JP2010030718A - Document conveying device and image forming device having the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a document conveying device capable of stably and smoothly conveying a document by suppressing the deflection and oscillation of the document while preventing defects such as the noise resulting from the contact of the document on a conveying guide and the wear of the conveying guide and the document from occurring immediately on the downstream side of a document reading part. <P>SOLUTION: This document conveying device 20 includes the document reading part 33 for reading the images of the document by passing through over the contact glass 71 of an image reading device 70 and a pair of conveyor rollers 42 provided on the downstream side of a tilted conveying guide 72 for guiding the document passing through the document reading part 33 into the document conveying device 20. A driven roller 55 which is a rotating body abutting on the document and rotating when the document is conveyed is installed at a position on the downstream side of the tilted conveying guide 72, on the upstream side of the pair of conveying rollers 42, and above a document conveying passage. Consequently, the document is prevented from being rubbed forcibly against a projection such as the conveying guide, and the frictional resistance while the document is conveyed is reduced by rotating the driven roller 55. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a document conveying apparatus applicable to an image forming apparatus typified by a copying machine or a printer. The present invention also relates to an image forming apparatus equipped with the document conveying device.

  Some image forming apparatuses such as copying machines and facsimiles include a document conveying device that automatically sends a plurality of documents to a document reading unit. The document conveying device separates the documents one by one from the uppermost layer of the document stack stacked on the document loading tray, and sends the document toward the document reading unit. The original is read by the original reading unit and then discharged onto a document discharge tray provided on the most downstream side of the original conveyance path.

  When the original passes through the contact glass of the image reading apparatus at the position of the original reading section in the middle of the conveyance, the image drawn on the surface of the original is read by the image reading apparatus. Therefore, at the position of the document reading section, it is necessary to pass the document while maintaining a suitable conveyance state and contacting the contact glass. An example of a document conveying device that improves the document reading performance in the document reading unit as described above can be seen in Patent Document 1. In the document conveying device described in Patent Document 1, a conveyance guide (inclined conveyance guide) that guides a document that has passed through a position of a document reading unit to a conveyance roller after reading downstream of the document reading unit is provided immediately downstream of the contact glass of the image reading device. Prepared on the side. By devising the inclination angle of the conveyance guide, the impact generated at the leading edge of the document is reduced, and stable document conveyance is realized.

However, with this conventional configuration, there is a concern that the document may be bent at the position of the conveyance guide and the conveyance path may change. In particular, the downstream side of the conveyance guide is also a place where the document once exited from the document conveyance device for image reading returns to the inside, so the upper guide member and the lower guide member of the document conveyance path The interval is relatively wide. Therefore, the document is more likely to bend and vibrate at that location, and the document conveyance may become unstable. In view of this, an original conveying apparatus that solves such problems and obtains an appropriate reading performance of an image has been proposed. The document conveying device described in Patent Document 2 includes a protrusion at a location downstream of the document reading unit and facing the conveyance guide (inclined conveyance guide).
JP 2004-37959 A (page 8, FIG. 8) JP 2006-86957 A (6th page, FIG. 2)

  In the document conveying device described in Patent Document 2, a projection is provided at a position facing the conveyance guide, so that the document is conveyed while maintaining a state in which the document abuts on the projection and bulges downward. This prevents a change in the transport path. However, with this configuration, the document is forcibly rubbed against the protrusions in order to stabilize the document transport path. This may increase the frictional resistance between the document and the protrusion. Further, when the document being conveyed reaches the position of the protrusion, the leading edge of the document may hit the protrusion, and the leading edge of the document may be bent. Therefore, there is a possibility that the sound of rubbing the document against the projection, the wear of the projection, the wear / break of the document, the correction error of the oblique feed, and the like may occur.

  The present invention has been made in view of the above points, and at a location immediately downstream in the document transport direction of the document reading unit that reads the image of the document by passing it over the contact glass of the image reading device during the conveyance, Suppresses the deflection and vibration of the document while preventing the occurrence of problems such as noise caused by contact of the document with the conveyance guide such as protrusions, wear of the conveyance guide, wear of the document, oblique feeding, etc., and stable and smooth An object of the present invention is to provide a document conveying device capable of performing document conveyance. It is another object of the present invention to provide a highly reliable image forming apparatus equipped with such a document conveying device.

