JP2007217124A - Sheet feeding device and image reading device and image forming device equipped with it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet feeding device capable of preventing a corner part of a sheet from colliding against an inclined face at first and preventing the corner part from being broken and curved greatly even if the sheet to be fed skews and the corner part hangs down. <P>SOLUTION: The sheet P loaded on a surface S of a lift plate 37 is fed onto the downstream side by a feeding roller 22. Second inclined faces 47, 48 are protrudedly provided on both end sides in the direction of width of passing paper on the downstream side of the lift plate 37 to lift both end sides (corner parts) in the direction of width of passing paper on a tip side of the sheet P. Furthermore, a third inclined face 58 is protrudedly provided on a central side of a first inclined face 53. Since a central side of a tip of the sheet P at feeding time collides against the third inclined face 58 at first and then the lifted corner part collides against the first inclined face, it is possible to prevent the corner part from colliding against the first inclined face 53 at first. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a sheet feeding apparatus that feeds a plurality of sheets stacked on a stacking tray from the uppermost one, and an image reading apparatus and an image forming apparatus including the sheet feeding apparatus. Has a sheet feeding device that prevents sheet conveyance failure caused by the sheet skewing during feeding or the end of the sheet passing width direction hanging down, and the same The present invention relates to an image reading apparatus and an image forming apparatus.

  In sheet feeding devices used in image reading devices and image forming devices (for example, copiers, printers, copiers, and facsimile machines), a plurality of sheets such as originals and recording materials are sequentially ordered from the highest one. There is a known one that feeds downstream (see, for example, Patent Document 1).

  In this case, a plurality of sheets are stacked on the lift plate, the position of the leading edge of the sheet is regulated by a stopper, and the lift plate is raised so that the uppermost sheet is always at a predetermined height. It is arranged at the feeding position. Then, the uppermost sheet is fed by the feeding roller, and the leading edge of the sheet collides with an inclined surface that is continuous with the upper end of the stopper. As a result, the sheet is rolled to prevent rough double feeding.

JP 2002-234622 A

  However, according to Patent Document 1, there is no problem when the sheet fed by the feeding roller collides evenly with the inclined surface, but the sheet is skewed, A problem may occur when the vicinity of both left and right ends (hereinafter referred to as “corners” as appropriate) hangs down. That is, in these cases, the corner portion of the sheet first collides with the inclined surface, and the corner portion is bent or greatly bent, causing subsequent sheet conveyance failure.

  The object of the present invention is that even when the sheet to be fed is skewed or the corners are hanging down, the corners are less likely to collide with the inclined surface first, and the corners are broken, It is an object of the present invention to provide a sheet feeding device which is prevented from being largely bent, and an image reading apparatus and an image forming apparatus provided with the sheet feeding device.

  The invention according to claim 1 relates to a sheet feeding apparatus that feeds a plurality of sheets stacked on a stacking tray in order from the topmost sheet to the downstream side. The sheet feeding apparatus according to the present invention regulates a stopper that regulates a leading end position of the sheets stacked on the stacking tray in a feeding direction, and a side end position of the sheets stacked on the stacking tray in the sheet passing width direction. A side regulating member, a feeding guide having a first inclined surface inclined so that a downstream end is higher than an upstream end disposed in the vicinity of the upper end of the stopper, and sheets stacked on the stacking tray, The lift plate that lifts and lowers at least by supporting the tip side from below, and the tip of the uppermost sheet on the lift plate are set within a height range between the downstream end and the upstream end of the first inclined surface. Lifting means for raising and lowering the lift plate so as to be positioned at a predetermined feeding position, and the uppermost sheet disposed at the feeding position is fed downstream, and the leading edge of the sheet is inclined by the first inclination. A feeding member that abuts against the surface An end guide that protrudes from both ends of the sheet passing width direction on the downstream end side of the lift plate and lifts up both ends of the sheet passing width direction on the leading end side of the sheet on the lift plate. It is said.

  According to a second aspect of the present invention, in the sheet feeding apparatus according to the first aspect, the end guide is inclined such that a protruding height from the lift plate is higher on the downstream end side than on the upstream end side. And having a second inclined surface in contact with the back surface of the sheet on the lift plate.

  The invention according to claim 3 is the sheet feeding apparatus according to claim 2, wherein the protruding height at the downstream end of the second inclined surface is a height between the downstream end and the upstream end of the first inclined surface. It is characterized by being set smaller than the difference of.

  According to a fourth aspect of the present invention, in the sheet feeding apparatus according to the second or third aspect, the second inclined surface is the angle of inclination with respect to the lift plate in a state of being arranged at a position corresponding to the feeding position. It is smaller than the first inclined surface.

