HK1111029A - Paper transportation device - Google Patents

Description

Paper sheet conveying apparatus

This application is a divisional application entitled "sheet conveying apparatus" filed on 8/3/2004 under application number 200410055971.2.

Technical Field

The present invention relates to a sheet conveying apparatus for conveying an original to an image scanning device in a scanner, a facsimile, a copier, or the like.

Background

Scanners, facsimiles, copiers, and the like include a sheet conveying device such as an Automatic Document Feeder (ADF) that sequentially feeds a plurality of originals. Several originals stacked on an original tray can be continuously and automatically conveyed to a scanning position by a sheet conveying apparatus.

Fig. 9 is a schematic oblique view showing the appearance of a copy-and-fax multi-function peripheral 900 with an ADF. As shown in the drawing, a copy-and-fax multifunction peripheral 900 includes a scanner table 901, an original cover 902, an operation panel 903, a main chassis 904, and a plurality of paper feed cassettes 905. A platen glass on which an original is placed is provided on the scanning stage 901. The original cover 902 presses and fixes the original on the platen glass. The operation panel 903 is used for inputting a start signal of one scanning step of a document. The main frame 904 includes an image recording device which records an image on a recording paper and a transmission device which transmits the image via a public network or the like. The paper feed cassette 905 accommodates recording paper for recording a scanned image.

In the copy-and-fax multifunction peripheral 900, the ADF in the original cover 902 constitutes a sheet conveying apparatus. By the ADF, the stacked originals placed on the original tray 906 are conveyed downward to a paper discharge tray 907 located below the original tray 906 while turning the front and back sides of the originals (e.g., making a U-turn). At the time of conveyance, an image scanning device, such as a Charge Coupled Device (CCD) in the scanning stage 901, scans an image of the original while the original passes a scanning position on the platen glass.

In the conventional sheet conveying apparatus, a conveying path from the original tray 906 to the discharge tray 907 through the scanning position is formed by one outer guide surface and one inner guide surface having a lateral U-letter shape. For example, the outer guide surface is formed by a frame of the original cover 902. The inner guide surface is formed by a paper guide mechanism located inside the original cover 902.

And metal plates fixed by screws are arranged on both sides of the paper guide mechanism. A bearing is fitted into a hole formed in the metal plate, and a conveying roller shaft on which a conveying roller made of silicone rubber is fixed is suitably provided. Thus, the conveying rollers are disposed at a prescribed position of the conveying path, and the original is conveyed through the conveying path by the rotation of each conveying roller.

Further, in the original cover 902, one metal pinion stud is fixed to the metal plate between the two metal brackets by caulking. A power drive gear is axially supported by the gear stud. Further, a driving device including a motor that applies power to a power driving gear is provided on the original cover 902. Power is transmitted from the motor of the driving device to the transfer roller shaft. According to the conventional sheet conveying apparatus described above, although the rigidity is high, the weight is increased. In addition, the number of components constituting the paper guide mechanism, the driving device, and the like is large, and the assembly process is complicated. Therefore, such a sheet conveying apparatus is costly and maintenance work is troublesome.

Therefore, there has been proposed a sheet conveying apparatus in which a sheet guide mechanism, which is a guide surface of a horizontal letter U-shaped conveying path, is integrally formed with a frame made of resin such as plastic. Thus, the number of components such as the paper guide mechanism and the number of assembly processes can be reduced, and the cost of the paper conveying apparatus can be reduced.

However, since the sheet is conveyed while sliding on the guide surface of the paper guide, static electricity is generated due to friction between the sheet and the paper guide, and the static electricity is accumulated on the sheet. There are cases where the conveyed sheet is skewed or the conveying speed is unstable due to adhesion to a paper guide or the like, and the quality of the scanned image deteriorates. The generation of static electricity is more pronounced if the paper guide is made of resin.

Recently, scanners, facsimiles, copiers, and the like are required to be smaller in size and more economical. In addition, the sheet conveying apparatus mounted on these machines is also required to be smaller in size and more economical. Therefore, reduction in the number of components and simplification of the assembly process are more required.

