JP2014213958A - Sheet carrying device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet carrying device and an image forming apparatus capable of implementing excellent sheet separability without depending on the sheet rigidity and also capable of increasing productivity.SOLUTION: A pressing member 80 is provided, which, when a suction separation unit is transferred from a suction position to a carrying position, presses a suction belt 2 against a sheet bundle 1 at a position on downstream, in a sheet carrying direction, of an upstream side hanging roller 6 within a suction area of the suction belt to which the uppermost sheet 1a of the sheet bundle is sucked. The pressing member 80 separates from the sheet bundle 1 together with the suction belt 2 when an inclination angle at which the suction belt 2, on downstream of the pressing position in the sheet carrying direction, inclines with respect to the sheet bundle 1, becomes a predetermined angle in step with the transfer. The inclination angle when the pressing member 80 is separated from the sheet bundle 1 is configured to be changeable.

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 of separating and transporting stacked sheets such as originals and recording paper in a sheet conveying apparatus used in an image forming apparatus, an electrostatic field is formed by forming an electric field on an adsorption belt and bringing it into contact with the sheet for adsorption and separation. Electroadsorption separation systems have been proposed.

  An electrostatic adsorption separation type sheet conveyance device described in Patent Document 1 includes a dielectric adsorption belt wound around two rollers, and a charge applying unit as an adsorption unit that applies alternating charges to the adsorption belt. And an adsorption / separation unit composed of a holder for holding them. The holder rotatably supports the two rollers, and is fixed to a rotation shaft provided upstream of the two 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.

  Of the two rollers, the upstream roller disposed on the upstream side in the sheet conveying direction is supported by the holder as follows. That is, when the suction separation unit is moved from the suction position to the transport position, it keeps contacting the upper surface of the sheet bundle until the suction separation unit swings by a predetermined angle, and when the suction separation unit swings by a predetermined angle or more, it is separated from the sheet bundle together with the holder. The holder is supported by the holder so as to be movable within a predetermined range. On the other hand, the downstream roller disposed on the downstream side in the sheet conveying direction is supported by the holder as follows. That is, when the suction separation unit is moved from the suction position to the transport position, the holder is supported by the holder so as to start separating from the sheet bundle together with the holder from the beginning of the movement.

  In the previous stage of paper feeding, the suction belt held by the holder via the two rollers is located at a position away from the sheet bundle. When separating and transporting the uppermost sheet of the sheet bundle, first, the suction belt is rotated to apply an alternating charge to the suction belt. After applying the alternating charge to the suction belt, stop the rotation of the suction belt, drive the swing mechanism to swing the suction separation unit to the sheet bundle side, bring the suction belt into contact with the uppermost sheet of the sheet bundle, and Adhere the uppermost sheet of the bundle to the adsorption belt. At this time, the upstream tension roller is released from support with the holder and is placed on the upper surface of the sheet bundle.

  When the uppermost sheet of the sheet bundle is attracted to the suction belt on the surface portion of the suction belt brought into contact with the upper surface of the sheet bundle, the swing mechanism is driven to swing the suction separation unit from the suction position toward the transport position. When swinging from the suction position to the transport position is started, the downstream roller moves together with the holder in a direction away from the sheet bundle. On the other hand, the upstream roller does not move from the upper surface of the sheet bundle with the suction belt sandwiched by its own weight. Accordingly, the surface portion of the suction belt on the downstream side in the sheet conveying direction with respect to the upstream roller is inclined with respect to the upper surface of the sheet bundle, and the surface pressed by the upstream roller with the suction belt interposed therebetween is used as the fulcrum. The portion of the uppermost sheet adsorbed on the portion is lifted while being bent. Thereafter, the upstream roller is lifted by the holder, the upstream roller moves together with the holder, is separated from the upper surface of the sheet bundle, and reaches the conveyance position. When the adsorption separation unit reaches the conveyance position, the adsorption belt is driven to rotate, and the uppermost sheet adsorbed on the adsorption belt is conveyed.

  The second sheet that is in close contact with the uppermost sheet by the adhesion force is separated by its own stiffness by being bent with the portion pressed by the upstream roller sandwiching the suction belt. The inclination angle between the surface portion of the suction belt on the downstream side in the sheet conveying direction and the upper surface of the sheet bundle with respect to the upstream roller at the time of separation varies depending on the rigidity of the sheet. A sheet with strong stiffness and high rigidity separates at a small inclination angle, but a sheet with low rigidity and low rigidity does not separate unless the inclination angle is large. If a large inclination angle that separates the low rigidity sheet is used even in the strong rigidity sheet, even the uppermost sheet is peeled off from the suction belt by its own elasticity.

  For this reason, in the sheet conveying apparatus described in Patent Document 1, the inclination angle of the suction belt with respect to the upper surface of the sheet bundle when the upstream roller is separated from the sheet bundle is made different according to the rigidity of the sheet. Specifically, it has means for changing the range of movement of the upstream roller relative to the holder according to the rigidity of the sheet, and as the rigidity of the conveyed sheet increases, the range of movement of the upstream roller relative to the holder is reduced. Yes. Therefore, as the rigidity of the conveyed sheet increases, the upstream roller is lifted by the holder at a small inclination angle. Thereby, in a highly rigid sheet, it is possible to suppress the uppermost sheet from being peeled off from the suction belt.

  As described above, the sheet conveying device described in Patent Document 1 is good regardless of the rigidity of the sheet by changing the inclination angle of the suction belt when the upstream roller is separated from the sheet bundle according to the rigidity of the sheet. Can be obtained.

  In recent years, further improvement in productivity has been demanded, and an increase in the number of sheets conveyed per unit time has been demanded. For this reason, in the sheet conveying apparatus described in Patent Document 1, the swinging range of the adsorption belt from the adsorption position to the conveyance position is narrowed, the movement time between the adsorption position and the conveyance position is shortened, and the productivity is further improved. It is hoped that However, if the swinging range of the suction belt is narrowed, it is not possible to obtain an inclination angle that provides good separation when the sheet is low in rigidity, and there is a possibility that problems such as double feeding may occur.

  By moving the sheet bundle, it is possible to selectively take a suction position where the suction belt and the sheet bundle are in contact with each other and a transport position where the suction belt and the sheet bundle are in a separated relation. In the apparatus, the above-described problems can occur.

  The present invention has been made in view of the above background, and an object of the present invention is to provide a sheet conveying apparatus and an image forming apparatus that can obtain good separation properties and increase productivity regardless of sheet rigidity. Is to provide a device.

  In order to achieve the above object, the invention of claim 1 is directed to a rotatable endless suction belt disposed opposite to an upper surface of a stacked sheet bundle, and a first stretching roller that stretches the suction belt. A suction separation unit having a second stretching roller located upstream of the first stretching roller in the sheet conveying direction, a suction unit for sucking the uppermost sheet of the sheet bundle to the suction belt, and the sheet bundle And the suction belt are in a contact relationship, the suction position relationship for attracting the uppermost sheet of the sheet bundle to the suction belt, and the sheet bundle and the suction belt are in a spaced relationship, and the suction belt is In a sheet conveying apparatus provided with a moving means for moving at least one of the adsorption separation unit and the sheet bundle so that a conveyance positional relationship for conveying the upper sheet can be selectively taken. Thus, when shifting from the suction position relationship to the transport position relationship, the suction belt is positioned at a position downstream of the second stretching roller in the suction region where the uppermost sheet of the sheet bundle of the suction belt sucks. When the belt is pressed against the sheet bundle and the inclination angle at which the suction belt on the downstream side in the sheet conveying direction from the pressing position inclines with respect to the pressing position becomes a predetermined angle, the suction belt and the suction belt A pressing member that separates from the sheet bundle is provided, and the inclination angle when the pressing member separates from the sheet bundle can be changed.

  According to the present invention, good separability can be obtained regardless of the rigidity of the sheet, and productivity can be improved.

