JP2011162344A - Sheet carrying device and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet carrying device and an image forming device capable of reducing damage of a sheet and a sheet suction carrier. <P>SOLUTION: This sheet carrying device includes an air suction part 13 having a suction duct 13A having one end part connected to the inside of the sheet suction carrier 12 and arranging a suction fan 13C for generating suction force of the sheet suction carrier 12 in the other end part and a suction duct opening-closing part 13B arranged in the suction duct 13A and opening the suction duct 13A to outside air when opening, and a controller 19 for sucking and carrying the uppermost sheet 2A by the sheet suction carrier 12 and reducing the suction force of the uppermost sheet 2A by the sheet suction carrier 12 by opening the suction duct opening-closing part 13B when the tip of the uppermost sheet 2A reaches a downstream side sheet carrier 21. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a sheet conveying apparatus and an image forming apparatus that separate and convey a top sheet from a sheet bundle by air suction.

  Conventionally, as a sheet conveying device for feeding a recording medium such as paper (hereinafter referred to as “sheet”) mounted on an image forming apparatus such as a digital copying machine, a printer apparatus, a facsimile apparatus, an offset printing machine, for example, An air suction type sheet conveying apparatus is known.

  An example of an air suction type sheet conveying apparatus is shown in FIGS.

  As shown in FIG. 10, in the sheet conveying apparatus 101, a sheet adsorbing / conveying unit 112 including a sheet adsorbing / conveying belt 112C is provided above the sheet storage unit 111, and is stacked on a stacking tray 111A that is a horizontal plane. A plurality of sheets (hereinafter, also referred to as “sheet bundles”) 102 A, which is the uppermost sheet in the vertical direction (hereinafter, referred to as “uppermost sheet”) 102 </ b> A, is taken sheet by sheet by the air suction unit 113. It is configured to be attracted to 112C and conveyed to a predetermined position.

  Further, a blower unit 114 is provided on the downstream side (right side in the drawing) in the sheet conveying direction, and air is blown to one end of the sheet bundle 102 to separate the sheets near the uppermost sheet 102A one by one. . On the other hand, a position detection sensor 116 is provided at an upstream end that is not affected by the air blown from the blower 114. The position detection sensor 116 includes a position detection unit (for example, a digital sensor) 116A and an upper surface position detection lever 116B.

  The stacking tray 111A is connected to the sheet lifting / lowering driving means 118 and can move up and down. The sheet bundle 102 ascends together with the stacking tray 111A, the uppermost sheet 102A comes into contact with the upper surface position detection lever 116B, and the position of the uppermost sheet 102A is detected by receiving the force by which the upper surface position detection lever 116B is pushed up. It is configured.

  A large number of suction holes (not shown) are formed on the entire surface of the sheet suction conveyance belt 112C. By the air suction from the air suction unit 113, the uppermost sheet 102A is sucked to the sheet suction conveyance belt 112C through the suction hole.

  With reference to FIG. 11, the sheet conveying operation of the sheet conveying apparatus 101 will be described.

  First, the stack raising / lowering drive unit 118 raises / lowers the stacking tray 111 </ b> A, and determines whether the position detection sensor 116 has detected the upstream end of the sheet bundle 102 in the conveyance direction of the uppermost sheet 102 </ b> A. When not detected, that is, when the uppermost sheet 102A is not in contact with the upper surface position detection lever 116B, the sheet raising / lowering driving means 118 further raises the stacking tray 111A, and the uppermost sheet 102A comes into contact with the upper surface position detection lever 116B. In this case, the sheet lifting / lowering driving means 118 stops the stacking tray 111A.

  Next, air is blown to the sheet bundle 102 by the blower unit 114, and adjacent sheets including the uppermost sheet 102A are separated one by one. The floated uppermost sheet 102A is adsorbed to the sheet adsorbing and conveying belt 112C by air suction from the air sucking unit 113, and the adsorbing uppermost sheet 102A is rotated by the driving device 117, thereby causing the adsorbed uppermost sheet 102A to be predetermined. To the position. By repeating this operation in accordance with the sheet feeding timing, the sheets are continuously conveyed one after another to a predetermined position.

