JP5991583B2 - Sheet conveying apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to a sheet conveying apparatus used in an image forming apparatus such as a printer, a facsimile, a copying machine, and the like, and an image forming apparatus including the sheet conveying apparatus.

  As a method for separating and transporting stacked sheets such as originals and recording paper, an electrostatic adsorption separation method has been proposed in which an electric field is formed on an adsorption belt and the sheet is adsorbed and separated by contacting the sheet.

  An electrostatic adsorption separation type sheet conveying apparatus described in Patent Document 1 includes a dielectric adsorption belt wound around two stretching rollers, charge applying means for applying alternating charges to the adsorption belt, and these The adsorption separation unit comprised with the holder which hold | maintains. The holder rotatably supports the two stretching rollers, and is fixed to a rotation shaft provided upstream of the two stretching rollers in the sheet conveying direction. Further, a swinging means for swinging the suction separation unit with the rotation shaft as a fulcrum is provided so that the suction belt reciprocates between the suction position and the transport position. The suction position is a position where the uppermost sheet of the sheet bundle stacked on the bottom plate of the paper tray is brought into contact with the suction belt and sucked. The transport position is a position for transporting the uppermost sheet that is further away from the sheet bundle than the suction position and sucked by the suction belt.

  In addition, it has one pressing roller that is provided inside the suction belt and presses the suction belt toward the sheet bundle, and by pressing the suction belt with the pressing roller, the suction belt is pressed against the uppermost sheet, The contact between the suction belt and the uppermost sheet is ensured.

  The electrostatic attraction force generated between the adsorption belt and the uppermost sheet increases as the distance between the two becomes shorter. For this reason, the suction belt and the uppermost sheet are prevented from generating a gap between the suction belt and the uppermost sheet due to waviness of the suction belt or the sheet so that sufficient electrostatic attraction force can be obtained so as not to cause a suction failure. It is desirable to contact the sheet.

  However, the pressing area of the suction belt by one pressing roller is small with respect to the belt stretching region by two stretching rollers. Therefore, the further away from the pressing roller in the sheet conveying direction, the smaller the pressing force applied to the suction belt from the pressing roller, and the suction belt cannot be pressed against the uppermost sheet. The problem of being unable to do so occurs.

  The present invention has been made in view of the above problems, and an object thereof is to provide a sheet conveying apparatus capable of enhancing the adsorption property between the adsorption belt and the sheet, and an image forming apparatus including the sheet conveying apparatus. It is to be.

In order to achieve the above object, the invention of claim 1 includes an endless suction belt disposed opposite to an upper surface of a stacked sheet bundle, a first tension roller that stretches the suction belt, and a first tension roller. A suction separation unit having a second stretching roller located upstream of the first stretching roller in the sheet conveying direction; a charging means for charging the surface of the suction belt; and the uppermost sheet of the sheet bundle as the suction belt. The suction belt and the sheet bundle are brought into contact with each other between a suction position to be sucked and a spaced position where the uppermost sheet sucked by the suction belt is transported and separated from the sheet bundle than the suction position. In the sheet conveying apparatus provided with the contacting / separating means for separating, a plurality of pressing members for pressing the suction belt toward the sheet bundle are provided along the sheet conveying direction inside the suction belt , the above A suction separation unit swinging means for swinging the suction separation unit between the suction position and the separation position around a swinging fulcrum provided on the upstream side in the sheet conveying direction from the two stretching rollers; Each pressing member is configured to press the suction belt with different pressing forces, and the pressing member located on the upstream side in the sheet conveying direction has a higher pressing force .

  In the present invention, since a plurality of pressing members are provided inside the suction belt along the sheet conveying direction, the pressing area of the suction belt by each pressing member in the sheet conveying direction is larger than when only one pressing member is provided. can do. As a result, the contact area between the suction belt and the uppermost sheet in the sheet conveying direction can be ensured as compared with the case where only one pressing member is provided, and therefore the adsorbability between the suction belt and the uppermost sheet can be increased accordingly. .

  As mentioned above, according to this invention, there exists the outstanding effect that the adsorptivity of an adsorption | suction belt and a sheet | seat can be improved.

(A) The schematic diagram which shows the state which an adsorption separation unit is located in an adsorption position, (b) The schematic diagram at the time of seeing the one end side of the sheet width direction orthogonal to the sheet conveyance direction of an adsorption separation unit from upper direction. 1 is a schematic diagram showing a copying machine according to an embodiment. The perspective view which shows schematic structure of a paper feed part. FIG. 3 is a schematic diagram illustrating a sheet feeding unit. The figure which shows the principal part structure of an adsorption | suction separation unit. The exploded view of a housing. The schematic block diagram of the drive mechanism which rotationally drives an adsorption belt. The perspective view which shows the principal part structure of an adsorption | suction separation unit. The perspective view which shows the modification of an adsorption | suction separation unit. FIG. 6 is a diagram illustrating a sheet conveying operation using the sheet conveying apparatus. The figure explaining the relationship between the gravity center of the adsorption | suction separation unit, and the meshing position of a rocking | fluctuation mechanism. The figure explaining the structure which provided the rack and pinion mechanism only in the belt width direction one end side. FIG. 10 is a schematic configuration diagram of a sheet conveying apparatus according to a first modification. FIG. 6 is a schematic configuration diagram of a drive mechanism and a swing mechanism of the sheet conveying apparatus according to the first modification. FIG. 10 is a schematic configuration diagram of a sheet conveying apparatus according to a second modification. FIG. 10 is a schematic configuration diagram of a swing mechanism of a sheet conveying device according to the second modification. FIG. 10 is a schematic configuration diagram of a sheet conveying apparatus according to a third modification. FIG. 10 is a diagram illustrating another example of the swing mechanism of the sheet conveying device according to the third modification. The figure explaining the various structures of a press member, and the assembly | attachment to a bracket. The figure which looked at the adsorption separation unit at the time of providing a compression spring in the position of a bracket from the upper part. The figure which looked at the adsorption | suction isolation | separation unit at the time of providing a compression spring inside the adsorption | suction belt inside a sheet | seat width direction rather than a bracket from upper direction. The figure explaining operation | movement of an adsorption | suction separation unit from the time of adsorption | suction to the time of conveyance. The schematic diagram at the time of paying attention to a housing, omitting illustration of a pressing member, a compression spring, etc. with an adsorption separation unit. The schematic diagram at the time of paying attention to a press member and a compression spring, omitting illustration of an upstream tension roller, a housing, and an adsorption belt in an adsorption separation unit. (A) Schematic diagram showing a state where the suction separation unit is located at the suction position when using thin paper, (b) The suction separation unit when using thin paper swings from the suction position toward the transport position. The schematic diagram which shows a state when it is. (A) Schematic diagram showing a state where the adsorption separation unit is located at the adsorption position when using thick paper, (b) The adsorption separation unit when using the thick paper swings from the adsorption position toward the conveyance position. The schematic diagram which shows a state when it is. The schematic diagram at the time of making the curvature of the contact surface of the pressing member 35B smaller than the curvature of the contact surface of the pressing member 35A. FIG. 4 is a schematic diagram illustrating a copying machine according to a second embodiment. FIG. 3 is a perspective view illustrating a schematic configuration of a paper feeding unit in the copying machine. FIG. 3 is a schematic diagram illustrating a basic configuration of a sheet conveying device provided in a sheet feeding unit. The figure explaining the separation and conveyance of the sheet by the sheet conveying apparatus. The figure which shows embodiment of the adsorption | suction separation unit which eliminated the spring which urges | biases a downstream tension roller to the sheet bundle side. The figure which shows embodiment of the adsorption separation unit which made the long hole circular arc shape. The figure which shows embodiment of the adsorption separation unit which inclined the long hole. The figure which shows embodiment which extended the long hole when the adsorption | suction separation unit exists in the adsorption | suction position to the orthogonal | vertical direction with respect to the sheet | seat surface of a sheet bundle.

  Hereinafter, an embodiment in which the present invention is applied to a copying machine which is an electrophotographic image forming apparatus will be described. Needless to say, the present invention can be applied not only to the image forming apparatus of the present embodiment but also to, for example, an inkjet image forming apparatus.

FIG. 2 is a schematic diagram illustrating the copying machine 100 according to the present embodiment.
The copying machine 100 includes an automatic document feeder 59, a document reading unit 58, an image forming unit 50, a paper feeding unit 52, and the like. The automatic document feeder 59 separates documents one by one from a bundle of documents placed on the document tray 59a and automatically feeds them to a contact glass on the document reading unit 58. The document reading unit 58 reads the document conveyed on the contact glass by the automatic document conveying device 59. The image forming unit 50 is an image forming unit that forms an image on a sheet that is a recording material fed from the paper feeding unit 52 based on a document image read by the document reading unit 58. The sheet feeding unit 52 accommodates the sheet bundle 1 in which a plurality of sheets are stacked, and feeds the uppermost sheet 1 a located at the uppermost position from the sheet bundle 1 to the image forming unit 50.

  The image forming unit 50 includes a charging device 62, a developing device 64, a transfer device 54, a photoconductor cleaning device 65, and the like around a photoconductor 61 as a latent image carrier. The image forming unit 50 also includes an optical writing unit (not shown) for irradiating the photoreceptor 61 with a laser beam 63, a fixing device 55 for fixing the toner image on the sheet, and the like.

  In the image forming unit 50 configured as described above, as the photosensitive member 61 rotates, the surface of the photosensitive member 61 is first uniformly charged by the charging device 62. Next, a laser beam 63 from an optical writing unit (not shown) based on image data input from a personal computer, a word processor, or the like, or image data of a document read by the document reading unit 58 is irradiated onto the photoreceptor 61. An electrostatic latent image is formed. Thereafter, a toner image is formed on the photosensitive member 61 by attaching toner with the developing device 64 to visualize the electrostatic latent image.

  On the other hand, the sheet feeding unit 52 separates and conveys the sheets one by one, and stops against the registration roller 53. Then, in synchronization with the toner image formation timing of the image forming unit 50, the sheet that has been pressed against the registration roller 53 and stopped is sent to the transfer unit where the photoconductor 61 and the transfer device 54 face each other. In the transfer unit, the toner image on the photoreceptor 61 is transferred to the supplied sheet. The sheet onto which the toner image has been transferred is fixed to the toner image by the fixing device 55 and then discharged to the paper discharge tray 57 by the paper discharge roller pair 56. On the other hand, the surface of the photoconductor 61 after the toner image transfer is cleaned by removing residual toner with the photoconductor cleaning device 65 to prepare for image formation again.

  3 is a perspective view illustrating a schematic configuration of the paper feeding unit 52, FIG. 4 is a schematic diagram illustrating the paper feeding unit 52, and FIG. 5 is a diagram illustrating a main configuration of the adsorption separation unit 110. .

  The paper feeding unit 52 is a sheet feeding cassette 11 serving as a sheet material accommodation unit that stacks and accommodates a plurality of sheets, and a sheet bundle 1 composed of a plurality of sheets on the paper feeding cassette 11 and located at the uppermost position. And a sheet conveying device 200 that separates and conveys the upper sheet 1a.

  As shown in FIG. 4, the paper feed cassette 11 has a bottom plate 7 on which a plurality of stacked sheet bundles 1 are stacked. A support member 8 that supports the bottom plate 7 is rotatably mounted between the bottom portion of the paper feed cassette 11 and the bottom plate 7. As shown in FIG. 3, the sheet feeding unit 52 is provided with a sheet detection unit 40 that detects that the uppermost sheet 1 a of the sheet bundle 1 has reached a predetermined position.

  The sheet detection means 40 includes a filler 44 that is rotatably supported by a shaft 42 provided in the apparatus main body, and a transmission optical sensor 43. When the support member 8 is rotated by a drive motor (not shown) to raise the bottom plate 7, the sheet bundle 1 stacked on the bottom plate 7 rises and the uppermost sheet 1 a comes into contact with the filler 44. At this time, the light receiving unit 43a of the transmissive optical sensor 43 receives light from the light emitting unit 43b. Further, when the bottom plate 7 is raised, the filler 44 blocks the light from the light emitting portion 43b, and the light receiving portion 43a does not receive the light. Thereby, it is detected that the uppermost sheet 1a of the sheet bundle 1 has reached a predetermined position, and the rotation of the support member 8 is stopped.

  The sheet conveying apparatus 200 includes an adsorption / separation unit 110, an oscillation mechanism 120 that is an oscillation unit for oscillating the adsorption / separation unit 110, a drive mechanism 130 that moves the adsorption belt 2 endlessly, and the like. As shown in FIG. 5, the adsorption separation unit 110 includes an adsorption belt 2 that is stretched between a downstream tension roller 5 and an upstream tension roller 6.

The adsorption belt 2 has a surface layer made of polyethylene terephthalate with a thickness of about 50 [μm] having a resistance of 10 ⁸ [Ω · cm] or more, and a resistance of 10 ⁶ [Ω · cm] or less formed by aluminum vapor deposition. It has a two-layer structure having a conductive layer. By making the suction belt 2 have the two-layer structure as described above, the conductive layer can be used as a grounded counter electrode, and the charging member 3 serving as a charging means for applying a charge to the suction belt 2 is used as the suction belt 2. It can be provided anywhere as long as it is in contact with the surface layer. Further, a rib 23 for stopper is provided on the inner side of both edges in the width direction of the suction belt 2, and the ribs 23 are connected to both end surfaces of the downstream tension roller 5 and the upstream tension roller 6. This prevents the suction belt 2 from being displaced.