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. 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 an 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. The figure explaining the structure which provided the pinion gear in the bracket and provided the rack gear in the apparatus main body. FIG. 13 is a schematic configuration diagram of a drive mechanism and a swing mechanism of the sheet conveying apparatus configured as shown in FIG. 12. The figure which shows the modification of a rocking | fluctuation mechanism. The schematic block diagram which shows the sheet conveying apparatus provided with the rocking | fluctuation mechanism of the modification. The figure which shows another modification of a rocking | fluctuation mechanism with a paper feed part. The perspective view of FIG. The figure which shows another modification of a rocking | fluctuation mechanism with a paper feed part. The top view of FIG. The figure which shows the example comprised so that an upstream tension roller and a downstream tension roller may be hold | maintained to each bracket so that a vertical movement is possible with respect to the sheet bundle upper surface. FIG. 21 is a diagram illustrating a sheet conveying operation of the sheet conveying apparatus illustrated in FIG. 20. The figure which shows the 1st modification of the sheet conveying apparatus shown in FIG. The figure which shows the 2nd modification of the sheet conveying apparatus shown in FIG. The figure which shows the 3rd modification of the sheet conveying apparatus shown in FIG. The figure which shows the 4th modification of the sheet conveying apparatus shown in FIG. FIG. 3 is a schematic diagram of a sheet conveying apparatus showing a characteristic part of the present embodiment. AA sectional drawing of FIG. The figure which looked at FIG. 27 from the B direction. The schematic diagram which shows the structure of a pressing member drive mechanism. The figure explaining the sheet | seat separation operation | movement in this embodiment. The figure explaining switching of a push part. The schematic diagram which shows the structure which provided the urging member which urges | biases an upstream tension roller to the lower end side of a long hole. FIG. 3 is a schematic diagram showing an air suction type sheet conveying apparatus.

  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. 1 is a schematic diagram showing a 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.

  2 is a perspective view illustrating a schematic configuration of the paper feeding unit 52, FIG. 3 is a schematic diagram illustrating the paper feeding unit 52, and FIG. 4 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. 3, 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. 2, the sheet feeding unit 52 is provided with a sheet detecting unit 140 that detects that the uppermost sheet 1a of the sheet bundle 1 has reached a predetermined position.

  The sheet detection unit 140 includes a filler 144 that is rotatably supported by a shaft 142 provided in the apparatus main body, and a transmission optical sensor 143. 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 144. At this time, the light receiving unit 143a of the transmissive optical sensor 143 receives light from the light emitting unit 143b. Further, when the bottom plate 7 is raised, the filler 144 blocks the light of the light emitting unit 143b, and the light receiving unit 143a 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. 4, 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.

  As shown in FIG. 4, 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. 5 is an exploded view of the housing 20. One of the two shaft hole portions 20b having a shaft hole that supports 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. . The separate shaft hole portion 20b has one shaft hole portion 20b attached to the housing main body portion with a fixing screw 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. 2 and 3, 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. 3, 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 elongated hole 12a.

  The elongated hole 12a provided in the bracket 12 is provided so that the upstream tension roller 6 and the downstream tension roller 5 are rotated at the center of rotation even when the shaft 6a of the upstream tension roller 6 moves in the elongated 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.

  Usually, even if the tension of the suction belt 2 is 5 [N] or less, the suction belt 2 is driven to rotate without slipping between the downstream tension roller 5 and the upstream tension roller 6 and the suction belt 2, It is possible to convey the uppermost sheet 1a adsorbed to the adsorption belt 2.

  On the other hand, when a sheet having a special condition such as a sheet having a high adhesion force is conveyed, slip may occur between the downstream tension roller 5 and the upstream tension roller 6 and the suction belt 2. It is done. 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. 6 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. 2 and 3, 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 conveyance 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. 7, 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. 8 may be used. By making the electrode member 103 into a blade shape, it is possible to form a charge pattern having a smaller pitch width than the roller-shaped charging member 3. As a result, the adsorption force of the stacked sheet bundle to the uppermost sheet 1a increases rapidly, and the adsorption force acting on the second and subsequent sheets decreases more quickly. 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 basic sheet conveying operation using the sheet conveying apparatus 200 of the present embodiment will be described with reference to FIG.

  As shown in FIG. 9A, 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. 2) 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. 9B, when the suction separation unit 110 stops at the transport position, the drive motor 24 (see FIG. 2) 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. Then, an alternating charge pattern is formed on the surface of the suction belt 2 at a pitch (pitch should be about 5 [mm] to 15 [mm]) according to the AC power supply frequency and the circumferential speed of the suction belt 2. . 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. 9C, 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 rises, the filler 144 rotates counterclockwise in the figure. When the uppermost sheet 1a of the sheet bundle 1 comes to a predetermined position, the filler 144 blocks light from the light emitting unit 143b of the transmission optical sensor 143. Thereby, the transmission type optical sensor 143 detects that the uppermost sheet 1a of the sheet bundle 1 has reached a predetermined position, and stops raising the bottom plate 7.

  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. 9 (d), when the bottom plate 7 stops rising and the adsorption separation unit 110 stops descending (swinging), 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. 9 (d), when the uppermost sheet 1 a is adsorbed to the adsorption belt 2, the swing motor 30 is driven to rotate the pinion gear 15 in the clockwise direction, and the adsorption separation 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. As a result, the surface portion of the suction belt 2 brought into contact with the upper surface of the sheet bundle is separated from the upper surface of the sheet bundle so that the surface portion is inclined with respect to the upper surface of the sheet bundle. Thereby, the sheet is bent and the portion of the uppermost sheet 1 a adsorbed on the surface portion of the suction belt 2 is turned from the upper surface of the sheet bundle along with the swinging operation of the suction belt 2. At this time, 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 elongated hole 12a. As described above, when the suction separation unit 110 is further rotated from the state in which the upstream tension roller 6 is in contact with the lower end surface 41a of the elongated 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. 9E, when the adsorption 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. 9E).

  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.

  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.

  Further, in the present embodiment, the elongated hole 12a is provided in the bracket 12, and the shaft 6a of the upstream tension roller 6 is held in the elongated hole 12a. That is, the upstream tension roller 6 is configured to be swingable with respect to the bracket 12 around the downstream tension roller 5. Further, when the suction separation unit 110 is in the feeding position, the upstream tension roller 6 is 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. What is necessary is just to provide these two structures.

  The sheet adsorbing force due to the charge pattern acts only on the uppermost sheet 1a, and does not act on paper below the second sheet 1b. 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, 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. Therefore, 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. Thereby, 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 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. Therefore, 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, 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 pinion gear 15 and the rack gear portion 13 at the downstream end portion in the sheet conveying direction of the adsorption separation unit 110, the following advantages can be obtained. That is, as shown in FIG. 10, the meshing position K between the pinion gear 15 and the rack gear portion 13 can be provided on the downstream side in the sheet conveying direction from the center of gravity P of the adsorption separation unit 110. 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 gravity center position P due to the influence of the inertia of the adsorption / separation unit itself. It will elastically vibrate according to the distance. In addition, since the gravity center position 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. Therefore, compared with the case where it is provided on the support shaft 14 side (upstream side in the sheet conveying direction), the amount of movement of the adsorption separation unit 110 per pitch can be reduced. Thereby, 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. Thereby, 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. 11, the structure which provided the rack and pinion mechanism only in the belt width direction one end side may be sufficient.

In addition, as a rocking | fluctuation mechanism which rocks the adsorption separation unit 110, you may employ | adopt a structure as shown in FIG.12 or FIG.13. In FIG. 13, the suction belt 2 and the like are not shown.
The swing mechanism 120 shown in FIGS. 12 and 13 includes a rack and pinion in which a pinion gear 145 is provided on the bracket 12 and a rack gear 146 is provided on the apparatus main body. As shown in FIG. 13, 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 is advantageous when the amount of swinging 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 rocking is large, the rocking mechanism shown in FIGS. 12 and 13 can be used to increase the rocking speed of the adsorption separation unit 110 and increase the productivity.

