JP6518495B2 - Sheet feeding apparatus and image forming apparatus provided with the same - Google Patents

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeding device and an image forming apparatus including the same, and more particularly, to a sheet feeding device for taking out and feeding sheets stacked on a sheet loading stand one by one and an image forming apparatus including the same.

  Patent Document 1 discloses an example of a conventional sheet feeding apparatus. The sheet feeding device of Patent Document 1 is a sheet feeding device adopting a roller separation system, and includes a pickup roller provided above the sheet feeding cassette, and a separating unit provided downstream of the pickup roller in the sheet feeding direction. Prepare. The separating unit includes a sheet feeding roller and a separating roller disposed opposite to each other across the sheet conveyance path, and the sheet feeding roller and the separating roller are in contact with each other to form a nip. Such a separating unit separates and conveys one sheet in contact with the sheet feeding roller among the sheets taken out by the pickup roller by utilizing the friction with the sheet.

JP, 2012-166912, A

  However, in the roller separation system as in the technique of Patent Document 1, the separation performance can not be said to be sufficient. For this reason, it is difficult to appropriately cope with the type of sheet, the surface condition of the roller, the difference in the environment, and the like, which may cause a separation error (double feed) of the sheet. Also, depending on the type of paper, it was necessary to change the setting of separation conditions individually.

  SUMMARY OF THE INVENTION Therefore, the main object of the present invention is to provide a novel sheet feeding device and an image forming apparatus provided with the same.

  Another object of the present invention is to provide a sheet feeding device and an image forming apparatus including the sheet feeding device, which are excellent in sheet separation performance and can appropriately feed sheets one by one.

A first invention is a sheet feeding device for feeding a sheet stacked on a sheet loading table , which is provided on the downstream side of a pickup roller for picking up the sheet from the sheet loading table and the pickup roller in the sheet conveyance direction A sheet feed roller for conveying the sheet taken out by the sheet, and the first roller and a second roller provided on the downstream side of the sheet conveyance direction of the first roller so as to contact the outer peripheral surface of the sheet feed roller An endless separation belt is provided , which separates the sheet conveyed by the sheet feeding roller into one sheet, and the sheet feeding roller connects the axis center of the first roller and the axis center of the second roller, The sheet feeding device is disposed between the first roller and the second roller, and disposed between the axial center of the first roller and the axial center of the second roller in the horizontal direction of the sheet feeding device. .

In the first aspect of the invention, the sheet feeding device is a device for taking out and feeding sheets stacked on the sheet loading stand one by one, and includes a pickup roller. On the downstream side of the pickup roller in the sheet conveyance direction, a sheet feeding roller for applying a propelling force to the sheet is provided, and at an opposing position of the sheet feeding roller, an endless separating belt as a separating member is provided. The separation belt is stretched around the first roller and the second roller, and the outer peripheral surface of the separation belt is disposed in contact with the outer peripheral surface of the sheet feeding roller. That is, a nip portion is formed between the paper feed roller and the separation belt, and the paper feed roller and the separation belt constitute a separation conveyance unit. The sheet feeding roller is disposed between the first roller and the second roller in a direction connecting the axial center of the first roller and the axial center of the second roller. The sheet feeding roller is disposed between the axial center of the first roller and the axial center of the second roller in the horizontal direction of the sheet feeding device.

  According to the first aspect of the invention, since the endless separation belt is used as the separation member, the width of the nip portion in the separation conveyance unit can be made large. That is, since the contact area between the sheet and the nip portion can be increased, the separation performance of the sheet is improved, and the sheets stacked on the sheet stacking table can be appropriately separated and supplied one by one.

  A second invention is according to the first invention, and the outer diameter of the first roller is set smaller than the outer diameter of the second roller.

  In the second invention, the outer diameter of the first roller is set smaller than the outer diameter of the second roller provided on the downstream side in the sheet conveyance direction.

  According to the second aspect of the present invention, it is possible to widen the sheet entry port of the nip portion while achieving thinning of the sheet feeding device. By widening the sheet entry port of the nip portion, the sheet can easily enter the nip portion, and the leading end of the sheet can be prevented from being broken at the nip portion.

