JP2011042428A - Sheet material separating-feeding device and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly reliable sheet material separating-feeding device and an image forming device surely separating-feeding a sheet material one by one from a stacked sheet bundle, while restraining influence of an environmental variation and a variation with time, even in various sheet material kinds. <P>SOLUTION: A paper feeder 5 has a sheet material stacking part 15 for stacking a sheet bundle 6 and a separation part 7 having a belt 19 composed of a dielectric, separating a sheet material 6a of the uppermost part among the stacked sheet bundle 6 by attraction force by a nonuniform electric field formed in the belt 19 and carrying the separated sheet material 6a to a carrying passage 50 by being attracted to the belt 19 by the attraction force, and can contact and separate the belt 19 and the stacked sheet material 6a. The separation part 7 has a holding roller 72 capable of contacting-separating to the sheet material 6a attracted to the belt 19. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a sheet material separating and feeding apparatus and an image forming apparatus, and more particularly to a sheet material separating and feeding apparatus that uses static electricity to adsorb and separate a sheet material on an endless belt, and the sheet material separating and feeding device. The present invention relates to an image forming apparatus including an electrophotographic copying machine, a facsimile apparatus, a printer apparatus, and the like provided with a feeding apparatus.

  In general, as a sheet material separating and feeding method for image forming apparatuses such as electrophotographic copying machines, facsimiles, and printers, friction feeding by a pickup member formed as a roller or belt made of a material having a high friction coefficient such as rubber. The method is widely adopted.

  The sheet material separating and feeding apparatus adopting this friction feeding method can be simplified in structure, but in order to obtain a large frictional force, a pickup member made of rubber or the like is pressed against the sheet surface by a spring or the like. It is necessary to let Here, a material such as rubber having a high friction coefficient lacks stability in sheet feeding performance because the friction coefficient of the surface changes due to deterioration due to pressure contact with the sheet surface, deterioration with time, and environmental change.

  In particular, printers are using not only plain paper but also various types of recording paper such as coated paper and label paper due to the diversification of users. Both the number and type of printing paper will continue to increase. is there. Some of these special-purpose recording papers have extremely small friction coefficients. In addition, when the frictional separation is performed, there is a problem that the recording paper layer is peeled off due to the pressure contact of the rotating roller. For this reason, it is often difficult to separate the sheet material in the friction feeding method.

  On the other hand, in addition to the friction feeding method described above, as a sheet material separation and feeding method for an image forming apparatus, an electrostatic adsorption separation method for attracting and separating a sheet material using static electricity is known. A sheet material separating and feeding apparatus adopting this electrostatic adsorption separation system is made of a derivative, and is arranged so as to face the upper surface of the stacked sheet bundle and to circulate in the sheet feeding direction. A charging member that forms a charge pattern by applying an alternating voltage to the surface and a charge removal member that removes the charge pattern of the endless belt are provided.

  As a result, the sheet material separating and feeding apparatus described above forms a charge pattern on the surface of the endless belt, and generates an adsorption force by an electric field generated by the charged charge, so that the uppermost sheet from the stacked sheet bundle can be obtained. The material can be adsorbed and separated and conveyed to the sheet material conveyance path. However, in the sheet material separating and feeding apparatus adopting the electrostatic adsorption separation method, it may not be possible to generate the adsorption force required for separation and feeding due to fluctuations in the electrical resistance value of the sheet material, Until a certain time elapses after the contact between the belt and the sheet material, not only the uppermost sheet material but also a plurality of stacked sheet materials may exert an attractive force due to an electric field.

  As described above, when the suction force necessary for separating and feeding the sheet material cannot be obtained, the sheet material is not fed. Further, when the endless belt is circulated in the sheet feeding direction in a state where the adsorbing force is applied to the plurality of sheet materials, double feeding of the sheet materials occurs. For this reason, there is a problem that the sheet material cannot be reliably separated and fed.

  For the above problem, an adsorption separation unit that holds and separates the uppermost sheet material, a drive control unit that moves the adsorption separation unit, a sheet conveyance unit that conveys the separated uppermost sheet material, A separation auxiliary unit that assists the separation operation of the uppermost sheet material by the adsorption separation unit, and the drive separation unit is located at a predetermined position where the drive control unit contacts the uppermost sheet material from the leading end side of the uppermost sheet material. After the predetermined stop time has elapsed, the adsorption separation unit is rotated again to turn the uppermost sheet material, and the separation assisting unit is the uppermost sheet adsorbed and held by the adsorption separation unit A technique has been proposed in which a predetermined force is applied in a direction in which a sheet material is separated from another sheet material (see, for example, Patent Document 1).

  In the conventional sheet material separating and feeding apparatus described in Patent Document 1 configured as described above, the adsorption separation is performed until the uppermost sheet material is adsorbed and separated by the adsorption separation unit and then conveyed by the sheet conveyance unit. Since the unit is stopped for a certain period of time, the adsorption force of the adsorption separation unit to the uppermost sheet material is increased by increasing the contact time between the uppermost sheet material and the adsorption separation unit, and the adsorption force to other sheet materials Can be reduced. In addition, by blowing air between the uppermost sheet material and another sheet material by the blower that constitutes the separation assisting unit, the uppermost sheet material is reliably separated, and the sheet material is not fed or heavy. Occurrence of sending etc. can be prevented.

  In addition, after blowing air to the end of the uppermost sheet material and adsorbing it to the endless belt, the front end of the sheet material adsorbed to the endless belt is moved upward by moving a moving roller provided on the conveyance belt A technique for increasing the height of the portion has been proposed (see, for example, Patent Document 2).

  In the conventional sheet material separating and feeding apparatus described in Patent Document 2 configured as described above, by increasing the height of the leading end portion of the sheet material adsorbed on the endless belt, the endless belt is formed. Air can easily enter between the front end of the uppermost sheet material that has been adsorbed and the front end of another sheet material, and the sheet material can be stably adsorbed, separated, and conveyed.

  However, in the above-described conventional sheet material separating and feeding apparatus, the uppermost sheet material and the second sheet are suppressed while suppressing the influence of the change of the sheet material type and the curling and folding of the sheet material. Although it can be separated from the material, the adsorption force between the endless belt and the sheet material tends to be small because it uses static electricity. In addition, the adsorbing power of the endless belt to the sheet material varies due to fluctuations over time, such as the adhesion of paper dust to the surface of the endless belt, and the sheet material changes due to environmental variations such as changes in the sheet material type and humidity. The electric resistance fluctuates and the attractive force of the endless belt on the sheet material tends to fluctuate. Therefore, when the impact force caused by the sheet material hitting the guide plate forming the sheet conveyance path is larger than the adsorption force of the endless belt, the sheet material is peeled off from the endless belt and enters the sheet conveyance path. However, there was a problem that a sheet feeding failure occurred.

  The present invention has been made in order to solve the above-described conventional problems. Even in various sheet types, the present invention can reliably start from a stacked sheet bundle while suppressing the influence of environmental variation and temporal variation. An object of the present invention is to provide a highly reliable sheet material separating and feeding apparatus and an image forming apparatus capable of separating and feeding sheet materials one by one.

  In order to achieve the above object, a sheet material separating and feeding apparatus according to the present invention has a sheet material stacking unit for stacking a plurality of sheet materials and an adsorbing member made of a dielectric, and is stacked on the sheet material stacking unit. The uppermost sheet material of the plurality of sheet materials is separated by the adsorption force due to the unequal electric field formed on the adsorption member, and the separated uppermost sheet material is adsorbed to the adsorption member by the adsorption force. In a sheet material separating and feeding apparatus capable of bringing the adsorbing member and the uppermost sheet material out of the stacked sheet materials into contact with and separating from each other, The separation conveyance unit is configured to have a rotating body that can contact and separate from the uppermost sheet material adsorbed by the adsorption member.