  Further, the swing mechanism may be configured as shown in FIGS. That is, when the suction separation unit 110 is in the feeding position, the position P of the center of gravity of the suction separation unit 110 in the sheet conveyance direction and the meshing position K between the rack gear portion 13 and the pinion gear 15 of the swing mechanism 120 are the same position. It is the composition which becomes. In order to achieve this configuration, as shown in FIG. 15, a stepped portion is provided at the downstream end of the bracket 12 in the sheet conveying direction, and a rack gear portion 13 is formed at the stepped 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.
On the other hand, in the configuration shown in FIGS. 14 and 15, when the adsorption separation unit 110 is in the feeding position, the position P of the center of gravity of the adsorption separation unit 110 and the rack gear portion 13 of the swing mechanism 120 and the pinion gear 15 are engaged. Position K is the same position. Therefore, elastic vibration when the adsorption separation unit 110 stops at the feeding position can be most effectively suppressed, and separation of the uppermost sheet 1a from the adsorption belt 2 can be suppressed.

Furthermore, a configuration as shown in FIGS. 16 and 17 may be employed.
16 and 17, the swing mechanism for swinging the adsorption / separation unit 110 includes a bracket 112, a rotation gear 113, a rotation shaft 114, a rotation gear 115, a rotation motor 117, and the like.

  A rotation shaft 114 is provided at a position parallel to the roller shafts of the downstream tension roller 5 and the upstream tension roller 6 and opposite to the feeding direction. Then, the adsorption separation unit 110 is swung up and down by brackets 112 that rotatably support both ends of the downstream tension roller 5 and the upstream tension roller 6. A rotation gear 113 that meshes with the rotation gear 115 provided on the motor shaft 116 of the rotation motor 117 is provided at one axial end side of the rotation shaft 114. Then, the bracket 112 is rotated in the vertical direction according to the rotational drive direction of the rotary motor 117.

  Further, as shown in FIG. 18, the upstream tension roller 6 may not be moved with respect to the bracket 12, and the feeding position of the adsorption separation unit may be changed according to conditions such as the thickness of the sheet.

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 In the configuration that abuts the lower end 41 of the long hole 12a, there are the following problems. That is, there is a problem that 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 1 a may be peeled off from the suction belt 2.
On the other hand, in FIG. 18, the upstream tension roller 6 is supported so as not to move with respect to the bracket 12. Thereby, according to conditions, such as paper thickness, the rocking | fluctuation range of the adsorption separation unit 110 can be varied and the feeding position of the adsorption separation unit 110 can be varied. In this case, if the rotating shaft 16 that fixes the pinion gear 15 is within the swinging range of the adsorption separation unit 110 (the enclosed range in FIG. 18), 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. 19, 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.

  The swing mechanism 120 is not limited to the above configuration, and the swing mechanism 120 may be configured by a wire that engages with the downstream end of the bracket 12 and a winding device that winds up the wire.

  Further, as shown in FIG. 20, the upstream tension roller 6 and the downstream tension roller 5 may be configured to be held by each bracket 12 so as to be movable in a direction perpendicular to the upper surface of the sheet bundle. Specifically, as shown in FIG. 20, each bracket 12 is provided with an upstream slot 12a and a downstream slot 45. The shaft 6a of the upstream stretching roller 6 is passed through the upstream long hole 12a, and the shaft 5a of the downstream stretching roller 5 is passed through the downstream long hole 45. Further, the downstream tension roller 5 is urged toward the sheet bundle side by a spring 46. As shown in FIG. 20, when the adsorption separation unit 110 is in the feeding position, the shaft 6a of the upstream tension roller 6 abuts the lower end 41 of the upstream slot 12a, and the downstream tension roller 5 The shaft 5 a is in contact with the lower end of the downstream long hole 45. Further, the lower end 41 of the upstream elongated hole 12a against which the upstream tension roller 6 abuts is provided closer to the sheet bundle 1 than the lower end of the downstream elongated hole 45 against which the downstream tension roller 5 abuts.

FIG. 21 is a diagram illustrating the sheet conveying operation of the sheet conveying apparatus 200 illustrated in FIG.
As shown in FIG. 21 (a), the bottom plate 7 is normally in the lowered position, and the adsorption / separation unit 110 is in the adsorption position. When a paper feed signal is input, the swing motor 30 is driven and the pinion gear 15 is moved. In the drawing, it is rotated clockwise, and the adsorption separation unit 110 is swung to the feeding position.

  Next, as shown in FIG. 21B, the drive motor 24 is driven to move the suction belt 2 endlessly, and the suction belt 2 is charged. When charging is completed, as shown in FIG. 8C, 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 is in contact with the lower end 41 of the upstream slot 12a. The gantry roller 6 moves upward while being guided by the upstream slot 12a. Further, as the bottom plate 7 rises, the filler 144 rotates counterclockwise in the figure. When the uppermost sheet 1a of the sheet bundle 1 comes to a predetermined position, the filler 144 blocks the light of the light emitting part 143b of the transmission optical sensor 143, and the sheet detecting means 140 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, when the suction separation unit 110 is further swung clockwise in the drawing (in the direction approaching the sheet bundle), the downstream tension roller 5 is moved by the spring 46 as shown in FIG. The sheet bundle 1 is pushed up against the urging force. As a result, the downstream tension roller 5 that has been in contact with the lower end of the downstream elongated hole 45 moves upward while being guided by the downstream elongated hole 45. Then, the rotation of the swing motor 30 is stopped, and the swing of the adsorption separation unit 110 is stopped.

  As shown in FIG. 21D, 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. . As a result, the support of the tension rollers 5 and 6 is released, and the tension rollers 5 and 6 are put on the sheet bundle, and the suction belt 2 supported by the suction separation unit is replaced with the sheet bundle 1. It becomes the form supported by. 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, the stress of Maxwell acts on the sheet as a dielectric due to the unequal electric field formed by the charge pattern on the surface of the suction belt 2 as described above, and the sheet bundle 1 The uppermost sheet 1 a is adsorbed to the adsorption belt 2.

  Similarly to the above, the uppermost sheet 1a is adsorbed to the adsorption belt 2 after waiting for a predetermined time in the state shown in FIG. When the uppermost sheet 1a is adsorbed to the adsorption belt 2, the swing motor 30 is driven to rotate the pinion gear 15 in the clockwise direction, and the adsorption separation unit 110 is rotated counterclockwise in the figure with the support shaft 14 as a fulcrum. Rock. Then, the downstream tension roller 5 placed on the sheet bundle hits the lower end of the downstream elongated 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 upstream elongated hole 12a is closer to the sheet bundle side than the downstream elongated 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. Relatively move in the direction of the sheet bundle 1. As a result, the sheet is bent and the portion of the uppermost sheet 1a adsorbed on the surface portion of the suction belt 2 is turned from the upper surface of the sheet bundle along with the swinging operation of the adsorption belt 2, and the second sheet 1b. Are 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 elongated hole 12a. As described above, when the suction 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 elongated hole 12 a, the upstream tension roller 6 is also supported by the bracket 12. Then, it 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. 21E, 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 pair of transport rollers 9 (see FIG. 21E).

  In the sheet conveying apparatus shown in FIG. 20, the uppermost sheet 1a of the sheet bundle 1 can be adsorbed to the adsorption belt 2 in a state where the adsorption belt 2 is supported on the upper surface of the sheet bundle. 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. The area to be made can be reliably brought into contact with the uppermost sheet 1a of the sheet bundle 1. Therefore, the uppermost sheet 1a can be adsorbed to the adsorbing belt 2 in a state where the region of the adsorbing belt 2 facing the sheet bundle 1 is in contact with the uppermost sheet 1a of the sheet bundle 1 with certainty. As a result, the uppermost sheet 1a can be reliably adsorbed to the adsorption belt 2. Further, since the downstream tension roller 5 is biased toward the sheet bundle 1 by the spring 46, the downstream tension roller 5 can be brought into contact with the uppermost sheet 1a of the sheet bundle 1 with a predetermined pressure. it can. Therefore, the uppermost sheet 1a can be adsorbed to the adsorption belt 2 more reliably.