  In order to solve the above-described problems, the present invention provides an original reading unit that reads an image of an original by passing it over the contact glass of the image reading apparatus in the middle of conveyance, and immediately downstream of the contact glass in the original conveyance direction. In a document conveying apparatus comprising a pair of document conveying rollers provided downstream of an inclined conveyance guide that guides a document that has been placed and passed through a document reading unit to the inside of the upper document conveying apparatus, the document of the inclined conveyance guide A rotating body is provided on the downstream side in the transport direction and on the upstream side of the pair of document transport rollers and above the document transport path so as to contact the document and rotate according to the transport of the document.

  In the document conveying device having the above-described configuration, the rotating body has a lower end portion of the upper guide member that protrudes most toward the image reading device between the document reading unit and the rotating body, and the document conveying device. It is positioned below the straight line connecting the nip of the roller pair and extending along the document conveying direction.

  In the present invention, the document conveying device is mounted on the image forming apparatus.

  According to the configuration of the present invention, an original reading unit that reads an image of an original by passing it over the contact glass of the image reading device in the middle of conveyance, and the document reading unit disposed immediately downstream of the contact glass in the original conveyance direction. A document transport roller pair provided on the downstream side of the inclined transport guide that guides the document that has passed through the upper portion of the document transport apparatus to the downstream side of the tilt transport guide in the document transport direction, In addition, a rotating body that contacts the document and rotates in accordance with the conveyance of the document is provided upstream of the document conveyance roller pair and above the document conveyance path. Without rubbing, the distance between the document transport paths in the vertical direction can be reduced as much as possible to stabilize the document transport path. Frictional resistance can be reduced. As a result, it is possible to prevent the occurrence of adverse effects caused by the friction between the document and the conveyance guide such as a protrusion. Therefore, at the location immediately downstream of the document reading unit in the document transport direction, it is possible to prevent the occurrence of problems such as noise, wear of the transport guide, wear of the document, oblique feed, etc. Thus, it is possible to provide a document transport device capable of performing smooth document transport.

  In addition, the rotating body has a lower end portion of the upper guide member that protrudes most toward the image reading device between the document reading unit and the rotating body, and a nip of the pair of document conveying rollers. Since it is positioned below the straight line extending along the document conveyance direction, the vertical interval of the document conveyance path can be further narrowed, and the document passing through the rotating body is sandwiched between the document conveyance roller pairs. If it is made, it will become easy to contact a rotary body. In this way, the document conveying path is stabilized, and the action of conveying the document while contacting the rotating body is enhanced. Therefore, at the position immediately downstream of the document reading unit in the document conveyance direction, the effect of suppressing the deflection and vibration of the document is prevented while preventing the occurrence of problems such as noise, conveyance guide wear, document wear, and oblique feeding. Therefore, it is possible to perform more stable and smooth document conveyance.

  In the present invention, since the document conveying device is mounted on the image forming apparatus, the document is immediately conveyed by the document reading unit that reads the image of the document by passing it over the contact glass of the image reading device during the conveyance. Suppresses the deflection and vibration of the document while preventing problems such as noise caused by contact of the document with the conveyance guide such as protrusions, wear of the conveyance guide, wear of the document, oblique feeding, etc. Thus, it is possible to obtain a highly reliable image forming apparatus capable of performing stable and smooth document conveyance.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  First, an image output operation of an image forming apparatus equipped with an original conveying apparatus according to an embodiment of the present invention will be described while explaining the outline of the structure with reference to FIG. FIG. 1 is a schematic vertical sectional front view of an image forming apparatus. In the drawing, a solid line arrow indicates a sheet conveyance path and a conveyance direction, and a one-dot chain line arrow indicates a laser beam L.

  As shown in FIG. 1, a paper feed cassette 3 is disposed below the inside of the main body 2 of the image forming apparatus 1. The paper feed cassette 3 stores and accommodates paper P such as cut paper before printing. The sheets P are separated and sent one by one toward the upper left of the sheet cassette 3 in FIG. The paper feed cassette 3 can be pulled out horizontally from the front side of the main body 2.

  A first paper transport unit 4 is provided inside the main body 2 and to the left of the paper feed cassette 3. The first paper transport unit 4 is formed substantially vertically along the left side surface of the main body 2. Then, the first paper transport unit 4 receives the paper P sent out from the paper feed cassette 3 and transports it to the transfer unit 9 vertically upward along the left side surface of the main body 2.

  A manual paper feed unit 5 is provided above the paper feed cassette 3 at a location on the right side which is the side opposite to the left side of the main body 2 where the first paper transport unit 4 is formed. Yes. In the manual sheet feeder 5, paper P of a size that is not contained in the paper cassette 3, thick paper, and OHP sheets that are to be fed one by one are placed.