  In such an air suction type sheet conveying apparatus 101, if the sheet suction conveying belt 112C continues to rotate after conveying the uppermost sheet 102A, the next sheet of the uppermost sheet 102A is conveyed, and the sheet at the target timing. Since the sheet cannot be transported, it is necessary to stop the rotation of the sheet suction transport belt 112C after transporting the sheet to the predetermined position by the sheet suction transport belt 112C.

  Therefore, in the sheet conveying apparatus 101, in order to enable the sheet conveyance even when the rotation of the sheet adsorption conveyance belt 112C is stopped, the sheet adsorption device belt 112C is on the near side of a predetermined position where the uppermost sheet 102A is conveyed. A downstream sheet conveying means comprising a pair of rollers (not shown) is provided separately (on the downstream side of the sheet conveying direction), and after stopping the sheet suction conveying belt 112C, the sheet is pulled by the separately provided downstream sheet conveying means. The sheet can be conveyed at this timing.

  However, in this case, since the downstream sheet conveying means pulls the sheet in a state where the sheet is adsorbed to the sheet adsorbing and conveying belt 112C by air suction from the air sucking unit 113, the sheet adsorbing and conveying belt 112C and the sheet There is a risk that the sheet adsorption / conveyance belt 112C and the sheet may be damaged by the friction force between them, that is, the sheet adsorption / conveyance belt 112C may be worn out or the sheet may be damaged.

  On the other hand, a technique is known in which a suction duct is closed by a predetermined amount immediately before the sheet is adsorbed to the sheet feeding belt to reduce the noise when the sheet is adsorbed to weaken the suction force ( For example, see Patent Document 1).

  However, even in the technique described in Patent Document 1, since the sheet is pulled while the sheet is adsorbed to the sheet feeding belt, the sheet feeding belt and the sheet rub against each other, and the sheet feeding belt is worn. The problem that the sheet is damaged or the sheet is damaged is not solved.

  SUMMARY An advantage of some aspects of the invention is that it provides a sheet conveying apparatus and an image forming apparatus that can reduce damage to a sheet and a sheet suction conveying unit.

  The sheet conveying apparatus according to the present invention includes a sheet storage unit that stacks and stores a sheet bundle on a stacking tray, a sheet elevating unit that elevates and lowers the sheet bundle stacked on the stacking tray, and the sheet elevating unit. An air blower that blows air from the downstream side in the sheet conveyance direction and lifts at least the uppermost sheet including the uppermost sheet of the sheet bundle to separate the sheets. A sheet suction conveyance unit that sucks and conveys the uppermost sheet floated by the blower, and a suction fan that has one end connected to the inside of the sheet adsorption conveyance unit and generates the suction force of the sheet adsorption conveyance unit at the other end And a suction duct opening / closing portion that is provided in the suction duct and that opens the suction duct to outside air when opened. Pulling means, downstream sheet conveying means provided on the downstream side in the sheet conveying direction of the sheet adsorption conveying means, further conveying the uppermost sheet conveyed by the sheet adsorption conveying means, and When the leading edge of the uppermost sheet reaches the downstream sheet conveying means by sucking and conveying the upper sheet, the suction duct opening / closing part is opened to reduce the adsorbing force of the uppermost sheet by the sheet adsorbing and conveying means. And a control means for making it possible.

  With this configuration, when the uppermost sheet is conveyed by the downstream sheet conveying means, the friction between the uppermost sheet and the sheet suction conveying means is reduced, and the uppermost sheet can be prevented from being damaged by the friction. Wear of the suction conveyance means can be reduced. Therefore, damage to the sheet and the sheet suction conveyance unit can be reduced.

  Further, in the sheet conveying apparatus according to the present invention, when the control unit sucks and conveys the uppermost sheet by the sheet adsorption conveying unit, and the leading end of the uppermost sheet reaches the downstream sheet conveying unit, The suction duct opening / closing part is opened, and the suction duct opening / closing part is closed when the rear end of the uppermost sheet is separated from the sheet suction conveyance means.

  With this configuration, it is possible to reduce damage to the sheet and the sheet suction conveyance unit.

  The sheet conveying apparatus according to the present invention is characterized in that the opening and closing of the suction duct opening / closing section is repeated for each sheet conveyance.

  With this configuration, it is possible to reduce damage to the sheet and the sheet suction conveyance unit.

  An image forming apparatus according to the present invention includes the sheet conveying device.