A third invention is according to the first or second invention, and the width of the sheet feeding roller is larger than the width of the separation belt in the direction orthogonal to the sheet conveying direction.

  A fourth invention is an image forming apparatus including the sheet feeding device according to any one of the first to third inventions.

  According to the fourth aspect of the invention, the same effects as those of the first to third aspects of the invention can be obtained, and the separation performance of the sheets can be improved, and the sheets stacked on the sheet stacking table can be appropriately provided one by one. It can be supplied separately.

  According to the present invention, since the endless separation belt is used as the separation member, the width of the nip portion in the separation conveyance unit can be increased. That is, since the contact area between the sheet and the nip portion can be increased, the separation performance of the sheet is improved, and the sheets stacked on the sheet stacking table can be appropriately separated and supplied one by one.

  The above-described objects, other objects, features and advantages of the present invention will become more apparent from the detailed description of the following embodiments given with reference to the drawings.

FIG. 1 is a schematic cross-sectional view showing an internal structure of a multifunction peripheral provided with a sheet feeding device of a first embodiment of the present invention. FIG. 2 is an illustrative view schematically showing a sheet feeding device of FIG. 1; FIG. 2 is an illustrative view schematically showing the sheet feeding device of FIG. 1 as viewed from above; FIG. 6 is an illustrative view for explaining an arrangement of a sheet feeding roller and a separation belt in the sheet feeding device of FIG. 1; FIG. 6 is an illustrative view schematically showing a sheet feeding device of a second embodiment of the present invention; FIG. 10 is an illustrative view schematically showing a sheet feeding device of a third embodiment of the present invention;

[First embodiment]
Referring to FIG. 1, a sheet feeding apparatus 10 according to an embodiment of the present invention is an apparatus for taking out sheets (recording media) stacked on a sheet loading stand 70 one by one and feeding the sheet. , Facsimiles, printers, and image forming apparatuses such as these multifunction machines. As will be described in detail later, the sheet feeding device 10 includes a separating and conveying section (separating section) 80 constituted by the sheet feeding roller 82 and the separating belt 86, and adopts an endless separating belt 86 as a separating member The sheet taken out of the sheet stacking table 70 can be properly separated into one sheet. In this first embodiment, an example is shown in which the sheet feeding device 10 is applied to a multifunction peripheral (MFP) 100 having a copying function, a printer function, a scanner function, a facsimile function, and the like.

  First, the configuration of the MFP 100 will be schematically described. As shown in FIG. 1, the multifunction peripheral 100 includes a multifunction peripheral 12 having a sheet feeding device 10 and an image reading device 14 disposed thereabove.

  The image reading device 14 includes a document placement table 16 formed of a transparent material. A document holding cover 18 is attached to the upper side of the document placement table 16 via a hinge or the like so as to be openable and closable. The document holding cover 18 is provided with an automatic document feeder (ADF) 24 for automatically feeding the document placed on the document placement tray 20 to the image reading position 22 sheet by sheet. Further, on the front side of the document placement table 16, an operation unit (not shown) such as a touch panel and an operation button for receiving an input operation such as a print instruction from the user is provided.

  Further, the image reading device 14 incorporates an image reading unit 26 including a light source, a plurality of mirrors, an imaging lens, a line sensor, and the like. The image reading unit 26 exposes the surface of the document with a light source, and guides reflected light reflected from the surface of the document to an imaging lens by a plurality of mirrors. Then, the reflected light is imaged on the light receiving element of the line sensor by the imaging lens. The line sensor detects the luminance and the chromaticity of the reflected light formed on the light receiving element, and generates image data based on the image of the document surface. As the line sensor, a CCD (Charge Coupled Device), a CIS (Contact Image Sensor) or the like is used.

  A control unit (not shown) including a CPU, a memory, and the like, an image forming unit 30, and a sheet feeding device 10 are incorporated in the multifunction peripheral body 12. The control unit transmits control signals to each part of the multifunction device 100 in response to an input operation to an operation unit such as a touch panel, etc., and causes the multifunction device 100 to execute various operations.

