JP3894172B2 - Paper transport device - Google Patents

Description

  The present invention relates to a paper conveying apparatus for conveying an original to an image reading unit in a scanner, a facsimile, a copying machine, or the like.

  Some scanners, facsimiles, copiers, and the like are equipped with a paper transport device such as an auto document feeder (hereinafter referred to as “ADF”) that sequentially feeds a plurality of documents. According to this, a plurality of documents placed on the document tray can be continuously and automatically conveyed to the image reading surface.

  FIG. 10 is a schematic perspective view showing the external appearance of a copy / facsimile multifunction peripheral 900 equipped with an ADF. As shown in FIG. 10, the copy / facsimile multifunction peripheral 900 has a platen glass on which a document to be read is placed. An installed reading table 901, a document pressing cover 902 that presses and fixes the document on the platen glass, an operation panel 903 for inputting reading start of the document, and an image for recording an image on a recording sheet A main body 904 including a recording unit, a transmission unit for transmitting images, and the like, and a paper feed cassette 905 for supplying recording paper for recording the read image are provided. In the copy / facsimile multifunction peripheral 900, a paper transport device is configured by the ADF in the document pressing cover 902, and the document on the document tray 906 is disposed below the document tray 906 by the ADF. The image is read by the image reading means such as a CCD provided in the reading table 901 when passing through the image reading surface during the transfer process. It has come to be.

  In the conventional paper transport device, the transport path from the document tray 906 through the image reading surface to the paper discharge tray 907 includes a laterally U-shaped outer guide surface and an inner guide surface, and the outer guide surface is For example, it is formed by the housing of the document pressing cover 902, and the inner guide surface is formed by a paper guide disposed in the document pressing cover 902. In such a conventional paper transport device, the paper is transported while sliding along the transport path with the inner guide surface or the outer guide surface, and static electricity is generated by friction between the paper and the inner guide surface or the outer guide surface. When the sheet is charged and the sheet being conveyed comes into close contact with the paper guide or the like, there is a problem that the skew of the sheet and the conveyance speed become unstable, and the image quality of the read image deteriorates. In particular, when a paper guide, a housing, or the like is made of a resin, the problem of charging due to static electricity becomes more prominent. On the other hand, a configuration has been devised in which static electricity due to friction is released through the guide plate by using an outer guide surface on which the paper slides strongly as a guide plate made of a conductive member (see Patent Document 1).

JP 2001-31277 A

  Scanners, facsimiles, copiers, etc. are desired to be smaller and lighter and cost-reduced, and the paper transport devices equipped in these are also desired to be smaller and lighter and cost-reduced. Even in the case of assembling different types of materials such as synthetic resin and conductive members as in the paper transport apparatus, it is necessary to reduce the number of parts and simplify the assembly process. From the viewpoint of resource recycling, etc., each part of the paper transport device must be disassembled and reused or discarded for each type of material such as metal and plastic. It is desirable to simplify the dismantling work at the time of disposal. Further, in order to prevent paper jams and maintenance in the paper transport device, a cover is provided on the housing and the paper guard can be swung. However, it is necessary to consider the ease of such maintenance work.

  In addition, when a paper conveyance device is provided in the document pressing cover 902 provided so as to be openable and closable with respect to the reading table 901 having an image reading surface, the document pressing cover 902 is used to perform image reading using the paper conveyance device. However, the position of the document holding cover 902 in the closed state differs slightly every time it is opened and closed. For example, when the sheet conveying device is used in a state where the document pressing cover 902 is not completely closed but slightly lifted from the document reading surface. For this reason, if the passing position of the original reading surface varies, the read image quality may deteriorate.

  The present invention has been made to solve such problems, and an object of the present invention is to provide a paper transport device that can be reduced in size and weight, can be reduced in cost, and can be easily disassembled and maintained during disposal. To do. Another object of the present invention is to maintain a document passage position relative to the document reading surface in a paper transporting device provided in a document pressing cover that can be opened and closed with respect to a reading table having an image reading surface. It aims to provide a means that can be maintained.