  According to a fifth aspect of the present invention, in the sheet feeding apparatus according to the fourth aspect, in the state where the lift plate is disposed at a position corresponding to the feeding position, the second inclined surface is extended to the downstream side. A surface intersects the first inclined surface.

  According to a sixth aspect of the present invention, in the sheet feeding apparatus according to any one of the first to fifth aspects, with respect to the positional relationship in the sheet passing width direction, the end portions of the stopper projecting from both ends of the sheet passing width direction It is arranged between the guides.

  According to a seventh aspect of the present invention, in the sheet feeding device according to the sixth aspect, the feeding guide protrudes at a position corresponding to the stopper along the sheet passing width direction so that the sheet is fed at the time of feeding. It has the 3rd inclined surface by which the paper passing width direction center side is abutted, It is characterized by the above-mentioned.

  The invention according to claim 8 is the sheet feeding apparatus according to claim 7, wherein the third inclined surface is the first inclined surface with respect to the inclination angle with respect to the lift plate in a state of being arranged at a position corresponding to the feeding position. It is characterized by being larger than the inclined surface.

  The invention according to claim 9 is the sheet feeding apparatus according to claim 8, wherein the downstream end of the second inclined surface is more upstream than the upstream end of the third inclined surface with respect to the positional relationship along the sheet feeding direction. By being located on the downstream side, the upstream portion of the third inclined surface and the downstream portion of the second inclined surface are overlapped.

  According to a tenth aspect of the present invention, in the sheet feeding apparatus according to any one of the second to ninth aspects, the feeding roller as the feeding member is located at the center side in the positional relationship along the sheet passing width direction. The stopper and the third inclined surface are disposed on both outer sides of the feeding roller, and the second inclined surface is disposed on both outer sides of the stopper and the third inclined surface, respectively. It is characterized by that.

  The invention according to claim 11 relates to an image reading apparatus comprising a sheet feeding device for feeding a sheet-like document and an image reading means for reading an image of the document fed by the sheet feeding device. is there. The image reading apparatus according to the present invention is characterized in that the sheet feeding apparatus is the sheet feeding apparatus according to any one of claims 1 to 10.

  A twelfth aspect of the present invention relates to an image forming apparatus including a sheet feeding device that feeds a sheet, and an image forming unit that forms an image on the sheet fed by the sheet feeding device. The image forming apparatus according to the present invention is characterized in that the sheet feeding device is the sheet feeding device according to any one of claims 1 to 10.

  According to the first aspect of the present invention, the sheet material stacked on the stacking tray and supported at least at the tip side by the lift plate is regulated by the stopper at the tip position when the lift plate is lifted by the lifting means. The side end position in the paper width direction rises while being regulated by the side regulating member, and the top end of the uppermost one is disposed at a predetermined feeding position within the height range between the downstream end and the upstream end of the first inclined surface. The Therefore, when the sheet at the feeding position is fed downstream by the feeding member, the leading edge of the sheet collides with the first inclined surface. As a result, when the sheets are double-fed at the time of feeding, the sheet is rolled by the shock of the collision and the double feeding is prevented. Further, when the leading edge of the sheet preferably collides with the first inclined surface, a certain amount of skew correction can be performed.

  Here, when the leading edge of the sheet collides with the first inclined surface, the leading edge does not necessarily collide uniformly over the entire width in the sheet passing width direction. For example, when the sheet is skewed at the time of feeding, or when the vicinity of the left and right ends (corners) at the leading edge of the leading edge hangs down compared to the center, the corner of the sheet first collides with the first inclined surface. It will be. Such a phenomenon is likely to occur when, for example, the sheet is thin and has no waist (low rigidity). In this case, the corner of the sheet is bent or greatly curved, which causes subsequent sheet feeding failure.

  Therefore, according to the first aspect of the present invention, the end guides are provided so as to protrude from both ends of the lift plate at the downstream end side in the sheet passing width direction. The corner portion of the sheet is lifted upward by the end guide. Thereby, the sheet | seat attitude | position at the time of feeding can be stabilized by making the corner | angular part side higher than the center side of the front-end | tip of a sheet | seat in advance, and seating a sheet | seat before feeding. Further, considering that the first inclined surface is inclined so that the downstream end is higher than the upstream end, when the corner of the seat is lifted, the corner is not lifted. There is a tendency for the timing of collision with the first inclined surface to be slower than the center side. That is, the corner portion is less likely to collide with the center side first. Even if the corner portion collides with the first inclined surface before the center, the corner portion is lifted upward, so that it collides with the first inclined surface as compared with the case where the corner portion is not lifted. The collision angle at the time of doing will become small, and the shock at the time of a collision will be reduced. For this reason, it can suppress that a corner | angular part bends or curves greatly.