  A second paper transport unit 6 is provided on the left side of the manual paper feed unit 5. The second paper transport unit 6 is located immediately above the paper feed cassette 3, extends substantially horizontally from the manual paper feed unit 5 to the first paper transport unit 4, and joins the first paper transport unit 4. Then, the second paper transport unit 6 receives the paper P or the like sent from the manual paper feed unit 5 and transports it to the first paper transport unit 4 substantially horizontally.

  On the other hand, an original conveying device 20 is provided on the upper surface of the main body 2 of the image forming apparatus 1, and an image reading device 70 is provided below the original conveying device 20. When a user copies a document, the document carrying device 20 is loaded with a document on which images such as characters, figures, and patterns are drawn. The document conveying device 20 separates the documents one by one and sends them out, and the image reading device 70 reads the image.

  The reading of the document image, that is, the start of printing is executed using an operation panel (not shown) provided on the front side of the image reading apparatus 70 at the upper part of the main body 2. The user can input and set printing conditions such as the paper size to be used, enlargement / reduction, and the presence / absence of double-sided printing from the operation panel.

  The image data of the document is sent to the exposure device 7 disposed above the second paper transport unit 6 and in the center of the main body 2. The exposure device 7 irradiates the image forming unit 8 with laser light L controlled based on the image data.

  An image forming unit 8 and a transfer unit 9 are provided above the first paper transport unit 4 and to the left of the exposure device 7. In the image forming unit 8, an electrostatic latent image of a document image is formed by the laser light L irradiated by the exposure device 7, and a toner image is developed from the electrostatic latent image. The toner is supplied to the image forming unit 8 from a toner container 10 provided above the exposure device 7. The toner image formed by the image forming unit 8 is transferred by the transfer unit 9 to the pre-printing paper P sent in synchronization by the first paper transport unit 4.

  A fixing device 11 is provided above the transfer unit 9. The paper P carrying the unfixed toner image in the transfer unit 9 is sent to the fixing device 11 where the toner image is heated and pressed by a heat roller and a pressure roller to be fixed.

  A paper guide device 12 is provided above the fixing device 11. The paper P discharged from the fixing device 11 is discharged from the paper guiding device 12 to the in-body paper discharge portion 13 provided in the image forming apparatus 1 when double-sided printing is not performed.

  The discharge port portion from which the paper P is discharged from the paper guide device 12 toward the in-body paper discharge portion 13 functions as a switchback portion 14. When performing duplex printing, the switchback unit 14 changes the transport direction of the paper P discharged from the fixing device 11. Then, the paper P passes through the paper guide device 12 and is sent downward through a double-sided printing paper conveyance path 15 provided on the left side of the fixing device 11 and on the left side of the transfer unit 9, and again the first paper conveyance. It is sent to the transfer section 9 via the section 4.

  Next, the outline of the structure of the document conveying device 20 mounted on the upper surface of the main body 2 will be described with reference to FIG. FIG. 2 is a schematic vertical sectional front view of the document feeder. A solid line arrow in the drawing indicates a document conveyance path and a conveyance direction.

  As shown in FIG. 2, the document conveying device 20 includes a document placing tray 21, a lift plate 22, a document feeding unit 30, and a document discharge tray 23.

  The document placing tray 21 is provided on the upper portion of the document conveying device 20. Documents can be stacked on the document placing tray 21 from above. The document placing tray 21 is configured to be inclined downward from upstream to downstream in the document conveying direction, that is, from right to left in FIG.

  The lift plate 22 is provided on the downstream side of the document tray 21 in the document transport direction. The lift plate 22 is composed of a plate-like member having a shape along the placement surface of the document placement tray 21. The lift plate 22 is provided so as to be rotatable in a vertical plane along the document conveying direction with a substantially horizontal support shaft 22a provided at the upstream portion as a center and a downstream end as a free end. The lift plate 22 is rotationally displaced about the support shaft 22a by a drive mechanism (not shown) during document supply, and the downstream end of the document stacked on the document placement tray 21 is disposed above the supply plate. It is urged upward so as to contact the paper portion 60.

  The document feeding unit 30 includes a document supply port 31 and a sheet feeding unit 60 at the downstream end of the document loading tray 21 in the document transport direction. The paper feed unit 60 separates the originals stacked on the original placement tray 21 one by one from the uppermost layer, and supplies the originals toward the inside of the original feeding unit 30 through the original supply port 31. A first document conveyance path 32 extends toward the inside of the document feeding unit 30 on the downstream side of the document supply port 31.

