JP3747926B2 - 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 reading position.

  FIG. 12 is a schematic perspective view showing the external appearance of a copy / facsimile multifunction peripheral 900 equipped with an ADF. As shown in the figure, 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 of the original is conveyed by an image reading means such as a CCD provided in the reading table 901 when passing through a reading position on the platen glass in the conveying process. Reading is to be performed.

  In the conventional paper transport device, a pick-up roller is disposed on the document tray 906 in order to feed a plurality of documents stacked on the document tray 906 one by one into the transport path, and on the downstream side thereof. The paper feed roller and the retard roller are arranged in a state where the respective roller surfaces are in contact with the opposite positions of the conveyance path, and the document fed from the document tray 906 by the pickup roller is a nip between the paper feed roller and the retard roller. The sheets are separated one by one on the surface and fed into the conveyance path. In general, the feed roller and the retard roller are arranged such that a retard roller disposed inside the conveyance path is movable up and down, and the retard roller is urged against the feed roller by a spring or the like, so that the roller surfaces are pressed against each other. The nip pressure is adjusted by adjusting the position of the spring, but the retard roller is provided with a drive transmission mechanism or the like, and these mechanisms are the limiting conditions. Adjustment of the nip pressure was troublesome. On the other hand, a configuration that simplifies the configuration of the adjustment member for the nip pressure and can easily perform the adjustment work is desired. For example, an adjustment mechanism as described in Patent Document 1 and Patent Document 2 is provided. is there.

  On the other hand, as a configuration for separating documents one by one, there is a configuration in which a separation pad is disposed so as to be pressed against a sheet feeding roller instead of the retard roller (for example, Patent Document 3). Even in the configuration using the separation pad, the adjustment of the nip pressure between the paper feed roller and the separation pad is generally performed by adjusting the position of a spring that urges the pad holder that supports the separation pad.

JP 2001-31275 A JP 2001-97575 A JP 2002-179270 A

  However, scanners, facsimiles, copiers, etc. have demands for further reduction in size and weight, and cost reduction. Similarly, the paper conveyance devices equipped in these devices are also required to be reduced in size, weight, and cost. It is necessary to reduce the number of parts and simplify the assembly work. In addition, when plastic materials are used for each part of the paper transport device for the purpose of reducing the size and weight, from the viewpoint of resource recycling, etc., it is disassembled and reused for each type of material such as metal and plastic. Alternatively, it is desirable to be able to discard, and it is desirable to simplify not only the assembly workability but also the dismantling work at the time of disposal. Furthermore, it is necessary to consider the ease of molding and the strength against the urging force of a spring or the like for a part using a plastic material.

  The present invention has been made to solve the above-described problems, and can realize a reduction in size and weight, a reduction in cost, an assembly work and a disassembly work, and a nip pressure between the feed roller and the separation pad. It is an object of the present invention to provide a paper transport device that can be easily adjusted.

  The present invention includes a paper feed roller that feeds an original document into a conveyance path and a separation pad provided in pressure contact with the paper feed roller, and the original document loaded on the document tray is formed by the paper feed roller and the separation pad. In a paper conveying apparatus that separates sheets one by one and feeds them into a conveyance path, a separation is provided on a plastic paper guide that constitutes a guide surface of the conveyance path in a swingable manner, and the separation pad is pasted on the upper surface thereof A pad holder, a swing bracket provided at both ends thereof so as to allow seesaw motion by being pivotally supported by a shaft support portion integrally formed with the paper guide below the separation pad holder, and the separation pad holder A spring interposed between one end side of the swinging bracket and urging the separation pad holder toward the paper feed roller side, and engaged with the other end side of the swinging bracket and at the same time as a paper guide Characterized by comprising an adjusting screw for regulating the swinging upper limit of the swing bracket screwed with the body shaped screw hole, the.

  In the present invention, the swing bracket is housed in a recess formed integrally with the paper guide, and a through hole for adjusting the adjustment screw is formed in a cover covering the recess. Features.

  Further, according to the present invention, the concave portion is formed in the vicinity of a seating position of a feeding roller that feeds a document placed on a document tray into a conveyance path, and a cork is formed on an upper surface of the cover including the seating position of the feeding roller. A pad is attached and the through hole is sealed.

