JP2014062000A - Sheet conveying device, and image formation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent air from staying between an uppermost sheet and an attraction surface of an electrostatic attraction belt to stably attract the uppermost sheet to the electrostatic attraction belt.SOLUTION: A sheet conveying device 10 separates an uppermost sheet 1A from a sheet bundle 1 and conveys the sheet. The sheet conveying device includes: a sheet storage part 11 for storing the sheet bundle 1; a sheet lifting component 12 for vertically lifting the sheet bundle 1; an electrostatic attraction belt unit 13 for electrostatically attracting the uppermost sheet 1A, which is located above the sheet bundle 1 and composed of two endless electrostatic attraction belts 13A and 13A arranged so as to have a space K between them; and an air blowing part 14 for floating the uppermost sheet and sheets under the uppermost sheet to separate the uppermost sheet by blowing air toward the space between the electrostatic attraction belts from below a position of attraction surfaces of the electrostatic attraction belts at a position in the vicinity of the uppermost sheet 1A of the sheet bundle 1 stored in the storing part 11.

Description

  The present invention relates to a sheet conveying apparatus used for an image forming apparatus such as a facsimile, a printer, a copying machine, a multifunction machine having at least two of these functions using an electrophotographic system, an electrostatic recording system, and the like, and an image provided with the same. The present invention relates to a forming apparatus.

  As a sheet conveying apparatus used in an image forming apparatus such as a copying machine or a printer, an air suction type sheet conveying apparatus shown in FIG. 25 is widely known (see Patent Document 1).

  A sheet conveying apparatus 101 shown in FIG. 25 is provided with a sheet adsorbing / conveying unit 112 including a sheet feeding belt 112C above the sheet storing unit 111, and includes a plurality of sheets stacked on the sheet storing unit 111. The sheet 102A at the top of the sheet bundle 102 in the vertical direction (hereinafter referred to as “uppermost sheet 102A”) is attracted to the sheet feeding belt 112C one by one by the air suction unit 113, and the uppermost sheet 102A is moved to a predetermined position. It is comprised so that it may convey. An air blowing unit 114 is provided on the downstream side of the sheet storage unit 111, and the stacked sheet bundle 102 is separated by blowing air to one end of the sheet bundle 102.

  A downstream uppermost sheet detection unit 115 is provided on the downstream side of the sheet conveyance, and an upstream uppermost sheet detection unit 116 is provided on the upstream side of the sheet conveyance that is not affected by the lift of the sheet by the air blower 114. ing. The upstream uppermost sheet detection means 116 includes a position detection unit 116A and a position detection lever 116B. The sheet storage unit 111 is connected to the sheet lifting / lowering means 118 and can be lifted / lowered. When the uppermost sheet 102A comes into contact with the position detection lever 116B, the position detection lever 116B is configured to be pushed vertically upward. A large number of suction holes (not shown) are formed on the entire surface of the paper feed belt 112C. The uppermost sheet 102A is adsorbed to the paper feed belt 112C via the suction holes and the air suction unit 113, and Transport.

  The sheet conveying operation with the above configuration is as follows. First, before the sheet conveying operation is started, the sheet elevating member 111A is raised by the sheet elevating unit 118, and the downstream end of the uppermost sheet 102A of the stacked sheets 102 is detected by the downstream uppermost sheet detecting unit 115. The detection position of the uppermost sheet 102A is stored in the upstream uppermost sheet detection means 116 as a reference position.

  Next, as shown in FIG. 26, the separation air A is blown to the sheets 102 stacked by the air blowing unit 114, and the stacked sheet bundles 102 are separated. The uppermost sheet 102A is attracted to the sheet feeding belt 112C by the air suction unit 113, the sheet feeding belt 112C is rotated, and the attracted sheet is conveyed to a predetermined position. When the sheet 102 in the sheet storage unit 111 is reduced by sheet conveyance, the vertical position of the uppermost sheet 102A is lowered, and the upstream uppermost sheet detection unit 116 is out of the reference position stored, the sheet lifting unit 118 raises the sheet. Let When the vertical position of the uppermost sheet 102A is not lowered so much and the upstream uppermost sheet detecting means 116 is detecting the reference position, the sheet conveying operation is continued.

  Many air suction-type sheet conveying apparatuses as described above are known, but as described in the examples shown in FIGS. 18 and 19, all of them are negative pressure by sucking the air suction part 113 to make a vacuum state. Is generated, and the uppermost sheet 102A is adsorbed to the sheet feeding belt 112C. Therefore, it is considered that the sheet surface is damaged by an excessive negative pressure. May be transferred.

  That is, in the case of air adsorption, since the adsorption force is strong, even if the separation air A is blown toward the belt from the downstream side, there is no problem that the uppermost sheet peels off, and the second and subsequent sheets can be reliably pushed down. However, since air suction has a strong suction force and damages the sheet, a method using an electrostatic suction belt that electrostatically attracts with a weaker suction force has been proposed.

  Since the sheet conveying apparatus using the electrostatic adsorption belt uses an electrostatic adsorption force (Coulomb force) for the uppermost sheet adsorption, there is no damage to the sheet surface unlike the air suction type adsorption system.

  However, in order to separate the sheets, an air blowing unit is provided in the electrostatic adsorption type sheet conveying device, and when air is blown to separate the sheets, air is generated between the uppermost sheet and the adsorption surface of the electrostatic adsorption belt. There is a problem that the top sheet cannot be stably adsorbed.

  The present invention has been made in view of the above points. Air does not accumulate between the uppermost sheet to be conveyed and the electrostatic adsorption belt, and the uppermost sheet can be stably adsorbed to the electrostatic adsorption belt. It is an object to provide a sheet conveying device and an image forming apparatus.

  A sheet conveying apparatus according to the present invention includes a sheet storage unit that stores a sheet bundle, a sheet elevating unit that vertically moves the sheet bundle, and an endless unit that is positioned above the sheet bundle and electrostatically attracts the uppermost sheet. An electrostatic attraction belt device in which a plurality of electrostatic attraction belts are arranged with a gap between each other, and a position near the uppermost sheet of the sheet bundle stored in the sheet storage portion, An air blower that levitates the uppermost sheet and the lower sheet from the uppermost sheet and separates the uppermost sheet by blowing air toward the gap between the electrostatic adsorption belts from below the position. It is characterized by.

  According to the present invention, the air from the air blowing section is allowed to pass through the gap between the electrostatic adsorption belts, thereby preventing the uppermost sheet and the adsorption surface of the electrostatic adsorption belt from accumulating. It can be stably adsorbed to the electrostatic attraction belt.

