P 'of a plurality of sheet materials and is movable in the vertical direction, and a drive unit. A sheet feeding roller 72a capable of transmitting a driving force, a biasing means 73a for biasing the sheet material stacking base 71a upward to press the sheet material bundle P 'to the sheet feeding roller 72a, and an elastic force to the sheet feeding roller 72a. The first separation member 74a and the second separation member 75a that are in contact with each other to form two separation nips are mainly configured, and the frictional force between the sheet material P and the sheet feeding roller 72a, and the friction between the sheet materials P. Friction that separates and feeds the fed and continuously fed sheet materials one by one according to the balance between the force and the friction force between the first separating member 74a and the second separating member 75a and the sheet material P This is a separation type sheet material separation device.

  The sheet material loading table 71a according to the present embodiment constitutes a bottom plate of the paper feed tray 7a, and is configured such that the side on which the paper feed roller 72a is provided is partially swung to move in the vertical direction. However, the sheet material loading table 71a may be one in which the entire bottom plate moves up and down, and the urging means 73a according to the present embodiment presses the sheet material loading table 71a upward. A device that pulls the table 71a toward the paper feed roller 72a or an urging means that presses the paper feed roller 72a downward may be used. That is, it suffices if a pressure contact mechanism that presses the sheet material stacking base 71a and the paper supply roller 72a relatively is provided. However, since the paper feed roller 72a is connected to a drive gear, a drive means, and the like, it is preferable that the paper feed roller 72a be fixed because the mechanism can be simplified.

  As shown in FIGS. 4 and 5, the separation member according to the present embodiment includes a first separation member 74 a that elastically contacts the paper feed roller 72 a to form a first separation nip, and the first separation nip. The second separation member 75a is formed of a second separation member 75a that elastically contacts the downstream side in the rotation direction (arrow direction in the drawing) of the sheet feeding roller 72a and forms a second separation nip. . The first separating member 74a is attached to the paper feed roller 72a so as to protrude and retract from the paper feed tray 7a, and is constantly urged to the paper feed roller 72a by a coil spring 76a as a biasing means. It is designed to come into elastic contact with the paper roller 72a. The first separation member 74a has a separation pad 77a in a first separation nip portion that is in pressure contact with and in close contact with the sheet feeding roller 72a, and on the sheet material loading table 71a side, as the distance from the sheet material loading table 71 increases. A guide surface A that is inclined in a direction approaching the paper feed roller 72a is provided.

  The separation pad 77a is a friction member made of a material having a high friction resistance such as an elastomer set so that the friction force between the separation pad 77a and the sheet material P is at least higher than the friction force between the sheet materials. Has a function of preventing the sheet material not in contact with the sheet feeding roller 72a from being fed due to the friction force. Further, the guide surface A has a function of guiding the leading edge of the sheet material in the direction in which the guide surface A comes into close contact with the sheet feeding roller 72a.

  In the second separating member 75a according to the present embodiment, one end of the sheet feeding roller 72a along the axial direction is pivotally supported by the first separating member 74a so that the angle is variable, and the other end on the opposite side is free. This free end is configured to abut or separate from the paper feed roller 72a by swinging about an axis provided on the first separation member 74a. The second separation member 75a is also a friction member made of a material having a high friction resistance such as an elastomer in the second separation nip portion that is pressed and in close contact with the sheet feeding roller 72a, like the first separation member 74a. It has a certain separation pad 78a, and the free end side is urged toward the sheet feeding roller 72a side by a coil spring 79a as urging means.

  Further, as shown in FIGS. 6 and 7, a protrusion claw T1a is provided at the free end of the second separating member 75a, and a fixing claw T2a that engages with this is provided on the paper feed tray 7a. When the projection claws T1a and the fixed claws T2a are disengaged, the second separating member 75a is urged by the urging force of the urging means 79a as shown in FIG. The roller 72a is elastically contacted, that is, the second separation nip is formed, and the projection claw T1a is engaged with the fixed claw T2a, so that the separation pad 78a and the paper feed roller 72a are engaged as shown in FIG. Are separated from each other, that is, the second separation nip is released.

  According to the sheet material separating apparatus according to the first embodiment, as described above, the second separating member 75a can be elastically contacted or separated from the sheet feeding roller 72a with a simple configuration, so that a thick sheet or a strong sheet can be obtained. When it is desired to increase the effect of preventing double feeding or continuous feeding, such as when using a material, the second separation member 75a and the sheet feeding roller 72a are elastically contacted to form a second separation nip. In this case, the second separating member 75a is separated from the sheet feeding roller 72a, for example, when a sheet material made of thin paper or a delicate material is used. By releasing the second separation nip, damage to the sheet material due to the second separation member 75a, such as rubbing and scratches, is reduced, and occurrence of poor conveyance of the sheet material due to excessive friction in the separation nip is reduced. Can be easily made It has become way. That is, the choice of whether to increase the frictional force of the separation nip by forming the second separation nip increases, and it becomes easy to match the type of sheet material and the use application of the copying machine 1 that is an image forming apparatus.