In addition, in scanners, facsimiles, copiers, and the like, resource recycling and the like are also important. This requires that each component of the sheet conveying apparatus be disassembled from different kinds of materials, such as metal and plastic, and then reused or disposed of. Therefore, not only the assembly process but also the disassembly process performed when handling these members is preferably simplified.

Disclosure of Invention

The present invention has been developed in view of the above disadvantages. An object of the present invention is to provide a sheet conveying apparatus which can reduce cost and size by a simple structure and is easier to disassemble when handling the apparatus.

In order to achieve the above object, the present invention provides a sheet conveying apparatus which feeds an original to a U-shaped conveying path from an original tray on which a stack of originals is stacked by a sheet feeding member, scans the original conveyed by a conveying member at a scanning position, and then discharges the original onto a sheet discharge tray, characterized in that a paper guide frame forming an inner guide surface of the conveying path, a plurality of side frames on which shafts of the conveying member disposed in the conveying path for conveying the original can be mounted, and a power drive gear are integrally formed of resin, the shafts being disposed upright on the side frames and transmitting rotation of a power source to the shafts of the conveying member.

According to the present invention, the sheet conveying apparatus includes a paper guide frame, side frames, and a gear shaft of a power driving gear, which are integrally formed of plastic. The paper guide frame is an inner guide surface of the U-shaped original document conveying channel. The side frame includes a roller shaft bearing housing having a roller disposed in a conveyance path for conveying a sheet. The gear shaft of the power driving gear is vertically arranged on the side frame and transmits the rotation of the power source to the roller shaft. Further, the rollers for conveying the sheet include a conveying roller for conveying the sheet through the conveying path, and a sheet supply roller for supplying the sheet from the original document tray to the conveying path.

One end of the gear shaft is fitted into a support hole of a bracket that supports the power source in such a manner that a gap exists between the end of the gear shaft and the support hole. Thereby supporting the gear shaft. A charge eliminating guide plate made of a conductive member is disposed on the sheet guide. The charge eliminating guide constitutes a guide surface downstream of the turn portion of the conveying passage having the shape of the lateral letter U. An elastic film is provided on an outer guide surface of the conveying passage having a shape of a lateral letter U at a position facing the charge eliminating guide plate. The elastic film guides the conveyed sheet so that the sheet comes into contact with the charge eliminating guide. The paper guide frame, the side frames and the gear shaft of the power drive gear are integrally formed. So that the process of assembling the side frames to the paper guide frame and the process of assembling the gear shafts to the side frames are not required. Therefore, the number of components and the number of assembly processes of the sheet conveying apparatus can be reduced in comparison with the conventional sheet conveying apparatus, and the cost of the sheet conveying apparatus can also be reduced.

Drawings

Fig. 1 is a cross-sectional view showing a configuration of an upper portion of a copy-and-fax multi-function peripheral 100 according to an embodiment of the present invention.

Fig. 2 is an enlarged cross-sectional view showing a configuration in the vicinity of the sheet conveying apparatus 1.

Fig. 3 is an exploded oblique view showing a combination of the guide frame 102a and the paper guide mechanism 3.

Fig. 4 is an exploded oblique view showing the configuration of the paper guide mechanism 3.

Fig. 5 is a longitudinal sectional view showing the configuration of the paper guide mechanism 3.

Fig. 6A is an enlarged cross-sectional view showing a state in which the engagement portion 312 of the pinion stud 311 is fitted into the support hole 330 of the bracket 33 in such a manner that there is a gap between the engagement portion 312 and the support hole 330. FIG. 6B is an enlarged transverse cross-sectional view showing the gear stud 311 tilted and supported by the support hole 330.

Fig. 7 is a plan view of the guide frame 102 a.

Fig. 8A shows a state where the conveyed original collides against the upper elastic film 36. Fig. 8B shows a case where the downstream side of the elastic membrane 36 is elastically deformed. Fig. 8C shows the case where the elastic film 36 has returned to an initial state for guiding the original to a charge eliminating guide 32.

Fig. 9 is an oblique view showing the appearance of the copy-and-fax multifunction peripheral 900.

