JP2016088745A - Sheet feeder and image formation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet feeder capable of stably feeding even a sheet which is not uniform in thickness, and an image formation device.SOLUTION: A mount plate 105 is provided with an auxiliary tray 101 to be mounted with sheets swingably on a fulcrum 101a of swing, and also provided with a roll 115 on a width-directional side of a pickup roller 102. When the mount plate 105 is elevated by elevation means, the sheets mounted on the auxiliary tray 101 are pressed by the roll 115 above a lower end of the pickup roller 102 so as to correct a tilt of a top sheet St, thereby making the top sheet St abut on the pickup roller 102 along.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a sheet feeding apparatus and an image forming apparatus, and relates to a configuration for feeding a sheet having a non-uniform thickness such as an envelope.

  2. Description of the Related Art Today, image forming apparatuses such as copying machines, printers, facsimiles, and the like that form an image on a sheet fed by a sheet feeding apparatus are widely used. As the sheet feeding apparatus, a sheet feeding cassette for storing sheets is detachably mounted in the apparatus main body, and sheets stored in the sheet feeding cassette are automatically fed by a pickup roller provided in the apparatus main body. It is common.

  Here, as such a sheet feeding apparatus, the sheet placed on the placing plate of the sheet feeding cassette is fed against the pickup roller so as to feed the sheet, so that the placing plate is freely raised by the raising portion. There is something. Note that the sheet feeding cassette regulates the position of the upstream end (hereinafter referred to as the trailing end) of the sheet feeding direction of the sheet placed on the placing plate so that sheets of different sizes can be stored. The rear end regulating portion is slidably provided. In addition, the sheet feeding cassette is provided with a pair of side end regulating portions that regulate the side end position of a sheet placed on the placement plate in a direction orthogonal to the sheet feeding direction (hereinafter referred to as the width direction). ing.

  When feeding the sheet, first, the pair of side end regulating portions regulates the side edge of the sheet on the placement plate, and the rear end regulation portion regulates the rear end of the sheet on the placement plate. The sheet is positioned at a predetermined position. Next, the placing plate is raised by the raising portion, the pickup roller is pressed against the sheet positioned on the placing plate, and then the pickup roller is rotated to feed the sheet.

  By the way, conventionally, in a sheet feeding apparatus, a sheet such as an envelope having a non-uniform thickness may be fed. In this case, when a plurality of sheets are placed on the placement plate, the height of the sheet bundle is not uniform. For this reason, when the loading plate is raised and the sheet is pressed against the pickup roller, one end in the width direction of the pickup roller comes into contact with the upper surface of the sheet, and the sheet feeding pressure becomes nonuniform. As a result, sheet feeding failure due to insufficient sheet feeding pressure, and sheet conveyance failure such as skewing or jamming occur. The sheet feeding pressure is a pressure for feeding the sheet when the pickup roller rotates in pressure contact with the sheet.

  Therefore, conventionally, an auxiliary tray is provided on the placing plate so as to be able to swing, and a sheet is placed on the auxiliary tray so that the uppermost sheet of the sheet bundle on the auxiliary tray can follow the pickup roller. The thing is proposed (refer patent document 1). Here, when a swingable auxiliary tray is provided, when the sheet is placed on the auxiliary tray and the placing plate rises and the uppermost sheet contacts the pickup roller, the pickup roller assists through the sheet. Power is applied to the tray. As a result, the auxiliary tray swings, and accordingly, the uppermost sheet comes into contact with the pickup roller evenly.

JP-A-9-86678

  By the way, in the sheet feeding apparatus provided with the auxiliary tray, when a sheet having a non-uniform thickness is placed on the auxiliary tray, the sheet S has a pair of side end regulating plates 104F, as shown in FIG. There is a case where only one of the side end regulating plates 104R out of 104R comes into contact. In this case, when the placement plate 105 is lifted, the sheet S is lifted up in a state where resistance is received by contact with the side end regulating plate 104R as shown in FIG.

  Thus, the sheet S receives resistance from the side end regulating plate 104R, the auxiliary tray 101 receives the resistance force F from the sheet S, and swings clockwise about the swing support point 101a, and the uppermost sheet St picks up. One end 102a of the roller 102 in the width direction comes into contact with one end. Here, when the pickup roller 102 comes into contact with the uppermost sheet St, a counterclockwise moment is generated on the auxiliary tray 101 with the swinging fulcrum 101a as a fulcrum via the sheet S, and this moment causes the auxiliary tray 101 to counterclockwise. Try to swing around.

