JP2009286551A - Sheet carrying device and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the scattering of paper powder generated during the maintenance of a paper powder removing means. <P>SOLUTION: To detach a powder dust removing brush 124 removing powder dust adhered on a surface of a carrying roller 117, an outer round guide member 114 is rotated to a position to/from which the powder dust removing brush 124 can be attached or detached. At that time, a bottom of the powder dust removing brush 114 is shielded with the rotated outer round guide member 114, and therefore, the paper powder scattered when the powder dust removing brush 124 can be received so as to prevent the paper powder from being scattered into a device body. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a sheet conveying apparatus that conveys a sheet, and an image forming apparatus such as a copying machine, a printer, a recorded image display apparatus, and a facsimile that forms an image.

  At present, electrophotographic image forming apparatuses are widely used in copying machines, printers, multifunction machines having copying and printer functions, facsimiles, and the like.

  In an image forming apparatus using an electrophotographic system, a visible image carried on a photosensitive member or a transfer member is transferred to a sheet as a recording material such as plain paper to obtain a recorded image. . For this reason, the sheet on which the visible image is transferred from the photosensitive member or the transfer member is conveyed to the fixing device and fixed after the visible image is fixed.

  By the way, in this type of image forming apparatus, paper dust adheres from a sheet such as paper to the guide surface and the roller peripheral surface (surface) as the usage time becomes longer. When paper dust adheres to the roller peripheral surface, the paper powder attached to the roller peripheral surface may reattach to the sheet conveyed in a lump. When the toner image is transferred to the sheet in this state, the toner image is not transferred around the portion of the sheet where the lump of paper dust adheres, and image defects such as color loss occur in the toner image on the sheet. Further, when paper dust adheres to the roller peripheral surface, the friction coefficient of the roller peripheral surface decreases, so that the sheet transport force decreases, causing a sheet transport failure.

  In order to prevent these problems, conventionally, a paper dust removing member is brought into contact with the peripheral surface of one of the conveyance rollers in the conveyance roller pair arranged so as to nip substantially the entire conveyance area of the sheet orthogonal to the sheet conveyance direction. There have been proposed those provided with a member for removing paper dust. Examples of the paper dust removing member include a brush-like member and a sheet-like member, and are arranged so as to scrape off the paper dust attached to the roller peripheral surface.

For example, as a configuration for removing paper dust adhered to the peripheral surface of the conveyance roller that conveys the sheet using the paper dust removal member, paper dust removal for removing the paper dust by pressing against the peripheral surface of the conveyance roller Some members are installed on a guide member that guides conveyance of a sheet. Then, by rotating the guide member and removing it from the apparatus main body, the paper dust removing member is taken out of the apparatus main body together so that maintenance can be easily performed (see Patent Document 1).
JP 2004-075239 A

  However, in the configuration in which the conventional paper dust removing member is installed, since the paper dust removing member is attached to the rotatable guide member, the paper adhering to the paper dust removing member due to an impact when the guide member is opened. There is a risk of powder scattering. Then, when the paper dust is scattered with the guide member opened and the paper dust adheres to the sheet conveyance area in the conveyance path, the paper dust adheres again to the sheet. For this reason, the paper dust removing member cannot remove the paper dust from the sheet, and as described above, the paper dust is left on the peripheral surface of the roller, and the sheet conveyance lump is adhered to the sheet. There was a risk of image defects on the sheet.

  The present invention has been made in view of the above problems. The object of the present invention is to disperse paper dust due to rotation of the guide member in a configuration in which the guide member is rotated to attach and detach the paper dust removal member. An object of the present invention is to provide a sheet conveying apparatus that can prevent the above.

  The present invention provides a pair of conveying rotators for conveying a sheet, a pair of guide members constituting a conveying path for guiding a sheet conveyed by the conveying rotator, and one guide member side of the pair of guide members. Detachable dust removing means for removing dust adhering to one surface of the transport rotating body arranged, and the one guide member is rotatably provided to attach and detach the dust removing means The one guide member shields the lower part of the dust removing means by the one guide member when the guide member is rotated to a position for making the dust removing means detachable.

  Since the paper dust removing means is not integrated with the guide member, the paper dust attached to the dust removing means is not scattered by an impact when the guide member is opened and closed. In addition, since the lower part of the dust removing means is shielded by the guide member when the guide member is rotated, the paper dust attached to the paper dust removing member is prevented from scattering in the apparatus main body due to the impact when the dust removing means is attached or detached. it can.

  Hereinafter, a first embodiment of the present invention will be described in detail with reference to the drawings.