  Thus, according to the first aspect of the invention, before feeding, by lifting both ends (corner portions) in the sheet passing width direction on the leading end side of the sheet, the posture of the sheet at the time of feeding is stabilized, In addition, the timing at which the leading edge of the sheet collides with the first inclined surface is delayed from the center so that the corner is less likely to collide first, so that the shock of the collision can be reduced even if it collides first. As a result, the corners of the sheet can be effectively prevented from being bent or greatly bent.

  According to the second aspect of the present invention, the end guide contacting the back surface of the sheet on the lift plate is inclined in the same direction as the first inclined surface with which the front end of the sheet collides, so that the sheet is fed from the feeding position. Since the corner of the sheet moves almost following the second inclined surface, it is possible to further reduce the shock when the corner collides with the first inclined surface. Further, when the sheet is set on the lift plate, the leading edge of the sheet can be hardly caught by the end portion guide.

  According to the invention of claim 3, the protruding height of the downstream end of the second inclined surface corresponds to the difference between the center of the front end of the sheet disposed at the feeding position and the left and right ends. That this difference is smaller than the difference in height between the downstream end and the upstream end of the first inclined surface means that the center and both ends of the leading edge of the sheet disposed at the feeding position are within the height range of the first inclined surface. It means entering. Therefore, the center and both ends of the front end of the fed sheet can collide with the first inclined surface.

  According to the invention of claim 4, since the inclination angle of the second inclined surface is smaller than the inclination angle of the first inclined surface, the corner portion of the sheet moved along the second inclined surface at the time of feeding can be further ensured. It is possible to cause the first inclined surface to collide with the first inclined surface and reduce the shock at the time of the collision.

  According to the invention of claim 5, since the extended surface extending the second inclined surface to the downstream side intersects the first inclined surface, the corner portion of the sheet moved along the second inclined surface at the time of feeding is provided. Further, it can be made to collide with the first inclined surface even more reliably.

  According to the invention of claim 6, since the stopper is disposed between the end guides along the sheet passing width direction, that is, on the center side, the stopper is not a portion where the corner portion of the sheet is lifted. The center side which is not done will be regulated. Therefore, the leading edge of the sheet can be regulated with high accuracy.

  According to the seventh aspect of the present invention, since the third inclined surface protrudes at a position corresponding to the stopper disposed on the center side, the sheet at the time of feeding first has the third inclined surface on the center side of the tip. It becomes easy to collide with the surface. In other words, the corner of the sheet is less likely to collide with the first inclined surface at the beginning, and the corner is less likely to be bent.

  According to the invention of claim 8, since the third inclined surface has an inclination angle larger than that of the first inclined surface, the corner portion has the first inclined surface after the central side at the leading end of the sheet collides with the third inclined surface during feeding. When colliding with the surface, the timing at which the corner portion of the sheet collides with the first inclined surface is delayed as compared with the case where the inclination angle is the same or the inclination angle of the first inclined surface is larger than that of the third inclined surface. be able to. That is, it becomes difficult for the corner portion to collide before the center side. The same applies to the case where the sheet at the time of feeding is skewed.

  According to the ninth aspect of the present invention, the upstream portion of the third inclined surface and the downstream portion of the second inclined surface are overlapped. The corner portion of the sheet that tends to be formed can be guided by the second inclined surface for a long distance.

  According to the invention of claim 10, the feeding roller is disposed at the center side along the sheet passing width direction, the third inclined surface and the stopper are disposed on both outer sides thereof, and the second inclined surface is disposed on the outer sides thereof. Surface was arranged. According to this, conveying force (feeding force) is applied to the center side of the sheet by the feeding roller, and the leading edge of the sheet collides with the third inclined surfaces on both outer sides, thereby correcting sheet separation and skew feeding. Further, by lifting the corners of the seat by the second inclined surfaces at both ends, it is possible to reduce a shock when the corners collide with the first inclined surface.

  According to the eleventh aspect of the present invention, the effect of the sheet feeding apparatus described above can be achieved as the entire image reading apparatus. That is, for example, in the relationship with claim 1, it is possible to prevent document conveyance failure caused by bending or greatly curving both ends of the leading edge of the document as a sheet. Therefore, it is possible to read a document with high accuracy.

  According to the twelfth aspect of the present invention, the effect of the sheet feeding device described above can be achieved as the entire image forming apparatus. That is, for example, in the relationship with claim 1, it is possible to prevent sheet conveyance failure caused by bending or greatly curving both ends of the leading end of the sheet. Images can be formed.