  The magnitude of this moment is determined by the distance Xp in the width direction between the swing fulcrum 101a of the auxiliary tray 101 and the one end 102a in the width direction of the pickup roller 102. For this reason, when the distance Xp is short, the auxiliary tray 101 is swung counterclockwise to a position where the pick-up roller 102 can be removed from one side (a position where the uppermost sheet contacts the pickup roller evenly). I can't. In this case, since the sheet is fed in a state where the one-sided contact is not eliminated, a sheet feeding failure occurs.

  Accordingly, the present invention has been made in view of such a situation, and an object thereof is to provide a sheet feeding apparatus and an image forming apparatus that can stably feed a sheet having a non-uniform thickness. To do.

  In the sheet feeding apparatus, the present invention provides a lifting member that can be moved up and down, a swinging placement portion that is provided on the lifting member so as to be swingable about a swinging fulcrum, and on which the sheet is placed, and the swinging member A sheet feeding means that is provided above the placement section and feeds the sheet placed on the swing placement section in contact with the sheet; and a sheet feeding means for feeding the sheet placed on the swing placement section. A side end regulating member for regulating a side end position in the width direction orthogonal to the feeding direction, and the elevating member can be fed by the sheet feeding means at the uppermost position of the sheet placed on the swinging placing portion. A lifting means that raises to a certain position, and a sheet placed on the swing placement portion when the lifting member is lifted by the lifting means. , The contact is above the lower end of the sheet feeding means at a position where the sheet can be fed. Characterized by comprising a presser means which ability to.

  As in the present invention, when the elevating member is raised, the pressing means can abut on the sheet placed on the swinging placing portion above the lower end of the sheet feeding means, so that the uppermost sheet By correcting the inclination of the sheet, even a sheet having a non-uniform thickness can be stably fed.

1 is a diagram illustrating a configuration of a laser printer that is an example of an image forming apparatus including a sheet feeding device according to a first embodiment of the present invention. The side view which shows the structure of the said sheet feeding apparatus. FIG. 3 is a top view illustrating a configuration of the sheet feeding device. The control block diagram of the said sheet feeding apparatus. 6 is a flowchart illustrating sheet feeding operation control by a control unit provided in the sheet feeding apparatus. FIG. 3 is a cross-sectional view in the direction B of FIG. 2 showing a state before feeding of a sheet with a non-uniform thickness of the sheet feeding device is started. The figure which shows the state which the sheet | seat with non-uniform thickness contact | connected the roller of the said sheet feeding apparatus. The figure which shows the state when feeding the sheet | seat in which the thickness of the said sheet feeding apparatus is not uniform. The side view which shows the structure of the sheet feeding apparatus which concerns on the 2nd Embodiment of this invention. The figure which shows the state when feeding the sheet | seat in which the thickness of the said sheet feeding apparatus is not uniform. (A) of the conventional sheet feeding apparatus is a diagram showing a state before the mounting plate in a state where a non-uniform thickness sheet is mounted, and (b) is a pickup in which the mounting plate is raised. The figure which shows a state when a sheet | seat contact | abuts on the roller.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram illustrating a configuration of a laser printer that is an example of an image forming apparatus including a sheet feeding device according to a first embodiment of the present invention. As shown in FIG. 1, an image forming unit 20 that forms an image on a sheet S is provided in a laser printer main body (hereinafter referred to as a printer main body) 201 that is an image forming apparatus main body of a laser printer (hereinafter referred to as a printer) 200. It has been. In addition, the printer main body 201 is provided with a sheet feeding device 100 that feeds the sheets S stored in the paper feed cassette 106, and a manual feed portion 60 is provided on one side of the printer main body 201. .

  The image forming unit 20 includes a scanner unit 20a, a photosensitive drum 21a, and the like, and forms four toner images of four colors of yellow (Y), magenta (M), cyan (C), and black (Bk). A process cartridge 21 is provided. In addition, the image forming unit 20 includes an intermediate transfer unit 30 disposed above the process cartridge 21.