  With this configuration, it is possible to reduce damage to the sheet and the sheet suction conveyance unit in the image forming apparatus including the sheet conveyance device.

  The image forming apparatus according to the present invention is a digital copier.

  With this configuration, in the image forming apparatus as a digital copying machine, it is possible to reduce damage to the sheet and the sheet suction conveyance unit.

  The image forming apparatus according to the present invention is a printer device.

  With this configuration, in the image forming apparatus as a printer apparatus, it is possible to reduce damage to the sheet and the sheet suction conveyance unit.

  The image forming apparatus according to the present invention is a facsimile machine.

  With this configuration, in the image forming apparatus as a facsimile apparatus, it is possible to reduce damage to the sheet and the sheet suction conveyance unit.

  The image forming apparatus according to the present invention is an offset printing machine.

  With this configuration, in the image forming apparatus as an offset printing machine, it is possible to reduce damage to the sheet and the sheet suction conveyance unit.

  ADVANTAGE OF THE INVENTION According to this invention, the sheet | seat conveying apparatus and image forming apparatus which can reduce the damage of a sheet | seat and a sheet | seat adsorption | suction conveyance means can be provided.

1 is a schematic configuration diagram of an image forming apparatus including a sheet conveying device according to an embodiment of the present invention. It is sectional drawing of the sheet conveying apparatus which concerns on one embodiment of this invention. FIG. 6 is a cross-sectional view illustrating a sheet conveying operation of a sheet conveying apparatus according to an embodiment of the present invention. It is sectional drawing from the arrow Z direction of FIG. 3 of the sheet conveying apparatus which concerns on one embodiment of this invention. It is a block diagram which shows the control means of the sheet conveying apparatus which concerns on one embodiment of this invention. FIG. 6 is an enlarged cross-sectional view illustrating a sheet conveying operation when a sheet suction conveying belt of the sheet conveying apparatus according to the embodiment of the present invention is rotated. It is an expanded sectional view from the arrow Z direction of FIG. 6 of the sheet conveying apparatus which concerns on one embodiment of this invention. FIG. 6 is an enlarged cross-sectional view for explaining a sheet conveying operation when the sheet suction conveying belt of the sheet conveying apparatus according to the embodiment of the present invention is stopped. It is an expanded sectional view from the arrow Z direction of FIG. 8 of the sheet conveying apparatus which concerns on one embodiment of this invention. It is a schematic sectional drawing which shows an example of the conventional sheet conveying apparatus. It is a figure explaining operation | movement of the sheet conveying apparatus of FIG.

  Embodiments of the present invention will be described below with reference to the drawings.

  First, the configuration will be described.

  As shown in FIG. 1, the image forming apparatus 51 is configured as an electrophotographic digital copier, and includes an original reading unit 52 that reads an original and an uppermost sheet (recording paper) conveyed from the sheet conveying apparatus 1. An image forming unit 53 that forms an image read by the document reading unit 52 with respect to 2A, and a sheet conveying apparatus 1 that separates one uppermost sheet 2A from the sheet bundle 2 and conveys the image to the image forming unit 53. Yes.

  The uppermost sheet 2A conveyed by the sheet conveying device 1 is conveyed by a conveying roller pair 58, and the toner image formed by the image forming unit 53 is transferred by the transfer device 59. The toner image is thermally transferred by the fixing device 60. The paper discharge roller pair 61 discharges the paper to the paper discharge tray 62.

  Hereinafter, the details of the sheet conveying apparatus 1 will be described with reference to FIGS.

  2 to 4, the sheet conveying apparatus 1 includes a sheet storage unit 11, a sheet suction conveying unit 12, an air suction unit 13, an air blowing unit 14, a driving unit 17, and a sheet lifting / lowering unit 18. And. Further, as shown in FIG. 5, the sheet conveying apparatus 1 includes a control unit 19 that controls an air suction unit 13, an air blowing unit 14, a driving unit 17, and a sheet lifting / lowering unit 18.

