JP6051914B2 - Sheet conveying apparatus, sheet feeding apparatus, and image forming apparatus - Google Patents

Description

  The present invention relates to an electrostatic attraction type sheet conveying device and a sheet feeding device, and an image forming apparatus including the sheet conveying device or the sheet feeding device.

  Electrostatic adsorption type sheet conveyance as a sheet conveyance device for conveying sheets (paper, recording paper, transfer paper, plain paper, recording or printing sheets, etc.) used in image forming apparatuses such as copying machines and printers The device is known. For example, Patent Document 1 discloses a sheet feeding device which is a kind of a sheet conveying device using an electrostatic adsorption method.

  The sheet feeding device includes an electrode-embedded electrostatic attraction belt that is wound around a driving roller and a driven roller and moves around. In the electrostatic adsorption belt, electrodes to which voltages of opposite polarity are alternately applied at intervals in the moving direction are arranged in an insulating layer, and the surface is contacted by applying a voltage to the electrodes. Surface polarization is induced in the sheet. Therefore, an electrostatic field is formed between the sheet and the electrode in the electrostatic attraction belt, and the sheet is attracted to the surface of the electrostatic attraction belt by the electrostatic attraction force and conveyed.

  In the sheet feeding device described in Patent Document 1, in order to apply a voltage to the electrode in the above-described electrostatic attraction belt, a lead wire for power feeding is passed through the shaft of the driving roller and along the outer peripheral surface of the driving roller. Connected to the slip ring. On the other hand, a power feeding ring is provided which is connected to an electrode in the electrostatic attraction belt and is exposed on the inner surface of the electrostatic attraction belt to come into contact with the slip ring. A voltage is applied to the positive and negative electrodes in the electrostatic attraction belt from the outside through the lead wire, slip ring, and power feeding ring.

However, when the power feeding portion to the electrode in the electrostatic attraction belt has the above-described structure, the portion where the power feeding ring of the electrostatic attraction belt is formed moves around while always contacting the slip ring on the driving roller side with a small area. It will be. As a result, the contact portion of the electrostatic adsorption belt that contacts the slip ring wears out and deteriorates, so there is a problem that the durability of the electrostatic adsorption belt is reduced. Also, the contact area between the slip ring and the power supply ring is small. For this reason, there is also a problem that a voltage cannot be stably applied to the electrodes in the electrostatic attraction belt.

  The present invention has been made in view of the above points, and in a sheet conveying apparatus equipped with an electrode-embedded electrostatic adsorption belt, the durability of the electrostatic adsorption belt is improved and the electrodes in the electrostatic adsorption belt The purpose is to make it possible to always supply power stably.

A sheet conveying apparatus according to the present invention is configured to hang an electrode-embedded electrostatic adsorption belt having a plurality of electrodes provided in a belt base material made of a flexible strip-shaped insulating material between at least two rollers, A sheet conveying apparatus that adsorbs and conveys a sheet to the surface of the electrostatic attraction belt by electrostatic attraction by moving the electrostatic attraction belt while applying a voltage to the plurality of electrodes. In order to achieve the above object, the present invention is configured as follows.
On the inner peripheral surface of the electrostatic chucking belt, a plurality of power feeding locations where a part of the plurality of electrodes are exposed along the moving direction of the electrostatic chucking belt are formed. At least a pair of power feeding units is provided.
Each of the power supply portions has a conductive power supply belt that is endlessly stretched between a plurality of electrically conductive rotating bodies, and the power supply belt is the power supply location of the electrostatic attraction belt. The electrostatic attraction belt is configured to rotate along with the circumferential movement of the electrostatic attraction belt while contacting the inner peripheral surface including the portion where the is formed.
Then, by applying a voltage to each of the power feeding units, a voltage is applied to the plurality of electrodes of the electrostatic attraction belt through the upper power feeding belt, and the electrostatic attraction force is applied to the outer peripheral surface of the electrostatic attraction belt. It was made to occur.

  The sheet conveying device according to the present invention improves the durability of the electrostatic chucking belt of the electrode embedded type that transports the sheet by electrostatic chucking force, and can always stably supply power to the electrodes in the electrostatic chucking belt. it can.

