JP2017202888A - Automatic document feeder and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an automatic document feeder and an image forming apparatus capable of locking a document tray at a prescribed angle and improving workability in taking out a small size document.SOLUTION: An ADF 5 includes support means 50A for supporting the attitude of a document tray 51 in a first state where a document sheet S placed on the document tray 51 can be conveyed and in a second state where the document tray 51 is lifted compared with the first state. The support means 50A includes a pair of rotating shafts 515a, 515b provided in the document tray 51, a pair of bearing parts 525a, 525b for receiving the pair of rotating shafts 515a, 515b so that the document tray 51 can rotate, and a plurality of stages of lock mechanisms 50. The plurality of stages of lock mechanisms 50 perform locking so as to prevent the document tray 51 from being lifted in the first state, and hold the document tray 51 in an inclination state in the second state where the document tray 51 is lifted to the maximum.SELECTED DRAWING: Figure 15

Description

  The present invention relates to an automatic document feeder having a rotatable document tray, and an image forming apparatus such as a multifunction printer provided with the automatic document feeder.

  In an image forming apparatus such as a general multifunction printer (MFP), an image forming unit, an image reading unit (scanner; SCN) placed on the image forming unit, and an image reading unit And an automatic document feeder (ADF) placed thereon.

  In this type of image forming apparatus, in order to reduce the size of the ADF for the purpose of downsizing, the space between the document tray and the discharge tray below it is designed to be small, so that the discharge discharge space is reduced. There are many things. In such an image forming apparatus, the document tray is configured to be rotatable so that the user can easily put a hand into the back of the document tray, thereby ensuring the ability to take out a small-size document on the discharge tray. ADF is already known (for example, Patent Document 1 and Patent Document 2).

  Specifically, Patent Document 1 discloses a configuration in which the document tray 5 is rotated about a vicinity of the upstream end of the document tray 5 in the document discharge direction (paragraphs 0051 and 0052, FIG. 2). Further, Patent Document 1 discloses that the lock unit 31 b of the filler 31 is associated with the document tray 5 in order to suppress fluttering of the automatic document feeder 1 when the automatic document feeder 1 is open with respect to the image reading device 2. The structure (paragraph 0068, FIG. 8, FIG. 9) which engages with the joint hole 5a and becomes a locked state is disclosed.

  Patent Document 2 discloses that an image reading apparatus in which the document feeder 1 can be opened and closed with respect to the scanner 2 and the sheet feed tray 3 can be opened and closed with respect to the document feeder 1. A member 248 is attached, and an engagement recess 247 is provided on the side of the document feeder 1 so that the sheet feeding tray 3 is not opened / closed by the opening / closing operation of the document feeder 1 by elastic engagement of both (paragraphs 0019 to 0021, 1, 5, and 6) are disclosed.

  Further, in Patent Document 3, in the automatic document feeder in which the reading unit casing 360 is rotatable about the drive shaft 230, the reading unit casing 360 is closed when the reading unit casing 360 is closed from the most opened state. A configuration in which the elastically deformable interference member 42 provided on the surface moves over the protrusion 41 provided on the frame main body 361 so as to reduce an impact when the reading unit housing 360 is closed (paragraphs 0037, 0038, FIGS. 3 and 4). Is disclosed.

  In recent years, this type of image reading apparatus has a function capable of reading a small-size original smaller than a normal original such as an A4 size or A5 size, such as a business card size original or a card original (hard sheet) such as a credit card. The development of the models we have is also progressing. In such a model, if the distance between the document tray and the paper discharge tray is designed to be small, it is more difficult to take out a small-size document discharged to the paper discharge tray.

  However, those described in Patent Documents 1 to 3 do not have a reading mechanism for small-size originals such as card originals, and the small-size originals are not discharged. The take-out property was not considered.

  In order to improve the take-out performance after ejecting small-size originals such as business card-size originals and card originals, including postcard-size originals, it is effective to make the document tray pivotable. In the documents 1 and 2, the document tray cannot be locked at an arbitrary angle while the automatic document feeder 1 is closed.

  Therefore, in Patent Documents 1 and 2, the document tray is always opened with one hand while the document tray is rotating when the above-mentioned small-size document discharged to the sheet discharge tray is taken out. It is necessary to take out the small-size original with the other hand from that state, and both hands have to be used for the operation for taking out the small-size original.

  Patent Documents 1 and 2 describe a technique described in Patent Document 3 in which an interference member is elastically deformed to overcome an impact when the reading unit housing is closed by overcoming a protrusion, thereby reducing the impact of the document tray. Even if it is used in the rotating mechanism, it is still necessary to hold the document tray with one hand during rotation, and eventually both hands have to be used to take out small-sized documents. There was a problem that it was difficult to take out.