(Sheet material separation apparatus according to Example 2)
Next, a sheet material separation apparatus according to Embodiment 2 of the present invention will be described with reference to FIG. However, the sheet material separating devices 70a, (70b, 70c, 70d, and 80a) according to the first embodiment (see FIG. 1) and the sheet material separating devices 70a ′ (70b ′, 70c ′, 70d ′) according to the second embodiment and The only difference from 80a ′) is that the second separating member 75a according to the first embodiment is divided into a plurality of separating members along the axial direction of the paper feed roller 72a in the second embodiment. Here, the second separation member 75a ′ according to the second embodiment will be mainly described, and the other description will be omitted. FIG. 8 is a perspective view illustrating a second separating member of the sheet material separating apparatus according to the second embodiment.

As shown in FIG. 8, the second separating member 75a ′ according to the second embodiment is divided into _three separating members 75a ₁ ′, 75a ₂ ′, and 75a ₃ ′ along the axial direction of the sheet feeding roller 72a. These separation members 75a ₁ ′, 75a ₂ ′, and 75a ₃ ′ are pivotally supported by the first separation member 74a so as to be swingable independently and variable in angle, and each has a free end. It is urged toward the paper feed roller 72a by three coil springs (not shown) as urging means. Of course, the second separating member 75a ′ is not limited to the one separated into three parts, and is divided into a plurality of parts along the axial direction of the sheet feeding roller 72a. 72a may be elastically contacted or separated.

Similarly to the first embodiment, the second separation member 75a ′ is a second separation nip that is in pressure contact with and closely contacts the sheet feeding roller 72a for each of the separation members 75a ₁ ′, 75a ₂ ′, and 75a ₃ ′. Separation pads 78a ₁ ′, 78a ₂ ′, 78a ₃ ′ made of a material having a high friction resistance such as an elastomer are provided in the portion, and these separation pads 78a ₁ ′, 78a ₂ ′, 78a ₃ ′ are respectively frictional. The coefficients are different.

In addition, similar to the first embodiment, projection claws T1a ₁ ′, T1a ₂ ′, T1a ₃ ′ are provided at the free ends of these separating members 75a ₁ ′, 75a ₂ ′, 75a ₃ ′, respectively. The paper tray 7a is provided with three fixing claws (not shown) that engage with the paper tray 7a, and these projection claws T1a ₁ ′, T1a ₂ ′, T1a ₃ ′ and the paper feed tray side are provided. Three fixed claws can be engaged and released.

As described above, according to the sheet material separating apparatus according to the second embodiment, the separation member 75a ₁ ′, 75a ₂ ′, 75a ₃ ′ is divided along the axial direction of the sheet feeding roller 72a, and these Since the second separation member 75a ′ can be elastically contacted or separated from the paper feed roller 72a, the separation pads 78a ₁ ′, 78a ₂ ′, and 78a ₃ ′, which are friction members, have different friction coefficients. The frictional force of the second separation nip formed by the plurality of second separation members and the sheet feeding roller determines which of the plurality of separation members of the second separation member is brought into contact with the sheet feeding roller. By combining each of the above, it is possible to change in a stepwise manner according to the type of sheet material to be used. That is, the frictional force of the second separation nip can be adjusted to an optimum value according to the type of sheet material used.

(Sheet material separating apparatus according to Example 3)
Next, a sheet material separating apparatus according to Embodiment 3 of the present invention will be described with reference to FIG. However, the sheet material separation devices 70a ′ (70b ′, 70c ′, 70d ′ and 80a ′) according to the second embodiment and the sheet material separation devices 70a ″ (70b ″, 70c ″, 70d ″ and 80a ”according to the third embodiment. ") and the difference is' three separate members 75a ₁ 'of the second separation member 75a according to example 2, 75a _2', 75a ₃ 'of the separation member 75a ₁ at each end', 75a ₃ However, in the third embodiment, only the conveyance rollers 75a ₁ ″ and 75a ₃ ″ are provided. Therefore, here, the conveyance rollers 75a ₁ ″ and 75a of the second separation member 75a ″ according to the third embodiment are mainly used here. ₃ ”will be described, and other descriptions will be omitted. FIG. 9 is a perspective view illustrating a second separation member of the sheet material separation apparatus according to the third embodiment.

As shown in FIG. 9, the conveyance rollers 75a ₁ ″ and 75a ₃ ″ of the second separation member 75a ″ according to the third embodiment are supported by the first separation member 74a so as to be swingable and pivotally supported at variable angles. A drum roller is rotatably supported on a member, and is urged toward the sheet feeding roller 72a by a coil spring (not shown) as an urging unit. The second separating member 75a ″ according to the present invention is not limited to the one in which the separating members at both ends are conveying rollers, and at least one of the second separating members 75a ″ divided into a plurality of members is a biasing means. What is necessary is just to be a conveyance roller which is energized and press-contacts with the paper feed roller 72a, and can rotate.