It is a side view which shows one Embodiment of the sheet conveying apparatus by this invention except the support frame of the rotary body. It is sectional drawing containing the support frame of the rotary body which follows the YY line of FIG. FIG. 2 is a plan view of only the power feeding unit 10 of the sheet conveying apparatus illustrated in FIG. 1 as viewed from above. It is a typical expanded sectional view which shows the internal structure of the electrostatic attraction belt 4 shown in FIG. It is explanatory drawing which shows the state at the time of charging of the electrostatic attraction belt shown in FIG. 4 with the sheet | seat attracted | sucked. It is sectional drawing similar to FIG. 2 which shows other embodiment of the sheet conveying apparatus by this invention.

It is the top view which similarly looked at the electric power feeding part 10 of the sheet conveying apparatus from the upper direction. It is a side view showing one embodiment at the time of using the sheet conveyance device by this invention as a sheet feeding device. It is a side view which shows a mode that the electrostatic attraction | suction belt of the sheet | seat delivery apparatus shown in FIG. 8 adsorb | sucks a sheet | seat. FIG. 3 is a view similarly showing the main part of the sheet feeding device in the same cross section as FIG. 2. 1 is a schematic diagram illustrating a configuration of a main part of an embodiment of an electrophotographic color image forming apparatus including a sheet conveying device according to the present invention.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.
[Embodiment of Sheet Conveying Device]
First, an embodiment of a sheet conveying apparatus according to the present invention will be described with reference to FIGS.
FIG. 1 is a side view showing the sheet conveying apparatus excluding the support frame of the rotating body, and FIG. 2 is a cross-sectional view including the support frame of the rotating body along YY in FIG. FIG. 3 is a plan view of only the power feeding unit as viewed from above. The overall configuration of the sheet conveying apparatus will be described with reference to these drawings.

As shown in FIG. 1, the sheet conveying apparatus 1 includes a driving roller 2 and a driven roller 3 that are arranged in parallel to each other at an interval, and an electrostatic attraction belt 4 that is stretched therebetween. The driving roller 2 is transmitted via a transmission mechanism 5a indicated by a straight line in which the rotational force of the motor 5 is simplified, and is rotationally driven in the direction indicated by the arrow B, and moves around the electrostatic adsorption belt 4 in the direction indicated by the arrow A. (Hereinafter referred to as “rotation”). The driven roller 3 is driven to rotate in the direction indicated by the arrow by the rotation of the electrostatic attraction belt 4.
The transmission mechanism 5a includes a speed reduction mechanism such as a gear speed reduction mechanism or a belt speed reduction mechanism. The motor 5 is driven and controlled by a drive control circuit (not shown).
In this embodiment, the electrostatic adsorption belt 4 is stretched between two rollers, but may be stretched by three or more rollers.

Further, as shown in FIGS. 2 and 3, the sheet conveying device 1 is respectively paired at intervals in the width direction orthogonal to the traveling direction (the direction indicated by arrow A) by the rotation of the electrostatic attraction belt 4. A power feeding unit 10 and a rotation assisting unit 15 are provided to face each other so as to sandwich the electrostatic attraction belt 4.
In FIG. 1, since the sheet is attracted and conveyed to the lower outer peripheral surface of the electrostatic adsorption belt 4, the left side is the upstream side in the sheet conveying direction. In FIG. 3, the electrostatic attraction belt 4 is indicated by a virtual line.

  Each of the pair of power supply units 10 is provided on the inner peripheral surface side of the electrostatic attraction belt 4, and at least one of the power supply units 10 is endlessly spanned between a plurality of conductive (two in the illustrated example) rotating bodies 11. A conductive power supply belt 12. In this example, each rotating body 11 includes a conductive pulley 11a and a conductive rotating shaft 11b, and each rotating shaft 11b is rotatably held by a support member 13 formed of a common conductive material. ing.

If each power feeding section 10 is configured in this way, when a voltage is applied to the support member 13, the voltage is applied to each pulley 11a through the plurality of rotating shafts 11b, and is uniformly applied from each pulley 11a to the power feeding belt 12. The In addition, assembly of the power feeding unit 10 is facilitated.
However, if at least one rotating body 11 is conductive, a voltage can be applied to the power feeding belt 12 by applying a voltage to the rotating body. In that case, part or all of the support member 13 may be formed of an insulating material.
Each power supply unit 10 is arranged such that each power supply belt 12 is in contact with the inner peripheral surface along the moving direction of the electrostatic adsorption belt 4, and the electrostatic adsorption belt 4 is rotated in the direction of arrow A. Accordingly, each power supply belt 12 rotates in the same direction.