  According to the present invention, since the shaft support portion and the screw hole are integrally formed in the paper guide, the number of parts and the assembly man-hour of the nip pressure adjusting mechanism between the paper feed roller and the separation pad can be reduced, and the swinging motion can be reduced. Mounting of bracket and adjustment screw is easy.

  In addition, a through hole for adjusting the adjustment screw is drilled in the cover that covers the concave portion in which the swing bracket is accommodated, so that a mechanism for adjusting the nip pressure by the swing bracket and the adjustment screw is assembled to the paper guide. After assembling the separation pad holder, the cover, and the paper feed roller, it can be easily adjusted while detecting the actual nip pressure.

  In addition, the concave portion is formed in the vicinity of the seating position of the feeding roller, so that the nip pressure can be easily adjusted, and the cover through-hole is sealed to prevent dust from entering the concave portion. Further, by sticking a cork pad on the upper surface of the cover, the feeding of the document by the feeding roller is ensured.

  FIG. 1 is a diagram showing a cross section 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 includes a reading table 101 on which a platen glass 10 on which a document to be read is placed is disposed, and a document that presses and fixes the document onto the platen glass 10. And a presser cover 102. 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.

  The sheet conveying apparatus 1 described in detail below is disposed as an ADF in the document pressing cover 102 and continuously feeds the document to the reading position P of the platen glass 10. The original fed from the original tray 2 to the conveyance path is reversed so as to make a U-turn from the upper side to the lower side along the paper guide 3 and reaches the reading position P. When the original passes through the reading position P, the reading unit 11 is turned on. As a result, the image of the original is read 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 that emits light to the reading position P, a reflecting mirror 13 that guides reflected light R from the document in a predetermined direction, and reflected light. A so-called reduction optical system CCD reading comprising a condensing lens 14 for converging R and a charge coupled device (hereinafter referred to as “CCD”) 15 for converting the converged light into an electric signal and outputting it. Is a unit. By the reading unit 11 configured as described above, the image of the document conveyed on the conveyance path is scanned at the reading position P, and the reflected light R from the document is guided to the CCD 15 and imaged. The image signal converted into an electrical 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. 2 is an enlarged cross-sectional view of the vicinity of the sheet conveying apparatus 1. As shown in the figure, 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 that carries the conveyed originals in a stacked state, a pickup roller (feeding roller) 5 for feeding the originals on the original tray 2 to the conveyance path, and a paper supply roller 6, a separation pad 7 that is in pressure contact with the paper feed roller 6, a conveyance roller 8 that conveys the document in the conveyance path, and a locking cover (cover) 9 provided below the pickup roller 5. .

  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 cover main body 102a and the ADF cover 102b of the document pressing cover 102 are provided. Serves as an outer guide surface of the conveyance path, and forms a laterally U-shaped conveyance path communicating with the paper discharge tray 4. The outer guide surface constituting the conveyance path may be provided with a guide plate formed by curving an iron plate or the like in the document pressing cover 102 separately. However, the cover main body 102a and the ADF cover 102b of the document pressing cover 102 and the outer guide surface It is preferable to integrally mold with a plastic material because the number of parts is reduced and assembly is facilitated.

  As shown in FIG. 3, the paper guide 3 is assembled with the pickup roller 5, the paper feed roller 6, the separation pad 7, the separation pad holder 70, the transport roller 8, the locking cover 9, and the like to hold the document presser. The cover 102 is disposed on the cover main body 102a. Although not shown in the figure, the paper guide 3 is also assembled with a drive unit such as a motor and a drive gear, and the ADF cover 102b is disposed on the cover body 102a so as to be opened and closed.

  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. The static elimination guide 32 is disposed downstream of the folded portion of the paper guide main body 30. 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. Further, a recess 303 for mounting the separation pad holder 70 and the locking cover 9 is formed at the center of the guide surface 300 in the width direction and below the pickup roller 5 and the paper feed roller 6. . The detailed configuration of the recess 303 will be described later.