1 is a schematic configuration diagram illustrating an example of an image forming apparatus that can be equipped with a sheet conveying apparatus according to the present invention. 1 is a side view illustrating a sheet conveying apparatus according to a first embodiment of a sheet conveying apparatus according to the present invention. It is a top view which shows the same sheet conveying apparatus. FIG. 2 shows a state of air in the sheet conveying apparatus, (a) is a schematic diagram showing a case where an air reflecting plate is not provided, and (b), (c) is a schematic diagram showing a case where an air reflecting plate is provided. is there. The sheet conveyance state in the sheet conveying apparatus is shown, and (a) and (b) are schematic views sequentially illustrating the conveyance state. FIG. 1 shows an electrode-embedded electrostatic chucking belt of a sheet conveying apparatus, (a) is a schematic diagram showing the configuration, and (b) is a position of an exhaust hole provided on the chucking surface of the electrostatic chucking belt with respect to the uppermost sheet. It is a schematic diagram which shows. The figure which shows the table which showed the combination of the distance and the air quantity according to sheet basis weight and sheet size with respect to different kinds of sheets of non-coated paper represented by high-quality paper and coated paper represented by coated paper It is. FIG. 3 shows an arrangement state of an electrostatic attraction belt of a sheet conveying apparatus according to Embodiment 2 of a sheet conveying apparatus according to the present invention, (a) is a schematic diagram showing a first state, and (b) is a second figure. The schematic diagram which shows a state, (c) is a schematic diagram which shows a driving force transmission mechanism. FIG. 7 shows positions of a driving roller and a driven roller of a sheet conveying apparatus according to Embodiment 3 of the sheet conveying apparatus according to the present invention, (a) is a schematic diagram showing an adsorption position, and (b) is a schematic showing a conveying position. FIG. FIG. 7 shows a sheet conveying apparatus according to Embodiment 4 of the sheet conveying apparatus according to the present invention, wherein (a) and (b) are schematic views showing the operation of the first air blowing unit, and (c) is a second figure. It is a schematic diagram which shows operation | movement of an air ventilation part. It is a top view which shows the same sheet conveying apparatus. The air blowing state of the sheet conveying apparatus is viewed from the Z direction in FIG. 10, and (a) and (b) are schematic views sequentially illustrating the conveying operation of the sheet conveying apparatus. FIG. 2 shows a blowing angle from an air blowing unit of the sheet conveying apparatus, (a) is a schematic diagram showing an air blowing state, and (b) is a table showing an air blowing angle. The figure which shows the table which showed the combination of the distance and the air quantity according to sheet basis weight and sheet size with respect to different kinds of sheets of non-coated paper represented by high-quality paper and coated paper represented by coated paper It is. It is a side view which shows the sheet conveying apparatus which concerns on Embodiment 5 of the sheet conveying apparatus which concerns on this invention. It shows the action of the conveyance guide plate of the sheet conveying apparatus, (a) is a view showing the state of adsorbing and conveying the uppermost sheet from the right side of FIG. FIG. 6 is an enlarged view showing a state in which a part of air acts as pushed-down air that is reflected downward from the lower surface of the sheet in the conveyance guide plate and flows downward. It shows another example of the conveyance guide plate of the sheet conveyance device, (a) is a diagram showing an example of forming a vent hole of the conveyance guide plate, (b) is a diagram showing the shape and position of the conveyance guide plate. is there. The sheet conveying apparatus which concerns on Embodiment 6 of the sheet conveying apparatus which concerns on this invention is shown, (a) is a front view, (b) is an arrow view from the A direction in (a). The operation | movement of the sheet conveying apparatus is shown, (a) is a side view, (b) is an arrow view from the A direction in (a). The operation | movement of the sheet conveying apparatus is shown, (a) is a side view, (b) is an arrow view from the A direction in (a). 6 is a flowchart illustrating an operation of the sheet conveying apparatus. The sheet conveying apparatus which concerns on Embodiment 7 of the sheet conveying apparatus which concerns on this invention is shown, (a) is a side view, (b) is an arrow view from the A direction in (a). The operation | movement of the sheet conveying apparatus is shown, (a) is a side view, (b) is an arrow view from the A direction in (a). The operation | movement of the sheet conveying apparatus is shown, (a) is a side view, (b) is an arrow view from the A direction in (a). It is a schematic diagram which shows an example of the conventional air suction type sheet conveying apparatus. FIG. 26 is a schematic diagram illustrating an operation state of the sheet conveying apparatus illustrated in FIG. 25.

  A sheet conveying apparatus and an image forming apparatus according to an embodiment for carrying out the present invention will be described.

  FIG. 1 is a schematic configuration diagram showing an example of an image forming apparatus that can be equipped with a sheet conveying apparatus according to the present invention. Note that the image forming apparatus to be implemented in the present invention is not limited to the one shown in the figure, and the image forming apparatus such as a copying machine, a facsimile apparatus, an apparatus having a function of a multifunction machine having a copying function and a facsimile function, etc. Various devices that perform the above are targeted.

  In FIG. 1, a copying machine 100 as an example of an image forming apparatus separates a document from a bundle of documents placed on a document tray 110a and automatically feeds the document to a contact glass on a document reading unit 120. 110. Further, the copying machine 100 includes a document reading unit 120 that reads a document conveyed on the contact glass by the automatic document conveyance device 110 and an image forming unit (image forming unit) 140. The image forming unit 140 performs an image forming process on the sheet material fed from the paper feeding unit 130 and forms an image read by the document reading unit 120. Further, the copying machine 100 includes a sheet feeding unit 130 that feeds the uppermost sheet 1A positioned from the sheet bundle 1 to the image forming unit 140. In this embodiment, the image forming unit 140 and the paper feeding unit 130 can be divided, but a configuration other than that may be used.

  The sheet feeding unit 130 includes a sheet feeding cassette 150 that stacks a sheet bundle 1 composed of a plurality of sheets, and a sheet separation sheet feeding device 160 that separates and conveys the uppermost sheet 1A from the sheet bundle 1 on the sheet feeding cassette 150. Is included.

  The sheets separated and fed by the sheet separating and feeding device 160 are conveyed on the conveyance path 170. The sheet conveyed on the conveyance path 170 is conveyed by a conveyance roller pair 180, and the toner image formed by the image forming unit 140 is transferred by the transfer roller 190. Further, the toner image transferred to the sheet is thermally fixed by the fixing device 200, and the sheet is discharged to the discharge tray 220 by the discharge roller pair 210.

  The image forming unit 140 includes four image forming units 230 (230Y (yellow), 230C (cyan), 230M (magenta), 230BK (black)), an intermediate transfer belt 240 that is a transfer belt, and an exposure device 250. It is configured.

  The exposure device 250 converts image data into a signal for driving a light source, and drives a semiconductor laser in each laser light source unit accordingly to emit a light beam. As the image data, color-separated image data input from a personal computer, a word processor, or the like, or a document read by the document reading unit 120 is used.

  The image forming units 230Y, 230C, 230M, and 230BK form images of different colors (toner images). The image forming units 230Y, 230C, 230M, and 230BK are a photoconductor 260 (260Y, 260C, 260M, and 260BK) that is an image carrier that is driven to rotate in a clockwise direction, and a charging unit 270 that is disposed around the photoconductor 260. , A developing unit 280, a cleaning unit 290, and the like.

  The photoreceptor 260 is formed in a cylindrical shape and is driven to rotate by a drive source (not shown). A photosensitive layer is provided on the outer peripheral surface portion of the photoconductor 260, and a light beam indicated by a broken line emitted from the exposure apparatus 250 is spot-irradiated on the outer peripheral surface of the photoconductor 260, whereby the outer peripheral surface of the photoconductor 260 is exposed. The electrostatic latent image corresponding to the image information is written.

  The charging unit 270 uniformly charges the outer peripheral surface of the photoconductor 260, and a contact type is used for the photoconductor 260. The developing unit 280 supplies toner to the photosensitive member 260, and the supplied toner adheres to the electrostatic latent image written on the outer peripheral surface of the photosensitive member 260, whereby the electrostatic latent image on the photosensitive member 260 is changed. It is visualized as a toner image. A non-contact type is used for the photoreceptor 260.