The electrostatic adsorption belt 4 is an electrode-embedded electrostatic adsorption belt that adsorbs a sheet by electrostatic attraction force. As shown in FIG. 4, the electrostatic adsorption belt 4 includes a belt base material 16 made of a strip-shaped insulating material, and a pair of a positive electrode 17 and a negative electrode 18 which are a plurality of electrodes made of a conductive material. Embedded.
The electrodes 17 and 18 are each formed in a comb-like pattern extending in the width direction of the electrostatic attraction belt 4 (in the direction perpendicular to the paper surface in FIG. 4) and alternately facing each other at a slight interval. . The electrode 17 and the electrode 18 are covered with a belt base material 16 made of a flexible band-shaped insulating material (insulating sheet) made of rubber, resin, or the like to form an endless electrostatic adsorption belt 4 as a whole. Yes.

Each pair of power supply units 10 is a power supply unit that supplies power to the positive electrode 17 and the negative electrode 18 embedded in the electrostatic attraction belt 4, and one power supply unit 10 is assigned to the one to which a positive voltage is applied. The other power supply unit 10 is assigned to the one to which a negative voltage is applied.
1 applies a positive voltage to the rotating body 11 of one power supply unit 10 and a negative voltage to the rotating body 11 of the other power supply unit 10 through the power supply line 6a.

On the other hand, on the inner peripheral surface of the belt base material 16 of the electrostatic attraction belt 4, a feeding point (not shown) in which a part of one electrode 17 is exposed over the entire circumference along one side edge portion. A power feeding location is formed by exposing a part of the other electrode 18 along the other side edge portion over the entire circumference.
The power supply belt 12 of the power supply unit 10 that supplies a positive voltage comes into contact with the power supply location where a part of the one electrode 17 is exposed, and a positive voltage is applied to the electrode 17 from the inner peripheral surface of the electrostatic adsorption belt 4. Can be applied.

The power supply belt 12 of the power supply unit 10 that supplies a negative voltage comes into contact with the power supply location where a part of the other electrode 18 is exposed, and a negative voltage is applied to the electrode 18 from the inner peripheral surface of the electrostatic adsorption belt 4. Can be applied.
That is, on the inner peripheral surface of the electrostatic attraction belt 4, a plurality of power feeding locations where a part of the plurality of electrodes 17 and 18 are respectively exposed along the moving direction of the electrostatic attraction belt 4 are formed. At least a pair of power supply units 10 is provided for each location.

  On the other hand, the pair of rotation assisting portions 15 are provided on the outer peripheral surface side of the electrostatic attraction belt 4. Each of the rotation assisting portions 15 includes a rotating body 15a that is a rotation assisting member, a compression spring 15b that is a pressing member for pressing the rotating body 15a against the electrostatic attraction belt 4, and a holder 15c that houses them. Has been. The holder 15c is attached to a fixing member (not shown) to which the sheet conveying apparatus 1 is attached.

In FIG. 1 and FIG. 2, the structure of the rotation assistance part 15 is simplified and shown. Actually, for example, the compression spring 15b is mounted between the holder 15c and the member that supports the rotating shaft of the rotating body 15a, and the rotating body 15a is directed to the electrostatic adsorption belt 4 by its restoring force (elastic force). Configured to be pressed.
Accordingly, each rotation assisting portion 15 presses the rotating body 15a, which is a rotation assisting member, with the restoring force of the compression spring 15b so as to sandwich the electrostatic attraction belt 4 between each power feeding portion 10.

Then, when the driving roller 2 is rotated in the direction indicated by the arrow B by the driving means including the motor 5 shown in FIG. 1 and the electrostatic chuck belt 4 is rotated in the direction indicated by the arrow A, each of the rollers comes into contact with the inner peripheral surface. The power feeding belts 12 of the power feeding unit 10 are rotated in the same direction.
At that time, the power supply belt 12 of each power supply unit 10 rotates while contacting the inner peripheral surface including the portion where each power supply location of the electrostatic adsorption belt 4 is formed. As a result, a positive voltage and a negative voltage supplied from the power supply unit 6 to each power supply belt 12 through the power supply line 6a and each rotating body 11 are applied to the electrode 17 and the electrode 18, respectively.