  The present invention has been devised in view of the above points, and provides an automatic document feeder and an image forming apparatus capable of locking a document tray at a predetermined angle and improving workability when taking out a small-size document. The purpose is to do.

  In order to achieve the above object, an automatic document feeder according to the present invention conveys a document placed on a document tray to a predetermined reading position, and discharges it to a paper discharge tray disposed below the document tray. An automatic document feeder that performs the operation between a first state in which the document placed on the document tray can be transported and a second state in which the document tray is lifted from the first state. And supporting means for supporting the document tray so as to maintain the posture of the document tray in the first state and the second state.

  The present invention can provide an automatic document feeder and an image forming apparatus that can lock the document tray at a predetermined angle and can improve workability when taking out a small-size document.

1 is a perspective view illustrating a schematic configuration of an image forming apparatus according to an embodiment of the present invention. 1 is a front sectional view showing a schematic configuration of an image forming apparatus according to an embodiment of the present invention. 1 is a perspective view showing a configuration of hinge coupling between an apparatus main body and an automatic document feeder in an image forming apparatus according to an embodiment of the present invention. 3 is a top view of a document tray in the image forming apparatus according to the embodiment of the present invention. FIG. 1 is a schematic longitudinal sectional front view illustrating a configuration of a main part of an image reading unit in an image forming apparatus according to an embodiment of the present invention. It is explanatory drawing of the U-turn conveyance path | pass in the image reading apparatus which concerns on embodiment of this invention. It is explanatory drawing of the straight conveyance path | pass in the image reading apparatus which concerns on embodiment of this invention. It is explanatory drawing of the hard sheet supply in the image reading apparatus which concerns on embodiment of this invention. FIG. 6 is an explanatory diagram of the operation of the automatic document feeder in the image forming apparatus according to the embodiment of the present invention. FIG. 2 is a block diagram illustrating a control configuration of the image forming apparatus according to the embodiment of the present invention. It is a block diagram of a second reading unit in the image forming apparatus according to the embodiment of the present invention. 1 is a partially broken top view showing a configuration of an automatic document feeder having a multi-stage locking mechanism in an image forming apparatus according to an embodiment of the present invention. FIG. 13 is a schematic side view showing the configuration of the automatic document feeder as viewed from the direction of arrow DD in FIG. 12. It is a side view which expands and shows the structure of the principal part of the multistage latching mechanism shown in FIG. FIG. 5 is a schematic side view of a main part for explaining an operation mode of a multistage locking mechanism during a document tray lifting operation in the automatic document feeder of the image forming apparatus according to the embodiment of the present invention.

  Embodiments of the present invention will be described below with reference to the drawings.

  As shown in FIGS. 1 and 2, an image forming apparatus 1 according to the present embodiment is disposed on an apparatus main body 1M including a paper feeding unit 2, an image forming unit 3, and an image reading unit 4, and the apparatus main body 1M. A digital multi-function peripheral equipped with ADF5.

  The image reading unit 4 and the ADF 5 constitute an image reading device 6, and the ADF 5 constitutes an automatic document feeder. In the present embodiment, as will be described in detail later, the ADF 5 transports a document (hereinafter referred to as a document sheet S) placed on the document tray 51 one by one to a predetermined document reading position, and then the document tray 51. The paper is discharged to a paper discharge tray 53 arranged on the lower side.

  As shown in FIG. 2, the paper feed unit 2 includes a plurality of paper feed cassettes 21 </ b> A, 21 </ b> B, and 21 </ b> C that can store cut sheet-like transfer paper P (recording paper: white paper, for example) in a stacked state. Yes. In each of the paper feed cassettes 21A, 21B, and 21C, for example, transfer paper P having a sheet size selected in advance from a plurality of sheet sizes is accommodated in the vertical or horizontal paper feeding direction.

  The paper feeding unit 2 includes paper feeding devices 22A, 22B, and 22C that sequentially pick up and separately transfer the transfer paper P stored in the paper feeding cassettes 21A, 21B, and 21C from the respective uppermost layers. The paper feeding unit 2 is further provided with various rollers 23 and the like. By these, the transfer paper P fed from each of the paper feeding devices 22A, 22B, and 22C is transferred to a predetermined image forming position of the image forming unit 3. A sheet feeding path 24 is formed to convey the sheet.

  The image forming unit 3 is filled with toner of an exposure device (exposure unit) 31, photosensitive drums 32K, 32Y, 32M, and 32C, and black (K), yellow (Y), magenta (M), and cyan (C). Development devices 33K, 33Y, 33M, and 33C. The image forming unit 3 includes a primary transfer unit 34, a secondary transfer unit 35, and a fixing unit 36.