  Normally, the suction belt 2 is simply swung clockwise (in the sheet bundle side) by a predetermined amount from the position where the suction belt 2 contacts the uppermost sheet 1a of the sheet bundle 1. Can be reliably brought into contact with the uppermost sheet 1a of the sheet bundle 1. Thus, it is not necessary to provide a means for detecting that the suction belt 2 is in contact with the uppermost sheet 1a of the sheet bundle 1 and to control the swing of the suction separation unit based on the detection result of the detection means. . Accordingly, the region facing the sheet bundle 1 of the suction belt 2 can be brought into contact with the uppermost sheet 1a of the sheet bundle 1 with simple 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.

  In the above description, the downstream elongated hole 45 is provided in the bracket 12 and the shaft 5a of the downstream tension roller 5 is held in the downstream elongated hole 45. However, the following configuration may be used. That is, when 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 perpendicular to the bracket 12 with respect to the upper surface of the sheet bundle. It is a structure which can be moved to.

  In the configuration shown in FIG. 20, 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. 22, even in a 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. 23, the downstream long hole 45 may have an arc shape centering on the support shaft 14 that is a fulcrum of swinging of the adsorption / separation unit 110. Thus, the following advantages can be acquired by making the downstream long hole 45 circular arc shape. That is, when the downstream tension roller 5 contacts the sheet bundle and moves in a direction away from the sheet bundle relative to the bracket 12, the shaft 5 a is not caught in the downstream long hole 45. Therefore, the shaft 5a can be smoothly moved to the downstream long hole 45 so that the downstream long hole 45 can be moved smoothly. Further, even if the bracket 12 is swung clockwise 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.

  Further, as shown in FIG. 24, the downstream slot 45 may be tilted so that the upper end of the downstream slot 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 downstream elongated 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 downstream slot, when the adsorption separation unit 110 swings from the feeding position to the adsorption position, the downstream tension roller 5 However, 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 downstream elongated hole 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. 25, when the suction separation unit 110 is stopped at the suction position, the downstream long hole 45 may extend in a direction perpendicular to the sheet bundle. With this configuration, the downstream tension roller 5 is urged straight in the vertical direction with respect to the upper surface of the sheet bundle 1 by the spring 46. Therefore, the suction belt 2 can be favorably biased toward the sheet bundle by the spring 46, and the uppermost sheet 1a can be favorably attracted to the suction belt 2.

  Next, features of the sheet conveying apparatus 200 provided in the copying machine 100 according to the present embodiment will be described.

FIG. 26 is a schematic diagram of the sheet conveying apparatus 200 showing the characteristic part of the present embodiment, and FIG. 27 is a cross-sectional view taken along line AA of FIG. FIG. 28 is a view of FIG. 27 viewed from the B direction.
As shown in FIG. 26, the sheet conveying apparatus 200 is provided with a pressing member 80 that is disposed inside the suction belt 2 and presses the suction belt 2 toward the sheet bundle 1. The pressing member 80 is fixed to a rotating shaft 81 that is rotatably supported by each bracket 12. Arc-shaped pressing portions 80 a, 80 b, and 80 c that press the suction belt 2 are provided at three locations in the rotation direction of the pressing member 80. The distances from the center of the rotation shaft 81 of the pressing portions 80a, 80b, and 80c are different from each other. When the distance from the rotation axis center of the first push portion 80a is A, the distance from the rotation axis center of the second push portion 80b is B, and the distance from the rotation axis center of the third push portion 80c is C, A < B <C. Further, the curvatures of the pressing portions 80a, 80b, and 80c are also different from each other. When the curvature of the first push portion 80a is A1, the curvature of the second push portion 80b is B1, and the curvature of the third push portion 80c is C1, the relationship is A1 <B1 <C1.

  As shown in FIG. 27, four pressing members 80 are provided at equal intervals in the sheet width direction. The rotation shaft 81 is rotatably supported by a bearing 81a movably held in a pressing member long hole 12b extending in a vertical direction with respect to the sheet surface of the sheet bundle formed on each bracket 12 (see FIG. 28). Further, a spring 82 is provided in the long hole 12b for the pressing member, and the bearing 81a is urged toward the sheet bundle side by the spring 82. Further, a pressing member driving mechanism 90 for rotating the pressing member 80 is provided on the bracket on the back side of the apparatus.

  FIG. 29 is a schematic diagram illustrating a configuration of the pressing member driving mechanism 90. 29A is a front view of the pressing member driving mechanism 90, FIG. 29B is a view as viewed from the opposite side to FIG. 29A, and FIG. 29C is a pressing member driving. It is a figure explaining fixation to the bracket 12 of the mechanism 90. FIG.

  The pressing member drive mechanism 90 includes a drive holding member 94 supported by the bracket 12 so as to be movable in the direction of arrow Z in the figure. A drive motor 91 is attached to the drive holding member 94. A screw gear 92 is attached to the drive shaft of the drive motor 91. One end of the rotation shaft 81 passes through the drive holding member 94, and a helical gear 93 that meshes with the screw gear 92 is fixed to one end thereof.

  As shown in FIG. 29 (c), the drive holding member 94 is provided with three leg portions 94 b and passes through drive attachment holes 95 provided in the bracket 12 at three locations. As shown in FIG. 29 (b), the drive mounting holes 95 are provided on the upper side, the lower side, and the right side of the pressing member long hole 12b in the drawing, respectively, with respect to the sheet surface of the sheet bundle. It has a long hole shape extending in the vertical direction.

  As shown in FIG. 29 (c), a retaining member 94a such as an e-ring is fixed to the tip of each leg portion 94b, whereby the pressing member driving mechanism 90 is attached to the bracket 12 in the drawing. It is supported so as to be movable in the arrow Z direction. As described above, the pressing member driving mechanism 90 is supported by the bracket 12 so as to be movable in the arrow Z direction in the figure, so that the pressing member driving mechanism 90 can be moved in conjunction with the movement of the rotating shaft 81.

  A control unit 96 is connected to the drive motor 91. Sheet information input by the user from the operation panel 97 is input to the control unit 96. Based on this sheet information, as will be described later, the control unit 96 controls the drive motor 91 to bring the appropriate pressing unit into contact with the suction belt 2.

  In the sheet conveying apparatus 200 of the present embodiment, the suction belt 2 is pushed toward the sheet bundle 1 by the pressing member 80, and the surface of the suction belt 2 on which the sheet is sucked is bent to be sucked onto the suction belt 2. Bend the sheet. Thereby, the second sheet of the sheet bundle is separated from the suction belt 2. The separation operation will be described below with reference to FIG.

  As shown in FIG. 30A, the pressing member 80 is pushed up by the sheet bundle 1 when the charged suction belt 2 is in contact with the uppermost sheet 1 a of the sheet bundle. For this reason, the bearing 81 a that has been in contact with the lower end of the pressing member long hole 12 b is positioned above the urging force of the spring 82.