  First, FIG. 8 is a schematic configuration diagram showing an example of an image forming apparatus provided with a sheet conveying apparatus to which the present invention is applied. This image forming apparatus is an electrophotographic monochrome image forming apparatus, and includes a reader unit R and a digital monochrome image printer unit P.

  The reader unit R is disposed on the upper part of the printer unit P and reads an image of a document. When reading an image of an original, the original may be placed on a platen, or a sheet-like original may be automatically and continuously used by using an automatic document feeder (ADF) (not shown). You may use the structure sent on a platen. The image signal read by the reader unit R is input to an image processing unit (not shown).

  The printer unit P is an electrophotographic image forming mechanism having an image forming unit including one drum, a developing configuration, and an intermediate transfer configuration. On an electrophotographic photosensitive drum (hereinafter referred to as a photosensitive drum) 1 as an image carrier, a laser beam is irradiated by a laser scanner 2 to form an exposure image. The exposure image formed on the photosensitive drum 1 is developed with a toner image by a developing device. The toner image on the photosensitive drum 1 is further primarily transferred onto the intermediate transfer belt 5 to form an unfixed toner image on the intermediate transfer belt 5. Thereafter, the toner image is secondarily transferred onto a sheet as a recording material and then fixed to output a black and white image formed product.

  This image forming unit will be described in more detail. In FIG. 8, the photosensitive drum 1 is rotationally driven in a counterclockwise direction indicated by an arrow at a predetermined speed, and its peripheral surface is uniformly charged to a predetermined polarity and potential by a charging means. The charged surface is irradiated with a laser beam by a laser scanner 2 serving as an exposure unit and subjected to scanning exposure.

  The laser scanner 2 includes a laser output unit, a polygon mirror, an imaging lens, a folding mirror, and the like. The laser scanner 2 outputs a laser beam modulated in accordance with an image information signal input from the image processing unit. The exposed surface is subjected to scanning exposure. As a result, an electrostatic latent image corresponding to the scanning exposure pattern is formed on the surface of the photosensitive drum 1.

  In addition to the image information read from the reader unit R, the image information signal may be synthesized and formed from image information transmitted from an external device such as a personal computer. The electrostatic latent image formed on the photosensitive drum 1 is developed as a toner image by a developing device.

  The intermediate transfer belt 5 is an endless belt made of a dielectric material having flexibility. The intermediate transfer belt 5 is in contact with the photosensitive drum 1, and the contacted portion is the primary transfer nip portion T1. Then, a toner image is formed on the photosensitive drum 1 by the above-described image forming process of charging, exposure, and development, and the toner image is transferred onto the intermediate transfer belt 5 at the primary transfer nip T1.

  On the other hand, the sheet feeding roller 11 of the sheet feeding cassette 81 is driven at a predetermined control timing, the sheets S stored in the sheet feeding cassette 81 are separated and sent out one by one, and are conveyed from the conveyance path 13 to the registration unit 14. Sent. In the registration unit 14, the conveyance start timing of the stopped sheet S is controlled in order to correct the skew of the sheet S and perform secondary transfer by matching the toner image on the intermediate transfer belt 5 and the sheet.

  A secondary transfer roller 15 is a pressure control mechanism (not shown) in a first state in which the secondary transfer roller 15 is in a predetermined pressure contact with the intermediate transfer belt 5 and in a second state separated from the outer surface of the intermediate transfer belt 5. It is switched by. The secondary transfer roller 15 is switched and held in a second state separated from the outer surface of the intermediate transfer belt 5. Then, the secondary transfer nip portion T <b> 2 is formed between the outer peripheral surface of the intermediate transfer belt 5 by switching to the first state in order to transfer the toner image.

  The sheet S conveyed from the registration unit 14 is nipped and conveyed through the secondary transfer nip T2, and an unfixed toner image on the intermediate transfer belt 5 is applied by a predetermined secondary transfer voltage applied to the secondary transfer roller 15. Is transferred to the sheet S.

  The sheet S exiting the secondary transfer nip T2 is separated from the surface of the intermediate transfer belt 5 and conveyed to the fixing device 18 by the conveyance belt 17. In the fixing device 18, the unfixed toner image on the sheet S is fused on the sheet S by heat and pressure to form a fixed image. When the sheet S exiting the fixing device 18 is discharged with the image surface facing upward, it is discharged from the discharge portion 23 through the conveyance path 19. In addition, when the sheet S is discharged with the image surface facing downward, the sheet S is conveyed to the upstream path 20, subsequently switched back in the reverse path 21, and discharged from the discharge unit 23 through the downstream path 22.

