JP2007119096A - Unit of image forming device, image forming device and automatic paper feeding device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a unit of an image forming device giving little load to rotation action of a roller and generating no non-contact by deviation in a thrust direction of a rotation roller. <P>SOLUTION: The unit of the image forming device is provided with a plurality of rotation rollers; conductive bearings for the respective rotation rollers; and a metal plate mounted between the plurality of conductive bearings and a surface of a box body. A flat spring part is erected on the metal plate in an approximately thrust direction is abutted on outer peripheral surfaces of the respective bearings to perform removal of electricity of the rotation roller. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a technique for grounding a rotating roller of a unit disposed in an image forming apparatus such as a printer, a copier, or a multifunction peripheral, or an automatic paper feeder.

  2. Description of the Related Art In recent years, image forming apparatuses such as printers, copiers, and multifunction machines have become widespread not only in offices but also in general households. These image forming apparatuses are provided with a number of rotating rollers such as a conveyance roller for conveying the printing paper, an agitation roller for agitating the toner, and a fixing roller for fixing the toner to the printing paper. ing.

  For example, let's take a look at an automatic document feeder (ADF). FIG. 4 is an internal structure diagram of an example of the automatic paper feeder 400. Documents placed on the document tray 408 are separated one by one by the pickup roller 401, the feeding belt 402, and the separation roller 403, and are fed into the automatic sheet feeder 400. The fed original is conveyed to an image reading position by a registration roller 404 and a conveyance roller 405. At the image reading position, an original is read by an image reading means 410 such as a CCD (Charge Coupled Device), and is discharged onto a discharge tray 409 by an intermediate roller 406 and a discharge roller 407.

  By the way, static electricity is generated in a rotating roller in the image forming apparatus such as each roller of the automatic sheet feeder 400 due to friction caused by the rotation. This static electricity causes a malfunction of the machine and a defective image.

In order to remove the static electricity, the rotating roller may be grounded (grounded) by some method. For example, Patent Document 1 discloses a technique for grounding a rotating roller. In Patent Document 1, conductive bearings such as a rotating shaft of a separation roller and an intermediate shaft for transmitting driving force are used in a sheet feeding device, and a metal plate is sandwiched between these bearings and the case surface. By connecting the metal plate to the ground, each shaft is grounded via the metal plate and the conductive bearing.
JP 2003-95463 A (page 4, FIG. 3)

  However, such a conventional configuration may cause a grounding failure. In order to suppress the load applied to the rotating roller, a gap is usually provided in the thrust direction. When the rotating roller is driven, the roller moves in the thrust direction through this gap. Since the roller and the metal plate are separated or contacted by the movement, it is not possible to sufficiently neutralize the charge. If the gap in the thrust direction is overfilled or restricted, the load on the rotating roller will increase.

  The present invention has been made in view of such problems, and provides a unit of an image forming apparatus, an image forming apparatus, and an automatic paper feeding apparatus that can perform static elimination of a roller without applying a load to the roller. With the goal.

  In order to achieve the above object, the present invention employs the following means.

  First, conductive bearings are used for the bearings of the plurality of rotating rollers, respectively, and a metal plate is attached between the surface of the casing of the unit and the plurality of conductive bearings.

  And the leaf | plate spring part erected in the substantially thrust direction with the said metal plate is made to contact | abut to the outer peripheral surface of each bearing. Since the leaf spring portion is erected substantially in the thrust direction, the contact state can be maintained even if the roller moves in the thrust direction. Moreover, since the said leaf | plate spring part is arrange | positioned along the moving direction of a roller, the movement of a roller is not controlled more than necessary. For this reason, by grounding the metal plate, the roller can be neutralized without applying a load to the roller. Moreover, a complicated structure is not required.

  According to the present invention, the use of a single metal plate is simple in structure, and the leaf spring portion comes into contact with the outer peripheral surface of the bearing, so that non-contact due to the displacement of the rotating roller in the thrust direction does not occur. It is possible to achieve the effect of eliminating the charge of the roller without applying a load to the roller.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a diagram for explaining the overall configuration of a copying machine to which the present invention is applied. The copying machine 101 includes an image reading unit 102 and an image forming unit 103. The image reading unit 102 reads an image of a document and generates digital data of the image. The image reading unit 102 has a document table 104 such as contact glass on the top surface of the housing. The document can be placed on the document table 104. A scanning optical system 105 is disposed below the document table 104. The scanning optical system 105 includes a first carriage 106, a second carriage 107, and a condenser lens 108. The first carriage 106 is provided with a linear light source 109 and a mirror 110, and the second carriage 107 is provided with mirrors 111 and 112. A light source 109 illuminates the document. The mirrors 110 to 112 guide the reflected light from the document to the lens 108, and the lens 108 forms an image of the light on the light receiving surface of the line image sensor 113. In the scanning optical system 105, the first carriage 106 and the second carriage 107 are provided so as to be reciprocable in the sub-scanning direction 114. By moving the first carriage 106 and the second carriage 107 in the sub-scanning direction 114, the image of the document placed on the document table 104 can be read by the image sensor 113. The image sensor 113 generates document image data from the light image incident on the light receiving surface.