The cleaning unit 290 cleans residual toner adhering to the outer peripheral surface of the photoconductor 260 and employs a brush contact type in which a brush contacts the outer peripheral surface of the photoconductor 260.

  The intermediate transfer belt 240 is composed of an endless belt formed using a resin film or rubber as a base, and the toner image formed on the photosensitive member 260 is transferred to the intermediate transfer belt 240. The toner image is transferred onto the sheet by the transfer roller 190.

<Embodiment 1>
Next, the sheet conveying apparatus will be described. 2 is a side view showing the sheet conveying apparatus according to the first embodiment of the sheet conveying apparatus according to the present invention, FIG. 3 is a plan view showing the sheet conveying apparatus, and FIG. 4 is an arrangement of the electrostatic adsorption belt of the sheet conveying apparatus. It is a schematic diagram which shows a state.

  As shown in FIG. 2, the sheet conveying apparatus 10 includes a sheet storage unit 11, a sheet elevating member 12 that is a sheet elevating unit, an electrostatic adsorption belt device 13, a protruding member 13 </ b> F, an air blowing unit 14, The suction belt driving unit 13E, the sheet lifting member driving unit 18, the conveyance direction side end regulating members 15A and 15B of the sheet bundle 1 shown in FIG. 6, the control unit 19, and the air reflecting plate 20 are provided.

  The sheet elevating member 12 includes a bottom surface portion 12A disposed horizontally, and a sheet bundle 1 composed of a plurality of sheets stacked on the bottom surface portion 12A can be stacked. In the sheet storage unit 11, the drive is controlled by the control unit 19, and the sheet lifting member driving unit 18 drives the sheet lifting member 12 up and down. By driving the sheet elevating member driving means 18, the sheet elevating member 12 is raised and lowered, and the sheet bundle 1 in the sheet storage unit 11 can be raised and lowered.

  As shown in FIG. 3, the electrostatic adsorption belt device 13 includes a plurality of electrostatic adsorption belt units 131 and 132 in this example. Each of the electrostatic attraction belt units 131 and 132 is configured by winding the electrostatic attraction belt 13A around the driving roller 13B and the driven roller 13C.

  The electrostatic adsorption belt units 131 and 132 are arranged so that the electrostatic adsorption belts 13A and 13A leave a gap K. In this example, the electrostatic attraction belt units 131 and 132 are fixedly arranged in the vertical direction with respect to the sheet bundle 1.

  The configuration of the electrostatic adsorption belt will be described. 6A and 6B show an electrode-embedded electrostatic chucking belt of a sheet conveying apparatus, in which FIG. 6A is a schematic diagram showing the configuration, and FIG. 6B is an exhaust provided on the suction surface of the electrostatic chucking belt with respect to the uppermost sheet. It is a schematic diagram which shows the position of a hole. The electrostatic adsorption belt 13A is a belt made of a sheet-like medium in which a plurality of electrodes 21 as shown in FIG. In the plurality of electrodes 21, positive electrodes 21A and negative electrodes 21B are alternately arranged. When a voltage is applied to these electrodes 21 by the electrostatic attraction belt power supply device 13D, dielectric polarization occurs, and the attraction surface of the uppermost sheet 1A is polarized. Therefore, an electrostatic attraction force (Coulomb force) between the electrodes 21 and the electrostatic attraction belt 13A. Occurs.

  As shown in FIGS. 4B and 4C, the uppermost sheet 1A attracted to the electrostatic attracting belt 13A by the electrostatic attracting force is attracted to the electrostatic attracting belt 13A by the electrostatic attracting belt driving means 13E. When driven and rotated, the electrostatic attraction belt 13A is configured to be conveyed to a position where image forming means (not shown) is disposed.

  Further, in this configuration, the electrostatic attraction belt 13A in which the electrode 21 is covered with the insulating layer 22 is used. However, an electrostatic attraction force may be generated by applying an electric charge on the electrostatic attraction belt. You may provide the provision means.

  As shown in FIG. 3, the air blowing section 14 is provided at a position in the vicinity of the uppermost sheet, that is, a position in the vicinity of the side 1B of the uppermost sheet 1A, and a blower opening is provided at a position facing the side 1B. For example, as shown in FIG. 6, it is provided directly below the gap K between the electrostatic attraction belt units 131 and 132, as shown in FIG. The direction and position are determined so that the air blown from the air blower 14 is directed to the gap K. At this time, as will be described later, the air reflector 20 reflects the air from the air blowing section 14 and improves the air separation efficiency. The air blower 14 can be provided with air amount changing means to change the air amount.

  By blowing air by the air blowing unit 14, the uppermost sheet 1A and the sheet in the vicinity of the side 1B of the uppermost sheet 1A are levitated to approach or come into contact with the electrostatic adsorption belt 13A. Moreover, air flows between sheets by blowing air, and a plurality of sheets can be separated from each other.

  As shown in FIGS. 4 (b) and 5 (a), the air passing through the vicinity of the suction surface passes through the gap K between the electrostatic suction belts 13A and 13A before the uppermost sheet is sucked. The uppermost sheet 1A can be favorably adsorbed to the belt 13A.

  After the uppermost sheet 1A is adsorbed, as shown in FIG. 5C, the gap K between the electrostatic attraction belts 13A and 13A is blocked by the uppermost sheet 1A, so that this air enters between the uppermost sheet 1A and the next sheet. , Separation between sheets can be performed satisfactorily. At this time, as shown in FIG. 5B, a protrusion member 13F, which will be described later, forms a gap between the uppermost sheet 1A and the next sheet, and helps to separate them.

  In addition, in this structure, although the air ventilation part 14 was arrange | positioned only in the position facing the edge | side 1B, it can arrange | position to the position where the edge | side 1D and the edge | side 1E oppose in one place or multiple places.

  The air reflector 20 is disposed on the 14 side of the gap K. As shown in FIG. 4C, the air reflector 20 receives a part of the air blown from the air blower 14 and efficiently separates the uppermost sheet 1A.

  Here, the operation of the air reflector 20 will be described. In the configuration in which air from the air blowing unit 14 is blown into the gap K of the electrostatic adsorption belt 13A and the uppermost sheet 1A is adsorbed by the electrostatic adsorption belts 13A and 13A, the adsorbed uppermost sheet closes the gap K of the electrostatic adsorption belt. It will be. At this time, the air blowing unit 14 for blowing air toward the gap K between the electrostatic adsorption belts 13A and 13A is installed at a position where the adsorbed uppermost sheet 1A is pushed up from below. However, at this position, as shown in FIG. 4 (a), the floating sheet lower than the uppermost sheet 1A is also pushed up, so that the sheet floating action increases.

  The thinner the sheet, the stronger this tendency. The air separation between the uppermost sheet 1A and the sheet lower than the uppermost sheet 1A after the adsorption of the uppermost sheet 1A is inferior to this levitation action, and the separation can be performed well. There is a problem that it leads to double feeding.

  In order to solve this, it is necessary to install the air blower 14 in a position as far as possible from the sheet bundle 1 in this state to reduce the influence on the sheet bundle that is being lifted. For this reason, in the sheet conveying apparatus 10 according to the first embodiment, the air blowing unit 14 is disposed at a position apart from the air blowing unit 14 and the air reflecting plate 20 is provided in a part of the gap K between the electrostatic adsorption belts 13A and 13A. A part of the air blown by the air blowing unit 14 is applied.