  After the uppermost sheet 1a is adsorbed to the adsorption belt 2 after waiting for a predetermined time, when the adsorption separation unit 110 is swung counterclockwise in the figure with the support shaft 14 as a fulcrum, the downstream tension roller 5 is , Together with the bracket 12, moves away from the sheet bundle 1. On the other hand, the pressing member 80 does not move from the upper surface of the sheet bundle 1 due to the urging force of the spring 82, and moves in the sheet bundle direction relative to the bracket 12. Similarly, the upstream tension roller 6 does not move from the upper surface of the sheet bundle 1 as described above. For this reason, as shown in FIG.30 (b), the surface which the uppermost sheet | seat 1a of the adsorption | suction belt 2 adsorb | sucks is bent by using the location where the pressing member 80 is contact | abutting as a fulcrum. When the suction belt 2 is bent with the place where the pressing member 80 is in contact as a fulcrum, the sheet sucked on the suction belt 2 is also bent following the suction belt 2. Further, when the suction separation unit 110 is swung, the inclination angle with respect to the sheet bundle on the downstream side in the sheet conveying direction becomes larger than the contact portion of the pressing member 80 of the suction belt 2. Thereby, the sheet adsorbed on the adsorption belt 2 is further bent with the pressing member 80 as a fulcrum. Then, as shown in FIG. 30 (c), when the adsorption separation unit 110 further rotates counterclockwise in the drawing with the support shaft 14 as a fulcrum, the bearing 81a hits the lower end of the pressing member long hole 12b. As a result, the pressing member 80 moves together with the bracket 12 and is separated from the upper surface of the sheet bundle 1. Immediately before the pressing member 80 is separated from the sheet bundle 1, the sheet adsorbed on the adsorption belt is bent most. Therefore, until the pressing member 80 is separated from the sheet bundle 1, the second sheet that is in close contact with the uppermost sheet by the adhesion force is separated from the uppermost sheet by its own stiffness.

  Next, the shaft 6 a of the upstream tension roller 6 hits the lower end of the long hole 12 a, and the upstream tension roller 6 is separated from the upper surface of the sheet bundle 1. Thereafter, as described above, the suction belt 2 is rotated, and the uppermost sheet adsorbed on the suction belt 2 is conveyed. The timing at which the shaft 6a of the upstream tension roller 6 hits the lower end of the long hole 12a may be the same as the timing at which the bearing 81a hits the lower end of the pressing member long hole 12b.

  The amount of bending for separating the second sheet from the suction belt 2 without the uppermost sheet 1a being peeled off from the suction belt 2 varies depending on the rigidity of the sheet. For example, a highly rigid sheet such as cardboard is strong, so that the second sheet can be separated by simply bending it lightly. On the contrary, when the sheet adsorbed on the adsorption belt 2 is bent tightly, the uppermost sheet 1 a is peeled off from the adsorption belt 2. On the other hand, in the case of a sheet having low rigidity, even if the sheet adsorbed on the adsorption belt 2 is bent lightly, the second sheet is not separated. For this reason, when the sheet has low rigidity, the second sheet cannot be separated unless the sheet adsorbed on the adsorption belt is bent tightly.

  For this reason, in this embodiment, the pressing amount to the suction belt 2 by the pressing member 80 is configured to be switchable, and the bending amount of the suction belt 2 can be changed by switching the pressing amount. Yes.

  As shown in FIG. 31 (1), when the rigidity of the sheet stored in the paper feed cassette 11 is high, the first pressing portion 80 a of the pressing member 80 is brought into contact with the suction belt 2. As described above, the distance from the center of the rotation axis of the first pressing portion 80a is shorter than other pressing portions. Therefore, the pressing amount by the pressing member 80 is less than that of other pressing portions. Accordingly, the pressing member 80 is separated from the sheet bundle 1 at a stage where the inclination angle with respect to the sheet bundle on the downstream side in the sheet conveying direction from the contact position of the pressing member 80 of the suction belt 2 is small. As a result, the amount of bending of the suction belt 2 with the location where the pressing member 80 is in contact as a fulcrum is smaller than when the other pressing portions are in contact. That is, the sheet adsorbed on the adsorption belt 2 is only bent lightly. Accordingly, in the highly rigid sheet, the second sheet can be separated from the suction belt 2 without the uppermost sheet 1 a being peeled off from the suction belt 2.

  When the sheet stored in the paper feed cassette 11 is changed from a high-rigidity sheet such as cardboard to a low-rigidity sheet such as plain paper, the pressing member 80 is moved as shown in FIG. The second pressing portion 80b is brought into contact with the suction belt 2 by rotating. Specifically, the user operates the operation panel 97 to select the type of sheet stored in the paper feed cassette 11. For example, by operating the operation panel, it is possible to select whether the sheet stored in the paper feed cassette 11 is thick paper, plain paper, or thin paper. When the card is changed from thick paper to plain paper by the user's operation, the control unit 96 controls the driving motor 91 of the pressing member driving mechanism 90 to rotate the pressing member 80. And the control part 96 stops the drive motor 91 at the timing which the 2nd press part 80b contact | abuts to the adsorption | suction belt 2. FIG.

  As described above, the distance from the center of the rotation axis of the second pressing portion 80b is longer than that of the first pressing portion 80a. Therefore, the pressing amount by the pressing member 80 is larger than that of the first pressing portion 80a. Therefore, as shown in FIG. 31 (3), the inclination angle of the suction belt immediately before the pressing member 80 is separated from the sheet bundle 1 is larger than that of the high-rigidity sheet shown in FIG. 31 (1). growing. As a result, the amount of bending of the suction belt 2 with the location where the pressing member 80 is in contact as a fulcrum is greater than when the first pressing portion 80a is in contact. Therefore, the sheet adsorbed on the adsorbing belt 2 is tightly bent as compared with the case where the first pressing portion 80a is in contact. Therefore, the second sheet can be satisfactorily separated from the suction belt 2 in the low-rigidity sheet.

  Although not shown, when the sheet stored in the sheet feeding cassette 11 is an ultra-low rigidity sheet such as thin paper, the third pressing portion 80 c of the pressing member 80 is brought into contact with the suction belt 2. As described above, the distance from the center of the rotation axis of the third pushing portion 80c is longer than the other pushing portions. Therefore, the amount of pressing by the pressing member 80 is larger than that of other pressing portions. Therefore, when the pressing member 80 is separated from the sheet bundle, the inclination angle of the suction belt with respect to the sheet bundle becomes larger than when the other pressing portions are brought into contact with each other. As a result, the amount of bending of the suction belt 2 with the location where the pressing member 80 is in contact as a fulcrum increases compared to when the other pressing portion is in contact. Therefore, the sheet adsorbed on the adsorption belt 2 is bent most tightly. Therefore, the second sheet can be satisfactorily separated from the suction belt 2 even in an ultra-low-rigidity sheet such as thin paper that has very weak stiffness.

  Thus, in the present embodiment, the second sheet can be satisfactorily separated from the suction belt 2 without the uppermost sheet 1a being peeled from the suction belt 2 from the ultra-low rigidity sheet to the high rigidity sheet. .

In the present embodiment, as described above, when the curvature of the first pushing portion 80a is A1, the curvature of the second pushing portion 80b is B1, and the curvature of the third pushing portion 80c is C1, A1 <B1 < The relationship is C1. When the suction belt 2 is bent with the pressing member 80 as a fulcrum, the suction belt bends in accordance with the shape of the contact surface of the pressing portion that is in contact with the suction belt. That is, it bends with the curvature of the pushing portion. Thereby, the sheet bent along the suction belt 2 is also bent at the curvature of the pressing portion.
The present inventors have found that the sheet separability is greatly influenced by the curvature of the sheet bending portion. As described above, the curvature of the bent portion of the sheet can be controlled to some extent by controlling the amount of bending of the sheet by varying the inclination angle of the suction belt 2 depending on the rigidity of the sheet, but it cannot be accurately controlled. For example, in a highly rigid sheet, even if the sheet is bent with an optimum bending amount for separating the second sheet, if the curvature of the bent portion is large, the sheet is tightly bent at the bent portion, and the uppermost sheet 1a is There is a risk of peeling off the suction belt 2. On the other hand, in a sheet with low rigidity, even if the amount of bending of the sheet is increased, if the curvature is small, the sheet does not bend at the bent portion. Therefore, even if the bending amount of the sheet is increased, the second sheet may not be separated from the uppermost sheet.

  However, in the present embodiment, the curvature of the first pressing portion 80a corresponding to a highly rigid sheet such as cardboard is made smaller than the curvature of the other pressing portions. Thereby, a highly rigid sheet | seat can be reliably lightly bent in a bending location, and it can suppress favorably that the uppermost sheet | seat peels from the adsorption | suction belt 2. FIG. In addition, the curvature of the third pressing portion 80c corresponding to an ultra-low-rigidity sheet such as thin paper is made larger than the curvature of the other pressing portions. As a result, the ultra-low rigidity sheet can be securely bent at the bent portion, and the second sheet can be reliably separated from the uppermost sheet.