  The intermediate transfer unit 30 includes an intermediate transfer belt 31 wound around a driving roller 32, a tension roller 32a, and a driven roller 32b. The intermediate transfer unit 30 includes a primary transfer roller 33 provided inside the intermediate transfer belt 31 and abutting against the intermediate transfer belt 31 at a position facing the photosensitive drum 21a. Here, the intermediate transfer belt 31 is disposed so as to be in contact with each photosensitive drum 21a, and is rotated in the direction of arrow A by a driving roller 32 driven by a driving unit (not shown). Then, by applying a positive transfer bias to the intermediate transfer belt 31 by the primary transfer roller 33, each color toner image having a negative polarity on the photosensitive drum is sequentially transferred to the intermediate transfer belt 31 in a multiple transfer manner. As a result, a full-color image is formed on the intermediate transfer belt.

  A secondary transfer roller 34 constituting a secondary transfer unit that transfers a full-color image formed on the intermediate transfer belt to the sheet S is provided at a position facing the driving roller 32 of the intermediate transfer unit 30. . Further, a fixing unit 40 is disposed above the secondary transfer roller 34, and a discharge roller pair 52 is disposed downstream of the fixing unit 40 in the sheet conveyance direction. As shown in FIG. 1, a door 70 is provided on the side surface of the printer main body 201 so as to be openable and closable when jamming of a sheet occurs in a registration roller pair 12 or the like described later. . The printer main body 201 is provided with a control unit 110 that controls an image forming operation of the image forming unit 20, a sheet feeding operation of the sheet feeding apparatus 100, and the like.

  Next, an image forming operation of the printer 200 configured as described above will be described. When the image forming operation is started, first, the scanner unit 20a irradiates a laser beam based on image information from a personal computer (not shown), and the photosensitive drum 21a whose surface is uniformly charged with a predetermined polarity and potential. The surface is sequentially exposed to form an electrostatic latent image on the photosensitive drum. Thereafter, the electrostatic latent image is developed with toner and visualized. Then, yellow (Y), magenta (M), cyan (C) and black (Bk) toner images on the photosensitive drum are transferred to the intermediate transfer belt 31 by a transfer bias applied to the primary transfer roller 33. Transfer is performed to form a full-color toner image on the intermediate transfer belt 31. The toner remaining on the photosensitive drum is collected in a waste toner container (not shown) by a cleaning unit (not shown) provided in the process cartridge 21.

  In parallel with this toner image forming operation, the sheet S accommodated in the paper feed cassette 106 is sent out by a pickup roller (feed roller) 102. Next, the sheet S is separated one by one by a separation unit including a conveyance roller 107 and a separation roller 108 that is in pressure contact with the conveyance roller 107, and then stopped by the conveyance roller 11. It is conveyed to. Then, the sheet S forms a loop with the registration roller pair 12 in a stopped state, thereby correcting the direction of the leading edge and correcting skew.

  Next, in the secondary transfer unit, the registration roller pair 12 is driven so that the front end of the sheet S whose skew has been corrected and the full color toner image on the intermediate transfer belt are aligned, and the sheet S is transferred to the secondary transfer unit. To the center. Then, the full-color toner image is collectively transferred onto the sheet S by the secondary transfer bias applied to the secondary transfer roller 34 in the secondary transfer unit.

  Next, the sheet S on which the full-color toner image has been transferred is conveyed to the fixing unit 40, and the toner of each color is melted and mixed by receiving heat and pressure by the fixing roller pair 41 provided in the fixing unit 40. The toner image on S is fixed as a full color image. Thereafter, the sheet S on which the toner image is fixed is discharged by a discharge roller pair 52 to a paper discharge mounting table 202 provided on the upper surface of the printer main body.

  On the other hand, when the sheet is manually fed by the manual feeding unit 60, the sheet placed on the multi-feed tray 61 that supports the manual sheet is fed by the manual feed roller 62. After that, the sheet is conveyed to the secondary transfer unit by the conveying roller 11 and the registration roller pair 12 and the full color toner image is transferred similarly to the sheet fed by the sheet feeding device 100, and then the sheet discharge table. The paper is discharged to 202. In FIG. 1, an arrow A indicates a conveyance path until the sheet S fed from the paper feed cassette 106 is discharged onto the paper discharge platform 202.

  FIG. 2 is a side view illustrating the configuration of the sheet feeding apparatus 100. As shown in FIG. 2, the sheet feeding apparatus 100 includes a sheet feeding cassette 106 that is a sheet storing unit, and a feeding unit 10 that separates and feeds sheets S stored in the sheet feeding cassette 106 one by one. Yes. Here, the paper feed cassette 106 includes a cassette main body 106a that is a main body of the sheet storage unit, a mounting plate 105 that is provided in the cassette main body 106a, and that rotates in the vertical direction around a rotation fulcrum 105a, and a mounting plate 105. Is provided with a rising plate 109.