  The present invention is equipped with a document presser cover which is provided so as to be openable and closable with respect to a reading table having an image reading surface, and passes a sheet on a document tray through a horizontally U-shaped conveyance path via the image reading surface. A side frame having a paper guide main body constituting an inner guide surface of a laterally U-shaped conveyance path and a roller shaft bearing of a roller disposed in the conveyance path for conveying a sheet in a paper conveyance device for conveying to a paper discharge tray Are integrally formed of a plastic material, and a static elimination guide made of a conductive member constituting an inner guide surface downstream of the laterally U-shaped folded portion is vertically moved with respect to the image reading surface on the side frame. It is provided so as to be swingable as possible, and a positioning member is interposed between the inner guide surface of the static elimination guide and the image reading surface, and the static elimination guide is moved downward with respect to the image reading surface. Biasing member is provided to energize, wherein the ground member for grounding the roller shaft and the charge elimination guide to the side frame is provided.

  Further, according to the present invention, the grounding member is fixed so that a semicircular protrusion is formed on the band plate material, and the semicircular protrusion is spring elastic in the swing axis direction of the static elimination guide, The neutralization guide is provided with a contact wall orthogonal to the swing axis, and when the neutralization guide swings, the edge of the contact wall comes into contact with the curved surface of the semicircular protrusion, and the semicircular protrusion By elastically moving the contact wall, the wall surface of the contact wall and the curved surface of the semicircular protrusion are brought into pressure contact with each other.

  According to the present invention, the number of parts and the number of assembling steps are reduced, and the disassembling work and the maintenance work at the time of recycling are simplified, so that a small and low cost and high workability paper transport apparatus can be realized. In addition, static electricity generated by the friction between the paper guide body and the paper can be removed by the static elimination guide. By providing the static elimination guide on the downstream side of the transport path, static electricity caused by friction with the paper guide body can be efficiently removed. Can be removed. Further, the neutralization guide is urged in a direction that can move up and down with respect to the image reading surface, and the positioning member positions the inner guide surface of the neutralization guide and the image reading surface. Even when a gap is generated when the presser cover is opened and closed, the sheet passing position with respect to the image reading surface can be kept constant.

  Further, according to the present invention, when the static elimination guide swings, the edge of the contact wall comes into contact with the curved surface of the semicircular protrusion and elastically moves the semicircular protrusion. By swinging the static elimination guide, the wall surface of the contact wall and the curved surface of the semicircular protrusion can be securely brought into contact with each other without crushing the semicircular protrusion.

  FIG. 1 is a diagram showing an external appearance of an upper part of a copy / facsimile multifunction peripheral 100 including a paper transport device 1 according to an embodiment of the present invention. As shown in the figure, the copy / facsimile multifunction peripheral 100 is configured to press and fix the original on the platen glass 10 with the reading table 101 on which the platen glass 10 on which the original to be read is placed is arranged. And a document presser cover 102 that can be opened and closed with respect to the reading table 101. A sheet conveying apparatus 1 described in detail below is disposed as an ADF in the document pressing cover 102. Accordingly, the copy / facsimile multifunction peripheral 100 places an original on the platen glass 10 of the reading placement table 101 to read an image as a flat bed scanner, and reads an image using the paper conveying apparatus 1. Both are possible. Although not shown in the figure, the copy / facsimile multifunction peripheral 100 has an operation panel for inputting the start of reading of an original, an image recording unit for recording an image on a recording sheet, and a transmission for transmitting an image. And a well-known configuration such as a paper feed cassette that supplies recording paper for recording the read image, and these well-known configurations are examples and arbitrary.

  As shown in FIG. 2, the sheet conveying apparatus 1 is disposed as an ADF in the document pressing cover 102 and continuously feeds the document onto the image reading surface P of the platen glass 10. The document fed from the document tray 2 to the transport path by the sheet transport device 1 is reversed so as to make a U-turn from the top to the bottom along the paper guide 3 and reaches the image reading surface P. When passing, the image of the original is read by the reading unit 11 and discharged to the discharge tray 4 below the original tray 2. The original transported by the paper transport device 1 is a so-called plain paper of various sizes generally used for copying and printers, and has a thickness that can pass through the transport path and is along a U-shaped transport path in the horizontal direction. It can be bent.

  The reading unit 11 is provided in the reading table 101, and includes a light source 12 for irradiating light to the image reading surface P, a reflection mirror 13 for guiding reflected light R from the document in a predetermined direction, and a reflection. A so-called reduction optical system CCD comprising a condenser lens 14 for converging the light R, and a charge coupled device (hereinafter referred to as “CCD”) 15 for converting the converged light into an electric signal and outputting the electric signal. It is a reading unit. The reading unit 11 configured as described above scans the image of the document being conveyed on the conveyance path with the image reading surface P, and guides the reflected light R from the document to the CCD 15 to form an image. The image signal converted into an electric signal is subjected to analog / digital conversion, shading processing, etc., and then recorded on a recording sheet by an image recording unit such as a printer, or transmitted by a transmission unit such as CODEC.