  Hereinafter, the best embodiment of the present invention will be described in detail with reference to the drawings.

<Embodiment 1>
First, an outline of an image reading apparatus provided with a sheet feeding apparatus according to the present invention will be described, and then the sheet feeding apparatus will be described in detail.

  1 and 2 show an image reading apparatus 10 according to the present invention. In the following description, the direction of arrow A in FIGS. 1 and 2 is referred to as the sheet feeding direction or the downstream side, and the direction of arrow B is referred to as the upstream side. Further, the direction of arrow CD in FIG. 1 is referred to as the paper width direction (left-right direction), and the direction of arrow C is left and the direction of arrow D is right. 1 and 2, FIG. 1 is a diagram showing an overview of the image reading apparatus 10 as a whole, and is a perspective view of the image reading apparatus 10 as viewed from the upper left side obliquely upward. FIG. 2 is a schematic view of a vertical cross section along the sheet feeding direction of the image reading apparatus 10 as viewed from the left.

  As shown in FIGS. 1 and 2, the image reading device 10 conveys a sheet feeding device 11 that feeds a sheet (original) P with an image attached thereto, and a sheet fed by the sheet feeding device 11. A sheet conveying device 12 that performs image reading, an image reading unit 13 that reads an image of the sheet P conveyed by the sheet conveying device 12, and a discharge tray 14 that discharges the sheet P after image reading.

  Among these, the sheet feeding apparatus 11 includes a stacking tray 21 on which a plurality of sheets P are stacked in a stacked state. The plurality of sheets P are placed on the stacking tray 21 with their image surfaces facing upward. As will be described later, the plurality of sheets P on the stacking tray 21 are sequentially arranged at a predetermined feeding position from the uppermost sheet P (the uppermost sheet P), and are fed as feeding members. The roller 22 is fed downstream from the feeding position by the rotation in the direction of arrow E. The sheet feeding apparatus 11 will be described in detail later.

  The sheet conveying device 12 includes a conveying belt 23 and a retard roller 24 disposed immediately downstream of the above-described feeding roller 22. The conveyor belt 23 is stretched between a driving roller 25 and a driven roller 26, and is rotated in the direction of arrow F (sheet feeding direction) by the driving roller 25. On the other hand, the retard roller 24 is rotated in the arrow G direction (sheet return direction). When only one sheet P is fed from the sheet feeding device 11 by the feeding roller 22, the sheet P is further conveyed downstream by the conveying belt 23. On the other hand, when a plurality of sheets P are overlapped and overlapped, only the uppermost sheet P (first sheet P) is conveyed downstream by the conveying belt 23. At the same time, conveyance of the next and subsequent sheets P (second and subsequent sheets P) is stopped by the retard roller 24 and stopped. The first sheet P conveyed to the downstream side has its leading end collided with the nip of the stopped pair of registration rollers 27 to correct skew, and further downstream by rotation of the registration rollers 27 thereafter. Conveyed to the side. The sheet P conveyed downstream is conveyed to the image reading position R by the large-diameter common roller 28 and the small-diameter conveying rollers 30, 31, 32, and further from the image reading position to the conveying roller 33 and the conveying roller pair 34. And is discharged onto the discharge tray 14 by the discharge roller pair 35.

  The image reading unit 13 is configured by, for example, a contact image sensor disposed at the image reading position R described above. The image reading unit 13 sequentially reads the images of the sheets P conveyed by the sheet conveying apparatus 12 at the image reading position R. The read image is sent as image information to an image forming apparatus such as a copying machine, a printer, or a facsimile. In copying machines and printers, an image is formed on a recording material (recording medium) such as paper on the basis of this image information, and image information is transmitted in a facsimile.

  The discharge tray 14 is disposed below the sheet feeding device 11 described above. The sheet P after the image reading is discharged and stacked on the discharge tray 14 with the image roller faced down by the discharge roller pair 35 of the sheet conveying device 12 described above.

  In the image reading apparatus 10 having the above-described configuration, the plurality of sheets P set on the stacking tray 21 are sequentially fed from the feeding position to the downstream side by the feeding roller 22 from the feeding position, and are fed. While the sheet P is conveyed by the sheet conveying device 12, the image on the sheet is read by the image reading unit 13 at the image reading position R, and the sheet P after the image reading is discharged onto the discharge tray 14. This is the end of the general description of the image reading apparatus 10.

  The sheet feeding apparatus 11 according to the present invention can be used in the above-described image reading apparatus 10 given as an example.