  For example, the exposure device 31 generates the laser light L for exposure of each color based on the image read by the image reading device 6. Further, the exposure device 31 exposes the photosensitive drums 32K, 32Y, 32M, and 32C of the respective colors with laser light, and static images of the respective colors corresponding to the read images on the surface layer portions of the photosensitive drums 32K, 32Y, 32M, and 32C. An electrostatic latent image is formed.

  The developing devices 33K, 33Y, 33M, and 33C supply thin layer toner to the corresponding photosensitive drums 32K, 32Y, 32M, and 32C so as to make the electrostatic latent image visible with the toner. Is supposed to do.

  The image forming unit 3 primarily transfers the toner image developed on the photosensitive drums 32K, 32Y, 32M, and 32C to the primary transfer unit 34, and the toner image is transferred by the secondary transfer unit 35 adjacent to the primary transfer unit 34. Secondary transfer is performed on the transfer paper P. Further, the image forming unit 3 heats and pressurizes the toner image secondarily transferred onto the transfer paper P and melts it, and fixes the color image on the transfer paper P for recording.

  The image forming unit 3 has a transport path 39A for transporting the transfer paper P carried from the paper feed unit 2 through the paper feed path 24 to the secondary transfer unit 35 side. In the transport path 39A, first, the transport timing and transport speed of the transfer paper P are adjusted by the registration roller pair 37. The transfer sheet P passes through the secondary transfer unit 35 and the fixing unit 36 in synchronization with the belt speed at the primary transfer unit 34 and the secondary transfer unit 35 and is then discharged onto the discharge tray 38. It is like that.

  The image forming unit 3 also has a manual paper feed path 39B that feeds the transfer paper P placed on the manual feed tray 25 to the transport path 39A on the upstream side of the registration roller pair 37.

  Below the secondary transfer unit 35 and the fixing unit 36, a switchback conveyance path 39C and a reverse conveyance path 39D each including a plurality of conveyance rollers and conveyance guides are disposed.

  When forming an image on both sides of the transfer paper P, the switchback transport path 39C moves backward after moving the transfer paper P on which one side of the image has been fixed from one end (moves in the opposite direction to the time of entry). ) To carry out switchback.

  The reverse conveyance path 39D reverses the front and back of the transfer paper P that is switched back by the switchback conveyance path 39C, and feeds the paper again to the registration roller pair 37.

  The transfer paper P that has been subjected to the image fixing process on one side by the switchback conveyance path 39C and the reverse conveyance path 39D is reversed in its forward and reverse directions, and again enters the secondary transfer nip. . The transfer paper P is discharged onto the paper discharge tray 38 after the secondary transfer processing and fixing processing of the image are performed on the other surface.

  The image forming unit 3 having the above-described configuration is based on the read image read by the image reading device 6 or print data transmitted from an external device such as a PC (personal computer), for example, the photosensitive drum 32K, 32Y, 32M, and 32C are exposed to form electrostatic latent images on the respective photosensitive drums 32K, 32Y, 32M, and 32C, and the developing devices 33K, 33Y, 33M, and 33C of the respective colors apply the latent images on the photosensitive drums. The toner is supplied to and developed. Further, the image forming unit 3 primarily transfers the toner images on the photosensitive drums 32K, 32Y, 32M, and 32C of the respective colors onto the transfer belt by the primary transfer unit 34, and superimposes them on the transfer paper P by the secondary transfer unit 35. After the secondary transfer, the toner image on the transfer paper P is fixed by heating and pressurizing by the fixing unit 36, and a color image can be formed.

  The image reading device 6 includes a DF scanner mode (conveyed document reading mode) for reading an image of a document sheet S (including a small size document such as a postcard size) during automatic conveyance, and a flat contact glass (a flat bed described later). It is configured to be switchable to a flat bed scanner mode (placed document reading mode) for reading an image of the document sheet S placed on the contact glass 41).

  In the flatbed scanner mode, the image reading unit 4 irradiates light on the image surface of the original sheet S (for example, original, cardboard, book, etc.) on the flatbed contact glass 41, and the reflected light from the image surface is imaged. The image on the original sheet S can be read by converting the signal.

  In the DF scanner mode, the ADF 5 separates the original sheets S one by one from the bundle of original sheets S stacked on the original tray 51 serving as a sheet placement table, and supplies the original sheets S to one end of the original tray 51. The original sheet S is carried in from the paper opening (first paper supply opening) 55a, and is conveyed along a U-turn conveyance path (first conveyance path) 56 constituted by a mechanism of the document conveyance section 52 described later. During the conveyance, the document sheet S sequentially faces the DF contact glass 42 on the upper surface side which is a predetermined document reading position of the image reading unit 4 sequentially from the upstream portion in the conveyance direction. That is, the image reading device 6 can perform the function of the DF scanner by sequentially reading the image of the document sheet S conveyed by the ADF 5 on the DF contact glass 42 of the image reading unit 4.