  With this configuration, before adsorption of the uppermost sheet 1A, as shown in FIG. 4 (b), a part of the air blown from the air blowing unit 14 hits the air reflecting plate 20, but the air flowing upward between the belts Along the flow, air escapes to the gap K between the electrostatic adsorption belts 13A and 13A.

  Further, after the adsorption of the uppermost sheet 1A, as shown in FIG. 4C, the air flow path that has escaped through the gap K is blocked by the uppermost sheet, so that the air hitting the air reflecting plate 20 is separated from the uppermost sheet 1A. Air enters between lower sheets than the uppermost sheet 1A.

  By arranging the air blowing unit 14 and the air reflecting plate 20 in this way, the position of the air blowing unit 14 can be installed at a position further away from the sheet bundle, and the sheet of the sheet is blown by air as in the previous problem. The levitation action is no longer greater than the separation action. In addition, when the air blowing section 14 is moved away from the sheet bundle 1 and the levitation action is insufficient, one or more additional air blowing sections for levitation are added to the positions facing the sides 1B, 1D, and 1E. May be arranged.

  The air reflecting plate 20 has a gap of 0.5 mm or more from the suction surface and a gap in the opposite direction to the sheet, and the tip of the air reflecting plate 20 has a position of 1 mm or more upstream from the top of the uppermost sheet and has a length in the conveying direction. It shall be flat. As the material, a resin or the like having good sliding properties is used. However, other materials may be used as long as they do not place a burden on the sheet even if the sheet is in contact during sheet conveyance.

  As shown in FIGS. 2 and 3, the sheet bundle 1 includes a pair of sides composed of a first side 1B and a second side 1C, and a pair of sides composed of a third side 1D and a fourth side 1E. A rectangular shape defined by the sides. The side 1D and the side 1E are directed in a direction connecting the driving roller 13B and the driven roller 13C, the side 1B is located on the downstream side of the right sheet conveyance in FIG. 3, and the side 1C is the left side sheet conveyance in FIG. Located upstream.

  The protruding member 13F is disposed between the electrostatic attraction belt units 131 and 132 so as to protrude downward from the attraction surface of the electrostatic attraction belt 13A. The protruding member 13F includes a rotating member that rotates with the conveyance of the sheet in order to contact the uppermost sheet 1A when the uppermost sheet 1A is conveyed. For this reason, the resistance at the time of conveyance can be minimized, and the conveyance can be performed without damaging the uppermost sheet 1A. Further, the protruding member 13F is disposed in an area where the air from the air blower 14 can pass through the gap between the electrostatic adsorption belts 13A in a state where the uppermost sheet 1A is not floated.

  When the uppermost sheet 1A floats with air as shown in FIG. 5A and the uppermost sheet 1A covers the gap K of the electrostatic adsorption belt as shown in FIG. 1A comes into contact with the protruding member 13F and deforms. Thereby, a space is formed between the uppermost sheet 1A and the next sheet, and air enters the space, so that the uppermost sheet 1A and the next sheet can be more reliably separated.

  In addition, the protruding amount of the protruding member 13F can be changed by the protruding amount changing means 13G from the electrostatic attraction belt 13A. For example, for a sheet having a large basis weight, such as a sheet that is difficult to be deformed and attracted, the deformation of the sheet is reduced by making the protruding amount smaller than other sheet types. For this reason, the uppermost sheet 1A can be satisfactorily separated without hindering the uppermost sheet 1A from being attracted to the electrostatic attraction belt 13A.

  This protrusion member 13F can change the protrusion amount from −5 mm to 5 mm according to the sheet basis weight and size by the protrusion amount changing means 13G. For example, for a sheet having a large basis weight, the sheet is difficult to be deformed and difficult to be adsorbed, and the deformation of the sheet can be reduced by making the amount of protrusion smaller than the other sheet types, thereby preventing the adsorption to the electrostatic attraction belt 13A. In addition, separation between sheets can be performed well.

  The control unit (not shown) of the projection amount changing unit 13G is configured to adjust the electrostatic adsorption belt 13A adsorption surface at the time of adsorption of the uppermost sheet 1A according to the sheet basis weight, the sheet type, and the sheet size stacked in the sheet storage unit 11. A table for changing the distance d of the uppermost sheet 1A, the air amount e blown from the air blowing unit 14 that separates the uppermost sheet, and the air amount e blown from the air blowing unit 14 that pushes down the contact sheet is accumulated. ing.

  FIG. 7 is a table showing combinations of sheet basis weight, interval according to sheet size, and air amount for different types of sheets of non-coated paper typified by fine paper and coated paper typified by coated paper. FIG. FIGS. 7A and 7B show the uppermost sheet 1A corresponding to the sheet basis weight and sheet size for different types of sheets of non-coated paper typified by fine paper and coated paper typified by coated paper. 5 is a table showing combinations of the distance d between the electrostatic suction belt 13 </ b> A and the air amount e blown from the air blower 14. 7C and 7D are tables showing the protruding amount f of the protruding member 13F corresponding to the sheet type. In the operation of adsorbing the uppermost sheet 1A to the electrostatic attraction belt 13A in a state where the uppermost sheet 1A is floated by the air blower 14, even when the sheet basis weight, the sheet type, and the sheet size are changed, the most appropriate combination of the distance d and the air amount e By selecting the protruding amount f of the protruding member from the table, the sheet conveying operation can be performed satisfactorily.

Each table in FIG. 7 may have different values or the same values depending on the sheet basis weight, the sheet type, and the sheet size. For example, if it is a sheet conveying apparatus 10 capable of exhibiting sufficient performance at a boundary between a sheet size of less than A3 and A3 or more,
d1ax = d1bx,
d1ay = d1by,
d1az = d1bz,
e1ax = e1bx,
e1ay = e1by,
e1az = e1bz
Etc.

  In the sheet conveying apparatus 10 of the present embodiment, the uppermost sheet 1A is separated and conveyed from the sheet bundle 1 as follows.

  (1) The sheet bundle 1 stacked in the sheet storage unit 11 is raised by the sheet lifting member driving means 18. At this time, the electrostatic attraction belt 13A adsorption surface and the uppermost sheet 1A are controlled so as to have a set interval d.

  (2) The air blowing unit 14 is operated, and at the same time, the electrostatic attraction belt power supply device 13D is operated to electrostatically adsorb the uppermost sheet 1A to the electrostatic attraction belt 13A. At this time, the air from the air blowing section 14 floats the upstream side of the transport of the uppermost sheet 1A and separates it from the sheet bundle until it can be attracted by the electrostatic attraction belt 13A (FIG. 5B, FIG. 6). (A)). A part of the air blown from the air blower 14 hits the air reflection plate 20, but the air escapes into the gap K between the electrostatic adsorption belts 13A and 13A along the upward air flow between the belts. For this reason, air does not accumulate between the uppermost sheet 1A to be conveyed and the electrostatic adsorption belts 13A and 13A, and the uppermost sheet 1A can be stably adsorbed to the electrostatic adsorption belts 13A and 13A.