  The sheet storage unit 11 includes a stacking tray 11A that is a horizontal plane, and stores a plurality of sheet bundles 2 stacked on the stacking tray 11A. The sheet storage unit 11 is connected to a sheet lifting / lowering unit 18 connected to the control unit 19, and when the sheet lifting / lowering unit 18 is driven, the stacking tray 11 </ b> A moves up and down, and the sheet bundle 2 in the sheet storage unit 11. Is configured to be able to move up and down. The sheet elevating means 18 includes a stepping motor and a servo motor with an encoder so that the stacking tray 11A can be raised by an arbitrary amount.

  The sheet suction conveyance unit 12 is drivingly connected to a drive unit 17 connected to the control unit 19, and includes a sheet suction conveyance belt 12C that spans two rollers 12A and 12B. As shown in FIG. 4, a large number of suction holes 12 </ b> D are formed in the entire sheet suction conveyance belt 12 </ b> C, and air is sucked from the suction holes 12 </ b> D into the inner space of the sheet suction conveyance belt 12 </ b> C. An air suction part 13 is provided.

  One end of a suction duct 13 </ b> A is connected to the air suction unit 13. A suction fan 13C is provided at the other end of the suction duct 13A. The suction duct 13A is provided with a suction duct opening / closing part 13B.

  The suction fan 13C is connected to the control means 19, and the suction fan 13C is rotated by the control of the control means 19 and sucks air from the suction hole 12D. 11, the uppermost sheet 2A positioned at the top in the vertical direction is separated by being adsorbed to the sheet adsorbing and conveying belt 12C one by one, and the uppermost sheet 2A is adsorbed. The driving unit 17 is driven by the control of the control unit 19 and the sheet suction conveyance belt 12C rotates, so that the uppermost sheet 2A is conveyed from the sheet conveyance device 1 to the inside of the image forming apparatus 51.

  The suction duct opening / closing part 13B is connected to the control means 19, and when the suction duct opening / closing part 13B is opened by the control of the control means 19, the suction pressure by the suction fan 13C escapes, that is, the negative pressure in the suction duct 13A is reduced. As a result, the air adsorption force from the suction hole 12D is reduced.

  The sheet bundle 2 is defined by a pair of sides composed of a first side 2B and a second side 2C, and a pair of sides composed of a third side 2D and a fourth side 2E (FIG. 4). It has a rectangular shape. The third side 2D and the fourth side 2E are arranged so as to be in the direction connecting the two rollers 12A and 12B of the sheet suction conveyance unit 12, respectively. The first side 2B is the right end in FIG. The second side 2C is located on the downstream side in the sheet conveying direction at the left end in FIG.

  As shown in FIG. 3, the air blower 14 is provided at a position near the first side 2 </ b> B of the uppermost sheet 2 </ b> A and facing the first side 2 </ b> B, and is connected to the control means 19. Has been. The air blower 14 floats the uppermost sheet 2A and the sheet in the vicinity of the first side 2B of the uppermost sheet 2A by blowing air to the sheet bundle 2, and a plurality of sheets including the uppermost sheet 2A. Are separated from each other.

  In the present embodiment, the air blowing unit 14 is disposed only at a position facing the first side 2B. However, the air blowing unit 14 is opposed to the third side 2D and the fourth side 2E. You may arrange in a position. Further, the control means 19 is connected to the uppermost sheet position detection means (not shown) for detecting the vertical position of the uppermost sheet 2A of the sheet bundle 2, and the control means is based on the vertical position of the uppermost sheet 2A. 19 controls the sheet elevating means 18 so that the sheet bundle 2 rises to the vertical position optimal for the suction of the uppermost sheet 2A by the air suction unit 13, and controls the drive unit 17 that rotates the sheet suction conveyance belt 12C. It is supposed to be.

  As shown in FIG. 6, after the sheet adsorption / conveyance belt 12C adsorbs the uppermost sheet 2A, the sheet adsorption / conveyance belt 12C is driven to convey the uppermost sheet 2A. At this time, as shown in FIG. 7, the suction fan 13C rotates and the suction duct opening / closing part 13B is closed, so that the sheet suction conveyance belt 12C sucks the uppermost sheet 2A.

  As shown in FIG. 8, after the uppermost sheet 2A adsorbed and conveyed by the sheet adsorbing and conveying belt 12C reaches a predetermined position (a position where the leading end of the uppermost sheet 2A is sandwiched by the downstream sheet conveying means 21). The rotation of the sheet adsorption / conveyance belt 12C is stopped by a command from the control means 19, and the uppermost sheet 2A is conveyed by the rotation of the downstream sheet conveyance means 21. That is, when the leading edge of the uppermost sheet 2A reaches the downstream sheet conveying means 21, the conveyance of the uppermost sheet 2A is taken over from the sheet adsorption conveying belt 12C to the downstream sheet conveying means 21.