The downstream tension roller 5 is provided with a conductive rubber layer having a resistance value of 10 ⁶ [Ω · cm] on the surface, and the upstream tension roller 6 is a metal roller. The downstream tension roller 5 and the upstream tension roller 6 are both grounded. The downstream tension roller 5 has a small diameter suitable for separating the sheet from the suction belt 2 by the curvature. That is, by setting the diameter of the downstream tension roller 5 to be small and increasing the curvature, the sheet adsorbed and conveyed by the suction belt 2 is separated from the downstream tension roller 5 and guided downstream in the conveyance direction. It can enter the conveyance path H formed by the member 10.

  Further, as shown in FIG. 5, the shaft 5 a of the downstream tension roller 5 is rotatably supported by the housing 20. The shaft 6 a of the upstream tension roller 6 is rotatably supported by a bearing 22 that is slidably held in the sheet conveyance direction with respect to the housing body 20 a of the housing 20. The bearing 22 is urged to the upstream side in the sheet conveying direction by a spring 21. As a result, the upstream tension roller 6 is urged to the upstream side in the sheet conveying direction, and tension is applied to the suction belt 2.

  FIG. 6 is an exploded view of the housing 20. One of the two shaft hole portions 20b that support the shaft 5a of the downstream tension roller 5 provided in the housing 20 is provided separately from the housing main body portion 20a of the housing 20, and is provided with a fixing screw. One shaft hole 20b is attached to the housing body by 20c. When the housing 20 is assembled to the shaft 5a of the downstream tension roller 5, one shaft hole 20b is removed from the housing main body, and the shaft 5a of the downstream tension roller 5 is pivotally supported to the other shaft hole 20b. Let Thereafter, the shaft 5a of the downstream tension roller 5 is pivotally supported by the one removed shaft hole 20b, and the one shaft hole 20b is attached and fixed to the housing body 20a with the fixing screw 20c.

  As shown in FIGS. 3 and 4, the adsorption separation unit 110 is provided with brackets 12 at both ends in the belt width direction for holding the adsorption belt 2 in a swingable manner. Each bracket 12 is rotatably supported by a support shaft 14 provided on the upstream side in the sheet conveying direction from the upstream tension roller 6. As a result, the adsorption separation unit 110 can be swung between the suction position and the transport position with the support shaft 14 as a fulcrum by a swing mechanism 120 described later. The adsorption position is a position where the uppermost sheet 1a of the sheet bundle 1 is adsorbed to the adsorption belt 2, and the conveyance position is a position where the uppermost sheet 1a adsorbed to the adsorption belt 2 is conveyed.

  Each bracket 12 is provided with a long hole 12a, and the shaft 6a of the upstream tension roller 6 passes through the long hole 12a. Thereby, the upstream tension roller 6 is held movably with respect to the bracket 12. On the other hand, the shaft 5 a of the downstream tension roller 5 passes through a hole (not shown) provided in the bracket 12, and the downstream tension roller 5 is held immovably with respect to the bracket 12. As shown in FIG. 4, when the adsorption separation unit 110 is in the transport position, the shaft 6a of the upstream tension roller 6 abuts against the lower end surface 41a of the long hole 12a.

  The long hole 12a provided in the bracket 12 is configured so that the rotation center of the upstream tension roller 6 and the rotation center of the downstream tension roller 5 are rotated even if the shaft 6a of the upstream tension roller 6 moves in the long hole 12a. The arcuate shape is centered on the rotation center of the downstream tension roller 5 so that the distance to the center of the roller does not change. As a result, even if the upstream tension roller 6 moves in the long hole 12a, the tension of the suction belt 2 does not change.

  Normally, even if the tension of the suction belt 2 is 5 [N] or less, the suction belt 2 is driven to rotate and does not slip between each of the stretching rollers 5 and 6 and the suction belt 2 and is sucked to the suction belt 2. It is possible to convey the uppermost sheet 1a. On the other hand, when a sheet having a special condition such as a sheet having a high adhesion force is conveyed, it is conceivable that slip occurs between the stretching rollers 5 and 6 and the suction belt 2. For this reason, it is preferable to increase the friction coefficient of the surface of the upstream tension roller 6 and the surface of the downstream tension roller 5 with respect to the suction belt 2 so that slip is not easily generated.

FIG. 7 is a schematic configuration diagram of a drive mechanism 130 that rotationally drives the suction belt 2.
A driven first pulley 26a and a driving second pulley 26b are fixed to one end of a support shaft 14 that rotatably supports each bracket 12. A driven second pulley 25 is fixed to one end of the downstream tension roller 5, and a driven timing belt 28 is wound around the driven first pulley 26 a and the driven second pulley 25. A drive motor 24 is provided on the upstream side of the support shaft 14 in the sheet conveying direction, and a drive first pulley 27 is fixed to the motor shaft 24 a of the drive motor 24. A drive timing belt 29 is wound around the drive first pulley 27 and the drive second pulley 26b.

  When the drive motor 24 is driven, the downstream tension roller 5 is rotationally driven via the drive timing belt 29 and the driven timing belt 28. As a result, the suction belt 2 is rotationally driven, and the upstream tension roller 6 is driven to rotate by friction of the inner peripheral surface of the suction belt 2.

  In the present embodiment, the driving force of the driving motor 24 is transmitted to the downstream tension roller 5 through the support shaft 14 that supports the bracket 12. With this configuration, as will be described later, the adsorption / separation unit 110 swings with the support shaft 14 as a fulcrum, so that even if the adsorption / separation unit 110 swings, it supports the downstream tension roller 5. The distance from the shaft 14 does not vary. Therefore, the tension of the driven timing belt 28 is maintained and the driving force can be transmitted to the downstream tension roller 5 satisfactorily.

  The drive mechanism 130 may be configured so that the drive force is transmitted from the drive motor 24 to the upstream tension roller 6, and the upstream tension roller 6 may be used as a drive roller for rotating the suction belt 2.

  As shown in FIGS. 3 and 4, a swinging mechanism 120 is provided as a swinging unit that swings the bracket 12 on the downstream side of the sheet feeding unit 52 in the sheet conveying direction. The swing mechanism 120 has a rack gear portion 13 as a first drive transmission portion formed at a downstream end portion of each bracket 12 in the sheet conveyance direction, and a second drive transmission fixed to the rotary shaft 16 and meshing with the rack gear portion 13. And a pinion gear 15 as a member. The swing mechanism 120 includes a swing motor 30. A driven gear 32 that meshes with a motor gear 31 fixed to the motor shaft 30 a of the swing motor 30 is provided at one end of the rotating shaft 16.

  Further, by fixing each pinion gear 15 provided corresponding to each bracket 12 to the rotation shaft 16 that is the same shaft member, the rotation shaft 16 is rotated by the swing motor 30, so that each pinion gear 15 is rotated. Can be rotated. Thereby, the two pinion gears 15 provided at both ends in the belt width direction can be rotationally driven by one swing motor 30, the number of parts can be reduced, and the apparatus can be made inexpensive. In addition, with a simple configuration, it is possible to synchronize the drive of the rack and pinion provided at both ends in the belt width direction.

  The rack gear portion 13 has an R shape centered on the support shaft 14. The rack gear portion 13 formed on the bracket 12 swings around the support shaft 14 when the adsorption separation unit 110 swings. Therefore, by making the rack gear portion 13 R-shaped around the support shaft 14, the meshing between the rack gear portion 13 and the pinion gear 15 can be maintained even when the adsorption / separation unit 110 is swung.

  Further, by forming the rack gear portion at the downstream end of the bracket 12 in the sheet conveying direction, the number of parts can be reduced and the configuration can be simplified as compared with the case where the rack gear separate from the bracket 12 is attached to the bracket 12. Can do. Further, by providing a pinion on the device side of the rack and pinion of the swing mechanism 120, the configuration for transmitting the drive to the pinion is simplified compared to the case where the pinion is provided in the adsorption separation unit 110. be able to.

  In the swing mechanism 120 having such a configuration, by driving the swing motor 30, each pinion gear 15 rotates, and the rack gear portion 13 moves in a direction in which the rack gear portion 13 contacts and separates from the sheet bundle 1. Thereby, each bracket 12 swings around the support shaft 14 as a fulcrum.

  Each bracket 12 is connected and fixed by a reinforcing member 70. By connecting and fixing each bracket 12 with the reinforcing member 70, the one bracket 12 and the other bracket 12 can be integrally swung. Thus, the suction belt 2 held by each bracket 12 is prevented from being twisted when the bracket is swung, and the uppermost sheet 1a adsorbed to the suction belt 2 is prevented from being separated from the suction belt 2. Can do.

  As shown in FIG. 8, a roller-shaped charging member 3 as a charging unit that charges the surface of the suction belt 2 is in contact with the surface of the suction belt 2. The charging member 3 is rotatably provided in the adsorption separation unit 110, and the position with respect to the adsorption belt 2 is uniquely determined. The charging member 3 is connected to a charging power source 4 that generates alternating current.

  In this embodiment, the roller-shaped charging member 3 is used as the charging means, but a blade-shaped electrode member 103 as shown in FIG. 9 may be used. By making the electrode member 103 into a blade shape, it becomes possible to form a charge pattern with a smaller pitch width compared to the roller-shaped charging member 3, and the adsorption power of the stacked sheet bundle to the uppermost sheet 1 a increases rapidly. In addition, the decrease in the attractive force acting on the second and subsequent sheets is accelerated. Therefore, it is advantageous in that the time required for the separation operation can be shortened. Further, the alternating charging interval can be easily reduced in pitch, and stable charging can be performed even if the suction belt 2 has a minute wave.

  Next, a sheet conveying operation using the sheet conveying apparatus 200 of the present embodiment will be described with reference to FIG.

  As shown in FIG. 10A, the bottom plate 7 is normally in the lowered position, and the adsorption separation unit 110 is in the adsorption position. First, when a paper feed signal is input, the swing motor 30 (see FIG. 3) is driven to rotate the pinion gear 15 in the clockwise direction in the figure, and the support shaft 14 is supported as a counterclockwise direction in the figure (sheet bundle). The adsorption separation unit 110 is swung in the direction away from 1. When the adsorption / separation unit 110 swings to the transport position, the drive of the swing motor 30 is stopped.

  As shown in FIG. 10B, when the suction separation unit 110 stops at the transport position, the drive motor 24 (see FIG. 3) is driven to move the suction belt 2 endlessly. Next, an alternating voltage is applied to the suction belt 2 that moves endlessly by the charging power source 4 via the charging member 3, and a pitch (pitch is determined) on the surface of the suction belt 2 according to the AC power source frequency and the circumferential speed of the suction belt 2. 5 [mm] to 15 [mm] is preferable, and an alternating charge pattern is formed. In addition to alternating current, the charging power source 4 may be one in which direct current is changed to high and low alternate potentials, such as a rectangular wave and a sine wave. In the present embodiment, a rectangular wave having an amplitude of 4 [kV] is applied to the surface of the suction belt 2.

  When charging of the suction belt 2 is completed, as shown in FIG. 10C, the rotation of the suction belt 2 is stopped and the bottom plate 7 that has been waiting at the lowered position is started to rise. Further, before and after this, the swing motor 30 is rotated in the reverse direction, the pinion gear 15 is rotated counterclockwise in the figure, and the support shaft 14 is used as a fulcrum in the clockwise direction in the figure (direction approaching the sheet bundle 1). The adsorption separation unit 110 is swung.

  When the bottom plate 7 is raised and the suction separation unit 110 is lowered, the uppermost sheet 1a of the sheet bundle 1 comes into contact with the upstream tension roller 6 via the suction belt 2. Further, when the bottom plate 7 is raised and the adsorption separation unit 110 is lowered, the upstream tension roller 6 is pushed up by the sheet bundle 1 and is in contact with the lower end surface 41a of the long hole 12a. 6 moves upward while being guided by the long hole 12a. Further, as the bottom plate 7 is raised, the filler 44 rotates counterclockwise in the drawing. When the uppermost sheet 1a of the sheet bundle 1 comes to a predetermined position, the filler 44 blocks the light from the light emitting portion 43b of the transmissive optical sensor 43, and the transmissive optical sensor 43 becomes the uppermost sheet of the sheet bundle 1. It is detected that 1a has reached a predetermined position, and the rising of the bottom plate 7 is stopped.

  Further, when the adsorption separation unit 110 reaches the adsorption position, the rotation of the swing motor 30 is stopped. When the swing motor 30 is a stepping motor, the suction separation unit 110 can be accurately stopped at the suction position by controlling the swing motor 30 based on the rotation angle (number of pulses). When the swing motor 30 is a DC motor, the adsorption / separation unit 110 can be accurately stopped at the suction position by controlling the swing motor 30 based on the driving time.

  As shown in FIG. 10D, when the rise of the bottom plate 7 is stopped and the lowering (swinging) of the adsorption separation unit 110 is stopped, the region facing the sheet bundle 1 of the adsorption belt 2 is the maximum of the sheet bundle 1. It contacts the upper sheet 1a. When the suction belt 2 comes into contact with the uppermost sheet 1a, Maxwell's stress acts on the dielectric sheet due to an unequal electric field formed by the charge pattern on the surface of the suction belt 2, and the uppermost sheet of the sheet bundle 1 1a is adsorbed to the adsorbing belt 2.

  In the state shown in FIG. 10 (d), when the uppermost sheet 1 a is adsorbed to the adsorbing belt 2, the swing motor 30 is driven to rotate the pinion gear 15 clockwise to adsorb and separate unit 110. Is pivoted counterclockwise in the figure with the support shaft 14 as a fulcrum. Then, the downstream tension roller 5 moves together with the bracket 12 in a direction away from the sheet bundle 1.