With this configuration, according to the present invention, the separation conveyance unit has a rotating body that can contact and separate from the uppermost sheet material adsorbed by the adsorption member. Even if the adsorbing force of the adsorbing member to the sheet material decreases due to the fluctuation, the sheet material is peeled off from the adsorbing member by holding the sheet material by bringing the rotating body into contact with the sheet material adsorbed on the adsorbing member Can be prevented, and the occurrence of sheet feeding failure can be prevented. Therefore, even in various sheet material types, it is possible to reliably separate and feed the sheet material one by one from the stacked sheet bundle while suppressing the influence of environmental variation and temporal variation.
In addition, since the rotating body can be brought into contact with and separated from the sheet material adsorbed by the adsorbing member, for example, the adjoining and separating of the adsorbing member and the uppermost sheet material among the stacked sheet materials is the uppermost part. When the suction member is switched by the movement of the suction member with respect to the sheet material, the rotor is prevented from interfering with the moving suction member by separating the rotor from the sheet material sucked by the suction member. Therefore, it is possible to prevent occurrence of sheet feeding failure.

  In the sheet material separating and feeding device according to the present invention, the rotating body is constituted by an elastic body.

  With this configuration, since the rotating body is constituted by an elastic body, the present invention provides a necessary gap between the adsorbing member and the rotating body in order to hold the sheet material by bringing the rotating body into contact with the adsorbing member. Can be easily formed. That is, when the rotating body is configured by a rigid body, the rotating body does not deform even when the rotating body is brought into contact with the sheet material adsorbed by the adsorption member. By adjusting the distance with high accuracy, it is necessary to form the necessary gap that changes according to the variation in the thickness of the sheet material. In particular, when the pressing force of the rotating body against the sheet material is large, the sheet material may not enter between the adsorbing member and the rotating body, and the sheet material may be poorly fed. On the other hand, when the rotating body is an elastic body, the rotating body is elastically deformed according to the pressing force of the rotating body when the rotating body is brought into contact with the sheet material adsorbed by the adsorption member. Therefore, the sheet material can enter between the adsorption member and the rotating body. For this reason, it is not necessary to adjust the distance between the suction member and the rotating body with high accuracy compared to the case where the rotating body is configured by a rigid body. The mechanism and control content necessary for adjustment can be simplified, and the manufacturing cost of the sheet material separating and feeding apparatus can be reduced.

  In the sheet material separating and feeding apparatus according to the present invention, the rotating body is constituted by a belt.

  With this configuration, since the rotating body is constituted by a belt, the present invention is more effective than the case where the rotating body is constituted by another rotating body such as a roller having a circular cross section. The nip width with the rotating body can be increased. For this reason, the sheet material adsorbed by the adsorbing member can be held more effectively than in the case where the rotating body is constituted by another rotating body such as a roller having a circular cross section, and various sheet material types can be retained. In this case, the sheet material can be reliably separated and fed one by one from the stacked sheet bundle while suppressing the influence of environmental fluctuations and temporal fluctuations. Further, since the rotating body is constituted by a belt as an elastic body, the adsorbing member and the rotating body are compared with the case where the rotating body is constituted by an elastic body having a shape other than the belt such as a roller having a circular cross section. Even if the distance between the belt and the belt is adjusted with low accuracy, the belt is elastically deformed according to the pressure of the belt, and the sheet material can easily enter between the belt and the belt. It is possible to hold the sheet material adsorbed on the substrate more effectively. Therefore, as compared with the case where the rotating body is composed of an elastic body other than the belt, the mechanism and control contents necessary for adjusting the distance between the adsorption member and the rotating body should be simplified. Therefore, the manufacturing cost of the sheet material separating and feeding apparatus can be further reduced.

  Further, in the sheet material separating and feeding apparatus according to the present invention, the sheet material transported by the separation and transport unit is further provided downstream of the separation and transport unit in the transport direction of the sheet material in the sheet material transport path. A sheet conveying section that conveys; and a tip end detection unit that is provided downstream of the sheet conveying section in the sheet material conveying direction in the sheet material conveying path, and that detects a leading end portion of the sheet material. The conveying unit is configured to separate the rotating body from the sheet material adsorbed by the adsorbing member when the leading end portion of the sheet material is detected by the leading end detection unit.

  With this configuration, the separation conveying unit separates the rotating body from the sheet material adsorbed by the adsorbing member when the leading end detection unit detects the leading end of the sheet material. Until the sheet material conveyed by the conveyance unit starts to be conveyed by the sheet conveyance unit, the rotating body is brought into contact with the sheet material adsorbed by the adsorption member to hold the sheet material adsorbed by the adsorption member. be able to. Therefore, until the sheet material conveyed by the separation conveyance unit starts to be conveyed by the sheet conveyance unit, the sheet material can be prevented from being peeled off from the adsorption member, and thus the sheet material is reliably conveyed to the sheet conveyance unit. It is possible to prevent the sheet material from being poorly fed.

  Further, in the sheet material separating and feeding apparatus according to the present invention, the separation conveyance unit moves the rotating body between a position where the rotating body is in contact with the sheet material adsorbed by the adsorption member and a position where the rotation body is separated. Has a motor.

  With this configuration, the present invention has a moving motor that moves the separation body between a position where the rotating body abuts against the sheet material adsorbed by the adsorbing member and a position where it separates. By controlling the motor, the position of the rotating body with respect to the sheet material adsorbed by the adsorbing member can be easily adjusted, and the rotating body can be easily brought into and out of contact with the sheet material adsorbed by the adsorbing member. . Therefore, since the sheet material adsorbed by the adsorbing member can be easily held, the sheet material can be reliably conveyed, and the occurrence of sheet feeding failure can be prevented.

  An image forming apparatus according to the present invention includes the above-described sheet material separating and feeding device.

  With this configuration, the present invention is a sheet material that can reliably separate and feed the sheet material one by one from the stacked sheet bundle while suppressing environmental fluctuations and temporal fluctuations even in various sheet material types. An image forming apparatus equipped with a separation feeding device can be provided.

  The present invention has high reliability that can reliably separate and feed sheet materials one by one from a stacked sheet bundle while suppressing the influence of environmental fluctuations and temporal fluctuations even in various sheet material types. A sheet material separating and feeding apparatus and an image forming apparatus can be provided.