  The sheet feeding apparatus 11 will be described in detail with reference to FIGS. 3, 4, 5, and 6, and appropriately using FIGS. 1 and 2. Among these, FIG. 3 is a perspective view of the vicinity of the downstream end of the sheet feeding device 11 as viewed from the diagonally upper left side of the sheet feeding device 11. FIG. 4 is a view of the longitudinal section in a state in which the lift plate 37 (described later) is disposed at the lowermost lower position, and FIG. 5 is a view of the lift plate 37 at the uppermost upper position. It is the figure which looked at the arranged state longitudinal section from the left. FIG. 6 is a schematic enlarged view of a part of FIG. 4 and FIG. 5 are partially different in the illustrated configuration because the positions of the cross sections are different.

  As shown in FIGS. 1 and 2, the sheet feeding device 11 includes a stacking tray 21 on which a plurality of sheets P are stacked. In the stacking tray 21, the left side portion on the upstream side is an auxiliary tray 36 that can enter and exit in the left-right direction with respect to the right side portion. The auxiliary tray 36 is appropriately moved in and out according to the size of the sheets P stacked on the stacking tray 21.

  As shown in FIGS. 1, 2, and 3, on the downstream side of the stacking tray 21, there is disposed a lift plate 3737 that lifts and lowers the sheet P stacked on the stacking tray 21 while supporting at least the front end side from below. It is installed. The lift plate 37 is formed in a rectangular shape that is long in the left-right direction, and the width in the left-right direction is set slightly shorter than the width in the left-right direction of the stacking tray 21. The lift plate 37 is supported by the stacking tray 21 so as to be able to swing substantially in the vertical direction with respect to the swing center 38 on the upstream end side. The lift plate 37 is moved up and down substantially in the up and down direction by a swinging operation, with the downstream end side ascending / descending between the lower limit shown in FIG. 4 and the upper limit shown in FIG. The lowering limit described above corresponds to the retreat position of the lift plate 37 when setting the sheet P on the stacking tray 21, and the rising limit is immediately after the last sheet P on the stacking tray 21 is fed. It corresponds to the position. A left side restricting member 40 and a right restricting member 41 are erected on the upper surface of the lift plate 37 near the left end and the right end, respectively. Guide grooves 42 are formed on the upper surface of the lift plate 37 in the left-right direction, and the left and right side regulating members 40 and 41 are guided by the guide grooves 42 and moved on the surface of the lift plate 37 in the left-right direction. can do. The left and right side regulating members 40 and 41 are linked to each other by, for example, a rack and pinion mechanism, and when one is moved inward, the other is also moved inward, and conversely, when one is moved outward, the other is Also move to the outside. That is, in the present embodiment, the sheet P placed on the surface of the stacking tray 21 is center-referenced (in the sheet passing width direction) with its left and right ends regulated by the left and right side regulating members 40 and 41. The sheet is fed by a feeding roller 22 which will be described later. These side restricting members 40 and 41 move up and down as the lift plate 37 moves up and down. Further, as shown in FIG. 3, auxiliary side regulating members 43 and 44 project from left and right ends on the downstream end side of the lift plate 37, respectively. The auxiliary side restricting members 43 and 44 are fixedly arranged unlike the side restricting members 40 and 41 that are movable in the left-right direction.

  As shown in FIG. 3, recesses 45, 46 are formed at positions corresponding to stoppers 54, 55, which will be described later, on the center side in the left-right direction at the downstream end of the lift plate 37. Second inclined surfaces 47 and 48 as end guides project between 46 and the auxiliary side regulating members 43 and 44. The end guides 47 and 48 will be described in detail later.

  As shown in FIGS. 3 and 6, a stopper surface 51 in the substantially vertical direction is formed on the immediately downstream side of the lift plate 37 so as to correspond to the tip edge 50 of the lift plate 37. A first inclined surface 53 of the feeding guide 52 is formed so as to be continuous with the upper end of the surface 51. The stopper surface 51 and the first inclined surface 53 are set to be longer than the left-right width of the lift plate 37, that is, longer than the sheet passing width (width in the left-right direction) of the sheet P placed on the lift plate 37. . Stoppers 54 and 55 are provided on the center side of the stopper surface 51. In the present embodiment, the stoppers 54 and 55 are formed in a plate shape that is long in the vertical direction, and are disposed so as to protrude on the stopper surface 51. On the other hand, the first inclined surface 53 is formed by a plane inclined such that the downstream end 57 is higher than the upstream end 56 that coincides with the upper end of the stopper surface 51 described above. A third inclined surface 58 protrudes from the first inclined surface 53 at a position corresponding to the above-described stoppers 54 and 55 on the center side in the sheet passing width direction. The feeding guide 52 described above includes the first inclined surface 53 and the third inclined surface 58 described above. As shown in FIG. 6, the inclination angle of the first inclined surface 53 with respect to the upper surface S of the lift plate 37 placed at the upper limit is α, the inclination angles of the second inclined surfaces 47 and 48 are β, and the third inclined surface. If the inclination angle is γ, β <α <γ is set. The reason will be described later.