  FIG. 3 is an enlarged cross-sectional view of the vicinity of the sheet conveying apparatus 1. As shown in FIG. 3, the sheet conveying apparatus 1 includes a document tray 2 that holds a plurality of documents in a stacked state, and a downstream side of the document tray 2. A paper guide 3 provided on the side, a paper discharge tray 4 for carrying the originals after conveyance in a stacked state, a pickup roller 5 and a paper feed roller 6 for feeding the originals on the original tray 2 to the conveyance path, A separation pad 7 that is in pressure contact with the paper roller 6 and a conveyance roller 8 that conveys the document in the conveyance path are provided.

  As shown in the figure, the document tray 2 is provided on the upper part of the document pressing cover 102 so as to be slightly inclined in the direction in which the document is supplied, so that a plurality of documents are stacked on the upper surface thereof. It has become. When the user places a document on the document tray 2, the document is placed so that the front end of the document is aligned with the inclined lower end side of the document tray 2. Although not shown in the drawing, the document tray 2 is provided with a variable guide member that regulates the position of the document in the width direction and prevents the document from being obliquely fed.

  On the downstream side of the document tray 2, a paper guide 3 is disposed in the document pressing cover 102, the paper guide 3 serves as an inner guide surface of the conveyance path, and the housing of the document pressing cover 102 is an outer guide of the conveyance path. A horizontal U-shaped conveyance path that communicates with the paper discharge tray 4 is formed. The outer guide surface constituting the conveyance path may be provided with a guide plate formed by curving an iron plate or the like. However, by using the document pressing cover 102 together with the housing, the number of parts is reduced and the assembly is easy. This is preferable. A document guide 9 is provided on the upper surface of the paper guide 3. The document guide 9 has a curved portion 90 and a guide film 91 that are curved upward toward the roller surface of the paper feed roller 6, and the document that is fed from the document tray 2 by the curved portion 90 and the guide film 91. Is guided to the separation pad holder 70. The separation pad holder 70 has a separation pad 7 affixed to the upper surface thereof, and an inclined surface 70a for guiding a document to the separation pad 7 is formed. The document guided along the guide film 91 is It is guided so as to come into contact with the roller surface of the paper feed roller 6 along the inclined surface 70a. By the curved portion 90 and guide film 91 of the document guide 9 and the inclined surface 70a of the separation pad holder 70, a plurality of documents placed on the document tray 2 are stored in a stacked state without flowing into the conveyance path. In addition, when the originals are placed on the original tray 2, the originals that are in close contact with each other are scraped by the leading edge of each original being obliquely displaced along the curved portion 90 and the inclined surface 70a. It is easy to separate the original from the uppermost paper, and double feeding is prevented. Further, the guide film 91 reliably and smoothly guides the leading edge of the document to a predetermined position without the document being caught on the joint portion between the document guide 9 and the separation pad holder 70. Note that the separation pad holder 70 and the document guide 9 are not necessarily provided in the entire width direction of the upper surface of the paper guide 3.

  The paper feed roller 6 is disposed above the paper guide 3 and rotates while being in pressure contact with the original fed from the original tray 2 to feed the original into the conveyance path. A roller made of silicon and EPDM (Ethylene-Propylene-Diethylene Methylene Linkage) is fixed on the roller shaft 60. The roller shaft 60 is rotatably supported by the paper guide 3. A configuration in which the paper guide 3 supports the roller shaft 60 will be described in detail later. Further, a pickup roller 5 for feeding the uppermost sheet of the document placed on the document tray 2 is disposed upstream of the paper feed roller 6. Similarly to the paper feed roller 6, the pick-up roller 5 also rotates the paper while being brought into pressure contact with the original, thereby bringing the original into the conveyance path. The pickup roller 5 swings up and down by a paper supply clutch (not shown). It is supported by the moving arm 51 and can contact and separate from the document guide 9. By the swinging of the swing arm 51, the pickup roller 5 is separated from the document guide 9 in a normal state such as when a document is placed on the document tray 2, and contacts the uppermost sheet of the document when the document is fed. When the pickup roller 5 and the paper feed roller 6 rotate, the uppermost sheet of the original is fed into the conveyance path. A cork pad 92 is affixed to the upper surface of the document guide 9 at a position in contact with the pickup roller 5, and the pickup roller can be used even when only one document is placed on the document tray 2. 5 and the cork pad 92 can nip the original and reliably feed it to the conveyance path. Since the pickup roller 5 can be lowered until it comes into contact with the document guide 9, even if the thickness of the bundle of documents changes depending on the number of documents, the pickup roller 5 can always contact the uppermost sheet. Although not shown in the drawing, the presence / absence of a document on the document tray 2 is detected by a document set sensor, and based on the detection signal, the control means controls the pickup roller 5, the swing arm 51, and the paper feed roller 6. The operation is controlled.