Next, the principle of electrostatic adsorption of the sheet by the electrostatic adsorption belt 4 will be described with reference to FIG.
FIG. 5 is an explanatory view showing a state of charging of the electrostatic attraction belt shown in FIG. 4 together with an adsorbed sheet.
By applying positive and negative high voltages such as +1 kV and −1 kV to the positive electrode 17 and the negative electrode 18 of the electrostatic adsorption belt 4 described above, the electrodes 17 and 18 are As shown in FIG. 5, it is charged to positive charge and negative charge.

  When an insulating sheet S such as a recording sheet comes into contact with the surface of the belt base 16 of the electrostatic attraction belt 4, electrostatic polarization is induced on the surface of the sheet S. Then, at the position of the sheet S facing the plus electrode 17 and the minus electrode 18, a charge having a polarity opposite to that of the facing electrode 17 or 18 is induced. An electrostatic field is generated between the electrodes 17 and 18 and the sheet S due to the charge having the opposite polarity, and an attracting force due to an electrostatic attractive force is generated as indicated by broken line arrows.

That is, an electrostatic attraction force is generated on the outer peripheral surface of the electrostatic attraction belt 4, and the sheet S is adsorbed by the electrostatic attraction force.
In addition, since the electrodes 17 and 18 charged with positive charges and negative charges respectively are alternately arranged in the running direction (arrow A direction) of the electrostatic attraction belt 4, the positive charge is also applied to the surface of the sheet S in the belt running direction. And negative charge appear alternately.

Thereby, a repulsive force is also generated between the electrostatic attraction belt 4 and the sheet S due to the charges having the same polarity, but the component force of the repulsive force in the belt traveling direction is alternately reversed. For this reason, once the sheet S is electrostatically attracted to the surface of the electrostatic attraction belt 4, it does not deviate from the attracted position.
Thus, if the sheet S is attracted to the surface of the electrostatic attraction belt 4 and the electrostatic attraction belt 4 is moved in the direction of arrow A in FIG. It can be accurately transported in the direction of arrow A without causing a shift.

According to the sheet conveying apparatus 1 of this embodiment, the power supply belt 12 of each power supply unit 10 rotates along with the rotation of the electrostatic suction belt 4 when the electrostatic suction belt 4 rotates. Therefore, the load of the pressing force on the power feeding location of the electrostatic attraction belt 4 can be reduced, power can be supplied without damaging the power feeding location, and the durability of the electrostatic attraction belt 4 is improved.
In addition, since the power supply belt 12 of each power supply unit 10 has a wide contact surface with the electrostatic adsorption belt 4, power can be stably supplied to the electrodes 17 and 18 of the electrostatic adsorption belt 4.

  Further, the power supply belt 12 of the power supply unit 10 contacts the inner peripheral surface of the electrostatic adsorption belt 4, and the rotating body 15 a that is a rotation auxiliary member of the rotation auxiliary unit 15 contacts the outer peripheral surface. Hold it. Therefore, the contact property between each power supply unit 10 and each power supply location during rotation of the electrostatic attraction belt 4 is improved. For this reason, even when the electrostatic attraction belt 4 is slightly bent, power can be stably supplied.

The power supply belt 12 may be formed of a conductive member, for example, a material such as urethane rubber or polyisoprene rubber (PI) having a greatly reduced electric resistance. However, the power supply belt 12 is not limited to this as long as it is conductive and durable.
By supporting the plurality of rotating bodies 11 in each power supply unit 10 with a common support member 13, the tension of the power supply belt 12 can be kept constant. Thereby, since the contact with the electrostatic attraction belt 4 is stabilized, the adsorption stability of the electrostatic attraction belt 4 can be improved.

  Further, the rotating body 15a of each rotation assisting portion 15 is pressed against the electrostatic attraction belt 4 by the restoring force of the compression spring 15b. Thereby, even if the electrostatic attraction belt 4 rotates at high speed and vibration (flapping) occurs, power can be stably supplied.