Detailed Description

Fig. 1 is a cross-sectional view showing a configuration of an upper part of a copying-and-faxing multifunction peripheral 100 having a sheet conveying device 1 according to an embodiment of the present invention. As shown in the drawing, the copy-and-fax multifunction peripheral 100 includes a scanner table 101 and an original cover 102. A document to be scanned is placed on a platen glass 10 located on the upper surface of a scanning table 101. The original cover 102 can be opened or closed to cover the platen glass 10. Although not shown in the drawings, the copy-and-fax multi-function peripheral 100 further includes an operation panel for inputting a document scanning start signal or the like, an image recording device for recording an image on a recording sheet, a conveying device for electrically conveying the image, and a sheet feed cassette or the like accommodating the recording sheet for recording a scanned image. Well-known structures are exemplary and optional.

A sheet conveying apparatus 1 is disposed as an original auto feeder (ADF) in an original platen 102. The sheet conveying apparatus 1 successively feeds originals to one scanning position P on the platen glass 10. The original is fed from the original tray 2 into one conveying path by the sheet conveying apparatus 1. The original is conveyed down to a scanning position P along a paper guide 3 while being turned upside down to make a U-turn. When the original passes through the scanning position P, an image of the original is scanned by one scanning device 11. Then, the original is discharged onto a discharge tray 4 located below the original tray 2.

Further, the original conveyed by the sheet conveying apparatus 1 may be standard sheets of various sizes commonly used in copiers and printers. Alternatively, the original may be a sheet having a thickness that can pass through the conveyance path and that can be bent along the conveyance path having a shape of the lateral letter U.

The scanning device 11 is located within the scanning table 101. The scanning device 11 includes a light source 12 for irradiating light to a scanning position P, a plurality of mirrors 13 for guiding the reflected light R from the original to a predetermined direction, a condenser lens 14 for focusing the reflected light R, and a Charge Coupled Device (CCD)15 for converting the condensed light into an electric signal and outputting the electric signal. That is, the scanning device 11 is a CCD scanning device with a simplified optical system.

An image of the original conveyed through the conveyance path is scanned at the scanning position P with the scanner 11. The reflected light R from the original is guided to the CCD 15 and forms an image. After an analog/digital conversion and a masking process and the like are performed, an image signal converted into an electronic signal is recorded on a recording paper by an image recording apparatus such as a printer, and the image signal is electrically transmitted by a transmission apparatus such as a codec.

Fig. 2 is an enlarged cross-sectional view showing a configuration in the vicinity of the sheet conveying apparatus 1. As shown in the drawing, the sheet conveying apparatus 1 includes an original document tray 2, a paper guide mechanism 3, a paper discharge tray 4, a pickup roller 5, a paper feed roller 6, a separation pad 7, and a conveying roller 8. The document tray 2 holds a plurality of documents in a stacked state. The paper guide 3 is located downstream of the document tray 2. The paper discharge tray 4 holds the transported documents in a stacked state. The pickup roller 5 and the paper feed roller 6 feed the original stacked on the original tray 2 into the conveyance path. The separation pad 7 is pressed against the paper feed roller 6. The conveyance roller 8 conveys the original through the conveyance path.

As shown in the drawing, the original holder 2 is slightly inclined in the direction in which the original is fed, at the upper portion of the original cover 102. A plurality of originals are stacked on the upper surface of the original holder 2. When a user places an original on the original holder 2, the original is placed in such a manner that its leading edge is aligned at the downstream end of the original holder 2. Although not shown in the drawings, a movable guide for restricting the position of the original in the width direction and preventing the original from being fed askew is further provided on the original holder 2.

A conveyance path having a shape of a lateral letter U is formed downstream of the original tray 2 and is connected to the sheet discharge tray 4. The paper guide mechanism 3 is disposed inside the original cover 102 to form an inner guide surface of the conveyance path. The cover body 102a and the ADF cover 102b of the original platen 102 form an outer guide surface of the conveying path.

The outer guide surface of the conveyance path may be formed separately in the original cover 102 like a guide plate formed of a curved iron plate or the like. However, in order to reduce the number of components and simplify the assembly process, the cover body 102a and the ADF cover 102b of the original platen 102 and the outer guide plate are preferably integrally formed using plastic. An original guide 9 is further provided above the paper guide 3.