  The tip of the first document conveyance path 32 reaches the bottom surface of the document conveyance device 20, and a document reading unit 33 is provided at this position. Further, following the first document conveyance path 32, a second document conveyance path 34 extends from the position of the document reading unit 33. The document sent to the document reading unit 33 moves further from the first document conveyance path 32 to the second document conveyance path 34, that is, from the left to the right in the position of the document reading unit 33 in FIG. During the process, the image on the first surface, which is the lower surface, is read by the image reading device 70 (see FIG. 1) of the main body 2 provided below the image forming apparatus.

  A document switching unit 35 is provided downstream of the document reading unit 33 in the second document transport path 34. When it is necessary to read both the front and back images of the original, the original that has reached the original switching unit 35 is distributed to the upper side of the second original conveyance path 34. Then, the conveyance direction is changed to the opposite direction by the document reversing unit 36 downstream of the document conveyance direction. The document whose transport direction has been changed passes through the upper side of the document switching unit 35 and is sent to the first document transport path 32 on the upstream side of the document reading unit 33, and the image on the second surface is read again by the document reading unit 33. .

  A document discharge port 37 is provided downstream of the document switching unit 35 and downstream of the second document transport path 34. The document whose image has been read is discharged from the document discharge port 37 to the document discharge tray 23.

  The document discharge tray 23 is provided below the document placement tray 21, and these trays are configured in two upper and lower stages. The document discharged to the document discharge tray 23 can be taken out from the front side of the document conveying device 20.

  The document loading tray 21 and the document discharge tray 23 are opposite to each other in the document transport direction, that is, in FIG. 2, the document loading tray 21 sends the document to the left, and the document discharge tray 23 receives the document. It is configured to discharge toward the right. Thus, the document supply port 31 and the document discharge port 37 are provided on the same side of each tray, that is, on the left side in FIG. 2 with respect to the direction in which the document reading unit 33 exists. The first document transport path 32 and the second document transport path 34 extending from the document supply port 31 to the document discharge port 37 through the document reading unit 33 are formed in a U-shape in the vertical direction as shown in FIG. That is, it is provided in a shape curved in a U shape when viewed from the front.

  With the above configuration, the document conveying device 20 separates the documents stacked on the document placing tray 21 one by one and feeds them into the document feeding unit 30, reads the image by the document reading unit 33, and then discharges the document. It is discharged to the tray 23.

  Next, the detailed configuration of the document feeder 30 of the document feeder 20 will be described with reference to FIG. 3 in addition to FIG. FIG. 3 is a front view of a vertical section showing the document feeding portion of the document conveying device. Note that solid arrows in FIG. 3 indicate the transport path and transport direction of the document.

  As described above, the document feeding unit 30 includes the document supply port 31 and the sheet feeding unit 60 at the downstream end of the document loading tray 21 in the document transport direction (see FIG. 3). As shown in FIG. 3, the first document conveyance path 32 extends downward on the downstream side of the document supply port 31.

  The paper feed unit 60 is provided above a substantially central portion in the document width direction that is perpendicular to the document conveyance direction, and includes a pickup roller 61, a paper feed belt 62, and a separation roller 63.

  The pickup roller 61 is provided immediately downstream of the document supply port 31. At the time of document supply, the downstream portion of the document stacked on the document placement tray 21 is lifted by the lift plate 22, and the uppermost layer at the downstream end of the document contacts the pickup roller 61 from below. The uppermost layer of the original is transferred to the paper feeding belt 62 by the pickup roller 61 and conveyed to the inside of the original feeding unit 30 by the paper feeding belt 62.

  The sheet feeding belt 62 is arranged on the downstream side of the pickup roller 61 so that the lower part of the surface projects into the first document conveyance path 32. Further, the paper feeding belt 62 is wound around two pulleys and rotates clockwise so that the original can be conveyed to the left from the original supply port 31 in FIG. The separation roller 63 is disposed below the paper feed belt 62 and is in contact with the paper feed belt 62. The document is inserted through a conveyance nip formed by the contact between the sheet feeding belt 62 and the separation roller 63.

  When a plurality of originals enter a conveyance nip formed by contact between the paper feed belt 62 and the separation roller 63, only the upper upper original that is overlapped is sent out by the paper feed belt 62. Due to the action of the separation roller 63, the overlapped lower document is not sent out, so that it is possible to prevent the problem of double feeding that the document is fed in a superimposed manner.