  On the other hand, a separation pad 7 is provided below the paper feed roller 6. The separation pad 7 has a friction coefficient with respect to the original that is lower than the friction coefficient with respect to the original of the paper feed roller 6 and higher than the friction coefficient between the originals, and can be formed of, for example, urethane resin. Such a separation pad 7 is stuck on the upper surface of the separation pad holder 70. The separation pad holder 70 is slidably locked at a predetermined position of the paper guide 3 and is urged upward by a coil spring 71, whereby the separation pad 7 is moved to the roller surface of the paper feed roller 6. And can be rotated downward in accordance with the thickness of the original passing through the pressure contact portion. Although not shown in detail in the drawing, the separation pad 7 does not need to be provided in the entire axial direction of the paper feed roller 6, and a part of positions through which various originals having the minimum reading width to the maximum reading width pass in common. In this case, it is sufficient to provide a frictional force capable of separating the document.

  Further, on the laterally U-shaped conveyance path, conveyance rollers 8 for conveying the document are respectively disposed at positions immediately downstream of the folded portion and the most downstream of the conveyance path. The transport roller 8 rotates when a rotational force from a driving source such as a motor is transmitted to the roller shaft 80, and the roller shaft 80 is also rotatably supported by the paper guide 3. A driven roller 81 that is driven by the rotation of the conveying roller 8 is provided at a position facing the conveying roller 8 so as to sandwich the conveying path, and the document is conveyed while being nipped by the conveying roller 8 and the driven roller 81. It has become. The arrangement of the conveyance rollers 8 is an example, and it is of course possible to appropriately increase or decrease the number of the conveyance rollers 8 according to the shape and distance of the conveyance path.

  Next, the configuration of the paper guide 3 will be described in detail with reference to FIGS. As shown in FIG. 4, the paper guide 3 includes a paper guide main body 30 that forms a laterally U-shaped conveyance path and side frames 31 provided on both sides of the paper guide main body 30, which are integrally formed of a plastic material. Thus, a static elimination guide 32 is disposed on the downstream side of the folded portion of the paper guide body 30, and a grounding member 33 for grounding the static elimination guide 32 is disposed on the side frame 31.

  The plastic material of the paper guide main body 30 and the side frame 31 is a synthetic resin that can be integrally molded using a mold. For example, ABS, high-impact polystyrene, or a material in which a reinforcing material such as glass fiber is added thereto may be used. it can. The paper guide main body 30 has a guide surface 300 having a shape in which the upstream side of the upper surface is inclined in the same manner as the document tray 2 and the downstream side is curved downward, and the guide surface 300 is a U-shaped sideways. An inner guide surface on the upstream side of the folded portion of the transport path is formed. Paper feeding ribs 301 are arranged in the width direction at the curved portion of the guide surface 300, and the frictional force applied to the document by reducing the contact surface with the document that makes a U-turn while sliding on the guide surface 300. Has been reduced.

  The side frames 31 are plate-shaped integrally formed on both sides of the paper guide body 30, and both side frames 31 have bearings for the roller shaft 60 of the paper feed roller 6 and the roller shaft 80 of the transport roller 8. Through-holes 310 are formed, and the through-holes 310 rotatably support the roller shafts 60 and 80 so that the paper feed roller 6 and the transport roller 8 are in a predetermined position with respect to the paper guide main body 30. Placed in. Although not shown in the figure, each of the through holes 310 is rotatably inserted, and a drive gear is provided at one end of each of the roller shafts 60 and 80. The rotation of the motor is transmitted to the drive gear, so that each roller The shafts 60 and 80 are respectively rotated.

  Further, the static elimination guide 32 disposed on the downstream side from the folded portion of the paper guide main body 30 is formed by bending and bending a conductive member such as a sheet metal as shown in FIGS. 4 and 5. The lower surface 320 of the static elimination guide 32 constitutes an inner guide surface on the downstream side of the folded portion of the lateral U-shaped conveyance path. When the document being conveyed comes into contact with such a static elimination guide 32, static electricity of the document caused by friction with the paper guide body 30 is removed. The friction between the document and the paper guide main body 30 is considered to be strongest at the folded portion where the document is U-turned. Therefore, by providing the static elimination guide 32 downstream from the folded portion, Static electricity generated by friction can be efficiently removed.