1 is a schematic configuration diagram of a copying machine including a sheet material separating and feeding device according to a first embodiment of the present invention. 1 is a perspective view showing a sheet material separating and feeding device according to a first embodiment of the present invention. It is a side view showing the sheet material separation feeding device concerning a 1st embodiment of the present invention. 1 is a partial perspective view illustrating a sheet material separating and feeding device according to a first embodiment of the present invention. (A) is a partial perspective view of a state provided with a blade-shaped charging electrode, and (b) is a partial perspective view of a state provided with a roller-shaped charging electrode. It is a schematic block diagram which shows a part of main body control part of the sheet material separation feeding apparatus which concerns on the 1st Embodiment of this invention. It is a figure which shows the sheet material separation feeding apparatus which concerns on the 1st Embodiment of this invention, Comprising: It is a partial side view at the time of providing a static elimination electrode. It is a figure which shows the sheet material separation feeding apparatus concerning the 1st Embodiment of this invention, Comprising: It is a partial side view at the time of providing a pushing-up member. It is a figure which shows the sheet material separation feeding apparatus concerning the 1st Embodiment of this invention, Comprising: It is a partial side view at the time of providing a position detection sensor and a sheet | seat pushing-up part. It is a figure which shows the sheet | seat material separation feeding apparatus which concerns on the 1st Embodiment of this invention, Comprising: It is a partial side view at the time of comprising an electrostatic attraction / separation part so that a vertical movement and rotation are possible. It is a figure which shows the sheet | seat material separation feeding apparatus which concerns on the 1st Embodiment of this invention, Comprising: It is a partial side view at the time of providing an electrostatic adsorption separation part with the separation nail | claw. It is a perspective view for demonstrating the formation method of the other electric charge pattern of the electrostatic attraction separation part of the sheet | seat material separation feeding apparatus which concerns on the 1st Embodiment of this invention. It is a time chart which shows the example of the voltage waveform for electrification and static elimination of the sheet material separation feeding apparatus concerning a 1st embodiment of the present invention. 6 is a flowchart illustrating a program process of a sheet material holding operation executed in a main body control unit of the image forming apparatus including the sheet material separating and feeding apparatus according to the first embodiment of the present invention. It is a side view which shows the sheet | seat material separation feeding apparatus which concerns on the 2nd Embodiment of this invention. 10 is a flowchart showing a program process of a sheet material holding operation executed in a main body control unit of an image forming apparatus provided with a sheet material separation and feeding apparatus according to a second embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
1 to 13 are diagrams showing a first embodiment of a sheet material separating and feeding apparatus and an image forming apparatus according to the present invention, showing an example in which the image forming apparatus is applied to an electrophotographic copying machine. ing.

First, the configuration will be described.
As shown in FIG. 1, the image forming apparatus 1 configured as a copying machine includes a document reading unit 2 that reads a document, and a document with respect to an uppermost sheet material (recording paper) 6 a fed from a sheet feeding unit 4. An image forming unit 3 that forms an image read by the reading unit 2 and a sheet feeding unit 4 that feeds a sheet material 6a to the image forming unit 3 are provided. In the image forming apparatus according to the present embodiment, the image forming unit 3 and the paper feeding unit 4 can be divided.

  The image forming unit 3 includes four image forming units 124 (124Y (yellow), 124C (cyan), 124M (magenta), 124Bk (black)), an intermediate transfer belt 125 that is a transfer belt, and an exposure device 126. Have.

  The image forming units 124Y, 124C, 124M, and 124Bk are a photoconductor 127 (127Y, 127C, 127M, and 127Bk) that is an image carrier that is driven to rotate in the clockwise direction, and a charging unit 128 that is disposed around the photoconductor 127. The developing unit 129, the cleaning unit 130, and the like are configured to form images of different colors (toner images).

  The photoconductor 127 is formed in a cylindrical shape and is rotationally driven by a drive source (not shown). A photosensitive layer is provided on the outer peripheral surface portion of the photoconductor 127, and a light beam indicated by a broken line emitted from the exposure device 126 is spot-irradiated on the outer peripheral surface of the photoconductor 127, whereby the outer peripheral surface of the photoconductor 127 is exposed. The electrostatic latent image corresponding to the image information is written.

  The charging unit 128 uniformly charges the outer peripheral surface of the photoconductor 127, and a contact type is used for the photoconductor 127. The developing unit 129 supplies toner to the photoconductor 127, and the supplied toner adheres to the electrostatic latent image written on the outer peripheral surface of the photoconductor 127, whereby the electrostatic latent image on the photoconductor 127 is changed. A toner image is visualized, and a non-contact type is used for the photoreceptor 127.

  The cleaning unit 130 removes residual toner adhering to the outer peripheral surface of the photoconductor 127, and a brush contact type in which a brush contacts the outer peripheral surface of the photoconductor 127 is employed.

  The intermediate transfer belt 125 is composed of an endless belt formed with a resin film or rubber as a base, and a toner image formed on the photoreceptor 127 is transferred to the intermediate transfer belt 125. Further, the toner image transferred to the intermediate transfer belt 125 is transferred to the sheet material 6 a by the transfer roller 9.

  The exposure device 126 converts color-separated image data input from a personal computer, a word processor, or the like, or image data of a document read by the document reading unit 2 into a signal for driving a light source, and accordingly, each laser light source unit. The semiconductor laser is driven to emit a light beam.

  The paper feeding unit 4 has a paper feeding device 5 as a sheet material separating and feeding device, and this paper feeding device 5 is arranged on the uppermost side from a plurality of sheet bundles 6 stacked on a paper feeding tray to be described later. It has a separation unit 7 that sucks the sheet material 6a positioned and feeds it to the downstream side in the transport direction. Here, the separation unit 7 constitutes a separation transport unit according to the present invention.

  The sheet material 6 a separated by the paper feeding device 5 is conveyed into the conveyance path 50, and the sheet material 6 a conveyed to the conveyance path 50 is further conveyed by the conveyance roller pair 8. It has become. The sheet material 6 a conveyed by the conveyance roller pair 8 is adapted to transfer the toner image formed by the image forming unit 3 by the transfer roller 9. Further, the sheet material 6 a onto which the toner image has been transferred by the transfer roller 9 is thermally transferred by the fixing device 10 and is discharged to the discharge tray 12 by the discharge roller pair 11.

  In addition to the above-described electrophotographic system, the image forming apparatus 1 may employ other systems such as an ink jet system. In addition to being configured as a copying machine, the image forming apparatus 1 may be a facsimile machine, a printing machine, or a multifunction machine. You may comprise as.

  As shown in FIG. 2, the sheet feeding device 5 includes a sheet feeding tray 16 that constitutes a sheet material stacking unit, which will be described later, and an electrostatic adsorption separation unit 14 that constitutes a separation unit 7 (see FIG. 1). Yes. The electrostatic adsorption separation unit 14 is shorter than the stackable sheet width and is disposed near the center in the width direction of the sheet bundle 6 stacked on the sheet feed tray 16, but is equal to the stackable sheet width. Or it may be long. Further, although one electrostatic adsorption separation unit 14 is illustrated in FIG. 2, a plurality of electrostatic adsorption separation units 14 may be arranged in the width direction of the stacked sheet bundle 6.

  As illustrated in FIG. 3, the sheet feeding device 5 according to the present embodiment includes a separation unit 7, a sheet material stacking unit 15, and a sheet conveyance unit 60. Further, the separation unit 7 described above includes an electrostatic adsorption separation unit 14 and a sheet material conveyance auxiliary unit 70.

  As shown in FIG. 3, the electrostatic adsorption separation unit 14 includes a driving roller 17, a driven roller 18, an endless belt 19 made of a dielectric wound around the driving roller 17 and the driven roller 18, and a belt 19. And a charging power source 24 connected to the charging electrode 21. Further, the electrostatic adsorption separation unit 14 includes a drive motor 81, a contact / separation solenoid 82, and an electromagnetic clutch 86.

As shown in FIG. 4A, the driving roller 17 is driven to rotate around a driving shaft 17a by a driving force of a driving motor, which will be described later, so that the belt 19 rotates. The surface of the drive roller 17 is composed of a conductive rubber layer having a resistance value of about 10 ⁶ Ω · cm. Furthermore, the diameter of the driving roller 17 is a small diameter suitable for separating the sheet material 6a (see FIG. 3) from the belt 19 by the curvature. That is, by setting the diameter of the driving roller 17 to be small and increasing the curvature, the sheet material 6a that is attracted to the belt 19 and separated and conveyed is separated from the driving roller 17, and the conveying path 50 on the downstream side in the conveying direction. (See FIG. 3).