  Note that the fact that the leading edge of the uppermost sheet 2A has reached the position where it is sandwiched between the downstream sheet conveying means 21 detects, for example, the rotation amount of the sheet suction conveying belt 12C, or the sheet of the downstream sheet conveying means 21 Detection is possible by providing a sheet detection sensor in the immediate vicinity of the upstream side in the conveyance direction. Further, before the leading edge of the uppermost sheet 2A reaches the position sandwiched between the downstream sheet conveying means 21, the downstream sheet conveying means 21 may be rotating or may be stopped. That is, even if the downstream sheet conveying means 21 is always rotating, the downstream sheet conveying means 21 starts rotating immediately before the leading edge of the uppermost sheet 2A reaches the position sandwiched between the downstream sheet conveying means 21. May be.

  In the state of FIG. 8, if the sheet suction conveyance belt 12C remains sucking the uppermost sheet 2A, a large frictional force is generated between the uppermost sheet 2A and the sheet suction conveyance belt 12C, and the uppermost sheet 2A. Rubs against the sheet adsorbing and conveying belt 12C, so that the sheet adsorbing and conveying belt 12C may be worn out or the uppermost sheet 2A may be damaged. That is, there is a possibility that the sheet adsorption conveyance belt 12C and the uppermost sheet 2A are damaged.

  Therefore, in the present embodiment, the controller 19 adsorbs and conveys the uppermost sheet 2A by the sheet adsorbing and conveying belt 12C, and when the leading end of the uppermost sheet 2A reaches the downstream sheet conveying means 21, FIG. As shown, the suction duct opening / closing part 13B is opened to reduce the suction force of the uppermost sheet 2A by the sheet suction conveyance belt 12C. When the uppermost sheet 2A is conveyed by the rotation of the downstream sheet conveying unit 21, the adsorption force by the sheet adsorption conveyance belt 12C may be reduced to zero.

  Further, when the rear end of the uppermost sheet 2A is separated from the sheet suction conveyance belt 12C, the control unit 19 closes the suction duct opening / closing part 13B and conveys the next sheet of the uppermost sheet 2A by the sheet adsorption conveyance belt 12C. Because of this, the suction force is restored. The control means 19 repeats such opening and closing of the suction duct every time the sheet is conveyed.

  As a result, when the sheet adsorption / conveyance belt 12C adsorbs and conveys the uppermost sheet 2A, the frictional force between the sheet adsorption / conveyance belt 12C and the uppermost sheet 2A is large, and the uppermost sheet is fed from the sheet adsorption / conveyance belt 12C. When 2A is pulled out, the frictional force between the sheet suction conveyance belt 12C and the uppermost sheet 2A is reduced.

  Accordingly, it is possible to reduce the frictional force when the uppermost sheet 2A is pulled out while ensuring the conveyance force by the sheet adsorption conveyance belt 12C, and to reduce damage to the uppermost sheet 2A and the sheet adsorption conveyance belt 12C. it can.

  In order to reduce the suction force of the uppermost sheet 2A by the sheet suction conveyance belt 12C, the rotation of the suction fan 13C may be reduced or stopped. In this case, the rotation of the suction fan 13C is changed. There is a possibility that the responsiveness of the increase / decrease of the suction force with respect to may deteriorate. Therefore, as in the present embodiment, the configuration in which the suction duct opening / closing portion 13B is opened to reduce the suction force of the uppermost sheet 2A by the sheet suction conveyance belt 12C is excellent in responsiveness.

  The operation of the sheet conveying apparatus 1 configured as described above will be described.

  In the sheet conveying apparatus 1, as shown in FIGS. 6 and 7, the control means 19 generates an adsorption force on the sheet adsorption conveyance belt 12C to adsorb the uppermost sheet 2A, and rotates the sheet adsorption conveyance belt 12C. It rotates to convey the uppermost sheet 2A. 6 and 7, the sucked sheet is already in contact with the sheet suction conveyance belt 12C.