  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 serve as bearings for the roller shafts 60 and 80 so as to support the paper feed roller 6 and the conveyance roller 8 at predetermined positions with respect to the paper guide body 30. It has become. Although not shown in the figure, the roller shafts 60 and 80 are rotatably inserted into the through holes 310 that are paired with the side frames 31, respectively. A drive gear is provided at the outer end of 31 and the rotation of the motor is transmitted to the drive gear so that each of the roller shafts 60 and 80 is rotated. The drive transmission for transmitting the drive from such a motor. The side frame 31 also supports the gear. In FIG. 4, the drive gears of the roller shafts 60 and 80 are provided outside the side frame 31 on the front side of the figure. The side frame 31 is provided with a gear stud 311 that supports the drive transmission gear. ing. The arrangement of the gear stud 311 is appropriately set according to the positions of the roller shafts 60 and 80, the mounting position of the motor, and the diameter of the gear, and is not necessarily constant, but in the present embodiment, the four gear studs 311 are arranged. Is provided at a predetermined position of the side frame 31 so as to protrude outward in the horizontal direction. Each of these gear studs 311 is also integrally formed of a plastic material together with the paper guide main body 30 and the side frame 31. Further, a screw hole 312 for screwing a bracket 33 to which a drive unit (not shown) such as a motor is attached, a reinforcing rib 313 for reinforcing the strength of the side frame 31, and the like are also integrally formed. As described above, the paper guide main body 30, the side frame 31, the through hole 310 serving as a bearing, the gear stud 311 and the like are integrally formed, so that the side frame 31 can be attached to the paper guide main body 30, The work of attaching the gear stud 311 to the frame 31 becomes unnecessary, and the number of parts and the number of assembly steps are reduced.

  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. Further, on both sides of the downstream end of the static elimination guide 32, projecting pieces 321 are bent vertically upward from the lower surface 320, and through holes 322 are formed in the projecting pieces 321, respectively. The roller shaft 80 of the conveying roller 8 that is supported by the through hole 310 of the side frame 31 is inserted into the through holes 322 of the projecting pieces 321, so that the static elimination guide 32 can swing between the side frames 31. It is attached. Further, on both sides of a predetermined position of the static elimination guide 32, projecting pieces 323 are bent vertically upward from the lower surface 320, and each projecting piece 323 is provided with a long hole 324, respectively. Screws are inserted into the long holes 324 of the projecting pieces 323 and screwed to the side frame 31, whereby the swing of the static elimination guide 32 is limited to the range of the long holes 324. As shown in FIG. 2, the static elimination guide 32 assembled as the paper guide 3 is urged downward by a coil spring 35 and swings upward in a certain range in accordance with a reaction force from a document or the like passing through the conveyance path. It becomes possible to move. 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, by attaching the static elimination guide 32 to the shaft of the transport roller 8, when separating the plastic material and the metal material for recycling, the static elimination guide 32 can be easily removed by removing the shaft of the transport roller 8 from the side frame 31. Since it can be removed, the disassembling work of the paper guide 3 for recycling is simplified. In order to quickly remove static electricity that has moved to the static elimination guide 32, the static elimination guide 32 is preferably electrically connected to a conductive member such as an apparatus frame and grounded.

  On the other hand, the cover main body 102a of the document presser cover 102 is also made of a synthetic resin that can be integrally formed using a mold, like the paper guide main body 30 and the side frame 31, for example, ABS, high impact polystyrene, What added reinforcing materials, such as glass fiber, to these can be used. As shown in FIGS. 3 and 6, the cover body 102 a has an opening 20 formed in the attachment portion of the paper guide 3, and the original conveyed along the paper guide body 30 is platen glass in the opening 20. The image is read by the reading unit 11 after passing the reading position P on the image 10. As shown in FIG. 6, the upstream side and the downstream side of the opening 20 are guide surfaces 21 and 22 that are inclined upward from the opening 20, respectively, and these guide surfaces 21 and 22 are laterally U-shaped. This constitutes an outer guide surface on the downstream side of the folded portion of the conveyance path and upstream and downstream of the reading position P. Also on the guide surfaces 21 and 22, paper feeding ribs 23 and 24 are arranged in the width direction, respectively, to reduce friction with the document being conveyed while sliding on the guide surfaces 21 and 22. Further, three or two notches 21a are formed in the width direction at the downstream ends of the guide surfaces 21 and 22, respectively, and a driven roller 81 facing the conveying roller 8 is formed in the notches 21a and 22a. It is arranged. As described above, by integrally forming the guide surfaces 21 and 22 constituting the conveyance path on the cover main body 102a of the document cover 102, it is not necessary to attach the guide member to the cover main body 102, and the number of parts and the number of assembly steps are reduced. Reduced.