  On the other hand, the upstream tension roller 6 does not move from the upper surface of the sheet bundle 1 due to its own weight, but moves relative to the bracket 12 in the sheet bundle direction. Accordingly, the suction belt 2 moves so as to swing around the rotation center of the upstream tension roller 6, and the uppermost sheet 1 a adsorbed to the suction belt 2 is stretched upstream of the suction belt 2. The portion wound around the gantry roller 6 is bent around a fulcrum. As a result, the restoring force acts on the sheet adsorbed on the adsorption belt 2, and only the uppermost sheet 1a can be adsorbed on the adsorption belt 2, and the second sheet 1b can be separated by the restoring force of the sheet.

  When the adsorption separation unit 110 further rotates counterclockwise in the drawing with the support shaft 14 as a fulcrum, the shaft 6a of the upstream tension roller 6 abuts against the lower end surface 41a of the long hole 12a. As described above, when the upstream separation roller 6 is further rotated from the state where the upstream tension roller 6 hits the lower end surface 41a of the long hole 12a, the upstream tension roller 6 also moves together with the bracket 12, The side tension roller 6 is separated from the upper surface of the sheet bundle 1.

  As shown in FIG. 10E, when the suction separation unit 110 reaches the conveyance position for conveying the sheet, the drive of the swing motor 30 is stopped. Then, the drive motor 24 is driven to move the suction belt 2 endlessly, and the uppermost sheet 1 a sucked on the suction belt 2 is transported toward the transport roller pair 9. When the leading edge of the uppermost sheet 1a electrostatically attracted to the suction belt 2 reaches the winding portion of the downstream tension roller 5 of the suction belt 2, it is separated from the suction belt 2 by curvature separation and guided to the guide member 10. However, it moves toward the conveyance roller pair 9 (see FIG. 10E).

  The linear velocity of the conveyance roller pair 9 and the suction belt 2 is the same, and when the conveyance roller pair 9 is intermittently driven at a timing, the drive motor so that the adsorption belt 2 is also intermittently driven. 24 is controlled. Alternatively, the drive of the suction belt 2 may be controlled by providing an electromagnetic clutch in the drive mechanism 130 and controlling the electromagnetic clutch.

  The sheet adsorbing force due to the charge pattern acts only on the uppermost sheet 1a and does not act on the second and lower sheets 1b and below. In this paper feeding method, since the frictional force between the pickup means and the paper is not used, the contact pressure between the suction belt 2 and the sheet bundle 1 can be sufficiently reduced, so that double feeding due to friction does not occur.

  The suction belt 2 is separated from the sheet bundle 1 before the rear end of the uppermost sheet 1 a reaches the position facing the upstream tension roller 6, so that the second sheet 1 b is not sucked by the suction belt 2.

  Further, the suction belt 2 is charged by the length of the conveying roller pair 9 from the sheet separation position of the suction belt 2, and thereafter, the suction belt 2 is neutralized by the charging member 3. Also good. Thus, after the sheet is conveyed to the conveying roller pair 9, the sheet is conveyed only by the conveying force of the conveying roller pair 9 without being affected by the suction belt 2. Further, by neutralizing the suction belt 2, it is possible to suppress the second sheet 1 b from being electrostatically attracted to the separated suction belt 2.

  In the present embodiment, the bracket 12 is provided with a long hole 12a, and the shaft 6a of the upstream tension roller 6 is held in the long hole 12a. However, the present invention is not limited to this, and the upstream tension roller 6 is held swingably with respect to the bracket 12 around the downstream tension roller 5. In addition, when the suction separation unit 110 is in the feeding position, the upstream tension roller 6 may be supported so that the inclination angle of the suction belt 2 with respect to the upper surface of the sheet bundle is a predetermined angle.

  In the present embodiment, the uppermost sheet is electrostatically adsorbed to the adsorption belt 2 and the uppermost sheet is separated from the second sheet. Therefore, as in the separation method using the frictional force, the sheet friction Double feed does not occur due to the influence of the coefficient.

  Further, in the present embodiment, the adsorption separation unit 110 is swung by the meshing of the pinion gear 15 and the rack gear portion 13. Thus, both the swing from the suction position to the feeding position and the swing from the feeding position to the suction position can be performed by the driving force of the swing motor 30, and the speed of the free fall of the suction separation unit 110 can be increased. The adsorption separation unit can be lowered to the adsorption position quickly. Therefore, after the first sheet is conveyed, the next sheet suction operation can be started quickly, and the sheet interval can be shortened. Thereby, productivity can be improved.

  Further, in this embodiment, the swing mechanism 120 is provided on the downstream side in the sheet conveying direction away from the support shaft 14 that is the swing support point of the adsorption separation unit 110. As a result, the downstream side in the sheet conveyance direction of the adsorption separation unit 110 can be supported by the engagement of the pinion gear 15 and the rack gear portion 13. As a result, the adsorption / separation unit 110 is supported at both ends by the support shaft 14 and the swing mechanism 120, and vibration of the adsorption / separation unit 110 can be suppressed compared to the case where the adsorption / separation unit 110 is cantilevered. it can. Thereby, it is possible to prevent the uppermost sheet 1a adsorbed to the adsorption belt 2 from being separated from the adsorption belt 2 due to the vibration of the adsorption separation unit 110.

  In addition, the driving force is transmitted to the adsorption separation unit 110 at the end on the downstream side in the sheet conveying direction farthest from the support shaft 14, which is the fulcrum of the adsorption separation unit 110, and the adsorption separation unit 110 is oscillated. Yes. Thus, by separating the driving force transmission portion from the support shaft 14, compared to the case where the driving force is transmitted on the support shaft side (upstream side in the sheet conveyance direction of the suction separation unit 110) by the lever principle, The adsorption separation unit 110 can be oscillated with a small load. Thereby, the enlargement of the swing motor 30 can be avoided, and the enlargement of the apparatus can be suppressed. Further, the wear of the meshing portion between the pinion gear 15 and the rack gear portion 13 can be suppressed.

  Further, a pinion gear 15 and a rack gear portion 13 are provided at the downstream end portion of the adsorption separation unit 110 in the sheet conveying direction. Accordingly, as shown in FIG. 11, the meshing position K between the pinion gear 15 and the rack gear portion 13 can be provided downstream of the gravity center P of the adsorption separation unit 110 in the sheet conveying direction.

  When the meshing position K is upstream of the center of gravity P of the suction separation unit 110 in the sheet conveyance direction, the free end side that is not supported by the meshing of the support shaft 14 and the swing mechanism (downstream of the meshing position in the sheet conveyance direction). ) Is located at the center of gravity P of the adsorption separation unit 110. As a result, when the adsorption / separation unit 110 is swung, the free end (the downstream end in the sheet conveying direction) of the adsorption / separation unit 110 moves from the meshing position K to the center of gravity P due to the influence of the inertia of the adsorption / separation unit itself. It will elastically vibrate according to the distance. Further, since the center of gravity P is on the free end side, the amplitude when the adsorption / separation unit 110 elastically vibrates increases, and the convergence of the vibration also slows down.

  However, as in the present embodiment, the meshing position K is provided on the downstream side of the gravity center P of the adsorption / separation unit 110 in the sheet conveying direction, whereby the elastic vibration of the adsorption / separation unit 110 can be changed to the elastic vibration of both end support. Can be reduced and convergence can be accelerated.

  Further, since the position of the adsorption / separation unit 110 is held by meshing with the rack gear portion 13 of the pinion gear 15, the position of the adsorption / separation unit can be controlled with high accuracy by controlling the swing motor 30 with high accuracy. Thereby, the adsorption separation unit 110 can be accurately positioned at the feeding position.

  In particular, in the present embodiment, the swing mechanism 120 is provided on the downstream side in the sheet conveying direction, and is provided at a position away from the support shaft 14 that is a swing support point. Thereby, compared with the case where it provides in the support shaft 14 side (sheet conveyance direction upstream side), the moving amount | distance of the adsorption separation unit 110 per pitch can be decreased. Therefore, the position control of the adsorption separation unit 110 with higher accuracy can be performed. As a result, the adsorption separation unit 110 can be accurately positioned at the target feeding position, and the uppermost sheet 1a can be smoothly conveyed to the nip of the conveying roller pair 9. As a result, it is possible to prevent the leading end of the uppermost sheet 1a from abutting against the conveying roller pair 9 and being separated from the suction belt due to vibration at that time.

  Further, by providing the rack gear portion 13 and the pinion gear 15 at both ends in the belt width direction, the bell and both ends in the width direction of the adsorption separation unit 110 are supported by meshing of the rack gear portion 13 and the pinion gear 15. Thereby, the twist of the adsorption separation unit 110 can be suppressed. Moreover, as shown in FIG. 12, the structure which provided the rack and pinion mechanism only in the belt width direction one end side may be sufficient.

[Modification 1]
FIG. 13 is a schematic configuration diagram illustrating a sheet conveying apparatus 200A according to the first modification. FIG. 14 is a schematic configuration diagram illustrating the driving mechanism 130 and the swing mechanism 120 of the sheet conveying apparatus 200A according to the first modification. In FIG. 14, the suction belt 2 and the like are not shown.

  As shown in FIG. 13, the sheet conveying apparatus 200 </ b> A according to the first modification includes a pinion gear 145 provided in the bracket 12 and a rack gear 146 provided in the apparatus main body in the rack and pinion of the swing mechanism 120.

  As shown in FIG. 14, the pinion gear 145 is rotatably supported on the shaft 5 a of the downstream tension roller 5. The pinion gear 145 is provided with a pulley portion 145 a, and a first timing belt 48 is wound around the pulley portion 145 a and a driven pulley 47 provided on the support shaft 14. A second timing belt 49 is wound around the driven pulley 47 and a drive pulley 310 provided on the motor shaft of the swing motor 30. Accordingly, the driving force of the swing motor 30 can be transmitted to the pinion gear 145 via the support shaft 14. Therefore, similarly to the drive mechanism 130 described above, the first timing belt 48 is not slackened by the swing of the adsorption separation unit 110, and the driving force of the swing motor 30 can be transmitted to the pinion gear 145 satisfactorily.

  The configuration in which the pinion gear 145 is provided in the adsorption / separation unit 110 as in Modification 1 is an advantageous configuration when the amount of swing of the adsorption / separation unit is large. The rack gear needs to be increased according to the swing amount of the adsorption / separation unit, but the pinion gear can be made constant regardless of the swing amount of the adsorption / separation unit. Therefore, an increase in the size of the adsorption / separation unit can be avoided, and an increase in load during oscillation due to an increase in the weight of the adsorption / separation unit can be suppressed. Therefore, when the amount of oscillation is large, the configuration of the first modification can be used to increase the oscillation speed of the adsorption separation unit 110 and increase productivity.

[Modification 2]
FIG. 15 is a schematic configuration diagram of a sheet conveying apparatus 200B according to the second modification. FIG. 16 is a schematic configuration diagram illustrating the swing mechanism 120 of the sheet conveying apparatus 200B according to the second modification.

  The sheet conveying apparatus 200B according to Modification 2 includes a position P of the center of gravity of the adsorption / separation unit 110 in the sheet conveyance direction, the rack gear portion 13 of the swing mechanism 120, and the pinion gear 15 when the adsorption / separation unit 110 is at the feeding position. The meshing position K is the same position. In the second modification, as shown in FIG. 16, when the suction separation unit 110 is in the feeding position, the position P of the center of gravity and the meshing position K are set to the same position. A step portion is provided at the downstream end portion, and the rack gear portion 13 is formed at the step portion.

  When the adsorption separation unit 110 stops at the feeding position, it is elastically vibrated by the inertia of the adsorption separation unit 110. In particular, when the adsorption / separation unit 110 is swung at a high speed in order to increase productivity, the influence of the inertia of the adsorption / separation unit 110 increases, and the elastic vibration tends to increase. When the adsorption separation unit 110 elastically vibrates at the feeding position, the uppermost sheet 1a adsorbed on the adsorption belt 2 may be separated from the adsorption belt 2.

  Therefore, in this modified example 2, when the adsorption separation unit 110 is at the feeding position, the position P of the center of gravity and the meshing position K are set to the same position, so that the adsorption separation unit 110 is at the feeding position. Elastic vibration when stopped can be most effectively suppressed. Therefore, it is possible to suppress the uppermost sheet 1a from being separated from the suction belt 2.

[Modification 3]
FIG. 17 is a schematic configuration diagram of a sheet conveying apparatus 200 </ b> C according to the third modification.
As shown in the figure, the sheet conveying apparatus 200C of the third modification makes the upstream tension roller 6 immovable with respect to the bracket 12, and sets the feeding position of the adsorption separation unit according to conditions such as the thickness of the sheet. To change.

  The upstream tension roller 6 is held swingably with respect to the bracket 12 around the downstream tension roller 5, and when the suction separation unit 110 is at the feeding position, the upstream tension roller 6 is Consider a configuration that abuts the lower end 41 of the long hole 12a. In this configuration, the inclination angle of the suction belt 2 with respect to the sheet bundle 1 at the time of feeding is always constant. Therefore, for example, when the sheet is stiff, such as thick paper, the uppermost sheet 1a may be peeled off from the suction belt 2.

  Therefore, in the third modification, the upstream tension roller 6 is supported so as not to move with respect to the bracket 12, and the adsorption / separation unit 110 is varied in the swinging range according to conditions such as the paper thickness. The feeding position of the separation unit 110 is varied. In this case, if the rotating shaft 16 that fixes the pinion gear 15 is within the swinging range (the enclosed range in FIG. 17) of the adsorption separation unit 110, the rotating shaft 16 may interfere with feeding depending on the feeding position. It becomes. Therefore, in this case, it is preferable to provide the rotating shaft 16 outside the swinging range of the adsorption separation unit 110 as shown in FIG. Further, as shown in FIG. 18, the swing motors 30 may be provided at both ends in the belt width direction. Even if it comprises in this way, the rocking | fluctuation mechanism 120 does not interfere with feeding.