  The image forming unit 30 includes an exposure unit 32, a developing device 34, a photosensitive drum 36, a cleaner unit 38, a charger 40, an intermediate transfer belt unit 42, a transfer roller 44, a fixing unit 46, etc. The image is formed on the sheet conveyed from the sheet feeding unit 50, and the sheet on which the image is formed is discharged to the sheet discharge tray 52. As image data for forming an image on a sheet, image data read by the image reading unit 26 or image data transmitted from an external computer is used.

  The image data handled by the multifunction device 100 corresponds to four color images of black (K), cyan (C), magenta (M) and yellow (Y). For this reason, each of the developing device 34, the photosensitive drum 36, the cleaner unit 38 and the charging device 40 is provided four by four so as to form four types of latent images corresponding to the respective colors, and thereby four image stations are provided. Configured

  The photosensitive drum 36 is an image carrier having a photosensitive layer formed on the surface of a conductive cylindrical substrate, and the charging device 40 is a member for charging the surface of the photosensitive drum 36 to a predetermined potential. is there. Further, the exposure unit 32 is configured as a laser scanning unit (LSU) including a laser emitting unit, a reflection mirror, etc., and exposes the surface of the charged photosensitive drum 36 to electrostatic latent light according to the image data. An image is formed on the surface of the photosensitive drum 36. The developing unit 34 visualizes the electrostatic latent image formed on the surface of the photosensitive drum 36 with toner of four colors (YMCK). The cleaner unit 38 also removes toner remaining on the surface of the photosensitive drum 36 after development and image transfer.

  The intermediate transfer belt unit 42 includes an intermediate transfer belt 54, a drive roller 56, a driven roller 58, four intermediate transfer rollers 60, and the like, and is disposed above the photosensitive drum 36. The intermediate transfer belt 54 is provided to be in contact with the respective photosensitive drums 36, and the toner images of the respective colors formed on the respective photosensitive drums 36 are sequentially superimposed on the intermediate transfer belt 54 using the intermediate transfer roller 60. The multi-color toner image is formed on the intermediate transfer belt 54 by the transfer. Further, a transfer roller 44 is disposed in the vicinity of the driving roller 56, and the toner formed on the intermediate transfer belt 54 as the sheet passes through the nip area between the intermediate transfer belt 54 and the transfer roller 44. The image is transferred to the paper.

  The fixing unit 46 includes a heat roller 62 and a pressure roller 64, and is disposed above the transfer roller 44. The heat roller 62 is set to have a predetermined fixing temperature, and when the sheet passes through the nip area between the heat roller 62 and the pressure roller 64, the toner image transferred to the sheet is melted. The toner image is thermally fixed to the sheet by mixing and pressing.

  Further, below the image forming unit 30, a sheet feeding device 10 for feeding a sheet to the image forming unit 30 is provided. In the first embodiment, the sheet feeding device 10 sequentially extracts and feeds the uppermost sheet among the sheets stacked on the sheet stacking table 70. The specific configuration of the sheet feeding device 10 will be described later.

  In the MFP main body 12, a first sheet for feeding the sheet from the sheet feeding device 10 or the manual sheet feeding portion 50 to the sheet discharge tray 52 via the registration roller 68, the transfer roller 44 and the fixing unit 46 is provided. A sheet conveyance path S1 is formed. Further, when performing duplex printing on a sheet, the sheet after single-sided printing is completed and passed through the fixing unit 46 is returned to the first sheet conveyance path S1 upstream of the transfer roller 44 in the sheet conveyance direction. The second sheet conveyance path S2 is formed. In the first sheet conveyance path S1 and the second sheet conveyance path S2, a plurality of conveyance rollers 66 for applying a propelling force to the sheets in an auxiliary manner are appropriately provided.

  When single-sided printing (image formation) is performed in the multifunction machine main body 12, the sheet is guided one by one to the first sheet conveyance path S 1 by the sheet feeding device 10 or the manual sheet feeding portion 50, and the conveyance roller 66 It is transported to. Then, the sheet is conveyed by the registration roller 68 to the transfer roller 44 at the timing when the leading end of the sheet and the leading end of the image information on the intermediate transfer belt 54 are aligned, and the toner image is transferred onto the sheet. Thereafter, by passing through the fixing unit 46, the unfixed toner on the sheet is melted and fixed by heat, and the sheet is discharged onto the sheet discharge tray 52 through the conveyance roller (sheet discharge roller) 66.