  On the first document conveyance path 32, a registration roller pair 38 and conveyance roller pairs 39 and 40 are provided downstream of the location of the paper feed unit 60. The registration roller pair 38 is composed of a registration roller 38a and a roller 38b that are in pressure contact with each other. The registration roller pair 38 corrects the oblique feed so that accurate reading can be performed on the document going to the document reading unit 33, and suitable timing. Measure and send out.

  A document reading unit 33 is provided downstream of the conveyance roller pair 40. Here, the first document conveyance path 32 extending from the document supply port 31 passes through the paper feeding unit 60, the registration roller pair 38, and the conveyance roller pairs 39 and 40 to the position of the document reading unit 33, and is counterclockwise when viewed from the front. Curved to rotate in the direction. Accordingly, the first document conveyance path 32 extends toward the left and below in FIG. 3 on the upstream side of the document reading unit 33, and the second document conveyance path 34 extending continuously from the first document conveyance path 32 is the document reading. On the downstream side of the portion 33, it extends obliquely upward to the right to the document discharge port 37 and the document discharge tray 23.

  The document reading unit 33 includes a reading guide member 41. The reading guide member 41 is arranged to face the contact glass 71 of the image reading device 70 of the main body 2 provided below the document reading unit 33. The reading guide member 41 extends long in the document width direction, that is, in the front-rear direction of the document conveying device 20, and has a shape in which a portion for guiding the document protrudes downward. In the closed state of the document conveying device 20 with respect to the image reading device 70, the reading guide member 41 is below the reading guide member 41, so that the document conveyed between the contact glass 71 and the contact glass 71 comes into contact with the contact glass 71. I am guiding you.

  The document sent to the document reading unit 33 moves from the first document transport path 32 to the second document transport path 34, and moves from the left to the right in the lower part of the reading guide member 41 in FIG. An image is read by a reading unit (not shown) disposed below the contact glass 71 while passing through the contact glass 71.

  A conveyance roller pair 42 and a document switching unit 35 are provided on the second document conveyance path 34 on the downstream side of the document reading unit 33. The document switching unit 35 is provided with a switching guide 43 that can swing in a vertical plane about a support shaft (not shown) that extends substantially horizontally in the front-rear direction. The switching guide 43 extends long in the front-rear direction of the document conveying device 20, that is, in the document width direction, and has a wedge-shaped vertical cross-sectional shape viewed from the front of the front end portion on the upstream side in the document conveying direction so that the document can be easily distributed. Yes. Further, the switching guide 43 is driven by a solenoid (not shown) which is a driving device arranged on the back side thereof, and changes its posture so that the leading end portion on the upstream side in the document conveying direction is swung up and down.

  A document discharge port 37 and a document discharge roller pair 44 are provided downstream of the document switching unit 35 and at the downstream end of the second document transport path 34. The document whose image has been read is discharged from the document discharge port 37 to the document discharge tray 23 (see FIG. 2) by the pair of document discharge rollers 44.

  On the other hand, on the downstream side of the document switching section 35, a third document conveyance path 45 extends obliquely upward to the right with respect to the second document conveyance path 34 extending substantially rightward in FIG. When it is necessary to read both the front and back images of the document, the posture of the switching guide 43 of the document switching unit 35 is changed downward, and the document on which the image on the first surface is read by the document reading unit 33 is converted to the second document. The document is fed from the middle of the conveyance path 34 to the document reversing unit 36 through the third document conveyance path 45.

  A first document branching unit 46 is provided downstream of the document switching unit 35 in the third document transport path 45. The first document branching portion 46 is provided at the document discharge tray 23 side with respect to the third document transport path 45 and is branched to a fifth document transport path 53 (described later). A first branch guide 47 is provided between the five document transport paths 53.

  The first branch guide 47 extends long in the front-rear direction (document width direction) of the document conveying device 20, and has a wedge-shaped vertical sectional shape when viewed from the front end of the downstream end of the third document conveying path 45, that is, the upper end. There is no. Further, the lower portion of the first branch guide 47 is supported by being connected to the frame of the document conveying device 20 by a spring material (not shown), and the upper end of the first branch guide 47 is centered around the support portion in the vertical direction along the document conveying direction. It can swing in the plane.

  The first branch guide 47 is arranged so that the upper end side of the first branch guide 47 closes the third document conveyance path 45. Further, the spring material that supports the first branch guide 47 has a resilience enough to bend when the original comes into contact with the first branch guide 47. Thereby, when the document passes through the third document transport path 45, the first branch guide 47 changes the posture so that the downstream end portion, that is, the upper end portion is swung to the right in FIG. When the document has passed through the first branch guide 47 or when the document is not in contact, the first branch guide 47 swings the upper end to the left, and the posture shown in FIG. 3 Holds a posture to block the document conveyance path 45.