  Further, as shown in FIG. 4A, the driven roller 18 is a metal roller whose surface and inside are made of metal, and the rotating shaft 18a rotates as the belt 19 circulates as the drive roller 17 is driven. To follow.

  The drive shaft 17a of the drive roller 17 and the rotation shaft 18a of the driven roller 18 are rotatably supported by a support member (not shown) for regulating the distance between the drive roller 17 and the driven roller 18. Further, the driving roller 17 and the driven roller 18 are grounded.

Referring to FIG. 3 again, the belt 19 is made of a dielectric having a predetermined resistance, for example, a film such as polyethylene terephthalate having a thickness of about 100 μm, and the resistance is 10 ⁸ Ω · cm or more. And a back layer 19b made of a conductor having a resistance of 10 ⁶ Ω · cm or less. As a result, the belt 19 is in a favorable charged state. Further, the belt 19 is set at a position where the adsorption area of the sheet material 6 a located at the uppermost portion can be sufficiently taken with respect to the sheet bundle 6.

  The charging electrode 21 is constituted by a blade-like electrode disposed so as to abut on the surface layer 19a of the belt 19 near the position where the belt 19 is wound around the driving roller 17, and serves as a charging power source 24 that generates alternating current. It is connected. The charging electrode 21 uses the back layer 19b of the belt 19 that is grounded via the driving roller 17 and the driven roller 18 as a counter electrode. Therefore, the charging electrode 21 is disposed anywhere as long as it is in contact with the surface layer 19a of the belt 19. May be.

  The charging electrode 21 is not limited to the blade-shaped charging electrode 21 shown in FIG. 4A, but may be configured by the roller-shaped charging electrode 23 shown in FIG. 4B. The electrode 21 has an advantage that it can be manufactured at a lower cost than the roller-shaped charging electrode 23.

  The charging power source 24 is constituted by an AC power source, the positive electrode is connected to the charging electrode 21 and the negative electrode is grounded.

  The drive motor 81 is configured by a stepping motor, and drives the drive roller 17 to rotate based on a control signal output by a main body control unit described later.

  The contact / separation solenoid 82 raises and lowers the electrostatic adsorption separation unit 14 in the direction of the arrow 51 in FIG. 3 via the arm member 82a based on a control signal output from a main body control unit described later. Yes.

  The arm member 82 a has one end attached to a support member (not shown) for regulating the distance between the driving roller 17 and the driven roller 18, and the other end attached to the contact / separation solenoid 82.

  The electromagnetic clutch 86 is provided between the drive motor 81 and the drive shaft 17a, and is a connection for transmitting power between the drive motor 81 and the drive shaft 17a based on a control signal output by a main body control unit described later. It is controlled between a state and a cut-off state that cuts off the transmission of power. Further, the electromagnetic clutch 86 is controlled to be in a connected state until the sheet material 6a is conveyed to the conveyance roller pair 8, and is controlled to be disconnected when the sheet material 6a reaches the conveyance roller pair 8. Yes. As a result, when the sheet material 6a reaches the conveying roller pair 8, the drive shaft 17a shown in FIG. 4A is free to rotate, and the load on the drive roller 17 generated in the separation unit 7 is reduced. ing.

  The sheet material conveyance assisting unit 70 according to the present embodiment includes a holding roller 72, an arm 73, a moving motor 84, and a gear 84g.

  The holding roller 72 is constituted by a two-layer roller of EPDM (ethylene / propylene copolymer) rubber as an elastic body, and is supported by an arm 73 so as to be rotatable and movable in the direction of an arrow 54. Further, the holding roller 72 is driven with respect to the belt 19. The material of the holding roller 72 is not limited to the EPDM rubber, and an elastic material having a low hygroscopic property such as chloroprene rubber, silicon rubber, epichloro rubber, or the like can be applied. Here, the holding roller 72 constitutes a rotating body according to the present invention.

  The movement motor 84 is constituted by a stepping motor, and rotates a gear 84g connected to the movement motor 84 based on a control signal output from a main body control unit described later.

  The gear 84g is connected to the arm 73 and the moving motor 84, and is driven to rotate by the moving motor 84, thereby swinging the arm 73 in the direction of the arrow 54. Accordingly, the moving motor 84 causes the holding roller 72 to move to the endless dielectric belt position Pa where the sheet material 6a adsorbed to the belt 19 and the holding roller 72 abut, and the sheet material 6a adsorbed to the belt 19 and the holding roller. 72 is moved between the initial position Pb and the initial position Pb.

  The gear 84g and the arm 73 have been described as being configured separately, but may be configured integrally.

  The sheet material stacking unit 15 has a paper feed tray 16. The paper feed tray 16 is configured to be able to be pulled out and pulled into the housing of the paper feed unit 4, and has a bottom plate 28 on which the sheet bundle 6 is stacked.

  The sheet conveyance unit 60 includes a pair of guide plates 61 and 62 and a pair of conveyance rollers 65 and 66 that are rotatably supported by the guide plates 61 and 62 and constitute the conveyance roller pair 8. The conveyance rollers 65 and 66 are rotationally driven by a conveyance motor (not shown), and further convey the sheet material 6a conveyed by the separation unit 7 to the image forming unit 3 (see FIG. 1). ing.

Here, the position where the sheet material 6a adsorbed to the belt 19 and the holding roller 72 abut,
The distance between the positions where the conveyance rollers 65 and 66 are provided is configured to be smaller than the size of the sheet material in the direction of the conveyance path 50. For this reason, the sheet material 6a conveyed by the electrostatic adsorption separation unit 14 is supported by at least one of the holding roller 72 and the conveyance rollers 65 and 66.

  In addition, the sheet feeding device 5 includes a position detection sensor 91 and a tip end detection sensor 92. The position detection sensor 91 detects the position P of the uppermost sheet material 6 a in the direction of the arrow 51 in FIG. 3 and outputs a detection signal to the main body control unit 100.

  The leading end detection sensor 92 is provided on the downstream side of the sheet conveying unit 60 in the conveying direction of the sheet material in the conveying path 50, and detects the leading end of the sheet material 6a conveyed by the conveying rollers 65 and 66 in the conveying direction. The detection signal is output to a main body control unit described later. An example of the form of the tip detection sensor 92 is an ultrasonic sensor. The difference between the time when a transmission wave is transmitted from a sensor head (not shown) and the time when a reception wave reflected and returned is received by the sensor head. Based on this change, the leading end of the sheet material 6a in the conveying direction is detected. In addition, the front-end | tip part detection sensor 92 may be comprised with the optical sensor and the magnetic sensor other than the ultrasonic sensor. Here, the tip detection sensor 92 constitutes tip detection means according to the present invention.

  As shown in FIG. 5, the image forming apparatus 1 includes a main body control unit 100 and an operation input unit 101.

  The main body control unit 100 is composed of a microcomputer including a CPU, ROM, RAM, I / O interface, and the like, and a program stored in advance in the ROM is executed by the CPU.

  The main body control unit 100 includes a charging power source 24, a drive motor 81, a contact / separation solenoid 82, a moving motor 84, an electromagnetic clutch 86, a position detection sensor 91, a tip detection sensor 92, an operation input unit 101, and other image forming apparatuses 1. Are connected to various sensors, motors, and the like. Further, the main body control unit 100 controls the charging power supply 24, the motors such as the drive motor 81, and the electromagnetic clutch 86 based on detection signals from various sensors so as to control a sheet material holding operation and the like to be described later. It has become.