  Reference numeral 24 denotes a re-conveying path for sending the sheet reversed in the reversing path 21 to the secondary transfer nip T2 in order to form an image again in the image forming unit when image images are formed on both sides of the sheet. It is.

  Here, the sheet conveying apparatus (conveying path 13) to which the present invention is applied will be described.

  1 and 3 are schematic configuration diagrams of a sheet conveying apparatus to which the present invention is applied. 2 and 4 are schematic sectional views of a sheet conveying apparatus to which the present invention is applied. 1 and 2 show a state in which the conveyance path of the R guide unit 112 is closed and a sheet can be conveyed, and FIGS. 3 and 4 show a state in which the conveyance path of the R guide unit 112 is open.

  The sheet fed from the paper feed cassette 81 by the paper feed roller 11 is conveyed to the R guide portion 112 through the upstream guide portion 111. The R guide portion 112 includes a pair of guide members, an outer R guide member 114 and an inner R guide member 115, and a pair of transport rollers as a pair of transport rotators configured by a transport roller 117 and a driven roller 118.

  The conveying roller 117 is supported on the outer R guide member 114 side by bearings 120 (only the front side is shown) attached to the front and rear frames of the apparatus main body (not shown), and the sheet is moved downstream by the rotational drive of a driving motor (not shown). Rotate in the transport direction. Then, when the conveying roller 117 rotates, the sheet is nipped by the driven roller 118, guided along the R guide portion 112, and conveyed toward the image forming portion.

  The driven roller 118 is rotatably supported by a bearing 122 movably attached to a driven roller support 121 provided on the inner R guide member 115 side. When the bearing 122 is urged toward the transport roller 117 by the compression spring 123, the driven roller 118 is pressed against the transport roller 117. As a result, the sheet sandwiched between the conveying roller pairs 117 and 118 of the R guide unit 112 is conveyed to the upper downstream guide unit 113 by the rotation of the conveying roller 117.

  Here, the configuration of the dust removing means provided in the R guide portion 112 will be described in detail.

  The conveyance roller 117 and the driven roller 118 form a nip portion in substantially the entire region (full width) of the sheet conveyance region in a direction orthogonal to the sheet conveyance direction. Then, paper dust or dust adhering to the sheet surface can be removed by adhering to the peripheral surface of the transport roller 117. A paper dust removing brush 124 is in contact with the peripheral surface of the conveying roller 117 on the opposite side of the sheet conveying area of the outer R guide member 114, and paper dust or dust attached to the conveying roller 117 is removed by the paper dust removing brush 124. To do. The paper dust removing brush 124 is supported by a paper dust removing brush base 125 as a support member, and the paper dust removing brush base 125 is detachably attached to a brush base stay 126 provided in the apparatus main body. Maintenance of the paper dust removing brush 124 is performed by removing the paper dust removing brush base 125 from the brush base stay 126. Since the paper dust removing brush 124 and the paper dust removing brush base 125 constituting the dust removing means are unitized in this way, the paper dust removing means can be easily attached and detached, and the paper dust removing brush 124 is removed from the taken-out unit. Clean or replace.

  A dust container 127 is provided in the upstream guide portion 111 located below the installation position of the paper dust removing brush 124, and the paper dust and dust removed from the transport roller 117 by the paper dust removing brush 124 are removed from the paper dust. It falls downward from the brush 124 and is stored in the dust container 127.

  One outer R guide member 114 of the guide member is rotatably supported by the bearing 120 of the conveying roller 117, and is fixed to the apparatus main body by a fixing member 131 when the sheet is conveyed.

  The other inner R guide member 115 of the guide member is rotatably supported by a rotating shaft 128 provided on the front side and the rear side of the apparatus main body below the inner R guide member 115. The inner R guide member 115 is fixed to the apparatus main body by a magnet catch 130 by a magnet receiver 129 provided on the inner R guide member 115, whereby the inner R guide member 115 is closed and a conveyance path through which a sheet can be conveyed is provided. Constitute. In this embodiment, the holding means for holding the inner R guide member 115 in the closed state is configured by the magnet catch 130 and the magnet receiver 129. For example, the inner R guide member 115 is screwed to the frame of the apparatus main body. May be fastened.

  When the conveyance path capable of guiding the sheet is opened, the inner R guide member 115 is rotated from the guide position to the open position with the rotation shaft 128 as the rotation center, thereby moving away from the outer R guide member 114. At the same time, the driven roller 118 is also separated from the conveying roller 117.