The original guide 9 includes a curved portion 90 and a guide film 91. The curved portion 90 curves upward toward one surface of the sheet feed roller 6. The original fed from the original tray 2 is guided to one of the separation pad holders 70 by the bent portion 90 and the guide film 91. The separation pad 7 is attached to the upper surface of the separation pad holder 70. An inclined surface 70a for guiding the original is formed on the upstream side of the separation pad holder 70. The original guided along the guide film 91 is guided along the inclined surface 70a again to come into contact with the surface of the paper feed roller 6. With the curved portion 90 and the guide film 91 of the original guide 9 and the inclined surface 70a of the separation pad holder 70, several originals stacked on the original tray 2 can be held in a stacked state without sliding into the conveyance path.

When the original is placed on the original tray 2, the leading edge of each original is moved out askew along the curved portion 90 and the inclined surface 70 a. Therefore, originals that are originally in close contact with each other are loosened, so that the originals can be easily separated from the uppermost page. Thus, multiple feeding of the original is prevented. Also, the guide film 91 prevents the original from being pinched at the joint of the original guide 9 and the separation pad holder 70. Therefore, the leading edge of the original can be guided to a predetermined position reliably and smoothly. Further, the separation pad holder 70 and the original guide 9 are not necessarily required over the entire width of the upper surface of the paper guide mechanism 3.

The paper feed roller 6 is disposed above the paper guide mechanism 3. The paper feed roller 6 rotates while coming into contact with the original fed from the original tray 2, and feeds the original to the conveyance path. For example, a roller of silicon or Ethylene Propylene Diene (EPDM) terpolymer is fixed on the metal roller shaft 60 to form the sheet feeding roller 6. The roller shaft 60 is rotatably supported on the paper guide 3 by a bearing or the like. A structure in which the paper guide mechanism 3 supports the roller shaft 60 will be described later.

The pickup roller 5 is disposed upstream of the sheet feeding roller 6. The pickup roller 5 feeds the uppermost one sheet of the originals stacked on the original tray 2. In the same manner as the paper feed roller 6, the pickup roller 5 also rotates while coming into contact with the original, and feeds the original to the conveyance path. The pickup roller 5 is supported by a swing arm 51 which swings up and down by a paper feed clutch (not shown) so that the pickup roller 5 can come into contact with the original guide 9 or move away from the original guide 9. In a general case, for example, when an original is set on the original carriage 2, the pickup roller 5 is set at a position away from the original guide 9 by the swing of the swing arm 51. When the original is fed, the pickup roller 5 is lowered by the swing of the swing arm 51 to be in contact with the uppermost page of the original. Then, the uppermost sheet of the original is fed into the conveyance path by the rotation of the pickup roller 5 and the paper feed roller 6.

A cork plate 92 is attached to the upper surface of the original guide 9 at a position where it can contact the pickup roller 5. Therefore, even when the original stacked on the original tray 2 is left by one page, the original is pressed by the pickup roller 5 and the cork sheet 92 and reliably fed into the conveying passage. Further, the pickup roller 5 may be lowered until it comes into contact with the original guide 9. Therefore, even when the thickness of a stack of originals varies depending on the number of original pages, the pickup roller 5 can always be in contact with the uppermost one. The paper-present or paper-absent state of the original on the original carriage 2 is detected by an original set sensor (not shown). Based on the detected signals, a control unit controls the operations of the pickup roller 5, the swing arm 51, and the sheet feed roller 6.

Meanwhile, the separation pad 7 is located below the sheet feeding roller 6. The friction coefficient between the separation pad 7 and the original is smaller than the friction coefficient between the paper feed roller 6 and the original and larger than the friction coefficient between the original. The separation pad 7 is made of, for example, a polyurethane resin.