  The operation input unit 101 is provided in the main body of the image forming apparatus 1 and includes various keys such as a numeric keypad and a print start key and various displays. Further, the operation input unit 101 responds to the sheet information by inputting the sheet information such as the material or size of the sheet material separated and fed by the sheet feeding device 5 by the user or by selecting the sheet using a selection button or the like. A detection signal is output to the main body control unit 100. Further, the operation input unit 101 displays an error when there is a malfunction of the image forming apparatus 1 or the like.

  As shown in FIG. 6, the electrostatic adsorption separation unit 14 may further include a charge removal electrode 22 and a charge removal power supply 25 in addition to the charge electrode 21 and the charge power supply 24. In this case, the neutralizing electrode 22 is an alternating power source that is an alternating power source on the upstream side in the rotational direction of the belt 19 with respect to the charging electrode 21 and on the downstream side in the rotational direction of the belt 19 with respect to the separation position of the sheet bundle 6 and the belt 19. In the state of being connected to the belt 25, the belt 19 is placed in contact with or close to the belt 19. The charging power source 24 and the neutralizing power source 25 are controlled so that the suction force on the belt 19 is removed at the position where the leading end of the sheet material 6 a contacts the conveying roller pair 8.

  As shown in FIG. 7, in the sheet material stacking portion 15, the bottom plate 28 rotates about the rotation fulcrum 28d as a fulcrum by the urging force in the direction of the arrow 56 by the push-up member 27 constituted by a coil spring. May be. In this case, the belt 19, the driving roller 17, and the driven roller 18 are supported so that their postures can be changed according to the inclination change of the bottom plate 28. Specifically, the rotation shaft 18a (see FIG. 4) of the driven roller 18 is supported by the housing of the image forming apparatus 1 (see FIG. 1), unlike the drive shaft 17a (see FIG. 4) of the drive roller 17. However, it can be rotated in the direction of the arrow 55 with the drive shaft 17a of the drive roller 17 as a rotation fulcrum. The driven roller 18 is lowered by its own weight in a direction close to the uppermost sheet material 6a (see FIG. 2) of the sheet bundle 6 stacked on the sheet feeding tray 16.

  The belt 19 is positioned at the upper front end of the uppermost sheet material 6a of the sheet bundle 6 on the bottom plate 28 pushed up by the push-up member 27 with the driving roller 17 as an axis, and can contact the sheet material 6a. Be placed. The bottom plate 28 urges the sheet material 6a against the belt 19 by lifting the other end so that the bottom plate 28 can be rotated by a push-up member 27 with a rotation fulcrum 28d formed at one end as a fulcrum. .

  As shown in FIG. 8, the sheet material stacking unit 15 may include a sheet push-up unit 29 and a paper feed tray lifting / lowering motor 83.

  The sheet push-up unit 29 is interposed between a bottom plate (not shown) of the paper feed tray 16 and the bottom plate 28, and includes a rack 29 a attached to the lower surface of the bottom plate 28 and a pinion 29 b that meshes with the rack 29 a. ing.

  The bottom plate 28 is attached to the paper feed tray 16 by slidingly engaging the rack 29a with a cylindrical portion (not shown) protruding from the bottom plate 28, thereby feeding the bottom plate 28 through the rack 29a. It may be attached to the tray 16. The bottom plate 28 is slidably engaged with the side plates at both ends in the width direction of the paper feed tray 16 so that the bottom plate 28 is attached to the paper feed tray 16 via the rack 29a. Also good.

  The paper feed tray lifting / lowering motor 83 is constituted by a stepping motor connected to the main body control unit 100. Based on the control signal output by the main body control unit 100 (see FIG. 5), the pinion 29b is changed to the one shown in FIG. It is driven to rotate in the direction of arrow 52. For this reason, the paper feed tray lifting / lowering motor 83 is configured to lift and lower the bottom plate 28 in the direction of the arrow 53 through the rack 29a while maintaining the parallelism by rotationally driving the pinion 29b.

  In this case, the electrostatic attraction / separation unit 14 may be configured such that the positions of the driving roller 17, the driven roller 18, and the belt 19 are fixed in the paper feeding device 5. The sheet feeding device 5 rotates the pinion 29b by controlling the sheet feeding tray lifting / lowering motor 83 by the main body control unit 100 based on the position P of the sheet material 6a detected by the position detection sensor 91. The distance between the belt 19 and the sheet material 6a and the contact pressure can be appropriately controlled.

  As shown in FIG. 9, the sheet material stacking portion 15 is fixed when the bottom plate 28 is moved up and down while keeping parallel by the rack and pinion type sheet pushing-up portion 29, and also fixed while keeping parallel. The electrostatic attraction / separation unit 14 is configured to move in the direction of the arrow 51 by the contact / separation solenoid 82 (see FIG. 3). Further, the electrostatic adsorption separation unit 14 may be configured such that the driven roller 18 is rotated in the direction of the arrow 57 by a motor (not shown) with the driving roller 17 as a rotation fulcrum. Thereby, the electrostatic adsorption separation unit 14 causes the uppermost sheet material 6a to be adsorbed to the belt 19, and the second sheet material 6b is separated from the uppermost sheet material 6a by the rigidity of the sheet, so-called sheet stiffness. By peeling, the sheet material is turned.

  In addition, since it is necessary to make the belt 19 circulate when charging or discharging the belt 19, when the belt 19 is in contact with the sheet material 6a, the sheet material 6a is adsorbed along with the lap of the belt 19, There is a risk of being transported. For this reason, it is possible to arbitrarily adjust the contact and separation between the belt 19 and the sheet material 6a by allowing the electrostatic adsorption separation unit 14 or the bottom plate 28 to move in the direction of the arrow 51 or the direction of the arrow 53, respectively. Yes.

  Further, when the electrostatic adsorption separation unit 14 is moved in the direction of the arrow 51 and when the bottom plate 28 is moved in the direction of the arrow 53, the case where the electrostatic adsorption separation unit 14 is moved is moved to the bottom plate 28. Since the disturbance of the stacked sheet bundle 6 is suppressed, it is preferable to move the bottom plate 28 in the direction of the arrow 53.

  As shown in FIG. 10, the belt 19 prevents the second sheet material 6 b from being attracted to the belt 19 before the rear end of the sheet material 6 a reaches the position where the driven roller 18 and the sheet bundle 6 are opposed to each other. .

  The separation of the sheet material 6a from the belt 19 at the portion of the driving roller 17 depends on the curvature of the belt 19 at the portion suspended from the driving roller 17, but in order to further ensure the separation, as shown in FIG. A nail 32 may be provided. The separation claw 32 is constituted by a plate-like member that is curved with a predetermined curvature and has a plate thickness that decreases toward the tip, and is disposed in a state of being slightly separated from the outer peripheral surface of the belt 19. The separation claw 32 makes the separation of the sheet material 6a from the belt 19 more reliable by allowing the tip portion having the smallest plate thickness to enter between the belt 19 and the sheet material 6a.

  The sheet material 6a is conveyed by only the conveying force of the conveying roller pair 8 without being affected by the belt 19 after being sandwiched between the conveying roller pair 8 (see FIG. 3). Further, in order to prevent paper dust and other dust from adversely affecting the adsorption operation of the electrostatic adsorption separation unit 14, the electrostatic adsorption separation unit 14 has a cleaning mechanism (not shown) for cleaning the belt 19. ing. In the above description, an electric field is applied to the belt 19 by applying an electric charge to the belt 19 by a blade-like electrode as shown in FIG. 4A or a roller-like electrode as shown in FIG. However, the method of applying the electric charge to the belt 19 is not limited to this, and the brush-like electrode may be brought into contact with the belt 19, and the sawtooth-like electrode is attached to the belt 19. You may arrange | position in the state separated only by very small distance.