[Example 1]
FIG. 1A is a schematic diagram showing a state where the adsorption separation unit 110 is located at the adsorption position. FIG. 1B is a schematic view when one end side in the sheet width direction orthogonal to the sheet conveyance direction of the adsorption separation unit 110 is viewed from above.

  In this embodiment, as shown in FIG. 1A, the pressing member 35A and the pressing member 35B that press the suction belt 2 toward the sheet bundle 1 at the suction position are arranged inside the suction belt 2 in the sheet conveyance direction. It is provided along. The pressing member 35 </ b> A is provided on the downstream side in the sheet conveying direction in the suction belt 2, and the pressing member 35 </ b> B is provided on the upstream side in the sheet conveying direction in the suction belt 2. Further, the contact surface 35Af and the contact surface 35Bf of the pressing member 35A and the pressing member 35B with the suction belt 2 have curved surfaces.

  As shown in FIG. 1B, the pressing members 35A and 35B are rotatably provided on the shaft 5a of the downstream tension roller 5 via the shaft hole portions 35Ad and 35Bd. At the time of sheet suction, the pressing members 35A and 35B press the suction belt 2 from the inner side to the outer side by the weight of the pressing member itself and the urging force of the compression springs 36A and 36B. Press against the upper surface of the upper sheet 1a. As a result, the gap between the suction belt 2 and the uppermost sheet 1a is prevented from being generated between the suction belt 2 and the uppermost sheet 1a, thereby ensuring the contact between the suction belt 2 and the uppermost sheet 1a. can do.

  Further, by providing a plurality of pressing members 35A, 35B along the sheet conveying direction inside the suction belt 2, the following effects can be obtained. That is, it is possible to increase the pressing area of the suction belt 2 by the pressing member 35A and the pressing member 35B in the sheet conveying direction, compared to the case where one roller member is provided as a conventional pressing member. Therefore, the contact area between the suction belt 2 and the uppermost sheet 1a in the sheet conveying direction can be secured more than when only one pressing member and roller member are provided. Adsorbability can be increased.

  The width of the pressing members 35A and 35B in the sheet conveying direction is preferably as wide as possible. For example, the width of the pressing member 35 </ b> A and the pressing member 35 </ b> B in the sheet conveying direction is adjusted to be about 70% to 80% of the stretching region of the suction belt 2 by the downstream stretching roller 5 and the upstream stretching roller 6. Good to do. Thereby, the pressing area of the suction belt 2 by the pressing member 35 can be ensured as compared with the case where a roller member is used as the pressing member.

  FIG. 19 is a diagram for explaining various configurations of the pressing member 35 </ b> A and assembly to the bracket 12. Note that various configurations of the pressing member 35B and how to assemble the pressing member 35B to the bracket 12 are the same as those of the pressing member 35A, and thus description thereof is omitted.

  As shown in FIG. 19, the pressing member 35 </ b> A is provided at a plate-like pressing member main body portion 35 </ b> Aa to be brought into contact with the suction belt 2 and at both ends in the sheet width direction of the pressing member main body portion 35 </ b> Aa, and is held by the long holes 12 b of the bracket 12. The two holding portions 35Ab are provided. On the upper surface of each of the two holding portions 35Ab, a convex compression spring installation portion 35Ac on which a compression spring 36A that is an elastic member that elastically biases the pressing member 35A is installed is provided. Further, two shaft hole portions 35Ad each having a shaft hole into which the shaft 5a of the downstream tension roller 5 is inserted are provided on the downstream side of the pressing member main body portion 35Aa in the sheet conveying direction.

  One of the shaft hole portions 35Ad is provided separately from the pressing member main body portion 35Aa, and the one shaft hole portion 35Ad is attached to the pressing member main body portion 35Aa by a fixing screw 35Ae. When the pressing member 35A is assembled to the shaft 5a of the downstream tension roller 5, one shaft hole 35Ad is removed from the pressing member main body 35Aa, and the shaft 5a of the downstream tension roller 5 is inserted into the other shaft hole 35Ad. To support. Thereafter, the shaft 5a of the downstream tension roller 5 is pivotally supported by the removed one shaft hole 35Ad, and the one shaft hole 35Ad is attached and fixed to the pressing member main body 35Aa by the fixing screw 35Ae.

  One end of the compression spring 36A is fitted and connected to a compression spring installation portion 35Ac that is a convex shape of the pressing member 35A, and the other end of the compression spring 36A is an upper portion in the long hole 12b provided in the bracket 12 of the adsorption separation unit 110. Connected to the end face.

  FIG. 20 is a view of the adsorption separation unit 110 when the compression springs 36A and 36B are provided at the position of the bracket 12 as viewed from above. As shown in FIG. 20, the pressing members 35 </ b> A and 35 </ b> B are urged by compression springs 36 </ b> A and 36 </ b> B provided at both ends of the adsorption separation unit 110 in the sheet width direction, in other words, at the position of the bracket 12. .

  The length of the pressing members 35A and 35B in the sheet width direction is not changed if the length is equal to or greater than the sheet bundle, but is most effective when covering the entire area. Therefore, in the present embodiment, the widths of the pressing members 35A and 35B in the sheet width direction are larger than the maximum sheet width corresponding to the sheet conveying apparatus 200. When turning the uppermost sheet 1a of the sheet bundle 1, it is possible to suppress the air resistance by turning from the end of the sheet, and it is not necessary to bend or deform the sheet. The upper sheet 1a can be turned from the sheet bundle. Therefore, by setting the width of the pressing members 35A and 35B in the sheet width direction to be larger than the maximum sheet width corresponding to the sheet conveying apparatus 200, the pressing members 35A and 35B with respect to all size sheets corresponding to the sheet conveying apparatus. The effect of can be demonstrated.

  In FIG. 21, compression springs 36A and 36B are provided in a portion of the housing 20 located inside the suction belt 2 on the inner side in the seat width direction than each bracket 12, and the pressing members 35A and 35B are pushed by the compression springs 36A and 36B. It has a configuration.

  As shown in FIG. 20 and the like, the installation positions of the compression springs 36A and 36B are most suitable for assembling and exchanging. However, when a cut sheet such as an A4 horizontal sheet or an A3 vertical sheet having a sheet width of 297 [mm] is to be adsorbed, the compression springs 36A, 36A, It is better to provide 36B. That is, the compression springs 36 </ b> A and 36 </ b> B are provided on the portion of the housing 20 located inside the suction belt 2. Thereby, the effect of ensuring the adsorptivity becomes higher than the case where the compression springs 36A and 36B are provided on the brackets 12 at both ends in the sheet width direction of the adsorption separation unit 110 and pressed.

  The lowering amount of the pressing member 35A and the pressing member 35B is larger in the pressing member 35A than in the pressing member 35B. This is possible by setting the abutting portions of the pressing member 35A and the pressing member 35B to the bracket 12 to be the same or close to each other.

  FIG. 22 shows the operation of the adsorption separation unit 110 from the time of adsorption to the time of conveyance.

  Further, FIG. 23 shows a schematic diagram when the suction separation unit 110 omits the illustration of the pressing members 35 </ b> A and 35 </ b> B, the compression spring 36, etc., and pays attention to the housing 20. Specifically, FIG. 23A is a schematic diagram showing a state where the adsorption separation unit 110 is located at the adsorption position. FIG. 23B is a schematic diagram illustrating a state in which the adsorption separation unit 110 is located at the transport position.

  In FIG. 24, the upstream separation roller 6, the housing 20, the suction belt 2, and the like are omitted in the suction separation unit 110 and attention is paid to the pressing members 35 </ b> A and 35 </ b> B and the compression springs 36 </ b> A and 36 </ b> B. Show. Specifically, FIG. 24A is a schematic diagram showing a state where the adsorption separation unit 110 is located at the adsorption position. FIG. 24B is a schematic diagram showing a state where the adsorption separation unit 110 is located at the transport position.

  As shown in FIG. 22A, at the suction position, the suction belt 2 is pressed against the uppermost sheet 1a by the pressing members 35A and 35B. At this time, the shaft 6a of the upstream tension roller 6 and the holding portions 35Ab, 35Bb of the pressing members 35A, 35B are separated from the lower end surfaces 41a, 41b, 41c of the long holes 12a, 12b, 12c provided in the bracket 12, respectively. doing.

  When the suction separation unit 110 is swung from the suction position to the transport position and lifted, the shaft 6a of the upstream tension roller 6 and the holding portions 35Ab and 35Bb of the pressing members 35A and 35B are respectively connected to the long holes 12a, 12b, It moves downward in 12c. As shown in FIG. 22 (b), the holding portions 35Ab and 35Bb of the pressing members 35A and 35B abut against the lower end surfaces 41b and 41c of the long holes 12b and 12c before the shaft 6a of the upstream tension roller 6. Held.

  Further, when the adsorption / separation unit 110 is swung toward the transport position and the adsorption / separation unit 110 is raised, the pressing members 35A and 35B move upward against the urging force of the compression springs 36A and 36B. Further, along with the movement of the pressing members 35A and 35B, as shown in FIG. 22 (c), the shaft 6a of the upstream tension roller 6 moves downward in the long hole 12a and hits the lower end surface 41a. By being held, the pressing members 35 </ b> A and 35 </ b> B are separated from the inner peripheral surface of the suction belt 2.

  In this configuration example, the movement amount of the upstream tension roller 6 due to the swinging operation of the suction separation unit 110 from the suction position to the transport position is smaller than the movement amount of the pressing members 35A and 35B. Then, by providing such a difference in the amount of movement, the contact timing between the shaft 6a of the upstream tension roller 6 and the lower end surface 41a of the long hole 12a, the holding portions 35Ab and 35Bb of the pressing members 35A and 35B, and the long holes The contact timing with the lower end surfaces 41b and 41c of 12b and 12c is varied. Thus, the pressing members 35 </ b> A and 35 </ b> B are configured to be separated from the inner peripheral surface of the suction belt 2. That is, while the suction separation unit 110 moves from the suction position to the transport position, the pressing members 35A and 35B move upward at the relative position from the upstream tension roller 6, so that the inner peripheral surface of the suction belt 2 The pressing members 35A and 35B are separated from each other.

  When pressing is performed from the inside of the suction belt 2 toward the upper surface of the sheet bundle by the pressing members 35A and 35B, if the suction belt 2 and the pressing members 35A and 35B are in contact with each other when the suction belt 2 rotates, the suction belt 2 and the pressing members 35A and 35B rub against each other. At this time, if the frictional force between the suction belt 2 and the pressing members 35A and 35B is larger than the frictional force between the suction belt 2 and the downstream tension roller 5, the following problem may occur. That is, a rotational load is applied to the suction belt 2 due to a frictional force generated between the suction belt 2 and the pressing members 35A and 35B, and slip occurs between the suction belt 2 and the downstream tension roller 5 to cause the suction belt. 2 will cause rotation failure.

  Therefore, “use a material with low sliding resistance for the pressing members 35A, 35B”, “reduce the contact area of the pressing members 35A, 35B with the suction belt 2”, “press the pressing members 35A, 35B against the suction belt 2”. It is conceivable to take measures such as reducing the pressure. However, in this case, there is a limit to the configuration that can be adopted. If there is such a restriction, it becomes difficult to ensure the contact between the suction belt 2 and the uppermost sheet 1a by pressing the suction belt 2 with the original pressing members 35A and 35B.

  On the other hand, in the present configuration example, the pressing member 35A, 35B can be switched between a contact state and a separation state with respect to the suction belt 2. That is, when the adsorption separation unit 110 is located at the adsorption position, the pressing members 35A and 35B are brought into contact with the adsorption belt 2 and pressed, and when the adsorption separation unit 110 is located at the transport position, the adsorption members 2A to 35A, 35B is separated.

  Thereby, when conveying the uppermost sheet 1a at the conveying position, the suction belt 2 can be rotated in a state where the pressing members 35A and 35B are separated from the suction belt 2. Therefore, it is not affected by the friction force generated between the suction belt 2 and the pressing members 35 </ b> A and 35 </ b> B, prevents the suction belt 2 from being subjected to a rotational load, and slips between the suction belt 2 and the downstream tension roller 5. It is possible to suppress the occurrence of rotation failure of the suction belt 2 due to the occurrence of the above. Therefore, the areas and pressures of the pressing members 35A and 35B necessary for ensuring the contact between the suction belt 2 and the uppermost sheet 1a can be set without causing the above-mentioned restriction. Therefore, the contact property between the suction belt 2 and the uppermost sheet 1a can be ensured while suppressing the rotation failure of the suction belt 2.

  Here, when the suction separation unit 110 is swung from the suction position to the transport position and the uppermost sheet 1 a is turned from the sheet bundle 1, the pressing members 35 </ b> A and 35 </ b> B are separated from the inner peripheral surface of the suction belt 2. Rubs between the pressing members 35 </ b> A and 35 </ b> B and the inner peripheral surface of the suction belt 2. And the rotational force which tries to rotate the adsorption | suction belt 2 generate | occur | produces by this rubbing.