Such a separation pad 7 is attached to the upper surface of the separation pad holder 70. The separation pad holder 70 is swingably locked at a prescribed position of the paper guide mechanism 3. In addition, the separation pad holder 70 is urged upward by a coil spring 71. Therefore, the separation pad 7 abuts against the surface of the paper feed roller 6 and can swing downward in accordance with the thickness of the original passing through the contact portion. Although the detailed part is not shown in the drawings, the separation pad 7 is not necessarily provided over the entire axial range of the sheet feed roller 6. If the separating pad 7 is used to generate a frictional force sufficient to separate the original, the separating pad 7 may be provided only at a portion where the original of various specifications from the minimum scanning width to the maximum scanning width normally passes.

In the conveying path having a shape of a lateral letter U, a plurality of conveying rollers 8 for conveying the original are arranged at a position immediately downstream of the turning portion (U-turn portion) and a position located most downstream of the conveying path, respectively. The torque of the power source such as the motor is transmitted to the plurality of roller shafts 80 and rotates the plurality of conveying rollers 8. The plurality of rollers 80 are also supported freely rotatably above the paper guide 3. The driven roller 81 that rotates with the rotation of the conveying roller 8 is disposed at a position facing the conveying roller 8 to sandwich the conveying passage. The original is sandwiched by the conveyance roller 8 and the driven roller 81 and conveyed. In addition, the above arrangement of the conveying roller 8 is only an example. The number of the conveying rollers 8 may be increased or decreased as appropriate depending on the shape or distance of the conveying passage.

Hereinafter, the structure of the paper guide mechanism 3 will be described with reference to fig. 2 to 6. As shown in fig. 3, the paper guide mechanism 3 is provided with a pickup roller 5, a paper feed roller 6, a separation pad 7, and a conveying roller 8. In addition, a drive gear (not shown) and the like are mounted on the paper guide 3. The paper guide mechanism 3 is disposed on the cover 102a of the original cover 102. Although not shown in the drawings, the ADF cover 102b is placed openably and closably on the cover 102a on which the paper guide mechanism 3 is mounted.

As shown in fig. 4, the paper guide mechanism 3 is composed of a paper guide frame 30 and a side frame 31 integrally made of plastic, and a charge eliminating guide plate 32. The paper guide 30 constitutes a conveying path having a shape of a lateral letter U. Side frames 31 are provided on both sides of the paper guide frame 30. The charge eliminating guide 32 is located at a position downstream of the turning portion of the sheet guide 30. The plastic material for manufacturing the paper guide 30 and the side frame 31 is a synthetic resin that can be integrally formed by a mold. For example, Acrylonitrile Butadiene Styrene (ABS), high impact polystyrene, or ABS or high impact polystyrene to which a reinforcing material such as glass fiber is added may be used as the plastic for manufacturing the paper guide 30 and the side frames 31.

The paper guide 30 includes a guide surface 300 whose upstream end of the upper surface is inclined in the same manner as the document tray 2 and whose downstream end is curved downward. The guide surface 300 constitutes an inner guide surface located upstream of the turn portion of the conveying channel having a transverse U-shape. The paper feed ribs 301 are arranged in a row in the width direction of the curved portion of the guide surface 300. The paper feed rib 301 reduces the contact surface between the guide surface 300 and the document making a U-turn when the document slides on the guide surface 300. Therefore, the friction force applied to the original is reduced. Since the paper guide 30 and the side frames 31 are integrally formed, the paper guide 30 and the side frames 31 must be formed in such a shape that they can be removed from the mold. Therefore, as shown in fig. 5, at a position where the guide surface 300 becomes vertical, a downstream side of the guide surface 300 is formed so that the dies forming the paper guide 30 and the side frame 31 can be easily removed downward.

On the downstream side of the guide surface 300, a claw-like sheet feeding rib 302 is formed, which protrudes downward from the downstream side. The outer peripheral surface of the paper feed rib 302 and the guide surface 300 are the same surface. The paper feed rib 302 is bent from the turn portion toward the downstream side. By providing a downstream side of the guide surface 300 at a vertical position of the guide surface 300 as described above and a sheet feeding rib 302 projecting downward from the downstream side of the guide surface 300, the sheet guide frame 30 can be formed in a shape such that it can be easily removed from the mold. The original conveyed along the guide surface 300 is guided to the upstream side of the conveying roller 8 and the charge eliminating guide 32. As shown in fig. 4 and 5, a concave portion 303 is formed at the center in the width direction of the guide surface 300. The concave portion 303 locks or engages the separation pad holder 70 and the document guide 9.