  Next, as shown in FIGS. 8 and 9, the control unit 19 stops the rotation of the sheet suction conveyance belt 12 </ b> C when the leading edge of the uppermost sheet 2 </ b> A reaches the downstream sheet conveyance unit 21, and the downstream sheet conveyance unit 21. Thus, the uppermost sheet 2A is conveyed.

  Further, the control means 19 opens the suction duct opening / closing part 13B to reduce the suction pressure of air from the suction hole 12D (see FIG. 4). As a result, the contact pressure between the uppermost sheet 2A and the sheet adsorption conveyance belt 12C decreases.

  By opening the suction duct opening / closing part 13B, the contact pressure between the uppermost sheet 2A and the sheet adsorption / conveyance belt 12C is reduced, so that the friction between the uppermost sheet 2A and the sheet adsorption / conveyance belt 12C is reduced, and the friction Can prevent the uppermost sheet 2A from being damaged, and can reduce the wear of the sheet adsorbing and conveying belt 12C.

  Further, the image forming apparatus 51 is not limited to an electrophotographic digital copier, and may be another type of digital copier such as an ink jet system. Further, the image forming apparatus 51 is not limited to a digital copying machine, and may be configured as a printer apparatus, a facsimile apparatus, or an offset printing machine.

  As described above, the sheet conveying apparatus 1 according to the present embodiment has the sheet storage unit 11 that stacks and stores the sheet bundle 2 on the stacking tray 11A, and the sheet stack 2 stacked on the stacking tray 11A in the vertical direction. The sheet raising / lowering means 18 that moves up and down and the sheet bundle 2 raised by the sheet raising / lowering means 18 are blown from the downstream side in the sheet conveying direction, and the uppermost sheet including at least the uppermost sheet 2A of the sheet bundle 2 is levitated. The air blowing unit 14 that separates the sheets, the sheet suction conveying unit 12 that sucks and conveys the uppermost sheet 2 </ b> A floated by the air blowing unit 14, one end is connected to the inside of the sheet adsorption conveying unit 12, and the like A suction duct 13A provided with a suction fan 13C for generating the suction force of the sheet suction conveyance means 12 at the end, and a suction duct 13A provided at the time of opening. An air suction unit 13 having a suction duct opening / closing unit 13B that opens the drawing duct 13A to the outside air, and the uppermost sheet that is provided downstream of the sheet suction conveyance unit 12 in the sheet conveyance direction and is conveyed by the sheet adsorption conveyance unit 12 When the uppermost sheet 2A is adsorbed and conveyed by the downstream sheet conveying means 21 that further conveys 2A and the sheet suction conveying means 12, and the leading end of the uppermost sheet 2A reaches the downstream sheet conveying means 21, the suction duct is opened and closed. And a control unit 19 that opens the portion 13B and reduces the adsorption force of the uppermost sheet 2A by the sheet adsorption conveyance unit 12.

  With this configuration, when the uppermost sheet 2A is conveyed by the downstream sheet conveying means 21, friction between the uppermost sheet 2A and the sheet suction conveying means 12 is reduced, and damage to the uppermost sheet 2A due to friction is reduced. While being able to prevent, abrasion of the sheet | seat adsorption | suction conveyance means 12 can be reduced. Therefore, damage to the sheet and the sheet suction conveyance unit 12 can be reduced.

  In the sheet conveying apparatus 1 according to the present embodiment, the control unit 19 adsorbs and conveys the uppermost sheet 2A by the sheet adsorbing and conveying unit 12, and the downstream sheet conveying unit 21 has the leading end of the uppermost sheet 2A. When reaching, the suction duct opening / closing part 13B is opened, and when the rear end of the uppermost sheet 2A is separated from the sheet suction conveyance means 12, the suction duct opening / closing part 13B is closed.

  With this configuration, damage to the sheet and the sheet suction conveyance unit 12 can be reduced.

  Further, the sheet conveying apparatus 1 according to the present embodiment is characterized in that the suction duct opening / closing part 13B is repeatedly opened and closed every sheet conveyance.

  With this configuration, damage to the sheet and the sheet suction conveyance unit 12 can be reduced.

  The image forming apparatus 51 according to the present embodiment includes the sheet conveying apparatus 1 described above.