  Further, on both sides of the static elimination guide 32, contact walls 321 are bent vertically upward from the lower surface 320, respectively. The contact wall 321 is a support bracket for swingably supporting the static elimination guide 32 with respect to the paper guide main body 30 and constitutes a contact surface that is electrically connected to the ground member 33. is there. Each contact wall 321 extends further downstream from the downstream end of the lower surface 320 and reaches the most downstream side of the conveyance path, and the conveyance roller 8 disposed at the most downstream position of the contact wall 321 at the most downstream side. Through holes 322 through which the roller shafts 80 are inserted are respectively formed. In addition, a long hole 323 is formed in the vicinity of the center upper end of each contact wall 321. Such a contact wall 321 is located inside each of the side frames 31 when the static elimination guide 32 is assembled to the paper guide main body 30 and the side frame 31, and the through hole 322 has a through hole in the side frame 31. By inserting the roller shaft 80 of the conveyance roller 8 supported by the bearing 310, the static elimination guide 32 is swingably attached between the side frames 31. Further, a screw is inserted into the long hole 323 and is loosely screwed to the side frame 31, so that the swing of the static elimination guide 32 is limited to the range of the long hole 323. As described above, by attaching the static elimination guide 32 to the roller shaft 80 of the transport roller 8, when the plastic material and the metal material are separated for recycling, the roller shaft 80 of the transport roller 8 is removed from the side frame 31. Since the static elimination guide 32 can also be removed easily, the disassembling work of the paper guide 3 for recycling is simplified. Further, by inserting and removing a screw with respect to the elongated hole 323, the static elimination guide 32 can be fixed at a position constituting the inner guide surface or can be swung, so that maintenance work is easy.

  In addition, positioning members 324 are formed on both sides of the lower surface 320 of the static elimination guide 32 so that a part protrudes downward. The positioning member 324 is formed by punching a part of both sides of the lower surface 320. When the positioning member 324 comes into contact with the document reading surface P, the lower surface 320 of the static elimination guide 32 is changed to the document reading surface P. Therefore, the original is passed between the lower surface 320 and the original reading surface P. The protruding dimension of the positioning member 324 is appropriately set in consideration of the subject depth of the image reading unit, the thickness of the document conveyed between the static elimination guide 32 and the image reading surface P, and the like. In the case of using a CCD reading unit of a reduction optical system as in the embodiment, it is preferably about 2 to 3 millimeters, and more preferably about 1 millimeter to stabilize the read image quality. Note that the positioning member according to the present invention is integrally formed by projecting from the lower surface 320 of the static elimination guide 32 like the positioning member 324. For example, the positioning member projects upward from the platen glass 10 constituting the image reading surface P. It is possible to adopt another configuration such as to be interposed between the lower surface 320 of the static elimination guide 32 and the image reading surface P.

  Further, as shown in FIG. 3, the static elimination guide 32 assembled as the paper guide 3 is biased downward by a coil spring (biasing member) 34. The paper guide main body 30 is provided with a pair of left and right support portions 302 for fitting the coil springs 34, and the static elimination guide 32 is similarly provided with a pair of left and right support portions 325. Are respectively inserted into the support portions 302 and 325 to apply a downward urging force to the static elimination guide 32. Therefore, as shown in FIG. 6, the static elimination guide 32 whose oscillation is limited within a certain range by a screw (not shown) inserted through the elongated hole 323 of the contact wall 321 has no reaction force from below. As long as it is located at the lower limit of the swing range. On the other hand, when the positioning member 324 comes into contact with the platen glass 10 constituting the document reading surface P and the reaction force from below is generated in the static elimination guide 32, the static elimination guide 32 moves upward according to the reaction force. Swing to. The range of the vertical movement of the static elimination guide 32 can be set as appropriate depending on the length of the elongated hole 323. As described in detail below, the range between the platen glass 10 of the reading table 101 and the document pressing cover 102 is set. In order to absorb a slight gap by the vertical movement, the upper limit of the range is set above the position of the static elimination guide 32 in a state where the document pressing cover 102 is completely closed, and the lower limit is the platen glass 10 and the document pressing cover 102. It is preferable that the gap is formed below the position of the static elimination guide 32 in a state where the document pressing cover 102 is completely closed.