  Further, as shown in FIG. 11, the electrostatic adsorption separation unit 14 is disposed on the belt 19 so that the positive and negative comb-like electrodes 40 face each other in a direction orthogonal to the circumferential direction of the belt 19. You may be comprised so that. In this case, at both ends of the belt 19, there are power-supplied portions 41 with exposed patterns, and a positive or negative high-voltage power source 42 applies a positive or negative voltage to the electrode 40 through the power-supplied portion 41. An electric field is generated, and a force for adsorbing the sheet material 6a is generated.

  In the paper feeding device 5 configured as described above, for example, a control signal (paper feeding signal) output from the main body control unit 100 when a print start key (not shown) provided in the operation input unit 101 is pressed. Thus, when the electromagnetic clutch 86 is controlled to be in the connected state, the driving roller 17 is driven to rotate. An alternating voltage is applied from the charging power source 24 via the charging electrode 21 to the belt 19 that has started to circulate along with the rotation of the drive roller 17, and the surface of the belt 19 has an AC power source frequency and a rotating speed of the belt 19. An alternating charge pattern is formed at a corresponding pitch (pitch should be about 2 mm to 15 mm). The charging power source 24 may be an alternating current or a direct current having a high and low alternating potential. In this embodiment, the charging power supply 24 has an amplitude of 3 to 4 kV (± 1.5 to ± 2) with respect to the surface of the belt 19. AC is applied.

  Here, as shown in FIG. 12A, the sheet feeding device 5 can perform charging and discharging by controlling the applied voltage V of the charging power supply 24 and the discharging power supply 25, and lowers the applied voltage V. As a result, the charge pattern on the belt 19 is removed (static elimination). FIG. 12B shows an example in which the power supply frequency is increased to reduce the pitch of the charge pattern formed on the belt 19 and reduce the adsorption force of the belt 19 based on Maxwell stress. These are square waves in which a DC power supply is alternated, but the same applies when an AC power supply is used as shown in FIGS. 12 (c) and 12 (d).

  The belt 19 on which the charge pattern is formed is in contact with the upper surface front end portion of the uppermost sheet material 6a at a position wound around the driven roller 18. Thus, Maxwell's stress is applied to the sheet material 6a, which is a dielectric, due to an unequal electric field formed by the charge pattern on the surface of the belt 19. Further, after only the uppermost sheet material 6a is attracted, held and conveyed to the belt 19, the uppermost sheet material 6a is separated by the curvature of the belt 19 in the portion suspended from the driving roller 17, and in the conveying direction. It is conveyed and conveyed to the image forming unit 3 (see FIG. 1) through the conveying path 50 by the conveying roller pair 8.

  The adsorbing force by the charge pattern acts on the sheet material 6a other than the uppermost sheet material 6a for a certain period from the moment when the sheet material 6a is adsorbed to the belt 19, but after the certain time has elapsed, the uppermost sheet material 6a. Only acts on the second sheet material 6b and below. In other words, the uppermost sheet material 6 a can be separated from the sheet bundle 6 without a separate member for preventing the multi-feeding of the sheet material by providing time. The linear speeds of the conveying roller pair 8 and the belt 19 are adjusted to be the same, and when the conveying roller pair 8 is intermittently driven with timing, the belt 19 is also controlled to be intermittently driven. Is done.

  Here, in the electrostatic adsorption separation method employed by the electrostatic adsorption separation unit 14, when the electric resistance of the sheet material 6a is large, it takes time to obtain an adsorption force necessary for the adsorption separation, or two sheets There is a problem that it takes time to reduce the attractive force acting on the sheet material 6b and below of the eyes. On the other hand, when the electrical resistance of the sheet material 6a is small, there is a problem that the adsorption force is small.

  The electrical resistance of the sheet material 6a varies depending on the material and moisture content of the sheet material 6a. For this reason, the main body control unit 100 (see FIG. 5) calculates from the environmental condition such as the material of the sheet material 6a input by the user from the operation input unit 101 (see FIG. 5) and the humidity detected by a thermohygrometer (not shown). Based on the moisture content of the sheet material 6a, the charging power source 24 (see FIG. 2) is controlled to adjust the suction force of the belt 19, so that the variation in environmental conditions is within the range of the electrostatic suction force. Thus, the sheet material 6a can be stably adsorbed, separated and conveyed.

  Next, the sheet material holding operation of the sheet feeding device 5 according to the present embodiment will be described with reference to FIGS. The flowchart shown in FIG. 13 represents the execution contents of a program for holding a sheet material that is executed by the main body control unit 100 using the RAM as a work area. The program for holding the sheet material is executed at predetermined time intervals when the main body control unit 100 separates and conveys the sheet material by the sheet feeding device 5.

  As shown in FIG. 13, the main body control unit 100 determines whether or not the position of the sheet bundle 6 has been raised (step S11). Specifically, the main body control unit 100 determines a predetermined distance d from the value when the position P of the uppermost sheet material 6a detected by the position detection sensor 91 sucks and separates the sheet material 6a last time. And the position of the sheet bundle 6 is determined to have risen when it is higher than the predetermined position P1. Here, the predetermined position P1 is a value that is theoretically or experimentally determined in advance so that the belt 19 contacts the uppermost sheet material 6a with an optimum pressure.

  When the main body control unit 100 determines that the position of the sheet bundle 6 has been raised (YES in step S11), the main body control unit 100 controls the moving motor 84 to swing the arm 73, thereby moving the holding roller 72 to the endless dielectric belt. Move to position Pa (step S12).

  Next, the main body control unit 100 determines whether or not the leading end portion of the sheet material 6a has passed through the conveyance rollers 65 and 66 (step S13). Specifically, the main body control unit 100 determines whether or not the leading end portion of the sheet material 6a has passed the conveying rollers 65 and 66 based on the detection signal of the leading end detection sensor 92.

  When the main body control unit 100 determines that the leading end portion of the sheet material 6a has passed the conveying rollers 65 and 66 (YES in step S13), the main body control unit 100 controls the moving motor 84 to swing the arm 73 to hold it. The roller 72 is moved to the initial position Pb (step S14), and this process is terminated.

  When the main body control unit 100 determines that the position of the sheet bundle 6 has not risen (NO in step S11), and when it determines that the leading end of the sheet material 6a has not passed the transport rollers 65 and 66, (NO in step S13), error display is performed (step S15). Specifically, the main body control unit 100 displays an error message “Please reset the paper feed tray” on the operation input unit 101. The main body control unit 100 may display not only the text but also a graphic representing the resetting of the paper feed tray 16 on the operation input unit 101.

  The main body control unit 100 performs error processing after displaying an error (step S16). Specifically, the main body control unit 100 resets the error display displayed on the operation input unit 101 when the paper feed tray 16 is reset.

  As described above, in the sheet feeding device 5 according to the present embodiment, the separation unit 7 includes the holding roller 72 that can come into contact with and separate from the uppermost sheet material 6a adsorbed by the adsorption member. Even if the adsorption force of the belt 19 to the sheet material 6a becomes small due to the change of the sheet material type, the environmental variation, and the variation with time, the holding roller 72 is brought into contact with the sheet material 6a adsorbed to the belt 19 to make the sheet material 6a. By holding the sheet material 6a, it is possible to prevent the sheet material 6a from being peeled off from the belt 19, and to prevent the sheet material from being poorly fed. Therefore, even in various sheet material types, it is possible to reliably separate and feed the sheet material one by one from the stacked sheet bundle while suppressing the influence of environmental variation and temporal variation.