FIGS. 2 and 3 show examples in which the support members 13 of the pair of power supply units 10 and 10 are separated. However, as shown in FIGS. 6 and 7, the rotating shafts 11 b of the two sets of rotating bodies 11 that span the feeding belts 12 of the pair of feeding units 10 and 10 are all supported by a common support member 19. You may comprise as follows. In this case, the common support member 19 needs to be formed of an insulating material or insulated between one power supply unit 10 and the other power supply unit 10 provided in a pair.
In this way, since the pair of power feeding units 10 and 10 can be assembled to the electrostatic attraction belt 4 at a time, the assembling property of the power feeding unit 10 in the sheet conveying apparatus 1 is improved.

  Furthermore, since the height deviation of the belt surface of the power feeding belt 12 in each power feeding unit 10 can be suppressed with respect to the outer circumferential surface of the electrostatic chucking belt 4, each power feeding belt 12 to the outer circumferential surface of the electrostatic chucking belt 4 can be suppressed. The height deviation can be reduced. Therefore, the rotational load of the electrostatic attraction belt 4 can be reduced and the durability can be improved.

  Such a sheet conveying device is a printer, a copying machine, a facsimile machine, a digital multifunction machine having a plurality of functions thereof, or an image forming apparatus such as an offset printing machine, a sheet conveying apparatus or a sheet feeding apparatus of a printing apparatus. Can be used as a device. Furthermore, the present invention can also be applied to various devices that handle other sheets (devices that sort, count, convey, and process various types of paper and banknotes). The electrostatic adsorption belt may be stretched by three or more rollers. Further, the power feeding belt of each power feeding unit may be stretched by three or more rotating bodies.

  Each roller that stretches the electrostatic attraction belt may be formed of an insulating material or at least the outer periphery so that the plurality of power feeding locations may not be conducted even if the rollers may contact the power feeding locations of the electrostatic attraction belt. The part is preferably covered with an insulating material. The number of power feeding locations provided on the electrostatic attraction belt is not limited to two, and the number of power feeding portions and rotation assisting portions can be further increased according to the number of power feeding locations.

  The voltage applied to each electrode in the electrostatic attraction belt is not limited to a voltage having a different polarity, and may be a positive or negative voltage with respect to the ground potential (0 V), or a voltage having the same polarity and a different potential. That is, any voltage may be used as long as it generates an electric field that allows dielectric polarization to be generated in an insulating sheet such as paper that contacts the electrostatic attraction belt so that the sheet can be adsorbed by electrostatic attraction.

[Embodiment of sheet feeding device]
Next, an embodiment of a sheet feeding unit using the sheet conveying apparatus according to the present invention as a sheet feeding apparatus will be described with reference to FIGS. In these drawings, portions corresponding to those in FIGS. 1 to 7 are denoted by the same reference numerals. 8 and 9, the left side is the upstream side in the sheet conveying direction.

  The sheet feeding device 7 shown in FIGS. 8 to 10 is provided in a paper feeding section of various image forming apparatuses such as a printer, a copying machine, a facsimile machine, a digital multifunction machine having a plurality of functions thereof, or an offset printing machine. An example is shown. The sheet feeding device 7 includes an electrostatic attraction belt 4 that is stretched between the driving roller 2 and the driven roller 3, similarly to the sheet conveying device 1 described with reference to FIGS. 1 to 7.

  In addition, the sheet feeding device 7 includes a pair of power feeding units 10 and a rotation assisting unit 15 that are provided so as to face each other so as to sandwich a belt feeding point between the inner peripheral surface side and the outer peripheral surface side of the electrostatic attraction belt 4. A motor 5 for rotating the electrostatic attraction belt 4 and a power source 6 are also provided. Since the configuration and function of each part are the same as those of the sheet conveying apparatus 1 described above, description thereof will be omitted.

  A sheet storage unit 20 is provided below the sheet feeding device 7. In the sheet storage unit 20, a sheet stacking plate 21 that is a sheet lifting member that can be moved up and down, and an upstream end regulation in the transport direction for aligning the upstream end of the sheet S in the transport direction in the sheet storage unit 20. A member 22 is provided. Further, as shown in FIG. 10, the sheet storage unit 20 includes conveyance direction side end regulating members 23 and 24 for aligning both side ends of the sheets S in the conveyance direction.

Further, the sheet feeding device 7 includes a mechanism unit that raises and lowers the sheet stacking plate 21 and an elevating drive unit that includes a motor 25 that is a power source for driving the mechanism unit.
The raising / lowering driving means drives and controls the motor 25 by a control unit (not shown) of the image forming apparatus provided with the sheet feeding device 7 to raise and lower the sheet stacking plate 21. Then, the sheet stacking plate 21 is raised so that the uppermost sheet of the sheet S such as recording paper stacked on the sheet stacking plate 21 is in contact with the lower surface of the electrostatic attraction belt 4 of the sheet feeding device 7.