The side frames 31 are plate-shaped integrally formed on both sides of the paper guide 30. Through the two side frames 31, through-holes 310 are formed, which serve as bearings for the rollers 60 of the feed rollers 6 and the rollers 80 of the conveying rollers 8. The plurality of through holes 310 are a bearing for each of the roller shafts 60 and 80, and the sheet feeding roller 6 and the conveying roller 8 are supported at prescribed positions with respect to the sheet guide frame 30.

Although not shown in the drawings, each of the rollers 60 and 80 is rotatably inserted through each pair of the through holes 310 of the side frame 31. The drive gear for each roller shaft 60 and 80 is located outside the side frame 31. The rotation of the motor is transmitted to the drive gear, rotating each of the roller shafts 60 and 80. A power drive gear to which power is transmitted from the motor is also axially supported by the side frame 31.

In detail, as shown in fig. 4, a driving gear of each of the rollers 60 and 80 is provided on the outer side of the side frame 31 placed toward the front of the drawing. A gear stud (gear shaft) 311 axially supporting the power drive gear is disposed in a vertical manner on the side frame 31. There are four gear studs 311 at prescribed positions of the side frame 31, and they project outward in the horizontal direction. Each of the gear studs 311 is also integrally formed of plastic with the paper guide frame 30 and side frame 31. The position of the gear stud 311 is set as appropriate depending on the positions of the rollers 60 and 80, the position of the motor, the diameter of the gear, or the like, and is not fixed.

As described above, the paper guide 30, the side frame 31, the through hole 310, and the pinion stud 311 are integrally formed. Therefore, the assembling process of the side frame 31 to the paper guide 30 and the assembling process of the pinion bolt 311 to the side frame 31 are not required. Thereby, the number of parts and the number of assembling steps can be reduced.

The diameter of the end of each gear stud 311 narrows to form a mesh portion 312. Each of the engaging portions 312 is fitted into each of the support holes 330 of the bracket 33 supporting a motor (power source) (not shown) in such a manner that a gap exists between each of the engaging portions 312 and each of the support holes 330. In detail, the bracket 33 is an iron plate which applies a torque to the power driving gear and supports a motor which rotates each of the roller shafts 60 and 80. The motor is fixed to the bracket 33 by a screw clamp or the like. The structure of the bracket 33 for supporting the motor will not be described in detail.

A plurality of support studs 313 are arranged vertically at prescribed positions on the side frame 31 on which a plurality of pinion studs 311 are arranged vertically. The support studs 313 fix the brackets 33 to the side frames 31 at predetermined intervals. A screw hole is formed on the end of each support stud 313. A number of through holes 331 are formed through the bracket 33 according to the position of each support stud 313. The bracket 33 is fixed to the side frame 31 by inserting a plurality of screws 34 through the through holes 331 and screwing them into the screw holes of each support stud 313.

Each support stud 313 is also integrally formed with the paper guide frame 30 and the side frame 31 in the same manner as the above-described gear stud 311. In order to reinforce each support stud 313, a reinforcing rib 314 is integrally formed on the side frame 31 so as to be connected to each support stud 313. As described above, the support holes 330 are formed through the brackets 33 fixed to the side frames 31, where the engaging portions 312 of each of the gear studs 311 can be fitted in such a manner that a gap exists between each of the support holes 330 and each of the engaging portions 312. As shown in fig. 6A, the engaging portion 312 of each of the gear studs 311 is fitted into the support hole 330 in such a manner that a gap exists between the engaging portion 312 and the support hole 330. So that an external force is applied to the pinion stud 311 integrally formed with the side frame 31 or the like from plastic. As shown in fig. 6B, when the gear stud 311 is in the inclined state, the meshing portion 312 is supported by the support hole 330 and the inclination of the gear stud 311 is restricted. Therefore, the pinion stud 311 is reinforced and can be prevented from being damaged.