  Further, since the holding roller 72 can be brought into contact with and separated from the sheet material 6a adsorbed to the belt 19, for example, the contact between the belt 19 and the uppermost sheet material 6a of the stacked sheet bundle 6 is made. However, when the electrostatic adsorption separation unit 14 is switched with respect to the uppermost sheet material 6 a by moving in the direction of the arrow 51, the holding roller 72 is separated from the sheet material 6 a adsorbed to the belt 19. As a result, it is possible to prevent the holding roller 72 from interfering with the moving belt 19, and thus it is possible to prevent the sheet material from being poorly fed.

  In the sheet feeding device 5 according to the present embodiment, since the holding roller 72 is formed of an elastic body, the holding roller 72 is held by the belt 19 in order to hold the sheet material 6a by bringing the holding roller 72 into contact with the belt 19. A necessary gap can be easily formed between the roller 72 and the roller 72. That is, when the holding roller 72 is formed of a rigid body, the holding roller 72 is not deformed even when the holding roller 72 is brought into contact with the sheet material 6 a adsorbed to the belt 19. By adjusting the distance to 72 with high accuracy, it is necessary to form the necessary gap that changes according to the variation in the thickness of the sheet material 6a. In particular, when the pressing force of the holding roller 72 against the sheet material 6 a is large, the sheet material 6 a may not enter between the belt 19 and the holding roller 72, and there is a possibility that a sheet material feeding failure may occur.

  On the other hand, in the present embodiment, since the holding roller 72 is made of an elastic body, the pressing force of the holding roller 72 when the holding roller 72 is brought into contact with the sheet material 6 a adsorbed to the belt 19. Accordingly, the holding roller 72 is elastically deformed, and the sheet material 6 a can enter between the belt 19 and the holding roller 72. Therefore, it is not necessary to adjust the distance between the belt 19 and the holding roller 72 with high accuracy as compared with the case where the holding roller 72 is formed of a rigid body. The mechanism and control contents necessary for adjusting the distance can be simplified, and the manufacturing cost of the sheet feeding device 5 can be reduced.

  Further, in the sheet feeding device 5 according to the present embodiment, when the separation unit 7 detects the leading end portion of the sheet material 6a by the leading end detection sensor 92, the holding roller 72 is attracted to the belt 19 by the sheet. Since the sheet 6a is separated from the sheet 6a, the holding roller 72 is brought into contact with the sheet 6a adsorbed to the belt 19 until the sheet 6a conveyed by the separation unit 7 starts to be conveyed by the sheet conveying unit 60. Thus, the sheet material 6a adsorbed to the belt 19 can be held.

  Therefore, it is possible to prevent the sheet material 6a from being peeled off from the belt 19 until the sheet material 6a conveyed by the separation unit 7 starts to be conveyed by the sheet conveyance unit 60, so that the sheet material 6a is reliably conveyed. It can be conveyed to the section 60, and the occurrence of sheet feeding failure can be prevented.

  Further, in the sheet feeding device 5 according to the present embodiment, the separating unit 7 has an endless dielectric belt position Pa where the holding roller 72 contacts the sheet material 6a adsorbed to the belt 19 and an initial position Pb where the separating roller 7 is separated. Therefore, by controlling the movement motor 84, the position of the holding roller 72 with respect to the sheet material 6a adsorbed to the belt 19 can be easily adjusted. The holding roller 72 can be easily brought into and out of contact with the sheet material 6a adsorbed to the sheet 19.

  Therefore, since the sheet material 6a adsorbed to the belt 19 can be easily held, the sheet material 6a can be reliably conveyed, and the occurrence of sheet feeding failure can be prevented.

  Furthermore, the present invention provides a sheet feeding device capable of reliably separating and feeding sheet materials one by one from the stacked sheet bundle 6 while suppressing environmental fluctuations and temporal changes even in various sheet material types. 5 can be provided.

  The sheet feeding device 5 according to the first embodiment described above is configured to hold the sheet material 6a adsorbed to the belt 19 by the holding roller 72 of the sheet material conveyance auxiliary unit 70, which will be described below. As in the sheet feeding device 5 according to the second embodiment, the sheet material 6a adsorbed to the belt 19 may be held by a holding belt.

(Second Embodiment)
Hereinafter, a second embodiment of the present invention will be described with reference to the drawings.
First, the configuration will be described.

  The same components as those of the paper feeding device 5 according to the first embodiment are described using the same reference numerals as those of the paper feeding device 5 according to the first embodiment shown in FIGS. 1 to 13. In particular, only the differences will be described in detail.

  As illustrated in FIG. 14, the sheet material conveyance assisting unit 71 according to the present embodiment includes an arm 74 having one end connected to the gear 84 g, a bracket 75 connected to the other end of the arm 74, and one end of the bracket 75. A driving side holding roller 76 rotatably supported on the other end of the bracket 75, a driven side holding roller 77 rotatably supported on the other end of the bracket 75, and a holding belt suspended on the driving side holding roller 76 and the driven side holding roller 77. 78, a holding belt motor 79 composed of a stepping motor fixed to the casing of the image forming apparatus 1, a timing belt 80 suspended from the driving side holding roller 76 and the holding belt motor 79, the above-described moving motor 84, and And a gear 84g.

  The bracket 75 is connected to the rotating shaft of the driving side holding roller 76 and the rotating shaft of the driven side holding roller 77, and maintains a constant distance between the driving side holding roller 76 and the driven side holding roller 77. ing.

  Each of the driving side holding roller 76 and the driven side holding roller 77 is made of a resin mainly composed of polyacetal, and is supported so as to be rotatable about a rotation shaft. The driving side holding roller 76 and the driven side holding roller 77 are not limited to polyacetal, but polyamide (PA), polycarbonate (PC), polyphenyl ether (PPE), polybutylene terephthalate (PBT), or ultrahigh molecular weight polyethylene (UHPE). Engineering plastics such as) can be used. Further, depending on the usage environment of each roller, different resins may be used for each roller, or a plurality of materials may be used for one roller.

  The holding belt 78 is constituted by an EPDM (ethylene / propylene copolymer) rubber belt as an elastic body, and can be circulated while being suspended by the driving side holding roller 76 and the driven side holding roller 77. The material of the holding roller 72 is not limited to the EPDM rubber, and an elastic material having a low hygroscopic property such as chloroprene rubber, silicon rubber, epichloro rubber, or the like can be applied. Here, the holding belt 78 constitutes a rotating body according to the present invention.

  The holding belt motor 79 is configured by a stepping motor, and rotates the timing belt 80 based on a control signal output from the main body control unit 100 (see FIG. 5). Here, the holding belt motor 79 rotates the timing belt 80 while being synchronized with the belt 19 so that the rotating speed of the holding belt 78 and the rotating speed of the belt 19 are the same.

  In addition, although the gear 84g and the arm 74 were demonstrated as what was comprised separately, you may be comprised integrally.

  The sheet material conveyance assisting unit 71 configured as described above is driven by the main body control unit 100 (see FIG. 5) to drive the gear 84 g and rotate the arm 74 in the direction of the arrow 58. It is designed to swing. As a result, the sheet material conveyance assisting section 71 causes the bracket 75, the driving side holding roller 76, the driven side holding roller 77 and the holding belt 78 to pass through the arm 74, and the sheet material 6 a adsorbed to the belt 19 and the holding belt 78. Are moved between a belt contact position Pc where the belt 19 contacts and a belt separation position Pd where the sheet material 6a adsorbed to the belt 19 and the holding belt 78 are separated from each other.