As a result, the electrostatic adsorption belt 4 of the sheet feeding device 7 electrostatically adsorbs the uppermost sheet to the outer peripheral surface. Then, by rotating the driving roller 2 in the arrow B direction and rotating the electrostatic chuck belt 4 in the arrow A direction, the uppermost sheet can be fed out in the arrow C direction.
In this way, the sheet feeding device 7 sucks and feeds the sheets stacked in the sheet storage unit 20 one by one. A separation claw may be provided at a position where the sheet is separated from the surface of the electrostatic adsorption belt 4.

Instead of the sheet storage unit 20, a paper feed cassette, a paper feed tray, or a manual paper feed tray may be provided. By providing such a sheet feeding device 7, the sheet storage unit 20, and a paper feeding cassette in the paper feeding unit of the image forming apparatus and the printing apparatus, the sheets for image formation (printing) are surely fed out one by one. be able to.
In various apparatuses that handle other sheets, the necessary sheets can be reliably fed out one by one.

[Embodiment of electrophotographic color image forming apparatus]
Next, an embodiment of an electrophotographic color image forming apparatus provided with a sheet conveying apparatus according to the present invention will be described with reference to FIG.
FIG. 11 is a schematic diagram showing the configuration of the main part of the electrophotographic color image forming apparatus, and parts corresponding to those in FIGS. 1 to 7 are given the same reference numerals.
This image forming apparatus is a tandem type direct image transfer type color image forming apparatus in which image forming portions for respective colors are arranged along a transfer conveyance belt.

  The image forming apparatus provided with the sheet conveying device according to the present invention may be any of a printer, a copying machine, a facsimile machine, a digital multifunction machine having a plurality of functions thereof, an offset printing machine, etc. The common parts are shown in FIG. In this image forming apparatus, the sheet conveying apparatus according to the present invention is used as the transfer conveying apparatus 30.

  Similar to the sheet conveying apparatus 1 described with reference to FIGS. 1 to 3, the transfer conveying apparatus 30 includes an electrostatic adsorption belt 4 stretched between the driving roller 2 and the driven roller 3, a pair of power feeding units 10, and the like. It is comprised by the rotation assistance part 15 grade | etc.,. Since the configuration and function of each part are the same as those of the sheet conveying apparatus 1 described above, description thereof is omitted.

In this image forming apparatus, each power feeding unit 10 and each rotation assisting unit 15 are provided to face the inner peripheral surface side and the outer peripheral surface side of the lower side portion of the electrostatic attraction belt 4. The electrostatic adsorption belt 4 functions as a transfer conveyance belt.
As shown in FIG. 11, on the upper portion of the transfer conveyance device 30, image forming units that form images of different colors (yellow: Y, magenta: M, cyan: C, black: K) are provided with sheets S. Arranged in a line along the electrostatic attraction belt 4 transported in the direction of arrow F. Note that the sheet S used in the image forming apparatus is a recording sheet generally referred to as “transfer sheet”.

  A sheet feeding tray 31 in which a large number of sheets S are stored is provided below the electrostatic attraction belt 4. The uppermost sheet S among the sheets S stored in the sheet feeding tray 31 is fed in a direction indicated by an arrow D by a feeding roller (not shown) during image formation. The sheet S is electrostatically attracted to the surface of the electrostatic attraction belt 4 to which a voltage is applied to each electrode by each power supply unit 10 of the transfer conveyance device 30.

  The sheet S adsorbed on the electrostatic attraction belt 4 is conveyed to an image forming unit indicated by Y, where yellow image formation is performed. Each image forming unit is disposed on the lower side of the photosensitive drum 32, the charger 33, the developing unit 34, the photosensitive cleaner 35, and the like disposed around the photosensitive drum 32, and the electrostatic adsorption belt 4. The transfer unit 36 and an exposure unit 37 common to the four image forming units. However, each developing device 34 is a developing device that develops with yellow, magenta, cyan, and black toners in order from the right side in FIG.