  As described above, the sheet conveying apparatus 1 is provided in the document pressing cover 102. As shown in FIG. 1, the document pressing cover 102 is placed on the platen glass 10 of the reading table 101. When the reading unit 11 is used as a flat bed scanner by placing a document, the document is opened and closed as needed to press the document onto the platen glass 10. On the other hand, when image reading is performed using the sheet conveying apparatus 1 as an ADF, the document presser cover 102 is closed. However, when the user closes the document presser cover 102, the document presser cover 102 is not completely closed or the document presser cover is closed. In some cases, the cover 102 rebounds when the cover 102 is closed, and a slight gap is generated between the platen glass 10 of the reading table 101 and the document pressing cover 102. The gap affects the positional relationship between the lower surface 320 of the static elimination guide 32 and the image reading surface P of the platen glass 10. However, as described above, in the paper conveying apparatus 1, the static elimination guide 32 is swingable. Therefore, it is constantly urged downward and can move up and down with respect to the image reading surface P within a predetermined range. By swinging downward until contact, the positional relationship between the lower surface 320 and the image reading surface P is set to a predetermined dimension regulated by the positioning member 324. On the other hand, when the gap as described above does not occur, the neutralization guide 32 is opposed to the biasing force of the coil spring 34 when the document pressing cover 102 is completely closed after the positioning member 324 contacts the document reading surface P. Swings upward, so that the positional relationship between the lower surface 320 and the image reading surface P is a predetermined dimension regulated by the positioning member 324. In this way, the vertical movement of the static elimination guide 32 absorbs a slight gap generated between the platen glass 10 of the reading table 101 and the document pressing cover 102, and the lower surface 320 and the image reading regardless of the presence or absence of the gap. The positional relationship with the surface P can be a predetermined dimension regulated by the positioning member 324.

  As shown in FIGS. 4 and 6, the grounding member 33 is obtained by processing a conductive member such as a sheet metal into a strip shape, and a plurality of branch portions 331 to 335 are appropriately branched in the vertical direction from the base portion 330. The branch portions 331 to 333 are electrically connected to the roller shafts 60 and 80, respectively, the branch portion 334 is electrically connected to the static elimination guide 32, and the branch portion 335 is used to fix the grounding member 33 to the side frame 31. It is used for. Such a grounding member 33 is grounded, so that charges are released from the roller shafts 60 and 80 and the charge removal guide 32.

  The grounding member 33 is fixed to the side frame 31, but as shown in FIG. 6, the side frame 31 is reinforced on the outer surface of the side frame 31 and at a position parallel to the grounding member 33 and the side frame 31. Reinforcing reinforcing ribs 311 are formed, positioning pins 312 for positioning the grounding member 33 are protruded laterally from the reinforcing ribs 311, and screw holes 313 for fixing the grounding member 33 are formed. A screw hole 313 for fastening the branch portion 335 passes through the side frame 31, and a tip of a screw (not shown) inserted into the insertion hole 338 of the branch portion 335 and screwed into the screw hole 313 is the static elimination guide 32. By inserting into the elongated hole 323, the branch portion 335 and the side frame 31 are fastened, and the swinging range of the static elimination guide 32 is limited. On the other hand, an insertion hole 337 for inserting the positioning pin 312 and an insertion hole 338 for inserting a screw screwed into the screw hole 313 are appropriately formed in the base 330 of the grounding member 33, and the insertion hole 337 is inserted. The grounding member 33 is fixed in close contact with the reinforcing rib 311 of the side frame 31 by inserting the positioning pin 312 through the screw hole and inserting a screw (not shown) into the insertion hole 338 and screwing into the screw hole 313. Is done. The branch portions 331 to 333 of the grounding member 33 thus fixed are electrically connected in a state where the roller shafts 60 and 80 are rotatable. However, such a connection structure is well known and detailed description thereof is omitted.