  The ascending plate 109 is a mounting plate that is an elevating member that can be moved up and down about the rotation fulcrum 109a by transmitting the drive of the lifter drive motor M1 by a drive transmission means (not shown). 105 is raised. The ascending plate 109, the lifter driving motor M1, and a driving transmission means (not shown) constitute the ascending means 10a that raises the placing plate 105 to a position where the sheet comes into contact with the pickup roller 102 as the sheet feeding means. Is done.

  Here, in the present embodiment, the sheet feeding apparatus 100 feeds a sheet in which the thickness on one end side is thicker than the thickness on the other end side opposite to the one end side and the thickness of the envelope or the like is not uniform. Like to do. For this reason, an auxiliary tray 101 that is a swinging mounting portion is swingably attached to the mounting plate 105 so that a sheet having a non-uniform thickness such as an envelope can be fed.

  Further, the paper feed cassette 106 is provided with a rear end regulating plate 129 for regulating the position of the upstream end (hereinafter referred to as the rear end) of the sheet S in the sheet feeding direction of the sheet S set on the loading plate 105 or the auxiliary tray 101. It has been. Further, as shown in FIG. 3 which is a top view of the sheet feeding apparatus 100, the sheet feeding cassette 106 has a pair of side end positions that regulate a side end position in a direction orthogonal to the sheet feeding direction (hereinafter referred to as a width direction). A side end regulating plate 104 (104F, 104R) which is a side end regulating member is provided. The side end regulating plate 104 and the rear end regulating plate 129 are supported so as to be slidable in the directions V1 and V2, respectively, and are set at a position suitable for the sheet size.

  On the other hand, the feeding unit 10 includes a pickup roller 102, a conveyance roller 107, and a separation roller 108 that constitutes a separation unit that is in pressure contact with the conveyance roller 107 and separates a sheet. The transport roller 107 rotates as the drive shaft 107A rotates by the drive of the paper feed motor M2 shown in FIG. 3 that is transmitted through a drive transmission means (not shown).

  Here, as shown in FIG. 3, a first idler gear 114 is attached to the drive shaft 107A, and an elevating plate 111 for rotating the pickup roller 102 in the vertical direction about the drive shaft 107A is rotated. Supported as possible. The lift plate 111 is provided with an idler shaft 113A, and a second idler gear 113 that meshes with the first idler gear 114 is rotatably attached to the idler shaft 113A.

  The lift plate 111 is provided with a pickup roller support shaft 1021. The pickup roller support shaft 1021 rotatably holds a third idler gear 112 that meshes with the second idler gear 113, a pickup roller 102, and a roller 115 as a rotating body that is an example of a pressing unit. The roller 115 will be described later.

  A coupling mechanism (not shown) that transmits the rotation of the third idler gear 112 to the pickup roller 102 is provided between the third idler gear 112 and the pickup roller 102. Thus, when the drive shaft 107A rotates, the third idler gear 112 rotates via the first idler gear 114 and the second idler gear 113, and the pickup roller 102 rotates due to the rotation of the third idler gear 112.

  Here, the elevating plate 111 is urged downward by a pressure spring 116 shown in FIG. 2, and is pressed by the pressure spring 116 and abuts against a stopper (not shown) when the sheet is fed. When the elevating plate 111 is in contact with the stopper in this way, the pickup roller 102 is positioned at the lower limit position of the movable range.

  Further, when the paper feed cassette 106 is pulled out from the printer main body 201, the elevating plate 111 is moved upward by a link mechanism (not shown) interlocked with the paper feed cassette 106 that is pulled out so as not to hinder the drawer of the paper feed cassette 106. Be raised. When the paper feed cassette 106 is attached to the printer main body 201, the pulling up by the link mechanism is released, the lifting plate 111 is lowered, and the pickup roller 102 is moved to the lower limit position of the movable range.

  4 is a control block diagram of the sheet feeding apparatus 100. As shown in FIG. 4, the control unit 110 includes a lifter driving motor M1, a conveying roller 107, and a pickup roller 102 for raising the placing plate 105. A sheet feeding motor M2 to be rotated is connected. Also, a cassette attachment / detachment detection sensor 120 for detecting attachment / detachment of the paper feed cassette 106 and a paper surface height detection sensor 121 for detecting the height of the paper surface of the sheet on the mounting plate 105 that rises as the mounting plate 105 rises are connected. ing.