In the present embodiment, the vicinity of the front end of the sheet can be bent by providing the pressing member 80. The closer to the tip, the smaller the area for peeling the second sheet from the uppermost sheet, so that the force required for peeling (the stiffness of the second sheet) can be reduced. Therefore, the second sheet can be separated from the uppermost sheet without bending the sheet so much. As a result, the angle of inclination of the suction belt 2 with respect to the sheet bundle can be reduced, and the swing amount of the suction separation unit 110 can be suppressed. Further, by providing the pressing member 80, the suction belt 2 can be bent with the vicinity of the downstream tension roller 5 as a fulcrum. As a result, it becomes easier to incline the downstream side of the sheet conveyance direction than the contact portion of the pressing member 80 of the suction belt. As a result, the distance from the sheet bundle of the downstream tension roller 5 until the suction belt 2 has a predetermined inclination angle is suppressed as compared with the case where the sheet is bent with the upstream tension roller 6 as a fulcrum. Can do. As a result, the swing amount of the adsorption separation unit 110 can be further suppressed.
Thus, by providing the pressing member 80, the amount of swinging of the adsorption separation unit 110 can be suppressed, the movement time between the adsorption position and the transport position can be shortened, and productivity (per unit time) can be reduced. The number of transported sheets) can be improved.

  In the present embodiment, the pressing member 80 is rotatably provided, and the pressing member 80 is rotated to change the pressing amount with respect to the suction belt 2. Thereby, the pressing amount to the suction belt can be changed with one pressing member 80, and the bending amount of the suction belt 2 can be changed. Therefore, compared with the case where a plurality of pressing members having different pressing amounts with respect to the suction belt 2 are provided and any one of the plurality of pressing members is brought into contact with the suction belt to change the pressing amount, the number of parts is smaller. Can be reduced. As a result, the cost of the apparatus can be reduced.

  Further, when a plurality of pressing members having different pressing amounts with respect to the suction belt 2 are provided, the positions where the suction belt 2 is bent are different from each other. In order to obtain good separability, it is preferable to bend the vicinity of the leading end side of the sheet as much as possible. However, when a plurality of pressing members are provided, the positions at which the suction belt 2 is bent are different from each other. Therefore, there are some cases where the sheet is bent and separated at a position away from the leading end of the sheet. As described above, when the sheet is bent and separated at a position away from the leading end of the sheet, it is necessary to increase the amount of bending of the sheet. As a result, productivity may be reduced.

  On the other hand, in this embodiment, even if the pressing amount is changed, the position where the suction belt 2 is bent by the pressing member 80 is not changed. Therefore, in any rigid sheet, the vicinity of the front end of the sheet can be bent and separated. Thereby, the bending amount of a sheet | seat can be suppressed and the rocking | fluctuation amount of the adsorption separation unit 110 can be suppressed. Therefore, a decrease in productivity can be suppressed.

  In this embodiment, the pressing member driving mechanism 90 is provided and the pressing member 80 is rotated by the driving force of the drive motor 91. However, the user may manually rotate the pressing member 80.

  In the above description, the upstream tension roller 6 is kept in contact with the upper surface of the sheet bundle until the shaft 6a of the upstream tension roller 6 comes into contact with the lower end of the long hole 12a. However, when the rigidity of the sheet is high, the upstream tension roller 6 is lifted from the upper surface of the sheet bundle 1 before the shaft 6a of the upstream tension roller 6 hits the lower end of the long hole 12a due to the repulsive force of the sheet. There is. Further, when the suction separation unit 110 is swung from the suction position to the transport position at a high speed, the upstream tension roller 6 may be separated from the lower end of the long hole 12a due to inertial force. As a result, the suction belt 12 vibrates at the transport position, and the uppermost sheet 1a sucked on the suction belt 12 may be peeled off, resulting in a transport failure.

  Therefore, as shown in FIG. 32, the upstream tension roller 6 may be urged toward the lower end side of the elongated hole 12a by the tension spring 161. In this configuration, the boss 162 is provided below the long hole 12 a of the bracket 12. Then, one end of the tension spring 161 is hooked on the boss portion 162, and the other end of the tension spring 161 is hooked on the shaft 6 a of the upstream tension roller 6. Thereby, the upstream tension roller 6 is urged toward the lower end side of the elongated hole 12 a, and the shaft 6 a abuts against the urging force of the tension spring 161. In such a configuration, when the suction belt 2 is moved from the conveyance position to the suction position, when the upstream tension roller 6 comes into contact with the upper surface of the sheet bundle, the tension spring 161 is extended, and the upstream tension roller 6. Is separated from the lower end of the long hole 12a. When the suction separation unit 110 is swung from the suction position to the transport position, the biasing force of the tension spring 161 moves the shaft 6a of the upstream tension roller 6 toward the lower end of the elongated hole 12a. As a result, the upstream tension roller 6 continues to contact the upper surface of the sheet bundle by the biasing force of the tension spring 161. Thereby, even if the rigidity of the sheet to be adsorbed by the adsorption belt 2 is high, before the shaft 6a of the upstream tension roller 6 hits the lower end of the long hole 12a due to the repulsive force of the sheet, the upstream tension roller 6 It is possible to prevent the sheet bundle 1 from being lifted from the upper surface. Further, even after the shaft 6 a of the upstream tension roller 6 hits the lower end of the elongated hole 12 a and is lifted by the bracket 12, it is abutted against the lower end of the elongated hole 12 a by the urging force of the tension spring 161. Therefore, when the adsorption separation unit 110 is swung from the adsorption position to the conveyance position at a high speed and stopped at the conveyance position, the upstream tension roller 6 moves in a direction away from the lower end of the long hole 12a by inertia force. This can be prevented by the biasing force of the tension spring 161. Thereby, the vibration of the suction belt 2 when the suction separation unit 110 is swung from the suction position to the transport position at a high speed can be suppressed, and the uppermost sheet 1a is prevented from peeling off from the suction belt 2 during the transport. can do.

  In the above description, the uppermost sheet of the sheet bundle is attracted to the suction belt 2 by electrostatic attraction force. However, the uppermost sheet of the sheet bundle is attracted to the adsorption belt 2 by air suction force. The present invention can also be applied to a sheet conveying apparatus.

FIG. 33 is a schematic diagram showing an air suction type sheet conveying apparatus 400.
As shown in FIG. 33, the sheet conveying apparatus 400 is provided with a sheet suction unit 401 that sucks air from a plurality of suction holes provided in the suction belt 2 in a space that is an inner periphery of the sheet conveyance device 400.

  The air suction unit 401 is connected to a control unit (not shown), and by sucking air from the suction hole of the suction belt 2 by a signal from the control unit, among the sheet bundle 1 stacked on the bottom plate 7, The uppermost sheet 1 a is adsorbed to the adsorption belt 2. In a state where the uppermost sheet 1a is adsorbed to the adsorbing belt 2, a control unit (not shown) drives the adsorbing belt 2 and moves the adsorbing belt 2 to move the surface, thereby conveying the adsorbed uppermost sheet 1a.

  In the air suction type sheet conveying apparatus 400, when a sheet having high surface smoothness such as OHP paper, art paper, coated paper, or the like is used, the adhesion between the sheets becomes high in a stacked state. For this reason, when the uppermost sheet is sucked to the suction belt 2 by air suction, the second sheet may not be separated due to the adhesion with the uppermost sheet.

  Therefore, also in the air suction type sheet conveying apparatus 400, the pressing member 80 is provided to adsorb the uppermost sheet 1a, and then the adsorbing belt 2 is pressed against the sheet bundle 1 by the pressing member 80 to bend the adsorbing belt 2. . Thereby, the leading end portion of the uppermost sheet adsorbed on the adsorption belt 2 is turned, and the second sheet that is in close contact with the uppermost sheet can be satisfactorily separated.