  (3) The electrostatic chucking belt driving unit 13E is operated to rotate the electrostatic chucking belts 13A of the electrostatic chucking belt units 131 and 132 to convey the uppermost sheet 1A (FIG. 6B). At this time, even when the uppermost sheet 1A being conveyed covers the gap K between the two electrostatic adsorption belts 13A and 13A, a gap is formed between the uppermost sheet 1A and the second sheet by the protruding member 13F. Then, air flows into this gap and the two sheets are separated (FIG. 6B). Further, the air from the air blowing unit 14 is reflected by the air reflecting plate 20, and the air enters between the uppermost sheet 1A and the lower sheet than the uppermost sheet 1A. Thereby, the uppermost sheet 1A and the lower sheet than the uppermost sheet 1A are well separated.

  (4) The electrostatic attraction belt power supply device 13D and the electrostatic attraction belt driving means 13E are stopped at the same time as the leading edge reaches the next transport roller.

  (5) The control unit controls the sheet elevating member driving means 18 so that the electrostatic attraction belt 13A adsorption surface and the uppermost sheet 1A have the set distance d.

  (6) Thereafter, the operation (2) to the operation (5) are continuously repeated until all the sheets in the sheet storage unit 11 are conveyed or a signal indicating completion of the sheet conveying operation is received.

  As described above, according to the sheet conveying apparatus 10 according to the present embodiment, the left and right sides of the sheet move away from the sheet conveyance center line 23 as the uppermost sheet that has floated advances downstream. For this reason, as a result, the right and left sides of the sheet are widened, and the distortion generated in the floated uppermost sheet can be extended to eliminate deformation such as wrinkles and twists.

<Embodiment 2>
Next, a sheet conveying apparatus according to Embodiment 2 of the sheet conveying apparatus according to the present invention will be described. FIG. 8 shows an arrangement state of the electrostatic attraction belt of the sheet conveying apparatus according to Embodiment 2 of the sheet conveying apparatus according to the present invention, wherein (a) is a schematic diagram showing a first state, and (b) is a schematic diagram showing the first state. The schematic diagram which shows a 2nd state, (c) is a schematic diagram which shows a driving force transmission mechanism.

  In the sheet conveying apparatus according to Embodiment 1 described above, the positions of the driving roller 13B and the driven roller 13C are fixed at the same position in the vertical direction. On the other hand, in the sheet conveying apparatus 30 according to the third embodiment, both the driving roller 13B and the driven roller 13C have the suction position shown in FIG. 11 (1) and the conveying position shown in FIG. 11 (2) in the vertical direction. It was set as the structure made to reciprocate. Other configurations are the same as those of the sheet conveying apparatus according to the first or second embodiment.

<Embodiment 3>
Next, a sheet conveying apparatus according to Embodiment 3 of the sheet conveying apparatus according to the present invention will be described. 9A and 9B show the positions of the driving roller and the driven roller of the sheet conveying apparatus according to the third embodiment of the sheet conveying apparatus according to the present invention. FIG. 9A is a schematic diagram showing the suction position, and FIG. 9B is the conveying position. It is a schematic diagram which shows. In the sheet conveying apparatus 40 according to the third embodiment, the position of the driving roller 13B, the driven roller 13C, and the driven roller 13C is set to the suction position illustrated in FIG. 12A and the conveying position illustrated in FIG. As much as possible, it was configured to reciprocate in the vertical direction. Other configurations are the same as those of the sheet conveying apparatus according to the first or second embodiment.

<Embodiment 4>
Next, a sheet conveying apparatus according to Embodiment 4 of the sheet conveying apparatus according to the present invention will be described. 10A and 10B show a sheet conveying apparatus according to Embodiment 4 of the sheet conveying apparatus according to the present invention. FIGS. 10A and 10B are schematic views showing the operation of the first air blower, and FIG. FIG. 11 is a plan view showing the sheet conveying apparatus, FIG. 12 is a view showing the air blowing state of the sheet conveying apparatus from the Z direction in FIG. (A), (b) is a schematic diagram sequentially showing the conveying operation of the sheet conveying apparatus, FIG. 13 shows the blowing angle from the air blowing section of the sheet conveying apparatus, (a) shows the air blowing state Schematic, (b) is a table showing the air blowing angle.

  The sheet conveying apparatus 50 according to the present embodiment includes a first air blowing unit 14A and a second air blowing unit 14B as the air blowing unit 14, and a sheet levitation preventing plate disposed around the electrostatic adsorption belts 13A and 13A. 29.

  14A of 1st air ventilation parts are just under the clearance gap K between electrostatic adsorption | suction belts 13A and 13A, as shown in locations other than directly under the electrostatic adsorption | suction belt 13A, for example, Fig.12 (a), (b). Is provided. The direction and the position are set so that the air blown from the first air blowing section 14A is directed to the gap K. By blowing air from the first air blowing section 14A, the uppermost sheet 1A and the sheet in the vicinity of the side 1B of the uppermost sheet 1A are levitated and approached or brought into contact with the electrostatic adsorption belt 13A. In addition, by blowing the first air blowing section 14A, air can flow between the uppermost sheet 1A and the lower sheets so that a plurality of sheets can be separated from each other.

  Further, as shown in FIG. 12A, the air passing through the vicinity of the suction surface of the electrostatic suction belt 13A escapes to the gap K between the electrostatic suction belts 13A and 13A before the uppermost sheet 1A is sucked. For this reason, air does not enter between the electrostatic adsorption belts 13A and 13A and the uppermost sheet 1A, and the uppermost sheet 1A can be adsorbed satisfactorily.

  After the uppermost sheet 1A is adsorbed, the gap K is blocked by the uppermost sheet 1A as shown in FIG. 12B, so that air enters between the uppermost sheet 1A and the next sheet of the uppermost sheet 1A. Separation between sheets can be performed satisfactorily. Here, the air from the first air blowing unit 14A is blown to a range other than the area below the electrostatic attraction belt 13A, and the lower portion of the sheet is not levitated. In this case, levitation may be insufficient and adsorption may not be possible.

  Therefore, the sheet conveying apparatus 50 according to the fifth embodiment includes a second air blowing unit 14B that blows air under the electrostatic attraction belt 13A. As shown in FIG. 10 (c), the nozzle that discharges air from the second air blower 14B has an intersection between the extension line on the blower side of the upper part of the nozzle and the suction surface in the vicinity of the end on the downstream side of conveyance of the uppermost sheet 1A. I have to. As a result, the amount of air that floats the uppermost sheet 1A is greater than the air that passes between the electrostatic attraction belt 13A and the uppermost sheet 1A, so that the adsorption can be stabilized.

  Further, the second air blower 14B can be moved in the vertical direction by the air moving means, and moves downward when the sheet type requires a higher levitation force such as a sheet having a large basis weight. By lowering the position of the second air blowing unit 14B, the intersection of the blowing direction and the suction surface moves on the extended line of the upper part of the nozzle, that is, from the leading edge position of the uppermost sheet 1A to the upstream side of the conveyance. Since the sheet levitation force increases and the levitation force of the sheet increases, the levitation of the uppermost sheet is stabilized. The air moving means is configured such that the intersection of the air blowing unit 14 on the extension line in the blowing direction above the nozzle of the second air blowing unit 14B and the suction surface is from the vicinity of the end position on the downstream side of the conveyance of the uppermost sheet. It is possible to move in the vertical direction so as to be upstream from the end position on the downstream side of the transport.