  The exposure device 37 irradiates each photosensitive drum 32 of the image forming unit for each color with laser beams LY, LM, LC, and LK corresponding to the yellow, magenta, cyan, and black images, respectively. . In the image forming unit indicated by Y, the surface of the photosensitive drum 32 is uniformly charged by the charger 33 and then exposed by the exposure device 37 with the laser beam LY corresponding to the yellow image, and the yellow portion image An electrostatic latent image is formed.

  The electrostatic latent image formed on the photosensitive drum 32 is developed with yellow toner by the developing unit 34, and a yellow toner image is formed on the photosensitive drum 32. The yellow toner image is transferred by the transfer unit 36 at a position (transfer position) where the photosensitive drum 32 and the sheet S on the electrostatic attraction belt 4 are in contact with each other, and a yellow image is formed on the sheet S. After the transfer of the toner image, the photosensitive drum 32 is cleaned with unnecessary toner remaining on the drum surface by the photosensitive cleaner 35 to prepare for the next image formation.

  As described above, the sheet S on which the yellow image is transferred by the image forming unit indicated by Y is conveyed to the image forming unit indicated by M by the electrostatic attraction belt 4. Here, in the same manner as described above, the electrostatic latent image formed by exposing the photosensitive drum 32 with the laser beam LM corresponding to the magenta image is developed by the developing unit 34 with the magenta toner and formed. A magenta toner image is transferred onto the sheet S in an overlapping manner.

  The sheet S is further conveyed sequentially to an image forming portion indicated by C and an image forming portion indicated by K. In the same manner as described above, the formed toner images of cyan and black are sequentially transferred and transferred in full color. Form an image. Then, the sheet S on which the full color image is formed by passing through the image forming portion indicated by K is peeled off from the electrostatic adsorption belt 4 and the color image on the sheet S is fixed by the fixing device 38, and then the arrow E The paper is conveyed in the direction and discharged to a paper discharge tray (not shown).

Further, a cleaning unit 39 is provided for the electrostatic attraction belt 4 after the sheet S has been peeled off, whereby the residual toner is removed. According to this image forming apparatus, the toner images of the respective colors created by the image forming units for Y, M, C, and K are sequentially superimposed and transferred while the sheet S as transfer paper is conveyed by the transfer conveying device 30. I will do it.
At that time, the sheet S is accurately conveyed without being lifted or slipped from the surface of the electrostatic adsorption belt 4. Therefore, a high-quality image can be obtained without causing color misregistration. The sheet feeding unit of the image forming apparatus may be provided with the sheet feeding device 7 described with reference to FIGS. 8 to 10 so that the sheets S are sequentially fed from the sheet feeding tray 31 and fed.

Furthermore, the sheet conveying apparatus according to the present invention is a sheet for an ink jet type image forming apparatus in which an image is formed by ejecting ink droplets of each color by an image forming unit comprising recording heads of each color of yellow, cyan, magenta, and black. The present invention can also be applied to a transport device.
The sheet conveying apparatus in that case is also configured by an electrostatic adsorption belt stretched between a driving roller and a driven roller, each power feeding unit, a rotation auxiliary unit, and the like, similarly to the sheet conveying apparatus 1 described with reference to FIGS. Is done.

In the inkjet image forming apparatus, an image is formed on the sheet by the ink ejected from the recording head while electrostatically attracting the sheet to the surface of the electrostatic attracting belt and transporting the image forming unit.
Note that the sheet feeding unit of these image forming apparatuses may be provided with the sheet feeding device 7 described with reference to FIGS. 8 to 10 so that the sheets are sequentially fed from the sheet feeding tray and fed.
The sheet conveying apparatus according to the present invention can also be used as a relay conveying apparatus in the sheet conveying path in the various image forming apparatuses as described above.

  The sheet conveying device and the sheet feeding device according to the present invention can be mounted on various image forming apparatuses such as a copying machine, a printer, a facsimile machine, and an offset printing machine. Furthermore, the present invention can be used for apparatuses that handle various sheets including printed matter and banknotes, for example, various apparatuses that perform sorting, counting, conveyance, coating, and other processes. In addition, it is possible to improve the sheet conveying operation during printing and image reading in each of these apparatuses.