  At this time, if the friction coefficient of the outer peripheral surface of the downstream tension roller 5 with respect to the inner peripheral surface of the suction belt 2 is lower than the friction coefficient of the pressing members 35A and 35B with respect to the inner peripheral surface of the suction belt 2, the rotational force causes The suction belt 2 slips with respect to the downstream tension roller 5. Thereby, there exists a possibility that the adsorption | suction belt 2 may rotate a little. Thus, if the suction belt 2 rotates, the leading end position of the uppermost sheet 1a sucked on the suction belt 2 is shifted from an appropriate position, which causes a conveyance failure.

  Therefore, in this configuration example, the friction coefficient of the outer peripheral surface of the downstream tension roller 5 with respect to the inner peripheral surface of the suction belt 2 is larger than the friction coefficient of the contact surface of the pressing members 35A and 35B with respect to the inner peripheral surface of the suction belt 2. Is high. Thereby, even if the said rotational force generate | occur | produces, it can suppress that the suction belt 2 does not slip with respect to the downstream tension roller 5, and the suction belt 2 rotates. As a result, it is possible to prevent the leading end position of the uppermost sheet 1a adsorbed to the adsorbing belt 2 from being shifted from an appropriate position and causing a conveyance failure.

  In the case of the configuration in which the uppermost sheet 1a is separated while being bent by the pressing members 35A and 35B, the portion before the bending point is uniformly spaced. If the area of this portion is large, the adsorption area of the uppermost sheet 1a by the adsorption belt 2 can be ensured, so that the adsorbability between the adsorption belt 2 and the uppermost sheet 1a can be ensured.

  On the other hand, since the area that needs to be peeled off at a time is large, it is disadvantageous for separating the uppermost sheet 1a from the sheet bundle. Therefore, considering the behavior for each paper type, thin paper tends to cause problems in separability instead of ensuring adsorbability. On the other hand, since it is possible to separate the cardboard by bending it a little, there is a concern that the uppermost sheet 1a may be peeled off from the suction belt 2 instead of easily securing the separability, which easily causes a problem in the adsorptivity. In particular, the pressing area of the suction belt 2 with a single pressing member is assured to be as large as 70% to 80% of the stretched area of the suction belt 2 by the downstream tension roller 5 and the upstream tension roller 6. However, it is difficult to cope with each paper type, and these problems become remarkable.

  FIG. 25A is a schematic diagram showing a state where the adsorption / separation unit 110 is located at the adsorption position when thin paper is used. FIG. 25B is a schematic diagram showing a state in which the adsorption / separation unit 110 swings from the adsorption position toward the conveyance position when thin paper is used.

When the suction separation unit 110 is swung from the suction position toward the transport position and the suction belt 2 is raised, if the uppermost sheet 1a is thin paper, the uppermost sheet 1a is bent by the pressing member 35A. Thereafter, the uppermost sheet 1a is further bent by the pressing member 35B. However, the uppermost sheet 1a, which is a thin paper, has the same effect as the bending by the pressing member 35A, and does not affect the separability and adsorbability. The thin paper here is assumed to be paper having a basis weight of 60 [g / m ² ] or less in a range mainly used in the image forming apparatus.

  FIG. 26A is a schematic diagram showing a state where the adsorption / separation unit 110 is located at the adsorption position when cardboard is used. FIG. 26B is a schematic diagram showing a state where the adsorption / separation unit 110 swings from the adsorption position toward the conveyance position when using thick paper.

When the uppermost sheet 1a is thick when the adsorption separation unit 110 is swung from the adsorption position toward the conveyance position and the adsorption belt 2 is raised, the uppermost sheet 1a is not bent by the pressing member 35A. It is configured to be bent by the member 35B. The uppermost sheet 1a, which is cardboard, sets the force that can withstand the pressing force from the pressing member 35A and the spring pressures of the compression springs 36A and 36B that bias the pressing members 35A and 35B. Therefore, when the uppermost sheet 1a is thick paper, the uppermost sheet 1a endures bending by the pressing member 35A, and then bends by the pressing member 35B.

  The force that the uppermost sheet 1a can withstand against the pressing force from the pressing member 35A is the adhesion force f between sheets, the sheet rigidity E, the sheet cross-sectional shape (second moment of section) I, and the length l of the part to be separated. It is determined by the relational expression. Further, the adhesion force f can be obtained from the result of an experiment conducted in advance assuming paper used in the apparatus main body and the use environment.

  In this embodiment, the pressing force of the pressing member 35B is larger than the pressing force of the pressing member 35A, and the pressing force of the pressing member 35A is not less than the stiffness of thin paper and not more than the stiffness of thick paper. Further, the pressing force of the pressing member 35B is larger than the stiffness of the cardboard. Thereby, when the uppermost sheet 1a is thin paper, the bending point of the uppermost sheet 1a becomes a position pressed by the pressing member 35A, and the uppermost sheet 1a is bent by the pressing member 35A. Therefore, the uppermost sheet 1a, which is a thin paper, can be tightly bent by the pressing member 35A, and the separability of the uppermost sheet 1a with respect to the sheet bundle 1 can be improved. When the uppermost sheet 1a is thin paper, even if the uppermost sheet 1a is bent tightly by the pressing member 35A, the uppermost sheet 1a is difficult to peel off from the suction belt 2 because the stiffness of the sheet is weak.

  On the other hand, when the uppermost sheet 1a is thick paper, the stiffness of the uppermost sheet 1a wins against the pressing force from the pressing member 35A, and the uppermost sheet 1a resists bending by the pressing member 35A, and the uppermost sheet 1a is bent. The point is a position pressed by the pressing member 35B. Thereby, the uppermost sheet 1a, which is a thick paper, is gently bent by the pressing member 35B, so that the uppermost sheet 1a, which is a thick paper, can be prevented from being bent and peeled off from the suction belt 2. Further, when the uppermost sheet 1a is thick paper, even if the uppermost sheet 1a is gently bent by the pressing member 35B, the uppermost sheet 1a can be separated from the sheet bundle 1 by the stiffness of the sheets.

[Example 2]
In this embodiment, as in the first embodiment, the pressing force of the pressing member 35B is larger than the pressing force of the pressing member 35A, and the pressing force of the pressing member 35A is not less than the stiffness of thin paper and not more than the stiffness of thick paper. The pressing force of the pressing member 35B is larger than that of cardboard.

  As shown in FIG. 27, also in this embodiment, the contact surfaces 35Af and 35Bf of the pressing members 35A and 35B with the suction belt 2 are curved, and the curvature of the contact surface 35Bf of the pressing member 35B is changed. The curvature of the contact surface 35Af of the pressing member 35A is smaller. In other words, the curvature radius of the contact surface 35Bf of the pressing member 35B is larger than the curvature radius of the contact surface 35Af of the pressing member 35A.

  By setting the radius of curvature of the contact surface 35Bf of the pressing member 35B to be large, the curvature of the uppermost sheet 1a bent by the pressing member 35B can be set gently. Therefore, when the uppermost sheet 1a is thick paper, the uppermost sheet 1a can be further prevented from being bent tightly by the pressing member 35B, and the uppermost sheet 1a can be further prevented from peeling off from the suction belt 2.

  On the other hand, when the uppermost sheet 1a is thin paper, the uppermost sheet 1a is bent by the pressing member 35A. Therefore, there is no difference in the influence of the separability and the adsorptivity due to the radius of curvature of the contact surface 35Bf of the pressing member 35B. In this embodiment, since the radius of curvature of the contact surface 35Af of the pressing member 35A is smaller than that of the pressing member 35B, the uppermost sheet 1a that is a thin paper can be bent more tightly by the pressing member 35A, and the uppermost sheet with respect to the sheet bundle 1 can be bent. The separability of the sheet 1a can be further improved.

  In addition, the pressing member 35A and the pressing member 35B can be separately designed to have the optimal pressing force for the sheet and the curvature of the contact surfaces 35Af and 35Bf.

[Embodiment 2]
A second embodiment in which the present invention is applied to a copying machine which is an electrophotographic image forming apparatus will be described below.

FIG. 28 is a schematic diagram showing the copying machine 100 according to the present embodiment.
The copying machine 100 includes an automatic document feeder 59 that separates documents one by one from a bundle of documents placed on a document tray 59a and automatically feeds them to a contact glass on a document reading unit 58. Further, a document reading unit 58 for reading a document conveyed on the contact glass by the automatic document conveyance device 59 is provided. The image forming unit 50 is an image forming unit that forms an image on the sheet fed from the sheet feeding unit 52 based on the document image read by the document reading unit 58. The sheet feeding unit 52 accommodates the sheet bundle 1 in which a plurality of sheets are stacked, and feeds the uppermost sheet 1 a located at the uppermost position from the sheet bundle 1 to the image forming unit 50. In the present embodiment, the image forming unit 50 and the paper feeding unit 52 can be divided.

  The image forming unit 50 includes a charging device 62, a developing device 64, a transfer device 54, a photoconductor cleaning device 65, and the like around a photoconductor 61 as a latent image carrier. The image forming unit 50 also includes an optical writing unit (not shown) for irradiating the photoreceptor 61 with a laser beam 63, a fixing device 55 for fixing the toner image on the sheet, and the like.

  In the image forming unit 50 configured as described above, as the photosensitive member 61 rotates, the surface of the photosensitive member 61 is first uniformly charged by the charging device 62. Next, a laser beam 63 from an optical writing unit (not shown) based on image data input from a personal computer, a word processor, or the like, or image data of a document read by the document reading unit 58 is irradiated onto the photoreceptor 61. An electrostatic latent image is formed. Thereafter, a toner image is formed on the photosensitive member 61 by attaching toner with the developing device 64 to visualize the electrostatic latent image. On the other hand, the sheet feeding unit 52 separates and conveys the sheets one by one, and stops against the registration roller 53. Then, in synchronization with the toner image formation timing of the image forming unit 50, the sheet that is pressed against the registration roller 53 and stopped is sent to the transfer unit where the photoconductor 61 and the transfer device 54 face each other.

  In the transfer unit, the toner image on the photoreceptor 61 is transferred to the supplied sheet. The sheet onto which the toner image has been transferred is fixed to the toner image by the fixing device 55 and then discharged to the paper discharge tray 57 by the paper discharge roller pair 56. On the other hand, the surface of the photoconductor 61 after the toner image transfer is cleaned by removing residual toner by the photoconductor cleaning device 65 to prepare for image formation again.

  FIG. 29 is a perspective view illustrating a schematic configuration of the paper feeding unit 52, and FIG. 30 is a schematic diagram illustrating the paper feeding unit 52. The paper feeding unit 52 is a sheet feeding cassette 11 serving as a sheet material accommodation unit that stacks and accommodates a plurality of sheets, and a sheet bundle 1 composed of a plurality of sheets on the paper feeding cassette 11 and located at the uppermost position. And a sheet conveying device 200 that separates and conveys the upper sheet 1a.

  As shown in FIG. 30, the paper feed cassette 11 has a bottom plate 7 on which a plurality of stacked sheet bundles 1 are stacked. A support member 8 that supports the bottom plate 7 is rotatably mounted between the bottom plate 7 and the bottom portion of the paper feed cassette 11.

  As shown in FIG. 29, the sheet feeding unit 52 is provided with a sheet detecting unit 40 that detects that the uppermost sheet 1a of the sheet bundle 1 has reached a predetermined position. The sheet detection means 40 includes a filler 44 that is rotatably supported by a shaft 42 provided in the apparatus main body, and a transmission optical sensor 43. When the support member 8 is rotated by a drive motor (not shown) to raise the bottom plate 7, the sheet bundle 1 stacked on the bottom plate 7 rises and the uppermost sheet 1 a comes into contact with the filler 44. At this time, the light receiving unit 43a of the transmissive optical sensor 43 receives light from the light emitting unit 43b. Further, when the bottom plate 7 is raised, the filler 44 blocks the light from the light emitting portion 43b, and the light receiving portion 43a does not receive the light. Thereby, it is detected that the uppermost sheet 1a of the sheet bundle 1 has come to a predetermined position, and the rotation of the support member 8 is stopped.

  The sheet conveying apparatus 200 includes an adsorption / separation unit 110, a swing mechanism 120 that is a swinging unit that swings the suction / separation unit 110, a drive mechanism 130 that moves the suction belt 2 endlessly, and the like. As shown in FIG. 5, the adsorption separation unit 110 includes an adsorption belt 2 that is stretched between a downstream tension roller 5 and an upstream tension roller 6.

The adsorption belt 2 has a surface layer made of polyethylene terephthalate with a thickness of about 50 [μm] having a resistance of 10 ⁸ [Ω · cm] or more, and a resistance of 10 ⁶ [Ω · cm] or less formed by aluminum vapor deposition. It has a two-layer structure having a conductive layer. By making the suction belt 2 have the two-layer structure as described above, the conductive layer can be used as a grounded counter electrode, and the charging member 3 serving as a charging means for applying a charge to the suction belt 2 is used as the suction belt 2. It can be provided anywhere as long as it is in contact with the surface layer. Further, a retaining rib 23 is provided on the inner side of both side edges of the suction belt 2 and is engaged with both side end surfaces of the rollers 5 and 6 to prevent the belt from shifting.

The downstream tension roller 5 is provided with a conductive rubber layer having a resistance value of 10 ⁶ [Ω · cm] on the surface, and the upstream tension roller 6 is a metal roller. Both the downstream tension roller 5 and the upstream tension roller 6 are grounded. The downstream tension roller 5 has a small diameter suitable for separating the sheet from the suction belt 2 by the curvature. That is, by setting the diameter of the downstream tension roller 5 to be small and increasing the curvature, the sheet adsorbed and conveyed by the suction belt 2 is separated from the downstream tension roller 5 and guided downstream in the conveyance direction. It can enter the conveyance path H formed by the member 10.