  Here, since the air is blown below the electrostatic adsorption belt 13A, the uppermost sheet 1A is less likely to be flat with respect to the adsorption surface of the electrostatic adsorption belt 13A, and the adsorption portion on the uppermost sheet is biased. There is. When the uppermost sheet 1A is not flat with respect to the attracting surface of the electrostatic attraction belt 13A, the portion of the uppermost sheet 1A that is in contact with the electrostatic attraction belt 13A at the moment when the attraction force is generated on the electrostatic attraction belt 13A It adsorbs and blocks the air flow path that was passing before the adsorption.

  When this occurs, air stays between the electrostatic adsorption belt 13A and the uppermost sheet 1A, and the uppermost sheet 1A and the electrostatic adsorption belt 13A are not sufficiently adsorbed. In order to cope with a sheet type that is particularly easily deformed, it is necessary to sufficiently float the portion of the uppermost sheet 1A below the electrostatic adsorption belt 13A and make the uppermost sheet 1A as flat as possible with respect to the adsorption surface.

  In order to cope with this, the air blowing angles of the first air blowing unit 14A and the second air blowing unit 14B are set as follows. The air blowing angle is obtained by experiments. If it is larger, the reflection becomes larger when air strikes the suction surface, which favors the separation between the uppermost sheet and the next uppermost sheet, and the smaller the air, the lower the air reflection on the suction surface and the easier the air passes through the sheet.

  For this reason, the air and the sheet blown from the second air blowing unit 14B have an air blowing angle α formed by the air blown from the first air blowing unit 14A and the sheet conveyance surface of the electrostatic adsorption belt 13A. It is larger than the air blowing angle β formed by the transport surface. FIG. 12 shows the air blowing angle from the air blowing unit of the sheet conveying apparatus, (a) is a schematic diagram showing the air blowing state, and (b) is a table showing the air blowing angle.

  When the air blowing angle is determined as shown in FIG. 12 (a), the air blowing angle α of the first air blowing unit 14A is larger than 20 °, and the air blowing angle β of the second air blowing unit 14B is set. The range is 0 to 20 ° or less. Thereby, the separation between the uppermost sheet 1A and the next sheet of the uppermost sheet 1A becomes good by the air of the first air blowing section 14A. Further, since the air from the second air blowing unit 14B easily passes in the upstream direction of the uppermost sheet 1A, deformation of the uppermost sheet shape can be reduced.

  The sheet levitation prevention plate 29 is assumed to extend with a certain length in the conveyance direction within the range of the electrostatic attraction belt 13A and in a direction perpendicular to the conveyance direction (the portion indicated by hatching in FIG. 11). The sheet levitation prevention plate 29 is provided to prevent levitation of a large sized sheet that protrudes from the adsorption surface of the electrostatic adsorption belts 13A and 13A. In the case of a large size sheet, the floating amount of the sheet portions other than the suction surfaces of the electrostatic suction belts 13A and 13A due to air increases, and the entire sheet may be deformed and may not be flat with respect to the suction surface. The sheet levitation preventing plate 29 prevents this state. It is preferable that the sheet levitation preventing plate 29 has a height difference between the surface position and the suction surface of 0 to 1 mm.

  By disposing the sheet levitation prevention plate 29, the deformation of the uppermost sheet 1A is reduced, and the adsorption of the uppermost sheet 1A to the electrostatic attraction belt 13A can be stabilized. In addition, it is preferable that a vent hole is formed in the sheet levitation preventing plate 29 as a hole through which air can pass to prevent air from staying under and around the electrostatic attraction belt 13A.

  In the sheet conveying device 50, the air blower 14 is disposed only at a position facing the side 1B. However, one or a plurality of positions may be disposed at positions facing the side 1D and the side 1E.

  FIG. 14 is a table showing combinations of sheet basis weight, interval according to sheet size, and air amount for different types of sheets of non-coated paper typified by fine paper and coated paper typified by coated paper. FIG. In the operation of adsorbing the uppermost sheet 1A to the electrostatic attraction belt 13A in a state where the uppermost sheet 1A is floated by the air blower 14, even when the sheet basis weight, the sheet type, and the sheet size are changed, the most appropriate combination of the distance d and the air amount e By selecting from the table, the sheet conveying operation can be performed satisfactorily.

Note that the table shown in FIG. 14 may have different values or the same values depending on the sheet basis weight, sheet type, and sheet size. For example, if it is a sheet conveying apparatus 10 capable of exhibiting sufficient performance at a boundary between a sheet size of less than A3 and A3 or more,
d1ax = d1bx,
d1ay = d1by,
d1az = d1bz,
e1ax = e1bx,
e1ay = e1by,
e1az = e1bz
Etc.

<Embodiment 5>
Next, a sheet conveying apparatus according to Embodiment 5 of the sheet conveying apparatus according to the present invention will be described. FIG. 15 is a side view showing a sheet conveying apparatus according to a fifth embodiment of the sheet conveying apparatus according to the present invention. 16A and 16B show the operation of the conveyance guide plate of the sheet conveying apparatus. FIG. 16A is a view showing the state in which the uppermost sheet is adsorbed and conveyed as viewed from the right side of FIG. 14, and FIG. FIG. 6 is an enlarged view showing a state in which a part of the air from the section acts as pushed-down air that is reflected by the lower surface of the sheet in the conveyance guide plate and flows downward.

  A sheet conveying apparatus 60 according to the fifth embodiment replaces the air reflecting plate 20 of the configuration of the sheet conveying apparatus according to the first embodiment, and a pair of conveying guide plates 61 arranged at intervals in the vertical direction as shown in FIG. , 61 (hereinafter simply referred to as a conveyance guide plate 61). The conveyance guide plate 61 is a plate-like member provided on both side plate materials with a ventilation portion for air passage.

  As shown in FIG. 16, the case where the air A cannot be separated from the air blowing unit 14 by the air A, and not only the uppermost sheet 1 </ b> A but also the second and subsequent sheets are adsorbed to the electrostatic adsorption belt 13 </ b> A and conveyed in close contact. View. Even in this case, a part of the air A from the air blowing unit 14 provided in the downstream conveyance unit of the electrostatic attraction belt 13A is reflected by the sheet (the lower surface of the uppermost sheet 1A in the illustrated example) and flows downward. Acting as air Ax, only the uppermost sheet 1A is separated and conveyed.

  That is, as shown in FIG. 16B, before the sheet reaches the portion where the ventilation hole of the conveyance guide plate 61 is provided, the pushed-down air Ax passes through the ventilation hole of the conveyance guide plate 61, and the sheet is conveyed to the conveyance guide plate 61. It enters between the plates 61 and reaches to cover some of the ventilation holes. Then, since the sheet is deformed by the air, air enters between the uppermost sheet 1A and a sheet (for example, the second sheet) in close contact with the uppermost sheet 1A as shown in the figure, and the air is pushed down and the air Ax enters. Thereby, the uppermost sheet 1A is separated from two or more sheets that are in close contact with each other, and only the uppermost sheet 1A can be conveyed.

  When the sheet does not reach the conveyance guide plate 61 and the air A is passed through the ventilation hole and the adhered sheet is conveyed, the air A is reflected to the sheet and acts as a push-down air Ax for the adhered sheet. . Thereby, stable sheet conveyance and separation can be performed. Here, the ventilation holes of the conveyance guide plate 61 are not shown. As shown in FIG. 17 (a), the vent hole 61a has a home base type slit shape (width of 3 mm to 5 mm) closed on the downstream side of the sheet conveyance so that the sheet is not caught. .