  When performing maintenance such as cleaning or replacement of the paper dust removing brush 124, the outer R guide member 114 is rotated in the same direction after the inner R guide member 115 is rotated in the direction in which the conveyance path is opened. As a result, the paper dust removing brush 124 can be accessed from between the downstream guide portion 113 and the outer R guide member 114. Then, the paper dust removing brush base 125 is removed from the brush base stay 126, and the paper dust removing brush 124 is cleaned or replaced.

  The outer R guide lower end portion 135 is bent, and when the outer R guide member 114 rotates to open the conveyance path, the outer R guide lower end portion 135 is more horizontally positioned than the paper dust removing brush 124 in the horizontal direction. It extends in the opposite direction. Due to this configuration, the outer R guide member 114 shields the lower part of the paper dust removing brush 124. Thereby, it is possible to prevent paper dust and dust attached to the paper dust removing brush 124 from being scattered downward due to an impact when an operation of removing the paper dust removing brush stand 125 from the brush stand stay 126 is performed. Further, since the outer R guide member 114 and the brush base stay 126 are in contact with each other when the outer R guide member 114 rotates, the lower portion of the paper dust removing brush 124 can be sealed. Therefore, it is more effective in preventing scattering of paper dust due to impact on the paper dust removing brush 124 during maintenance.

  Then, the paper dust and dust collected near the lower end portion 135 of the outer R guide fall downward by closing the outer R guide member 114 and are stored in the dust storage portion 127.

  In addition, when the outer R guide member 114 rotates, the outer R guide lower end portion 135 is configured to be positioned on the outer side (opposite side of the conveying path) of the brush base stay 126, and the outer R guide lower end portion 135 is further configured. It is formed by bending upward. With this configuration, even when a gap is formed between the outer R guide member 114 and the brush base stay 126, the configuration of the end portion of the outer R guide lower end portion 135 can suppress the scattering of paper dust.

  In addition, a shielding member 132 that covers the upper portion of the transport roller 117 is provided above the transport roller 117 of the outer R guide member 114 when the outer R guide member 114 is closed. As the outer R guide member 114 rotates, the shielding member 132 shields the scattering of paper powder in the substantially horizontal direction (the direction along the back surface of the outer R guide member 114). As a result, it is possible to prevent paper dust attached to the paper dust removing brush 124 from being scattered in the direction of the inner R guide member 115 due to the impact of attaching and detaching the paper dust removing brush 124.

  Thereby, it is possible to prevent sheet conveyance failure and image failure due to the paper dust of the removed sheet being scattered and adhering to the sheet again. Further, a conveying roller 117 is used as a roller for removing the paper dust on the sheet, and the conveying roller 117 is disposed at a position where the image forming unit slides on the surface on which the image of the sheet is formed to remove the paper dust. Therefore, it is possible to effectively prevent image defects.

  Further, since the shielding member 132 is extended above the paper dust removing brush 124 when the guide members 114 and 115 are closed, the paper dust removing brush 124 can be accessed unless the outer R guide member 114 is rotated. It can not be attached and detached. As a result, it is possible to prevent the paper dust removing brush 124 from being accidentally removed, or to prevent the paper dust removing brush 124 from coming into contact with the conveying roller 117 at a predetermined position.

  As described above, the space below the paper dust removal brush 124 and the open / close side is shielded in accordance with the rotation of the outer R guide member 114, so that the paper dust attached to the paper dust removal brush 124 due to a shock at the time of rotation is obtained. It is possible to prevent scattering downward. Thereby, it becomes possible to reduce unnecessary work such as cleaning the paper dust scattered in the apparatus main body.

  In the first embodiment, the paper dust removing brush is used as a means for removing the paper dust adhered to the conveying roller 117. However, a sheet-like member or foamed polyurethane that scrapes the paper dust on the surface by the rotation of the conveying roller. It may be a blade, felt or the like. Further, the bearing 120 that supports the transport roller 117 is used as the rotation center of the outer R guide member 114. However, the rotation roller shaft is provided with a bearing for the rotation center of the outer R guide member, or the transport roller shaft itself. May be used as the rotation center of the outer R guide member 114.

  Next, a second embodiment according to the present invention will be described. The second embodiment differs from the sheet conveying apparatus described in the first embodiment in that the rotation center of the guide member is positioned below the conveying roller shaft. It should be noted that portions different from the first embodiment will be described, and other configurations are the same as those of the first embodiment, and thus detailed description thereof will be omitted.