  The image forming unit 103 prints image data obtained by the image reading unit 102 or image data received from another device via a network on a sheet. The image forming unit 103 is provided with a photosensitive drum 115. The photosensitive drum 115 rotates in the arrow direction 116 at a constant speed. Around the photosensitive drum 116, a charger 117, an exposure device 118, a developing device 119, a transfer device 120, and the like are arranged in this order from the upstream side in the rotation direction. The charger 117 uniformly charges the surface of the photosensitive drum 115. The exposure device 118 irradiates light on the surface of the uniformly charged photoreceptor drum 115 according to the image data of each color, thereby forming an electrostatic latent image on the photoreceptor drum 115. The developing device 119 attaches toner of each color to the electrostatic latent image and forms a toner image on the photosensitive drum 115. The transfer device 120 transfers the toner image on the photosensitive drum 115 to a sheet.

  The image forming unit 103 feeds paper from the manual feed tray 121, the paper feed cassettes 122 and 123, and the like to the transfer unit between the photosensitive drum 115 and the transfer device 120. Various sizes of paper can be placed on or stored in the manual feed tray 121 and the cassettes 122 and 123. The image forming unit 103 selects a sheet specified by the user or a sheet corresponding to the automatically detected document size, and pulls out the selected sheet from the tray 121 and the cassettes 122 and 123 by the feeding roller 124. The drawn paper is sent to the transfer unit by the transport roller 125 and the registration roller 126. The sheet on which the toner image is transferred is conveyed to the fixing device 127. The fixing device 127 has a fixing roller 128 and a pressure roller 129, and fixes the toner image on the paper by heat and pressing force. The image forming unit 103 discharges the sheet that has passed through the fixing device 127 to the discharge tray 130 or 131. Which of the paper discharge trays 130 and 131 is discharged is controlled by the switching claw 132, and the paper is discharged to one paper discharge tray by the discharge rollers 133 or 134.

  In such a copier 101, an automatic paper feeder 400 as already described in the background art is attached so as to be openable and closable. The user places a document on the document table 104 or sets the document on the automatic paper feeder 400. The automatic paper feeder 400 feeds the originals set on the original tray 408 to the conveyance path 411 one by one. There is an image reading position 135 on the conveyance path 411. On the upper surface of the casing of the image reading unit 102, not only the document table 104 but also a reading glass 136 for the image reading position 135 is provided. When reading an image of a document set on the automatic paper feeder 400, the image reading unit 102 temporarily fixes the first carriage 106 and the second carriage 107 to the image reading position 135. When the document passes through the image reading position 135, the document is illuminated through the reading glass 136, and the image of the document is read. The document that has passed the image reading position 135 is discharged to a discharge tray 409.

  FIG. 2 is a perspective view of an intermediate transport unit of the automatic paper feeder. Inside the automatic paper feeder 400, an intermediate transport unit 412 is provided. In the intermediate conveyance unit 412, a separation roller 403, a registration roller 404, a conveyance roller 405, and an intermediate roller 406 are disposed. The intermediate transport unit 412 also includes a document reading unit 413 that is disposed between the transport roller 405 and the discharge roller 407 on the main body side and reads a document surface different from the surface read at the image reading position 135.

  Conductive bearings 418 to 420 for the rotation shaft 415 of the registration roller 404, the rotation shaft 416 of the conveyance roller 405, and the rotation shaft 417 of the intermediate roller 406 are disposed on the side surface 414 of the intermediate conveyance unit 412.

  The casing of the intermediate transport unit 412 is made of resin, and a metal plate 421 is attached to the side surface 414 of the intermediate transport unit 412 in order to remove electricity from each roller. Each roller is neutralized by grounding the metal plate 421. The metal plate 421 is sandwiched between the plurality of conductive bearings 418 to 420 and the side surface 414 of the intermediate transport unit 412.

  FIG. 3 is a perspective view of a metal plate. The metal plate 421 is provided with an opening 301, a notch 302, and an opening 303 for fitting the bearings 418 to 420 of the registration roller 404, the transport roller 405, and the intermediate roller 406 (indicated by an arrow A3). Fit in the direction). Note that the metal plate 421 is brought into contact with the three bearings 418 to 420 in the automatic paper feeder of the image forming apparatus to which the present invention is applied. In carrying out the present invention, openings and notches are provided according to the number and positions of rotating rollers that need to be grounded. For the sake of simplicity, these three rotating rollers 404 to 406 are specified below. I will explain it.

  As shown in FIG. 3, leaf springs 304 to 306 are provided in the openings and notches 301 to 303, respectively. These plate spring portions 304 to 306 are bent substantially in parallel with the direction A3 in which the bearings 418 to 420 are fitted, that is, in the thrust direction, so as to have the function of the leaf springs, and contact the outer peripheral surfaces of the three bearings 418 to 420 It comes to touch.