  Next, the sheet feeding operation control for the sheet feeding apparatus 100 by the control unit 110 will be described with reference to the flowchart shown in FIG. First, when the sheet cassette 106 storing sheets is stored in the printer main body 201 and the cassette attachment / detachment detection sensor is turned on (Y in S2), the control unit 110 turns on the lifter drive motor M1 (S3). A lift-up operation for raising the mounting plate 105 is started. When the paper feed cassette 106 is mounted on the printer main body 201, the pickup roller 102 moves to the lower limit position of the movable range.

  Then, when the placement plate 105 moves up with the pickup roller 102 moved to the lower limit position of the movable range, the uppermost sheet of the sheet bundle placed on the placement plate 105 eventually pushes up the pickup roller 102. Here, the pickup roller 102 is pushed up, and the paper surface height detection sensor 121 is turned on (Y in S4). When the paper surface height detection sensor 121 is turned on, the control unit 110 stops the lifter drive motor M1 (S5). ), Lifting up of the mounting plate 105 is completed. When the lift-up of the mounting plate 105 is completed, the pickup roller 102 is in a position where it can feed the uppermost sheet by contacting the uppermost surface of the mounted sheet. As a result, the pickup roller 102 stops at the standby position, and the sheet feeding apparatus 100 is ready to start a print job.

  Next, the control unit 110 waits for a start signal for starting paper feeding from an operation unit (not shown), and when the start signal is input and the start of paper feeding is determined (Y in S6), The drive of the paper motor M2 is started (S7). As a result, the drive shaft 107A rotates, and accordingly, the first idler gear 114, the second idler gear 113, and the third idler gear 112 rotate, the pickup roller 102 rotates, and the sheet is fed. Thereafter, when feeding of a predetermined number of sheets in the job is completed (Y in S8), the control unit 110 stops driving the sheet feeding motor M2 (S9). In this embodiment, the control for continuously feeding sheets at the position where the pickup roller 102 is lowered until the job is completed is described. However, every time the sheet is fed out during the job, the pickup roller 102 is fed. Control to move up and down may be used.

  By the way, in the present embodiment, as described above, the auxiliary tray 101 is attached to the mounting plate 105, and when storing a non-uniform thickness sheet such as an envelope, the thickness is non-uniform. Is set on the mounting plate 105. Here, the auxiliary tray 101 is provided at the center in the width direction of the bottom surface as shown in FIG. 6 which is a cross-sectional view in the B direction of FIG. 2, and is a swing fulcrum 101a configured by a convex portion extending in the sheet feeding direction. Oscillates clockwise and counterclockwise around fulcrum.

  In this embodiment, as shown in FIG. 6, the roller 115 is supported on the pickup roller support shaft 1021 so as to be rotatable in the axial direction with respect to the pickup roller 102. That is, the idler gear 112 and the roller 115 that is a rotating body are coaxially arranged on both sides of the pickup roller 102 in the axial direction.

  In FIG. 6, X0 indicates the distance in the width direction from the end 115a of the roller 115 opposite to the pickup roller 102 to the center of the pickup roller 102 (also coincides with the swinging fulcrum 101a of the auxiliary tray). Yes. X1 is a distance between the inner wall surface 104a facing the sheet of the side end regulating plate 104 and the center position of the pickup roller 102 when a sheet having the longest length in the width direction among the sheets to be placed is set. Is shown. In this embodiment, the distance X0> the distance X1.

  In other words, in the present embodiment, the end 115 a of the roller 115 opposite to the pickup roller 102 is positioned on the outer side in the width direction than the inner wall surface 104 a of the side end regulating plate 104. And by comprising in this way, when the sheet | seat S raises, a sheet | seat can be made to contact | abut to the roller 115. FIG.

  Here, as shown in FIG. 6, the mounting plate 105 is lifted in a state where the sheet S is mounted in a state where the height is not uniform and the lower side is pressed against the side end regulating plate 104 </ b> R. Then, a resistance force F is generated between the side end regulating plate 104R and the sheet S as shown in FIG. When the resistance force F is generated, the sheet S and the auxiliary tray 101 swing clockwise as indicated by an arrow R. For this reason, when the mounting plate 105 is further raised thereafter, the upper end of the inclined uppermost sheet St comes into contact with the roller 115 at the point P before the pickup roller 102.