  On the other hand, when performing double-sided printing, when the rear end of the sheet having passed single-sided printing and passed through the fixing unit 46 reaches the sheet discharge roller 66 near the sheet discharge tray 52, reverse the sheet discharge roller 66. By rotating the sheet, the sheet reversely travels and is guided to the second sheet conveyance path S2. The sheet guided to the second sheet conveyance path S2 is conveyed by the conveyance roller 66 on the second sheet conveyance path S2, and is guided to the first sheet conveyance path S1 on the upstream side of the registration roller 68 in the sheet conveyance direction. At this point, the front and back of the sheet is reversed, and thereafter, the sheet passes through the transfer roller 44 and the fixing unit 46 to print on the back of the sheet.

  Subsequently, the configuration of the sheet feeding device 10 will be specifically described with reference to FIGS. 2 and 3. As shown in FIGS. 2 and 3, the sheet feeding device 10 is a device that picks up and feeds sheets stacked on a sheet stacking table 70 sheet by sheet, and includes a pickup roller 78 and a separation conveyance unit 80. The separation conveyance unit 80 is configured of a sheet feeding roller 82 and a separation belt 86.

  The sheet loading table (sheet feeding tray) 70 can be moved up and down by a driving unit or urging unit (not shown), and at the time of sheet feeding, the sheet is vertically moved so that the uppermost sheet has a predetermined height regardless of the sheet loading amount. Be moved. In addition, a front plate 72, a rear plate 74, and a pair of side plates 76 are provided at the periphery of the sheet stacking table 70. The front plate 72 functions as a guide plate that regulates the front end of the sheets stacked on the sheet stacking table 70 in the sheet conveyance direction and guides the uppermost sheet to be conveyed along the outer peripheral surface of the separation belt 86 Do. The rear plate 74 regulates the rear end of the sheets stacked on the sheet stacking table 70 in the sheet conveyance direction, and is provided movably in the front-rear direction in the sheet conveyance direction. Further, the side plate 76 regulates each of the sheet edges in the direction (sheet width direction) orthogonal to the sheet conveyance direction of the sheets stacked on the sheet stacking table 70, that is, both side ends of the sheets. It is provided to be movable.

  A pick-up roller 78 for picking up the uppermost sheet from the sheet stacking table 70 is provided above the downstream end of the sheet stacking table 70 in the sheet conveyance direction. Further, on the downstream side of the pickup roller 78 in the sheet conveyance direction, a sheet feed roller 82 for applying a propelling force to the sheet is provided. The outer diameters of pickup roller 78 and sheet feeding roller 82 are, for example, 26 mm.

  The pickup roller 78 and the feed roller 82 are unitized by the first frame 84, and the shafts of the pickup roller 78 and the feed roller 82 are rotatably supported by the first frame 84. The respective axes of the pickup roller 78 and the paper feed roller 82 are connected to a drive source (motor) (not shown), and the drive force from the drive source is transmitted to the respective axes. Will rotate.

  Further, a separation belt 86 is provided at a position opposite to the paper feed roller 82. The separation belt 86 is a separation member for separating sheets conveyed by the paper feed roller 82 into one sheet, and as described above, the separation conveyance unit 80 is separated by the separation belt 86 and the paper feed roller 82. Configured

  Specifically, the separation belt 86 is endlessly formed of rubber, synthetic resin or the like, and is stretched around the first roller 88 and the second roller 90. The first roller 88 is disposed upstream of the sheet feeding roller 82 in the sheet conveyance direction, and the second roller 90 is disposed downstream of the sheet conveyance direction. The outer diameters of the first roller 88 and the second roller 90 are, for example, 26 mm. Further, the first roller 88 and the second roller 90 are unitized by the second frame 92, and the axes of the first roller 88 and the second roller 90 are rotatably supported by the second frame 92.