  A second document branching section 48 is provided at the downstream end of the third document transport path 45 and between the document reversing section 36. The second document branch section 48 is provided with a second branch guide 49. The second branch guide 49 extends long in the front-rear direction (document width direction) of the document conveying device 20, and has a vertical cross-sectional shape as viewed from the front end of the downstream end of the third document conveying path 45, that is, the right end in FIG. It has a wedge shape. Further, the second branch guide 49 has a support shaft (not shown) extending in the front-rear direction substantially horizontally on the left side portion thereof, and swings in a vertical plane along the document conveyance direction with the support shaft as a center. It is possible to move.

  The second branch guide 49 is arranged so that the right end side in FIG. 3 closes the third document conveyance path 45. Further, the second branch guide 49 is formed with a weight that can swing about the center of the support shaft when the original comes into contact with the right end of the second branch guide 49. Thereby, when the document passes through the third document transport path 45, the second branch guide 49 changes the posture so that the downstream end, that is, the right end is swung upward in FIG. Then, when the document has passed through the second branch guide 49 or when the document is not in contact, the second branch guide 49 swings the right end portion downward by the action of gravity and a stopper (not shown). 3, that is, a posture that closes the third document conveyance path 45.

  The document reversing unit 36 is disposed downstream of the third document conveyance path 45 and above the downstream portion of the second document conveyance path 34, and includes a reversing roller pair 50 and a reversing tray 51.

  The reversing roller pair 50 is disposed at the uppermost stream portion of the document reversing unit 36 with respect to the third document conveying path 45, and a reversing roller 50 a that forms a conveyance nip to abut each other and convey the document, and a driven roller. 50b. The reverse roller 50a is rotated clockwise and counterclockwise in FIG. 3 by a motor (not shown). The driven roller 50b is in pressure contact with the reverse roller 50a from above. The reversing tray 51 is disposed immediately below the document placing tray 21 with a relatively narrow gap, and extends obliquely upward similarly to the document placing tray 21 (see FIG. 2).

  In the document reversing unit 36, the downstream portion of the document conveyed from the left to the right in FIG. 3 through the third document conveyance path 45 is once sent to the reversing tray 51, and the upstream portion of the document is reversed. When the roller pair 50 is reached, the rotation of the reversing roller 50a is reversed while the document is held in the conveyance nip between the reversing roller 50a and the driven roller 50b, thereby moving the document conveyance direction from right to left. And change.

  In FIG. 3, a fourth document conveyance path 52 is provided on the left side of the document reversing unit 36 and the second document branching unit 48 and above the third document conveyance path 45 and the document reading unit 33. The fourth document conveyance path 52 extends from the position of the document reversing unit 36 and the second document branching unit 48 toward the left in FIG. 3, and beyond that, upstream of the registration roller pair 38 in the first document conveyance path 32. It joins the part of. As a result, the document that has completely passed through the second document branching unit 48 and whose conveyance direction has been changed by the document reversing unit 36 passes through the fourth document conveyance path 52 and again reaches the first document on the upstream side of the document reading unit 33. The image is fed into the conveyance path 32, reaches the document reading unit 33, and the image on the second surface, which is the lower surface, is read.

  In addition to the method of reading the images on both the front and back sides of the document by the document reading unit 33, the second contact image sensor S provided between the conveyance roller pairs 39 and 40 in the first document conveyance path 32 is used for the second. There is also a method of reading a surface image. According to this, when the document passes through the area of the first document conveyance path 32 from the position of the conveyance roller pair 39 to the position of the document reading unit 33, the image on the second surface is first displayed by the contact image sensor S first. The image on the first surface is read by the document reading unit 33. Therefore, it is possible to read the images on both the front and back sides of the document only by transporting the first document transport path 32 and the second document transport path 34 once.

  Then, in the middle of the third document conveyance path 45, the first document branching section 46 on the upstream side of the second document branching section 48, which is a branching section with the fourth document conveyance path 52, exits from the third document conveyance path 45. A fifth document conveyance path 53 is provided so as to be branched. The fifth document conveying path 53 branches from the third document conveying path 45 at the first document branching section 46 and extends downward, and the second document conveying path 34 is downstream of the document switching section 35 having the switching guide 43. Have joined. A conveyance roller pair 54 is provided in the middle of the fifth document conveyance path 53. The fifth document transport path 53 aligns the front and back of the original document stacking tray 21 with the original document that has been read on both front and back images by feeding it back to the document reversing unit 36 and switching it back. Then, the paper is transported in the direction of the document discharge tray 23 in the second document transport path 34 to be discharged to the document discharge tray 23.