  As shown in FIG. 2, an elastic film 36 is provided on the guide surface 22 of the document pressing cover 102a. Specifically, as shown in the figure, the upstream end of the elastic film 36 is fixed to the upstream end of the guide surface 22, and the elastic film 36 downstream of the fixed portion is not fixed to the guide surface 22 and is elastically deformed. The elastic film 36 is disposed so as to be in contact with the lower surface 320 of the static elimination guide 32. With the elastic film 36 arranged in this way, the vertical width of the conveyance path formed by the lower surface 320 of the static elimination guide 32 and the guide surface 22 on the downstream side from the reading position P is directed toward the lower surface 320 of the static elimination guide 32. It is gradually narrowed. The elastic film 36 has a moderate strength that can guide the document being conveyed so as to come into contact with the static elimination guide 32, and is a thin film that can be elastically deformed to the guide surface 22 when the document being conveyed abuts. For example, a synthetic resin film such as polypropylene can be used. When the original being conveyed on the elastic film 36 collides with the elastic film 36, the elastic film 36 is once elastically deformed so that the downstream side of the elastic film 36 approaches the guide surface 22, and then when the original is further conveyed, the original force is caused by the elastic force. Then, the original is guided to the charge eliminating guide 32. 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 36 is elastically deformed at the time of document collision, so that an excessive load is not applied to the document, and the influence on the document conveying speed and direction is small, and the quality of the read image is deteriorated. Minimal. Note that the elastic film 36 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. Further, in the case where the paper passing property between the static elimination guide 32 and the elastic film 36 is given the highest priority, the downstream end of the elastic film 36 is not brought into contact with the lower surface 320 of the static elimination guide 32 and a slight gap is left. Good.

As shown in FIG. 2, a separation pad holder 70 and a locking cover 9 are provided on the upper surface of the paper guide 3 configured as described above.
The separation pad holder 70 supports the separation pad 7 and is swingably attached in the recess 303 of the paper guide 3. As shown in FIG. 7, the separation pad holder 70 has a substantially cubic shape with a hollow bottom surface, and a separation pad receiving portion 700 for attaching the separation pad 7 is formed on the top surface. An inclined surface 701 for guiding the document to the separation pad 7 is formed at the upstream corner of the separation pad receiving portion 700. A state where the separation pad 7 is flush with the upper surface of the separation pad holder 70 or slightly lowered in the separation pad receiving portion 700 so that the document guided by the inclined surface 701 does not contact the end of the separation pad 7. Is pasted. At the lower end of the upstream side surface of the separation pad holder 70, two notches 702 are formed, and a swing shaft 703 is provided so as to cross the vicinity of the lower end of the notch 702. The separation pad holder 70 is slidably attached to the paper guide 3 by the 703 being locked to the paper guide 3 and the locking cover 9. On the other hand, on the downstream side surface of the separation pad holder 70, restriction claws 704 are projected at two locations. The restricting claw 704 is for engaging the paper guide 3 to restrict the swing range of the separation pad holder 70. A circular hole serving as a spring receiving portion 705 is formed in the inner space of the separation pad holder 70, and is attached to the paper guide 3 so as to be swingable by a coil spring (not shown) fitted into the spring receiving portion 705. The separated separation pad holder 70 is biased upward. The separation pad holder 70 having such a configuration is also integrally formed using a plastic material.

  The locking cover 9 is fitted into the concave portion 303 of the paper guide 3 so as to cover the upstream portion of the concave portion 303 and lock the separation pad 70 so as to be swingable. As shown in FIG. 8, the locking cover 9 is a flat plate having a substantially rectangular shape in plan view in which an inclined surface 90 is formed in the vicinity of the downstream end. A concave portion 91 for attaching a cork pad (not shown) is formed on the upper surface, and a through hole 92 is formed in the approximate center of the concave portion 91. The through-hole 92 is for inserting an adjusting tool such as a driver into the recess 303 covered by the locking cover 9 and is sealed with a cork pad except during adjustment. The inclined surface 90 is for guiding a document to the inclined surface 701 of the separation pad holder 70, and the guide reaching the inclined surface 701 of the separation pad holder 70 on the inclined surface 90 as shown in FIG. A film 93 is affixed so that a document fed from the document tray 2 is smoothly guided to the separation pad 70. Further, on the lower end side of the side surface on the downstream side of the locking cover 9, shaft locking pieces 94 are projected in two places. The corner formed by the side surface and the shaft locking piece 94 locks the swing shaft 703 of the separation pad holder from the lower side and the upstream side in a state where the locking cover 9 is assembled to the paper guide 3. can do. Further, locking claws 95 are provided on both side surfaces of the locking cover 9 in the width direction. The locking claw 95 is so-called snap fit, and an L-shaped elastic portion 950 is projected from both side surfaces, and a claw portion 951 is formed at the tip of the elastic portion 950. The locking cover 9 having such a configuration is also integrally formed using a plastic material.