  With this configuration, in the image forming apparatus 51 including the sheet conveying apparatus 1, damage to the uppermost sheet 2A and the sheet suction conveying belt 12C can be reduced.

  The image forming apparatus 51 according to the present embodiment is a digital copier.

  For this reason, in the image forming apparatus 51 as a digital copying machine, it is possible to reduce damage to the uppermost sheet 2A and the sheet suction conveyance belt 12C.

  The image forming apparatus 51 according to the present embodiment is a printer apparatus.

  For this reason, in the image forming apparatus 51 as a printer apparatus, damage to the uppermost sheet 2A and the sheet suction conveyance belt 12C can be reduced.

  The image forming apparatus 51 according to the present embodiment is a facsimile machine.

  For this reason, in the image forming apparatus 51 as a facsimile apparatus, damage to the uppermost sheet 2A and the sheet suction conveyance belt 12C can be reduced.

  The image forming apparatus 51 according to the present embodiment is an offset printing machine.

  For this reason, in the image forming apparatus 51 as an offset printing machine, damage to the uppermost sheet 2A and the sheet suction conveyance belt 12C can be reduced.

  As described above, the sheet conveying apparatus and the image forming apparatus according to the present invention have an effect that the damage of the sheet and the sheet suction conveying unit can be reduced, and the uppermost sheet is separated from the sheet bundle by air suction. Thus, it is useful as a sheet conveying apparatus that conveys the sheet and an image forming apparatus including the sheet conveying apparatus.

DESCRIPTION OF SYMBOLS 1 Sheet conveying apparatus 2 Sheet bundle 2A Topmost sheet 11 Sheet storage part 11A Stack tray 12 Sheet adsorption conveyance means 12A, 12B Roller 12C Sheet adsorption conveyance belt 12D Suction hole 13 Air suction part (air suction means)
13A Suction duct 13B Suction duct opening / closing section 13C Suction fan 14 Air blowing section 17 Drive section 18 Sheet lifting / lowering means 19 Control means 21 Downstream sheet conveying means 51 Image forming apparatus

JP-A-11-79441

Claims (8)

A sheet storage unit for stacking and storing sheet bundles on a stacking tray;
Sheet elevating means for elevating and lowering a bundle of sheets stacked on the stacking tray in a vertical direction;
An air blowing unit that blows air from the downstream side in the sheet conveying direction with respect to the sheet bundle raised by the sheet elevating unit, and floats the upper sheet including at least the uppermost sheet of the sheet bundle to separate the sheets. When,
Sheet adsorbing and conveying means for adsorbing and conveying the uppermost sheet levitated by the air blowing unit;
A suction duct having one end connected to the inside of the sheet suction conveyance means and a suction fan for generating the suction force of the sheet suction conveyance means at the other end, and the suction duct provided in the suction duct when opened. An air suction means having a suction duct opening and closing part that opens to the outside air;
A downstream sheet conveying means provided on the downstream side of the sheet adsorption conveying means in the sheet conveying direction, further conveying the uppermost sheet conveyed by the sheet adsorption conveying means;
The uppermost sheet is adsorbed and conveyed by the sheet adsorbing / conveying means, and when the leading end of the uppermost sheet reaches the downstream sheet conveying means, the suction duct opening / closing part is opened and the sheet adsorbing / conveying means And a control means for reducing the suction force of the uppermost sheet.   The control means adsorbs and conveys the uppermost sheet by the sheet adsorbing and conveying means, and when the leading end of the uppermost sheet reaches the downstream sheet conveying means, opens the suction duct opening and closing unit, 2. The sheet conveying apparatus according to claim 1, wherein when the rear end of the uppermost sheet is separated from the suction conveying means, the suction duct opening / closing part is closed.   The sheet conveying apparatus according to claim 2, wherein the control unit repeats opening and closing of the suction duct opening and closing unit for each sheet conveyance.   An image forming apparatus comprising the sheet conveying device according to claim 1.   The image forming apparatus according to claim 4, wherein the image forming apparatus is a digital copier.   The image forming apparatus according to claim 4, wherein the image forming apparatus is a printer apparatus.   The image forming apparatus according to claim 4, wherein the image forming apparatus is a facsimile apparatus.   The image forming apparatus according to claim 4, wherein the image forming apparatus is an offset printing machine.

Images