  At this time, the roller 115 is urged downward by the pressure spring 116 via the elevating plate 111. For this reason, when the uppermost sheet St abuts on the roller 115, the uppermost sheet St is pressed by the roller 115 above the lower end of the pickup roller 102. When the uppermost sheet St is pressed by the roller 115 in this way, the force of Fr acts on the sheet S and the auxiliary tray 101 at the point P, and the sheet S and the auxiliary tray 101 are moved in the direction opposite to R in the drawing. A moment to swing counterclockwise is generated.

  Here, the point P at which the force Fr acts is a position farther from the pickup roller 102 than the end 115b of the roller 115 on the pickup roller side (sheet feeding means side). Therefore, the distance Xp1 in the width direction between the point P at which the force Fr acts and the swinging fulcrum 101a of the auxiliary tray 101 is greater than the end 115b of the roller 115 on the pickup roller side and the swinging fulcrum 101a of the auxiliary tray 101. Longer than the distance Xp2 in the width direction. Further, the distance Xp2 in the width direction between the end 115b of the roller 115 and the swinging fulcrum 101a of the auxiliary tray 101 is closer to the roller side (pressing means side) of the swinging fulcrum 101a of the auxiliary tray 101 and the pickup roller 102. It is longer than the distance Xp3 in the width direction with the one end 102b.

  On the other hand, when the uppermost sheet St comes into contact with the roller 115, the force Fr applied by the roller 115 is small, but increases as the mounting plate 105 rises. When the force Fr increases, the moment for swinging the auxiliary tray 101 counterclockwise becomes larger than the moment due to the resistance force F, and accordingly, the sheet S and the auxiliary tray 101 swing counterclockwise. The inclination of the uppermost sheet St is corrected.

  Further, when the mounting plate 105 rises, the uppermost sheet St in a state where the upper end is in contact with the roller 115 comes into contact with the one end 102a in the width direction of the pickup roller 102, and thereafter, due to the contact pressure with the pickup roller 102 The auxiliary tray 101 swings. As a result, the uppermost sheet St abuts against the pickup roller 102 evenly as shown in FIG.

  The diameter of the roller 115 is smaller by a predetermined diameter difference Xa than the diameter of the pickup roller 102 as shown in FIG. 6 and the diameter of the idler gear 112 is predetermined with respect to the diameter of the pickup roller 102. It is configured to be reduced by the diameter difference Xb. For this reason, when the uppermost sheet St uniformly contacts the pickup roller 102, the roller 115 and the idler gear 112 do not contact the uppermost sheet St, so that the feeding operation is not affected.

  The roller 115 is provided so as to be removable with respect to the pickup roller support shaft 1021. To replace the pickup roller 102, the roller 115 is removed and then the pickup roller 102 is removed from the shaft.

  As described above, in the present embodiment, when the placement plate 105 is raised, the sheet placed on the auxiliary tray 101 is moved by the roller 115 provided on the side in the width direction of the pickup roller 102. It is designed to be pressed above the lower end. Then, by suppressing the sheet with the rollers 115 in this way, the inclination of the uppermost sheet St can be corrected. As a result, the uppermost sheet St can be made to follow the pickup roller 102 so that a sheet having a non-uniform thickness can be stably fed.

  Heretofore, as shown in FIG. 7, an example of a situation in which contact resistance occurs between the side end regulating plate 104 </ b> R and the sheet S is illustrated, but even if the sheet S is tilted to the opposite side to the left, By the same principle, the uppermost sheet St hits the idler gear 112, and the inclination can be corrected.

  Next, a second embodiment of the present invention will be described. FIG. 9 is a side view showing the configuration of the sheet feeding apparatus according to the present embodiment. In FIG. 9, the same reference numerals as those in FIG. 2 described above indicate the same or corresponding parts.

  In this embodiment, as shown in FIG. 9, the inclination correction of the uppermost sheet St is performed by an inclination correction guide 117 fixed to a frame (not shown) of the printer main body 201 that also serves as the sheet feeding apparatus main body. ing. Here, in this embodiment, the height of the pickup roller 102 at the movable lower limit position is Z0. Further, the height when the paper surface height detection sensor 121 detects the pickup roller 102 pushed up by the rising sheet and is turned on, that is, when the pickup roller 102 is in the standby position, is Z1.

  In addition, the height of the contact surface 117a at the lower end of the inclination correction guide 117 which is an example of the pressing unit and in contact with the uppermost sheet St of the sheet S having a non-uniform thickness is defined as Z2. With respect to the position of the pickup roller 102 and the lower end position of the inclination correction guide 117, the lower end position Z2 of the inclination correction guide 117 is always set to have a relationship of Z2> Z1. This Z2-Z1 corresponds to Xa shown in FIG. 6 of the first embodiment described above. The contact surface 117 a of the inclination correction guide 117 is parallel to the mounting plate 105.