What has been described above is an example, and the present invention has a specific effect for each of the following aspects.
(Aspect 1)
A rotatable endless suction belt 2 disposed opposite to the upper surface of the stacked sheet bundle 1, a first tension roller such as a downstream tension roller 5 that stretches the suction belt 2, and the first tension roller. An adsorption / separation unit 110 having a second stretching roller such as an upstream stretching roller 2 positioned on the upstream side in the sheet conveyance direction of the stretching roller, and a charging member for attracting the uppermost sheet 1a of the sheet bundle 1 to the suction belt 2 3 and the sheet bundle 1 and the suction belt 2 are in contact with each other, and the suction position relationship in which the uppermost sheet 1a of the sheet bundle 1 is attracted to the suction belt 2, and the sheet bundle 1 and the suction belt 2 are in contact with each other. A swinging mechanism 1 that moves at least one of the adsorption separation unit 110 and the sheet bundle 1 so as to be able to selectively take a conveyance positional relationship that conveys the uppermost sheet 1a adsorbed to the adsorption belt 2 in a separated relationship. In the sheet conveying apparatus 200 having a moving means such as 0, the second stretching roller in the adsorption region where the uppermost sheet 1a of the sheet bundle of the adsorption belt 2 adsorbs when shifting from the adsorption position relationship to the conveyance position relationship. The suction belt 2 is pressed against the sheet bundle at a position downstream of the sheet conveying direction with respect to the sheet bundle, and the suction belt 2 on the downstream side of the sheet conveying direction with respect to the pressing position is inclined with respect to the sheet bundle 1 in accordance with the transition. However, when the predetermined angle is reached, a pressing member 80 that is separated from the sheet bundle 1 together with the suction belt 2 is provided, and the inclination angle when the pressing member 80 is separated from the sheet bundle 1 can be changed.
As described in the embodiment, the present applicant has intensively studied to improve productivity and found the following. That is, it has been found that the closer the position where the sheet is bent is to the front end of the sheet, the smaller the inclination angle of the suction belt with respect to the sheet bundle for separating the second sheet from the uppermost sheet. In order to bring the sheet bending position closer to the leading end of the sheet, for example, the distance between the first stretching roller and the second stretching roller is made shorter than before, the suction area of the suction belt is made narrower than before, and the second tension roller is made smaller. It is also conceivable to bend the vicinity of the leading edge of the sheet with a frame roller. However, in this case, only the vicinity of the front end of the sheet is adsorbed to the adsorption belt. Therefore, when the uppermost sheet adsorbed on the suction belt by rotating the suction belt 2 is transported, it may be peeled off from the suction belt due to vibration or the like, which may cause a transport failure.
Therefore, in the first aspect, the suction belt is pressed against the sheet bundle by the pressing member disposed on the downstream side in the sheet conveying direction with respect to the second stretching roller such as the upstream stretching roller 6 and the sheet is pressed from the pressing position of the pressing member. The downstream side in the conveying direction was inclined with respect to the sheet bundle. Thereby, the sheet adsorbed on the adsorption belt is bent with the pressing position of the pressing member as a fulcrum. Accordingly, the sheet bending position is made closer to the leading edge of the sheet as compared with the sheet conveying apparatus while securing an adsorption area equivalent to that of the sheet conveying apparatus described in Patent Document 1 that bends and separates the sheet with the second stretching roller. be able to. As a result, as compared with the sheet conveying apparatus described in Patent Document 1, while suppressing the peeling of the uppermost sheet from the suction belt, the second belt is separated from the uppermost sheet with respect to the sheet bundle. The inclination angle can be reduced. Thereby, compared with the sheet conveying apparatus described in Patent Document 1, it is possible to suppress the amount of movement of the suction belt relative to the sheet bundle when shifting from the suction position relationship to the conveyance position relationship, thereby increasing productivity. Can do.

  In the aspect 1, the inclination angle when the pressing member 80 is separated from the sheet bundle can be changed, and the inclination angle can be changed according to the rigidity of the sheet as in Patent Document 1. Thereby, like patent document 1, favorable separability can be acquired irrespective of sheet rigidity.

(Aspect 2)
In (Aspect 1), the pressing member 80 includes a plurality of pressing portions 80a, 80b, and 80c that have different pressing amounts for pressing the suction region of the suction belt 2 toward the sheet bundle side and bending the suction belt 2, and the suction belt 2 2 is provided with a switching means (in this embodiment, configured by a pressing member driving mechanism 90, a control unit 96, an operation panel 97, and the like) for switching a pressing portion that abuts against 2.
By providing such a configuration, the inclination angle when the pressing member 80 is separated from the sheet bundle 1 can be changed as described in the embodiment.

(Aspect 3)
In (Aspect 2), the pressing member 80 is rotatably supported, and the switching unit includes a driving unit such as a pressing member driving mechanism 90 that rotationally drives the pressing member 80.
By providing such a configuration, it is possible to change the push amount without moving the contact portion with the suction belt 2. As a result, the vicinity of the front end of the sheet can be bent at any pressing amount. Thereby, it is possible to obtain a good separation property while suppressing the inclination angle. Therefore, the amount of movement of the suction belt relative to the sheet bundle when shifting from the suction position relationship to the conveyance position relationship can be suppressed. Productivity can be increased.

(Aspect 4)
In (Aspect 3), the plurality of pressing portions 80a, 80b, and 80c are different from each other in the distance of the pressing member 80 from the rotation shaft 81.
By providing such a configuration, as described in the embodiment, the pressing amounts of the pressing portions 80a, 80b, and 80c can be made different from each other.

(Aspect 5)
In any one of (Aspect 2) to (Aspect 4), the switching means such as the pressing member driving mechanism 90 switches the sheets of the stacked sheet bundle 1 to a sheet having rigidity lower than a predetermined threshold value. The pressing member 80 is rotationally driven so that the pressing portion 80c having the largest pressing amount abuts against the suction belt 2 among the plurality of pressing portions, and the sheets of the stacked sheet bundle are sheets whose rigidity is higher than a predetermined threshold value. When switched to, the pressing member 80 is driven to rotate so that the pressing portion 80a having the smallest pressing amount among the plurality of pressing portions comes into contact with the suction belt 2.
By providing such a configuration, as described in the embodiment, an optimum inclination angle corresponding to the seat rigidity can be obtained.

(Aspect 6)
In any one of (Aspect 2) to (Aspect 6), the contact surfaces of the pressing portions 80a, 80b, and 80c with the suction belt 2 are curved surfaces, and the curvatures of the pressing portions 80a, 80b, and 80c are different from each other. Let
By providing such a configuration, as described in the embodiment, the sheet can be bent with a desired curvature, and good separability can be obtained.

(Aspect 7)
In any one of (Aspect 1) to (Aspect 6), the suction unit includes a charging unit such as a charging member 3 that charges the surface of the suction belt so that the sheet is electrostatically suctioned to the suction belt 2.
By providing such a configuration, a blower and an air duct are not required, and the apparatus can be reduced in size as compared with a case where a sheet is adsorbed to the adsorption belt 2 by air suction. Further, since no air suction sound or the like is generated, noise can be suppressed as compared with the case where the sheet is sucked onto the suction belt 2 by air suction.

(Aspect 8)
In any one of (Aspect 1) to (Aspect 6), the suction unit includes an air suction unit such as a sheet suction unit 401 that sucks the sheet onto the suction belt by the suction force of air.
By providing such a configuration, it is possible to reduce power consumption compared to a sheet that is electrostatically adsorbed to the adsorption belt 2. Further, the sheet can be adsorbed to the adsorption belt using an inexpensive fan or duct, and the apparatus can be made cheaper than the apparatus that electrostatically adsorbs the adsorption belt 2 that requires an expensive power supply device. Can do.