  Next, a detailed configuration around the document reading unit 33 of the document feeding unit 30 will be described with reference to FIGS. 4 and 5 in addition to FIG. FIG. 4 is a partially enlarged vertical sectional front view showing the periphery of the document reading portion of the document feeding portion, and FIG. 5 is a partially enlarged vertical sectional front view showing the periphery of the document reading portion similar to FIG. It is. Note that a thick solid line on the document conveyance path in FIG. 5 indicates the document being conveyed.

  As described above, the contact glass 71 of the image reading device 70 is provided at the position of the document reading unit 33 of the document feeding unit 30 so as to face the reading guide member 41. Further, the image reading apparatus 70 includes an inclined conveyance guide 72 on the downstream side of the contact glass 71 in the document conveyance direction.

  The inclined conveyance guide 72 includes an inclined surface 72a on the upper surface of the inclined conveyance guide 72 at a position where the original conveyed from the contact glass 71 side, that is, the upstream side contacts. The inclined surface 72a allows a document that has been out of the document conveying device 20 downward at a position of the document reading unit 33 to read an image drawn on the document by the image reading device 70, and again returns to the upper document conveying device 20. In order to guide to the inside, it has a slope that rises as it goes downstream.

  On the other hand, the document feed unit 30 of the document transport device 20 corresponding to the downstream side of the inclined transport guide 72 in the document transport direction is provided with a driven roller 55 that is a rotating body. The driven roller 55 is disposed on the downstream side of the inclined conveyance guide 72 in the document conveyance direction and upstream of the conveyance roller pair 42 provided in the document feeding unit 30 and above the document conveyance path.

  Further, as shown in FIG. 4, the driven roller 55 has a lower end where the upper guide member protrudes most toward the image reading device 70 between the document reading unit 33 and the driven roller 55. It is positioned below a straight line M extending along the document conveying direction that connects the downstream portion of the bottom surface of the reading guide member 41 facing the contact glass 71 and the nip N of the conveying roller pair 42.

  The driven rollers 55 are rotatable about an axis extending in the document width direction, and one follower roller 55 is arranged at the center of the document width direction or a plurality thereof are arranged in the document width direction. Unlike the roller pair, the driven roller 55 does not form a conveyance nip by contacting another rotating body or the like on its rotating surface, but contacts the document and rotates according to the conveyance of the document (see FIG. 5).

  The leading edge of the document that has passed through the portion of the inclined conveyance guide 72 normally reaches the nip N of the conveyance roller pair 42 without contacting the driven roller 55 due to the curvature of the document. Even when the leading edge of the document comes into contact with the driven roller 55, the driven roller 55 is provided at a position where the driven roller 55 can be prevented from being impacted by rotating. On the other hand, the conveyance roller pair 42 has a slightly higher rotational speed than the conveyance roller pair 40. As a result, as shown in FIG. 5, when the document is sandwiched between the pair of transport rollers 40 and 42, the document is pulled to the downstream side in the transport direction and contacts the driven roller 55.

  In this way, the document reading unit 33 that reads the image of the document by passing it over the contact glass 71 of the image reading device 70 in the middle of conveyance and the contact glass 71 are arranged immediately downstream of the document conveyance direction. In the document conveying device 20 including a pair of conveying rollers 42 provided on the downstream side of the inclined conveying guide 72 that guides the document that has passed the reading unit 33 into the upper document conveying device 20, the document of the inclined conveying guide 72 is provided. A driven roller 55 that is a rotating body that contacts the document and rotates in accordance with the conveyance of the document is provided on the downstream side in the conveyance direction and the upstream side of the conveyance roller pair 42 and above the document conveyance path. Without forcibly rubbing the document against the transport guide, the document transport path can be stabilized by making the vertical distance of the document transport path as narrow as possible. Frictional resistance during the original conveyed by the rotation of the roller 55 is also reduced. As a result, it is possible to prevent the occurrence of adverse effects caused by the friction between the document and the conveyance guide such as a protrusion. Therefore, at the location immediately downstream of the document reading unit 33, while preventing occurrence of problems such as noise, wear of the conveyance guide, wear of the document, oblique feeding, etc., the deflection and vibration of the document are suppressed and stable smoothness is achieved. Thus, it is possible to provide a document conveying device 20 capable of performing a proper document conveyance.