As described above, according to the sheet material separating apparatus according to the third embodiment, the second separating member 75a ″ is divided into three separating members along the axial direction of the sheet feeding roller 72a, and these second members are separated. Of the separating members 75a ″, the central separating member 75a ₂ ′ has a separating pad 78a ₂ ′ as in the second embodiment, and can be elastically contacted or separated from the sheet feeding roller 72a and separated at both ends. Since the members are conveyance rollers 75a ₁ ″ and 75a ₃ ″, when a large conveyance force is required, such as using a strong sheet material such as thick paper or hard paper, either one of the paper supply rollers 72a or By forming a nip with both conveying rollers (75a ₁ ″, 75a ₃ ″), the sheet material conveying direction can be bent in a predetermined direction by reducing or eliminating the frictional force in the nip. Transfer force transmitted It can be diverted without loss smoothly in a predetermined conveying direction. Accordingly, it is possible to prevent problems in feeding the sheet material such as non-feeding, and to further reduce the occurrence of damage to the sheet material due to separation members such as rubbing and scratches.

  As described above, the color copying machine has been described as an example of the image forming apparatus according to the embodiment of the present invention. However, the image forming apparatus is not necessarily limited to such an example, and may be, for example, a monochrome printer or a FAX. The present invention can also be applied. In short, the present invention can be applied to an image forming apparatus including a frictional separation type paper feeding device including a manual paper feeding device.

  The image reading unit, the optical unit, the image forming unit, the transfer unit, the fixing unit, the paper discharge unit, the charging unit, the developing unit, the cleaning unit, etc. in the description of the embodiments are merely examples. Configurations of other known devices and means can be employed. Even in such a case, it is clear that the same effect can be achieved with respect to the problem. Further, the shapes, structures, and the like of the respective constituent members shown in the drawings are merely preferable examples, and it goes without saying that the design can be appropriately changed within the scope of the claims. Note that the frictional resistance used during the description of the separation pad, which is a friction member, refers to both the static friction coefficient and the dynamic friction coefficient.

1 Copying machine (image forming device)
7 Paper feeding unit (paper feeding device)
7a, 7b, 7c, 7d Sheet feeding trays 70a, 70a ', 70a "Sheet material separating devices 70b, 70c, 70d Sheet material separating device 71a Sheet material stacking table 72a Paper feeding roller 73a Energizing means (pressure contact mechanism)
74a First separation member 75a, 75a ′, 75a ″ Second separation member 75a ₁ ′, 75a ₂ ′, 75a ₃ ′ separation member (second separation member)
75a ₁ ", 75a _3" conveyor rollers (second separating member)
76a Coil spring (biasing means)
77a Separation pad (friction member)
78a Separation pad (friction member)
79a Coil spring (biasing means)
8 Manual feed section (paper feeder)
8a Manual feed tray 80a Sheet material separation device

JP-A-11-349167 JP 2002-68506 A JP 2007-137526 A JP 2004-155585 A JP 2003-292183 A

Claims (7)

A sheet material loading table on which a plurality of sheet materials are stacked, a sheet feeding roller that feeds the sheet material by rotating in contact with the sheet material, and a bundle of sheet materials loaded on the sheet material loading table A pressure contact mechanism that press-contacts the sheet feeding roller, and a first separation member that elastically contacts the sheet feeding roller to form a first separation nip, and a sheet material is provided in the first separation nip. In the sheet material separation device that separates and feeds one by one,
A second separation member that elastically contacts the downstream side of the first separation nip of the paper feed roller to form a second separation nip is provided so as to be elastically contacted or separated from the paper feed roller. Sheet material separating device.   The second separation member is divided into a plurality of separation members along the axial direction of the sheet feeding roller, and each separation member is individually elastically contacted or separated from the sheet feeding roller. The sheet material separating apparatus according to claim 1.   3. Each of the separation members of the second separation member has a friction member that elastically contacts the paper feeding roller in a second separation nip, and each friction member has a different friction coefficient. The sheet | seat material separation apparatus of description.   The second separation member has one end pivotally supported by the first separation member, and the other end swings to be elastically contacted or separated from the paper feed roller. The sheet | seat material separation apparatus in any one of 1 thru | or 3.   5. The transfer roller according to claim 2, wherein at least one of the second separation members is urged by an urging unit and is pressed against the sheet feeding roller to be a rotatable conveyance roller. The sheet | seat material separation apparatus of description.   A sheet feeding device comprising the sheet material separation device according to claim 1.   An image forming apparatus comprising the paper feeding device according to claim 6.

Images