  FIG. 10 is a diagram illustrating a state when a sheet is fed by the sheet feeding apparatus according to the present embodiment, and the uppermost sheet St of the non-uniform thickness sheet S placed on the auxiliary tray 101 is illustrated. A state in which the tilt correction guide 117 is in contact is shown. Here, the inclination correction guide 117 is provided with a gap of Xs on the side of the shaft end which is the other end of the pickup roller support shaft 1021 with one end fixed. In other words, the inclination correction guide 117 is always fixed without being interlocked with the movement of the pickup roller 102.

  In FIG. 10, X0 indicates the distance from the end 117b of the tilt correction guide 117 opposite to the pickup roller 102 to the center of the pickup roller 102 (the swing center of the auxiliary tray 101). X1 is a distance between the inner wall surface 104a facing the sheet of the side end regulating plate 104 and the center position of the pickup roller 102 when a sheet having the longest length in the width direction among the sheets to be placed is set. Is shown. In this embodiment, the distance X0> the distance X1.

  In other words, in the present embodiment, the end 117 b opposite to the pickup roller 102 of the inclination correction guide 117 is positioned on the outer side in the width direction than the inner wall surface 104 a of the side end regulating plate 104. With this configuration, when the sheet S is raised, the sheet can be reliably brought into contact with the inclination correction guide 117.

  Further, as shown in FIG. 10, when the placement plate 105 rises in a state where the sheet S is placed in a state where the height is not uniform and the lower side is in pressure contact with the side end regulating plate 104R, The upper end of the inclined uppermost sheet St contacts the inclination correction guide 117 at point P. At this time, since the inclination correction guide 117 is fixed, when the uppermost sheet St comes into contact with the inclination correction guide 117, a force Fr acts on the sheet S and the auxiliary tray 101 at a point P. As a result, a moment is generated that causes the sheet S and the auxiliary tray 101 to swing counterclockwise in the direction opposite to R in the drawing.

  Here, the point P at which the force Fr acts is a position farther from the pickup roller 102 than the end portion 117c of the tilt correction guide 117 on the pickup roller side (sheet feeding means side). Therefore, the distance Xp1 between the point P at which the force Fr acts and the swinging fulcrum 101a of the auxiliary tray 101 in the width direction is the swinging fulcrum of the end 117c on the pickup roller side of the inclination correction guide 117 and the auxiliary tray 101. It is longer than the distance Xp2 in the width direction with 101a. Further, the distance Xp2 is longer than the distance Xp3 in the width direction between the swing fulcrum 101a of the auxiliary tray 101 and the one end 102b of the inclination correction guide (on the pressing means side) of the pickup roller 102.

  On the other hand, when the uppermost sheet St comes into contact with the roller 115, the force Fr applied by the inclination correction guide 117 is small, but increases as the mounting plate 105 moves up. When the force Fr increases, the moment for swinging the auxiliary tray 101 counterclockwise becomes larger than the moment due to the contact resistance F, and accordingly, the sheet S and the auxiliary tray 101 swing counterclockwise. The inclination of the uppermost sheet St is corrected.

  Further, when the mounting plate 105 is raised, the uppermost sheet St in which the upper end is in contact with the inclination correction guide 117 comes into contact with one end 102a in the width direction of the pickup roller 102, and then comes into contact with the pickup roller 102. The auxiliary tray 101 is swung by the pressure. As a result, the uppermost sheet St abuts against the pickup roller 102 evenly.

  As described above, the lower end position Z2 of the inclination correction guide 117 and the height Z1 of the position of the pickup roller 102 are configured to satisfy the relationship of Z2> Z1. For this reason, when the uppermost sheet St uniformly contacts the pickup roller 102, the inclination correction guide 117 does not contact the uppermost sheet St, so that the feeding operation is not affected. Further, the inclination correction guide 117 is provided so as to be removable or movable with respect to the pickup roller support shaft 1021. When the pickup roller 102 is replaced, the pickup roller 102 is detached from the pickup roller support shaft 1021 after the inclination correction guide 117 is removed or moved from the pickup roller support shaft 1021.