Hereinafter, the assembly of the separation pad 7 and the separation pad holder 70 and the locking cover 9 to the paper guide 3 and the nip pressure adjusting mechanism of the separation pad holder 70 will be described.
As shown in FIGS. 5, 9, and 10, the separation pad holder 70 and the latch are located at the center in the width direction of the guide surface 300 of the paper guide 3 and below the pickup roller 5 and the paper feed roller 6. A recess 303 for mounting the cover 9 is formed. The downstream side of the recess 303 has a size that allows the separation pad holder 70 to be inserted therein. A shaft locking portion 304 for swingably supporting the separation pad holder 7 on the bottom surface thereof, and a swing bracket 71. A shaft support portion 305 is erected so as to be swingable. A pair of shaft locking portions 304 are arranged in the width direction of the recess 303, and the support column 304a extends upward from the bottom surface of the recess 303, and is locked from the upper end of the support column 304a to the downstream side. The part 304b has a protruding shape. The swinging shaft 703 of the separation pad holder can be locked from the upper side and the downstream side by the corner formed by the support column 304a and the locking portion 304b. Further, an auxiliary support portion 304c is formed across the downstream side surface of the support column 304a and the bottom surface of the recess 303, and the strength of the support column 304a is reinforced. The shaft support portion 305 is formed by recessing a bearing portion 305b that is received on the upper end of a support wall 305a that is erected upward from the bottom surface of the recess 303 so as to support the swing shaft 703 of the separation pad holder 7. . In addition, restriction grooves 306 are formed at two locations from the downstream side wall of the recess 303 to the bottom surface. On the other hand, on the upstream side of the concave portion 303, a carrying portion 307 carrying the locking cover 9 is formed, and the center of the carrying portion 307 is equivalent to the downstream side of the concave portion 303 so that the swing bracket 71 can be inserted. A screw hole 308 for screwing the adjustment screw 72 is formed on the bottom surface. In addition, a locking groove 309 is formed from both sides of the carrying portion 307 to both side walls of the recess 303. Each component in the recess 303 is also integrally formed in the same manner as the paper guide main body 30 and the side frame 31, and the number of parts and assembly man-hours for supporting the separation pad 70 and adjusting the nip pressure are reduced. Yes.

  When assembling the separation pad holder 70, the separation pad holder 70, and the locking cover 9 to the paper guide 3, first, as shown in FIG. 9, the swing bracket 71 and the separation pad are placed in the recess 303 of the paper guide body 30. The holder 70 is assembled. As shown in the drawing, the swing bracket 71 is a band plate-like member having a swing shaft 710 provided at the center, and an insertion hole 711 for inserting the adjustment screw 72 is provided at the upstream end portion. A spring receiving portion 712 for supporting the coil spring 73 is formed at the downstream end portion. The swing bracket 71 having such a configuration is also integrally formed using a plastic material. The swing bracket 71 is inserted into the recess 303, and the swing shaft 710 of the swing bracket 71 is fitted into the bearing portion 305 b of the shaft support portion 305, so that the swing bracket 71 is swung within the recess 303. Seesaw motion is possible with the axis as the axis. Since the shaft support portion 305 is formed with a bearing portion 305b by notching a part of the upper end of the support wall 305a in an arc shape, the swing shaft 710 of the swing bracket 71 can be easily moved from above to the bearing portion 305b. Can be fitted. Further, the adjustment screw 72 is inserted into the insertion hole 711 of the swing bracket 71 and screwed into the screw hole 308. A flange 720 is formed on the head of the adjustment screw 72. When the flange 720 engages with the periphery of the insertion hole 711, the upper swing limit of the upstream end of the swing bracket 71 is restricted. Since the screw hole 308 is formed below the upstream end of the swing bracket 71 supported by the shaft support portion 305, the adjustment screw 72 is inserted into the insertion hole 711 and the screw hole 308 of the swing bracket 71. It can be easily inserted and screwed.