  The feature of the present invention is that the leaf springs 304 to 306 are brought into contact with the side surfaces of the bearings 418 to 420 in this way, and according to this, non-contact due to the displacement of the rotating roller in the thrust direction does not occur. Even if the displacement occurs, the leaf springs 304 to 306 and the bearings 418 to 420 contact at different positions in the thrust direction.

  5 and 6 are perspective views showing the relationship between the leaf spring portion and the bearing. In this figure, the bearings 418 and 419 are displayed in a floating state without being fitted into the opening 301 and the notch 302. As shown in FIG. 5, the leaf spring portion 304 is bent substantially in the thrust direction, and when the bearing 418 is fitted into the opening 301, it abuts on the outer peripheral surface 501 of the bearing 418 parallel to the thrust direction. In a state where the bearing 418 is fitted, a stress is applied to the leaf spring portion 304 and the elastic deformation is slightly caused. This realizes the function as a leaf spring. Similarly, the leaf spring portion 305 contacts the outer peripheral surface 502 of the bearing 419. Even if a shift occurs in the thrust direction, the leaf spring portion extends in the thrust direction, so that the contact state is maintained.

  By adopting such a structure, if the metal plate 412 is grounded, each rotating roller can be neutralized via the leaf springs 304 to 306 and the conductive bearings 418 to 420 even if there is a shift in the thrust direction. Can do it. Further, since the leaf springs 304 to 306 are formed along the moving direction of the rotating roller, the moving of the rotating roller in the thrust direction is not hindered more than necessary. Therefore, it is possible to remove static electricity without applying an extra load to the rotating roller.

  Particularly in this embodiment, as shown in FIGS. 3, 5 and 6, since two leaf springs are formed for one bearing, it can be maintained in a more reliable contact state. Further, the load applied by the two leaf springs to the rotating roller is not large. In addition, the number of the leaf | plate spring part with respect to one bearing may be one, and may be three or more.

  Also, if the leaf spring part is applied to the surface along the radial direction of the bearing, the leaf spring part may be plastically deformed due to repeated movement of the rotating roller in the thrust direction, and the elasticity may be lost. If the leaf spring portion is provided along the direction, plastic deformation of the leaf spring portion due to repeated stress can be prevented.

In addition, a plurality of rollers can be grounded by a single member of the metal plate 421, and it is not necessary to employ a complicated structure for neutralizing the rollers.
In the above description, the automatic paper feeder of the copying machine has been described as an example. However, the present invention can be applied to other image forming apparatuses such as a printer, a facsimile machine, and a multifunction peripheral. It is also possible to apply to other units.

  The unit of the image forming apparatus and the automatic paper feeder according to the present invention are simple in structure by adopting a single metal plate, and the leaf spring joined to the metal plate comes into contact with the side surface of the rotating roller. Since non-contact due to the displacement of the rotation roller in the direction of the rotation axis does not occur, the rotation roller can be reliably grounded at all times. Therefore, it is useful for a printer, a copying machine, a multi-function machine, etc., and their document feeders in order to neutralize the built-in rotating roller.

1 is a diagram illustrating an overall configuration of a copying machine to which the present invention is applied. The perspective view of the intermediate conveyance unit of an automatic paper feeder. The perspective view of a metal plate. The internal structure figure of an automatic paper feeder. The perspective view which shows the relationship between a leaf | plate spring part and a bearing. Another perspective view showing the relation between a leaf spring part and a bearing.

Explanation of symbols

101 copier
400 Automatic paper feeder
404 registration rollers
405 Transport roller
406 Intermediate roller
412 Intermediate transfer unit
413 Document reader
414 Side of intermediate transfer unit
415, 416, 417 rotation axis
418, 419, 420 Conductive bearing
421 Metal plate
301, 303 opening
302 Notch
304, 305, 306 Leaf spring
501 and 502 Outer surface

Claims (4)

In a unit attached to an image forming apparatus,
A plurality of rotating rollers;
A conductive bearing for each rotating roller;
A metal plate attached between the plurality of conductive bearings and the housing surface;
A unit of an image forming apparatus, characterized in that the metal plate has a leaf spring portion that is erected substantially in the thrust direction and abuts against the outer peripheral surface of each bearing.   The unit of an image forming apparatus according to claim 1, wherein the casing is made of resin.   An image forming apparatus comprising the unit according to claim 1. A separation roller, a registration roller, a conveyance roller for conveying a document from the registration roller to an image reading position, and a document surface that is disposed between the conveyance roller and the discharge roller and is different from the surface read at the image reading position. An intermediate conveyance unit having an intermediate roller disposed between the original reading unit and the discharge roller;
Conductive bearings of the registration roller, the transport roller, and the intermediate roller disposed on the side surface of the unit,
A metal plate attached to the side surface of the unit in a state of being sandwiched between the conductive bearings of the registration roller, the transport roller and the intermediate roller and the side surface of the unit;
An automatic paper feeder, wherein the metal plate has a leaf spring portion that is provided substantially in a thrust direction and abuts against an outer peripheral surface of each bearing.

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