  Further, as shown in FIG. 5, the shaft 5 a of the downstream tension roller 5 is rotatably supported by the housing 20. The shaft 6 a of the upstream tension roller 6 is rotatably supported by a bearing 22 that is slidably held in the sheet conveyance direction with respect to the housing 20. The bearing 22 is urged to the upstream side in the sheet conveying direction by a spring 21. As a result, the upstream tension roller 6 is urged to the upstream side in the sheet conveying direction, and tension is applied to the suction belt 2.

  As shown in FIGS. 29 and 30, the adsorption separation unit 110 is provided with brackets 12 at both ends in the belt width direction for holding the adsorption belt 2 in a swingable manner. Each bracket 12 is rotatably supported by a support shaft 14 provided on the upstream side in the sheet conveying direction from the upstream tension roller 6. Thereby, the adsorption separation unit 110 conveys the adsorption position where the uppermost sheet 1a of the sheet bundle 1 is adsorbed by the adsorption belt 2 and the uppermost sheet 1a adsorbed by the adsorption belt 2 by the swing mechanism 120 described later. Can be swung around the support shaft 14 as a fulcrum.

  The upstream tension roller 6 and the downstream tension roller 5 are held by each bracket so as to be movable in the direction perpendicular to the upper surface of the sheet bundle. Specifically, each bracket 12 has two elongated holes, the shaft 6a of the upstream tension roller 6 passes through the elongated hole 12a, and the downstream tension roller passes through the elongated hole 45. 5 shaft 5a penetrates. Further, the downstream tension roller 5 is urged toward the sheet bundle side by a spring 46. As shown in FIG. 30, when the adsorption separation unit 110 is in the feeding position, the shaft 6a of the upstream stretching roller 6 abuts against the lower end 41 of the long hole 12a, and the shaft 5a of the downstream stretching roller 5 Is in contact with the lower end of the long hole 45.

  The lower end 41 of the long hole 12a with which the upstream tension roller abuts is provided closer to the sheet bundle 1 than the lower end of the long hole 45 with which the downstream tension roller 5 abuts. In addition, the long hole 12 a provided in the bracket 12 has an arc shape centered on the rotation center of the downstream tension roller 5 that contacts the lower end of the long hole 45. This is so that the distance between the rotation center of the upstream tension roller 6 and the rotation center of the downstream tension roller 5 does not change even if the shaft 6a of the upstream tension roller 6 moves in the long hole 12a. It is to do. As a result, the tension of the suction belt 2 does not change when the suction separation unit swings between the suction position and the feeding position.

  Usually, even when the tension of the suction belt 2 is 5 [N] or less, the suction belt 2 can be driven to rotate and the sheet adsorbed on the suction belt 2 can be conveyed without slipping between the rollers. is there. However, when a sheet having a special condition such as a sheet having high adhesion is conveyed, a slip may occur between the suction belt 2 and the roller. For this reason, it is preferable that the friction coefficient of the surface of the upstream tension roller 6 or the surface of the downstream tension roller 5 is increased to make it difficult to cause slip.

  As shown in FIG. 7, a driven first pulley 26a and a driving second pulley 26b are fixed to one end of a support shaft 14 that rotatably supports each bracket 12. A driven second pulley 25 is fixed to one end of the downstream tension roller 5, and a driven timing belt 28 is wound around the driven first pulley 26 a and the driven second pulley 25. A drive motor 24 is provided upstream of the support shaft 14 in the sheet conveying direction, and a drive first pulley 27 is fixed to the motor shaft of the drive motor 24. A drive timing belt 29 is wound around the drive first pulley 27 and the drive second pulley 26b.

  When the drive motor 24 is driven, the downstream tension roller 5 is rotationally driven via the drive timing belt 29 and the driven timing belt 28. As a result, the suction belt 2 is rotationally driven, and the upstream tension roller 6 is driven to rotate by friction of the inner surface of the suction belt 2. In the present embodiment, the driving force of the driving motor 24 is transmitted to the downstream tension roller 5 through the support shaft 14 that supports the bracket 12. With this configuration, as will be described later, the adsorption / separation unit 110 swings with the support shaft 14 as a fulcrum, so that even if the adsorption / separation unit 110 swings, it supports the downstream tension roller 5. The distance from the shaft 14 does not vary. Therefore, the tension of the driven timing belt 28 is maintained and the driving force can be transmitted to the downstream tension roller 5 satisfactorily.

  Further, as shown in FIGS. 29 and 30, a swing mechanism 120 as a swinging means for swinging the bracket 12 is provided on the downstream side in the sheet conveying direction. The swing mechanism 120 has a rack gear portion 13 as a first drive transmission portion formed at a downstream end portion of each bracket 12 in the sheet conveyance direction, and a second drive transmission fixed to the rotary shaft 16 and meshing with the rack gear portion 13. And a pinion gear 15 as a member. The swing mechanism 120 includes a swing motor 30. At one end of the rotary shaft 16, a driven gear 32 that meshes with a motor gear fixed to the motor shaft of the swing motor 30 is provided.

  By fixing each pinion gear 15 to the rotating shaft 16, each pinion gear 15 can be rotated by rotating the rotating shaft 16 by the swing motor 30. Thereby, the pinion gear 15 provided at both ends in the belt width direction can be rotationally driven by one swing motor 30, the number of parts can be reduced, and the apparatus can be made inexpensive. In addition, with a simple configuration, it is possible to synchronize the drive of the rack and pinion provided at both ends in the belt width direction.

  The rack gear portion 13 has an R shape centered on the support shaft 14. The rack gear portion 13 formed on the bracket 12 swings around the support shaft 14 when the adsorption separation unit 110 swings. Therefore, by making the rack gear portion 13 R-shaped around the support shaft 14, the meshing between the rack gear portion 13 and the pinion gear 15 can be maintained even when the adsorption / separation unit 110 is swung.

  Further, by forming the rack gear portion at the downstream end of the bracket 12 in the sheet conveying direction, the number of parts can be reduced and the configuration can be simplified as compared with the case where the rack gear separate from the bracket 12 is attached to the bracket 12. Can do. In addition, by providing a pinion on the device side of the rack and pinion of the swing mechanism 120, the configuration for transmitting the drive to the pinion is simplified compared to the case where the pinion is provided in the adsorption separation unit. Can do.

  By driving the swing motor 30, each pinion gear 15 rotates, and the rack gear portion 13 moves in a direction in which the rack gear portion 13 contacts and separates from the sheet bundle 1. Thereby, each bracket 12 swings around the support shaft 14 as a fulcrum.

  Each bracket 12 is connected and fixed by a reinforcing member 70. By connecting and fixing each bracket 12 with the reinforcing member 70, one bracket 12 and the other bracket 12 can be integrally swung. As a result, the suction belt 2 held by the bracket 12 when the bracket swings can be prevented from being twisted, and the uppermost sheet 1a adsorbed by the suction belt 2 can be prevented from being separated from the suction belt 2. can do.

  As shown in FIG. 9, a blade-shaped charging member 3 as a charging unit that charges the surface of the suction belt 2 is in contact with the surface of the suction belt 2. The charging member 3 is connected to a charging power source 4 that generates alternating current. By making the charging member 3 into a blade shape, the alternating charging interval can be easily reduced in pitch, and stable charging can be performed even if the adsorption belt 2 has a minute wave. In this embodiment, the blade-shaped charging member 3 is used as the charging means, but a roller-shaped electrode member 103 as shown in FIG. 8 may be used.

Next, a sheet conveying operation using the sheet conveying apparatus 200 of the present embodiment will be described with reference to FIG.
As shown in FIG. 31A, normally, the bottom plate 7 is in the lowered position, and the adsorption separation unit 110 is in the adsorption position. First, when a paper feed signal is input, the swing motor 30 is driven to rotate the pinion gear 15 in the clockwise direction in the figure, and the adsorption separation unit 110 is rotated counterclockwise in the figure with the support shaft 14 as a fulcrum (sheet). Swing in a direction away from the bundle. When the adsorption separation unit 110 swings to the feeding position, the drive of the swing motor 30 is stopped.

  When the suction separation unit 110 stops at the feeding position, the drive motor 24 is driven to move the suction belt 2 endlessly as shown in FIG. Next, an alternating voltage is applied to the suction belt 2 that moves endlessly by the charging power source 4 via the charging member 3, and a pitch (pitch is determined) on the surface of the suction belt 2 according to the AC power source frequency and the circumferential speed of the suction belt 2. 5 [mm] to 15 [mm] is preferable, and an alternating charge pattern is formed. The charging power source 4 may be an alternating current or a direct current having a high and low alternating potential, such as a rectangular wave or a sine wave. In the present embodiment, a rectangular wave having an amplitude of 4 [kV] is applied to the surface of the suction belt 2.

  When the charging of the suction belt 2 is completed, as shown in FIG. 31 (c), the rotation of the suction belt 2 is stopped and the bottom plate 7 that has been waiting at the lowered position is started to rise. Also, before and after this, the swing motor 30 is rotated in the reverse direction, the pinion gear 15 is rotated counterclockwise in the figure, and the adsorption separation unit 110 is rotated clockwise in the figure (the sheet bundle) with the support shaft 14 as a fulcrum. Rocks in a direction close to When the bottom plate 7 is raised and the suction separation unit 110 is lowered, the uppermost sheet 1a of the sheet bundle 1 comes into contact with the upstream tension roller 6 via the suction belt 2.

  Further, when the bottom plate 7 is raised and the adsorption separation unit 110 is lowered, the upstream tension roller 6 is pushed up by the sheet bundle 1 and hits the lower end 41 of the long hole 12a. Moves upward while being guided by the long hole 12a. Further, as the bottom plate 7 is raised, the filler 44 rotates counterclockwise in the drawing. When the uppermost sheet 1a of the sheet bundle 1 comes to a predetermined position, the filler 44 blocks the light from the light emitting portion 43b of the transmission optical sensor 43, and the sheet detecting means 40 is the uppermost sheet 1a of the sheet bundle 1. Is detected, and the ascent of the bottom plate 7 is stopped.

  Further, when the suction separation unit 110 is further swung in the clockwise direction in the drawing (a direction close to the sheet bundle), the downstream tension roller 5 contacts the uppermost sheet 1 a of the sheet bundle 1 via the suction belt 2. Touch. From this state, the adsorption / separation unit 110 is further swung in the clockwise direction in the drawing (in the direction approaching the sheet bundle). Then, as shown in FIG. 31 (d), the downstream tension roller 5 is pushed up by the sheet bundle 1 against the urging force of the spring 46 and hits the lower end of the long hole 45. 5 moves upward while being guided by the long hole 45. Then, the rotation of the swing motor 30 is stopped, and the swing of the adsorption separation unit 110 is stopped.

  When the swing motor 30 is a stepping motor, the suction separation unit 110 can be accurately stopped at the suction position by controlling the swing motor 30 based on the rotation angle (number of pulses). When the swing motor 30 is a DC motor, the adsorption / separation unit 110 can be accurately stopped at the suction position by controlling the swing motor 30 based on the driving time.

  As shown in FIG. 31 (d), when the lowering (swinging) of the adsorption separation unit 110 stops, both the upstream tension roller 6 and the downstream tension roller 5 are separated from the lower ends of the long holes 12a and 45. The support of the tension rollers 5 and 6 is released. Each of the stretching rollers 5 and 6 is placed on the sheet bundle, and the suction belt 2 supported by the suction separation unit is supported by the sheet bundle 1. As a result, even if the position in the height direction (vertical direction in the drawing) of the uppermost sheet 1a of the sheet bundle 1 is slightly shifted or the sheet bundle 1 is inclined, the sheet bundle 1 faces the sheet bundle 1 of the suction belt 2. It is possible to reliably bring the region to be brought into contact with the uppermost sheet 1 a of the sheet bundle 1.

  When the suction belt 2 comes into contact with the uppermost sheet 1a, Maxwell's stress acts on the dielectric sheet due to an unequal electric field formed by the charge pattern on the surface of the suction belt 2, and the uppermost sheet of the sheet bundle 1 1a is adsorbed to the adsorbing belt 2.

  In the state shown in FIG. 31 (d), when the uppermost sheet 1 a is adsorbed to the adsorbing belt 2, the swing motor 30 is driven to rotate the pinion gear 15 clockwise to adsorb and separate unit 110. Is pivoted counterclockwise in the figure with the support shaft 14 as a fulcrum. Then, the downstream tension roller 5 placed on the sheet bundle hits the lower end of the long hole 45, is supported by the bracket 12, and moves together with the bracket 12 in a direction away from the sheet bundle 1.

  Since the lower end 41 of the long hole 12a is on the sheet bundle side with respect to the long hole 45, at this time, the upstream tension roller 6 does not move from the upper surface of the sheet bundle 1 due to its own weight and is relatively relative to the bracket 12. Move in the direction of sheet bundle 1. Accordingly, the suction belt 2 moves so as to swing around the rotation center of the upstream tension roller 6, and the uppermost sheet 1 a adsorbed to the suction belt 2 is stretched upstream of the suction belt 2. The portion wound around the gantry roller 6 is bent around a fulcrum. As a result, the restoring force acts on the sheet adsorbed on the adsorption belt 2, and only the uppermost sheet 1a can be adsorbed on the adsorption belt 2, and the second sheet 1b can be separated by the restoring force of the sheet.

  When the adsorption separation unit 110 further rotates counterclockwise in the drawing with the support shaft 14 as a fulcrum, the upstream tension roller 6 hits the lower end 41 of the long hole 12a. In this manner, the adsorption / separation unit 110 is further rotated from the state in which the upstream tension roller 6 is in contact with the lower end 41 of the long hole 12a. Then, the upstream tension roller 6 is also supported by the bracket 12 and moves together with the bracket 12, and the upstream tension roller 6 is separated from the upper surface of the sheet bundle 1.