Hereinafter, a connection structure between the branch portion 334 of the grounding member 33 and the static elimination guide 32 will be described in detail.
As shown in FIGS. 7 to 9, the branch portion 334 branches vertically downward from the base portion 330 and is bent inward of the side frame 31 in the vicinity of the center thereof, thereby forming a semicircular protrusion 339. Has been. Specifically, the branch portion 334 branches from the base portion 330, is bent so as to contact the outer surface of the side frame 31, and extends vertically downward in contact with the outer surface. The side frame 31 is provided with a rectangular grounding window 314 at a position corresponding to the semicircular protrusion 339, and a cross section in the extending direction of the branch part 334 is semicircular through the grounding window 314. The semicircular protrusion 339 that is bent so as to protrude toward the inside of the side frame 31 and the curved surface 339b is in contact with the contact wall 321 of the charge removal guide 32, so that the charge removal guide 32 and the grounding member 33 are It becomes a conductive state. The lower end of the branch portion 334 is not fixed and is a free end in contact with the outer side surface of the side frame 31, restricts the position of the semicircular protrusion 339 in the inner direction of the side frame 31, and It can move in the direction. Such a branch portion 334 is fixed in a state in which the base portion 330 is fixed to the side frame 31 so as to be elastically deformable in the outer direction of the side frame 31. Spring elasticity is applied in the swing axis direction of the guide 32, that is, in the axial direction of the roller shaft 80.

  On the other hand, as described above, the static elimination guide 32 is formed with a contact wall 321 that is bent vertically upward from both sides of the lower surface 320, and the wall surface of the contact wall 321 is a roller shaft that serves as a swing shaft. It is orthogonal to the 80 axis. The contact wall 321 is positioned inside the side frames 31 in a state assembled to the paper guide main body 30 and the side frame 31, and the outer wall surface of one of the contact walls 321 is in pressure contact with the semicircular protrusion 339. Are electrically connected. Here, the static elimination guide 32 is swung around the roller shaft 80 during assembly or maintenance, and the contact wall 321 and the semicircular protrusion 339 come into contact with and separate from each other during the swinging. If the edge 321a of the contact wall 321 comes into contact with the side end 339a of the semicircular protrusion 339 when the semicircular protrusion 339 is in a pressure contact state, the semicircular protrusion 339 is moved in the swing axis direction. There is a risk of sliding in the side direction of the side frame 31 without elastically moving and being pinched between the ground window 314 and the edge 321a of the contact wall 321 and being crushed. In order to solve such a problem, the semicircular protrusion 339 is reliably swung so that the edge 321a of the contact wall 321 contacts the curved surface 339b instead of the side end 339a of the semicircular protrusion 339. It is designed to move elastically in the axial direction.

  Further, with reference to the drawings, as shown in FIG. 7, when the static elimination guide 32 is swung to the open side and the contact wall 321 and the semicircular protrusion 339 are separated from each other, The semicircular protrusion 339 protrudes inward of the side frame 31 through the ground window 314 in a state where the lower end of the branch part 334 is in contact with the outer surface of the side frame 31. As shown in FIG. 8, when the static elimination guide 32 is swung to the mounting position side and the edge 321a of the contact wall 321 comes into contact with the semicircular protrusion 339, the edge 321a becomes a semicircular protrusion. 339 is in contact with the curved surface 339b. Further, when the static elimination guide 32 is swung, the semicircular protrusion 339 is elastically moved to the outside of the side frame 31 so that the edge 321a slides on the curved surface 339b, as shown in FIG. In addition, when the static elimination guide 32 is in the attached state, the wall surface of the contact wall 321 and the curved surface 339b of the semicircular protrusion 339 are pressed against each other. As described above, when the static elimination guide 32 is swung, the edge 321a is smoothly slid according to the curvature of the curved surface 339b by bringing the edge 321a into contact with the curved surface 339b, and the semicircular protruding portion 339 is swung. Since an overload in a direction other than the moving axis direction is not applied, the contact wall 321 and the curved surface 339b of the semicircular protrusion 339 are reliably pressed against each other without crushing the semicircular protrusion 339. Can be made.

  As shown in FIG. 3, an elastic film 35 is provided on the outer guide surface downstream of the folded portion of the laterally U-shaped conveyance path with respect to the paper guide 3 disposed on the document pressing cover 102. . Specifically, as shown in the figure, the upstream end of the elastic film 35 is fixed to a position of the housing of the document pressing cover 102 and constituting the outer guide surface of the conveyance path immediately after the image reading surface P. The elastic film 35 on the downstream side is provided in such a manner that the elastic film 35 can be elastically deformed and the downstream end thereof is close to the lower surface 320 of the static elimination guide 32. The vertical width of the transport path is gradually narrowed toward the lower surface 320 of the static elimination guide 32. The elastic film 35 has an appropriate strength that can guide the document being conveyed so as to be brought into contact with the static elimination guide 32, and is a thin film that can be elastically deformed to the outer guide surface when the document being conveyed contacts. For example, a synthetic resin film such as polypropylene can be used. As a result, the document being conveyed comes into contact with the neutralization guide 32 and the static electricity of the document is removed. Further, as described above, the elastic film 35 is elastically deformed when the document collides, so that an excessive load is not applied to the document, and there is little influence on the document conveyance speed and direction, and the image quality of the read image is deteriorated. Minimal. The elastic film 35 is not necessarily provided so as to correspond to the entire width direction of the static elimination guide 32, and may be provided only in the vicinity of the central portion or in a pair of left and right.