  Also, as shown in FIG. 17B, by providing protrusions 61b at locations where the conveyance guide plate 61 contacts the sheet, the sheet conveyed in close contact is deformed, and the sheet that is in close contact with the uppermost sheet. The air Ax can be easily pushed in between the two. As a result, stable sheet separation can be performed. The protrusion shape is a semicircular shape (R1 to R5), and does not damage the sheet. In this configuration, the protrusion shape is provided at one central upper portion, but the protrusion shape may be provided not only at the upper portion but also at the lower portion or at a plurality of locations.

<Embodiment 6>
Next, a sheet conveying apparatus according to Embodiment 6 of the sheet conveying apparatus according to the present invention will be described. The sheet conveying apparatus 70 according to the sixth embodiment is configured to be able to move the air reflecting plate 20.

  18A and 18B show a sheet conveying apparatus according to a sixth embodiment of the sheet conveying apparatus according to the present invention, in which FIG. 18A is a side view and FIG. 18B is an arrow view from the A direction in FIG. . FIGS. 19 and 20 show the operation of the sheet conveying apparatus. FIG. 19A is a side view, and FIG. 19B is a view as viewed from the direction A in FIG.

  The main configuration of the sheet conveying apparatus 70 is the same as that of the above-described embodiment. That is, the sheet conveying device 70 includes a sheet storage unit 11 that stores the sheet bundle 1, and an electrostatic adsorption belt device 13 is provided above the sheet storage unit 11. The sheet storage unit 11 includes a sheet elevating member 12 that elevates the sheet bundle and a sheet elevating member driving unit 18 that elevates the sheet elevating member 12. An air blowing unit 14 is provided on the downstream side of the sheet storage unit 11.

  By sending air from the air blower 14 to the sheet bundle 1, the uppermost sheet 1 </ b> A of the sheet bundle 1 and the sheet in the vicinity of the uppermost sheet 1 </ b> A are floated and the sheets are separated. The electrostatic attraction belt device 13 includes an electrostatic attraction belt 13A stretched between a driving roller 13B and a driven roller 13C, and the driving roller 13B can be driven to rotate by an electrostatic attraction belt driving means 13E. The electrostatic attraction belt driving means 13E is a belt made of a sheet-like medium in which a plurality of electrodes 21 are covered with an insulating layer 22 (see FIG. 6). In the plurality of electrodes 21, positive electrodes 21A and negative electrodes 21B are alternately arranged.

  When a voltage is applied to these electrodes 21 from the electrostatic attraction belt power supply device 13D, dielectric polarization occurs, and the attraction surface of the uppermost sheet 1A of the sheet bundle 1 is polarized. (Coulomb force) is generated. The uppermost sheet 1A can be attracted to the electrostatic attraction belt 13A by this electrostatic attraction force. Further, as shown in FIG. 18B, these electrostatic adsorption belt portions are constituted by two electrostatic adsorption belts 13a and 13b while providing a gap B.

  In the gap B, there is an air reflecting plate 20 that can reflect the air from the air blowing section 14. The air reflector 20 is in a state parallel to the uppermost sheet 1A (reflector closed state: FIG. 20) and an oblique state (reflector opened state: FIG. 19) relative to the uppermost sheet 1A by the air reflector driving unit 71. Switching is possible.

  If the reflecting plate is in the closed state, as shown in FIG. 20, the air reflecting plate 20 can reflect the air from the air blowing section 14. On the other hand, as shown in FIG. 19, if the air reflector 20 is in the open state, the air from the air blower 14 is released from the gap B between the electrostatic suction belts 13 a and 13 b of the electrostatic suction belt device 13. it can. A sensor unit 72 capable of detecting the end of the sheet and a roller pair 73 capable of conveying the sheet are disposed on the downstream side of the electrostatic attraction belt device 13. As a result, the sheet conveyed from the electrostatic attraction belt device 13 can be conveyed downstream.

  Next, the operation of the sheet conveying apparatus 70 according to the sixth embodiment will be described. FIG. 21 is a flowchart showing the operation of the sheet conveying apparatus. As shown in FIG. 19, air is sent from the air blowing unit 14 (step S <b> 1), and the uppermost sheet 1 </ b> A of the sheet bundle 1 and the sheet in the vicinity of the uppermost sheet 1 </ b> A are floated to separate the sheets. At that time, the air reflector 20 is in the open state as shown in FIG. Thereby, air can escape from the gap B between the electrostatic adsorption belts 13 a and 13 b of the electrostatic adsorption belt device 13. Thereby, air does not accumulate between the electrostatic attraction belt device 13 and the uppermost sheet 1A, and the uppermost sheet 1A is not pushed down by air. After that, the uppermost sheet 1A floated by air waits for C [sec] in contact with the electrostatic attraction belt 13A (step S2).

  Next, a voltage is applied to the electrostatic attraction belt 13A by the electrostatic attraction belt feeding device 13D. As a result, the uppermost sheet 1A is attracted to the electrostatic attraction belt 13A (step S3). At this time, the air reflecting plate 20 is brought into the reflecting plate closed state by the air reflecting plate driving unit 71 (step S4). By doing in this way, as shown in FIG. 20, the air from the air ventilation part 14 can be reflected with the air reflection board 20, and can be sprayed on the sheet | seat upper surface of the uppermost sheet | seat 1A vicinity (refer FIG. 20). Thereby, the uppermost sheet 1A can be separated from the nearby sheets.

  Further, the electrostatic attraction belt driving means 13E rotates the driving roller 13B (step S5), drives the electrostatic attraction belt 13A, and conveys the attracted uppermost sheet 1A to the downstream roller pair 73. When the leading edge of the uppermost sheet 1A reaches the roller pair 73 (step S6), the electrostatic attraction belt power supply device 13D is stopped and the electrostatic attraction is terminated (step S7). Further, the air reflector driving unit 71 is brought into the reflecting plate open state by the air reflector driving unit 71, and the driving roller 13B is stopped (step S9). At this time, the air from the air blower 14 is reflected by the uppermost sheet 1A, and the sheet in the vicinity of the uppermost sheet 1A is pressed down.

  Next, when the sensor unit 72 detects the trailing edge of the sheet conveyed by the roller pair 73 (step S10), the air from the air blowing unit 14 is not reflected, and the gap B between the electrostatic adsorption belts 13a and 13b. Exit. For this reason, the next sheet of the uppermost sheet 1 </ b> A is floated by air and can be conveyed by the electrostatic attraction belt device 13.

  These operations are performed until the stop command or the sheet bundle 1 runs out. According to the sheet conveying device 70, before the uppermost sheet 1A is adsorbed to the electrostatic adsorption belt 13a, the air from the air blower 14 is sent to the gap B between the electrostatic adsorption belts 13a and 13b. Further, when the uppermost sheet 1A is adsorbed, the air from the air blower 14 is sent to the upper surface of the sheet near the uppermost sheet 1A to stably separate the sheets without disturbing the adsorption of the uppermost sheet 1A. Transport can be performed.

<Embodiment 7>
Next, a sheet conveying apparatus according to a seventh embodiment of the sheet conveying apparatus according to the present invention will be described. 22A and 22B show a sheet conveying apparatus according to a seventh embodiment of the sheet conveying apparatus according to the present invention, in which FIG. 22A is a side view and FIG. 22B is an arrow view from the A direction in FIG. . FIGS. 23 and 24 show the operation of the sheet conveying apparatus, where (a) is a side view and (b) is an arrow view from the A direction in (a).