  Thereafter, the coil spring 73 is fitted into the spring receiving portion 712 of the swing bracket 71 and the spring receiving portion 705 of the separation pad holder 70, and the separation pad holder 70 is locked to the shaft locking portion 304. The restricting claw 704 is assembled into the recess 303 so as to engage with the restricting groove 306. The locking portion 304b of the shaft locking portion 304 is engaged from the inside of the separation pad holder 70 to the upper side of the swinging shaft 703 of the notch 702, thereby locking the swinging shaft 703 from above and supporting pillars. When the body 304a abuts on the swing shaft 703, the swing shaft 703 is locked from the downstream side. In other words, the upper and downstream sides of the swing shaft 703 are locked by the shaft locking portion 304. Further, the urging force of the coil spring 73 acts on the separation pad holder 70, but when the restriction claw 704 is engaged with the upper end of the restriction groove 306, this position becomes the upper limit of swinging of the separation pad holder 70. Note that the separation pad 7 can be attached to the separation pad receiving portion 700 of the separation pad holder 70 either before or after the separation pad holder 70 is assembled to the paper guide 3, but it is preferable that the separation pad holder 70 be attached before the assembly. It is preferable because the work is easy.

  Next, as shown in FIG. 10, the locking cover 9 is assembled on the carrier 307 of the recess 303. At the time of assembly, both the locking claws 95 of the locking cover 9 are sandwiched between fingers and elastically deformed inward, and the shaft locking piece 94 is fitted below the swinging shaft 703 of the swinging bracket 70. While being inserted, it is inserted into the recess 303 and the elastic deformation of both the locking claws 95 is released. As a result, both the locking claws 95 are respectively engaged with the locking grooves 309 of the recess 303, and the locking cover 9 is fixed to the recess 303 with the shaft locking piece 94 locking the swinging shaft 703. In this state, the shaft locking piece 94 locks the swinging shaft 703 of the separation pad holder 70 from the lower side, and the downstream side surface of the locking cover 9 abuts on the swinging shaft 703 so that the swinging shaft 703 contacts the swinging shaft 703. The moving shaft 703 is locked from the upstream side. That is, the lower and upstream sides of the swing shaft 703 are locked by the locking cover 9.

  In this way, as shown in FIG. 11, the separation pad holder 70 is attached to the recess 303 of the paper guide 3 together with the swinging bracket 71, the adjusting screw 72 and the coil spring 73 so that the nip pressure can be adjusted. 3, a pickup roller 5, a paper feed roller 6 and the like are attached. The separation pad holder 70 is urged upward by a coil spring 73 interposed between the separation pad holder 70 and the swing bracket 71, and the paper feed roller 6 disposed above the separation pad holder 70. And the separation pad 7 are in pressure contact with each other, the nip pressure between the paper feed roller 6 and the separation pad 7 depends on the strain energy generated in the coil spring 73, but the strain energy can be adjusted by the swing position of the swing bracket 71. is there. That is, when the adjusting screw 72 is screwed into the screw hole 308, the swinging bracket 71 performs a seesaw motion, the upstream end is pushed down and the downstream end is pushed up, and the coil spring 73 is thereby pushed up. The strain energy generated in the film increases and the nip pressure increases. On the other hand, by loosening the adjusting screw 72, the upper limit of the swing of the upstream end is moved upward, and the downstream end is pushed downward by the coil spring 73, whereby the strain energy generated in the coil spring 73 is reduced. Nip pressure decreases.