  The above-described stoppers 54 and 55 regulate the position of the front end of the sheet P when the sheet P as a document is set on the stacking tray 21 and when the front end side of the sheet P is raised by the lift plate 37. is there. Further, as will be described later, the third inclined surface 58 is in contact with the center side at the leading edge of the sheet P during feeding, while the first inclined surface 53 is in contact with the corner portion of the sheet P during feeding. It is what is done.

  As schematically shown in FIG. 6, the elevating means 60 includes an elevating mechanism 61 for elevating and lowering the lift plate 37, a motor 62 for driving the elevating mechanism 61, and the lift plate 37 in a state arranged at the upper limit. The detection sensor 63 is arranged near the tip of the sensor, and a control device 64 that controls the motor 62 based on the output of the detection sensor 63. Here, as the elevating mechanism 6, for example, a mechanism using an eccentric cam can be used. In the detection sensor 63 described above, the uppermost sheet P on the lift plate 37 is raised to a predetermined feeding position when the sheet P stacked on the lift plate 37 is lifted by the lift mechanism 37 by the lifting mechanism 61. Sometimes, the sheet P is detected, and the control device 64 stops the motor based on the detection signal. Here, the feeding position is a predetermined position set in a height range between the downstream end 57 and the upstream end 56 of the first inclined surface, and the leading end of the uppermost sheet P has a leading end. When this feed position is reached, the feed roller 22 feeds downstream. In the present embodiment, the detection sensor 63 detects the vicinity of the leading end that can be placed in the center of the uppermost sheet P in the sheet passing width direction, and each time the uppermost sheet P is fed, the next uppermost sheet P is detected. The position of the sheet P is detected. As the entire lifting means 60, the uppermost sheet P fed by the feeding roller 22 is always located at the feeding position.

  The uppermost sheet P arranged at the feeding position is conveyed downstream by a feeding roller 22 as a feeding member. The feeding roller 22 is disposed at the center in the sheet passing width direction on the leading end side of the lift plate 37. This position corresponds to the arrangement position of the retard roller 24 described above. The uppermost sheet P placed at the feeding position by the above-described lifting means 60 is brought into contact with the feeding roller 22. Then, when the feeding roller 22 rotates in the direction of arrow E in FIG. 2, the uppermost sheet P is fed toward the downstream side.

  Next, the above-described second inclined surface will be described in detail. As shown in FIG. 6, the second inclined surfaces 47 and 48 are formed in a planar shape inclined such that the protruding height from the surface S of the lift plate 37 is higher on the downstream side than on the upstream side. Then, it contacts the back surface in the vicinity of the left and right end portions on the front end side of the sheet P placed on the front surface S of the lift plate 37.

Further, in the present embodiment, the second inclined surfaces 47 and 48 have the following characteristics.
(1) As shown in FIG. 6, the protrusion height H (for example, about 2 mm) at the downstream end of the second inclined surfaces 47 and 48 with respect to the surface S of the lift plate 37 is the first inclined surface 53. Is set smaller than the difference in height between the downstream end 57 and the upstream end 56.
(2) The inclination angle α of the second inclined surface 53 and the inclination angles of the second inclined surfaces 47 and 48 with respect to the surface S of the lift plate 37 (see FIG. 6) in a state arranged at the position corresponding to the feeding position. As described above, the relationship between β and the inclination angle γ of the third inclined surface 58 is β <α <γ.
(3) In a state where the lift plate 37 is disposed at a position corresponding to the feeding position, an extended surface (a two-dot chain line L in FIG. 6) obtained by extending the second inclined surface to the downstream side is the first inclined surface 53. Intersect.
(4) Regarding the positional relationship along the sheet feeding direction, the downstream end 65 of the second inclined surfaces 47 and 48 is located on the downstream side of the upstream end 66 of the third inclined surface 58, so that the third inclined surface The upstream portion of 58 and the downstream portion of the second inclined surfaces 47 and 48 overlap.

  The sheet feeding device 11 configured as described above has the following operations and effects.