  In the sheet conveying apparatus 80 according to the seventh embodiment, the air reflector driving unit 71 is arranged in parallel to the uppermost sheet 1A. Further, as shown in FIG. 23, the air reflector driving unit 71 is configured so that the rear end of the air reflector 20 is positioned in the horizontal direction and downstream of the leading edge of the uppermost sheet 1A in the transport direction. Moving. Thereby, the air reflecting plate 20 can be made into a reflecting plate open state (refer FIG. 23), and the air from the air ventilation part 14 can be extracted from the clearance gap B of the electrostatic adsorption belts 13a and 13b.

  As shown in FIG. 24, the air reflector 20 can be moved upstream of the leading edge of the uppermost sheet 1A by the air reflector driving unit 71. With the air reflector 20 in the closed state, the air from the air blower 14 can be reflected by the air reflector 20 and blown onto the upper surface of the sheet near the uppermost sheet 1A.

  The sheet conveying apparatus according to the embodiment of the present invention described above can be used for improving sheet conveying operation in an image forming apparatus such as a digital copying machine, a printer, a facsimile machine, and an offset printing machine. It can also be used by being mounted on other image forming apparatuses or other similar apparatuses.

  The present invention is not limited to the embodiments described above, and many modifications can be made by those having ordinary knowledge in the art within the technical idea of the present invention.

1: Sheet bundle 1A: Top sheet 10: Sheet conveying device 11: Sheet storage unit 12: Sheet elevating member (sheet elevating means)
13: Electrostatic adsorption belt device 13A: Electrostatic adsorption belt 13B: Drive roller 13C: Driven roller 13D: Electrostatic adsorption belt power supply device 13E: Electrostatic adsorption belt drive means 13F: Projection member 13G: Projection amount change means 14: Air Air blower 14A: 1st air blower 14B: 2nd air blower 15A, 15B: Conveyance direction side edge regulation member 18: Sheet raising / lowering member drive means 19: Control means 20: Reflecting plate 21: Electrode 21A: Plus Electrode 21B: Negative electrode 22: Insulating layer 23: Conveying center line 24A: Driving force transmission mechanism 24B: Driving force transmission mechanism 25: Spline joint 25A: Female spline 25B: Male spline 27A, 27B: Constant velocity joint 28: Driving gear 28A : Drive gear 28B: rotation conduction device 29: sheet levitation prevention plate 61, 61: transport guide plate 61a: vent hole 6 b: protrusion 70: a sheet conveying device 71: air reflector driving unit 72: Sensor unit 80: the sheet conveying device 100: a copying machine (image forming apparatus)
110: Automatic document conveying device 120: Document reading unit 130: Paper feeding unit 131, 132: Electrostatic adsorption belt unit 140: Image forming unit 150: Paper feeding cassette 160: Sheet separation paper feeding device 170: Conveying path 180: Conveying roller Pair 190: Transfer roller 200: Fixing device 210: Paper discharge roller pair 220: Paper discharge tray 230: Image forming unit 230Y, 230C, 230M, 230BK: Image forming unit 240: Intermediate transfer belt 250: Exposure device 260: Photoconductor 270 : Charging unit 280: Developing unit 290: Cleaning unit

JP 2007-45630 A

Claims (13)

A sheet storage section for storing the sheet bundle;
Sheet elevating means for elevating the sheet bundle vertically;
A plurality of endless electrostatic attraction belts that are positioned above the sheet bundle and electrostatically adsorb the uppermost sheet, each arranged with a gap therebetween;
By blowing air toward the gap between the electrostatic adsorption belts from below the position of the adsorption surface of the electrostatic adsorption belt at a position near the uppermost sheet of the sheet bundle stored in the sheet storage unit, An air blowing unit for levitating the uppermost sheet and a sheet below the uppermost sheet and separating the uppermost sheet;
A sheet conveying apparatus comprising:   The air blown from the air blower before passing the uppermost sheet to the electrostatic adsorption belt passes through the gap between the electrostatic adsorption belts between the plurality of electrostatic adsorption belts. 2. The sheet according to claim 1, wherein an air reflecting plate that reflects the air from the air blowing unit is disposed at a position that is in a range and that a part of the air from the air blowing unit hits. Conveying device.   3. The driving device according to claim 2, further comprising a driving unit configured to switch the air reflecting plate so that the air sent from the air blowing unit is sent to a sheet upper surface near the uppermost sheet when the uppermost sheet is adsorbed. Sheet conveying device.   A region where the air from the air blower can pass through the gap between the electrostatic adsorption belts in a state where the uppermost sheet is not lifted in the gap between the plurality of electrostatic adsorption belts Further, when the uppermost sheet levitated and floated from the adsorption surface of the electrostatic adsorption belt covers a gap between the electrostatic adsorption belts, the uppermost sheet is deformed, and the uppermost sheet and the uppermost sheet are next to the uppermost sheet. The sheet conveying apparatus according to any one of claims 1 to 3, further comprising at least one protruding member that forms a space in which air enters between the sheet and the sheet.   The sheet conveying apparatus according to claim 4, wherein the protruding member includes a rotating member that rotates as the uppermost sheet moves.   The sheet conveying apparatus according to claim 4, further comprising: a protruding amount changing unit that changes a protruding amount of the protruding member from the adsorption surface of the electrostatic adsorption belt. The air blowing part is
By blowing air toward the space between the electrostatic adsorption belts from below the position of the adsorption surface of the electrostatic adsorption belt at a position near the uppermost sheet of the sheet bundle stored in the sheet storage unit, A first air blower that separates a sheet and a sheet lower than the uppermost sheet;
Air is blown from below the position of the suction surface of the electrostatic suction belt toward the lower portions of the plurality of electrostatic suction belts to float the uppermost sheet to the suction surface of the electrostatic suction belt, and A second air blowing unit for performing sheet floating and separation lower than the uppermost sheet in the sheet and the sheet bundle;
The sheet conveying apparatus according to any one of claims 1 to 6, further comprising:   In the second air blower, the intersection of the suction direction and the extension line in the blowing direction above the nozzle of the second air blower is near the end position of the uppermost sheet on the downstream side of the conveyance of the uppermost sheet. The sheet conveying apparatus according to claim 7, further comprising an air moving unit capable of moving in an up-down direction so as to be upstream from an end position on the downstream side of conveyance.   The angle formed between the air blown from the first air blower and the sheet conveyance surface of the electrostatic adsorption belt is the angle formed between the air blown from the second air blower and the sheet conveyance surface. 9. The sheet conveying apparatus according to claim 7, wherein the sheet conveying apparatus is larger. Around the periphery of the electrostatic adsorption belt is provided with a levitation prevention plate that prevents the uppermost sheet from being blown upward from the adsorption surface to a portion outside the electrostatic adsorption belt,
The sheet conveyance according to any one of claims 1 to 9, wherein the levitation prevention plate has a surface position that is 0 to 1 mm in difference from the height of the adsorption surface of the electrostatic adsorption belt. apparatus.   The sheet conveying apparatus according to claim 10, wherein the levitation preventing plate has a hole for allowing the air blown from the air blower to pass therethrough.   The sheet conveying apparatus according to claim 1, further comprising an air amount changing unit that changes an amount of air blown from the air blowing unit.   An image forming apparatus comprising: the sheet conveying apparatus according to any one of claims 1 to 12; and an image forming unit that performs image forming processing on the sheet conveying apparatus.