  Such adjustment of the nip pressure can be easily performed by inserting a tool such as a screwdriver from the through hole 92 of the locking cover 9, and the separation pad holder 70 or the like can be removed to adjust the nip pressure. There is no need to rotate or remove the paper guide 3. Further, as shown in the drawing, it is formed in the vicinity of the seating position of the pickup roller 5 from below the paper feed roller 6, and the adjustment screw 72 is upstream of the recess 303, that is, immediately below the seating position of the pickup roller 5. Therefore, as shown in FIG. 2, in the state where the paper guide 3 is attached to the document presser cover 102, the position of the adjustment screw 72 can be easily seen, and an adjustment tool such as a driver can be easily inserted. Further, as described above, the swing bracket 71 constituting the mechanism for adjusting the nip pressure between the paper feed roller and the separation pad 7 is integrally formed using a plastic material, while the swing bracket 71 is pivotally supported. Since the shaft support portion 305 and the adjustment screw hole 308 are also integrally formed with the paper guide 3, the number of parts of the nip pressure adjustment mechanism can be reduced and the assembling work can be simplified. Further, at the time of disassembly, the metal member such as the adjusting screw 72 and the coil spring 73 can be easily separated from other plastic members. Further, as shown in the figure, the separation pad holder 70 is pivotally supported such that the swing shaft 703 is sandwiched between the shaft locking portion 304 and the locking cover 9 of the paper guide 3, thereby It is attached to the paper guide 3 so as to be swingable about the moving shaft 703. In this way, by pivotally supporting the swing shaft 703 of the separation pad holder 70 with the two members of the paper guide 3 and the locking cover 9, the shape of the shaft locking portion 304 is simplified, and the shaft locking portion 304 is simplified. Can be formed integrally with the paper guide 3.

  On the other hand, as shown in FIG. 11, except for adjustment, a cork pad 96 is attached to the recessed portion 91 of the locking cover 9 to seal the through hole 92, and the through hole 92 enters the recessed portion 303. This prevents dust such as paper dust from entering and reduces the cause of failure of the drive system and the electric system. In addition, the inclined surface 90 of the locking cover 9 and the guide film 93 and the inclined surface 70a of the separation pad holder 70 allow a plurality of originals placed on the original tray 2 to be stacked without flowing into the conveyance path. In addition, when the document is placed on the document tray 2, the leading edge of each document is obliquely displaced along the curved portion 90 and the inclined surface 70a, thereby being in a close contact state. The original is scanned and it is easy to separate the original from the uppermost paper, thereby preventing double feeding. Further, the guide film 93 reliably and smoothly guides the leading edge of the document to a predetermined position without being caught by the joint portion between the locking cover 9 and the separation pad holder 70.

  As shown in FIGS. 2 and 11, the paper feed roller 6 is disposed above the paper guide 3 and rotates while being pressed against the original fed from the original tray 2, thereby bringing the original into the conveyance path. For example, a roller made of silicon and EPDM (Ethylene-Propylene-Diene Methylene Linkage) is fixed to a metal roller shaft 60. The roller shaft 60 is rotatably supported by the paper guide 3. 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 pickup roller 5 also rotates while being in pressure contact with the original so that the original is fed into the conveyance path, and a silicon roller and an EPDM roller are fixed to the metal roller shaft 50. Being done. The pickup roller 5 is supported by a swing arm 51 that swings in the vertical direction by a paper feed clutch (not shown), and a locking cover 9 is disposed at the seating position of the pickup roller 5. The pickup roller 5 can be seated so as to come into pressure contact with the cork pad 96 of the locking cover 9 by the swing of the swing arm 51. In a normal state such as when a document is placed on the document tray 2, the pickup roller 5 is separated from the cork pad 96 and is lowered so as to come into contact with the uppermost sheet of the document when the document is fed. As the paper supply roller 6 rotates, the uppermost paper of the original is fed into the conveyance path. When one document is placed on the document tray 2, the document is nipped by the pickup roller 5 and the cork pad 96, and the document is reliably fed into the conveyance path. Since the pickup roller 5 can be lowered until it is seated on the cork pad 96, it can always come into contact with the uppermost paper even if the thickness of the bundle of documents changes depending on the number of documents. 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.