  By lifting the corner on the leading end side of the sheet P on the lift plate 37 with the end guide, the timing at which the corner of the sheet P hits the first inclined surface 53 at the time of feeding can be delayed. In addition, the corner portion is less likely to strike first, and the corner portion can be prevented from being bent or bent. Moreover, since the angle at the time of a corner | angular part colliding can be made shallow (small), the shock at the time of a collision can be relieve | moderated and a corner | angular part bending etc. can be prevented.

  Further, by inclining the second inclined surfaces 47 and 48 as end guides in the same direction as the first inclined surface 57, it is possible to further reduce the shock when the corner portion collides with the first inclined surface 53. It is.

  Further, by adopting the configuration as described in (1) above, the central side at the leading end of the fed sheet P is collided with the third inclined surface 58, and the corner is collided with the first inclined surface 53, Separation of the sheet P can be performed satisfactorily.

  Further, by adopting the configuration as described in (2) above, the corner portion of the leading end of the sheet P at the time of feeding first moves following the second inclined surfaces 47 and 48 having a small inclination angle, and thereafter, Since it collides with the 1st inclined surface 53 with a larger inclination | tilt angle than that, the shock at the time of a collision can be reduced further. Further, since the inclination angle γ of the third inclined surface is larger than the inclination angle α of the first inclined surface 53, the angle of the sheet P with respect to the timing at which the center side of the leading end of the sheet P collides with the third inclined surface 58. The timing at which the part collides with the first inclined surface 53 can be delayed.

  Furthermore, with the configuration as described in (3) above, the corner portion of the sheet P can be made to collide with the first inclined surface 53 even more reliably.

  Further, by adopting the configuration as described in (4) above, the corners of the sheet P, which tends to be unstable during feeding, are longer by the second inclined surfaces 47 and 48 than when there is no overlap. The distance can be guided to stabilize the feeding posture.

  Note that the characteristic configuration of the present invention protrudes from both ends in the sheet passing width direction on the downstream end side of the lift plate 37 and lifts both ends in the sheet passing width direction on the leading end side of the sheet P on the lift plate 37 upward. An end guide is provided.

  Therefore, the end guide is configured by the second inclined surfaces 47 and 48, or the second inclined surfaces 47 and 48 are configured such that the projecting height is higher at the downstream end than at the upstream end. In addition, the addition of the above-described configurations (1) to (4) can be appropriately selected or combined.

  In the above description, the conveyance guide 52 has been described by way of example in which the first inclined surface 53 and the third inclined surface 58 projecting from the first inclined surface 53 have been described. The present invention can also be applied to the case where the third inclined surface 58 is not provided, and in this case, the same effect can be obtained.

  In the above embodiment, the case where the sheet feeding apparatus 11 according to the present invention is used in an image reading apparatus has been described as an example. However, the sheet feeding apparatus 11 according to the present invention is not limited to this. For example, in an image forming apparatus such as a copying machine, a printer, or a facsimile, the sheet P can be used as a sheet feeding apparatus that feeds the sheet P to the image forming unit. In this case, since the conveyance failure of the sheet P due to the corner portion of the sheet P being bent or greatly curved can be prevented, an image defect caused by the conveyance failure, for example, the folded sheet P Thus, it is possible to form an image and prevent image defects such as image displacement with respect to the sheet P to form a high-quality image.

  In the above description, the case where the sheet feeding apparatus of the present invention is applied to an image reading apparatus has been mainly described as an example. However, the present invention is not limited to an image reading apparatus, for example, a copying machine, a printer, a facsimile machine, and the like. Also in an image forming apparatus such as a multifunction machine, the present invention can be widely applied as a sheet feeding apparatus for feeding a sheet to be an image forming target.

FIG. 2 is a diagram showing an overview of the entire image reading apparatus, and is a perspective view of the image reading apparatus as viewed from the upper left side obliquely upward. FIG. 5 is a schematic diagram of a longitudinal section taken along the sheet feeding direction of the image reading apparatus as viewed from the left. FIG. 6 is a perspective view of the vicinity of the downstream end of the sheet feeding device as viewed obliquely from the upper left of the sheet feeding device. It is the figure which looked at the state by which the lift board was arrange | positioned in the lowest downward position from the left. It is the figure which looked at the state by which the lift board was arrange | positioned in the uppermost raise position from the left. It is the schematic diagram which expanded a part in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Image reading apparatus, 11 ... Sheet feeding apparatus, 13 ... Image reading means, 21 ... Loading tray, 22 ... Feeding roller (feeding member), 37 ... Lift plate, 40, 41 ... ... side regulating member, 47, 48 ... second inclined surface (end guide), 52 ... feeding guide, 53 ... first inclined surface, 54, 55 ... stopper, 56 ... first inclined surface Upstream end, 57 ... downstream end of the first inclined surface, 58 ... third inclined surface, 60 ... elevating means, P ... sheet (original), 65 ... downstream end of the second inclined surface, H ... Projection height of the second inclined surface, L: Extension surface, α: Inclination angle of the first inclined surface, β: Inclination angle of the second inclined surface, γ: Inclination angle of the third inclined surface