  Further, the sheet material conveyance auxiliary unit 71 rotates the timing belt 80 when the holding belt motor 79 is driven by the main body control unit 100 (see FIG. 5). As a result, the sheet material conveyance auxiliary unit 71 rotates the driving side holding roller 76 via the timing belt 80 to rotate the holding belt 78 in the direction of the arrow 59.

  Next, the sheet material holding operation of the sheet feeding device 5 according to the present embodiment will be described with reference to FIGS. The flowchart shown in FIG. 15 represents the execution contents of the sheet material holding operation program executed by the main body control unit 100 using the RAM as a work area. The program for holding the sheet material is executed at predetermined time intervals when the main body control unit 100 separates and conveys the sheet material by the sheet feeding device 5.

  As shown in FIG. 15, the main body control unit 100 determines whether the position of the sheet bundle 6 stacked on the sheet material stacking unit 15 has risen, as in the first embodiment described above (step). S21).

  When the main body control unit 100 determines that the position of the sheet bundle 6 has been raised (YES in step S21), the main body control unit 100 starts the circulation of the holding belt 78 via the timing belt 80 by controlling the holding belt motor 79. (Step S22).

  Next, the main body control unit 100 controls the movement motor 84 to move the holding belt 78 to the belt contact position Pc via the arm 74 (step S23).

  Next, the main body control unit 100 determines whether or not the leading end portion of the sheet material 6a has passed the conveying rollers 65 and 66, as in the first embodiment described above (step S24).

  When the main body control unit 100 determines that the leading end portion of the sheet material 6a has passed through the conveying rollers 65 and 66 (YES in step S24), the main body control unit 100 controls the moving motor 84 to control the holding belt via the arm 74. 78 is moved to the belt separation position Pd (step S25).

  Next, the main body control unit 100 ends the rotation of the holding belt 78 by controlling the holding belt motor 79 (step S26).

  When the main body control unit 100 determines that the position of the sheet bundle 6 has not risen (NO in step S21), and when it determines that the leading end of the sheet material 6a has not passed through the conveyance rollers 65 and 66, (NO in step S24), the error display (step S27) and the error process (step S28) are performed in the same manner as the process in the first embodiment shown in steps S15 and S16 of FIG. To do.

  As described above, in the sheet feeding device 5 according to the present embodiment, since the rotating body is configured by the belt-shaped holding belt 78, the rotating body is configured by another rotating body such as a roller having a circular cross section. The nip width between the sheet material 6a adsorbed on the belt 19 and the rotating body can be increased as compared with the case where the belt 19 is present. For this reason, the sheet material 6a adsorbed to the belt 19 can be held more reliably than in the case where the rotating body is constituted by another rotating body such as a roller having a circular cross section. The sheet material can be reliably separated and fed one by one from the stacked sheet bundle 6 while suppressing the influence of environmental fluctuations and temporal fluctuations.

  Further, since the rotating body is constituted by the holding belt 78 as an elastic body, the rotating body and the belt 19 are rotated as compared with the case where the rotating body is constituted by an elastic body having a shape other than the belt such as a roller having a circular cross section. Even if the distance from the body is adjusted with low accuracy, the holding belt 78 is elastically deformed according to the pressing force of the holding belt 78 and the sheet material 6a is likely to enter between the belt 19 and the holding belt 78. Further, since the nip width between the belt 19 and the holding belt 78 is wide, the sheet material 6a adsorbed to the belt 19 can be held more effectively. Therefore, the mechanism and control contents necessary for adjusting the distance between the belt 19 and the rotating body are made simpler than in the case where the rotating body is constituted by an elastic body other than the belt. Therefore, the manufacturing cost of the sheet feeding device 5 can be further reduced.

  In the above-described embodiment, the holding belt motor 79, the drive motor 81, the paper feed tray lifting / lowering motor 83, and the moving motor 84 are described as being configured by stepping motors. You may be comprised by the brushless DC motor, the ultrasonic motor, and the direct drive motor.

  As described above, the sheet material separating and feeding apparatus and the image forming apparatus according to the present invention can reliably remove 1 from a stacked sheet bundle while suppressing the influence of environmental variation and temporal variation even in various sheet material types. It has the effect of providing a highly reliable sheet material separating and feeding apparatus and image forming apparatus capable of separating and feeding the sheet materials one by one. It is useful as a sheet material separating and feeding device that is adsorbed to and separated from an image forming apparatus, and an image forming apparatus including an electrophotographic copying machine, a facsimile machine, a printer device, and the like equipped with this sheet material separating and feeding device.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 5 Paper feeder 6a Sheet material 7 Separation part (separation conveyance part)
DESCRIPTION OF SYMBOLS 14 Electrostatic adsorption separation part 15 Sheet material stacking part 17 Drive roller 17a Drive shaft 18 Driven roller 18a Rotating shaft 19 Belt 60 Sheet conveyance part 72 Holding roller (rotating body)
73, 74 Arm 75 Bracket 76 Driving side holding roller 77 Driven side holding roller 78 Holding belt (rotating body)
79 Holding belt motor 80 Timing belt 81 Drive motor 82 Contact / separation solenoid 83 Paper feed tray lifting / lowering motor 84 Moving motor 84g Gear 91 Position detection sensor 92 Tip detection sensor (tip detection means)
100 Control unit

JP-A-9-67033 JP-A-10-95543

Claims (6)

A sheet material stacking unit for stacking a plurality of sheet materials;
It has an adsorbing member made of a dielectric and separates the uppermost sheet material from among a plurality of sheet materials stacked on the sheet material stacking portion by an adsorbing force due to an unequal electric field formed on the adsorbing member. A separation conveyance unit that adsorbs the uppermost sheet material that has been adsorbed to the adsorption member by the adsorption force and conveys the sheet material to a sheet material conveyance path,
In the sheet material separating and feeding apparatus capable of bringing the adsorbing member and the uppermost sheet material out of the stacked sheet materials into contact with and separating from each other,
The sheet material separating and feeding apparatus, wherein the separating and conveying unit includes a rotating body that can contact and separate from the uppermost sheet material adsorbed by the adsorbing member.   The sheet material separating and feeding device according to claim 1, wherein the rotating body is configured by an elastic body.   The sheet material separating and feeding device according to claim 1, wherein the rotating body is configured by a belt. A sheet conveyance unit that is further provided in the sheet material conveyance path on the downstream side in the conveyance direction of the sheet material than the separation conveyance unit, and further conveys the sheet material conveyed by the separation conveyance unit;
Provided on the downstream side in the sheet material conveyance direction in the sheet material conveyance path in the sheet material conveyance path, and provided with a leading edge detection means for detecting the leading edge of the sheet material,
The separation conveying unit separates the rotating body from the sheet material adsorbed by the adsorption member when the front end portion of the sheet material is detected by the front end detection unit. The sheet material separating and feeding device according to any one of claims 1 to 3.   The said separation conveyance part has a moving motor which moves the said rotary body between the position which contact | abuts with respect to the sheet | seat material adsorb | sucked by the said adsorption | suction member, and a separated position. The sheet | seat material separation feeding apparatus of any one of thru | or 4 thru | or 4.   An image forming apparatus comprising the sheet material separating and feeding device according to any one of claims 1 to 5.

Images