(Aspect 9)
In any one of (Aspect 1) to (Aspect 8), the moving means such as the swing mechanism 120 is connected to the first drive transmission unit attached to the downstream end of the adsorption separation unit 110 in the sheet conveyance direction, and the apparatus main body. A second drive transmission unit that meshes with the attached first drive transmission unit is provided, and the adsorption separation unit 110 is swung by meshing between the first drive transmission unit and the second drive transmission unit.
By providing such a configuration, as described above, the adsorption separation unit 110 can be supported at both ends when the adsorption separation unit 110 is swung, and vibration of the adsorption separation unit 110 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 110, the load on the swing mechanism 120 can be reduced. Thereby, the enlargement of the swing motor 30 can be avoided, and wear of the meshing portion between the first drive transmission portion and the second drive transmission portion can be suppressed.

(Aspect 10)
In any one of (Aspect 1) to (Aspect 9), the moving means moves up and down the bottom plate 7 on which the sheet bundle 1 is stacked (in this embodiment, the support member 8 and the support member are driven to rotate). It comprises a drive motor (not shown).
Even with this configuration, the suction belt 2 can take the suction position and the transport position.

(Aspect 11)
In any one of (Aspect 1) to (Aspect 10), the adsorption separation unit 110 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.
By providing such a configuration, as described in the embodiment, it is possible to perform separation utilizing the restoring force of the sheet, and it is possible to obtain good separation performance. Further, the suction belt 2 can be separated from the upper surface of the sheet bundle 1 only by swinging the suction separation unit 110.

(Aspect 12)
An image forming unit such as an image forming unit 50 that forms an image on a sheet, and a sheet conveying unit such as a sheet conveying device 200 that separates the uppermost sheet from the stacked sheet bundle and conveys the uppermost sheet to the image forming unit. In the image forming apparatus such as the copying machine 100 including the above, the sheet conveying unit includes any one of (Aspect 1) to (Aspect 11).
According to this, as described in the above embodiment, when a highly rigid sheet is used, the sheet adsorbed on the adsorption belt can be prevented from being peeled off, and image formation can be performed by performing good sheet conveyance. It can be performed. In addition, even when a low-rigidity sheet is used, it is possible to suppress the occurrence of double feeding, and it is possible to suppress the occurrence of a jam.

DESCRIPTION OF SYMBOLS 1 Sheet bundle 1a Top sheet 1b Second sheet 2 Adsorption belt 3 Charging member 4 Charging power source 5 Downstream tension roller 6 Upstream tension roller 7 Bottom plate 8 Support member 9 Conveying roller pair 10 Guide member 11 Paper feed cassette 12 Bracket 12a Upstream slot 12b Push member slot 13 Rack gear section 14 Support shaft 15 Pinion gear 16 Rotating shaft 20 Housing 20a Housing body section 20b Shaft hole section 20c Fixing screw 21 Spring 22 Bearing 23 Rib 24a Motor shaft 24 Drive motor 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 41 lower end 41a lower end surface 45 downstream slot 46 Spring 47 driven pulley 4 First timing belt 49 Second 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 59a Document tray 59 Automatic document feeder 61 Photoconductor 62 charging device 63 laser light 64 developing device 65 photoconductor cleaning device 70 reinforcing member 80 pressing member 80a first pressing portion 80b second pressing portion 80c third pressing portion 81 rotating shaft 81a bearing 82 spring 90 pressing member driving mechanism 91 driving motor 92 screw gear 93 helical gear 94 drive holding member 94a retaining member 94b leg 95 drive mounting hole 100 copier 103 electrode member 110 adsorption separation unit 112 bracket 113 rotation gear 114 rotation shaft 115 rotation gear 116 motor shaft 117 rotation Motor 1 20 swing mechanism 130 drive mechanism 140 sheet detection means 142 shaft 143 transmissive optical sensor 143a light receiving unit 143b light emitting unit 144 filler 200 sheet conveying device 310 driving pulley 400 sheet conveying device 401 air suction unit 401 sheet suction unit

JP 2012-56711 A

Claims (12)

A rotatable 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 position upstream of the first tension roller in the sheet conveyance direction An adsorption separation unit having a second stretching roller
Adsorbing means for adsorbing the uppermost sheet of the sheet bundle to the adsorbing belt;
The sheet bundle and the suction belt are in contact with each other, the suction position relation for sucking the uppermost sheet of the sheet bundle to the suction belt, and the sheet bundle and the suction belt are in a separated relation, and the suction belt In a sheet conveying apparatus comprising a moving unit that moves at least one of the adsorption separation unit and the sheet bundle so that a conveyance positional relationship for conveying the uppermost sheet adsorbed on the sheet can be selectively taken,
When shifting from the suction position relationship to the transport position relationship, the suction belt is moved at a position downstream of the second stretching roller in the suction region where the uppermost sheet of the sheet bundle of the suction belt sucks. The sheet bundle is pressed together with the suction belt when the inclination angle at which the suction belt on the downstream side in the sheet conveying direction with respect to the pressing position is inclined with respect to the sheet bundle becomes a predetermined angle. A pressing member spaced apart from the
A sheet conveying apparatus configured to be able to change the inclination angle when the pressing member is separated from the sheet bundle. In the sheet conveying apparatus according to claim 1,
The pressing member has a plurality of pressing portions with different pressing amounts for pressing the suction region of the suction belt toward the sheet bundle side and bending the suction belt,
A sheet conveying apparatus comprising switching means for switching a pressing portion in contact with the suction belt. In the sheet conveying apparatus according to claim 2,
The pressing member is rotatably supported,
The sheet conveying apparatus, wherein the switching unit includes a driving unit that rotationally drives the pressing member. In the sheet conveying apparatus according to claim 3,
The plurality of pressing portions are different from each other in distance from the rotation axis of the pressing member. The sheet conveying apparatus according to any one of claims 2 to 4,
The switching means is configured such that when the stacked sheet bundle sheet is switched to a sheet having a rigidity lower than a predetermined threshold, a pressing portion with the largest pressing amount among the plurality of pressing portions is applied to the suction belt. When the pressing member is rotated so as to abut, and the sheets of the stacked sheet bundle are switched to a sheet having rigidity higher than a predetermined threshold, the pressing amount of the plurality of pressing portions is the smallest The sheet conveying apparatus, wherein the pressing member is rotationally driven so that the pressing portion comes into contact with the suction belt. In the sheet conveying apparatus according to any one of claims 2 to 5,
The contact surface of each pressing portion with the suction belt is a curved surface,
A sheet conveying apparatus characterized in that the curvature of each pressing portion is different from each other. In the sheet conveying apparatus according to any one of claims 1 to 6,
The sheet conveying apparatus, wherein the suction unit includes a charging unit that charges the surface of the suction belt so that the sheet is electrostatically suctioned to the suction belt. In the sheet conveying apparatus according to any one of claims 1 to 7,
The sheet conveying apparatus, wherein the suction unit includes an air suction unit that sucks the sheet onto the suction belt by an air suction force. In the sheet conveying apparatus according to any one of claims 1 to 8,
The moving means includes a first drive transmission unit attached to the downstream end of the adsorption separation unit in the sheet conveyance direction, and a second drive transmission unit meshing with the first drive transmission unit attached to the apparatus main body. A sheet conveying apparatus that moves the adsorption / separation unit by meshing between the first drive transmission unit and the second drive transmission unit. The sheet conveying apparatus according to any one of claims 1 to 9,
The sheet conveying apparatus according to claim 1, wherein the moving unit includes an elevating unit that elevates and lowers a bottom plate on which the sheet bundle is stacked. The sheet conveying apparatus according to any one of claims 1 to 10,
When the first and second stretching rollers are in contact with the uppermost sheet of the sheet bundle via the suction belt, the suction and separation unit is configured to move the first and second stretching rollers. A sheet conveying apparatus, wherein each stretching roller is supported so that the supporting of the stretching roller is released. Image forming means for forming an image on a sheet;
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;
An image forming apparatus comprising the sheet conveying apparatus according to claim 1 as the sheet conveying unit.

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