  As shown in FIG. 31E, when the suction separation unit 110 reaches the feeding position for conveying the sheet, the drive of the swing motor 30 is stopped. Then, the drive motor 24 is driven to move the suction belt 2 endlessly, and the uppermost sheet 1 a sucked on the suction belt 2 is transported toward the transport roller pair 9. When the leading edge of the uppermost sheet 1a electrostatically attracted to the suction belt 2 reaches the winding portion of the downstream tension roller 5 of the suction belt 2, it is separated from the suction belt 2 by curvature separation and guided to the guide member 10. However, it moves toward the conveyance roller pair 9 (see FIG. 31E).

  The linear speeds of the conveyance roller pair 9 and the suction belt 2 are the same. When the conveyance roller pair 9 is intermittently driven at a timing, the drive motor 24 is driven so that the adsorption belt 2 is also intermittently driven. To control. Alternatively, the drive of the suction belt 2 may be controlled by providing an electromagnetic clutch in the drive mechanism 130 and controlling the electromagnetic clutch.

  Further, the suction belt 2 is charged by the length of the conveying roller pair 9 from the sheet separation position of the suction belt 2, and thereafter, the suction belt 2 is neutralized by the charging member 3. Also good. Thus, after the sheet is conveyed to the conveying roller pair 9, the sheet is conveyed only by the conveying force of the conveying roller pair 9 without being affected by the suction belt 2. Further, by neutralizing the suction belt 2, it is possible to suppress the second sheet 1 b from being electrostatically attracted to the separated suction belt 2.

  In the present embodiment, as described above, the uppermost sheet 1a of the sheet bundle 1 can be sucked to the suction belt 2 while the suction belt 2 is supported on the upper surface of the sheet bundle. Thereby, even if the position of the uppermost sheet 1a in the height direction is slightly shifted or the sheet bundle 1 is inclined, the region facing the sheet bundle 1 of the suction belt 2 is surely different from the uppermost sheet 1a. The uppermost sheet 1a can be adsorbed to the adsorption belt 2 in the contact state. As a result, the uppermost sheet 1a can be reliably adsorbed to the adsorption belt 2.

  Further, in the present embodiment, the downstream tension roller 5 is urged toward the sheet bundle 1 by the spring 46, and therefore, the downstream tension roller 5 is moved to the uppermost sheet 1a of the sheet bundle 1 with a predetermined pressure. It can be made to contact. Therefore, the uppermost sheet 1a can be adsorbed to the adsorption belt 2 more reliably.

  Usually, the suction separation unit 110 is swung clockwise (in the sheet bundle side) by a predetermined amount from the position where the region of the suction belt 2 facing the sheet bundle 1 contacts the uppermost sheet 1a. The region of the suction belt 2 can be brought into contact with the uppermost sheet 1a. Thereby, a means for detecting that the region of the suction belt 2 is in contact with the uppermost sheet 1a is provided, and it is easy to control the swing of the suction separation unit based on the detection result of the detection means. The region of the suction belt 2 can be brought into contact with the uppermost sheet 1a by control. Therefore, the number of parts of the sheet conveying apparatus 200 can be reduced, the cost of the sheet conveying apparatus 200 can be reduced, and the swing control can be simplified.

  Further, in the present embodiment, the long hole 45 is provided in the bracket 12 and the shaft 5a of the downstream tension roller 5 is held in the long hole 45. However, the present invention is not limited to this. When the downstream tension roller 5 is separated from the upper surface of the sheet bundle 1, the shaft 5 a of the downstream tension roller 5 is supported, and the downstream tension roller 5 is in the sheet bundle with respect to the bracket 12. Any structure can be used as long as it can move in the vertical direction of the upper surface of the substrate. Further, the configuration in which the upstream tension roller 6 is supported by the bracket 12 so as to be movable is not limited to the long hole 12a. The upstream tension roller 6 is held with respect to the bracket 12 so as to be swingable about the downstream tension roller 5. In addition, when the suction separation unit 110 is at the feeding position, the upstream tension roller 6 may be supported so that the inclination angle of the suction belt 2 with respect to the upper surface of the sheet bundle is a predetermined angle.

  In the present embodiment, the uppermost sheet is electrostatically adsorbed to the adsorption belt 2 and the uppermost sheet is separated from the second sheet. Therefore, as in the separation method using the frictional force, the sheet friction Double feed does not occur due to the influence of the coefficient.

  Further, in the present embodiment, the adsorption separation unit 110 is swung by the meshing of the pinion gear 15 and the rack gear portion 13. Thereby, both the swing from the suction position to the feeding position and the swing from the feeding position to the suction position can be performed by the driving force of the swing motor 30. Therefore, the adsorption separation unit can be lowered to the adsorption position faster than the free fall speed of the adsorption separation unit 110. Therefore, after the first sheet is conveyed, the suction operation for the next sheet can be started quickly, and the sheet interval can be shortened. Thereby, productivity can be improved.

  Further, when the suction separation unit 110 is swung to the suction position, the suction belt 2 is supported by the sheet bundle 1, so that it is not necessary to accurately control the stop position at the suction position. Furthermore, each time a sheet is transported, the area facing the upper surface of the sheet bundle 1 of the suction belt 2 does not move up the bottom plate or the suction position of the suction separation unit is changed. It can be brought into contact with the upper sheet.

  Further, in this embodiment, the swing mechanism 120 is provided on the downstream side in the sheet conveying direction away from the support shaft 14 that is the swing support point of the adsorption separation unit 110. As a result, the downstream side in the sheet conveyance direction of the adsorption separation unit 110 can be supported by the engagement of the pinion gear 15 and the rack gear portion 13. As a result, the adsorption / separation unit 110 is supported at both ends by the support shaft 14 and the swing mechanism 120, and vibration of the adsorption / separation unit 110 can be suppressed compared to the case where the adsorption / separation unit 110 is cantilevered. it can. Thereby, it is possible to prevent the uppermost sheet 1a adsorbed to the adsorption belt 2 from being separated from the adsorption belt 2 due to the vibration of the adsorption separation unit 110.

  In addition, the driving force is transmitted to the adsorption separation unit 110 at the end on the downstream side in the sheet conveying direction farthest from the support shaft 14, which is the fulcrum of the adsorption separation unit 110, and the adsorption separation unit 110 is oscillated. Yes. In this way, by separating the portion where the driving force is transmitted from the support shaft 14, the distance from the fulcrum of swing to the meshing portion (the force point in the lever principle) is set to the center of gravity of the adsorption separation unit (the effect in the lever principle) The distance from the point) to the fulcrum can be longer. Thereby, the adsorption separation unit 110 can be swung with a smaller load than when the driving force is transmitted on the support shaft side (upstream side in the sheet conveyance direction of the adsorption separation unit 110). Therefore, the enlargement of the swing motor 30 can be avoided, and the enlargement of the apparatus can be suppressed. Further, it is possible to suppress wear of the meshing portion between the pinion gear 15 and the rack gear portion 13.

  Further, by providing the rack gear portion 13 and the pinion gear 15 at both ends in the belt width direction, both ends in the belt width direction of the adsorption separation unit 110 are supported by the meshing of the rack gear portion 13 and the pinion gear 15. Thereby, the twist of the adsorption separation unit 110 can be suppressed.

  The swing mechanism 120 is not limited to the above configuration, and the adsorption separation unit 110 may be swung by fixing the rack gear and the bracket 12 to the support shaft 14 and rotating the support shaft 14. Moreover, you may comprise the rocking | fluctuation mechanism 120 with the wire engaged with the downstream edge part of the bracket 12, and the winding device which winds up this wire.

  In the present embodiment, the downstream tension roller 5 is urged toward the sheet bundle 1 by the spring 46, but the spring 46 may not be provided as shown in FIG. As shown in FIG. 32, even in the configuration in which the spring 46 is eliminated, when the suction separation unit 110 is in the suction position, the suction belt 2 is supported by the sheet bundle 1 and faces the sheet bundle 1 of the suction belt 2. Can be reliably brought into contact with the uppermost sheet of the sheet bundle 1.

  Further, as shown in FIG. 33, the long hole 45 may be formed in an arc shape centering on the support shaft 14 that is a fulcrum of swinging of the adsorption separation unit 110. In this way, by forming the long hole 45 in an arc shape, when the downstream tension roller 5 contacts the sheet bundle and moves relative to the bracket 12 in a direction away from the sheet bundle, the long hole 45 The long hole 45 can be smoothly moved without the shaft 5 a being caught by the 45.

  Further, even if the bracket 12 is swung clockwise in the drawing from the state in which the downstream tension roller 5 is in contact with the uppermost sheet 1a of the sheet bundle 1, the shaft 5a remains on the short side of the long hole. The position of the downstream tension roller 5 in the sheet conveying direction is not changed by being pushed by the surface. As a result, the positional relationship between the shaft 5a of the downstream tension roller and the support shaft 14 can be maintained constant, and the driven timing belt 28 does not bend or extend.

  As shown in FIG. 34, the long hole 45 may be tilted so that the upper end of the long hole 45 is on the upstream side in the sheet conveying direction with respect to the lower end. Thereby, the contact point between the shaft 5 a of the downstream tension roller and the lower end of the long hole 45 is on the downstream side of the center of the downstream tension roller 5. Since the shaft 5a of the downstream tension roller is biased toward the lower end of the long hole 45, when the adsorption separation unit 110 swings from the feeding position to the adsorption position, the downstream tension roller 5 is The spring is biased toward the downstream side in the sheet conveying direction.

  Due to the swinging of the adsorption / separation unit, centrifugal force is applied to the downstream tension roller 5, and the downstream tension roller 5 tends to move downstream in the sheet conveying direction. However, since the downstream tension roller 5 is already abutted against the lower end of the long hole 45 on the downstream side in the sheet conveying direction from the center of the downstream tension roller 5 by the spring, it does not move. As a result, the downstream tension roller 5 is in contact with the sheet bundle and the downstream tension roller 5 is released from the support to the bracket 12 and the centrifugal force applied to the downstream tension roller disappears. , It does not move upstream in the sheet conveying direction. Thereby, it can suppress that a vibration arises in the downstream tension roller 5. FIG.

  Further, as shown in FIG. 35, when the suction separation unit 110 is stopped at the suction position, the long hole 45 may extend in a direction perpendicular to the sheet bundle. With this configuration, the downstream tension roller 5 is urged straightly by the spring 46 to the upper surface of the sheet bundle 1 in the vertical direction, and the spring 46 favorably attaches the suction belt 2 to the sheet bundle side. The uppermost sheet 1a can be satisfactorily adsorbed to the adsorption belt 2.

  Further, in the sheet conveying apparatus 200 according to the present embodiment, the various configurations of the sheet conveying apparatus 200 described in the first embodiment are appropriately adopted for the configuration other than that for urging the downstream tension roller 5 with the spring 46 described above. can do.

  Also in the sheet conveying apparatus 200 of the present embodiment, as described with reference to FIG. 1 in the first embodiment, the pressing member 35A and the pressing member 35B that press the suction belt 2 toward the sheet bundle 1 at the suction position are sucked. It is provided inside the belt 2 along the sheet conveying direction. Thereby, the pressing area of the suction belt 2 by the pressing member 35A and the pressing member 35B can be increased in the sheet conveying direction as compared with the case where one roller member is provided as a conventional pressing member. Therefore, the contact area between the suction belt 2 and the uppermost sheet 1a in the sheet conveying direction can be secured more than when only one pressing member and roller member are provided. Adsorbability can be increased.

  Further, the pressing force of the pressing member 35B is larger than the pressing force of the pressing member 35A, and the pressing force of the pressing member 35A is set to be not less than the stiffness of thin paper and not more than the stiffness of thick paper. Further, the pressing force of the pressing member 35B is larger than the stiffness of the cardboard. Thereby, when the uppermost sheet 1a is thin paper, the bending point of the uppermost sheet 1a becomes a position pressed by the pressing member 35A, and the uppermost sheet 1a is bent by the pressing member 35A. Therefore, the uppermost sheet 1a, which is a thin paper, can be tightly bent by the pressing member 35A, and the separability of the uppermost sheet 1a with respect to the sheet bundle 1 can be improved. When the uppermost sheet 1a is thin paper, even if the uppermost sheet 1a is bent tightly by the pressing member 35A, the uppermost sheet 1a is difficult to peel off from the suction belt 2 because the stiffness of the sheet is weak.

  On the other hand, when the uppermost sheet 1a is thick paper, the stiffness of the uppermost sheet 1a wins against the pressing force from the pressing member 35A, and the uppermost sheet 1a resists bending by the pressing member 35A, and the uppermost sheet 1a is bent. The point is a position pressed by the pressing member 35B. Thereby, the uppermost sheet 1a, which is a thick paper, is gently bent by the pressing member 35B, so that the uppermost sheet 1a, which is a thick paper, can be prevented from being bent and peeled off from the suction belt 2. Further, when the uppermost sheet 1a is thick paper, even if the uppermost sheet 1a is gently bent by the pressing member 35B, the uppermost sheet 1a can be separated from the sheet bundle 1 by the stiffness of the sheets.

  In addition, the contact surface 35Af and the contact surface 35Bf of the pressing member 35A and the pressing member 35B with the suction belt 2 have a curved surface shape, and the curvature of the contact surface 35Bf of the pressing member 35B is determined by the contact surface 35Af of the pressing member 35A. You may employ | adopt the structure made smaller than a curvature. In other words, the curvature radius of the contact surface 35Bf of the pressing member 35B is made larger than the curvature radius of the contact surface 35Af of the pressing member 35A.