  The driven roller 55 has a lower end whose upper guide member protrudes most toward the image reading device 70 between the document reading unit 33 and the driven roller 55, and the nip N of the conveying roller pair 42. Is located below the straight line M extending in the document conveyance direction, so that the vertical interval of the document conveyance path can be further narrowed, and the document passing through the location of the driven roller 55 is conveyed to the conveyance roller pair 42. When sandwiched, the driven roller 55 is easily contacted. In this manner, the document transport path is stabilized, and the function of transporting the document while contacting the driven roller 55 is enhanced. Therefore, at the position immediately downstream of the document reading unit 33 in the document conveyance direction, the occurrence of problems such as noise, conveyance guide wear, document wear, and oblique feeding is prevented, and the document is prevented from being bent and oscillated. Improvement is achieved, and it becomes possible to perform more stable and smooth document conveyance.

  In the present invention, since the document conveying device 20 is mounted on the image forming apparatus 1, the document conveying device 20 is passed through the contact glass 71 of the image reading device 70 in the middle of the conveyance, so that the document reading unit 33 that reads the image of the document immediately passes. In the downstream area, the deflection and vibration of the document are suppressed while preventing the occurrence of problems such as noise caused by contact of the document with the conveyance guide such as protrusions, wear of the conveyance guide, wear of the document, and oblique feeding. Thus, it is possible to obtain a highly reliable image forming apparatus 1 capable of performing stable and smooth document conveyance.

  Although the embodiments of the present invention have been described above, the scope of the present invention is not limited to these embodiments, and various modifications can be made without departing from the spirit of the invention.

  For example, the image forming apparatus 1 equipped with the document conveying device 20 is an image forming apparatus for monochrome printing using only black toner in the above-described embodiment, but is not limited to such a model, and is not limited to intermediate transfer. An image forming apparatus for color printing of a tandem system or a rotary rack system that includes a belt and can superimpose a plurality of colors to form an image may be used.

  Further, in the above-described embodiment, the driven roller 55 having a relatively short length in the document width direction is disposed as a rotating body on the downstream side of the inclined conveyance guide 72 in the document conveyance direction and on the upstream side of the conveyance roller pair 42. However, a roller shape having a relatively long length in the document width direction may be arranged.

  According to the present invention, a document reading unit that reads an image of a document by passing it over the contact glass of the image reading device in the middle of conveyance, and the contact glass are disposed immediately downstream in the document conveyance direction and passed through the document reading unit. The present invention can be used in an original conveying apparatus including an original conveying roller pair provided on the downstream side of an inclined conveying guide that guides an original into the upper original conveying apparatus.

1 is a schematic vertical sectional front view of an image forming apparatus equipped with an original conveying apparatus according to an embodiment of the present invention. FIG. 2 is a schematic vertical sectional front view of the document conveying device of FIG. 1. FIG. 3 is a vertical sectional front view showing a document feeding portion of the document conveying device of FIG. 2. FIG. 4 is a partially enlarged vertical sectional front view showing the vicinity of a document reading unit of the document feeding unit of FIG. FIG. 5 is a partially enlarged vertical sectional front view showing the periphery of the document reading unit similar to FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Main body 20 Original conveying apparatus 21 Original placing tray 23 Original discharge tray 30 Original feeding part 33 Original reading part 41 Reading guide member 42 Conveying roller pair (original conveying roller pair)
55 Follower roller (rotating body)
70 Image Reading Device 71 Contact Glass 72 Inclined Conveyance Guide

Claims (3)

An original reading unit that reads an image of an original by passing it over the contact glass of the image reading apparatus in the middle of conveyance, and an original that is disposed immediately downstream of the contact glass in the original conveyance direction and has passed through the original reading unit, In a document conveying device comprising a pair of document conveying rollers provided on the downstream side of an inclined conveying guide that guides into the upper document conveying device,
A rotating body that contacts the document and rotates in accordance with the document conveyance is provided on the downstream side in the document conveyance direction of the inclined conveyance guide and on the upstream side of the document conveyance roller pair and above the document conveyance path. Document transport device.   The rotating body has a lower end that connects a portion of the upper guide member that protrudes most toward the image reading device between the document reading unit and the rotating body, and a nip of the document conveying roller pair. The document conveying apparatus according to claim 1, wherein the document conveying device is located below a straight line extending in the document conveying direction.   An image forming apparatus comprising the document conveying device according to claim 1.

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