As shown in fig. 4 and 5, the charge eliminating guide 32 located downstream of the turning portion of the paper guide 30 is formed of a curved or bent conductive member such as a metal plate. The lower surface 320 of the charge-eliminating conductive plate 32 forms an inner guide surface downstream of the turn portion of the transfer channel having the shape of the lateral letter U. On both sides of the downstream side of the charge eliminating guide 32, projections 321 are formed vertically upward from the lower surface 320. A through hole 322 is formed through each protrusion 321. The roller shaft 80 of the conveying roller 8 is inserted through the through hole 322 of the projection 321, and the roller shaft 80 is supported by the through hole 310 of the side frame 31. Thus, the charge eliminating guide 32 is swingably arranged between the side frames 31. Further, at prescribed positions on both sides of the charge eliminating guide 32, a protrusion 323 is formed vertically upward from the lower surface 320. An elongated hole 324 is formed through each protrusion 323.

A screw is inserted through each of the long holes 324 of the protrusion 323, and the charge eliminating guide plate 32 is screwed to the side frame 31. Therefore, the swing of the charge eliminating guide 32 is limited within the range of the long hole 324. As shown in fig. 2, the coil spring 35 pushes the charge eliminating guide plate 32 fitted like the paper guide mechanism 3 downward. The charge eliminating guide 32 can swing upward within a fixed range according to the reaction force of the original passing through the conveyance path, or the like. When the conveyed original comes into contact with the charge eliminating guide 32, static electricity generated on the original due to friction with the paper guide 30 can be eliminated.

It can be assumed that the frictional force between the original and the paper guide 30 is the largest at the turn portion where the original makes a U-turn. Therefore, the charge eliminating guide 32 is arranged just downstream of the turning portion. So that static electricity generated due to friction with the paper guide frame 30 can be effectively eliminated. By mounting the charge-eliminating guide 32 on the shaft of the conveying roller 8, when separating plastic and metal materials for recycling, the charge-eliminating guide 32 can be easily removed from the side frame 31 by removing the shaft of the conveying roller 8 from the side frame 31. Therefore, the process of detaching the paper guide mechanism 3 at the time of recycling is easy. In addition, in order to quickly eliminate the static electricity transferred to the charge eliminating guide 32, the charge eliminating guide 32 is preferably electrically connected and grounded together with a conductive member of the frame or the like of the sheet conveying apparatus 1.

The cover 102a of the original cover 102 is also integrally formed of synthetic resin by a mold, and is formed in the same manner as the paper guide 30 and the side frame 31. For example, ABS, high impact polystyrene, or ABS or high impact polystyrene to which a reinforcing material such as glass fiber is added may be used. As shown in fig. 2 and 7, an opening 20 is formed in the housing 102a to which the paper guide 3 is to be mounted. The original conveyed along the paper guide 30 passes through a scanning position P on the platen glass 10 at the opening 20, and an image of the original is scanned by the scanner 11.

As shown in fig. 7, the guide surfaces 21 and 22 are formed obliquely upward from the opening 20 on the upstream side and the downstream side of the opening 20, respectively. The guide surfaces 21 and 22 are located downstream of the turn of the conveying channel having the shape of the transverse letter U. The guide surfaces 21 and 22 form outer guide surfaces upstream and downstream of the scanning position P. Paper feed ribs 23 and 24 are also arranged in the width direction of the guide surfaces 21 and 22, respectively, to reduce the frictional force between the guide surfaces 21 and 22 and the original when the conveyed original slides on the guide surfaces 21 and 22.

On the downstream side edges of the guide surfaces 21 and 22, three cutouts or two cutouts 21a, 22a are formed in the width direction thereof, respectively. The driven roller 81 facing the conveying roller 8 is placed in the cutouts 21a and 22 a. As described above, the guide surfaces 21 and 22 forming the conveying passage and the cover body 102a of the original cover 102 are integrally formed. Therefore, an assembling process of assembling the guide member to the cover 102 is not required, and the number of parts and the number of assembling steps can be reduced.