  By setting the radius of curvature of the contact surface 35Bf of the pressing member 35B to be large, the curvature of the uppermost sheet 1a bent by the pressing member 35B can be set gently. Therefore, when the uppermost sheet 1a is thick paper, the uppermost sheet 1a can be further prevented from being bent tightly by the pressing member 35B, and the uppermost sheet 1a can be further prevented from peeling off from the suction belt 2.

  On the other hand, when the uppermost sheet 1a is thin paper, the uppermost sheet 1a is bent by the pressing member 35A. Therefore, there is no difference in the influence of the separability and the adsorptivity due to the radius of curvature of the contact surface 35Bf of the pressing member 35B. In this embodiment, since the radius of curvature of the contact surface 35Af of the pressing member 35A is smaller than that of the pressing member 35B, the uppermost sheet 1a that is a thin paper can be bent more tightly by the pressing member 35A, and the uppermost sheet with respect to the sheet bundle 1 can be bent. The separability of the sheet 1a can be further improved.

What has been described above is merely an example, and the present invention has a specific effect for each of the following modes.
(Aspect A)
A suction belt such as an endless suction belt 2 disposed on the upper surface of a sheet bundle such as the stacked sheet bundle 1; a first tension roller such as a downstream tension roller 5 that stretches the suction belt; An adsorption / separation unit such as an adsorption / separation unit 110 having a second tension roller such as the upstream tension roller 6 positioned on the upstream side in the sheet conveying direction of the first tension roller, and a charging member for charging the surface of the adsorption belt 3 and the like, an adsorption position for adsorbing the uppermost sheet such as the uppermost sheet 1a of the sheet bundle to the adsorption belt, and conveying the uppermost sheet adsorbed to the adsorption belt to the sheet bundle rather than the adsorption position In a sheet conveying apparatus such as a sheet conveying apparatus 200 provided with a contacting / separating means such as a swing mechanism 120 that contacts and separates the suction belt and the sheet bundle between the spaced positions. Pressing member 35A for pressing the suction belt toward the sheet bundle, the pressing member such as 35B, and a plurality along the sheet conveying direction inside the suction belt. According to this, as described in the above embodiment, the adsorptivity between the suction belt and the sheet can be improved.
(Aspect B)
In (Aspect A), as the contact / separation means, the suction between the suction position and the separation position is centered on a swing fulcrum such as the support shaft 14 provided on the upstream side of the second stretching roller in the sheet conveying direction. It has suction separation unit swinging means such as a swinging mechanism 120 for swinging the separation unit, and each pressing member is configured to press the suction belt with different pressing force, and upstream in the sheet conveying direction The pressing force is larger in the pressing member. According to this, as described in the above embodiment, repeated separation can be performed in response to sheet characteristics.
(Aspect C)
In (Aspect B), the contact surface of each pressing member with the suction belt has a curved surface shape, and the curvature of the curved surface shape is smaller as the pressing member is on the upstream side in the sheet conveying direction. According to this, as described in the above embodiment, the cardboard can be prevented from being bent tightly and peeled off from the suction belt.
(Aspect D)
In (Aspect B) or (Aspect C), the adsorption / separation unit swinging means includes a first drive transmission unit attached to the downstream end of the adsorption / separation unit in the sheet conveying direction, and the first drive attachment unit attached to the apparatus main body. A second drive transmission unit that meshes with the drive transmission unit is provided, and the adsorption / separation unit is swung by the engagement of the first drive transmission unit and the second drive transmission unit. According to this, as described in the above embodiment, the adsorption separation unit can be supported at both ends when the adsorption separation unit swings, and the vibration of the adsorption separation unit can be suppressed. In addition, since the meshing position of the first drive transmission unit and the second drive transmission unit can be separated from the swing fulcrum of the adsorption / separation unit, the load on the adsorption / separation unit swinging unit can be reduced. Thereby, the enlargement of the swing motor included in the adsorption separation unit swinging unit can be avoided, and wear of the meshing portion between the first drive transmission unit and the second drive transmission unit can be suppressed.
(Aspect E)
In (Aspect D), the adsorption separation unit supports the second stretching roller so as to be movable in a predetermined range vertical direction with respect to the upper surface of the sheet bundle. According to this, as described in the above embodiment, separation using the restoring force of the sheet can be performed, and good separation performance can be obtained. Further, the suction belt can be separated from the upper surface of the sheet bundle only by swinging the suction separation unit.
(Aspect F)
In (Espect E), the adsorption separation unit includes a bracket such as a bracket 12 that rotatably supports the first stretching roller and the second stretching roller, and the bracket is disposed at the downstream end portion in the sheet conveying direction of the bracket. A first drive transmission unit was formed. According to this, as described in the above embodiment, the number of parts can be reduced and the cost of the apparatus can be reduced as compared with the case where the bracket and the first drive transmission unit are configured as separate members. it can. Further, the weight of the adsorption / separation unit can be reduced, and the load when the adsorption / separation unit is swung can be reduced. Further, the inertia of the adsorption / separation unit can be weakened, and the elastic vibration when the adsorption / separation unit is stopped at the feeding position can be suppressed.
(Aspect G)
In (Aspect A), (Aspect B), (Aspect C), (Aspect D), (Aspect E), or (Aspect F), the adsorption separation unit includes a first tension roller and a second tension roller. The first and second stretching rollers are supported so that the support of the first and second stretching rollers is released when they come into contact with the uppermost sheet of the bundle via the suction belt. And an urging means for urging the first stretching roller toward the sheet bundle side. According to this, as described in the above embodiment, it is possible to increase the contact pressure of the suction belt with respect to the uppermost sheet of the sheet bundle as compared with the case where the suction belt makes contact with its own weight. Thereby, the uppermost sheet can be favorably adsorbed to the adsorption belt.
(Aspect H)
In (Aspect G), when the suction belt is in the suction position, the biasing direction of the biasing unit with respect to the first stretching roller is configured to be perpendicular to the upper surface of the sheet bundle. According to this, as described in the above embodiment, the contact pressure of the suction belt with respect to the uppermost sheet of the sheet bundle can be most efficiently increased, and the uppermost sheet can be satisfactorily attracted to the suction belt. it can.
(Aspect I)
In (Aspect H), the urging means urges the first stretching roller toward the sheet bundle side and the downstream side in the sheet conveying direction. According to this, as described in the above embodiment, it is possible to suppress the vibration in the sheet conveying direction of the first stretching roller when the first stretching roller comes into contact with the uppermost sheet of the sheet bundle. .
(Aspect J)
An image forming apparatus comprising: an image forming unit such as an image forming unit 50 that forms an image on a sheet; and a sheet conveying unit that separates the uppermost sheet from the stacked sheet bundle and conveys the uppermost sheet to the image forming unit In the above, as the sheet conveying means, (Aspect A), (Aspect B), (Aspect C), (Aspect D), (Aspect E), (Aspect F), (Aspect G), (Aspect H) or (Aspect) I) a sheet conveying apparatus. According to this, good sheet conveyance can be performed as described in the above embodiment.

DESCRIPTION OF SYMBOLS 1 Sheet bundle 1a Top sheet 1b 2nd sheet 2 Adsorption belt 3 Charging member 4 Charging power source 5 Downstream tension roller 5a Shaft 6 Upstream tension roller 6a Shaft 7 Bottom plate 8 Support member 9 Conveying roller pair 10 Guide member 11 Paper feed cassette 12 Bracket 12a Long hole 12b Long hole 12c Long hole 13 Rack gear part 14 Support shaft 15 Pinion gear 16 Rotating shaft 20 Housing 20a Housing body part 20b Shaft hole part 20c Fixing screw 21 Spring 22 Bearing 23 Rib 24 Drive motor 24a Motor Shaft 25 Driven second pulley 26a Driven first pulley 26b Driven second pulley 27 Driven first pulley 28 Driven timing belt 29 Driven timing belt 30 Swing motor 30a Motor shaft 31 Motor gear 32 Driven gear 35A Press member 35Aa Press part Main body portion 35Ab Holding portion 35Ac Compression spring installation portion 35Ad Shaft hole portion 35Ae Fixing screw 35Af Contact surface 35B Press member 35Ba Press member main body portion 35Bb Holding portion 35Bc Compression spring installation portion 35Bd Shaft hole portion 35Be Fixing screw 35Bf Contact surface 36Bf Spring 36B Compression spring 40 Sheet detection means 41 Lower end 41a Lower end surface 41b Lower end surface 41c Lower end surface 42 Shaft 43a Light receiving portion 43b Light emitting portion 43 Transmission type optical sensor 44 Filler 45 Long hole 46 Spring 47 Driven pulley 48 Timing belt 49 Timing belt 50 Image Forming unit 52 Paper feeding unit 53 Registration roller 54 Transfer device 55 Fixing device 56 Paper discharge roller pair 57 Paper discharge tray 58 Document reading unit 59 Automatic document feeder 59a Document tray 61 Photoconductor 6 Charging device 63 Laser beam 64 Developing device 65 Photoconductor cleaning device 70 Reinforcement member 100 Copier 103 Electrode member 110 Adsorption / separation unit 120 Swing mechanism 130 Drive mechanism 145 Pinion gear 145a Pulley section 146 Rack gear 200 Sheet conveying device 200A Sheet conveying device 200B Sheet Conveying device 200C Sheet conveying device 310 Drive pulley

Japanese Patent No. 3862577

Claims (9)

An endless suction belt disposed opposite to the upper surface of the stacked sheet bundle, a first tension roller that stretches the suction belt, and a second tension roller located upstream of the first tension roller in the sheet conveying direction. An adsorption separation unit having a tension roller;
Charging means for charging the surface of the adsorption belt;
Between an adsorption position for adsorbing the uppermost sheet of the sheet bundle to the adsorbing belt and a separating position for conveying the uppermost sheet adsorbed on the adsorbing belt and separated from the sheet bundle than the adsorption position In the sheet conveying apparatus provided with contact and separation means for contacting and separating the suction belt and the sheet bundle,
A plurality of pressing members that press the suction belt toward the sheet bundle are provided along the sheet conveyance direction inside the suction belt ;
As the contact / separation means, an adsorption that swings the adsorption / separation unit between the adsorption position and the separation position around a rocking fulcrum provided on the upstream side in the sheet conveying direction from the second stretching roller. A separation unit swinging means,
Each of the pressing members is configured to press the suction belt with a different pressing force, and the pressing member on the upstream side in the sheet conveying direction has a larger pressing force . In the sheet conveying apparatus according to claim 1 ,
The contact surface of each pressing member with the suction belt has a curved surface shape, and the curvature of the curved surface shape is smaller as the pressing member is on the upstream side in the sheet conveying direction. In the sheet conveying apparatus according to claim 1 or 2 ,
The adsorption / separation unit swinging means includes a first drive transmission unit attached to the downstream end of the adsorption / separation unit in the sheet conveying direction and a second drive transmission meshing with the first drive transmission unit attached to the apparatus main body. A sheet conveying device, wherein the adsorption / separation unit is swung by meshing between the first drive transmission unit and the second drive transmission unit. In the sheet conveying apparatus according to claim 3 ,
The adsorbing and separating unit supports the second stretching roller so as to be movable in a predetermined range perpendicular direction to the upper surface of the sheet bundle. In the sheet conveying apparatus according to claim 4 ,
The adsorption separation unit includes a bracket that rotatably supports the first stretching roller and the second stretching roller, and the first drive transmission unit is provided at a downstream end of the bracket in the sheet conveying direction. A sheet conveying device formed. In the sheet conveying apparatus according to claim 1, 2, 3, 4 or 5 ,
When the first and second stretching rollers abut on the uppermost sheet of the sheet bundle via the suction belt, the suction and separation unit includes the first and second stretching rollers. The first stretching roller and the second stretching roller are supported so that the support of the stretching roller is released, and biasing means for biasing the first stretching roller to the sheet bundle side is provided. A sheet conveying apparatus.   An endless suction belt disposed opposite to the upper surface of the stacked sheet bundle, a first tension roller that stretches the suction belt, and a second tension roller located upstream of the first tension roller in the sheet conveying direction. An adsorption separation unit having a tension roller;
Charging means for charging the surface of the adsorption belt;
Between an adsorption position for adsorbing the uppermost sheet of the sheet bundle to the adsorbing belt and a separating position for conveying the uppermost sheet adsorbed on the adsorbing belt and separated from the sheet bundle than the adsorption position In the sheet conveying apparatus provided with contact and separation means for contacting and separating the suction belt and the sheet bundle,
A plurality of pressing members that press the suction belt toward the sheet bundle are provided along the sheet conveyance direction inside the suction belt;
When the first and second stretching rollers abut on the uppermost sheet of the sheet bundle via the suction belt, the suction and separation unit includes the first and second stretching rollers. The first stretching roller and the second stretching roller are supported so that the support of the stretching roller is released, and biasing means for biasing the first stretching roller to the sheet bundle side is provided. A sheet conveying apparatus. In the sheet conveying apparatus according to claim 6 or 7 ,
A sheet conveying apparatus, wherein the urging direction of the urging unit with respect to the first stretching roller is perpendicular to the upper surface of the sheet bundle when the adsorption belt is in the adsorption position. . Image forming means for forming an image on a sheet over preparative,
In an image forming apparatus comprising: a sheet conveying unit that separates the uppermost sheet from the stacked sheet bundle and conveys the uppermost sheet to the image forming unit;
As the sheet conveying means, the image forming apparatus characterized by having a sheet conveying apparatus according to claim 3, 4, 5, 6, 7 or 8.

Images