  It should be noted that the configuration of the sheet conveying apparatus 1 and the copy / facsimile multifunction peripheral 100 shown in the present embodiment is merely an example, and it is needless to say that the design can be changed as appropriate without departing from the gist of the present invention. A unit is not used in combination with a flatbed scanner, but a so-called contact image sensor (hereinafter referred to as “CIS”) is used instead of a reading unit of a reduction optical system using a CCD. It is also possible to place a CCD or CIS at the opposite position of the conveyance path, etc., or to provide a document return path on the horizontal U-shaped conveyance path so as to read both sides of the document. is there.

  The present invention relates to a sheet conveying device for conveying an original to an image reading means in a scanner, a facsimile, a copying machine, or the like, which is provided with an original holding cover that can be opened and closed with respect to a reading table having an image reading surface. Equipped with an original cover, it is particularly useful in scanners, facsimiles, copiers, and the like that require small size, light weight, low cost, recyclability, and ease of assembly, disassembly, and maintenance work.

1 is a schematic perspective view showing a configuration of an upper part of a copy / facsimile multifunction peripheral 100 according to the present embodiment. 2 is a cross-sectional view showing a configuration of an upper part of the copy / facsimile multifunction peripheral 100. FIG. FIG. 3 is an enlarged cross-sectional view showing a configuration in the vicinity of the paper transport apparatus 1 3 is an exploded perspective view showing a configuration of a paper guide 3. FIG. 2 is a longitudinal sectional view showing a configuration of a paper guide 3. FIG. 3 is a side view showing the configuration of the paper guide 3. (A) is a side view of the paper guide 3 in a state where the static elimination guide 32 is swung, and (b) is a partial sectional view thereof. (A) is a side view of the paper guide 3 in a state where the static elimination guide 32 is swung, and (b) is a partial sectional view thereof. (A) is the side view of the paper guide 3 in which the static elimination guide 32 exists in an attachment position, (b) is the fragmentary sectional view. 1 is a perspective view showing an external appearance of a copy / facsimile multifunction peripheral 900. FIG.

Explanation of symbols

P Image reading surface 101 Reading table 102 Document pressing cover 1 Paper conveying device 2 Document tray 3 Paper guide 4 Paper discharge tray 6 Paper feed roller 8 Carrying roller 30 Paper guide body 31 Side frame 32 Electric discharge guide 33 Grounding member 34 Coil spring (attached) Force member)
60, 80 Roller shaft 310 Through hole (bearing)
321 Contact wall 321a Edge 324 Positioning member 339 Semicircular protrusion 339b Curved surface

Claims (1)

A document holding cover is provided that can be freely opened and closed with respect to a reading table having an image reading surface, and the paper on the document tray passes through the U-shaped conveying path in the horizontal direction to the discharge tray via the image reading surface. In the paper transport device to transport,
A paper guide main body constituting the inner guide surface of the laterally U-shaped conveyance path, and a side frame having a roller shaft bearing of a roller disposed in the conveyance path to convey paper, are integrally formed of a plastic material. The side frame is provided with a static elimination guide made of a conductive member constituting an inner guide surface downstream of the lateral U-shaped folded portion so as to be swingable so as to be vertically movable with respect to the image reading surface. A positioning member is interposed between the inner guide surface of the static elimination guide and the image reading surface, and a biasing member that biases the static elimination guide downward with respect to the image reading surface is provided. A grounding member for grounding the shaft and the static elimination guide is provided, and the grounding member is formed with a semicircular projection on the belt plate material, and the semicircular projection is a spring in the swing axis direction of the static elimination guide. Bullet The static elimination guide is provided with a contact wall orthogonal to the swing axis, and when the static elimination guide swings, the edge of the contact wall contacts the curved surface of the semicircular protrusion. A paper conveying apparatus characterized in that the semicircular protrusion is brought into contact and elastically moved so that the wall surface of the contact wall and the curved surface of the semicircular protrusion are pressed against each other .

Images