Claims (12)

Among a plurality of sheets stacked in a stacked state on a stacking tray, in a sheet feeding device that feeds downstream from the topmost sheet in order,
A stopper for regulating the leading end position in the feeding direction of the sheets stacked on the stacking tray;
A side regulating member that regulates a side end position in the sheet passing width direction of the sheets stacked on the stacking tray;
A feeding guide having a first inclined surface inclined such that the downstream end is higher than the upstream end disposed in the vicinity of the upper end of the stopper;
A lift plate that supports and lifts at least the front end side of the sheets stacked on the stacking tray from below;
The lift plate is positioned so that the leading edge of the uppermost sheet on the lift plate is located at a predetermined feeding position set within a height range between the downstream end and the upstream end of the first inclined surface. Elevating means for elevating and lowering,
A feeding member that feeds the uppermost sheet disposed at the feeding position downstream and abuts the leading edge of the sheet against the first inclined surface;
An end guide that protrudes at both ends in the sheet passing width direction on the downstream end side of the lift plate and lifts up both ends in the sheet passing width direction on the leading end side of the sheet on the lift plate,
A sheet feeding apparatus characterized by that. The end guide has a second inclined surface that is inclined so that a protruding height from the lift plate is higher on the downstream end side than on the upstream end side, and is in contact with the back surface of the sheet on the lift plate. ,
The sheet feeding apparatus according to claim 1. The protruding height at the downstream end of the second inclined surface is set to be smaller than the difference in height between the downstream end and the upstream end of the first inclined surface.
The sheet feeding apparatus according to claim 2, wherein the sheet feeding apparatus is a sheet feeding apparatus. The second inclined surface is smaller than the first inclined surface with respect to the inclination angle with respect to the lift plate in a state of being arranged at a position corresponding to the feeding position.
The sheet feeding apparatus according to claim 2, wherein the sheet feeding apparatus is a sheet feeding apparatus. In the state where the lift plate is arranged at a position corresponding to the feeding position, an extended surface extending the second inclined surface downstream intersects the first inclined surface.
The sheet feeding apparatus according to claim 4, wherein the sheet feeding apparatus is a sheet feeding apparatus. With respect to the positional relationship in the sheet passing width direction, the stopper is disposed between end guides protruding on both ends of the sheet passing width direction.
The sheet feeding apparatus according to claim 1, wherein the sheet feeding apparatus is a sheet feeding apparatus. The feeding guide has a third inclined surface that protrudes at a position corresponding to the stopper along the sheet passing width direction and that abuts on the center side in the sheet passing width direction of the sheet during feeding.
The sheet feeding apparatus according to claim 6. Regarding the inclination angle with respect to the lift plate in the state of being arranged at a position corresponding to the feeding position, the third inclined surface is larger than the first inclined surface,
The sheet feeding apparatus according to claim 7, wherein the sheet feeding apparatus is a sheet feeding apparatus. With respect to the positional relationship along the sheet feeding direction, the downstream end of the second inclined surface is located downstream of the upstream end of the third inclined surface, so that the upstream portion of the third inclined surface The downstream portion of the second inclined surface overlaps,
The sheet feeding apparatus according to claim 8, wherein the sheet feeding apparatus is a sheet feeding apparatus. Regarding the positional relationship along the sheet passing width direction, a feeding roller as the feeding member is disposed on the center side, and the stopper and the third inclined surface are disposed on both outer sides of the feeding roller, The second inclined surfaces are disposed on both outer sides of the stoppers and the third inclined surfaces, respectively.
The sheet feeding apparatus according to claim 2, wherein the sheet feeding apparatus is a sheet feeding apparatus. An image reading apparatus comprising: a sheet feeding device that feeds a sheet-like document; and an image reading unit that reads an image of the document fed by the sheet feeding device.
The sheet feeding device is the sheet feeding device according to any one of claims 1 to 10,
An image reading apparatus. In an image forming apparatus comprising: a sheet feeding device that feeds a sheet; and an image forming unit that forms an image on the sheet fed by the sheet feeding device;
The sheet feeding device is the sheet feeding device according to any one of claims 1 to 10,
An image forming apparatus.

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