  The outer peripheral surface of the separation belt 86 is in contact with the outer peripheral surface of the paper feed roller 82 with a predetermined pressure (separation pressure), and a nip portion 94 is formed between the paper feed roller 82 and the separation belt 86. Ru. For example, an urging member such as a compression spring (not shown) is connected to the shaft of the sheet feeding roller 82, and the sheet feeding roller 82 is urged to abut against the separation belt 86 at a predetermined pressure by this urging member. . However, the biasing member may be connected to the shafts of the first roller 88 and the second roller 90.

  Further, at least one of the first roller 88 and the second roller 90 is a driving roller connected to a driving source (not shown). In the first embodiment, the second roller 90 is a drive roller, and the first roller 88 is a driven roller. The separation belt 86 can be moved circumferentially as the second roller 90 is driven to rotate.

  Specifically, the second roller 90 is provided with a torque limiter (not shown), and the axis of the second roller 90 is in the direction of returning the sheet to the upstream side (the sheet stacking table 70 side) in the sheet conveyance direction. A rotational drive force is applied from the drive source. Then, when only one sheet of paper passes through the nip portion 94, the separation belt 86 is driven to follow the feed roller 82, and the second roller 90 is driven to rotate by the slippage of the torque limiter, thereby causing the sheet It sends out to the downstream side in the transport direction as it is. On the other hand, when two sheets of paper are double-fed to the nip portion 94, the rotational driving force of the second roller 90 overcomes the frictional force between the sheets and rotates in the direction to return the sheets. The separation belt 86 circulates along with the rotational drive, and the lower sheet in contact with the separation belt 86 is returned to the sheet stacking table 70 side. As a result, only the upper sheet in contact with the sheet feed roller 82 is separated and conveyed to the downstream side.

  Here, as shown in FIG. 4, the arrangement position of each roller included in the sheet feeding device 10 is the distance X1 between the sheet feeding surface (conveying path) of the sheet taken out by the pickup roller 78 and the top of the first roller 88. The distance X2 is preferably 3 to 7 mm, and the distance X2 between the sheet feeding surface of the sheet and the bottom of the sheet feeding roller 82 is preferably 3 to 7 mm. Further, the inclination angle θ of the upper surface of the separation belt 86 with respect to the sheet feeding surface of the sheet is preferably set to 35 ° or less. By arranging each roller in this manner, the sheet taken out by the pickup roller 78 is smoothly guided to the nip portion 94 of the separating and conveying unit 80, and the separating and feeding performance is appropriately exhibited. In addition, the sheet feeding device 10 can be thinned.

  In the sheet feeding device 10 as described above, the sheet taken out of the sheet stacking table 70 by the pickup roller 78 is separated and conveyed by passing through the nip portion 94 of the separating and conveying unit 80 and is conveyed to the first sheet conveying path S1. It is eaten. That is, when only one sheet of paper is conveyed to the nip portion 94, the sheet is guided to the first sheet conveyance path S1 as it is. On the other hand, when the sheets are double-fed to the nip portion 94, the lower sheet contacting the separation belt 86 is returned to the sheet stacking table 70 side, and only the upper sheet contacting the sheet feeding roller 82 It is separated and guided to the first sheet conveyance path S1.

  Under the present circumstances, in this 1st Example, since the endless separation belt 86 was adopted as a separation member of the separation conveyance part 80, the outer peripheral surface of the paper feeding roller 82 and the outer peripheral surface of the separation belt 86 were pressure-welded. At the same time, the shape of the separation belt 86 can be curved and deformed along the outer peripheral surface of the paper feed roller 82. As a result, the contact length between the sheet feed roller 82 and the separation belt 86 in the sheet conveyance direction, that is, the width (nip area) of the nip portion 94 can be increased. Therefore, the separation performance of the sheet in the separation conveyance unit 80 is improved as compared to using the separation roller as the separation member.

  As described above, according to the first embodiment, since the endless separation belt 86 is used as the separation member, the width of the nip portion 94 in the separation conveyance unit 80 can be made large. That is, since the contact area between the sheet and the nip portion 94 can be increased, the sheet separation performance is improved, and the sheets stacked on the sheet stacking table 70 can be appropriately separated and supplied one by one.