  As described above, in the present embodiment, when the mounting plate 105 is raised, the sheet placed on the auxiliary tray 101 is moved to the lower end of the pickup roller 102 by the inclination correction guide 117 provided on the side of the pickup roller 102. I'm trying to hold it above. Then, by suppressing the sheet in this way, the inclination of the uppermost sheet can be corrected. As a result, the uppermost sheet can be caused to follow the pickup roller 102 so that a sheet having a non-uniform thickness can be stably fed.

  In the above description, the roller 115 or the inclination correction guide 117 is provided on one side in the width direction of the pickup roller 102. However, the present invention is not limited to this. For example, the roller 115 or the inclination correction guide 117 may be provided on the other side in the width direction. Further, the roller 115 may be provided on one side of the pickup roller 102 in the width direction, and the inclination correction guide 117 may be provided on the other side.

DESCRIPTION OF SYMBOLS 10 ... Feeding part, 10a ... Lifting means, 20 ... Image forming part, 100 ... Sheet feeding apparatus, 101 ... Swing mounting part (auxiliary tray), 101a ... Swing fulcrum, 102 ... Sheet feeding means (pickup) Roller), 105 ... Elevating member (mounting plate), 106 ... Paper feed cassette, 106a ... Cassette body, 109 ... Ascending plate, 110 ... Control unit, 111 ... Elevating plate, 115 ... Holding means (roller), 116 ... Addition Pressure spring, 117 ... Pressing means (tilt correction guide), 120 ... cassette attachment / detachment detection sensor, 121 ... paper surface height detection sensor, 200 ... laser printer, 201 ... laser printer body, 1021 ... axis (pickup roller support shaft), M1 ... Lifter drive motor, M2 ... Paper feed motor, S ... Sheet, St ... Top sheet

Claims (11)

An elevating member capable of elevating; and
A swing mounting portion provided on the lifting member so as to be swingable about a swing fulcrum and on which a sheet is mounted;
A sheet feeding means that is provided above the swing placement unit and feeds in contact with a sheet placed on the swing placement unit;
A side end regulating member for regulating a side end position in a width direction orthogonal to the sheet feeding direction of the sheet placed on the swing placement unit;
Raising means for raising the elevating member to a position where the uppermost position of the sheet placed on the swinging placing portion can be fed by the sheet feeding means;
Provided at a side in the width direction of the sheet feeding means, and when the lifting member is raised by the raising means, the sheet is placed at a position where the sheet can be fed to the sheet placed on the swing placement portion. A sheet feeding apparatus comprising: a pressing unit capable of abutting above a lower end of the sheet feeding unit.   The sheet feeding apparatus according to claim 1, wherein a position of the pressing unit that contacts the sheet is higher than a position of the sheet feeding unit that contacts the sheet. The sheet feeding means is located above a swing fulcrum of the swing placement unit,
The distance in the width direction between the end of the pressing means on the sheet feeding means side and the swing fulcrum is longer than the distance in the width direction between the end on the pressing means side of the sheet feeding means and the swinging fulcrum. The sheet feeding apparatus according to claim 1, wherein the sheet feeding apparatus is a sheet feeding apparatus.   When the side end regulating member is in a position for regulating the side end position of the sheet having the longest length in the width direction among the sheets placed on the swinging placement portion, The sheet feeding device according to any one of claims 1 to 3, wherein the sheet feeding device is located above the regulating member. The sheet feeding means is a feeding roller provided on the shaft,
5. The sheet feeding apparatus according to claim 1, wherein the pressing unit is a rotating body that is rotatably provided on a shaft of the feeding roller. 6.   6. The sheet feeding apparatus according to claim 5, wherein the rotating body is detachably provided on a shaft of the feeding roller. One end is supported by the sheet feeding apparatus main body, and includes a shaft that rotatably holds the sheet feeding unit.
4. The sheet feeding device according to claim 1, wherein the pressing unit is disposed at a position that is lateral to the other end of the shaft of the sheet feeding apparatus main body. 5. Feeding device.   8. The sheet feeding apparatus according to claim 7, wherein the pressing unit is provided so as to be removable or movable with respect to the sheet feeding apparatus main body. The sheet is a sheet whose one end side is thicker than the other end side opposite to the one end side,
The sheet feeding apparatus according to claim 1, wherein the pressing unit is provided at a position for pressing one end side of the sheet placed on the swinging placement unit.   The sheet feeding apparatus according to claim 9, wherein the sheet is an envelope.   An image forming apparatus comprising: an image forming unit that forms an image on a sheet; and the sheet feeding device according to any one of claims 1 to 10.

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