As shown in fig. 2, an elastic film 36 is provided on the guide surface 22 of the original cover 102 a. In detail, as shown in the drawing, an upstream end of the elastic membrane 36 is fixed to an upstream side of the guide surface 22. A part of the elastic membrane 36 downstream of the fixed portion is not fixed to the guide surface 22 and protrudes diagonally upward in an elastically deformable manner. The downstream end of the flexible membrane 36 is disposed in contact with the lower surface 320 of the charge-eliminating conductive plate 32.

With the elastic film 36 arranged in the above-described manner, downstream of the scanning position P, the vertical width of the conveyance path formed by the lower surface 320 of the charge-eliminating guide plate 32 and the guide surface 22 gradually narrows toward the lower surface 320 of the charge-eliminating guide plate 32. The elastic film 36 has an appropriate strength to guide the conveyed original to be in contact with the charge eliminating guide 32. Meanwhile, the elastic film is a thin film that can be elastically deformed to the guide surface 22 by contact with the conveyed original. For example, the elastic film 36 may be a synthetic resin film or the like, such as polypropylene.

As shown in fig. 8A, when the conveyed original touches the elastic film 36, the elastic film 36 is pushed by the original. Then, as shown in fig. 8B, the downstream end of the elastic membrane 36 is elastically deformed to approach the guide surface 22. Thus, when the original is re-conveyed, as shown in fig. 8C, the elastic film 36 is restored to the original state and guides the original to the charge eliminating guide 32.

Therefore, the conveyed original reliably contacts the charge eliminating guide 32, and static electricity of the original is eliminated. As described above, when the original touches the elastic film 36, the elastic film 36 is elastically deformed. Thus, an extra load is not applied to the original. In addition, the influence on the original conveying speed or the conveying direction is small, and the deterioration of the scanned image quality is also minimal. Also, it is not necessary that the entire width direction of the charge-eliminating guide plate 32 be covered with the elastic film 36. Even when the elastic film 36 is formed in the entire width direction according to the required elastic force, the elastic force can be adjusted by forming a slit in the elastic film 36 or forming the elastic film 36 only as a pair near the center portion or at both the left and right ends of the charge eliminating guide 32.

When the smoothness of the sheet conveyance between the charge-eliminating guide plate 32 and the elastic film 36 is most prioritized, a slight gap of approximately one standard sheet thickness may be formed between the downstream end of the elastic film 36 and the lower surface 320 of the charge-eliminating guide plate 32 without the downstream end of the elastic film 36 and the lower surface 320 of the charge-eliminating guide plate 32 contacting.

The structure of the sheet conveying device 1 and the copy-and-fax multifunction peripheral 100 described in the present embodiment is only an example. The configuration of the sheet conveying apparatus 1 and the copy-and-fax multi-function peripheral 100 can be appropriately changed without departing from the gist of the present invention. For example, the scanning device may be provided specifically rather than in combination with a flatbed scanner. A Contact Image Sensor (CIS) may be used instead of the scanning device in the simplified optical system using the CCD. In addition, there may be a CCD or a CIS, respectively, at the opposite position of the transfer channel. Alternatively, the conveyance path having the shape of the lateral letter U may also have an original return path, and both sides of the original may be scanned.

Claims (4)

1. A sheet conveying apparatus that feeds an original on an original tray to a conveying path with a sheet feeding member disposed near an entrance of the conveying path, conveys the original to a scanning position with a conveying member disposed in the conveying path, and then discharges the original onto a sheet discharge tray with a sheet discharge member disposed near an exit of the conveying path, comprising:

a guide plate placed on the guide surface inclined upward toward the downstream side from the scanning position is inclined toward the diagonally downstream side from one guide surface to the other guide surface, and a free end of the guide plate can be elastically inclined toward the guide surface.

2. The sheet conveying apparatus according to claim 1, wherein the inner guide surface inclined upward from the scanning position is a charge eliminating guide plate, and the outer guide surface is the guide plate that can be inclined downward.

3. The sheet conveying apparatus according to claim 1, wherein the resiliently tiltable free end of the guide plate is disposed in close contact with the charge eliminating guide plate, which is the other guide surface.

4. The sheet conveying apparatus according to claim 1, wherein the resiliently tiltable free end of the guide plate is held with a gap from the charge eliminating guide plate, which is the other guide surface.