Second Embodiment
Next, with reference to FIG. 5, a sheet feeding device 10 according to a second embodiment of the present invention will be described. In the second embodiment, the size of the first roller 88 which bridges the separation belt 86 is different from that of the first embodiment described above. The configuration of the other parts is the same, so parts common to those in the first embodiment described above are denoted by the same reference numerals, and redundant description will be omitted or simplified.

  As shown in FIG. 5, the sheet feeding device 10 includes a separating and conveying unit 80 configured by a sheet feeding roller 82 and an endless separation belt 86. The separation belt 86 is stretched around a second roller 90 provided on the downstream side of the first roller 88 and the first roller 88 in the sheet conveyance direction so that the outer peripheral surface thereof contacts the outer peripheral surface of the paper feed roller 82. Be Thus, a nip portion 94 is formed between the sheet feed roller 82 and the separation belt 86.

  In the second embodiment, the outer diameter of the first roller 88 is set smaller than the outer diameter of the second roller 90. The outer diameter of the first roller 88 is, for example, 20 mm, and the outer diameter of the second roller 90 is, for example, 26 mm.

  Here, from the viewpoint of thinning the sheet feeding device 10, the outer diameters of the first roller 88 and the second roller 90 are preferably smaller. However, when the outer diameters of the first roller 88 and the second roller 90 are reduced, the distance between the upper (nip portion 94 side) portion and the lower (return side) portion of the separation belt 86 is narrowed. There is a risk that the upper and lower portions may interfere with each other. Further, in order to prevent the sheet from being broken at the time of entry into the nip portion 94, the sheet entry port 96 of the nip portion 94 is preferably wide. However, if the position of the first roller 88 is moved downward to widen the sheet entry port 96 while the outer diameter of the first roller 88 is large, the thickness of the sheet feeding device 10 in the vertical direction becomes large.

  Therefore, in the second embodiment, in order to maintain the distance between the upper portion and the lower portion of the separation belt 86, the diameter of only one of the first roller 88 and the second roller 90 is reduced. did. When the diameter of one of the rollers is reduced, the diameter of the first roller 88 is reduced so that thinning of the sheet feeding device 10 can be achieved even if the sheet entry port 96 of the nip portion 94 is expanded. did.

  According to the second embodiment, as in the first embodiment, since the endless separation belt 86 is used as the separation member, the width of the nip portion 94 in the separation conveyance unit 80 can be increased. Therefore, the sheet separation performance is improved, and the sheets stacked on the sheet stacking table 70 can be appropriately separated and supplied one by one.

  Further, according to the second embodiment, since the outer diameter of the first roller 88 is set smaller than the outer diameter of the second roller 90, it is possible to reduce the thickness of the sheet feeding device 10 and to push the sheet in the nip portion 94. The mouth 96 can be spread. By widening the sheet entry port 96 of the nip portion 94, the sheet can easily enter the nip portion 94, and the leading end of the sheet can be prevented from being broken at the nip portion 94.

Third Embodiment
Next, with reference to FIG. 6, a sheet feeding device 10 according to a third embodiment of the present invention will be described. The third embodiment is different from the first and second embodiments in that the arrangement position of the separation belt 86 with respect to the paper feed roller 82 is different. The configuration of the other parts is the same, so parts common to the first embodiment and the second embodiment described above are denoted by the same reference numerals, and redundant description will be omitted or simplified.

  As shown in FIG. 6, the sheet feeding device 10 includes a separating and conveying unit 80 configured by a sheet feeding roller 82 and an endless separation belt 86. The separation belt 86 is stretched around the first roller 88 and the second roller 90 so that the outer peripheral surface thereof is in contact with the outer peripheral surface of the paper feed roller 82. Thus, a nip portion 94 is formed between the sheet feed roller 82 and the separation belt 86.