  FIG. 5 is a cross-sectional view showing a state in which the inner R guide member 115 and the outer R guide member 114 are closed when the rotation center of the outer R guide member 114 is positioned below the conveying roller 117. FIG. 6 is a cross-sectional view showing a state in which the inner R guide member 115 and the outer R guide member 114 are rotated when the rotation center of the outer R guide member 114 is positioned below the conveying roller 117.

  A rotation center shaft 133 of the outer R guide member 114 is provided below the transport roller 117 with respect to the front and rear frames of the apparatus main body (not shown). Even if the rotation center of the outer R guide member is positioned below the transport roller 117, the rotation of the outer R guide member 114 is not limited by the most downstream portion 134 of the upstream guide portion 111. It is possible to shield the lower portion with the outer R guide lower end portion 135. For this reason, even when the rotation center of the outer R guide member 114 is positioned below the conveying roller shaft, it is possible to prevent the scattering of paper dust and dust attached to the paper dust removing brush 124 during maintenance.

It is the schematic of the sheet conveying apparatus which concerns on embodiment of this invention. It is sectional drawing of the sheet conveyance which concerns on embodiment of this invention. It is a schematic diagram of sheet conveyance concerning an embodiment of the present invention. It is sectional drawing of the sheet conveyance which concerns on embodiment of this invention. It is sectional drawing of the sheet conveyance which concerns on embodiment of this invention. It is sectional drawing of the sheet conveyance which concerns on embodiment of this invention. 1 is a cross-sectional view of an image forming apparatus according to an embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 111 Upstream guide part 112 R guide part 113 Downstream guide part 114 Outer R guide member 115 Inner R guide member 117 Conveyance roller 118 Follower roller 120 Bearing 121 Follower roller support part 122 Bearing 123 Compression spring 124 Paper dust removal brush 125 Paper dust removal brush Stand 126 Brush stand stay 127 Dust container 128 Rotating shaft 129 Magnet receiver 130 Magnet catch 131 Fixing member 132 Shielding member 133 Rotating center shaft 134 Upstream guide portion most downstream portion 135 Outer R guide lower end portion

Claims (10)

A pair of conveying rotators for conveying the sheet;
A pair of guide members constituting a conveyance path for guiding a sheet conveyed by the conveyance rotation body;
Removable dust removing means for removing dust adhering to one surface of the transport rotating body arranged on one guide member side of the pair of guide members,
Have
The one guide member is rotatably provided to attach and detach the dust removing means, and the one guide member is rotated when the one guide member is rotated to a position for making the dust removing means attachable and detachable. A sheet conveying apparatus characterized in that a lower portion of the dust removing means is shielded by a guide member.   The sheet conveying apparatus according to claim 1, wherein the one guide member is supported so as to be rotatable about a shaft of the one conveying rotating body or the bearing.   The other guide member of the pair of guide members is rotatably provided from a guide position capable of guiding a sheet to an open position that opens the transport path, and the other transport rotator of the transport rotator is The sheet conveying apparatus according to claim 1, wherein the sheet conveying apparatus moves with the rotation of the other guide member.   The dust removing means is supported by a support member supported by the apparatus main body, and the dust removing means is brought into contact with the support member when the one guide member rotates to a position where the dust removing means can be attached or detached. The sheet conveying apparatus according to any one of claims 1 to 3, wherein a lower portion of the means is shielded.   The dust removing means is supported by a support member supported by the apparatus main body, and when the one guide member is rotated to a position where the dust removing means can be attached or detached, the end of the one guide member is supported by the support member. 4. The apparatus according to claim 1, wherein the guide member is positioned in a direction opposite to the sheet conveyance path in a horizontal direction with respect to the member, and an end portion of the one guide member is bent upward. 5. The sheet conveying apparatus according to 1.   The one guide member includes a shielding member, and the shielding member shields the dust removing means when the one guide member is rotated to a position for making the dust removing means removable. The sheet conveying apparatus according to any one of claims 1 to 5.   The sheet conveying apparatus according to claim 6, wherein when the one guide member constitutes a conveying path, the shielding member blocks an upper portion of the paper dust removing member.   The sheet conveying apparatus according to any one of claims 1 to 7, further comprising a dust container below a position where the dust removing unit is installed. The sheet conveying apparatus according to any one of claims 1 to 8,
An image forming unit that forms an image on a sheet conveyed by the sheet conveying device;
An image forming apparatus comprising:   10. The image forming apparatus according to claim 9, wherein the dust removing unit removes dust attached to a surface of a conveyance rotating body that is in sliding contact with a side on which an image is formed by the image forming unit of the sheet.

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