  In this way, the documents fed from the document tray 2 to the conveyance path are reliably separated one by one at the nip portion between the paper feed roller 6 and the separation pad 7. 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 affixed to the upper surface of the separation pad holder 70, and is brought into pressure contact with the paper feed roller 6 at a desired nip pressure by the nip pressure adjusting mechanism described above. For example, if an original conveyed by the pickup roller 5 to the nip portion between the paper feed roller 6 and the separation pad 7 is fed in a stacked state, the upper side of the original is the upper side of the paper feed roller 6. Since it is in pressure contact and the lower surface is in contact with the lower document, it is fed into the conveyance path according to the rotation of the paper feed roller 6. On the other hand, since the lower document is in a state where the upper surface is in contact with the upper document and the lower surface is in pressure contact with the separation pad 7, it is restrained by the separation pad 7 at the nip portion. In this way, the original is reliably separated at the nip portion between the paper feed roller 6 and the separation pad 7.

  The originals separated one by one by the paper feed roller 6 and the separation pad 7 and fed into the conveyance path are then conveyed by the conveyance roller 8 along the horizontal U-shaped conveyance path. As shown in FIG. 2, conveyance rollers 8 for conveying the document are arranged at positions immediately downstream of the folded portion of the lateral U-shaped conveyance path and at the most downstream position of the conveyance path, respectively. Is rotated by a rotational force transmitted from a driving source such as a motor to the roller shaft 80 and is 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. Accordingly, the original is conveyed to the paper discharge tray 4 through the reading position P, and the reading unit 11 reads an image at the reading position P. 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.

  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.

  INDUSTRIAL APPLICABILITY The present invention can be used as a paper transport device for transporting a document to an image reading unit in, for example, a scanner, a facsimile machine, a copying machine, and the like, and particularly requires a reduction in size and weight, cost reduction, and recyclability. Useful in scanners, facsimiles, copiers, etc.

1 is a cross-sectional view showing a configuration of an upper part of a copy / facsimile multifunction peripheral 100 according to the present embodiment. FIG. 3 is an enlarged cross-sectional view illustrating a configuration in the vicinity of the sheet conveying device 1. FIG. 5 is an exploded perspective view showing the assembly of the guide main body 102a and the paper guide 3. 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. It is a top view of the guide main body 102a. (A) is a perspective view which shows the external appearance of the separation pad holder 70, (b) is the AA sectional drawing. (A) is a perspective view which shows the external appearance of the latching cover 9, (b) is the BB sectional drawing. 4 is a schematic perspective view for explaining the assembly of the paper guide 3, the swing bracket 71, and the separation pad holder 70. FIG. 4 is a schematic perspective view for explaining the assembly of the paper guide 3 and the locking cover 9. FIG. 4 is an enlarged partial cross-sectional view showing an assembled state of the paper guide 3, the swing bracket 71, the separation pad holder 70, and the locking cover 9. FIG. 1 is a perspective view showing an external appearance of a copy / facsimile multifunction peripheral 900. FIG.

Explanation of symbols

1 Paper transport device 2 Document tray 3 Paper guide 5 Pickup roller (feeding roller)
6 Feed roller 7 Separation pad 9 Locking cover 303 Recess 305 Shaft support portion 308 Screw hole 70 Separation pad holder 71 Swing bracket 72 Adjustment screw 73 Coil spring 92 Through hole 96 Cork pad

Claims (3)

A paper feed roller for feeding the original into the transport path and a separation pad provided in pressure contact with the paper feed roller are provided, and the documents stacked on the document tray are separated one by one by the paper feed roller and the separation pad. Then, in the paper transport device that is fed into the transport path,
A separation pad holder that is swingably provided on a plastic paper guide that constitutes the guide surface of the conveyance path, and the separation pad is affixed to the upper surface of the separation pad holder;
Below the separation pad holder, a swinging bracket provided so that both end portions can be seesaw-moved by being pivotally supported by a shaft support portion integrally formed with the paper guide,
A spring interposed between the separation pad holder and one end side of the swinging bracket and biasing the separation pad holder toward the paper feed roller;
An adjustment screw that engages with the other end of the swing bracket and is screwed into a screw hole formed integrally with the paper guide to regulate the swing upper limit of the swing bracket. Conveying device.   2. The swing bracket is housed in a recess formed integrally with the paper guide, and a through hole for adjusting the adjustment screw is formed in a cover that covers the recess. The paper conveying apparatus as described. The concave portion is formed in the vicinity of a seating position of a feeding roller for feeding the document placed on the document tray into the conveyance path, and a cork pad is pasted on the upper surface of the cover including the seating position of the feeding roller. The sheet conveying apparatus according to claim 2, wherein the through hole is sealed.

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