  In the third embodiment, the sheet feeding roller 82 is disposed closer to the second roller 90 than the first roller 88. That is, when a perpendicular line is drawn from the axial center of the feed roller 82 with respect to a line connecting the axial center of the first roller 88 and the axial center of the second roller 90, the perpendicular line from the axial center of the first roller 88 The distance Y1 to the foot is larger than the distance Y2 from the axial center of the second roller 90 to the foot of the perpendicular. As a result, the belt portion 86a on the upstream side of the sheet conveyance direction with respect to the nip portion 94 of the separation belt 86 becomes wider, so it becomes possible to pre-separate the sheet before entering the nip portion 94. Paper separation performance is further improved.

  According to the third embodiment, as in the first embodiment, since the endless separation belt 86 is used as the separation member, the width of the nip portion 94 in the separation conveyance unit 80 can be increased. Therefore, the sheet separation performance is improved, and the sheets stacked on the sheet stacking table 70 can be appropriately separated and supplied one by one.

  Further, according to the third embodiment, since the sheet feeding roller 82 is disposed closer to the second roller 90 than the first roller 88, pre-separation of sheets can be appropriately performed. Separation performance is further improved.

  In the multifunction machine (image forming apparatus) 100 shown in FIG. 1, only one sheet stacking table 70 and the sheet feeding device 10 are provided below the image forming unit 30, but the sheet stacking provided in the image forming apparatus The number of trays 70 and the number of sheet feeding devices 10 are arbitrary.

  In each of the above-described embodiments, the sheet feeding device 10 is applied to the mechanism for feeding from the sheet stacking table (sheet feeding tray) 70 disposed in the MFP main body 12, but the present invention is not limited thereto. For example, the sheet feeding device 10 can be applied to a mechanism (a manual sheet feeding unit) for feeding a sheet from a manual sheet feeding tray. Further, the sheet feeding device 10 can be applied to a large capacity sheet feeding device which is externally attached to the image forming apparatus and accommodates a large amount of sheets to be fed to the image forming apparatus. Furthermore, the sheet feeding apparatus 10 is applied not only to a mechanism for feeding a sheet (recording medium) on which an image is printed but also to a mechanism (for example, an automatic document feeder) for feeding a sheet (document) on which an image is read. It can also be done.

  Furthermore, in each of the above-described embodiments, as the separation belt 86, one that circulates in the direction of returning the sheet to the sheet stacking table 70 when the sheet is double-fed is used, but the invention is not limited thereto. For example, a separation belt can be used that separates the paper by stopping the orbital movement when the paper is double fed.

  In each of the above-described embodiments, the pickup roller 78 is fixedly installed. However, the pickup roller 78 may be configured to be vertically pivotable, for example, with the paper feeding roller 82 as a support shaft.

  The above-described specific numerical values such as dimensions are merely examples, and can be changed as appropriate according to the product specifications and the like.

DESCRIPTION OF SYMBOLS 10 ... Paper feeding apparatus 12 ... Multifunction machine main body 14 ... Image reading apparatus 30 ... Image formation part 70 ... Paper loading stand 78 ... Pickup roller 80 ... Separation conveyance part 82 ... Paper feeding roller 86 ... Separation belt 88 ... 1st roller 90 ... Second roller 94 ... nip portion 100 ... complex machine (image forming apparatus)

Claims (4)

A sheet feeding device for feeding sheets stacked on a sheet loading table, which
A pick-up roller for taking out the sheet from the sheet loading table ;
A paper feed roller provided downstream of the pickup roller in the paper conveyance direction, for conveying the paper picked up by the pickup roller, and a first roller and a second roller provided downstream of the first roller in the paper conveyance direction And an endless separation belt which is provided to contact the outer peripheral surface of the sheet feeding roller and separates the sheet conveyed by the sheet feeding roller into one sheet .
The paper feed roller is disposed between the first roller and the second roller in a direction connecting the axial center of the first roller and the axial center of the second roller, and A sheet feeding device , which is disposed between an axial center of the first roller and an axial center of the second roller in a horizontal direction .   The sheet feeding device according to claim 1, wherein an outer diameter of the first roller is set smaller than an outer diameter of the second roller. In a direction perpendicular to the sheet conveyance direction, the width of the paper feed roller is greater than the width of the separation belt, sheet feeding apparatus according to claim 1 or 2 wherein.   An image forming apparatus comprising the sheet feeding device according to any one of claims 1 to 3.

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