  Further, the above-described embodiment is an example, and various modifications, additions and omissions can be made within the scope described in the claims. For example, the plus and minus electrodes may be formed into two comb-like patterns, or an electrostatic attraction force due to dielectric polarization may be generated, so that various patterns can be changed. The power feeding unit and the rotation auxiliary unit can also be increased or decreased according to the number of electrodes. Furthermore, each embodiment can be implemented in appropriate combination within a consistent range.

1: Sheet conveying device 2: Driving roller 3: Driven roller 4: Electrostatic adsorption belt
5: Motor (for driving the electroadsorption belt) 6: Power supply unit 7: Sheet feeding device 10: Power feeding unit 11: Rotating body 11a: Pulley 11b: Rotating shaft 12: Power feeding belt 13, 19: Support member 15: Rotation auxiliary unit 15a : Rotating body (rotation assisting member) 15b: Compression spring 15c: Holder 16: Belt base material 17, 18: Electrode 20: Sheet storage part
21: Sheet stacking plate 22: Conveying direction upstream end regulating member 23, 24: Conveying direction side end regulating member 25: Lifting drive motor 30: Transfer conveying device 31: Paper feed tray 32: Photosensitive drum 33: Charging Device 34: developing device 35: photoconductor cleaner 36: transfer device 37: exposure device 38: fixing device 39: cleaning unit S: sheet

JP 2010-126317 A

Claims (8)

An electrode-embedded electrostatic adsorption belt with a plurality of electrodes in a belt base material made of a strip-shaped insulating material having flexibility is stretched between at least two rollers, and a voltage is applied to the plurality of electrodes. A sheet conveying device that adsorbs and conveys a sheet to the surface of the electrostatic adsorption belt by electrostatic attraction by moving the electrostatic adsorption belt around,
On the inner peripheral surface of the electrostatic adsorption belt, a plurality of power feeding locations are formed in which a part of the plurality of electrodes are exposed along the moving direction of the electrostatic adsorption belt,
For the plurality of power feeding locations, at least a pair of power feeding portions are provided,
Each of the power supply portions has a conductive power supply belt that is endlessly stretched between a plurality of electrically conductive rotating bodies, and the power supply belt is the power supply location of the electrostatic attraction belt. Is configured to rotate with the circumferential movement of the electrostatic attraction belt while contacting the inner peripheral surface including the portion formed with
When a voltage is applied to each of the power feeding units, a voltage is applied to the plurality of electrodes of the electrostatic attraction belt through the power feeding belt, and the electrostatic attraction force is generated on the outer peripheral surface of the electrostatic attraction belt. A sheet conveying apparatus characterized by the above. In the sheet conveying apparatus according to claim 1,
A rotation assisting member is provided at a position facing each of the power feeding units via the electrostatic attraction belt, and the rotation assisting member is pressed toward the electrostatic attraction belt by a pressing member, and the rotation assisting member and the power feeding are pressed. A sheet conveying apparatus characterized in that the electrostatic attraction belt is sandwiched by a belt. In the sheet conveying apparatus according to claim 1 or 2,
The power feeding units are provided in pairs with a gap in the width direction orthogonal to the moving direction of the electrostatic attraction belt, and the plurality of rotating bodies that span the power feeding belts of the power feeding units are a common support member It is supported by the sheet conveying apparatus characterized by the above-mentioned.   Each of the plurality of rotating bodies that span the power supply belts of the power supply units includes a conductive rotating shaft and a conductive pulley, and a common support member is formed of a conductive material, and the plurality of rotating bodies The sheet conveying apparatus according to claim 3, wherein each of the rotating shafts is rotatably supported. In the sheet conveying apparatus according to claim 1 or 2,
The power feeding units are provided in pairs at intervals in the width direction orthogonal to the moving direction of the electrostatic attraction belt, and at least two sets of the rotating bodies that respectively span the power feeding belts of the power feeding units are provided. A sheet conveying apparatus, wherein the sheet conveying apparatus is supported by a common supporting member, and the common supporting member is formed of an insulating material or insulated between power supply portions provided in the pair.   6. A sheet feeding device, wherein the sheet conveying device according to claim 1 is provided so as to suck and feed stacked sheets one by one by the electrostatic adsorption belt.   An image forming apparatus comprising the sheet feeding device according to claim 6 in a sheet feeding unit.   An image forming apparatus comprising the sheet conveying apparatus according to claim 1, wherein the sheet conveying apparatus conveys a sheet for forming an image in an image forming unit. .

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