  As shown in FIG. 3, the ADF 5 is attached to the rear part (the back side part) of the upper surface side of the apparatus main body 1M via an opening / closing mechanism such as a hinge. The ADF 5 can take an open position where the flat body contact glass 41 is opened with respect to the apparatus main body 1M and a closed position where the original sheet S on the flat bed contact glass 41 can be pressed.

  The image reading unit 4 is located above the apparatus main body 1M of the image forming apparatus 1. The image reading unit 4 includes a DF contact glass 42 positioned on the conveyance path of the original sheet S, a flat bed contact glass 41 on which the original sheet S can be placed, and a protrusion capable of abutting and positioning one side of the original sheet S. This member 43a is provided. Further, the apparatus main body 1M is provided with an operation unit 150 on the upper front side.

  The operation unit 150 includes a start button 151, a touch panel 152, and the like. When the start button 151 is pressed, the operation unit 150 requests the image forming apparatus 1 to start printing or data transmission.

  The ADF 5 is connected to an upper portion of the apparatus main body 1M of the image forming apparatus 1 through a hinge mechanism 1h so as to be opened and closed, and a document presser 43b is mounted on the lower surface. The ADF 5 is rotated between an open position where the DF contact glass 42 and the flat bed contact glass 41 are exposed in the image reading unit 4 and a closed position where the DF contact glass 42 and the flat bed contact glass 41 are covered. It has become.

  As shown in FIG. 4, the document tray 51 is mounted with a pair of left and right movable side guide plates 54 for positioning the document sheet S set on the ADF 5 in the sheet width direction orthogonal to the sheet feeding direction. These side guide plates 54 can be relatively approached and separated so that the center of the document tray 51 and the document sheet S in the width direction coincide with each other. However, the side guide plate 54 may be one in which one edge of the document sheet S is brought into contact with one edge of the document tray 51 so that only the other edge can be moved.

  A document set sensor 82 for detecting whether or not the document sheet S is placed on the document tray 51 is provided near the bottom surface near the front end of the document tray 51.

  The ADF 5 is covered with a cover 55 that can be opened and closed at least above. The cover 55 is formed with a paper feed port 55 a above the vicinity of the end of the document tray 51 on the paper feed side so that the front end of the document sheet S in the transport direction enters the cover 55. Further, the cover 55 covers the upper portion of the document tray 51 in the transport direction so that the tip portion of the document tray 51 is housed inside the paper feed port 55a. In addition, the ADF 5 is formed with a main guide portion that forms the document conveying portion 52 from the paper supply port 55a to the discharge port 55b by ribs or the like formed on the cover 55 or the like.

  Further, the ADF 5 includes a supporting unit 50A for the document tray 51, which is a characteristic configuration of the present embodiment. In the present embodiment, the supporting unit 50A includes a first state in which the document sheet S placed on the document tray 51 can be conveyed, a second state in which the document tray 51 is lifted from the first state, The document tray 51 is supported so that the document tray 51 can rotate between the first and second states, and the document tray 51 is supported so as to maintain the posture of the document tray 51 in the first state and the second state.

  In the present embodiment, the second state is a state in which the document tray 51 is lifted up from the first state in which the document sheet S placed on the document tray 51 can be transported. The document tray 51 is rotating so that the user can insert a hand between them. Specifically, the second state is a state in which the document tray 51 is rotated (opened) to a predetermined angle within a range of, for example, 45 degrees from the first state where the document tray 51 is not opened, and is fixedly supported. .

  As described in detail later, the holding means includes a pair of rotating shafts 515a and 515b, a pair of bearing portions 525a and 525b that receive the pair of rotating shafts 515a and 515b so that the document tray 51 can rotate, and a plurality of stages. And a locking mechanism 50.

  The pair of rotation shafts 515 a and 515 b are provided on the pair of ribs 510 a and 510 b on both sides in the main scanning direction of the document sheet S of the document tray 51. The pair of rotating shafts 515a and 515b are provided inside the wall surface of the document transport path 52 of the pair of guide members 521a and 521b that support the document tray 51 and form the document transport path 52 that transports the document sheet S. The multi-stage locking mechanism 50 is provided in a distributed manner between the pair of ribs 510a and 510b and the portions corresponding to the ribs 510a and 510b of the pair of guide members 521a and 521b (FIGS. 2 and 4). (See FIGS. 6 and 7).

  The multistage locking mechanism 50 is a mechanism that fixes (locks) the document tray 51 to any one of a plurality of stages of lock positions with different inclination angles of the document tray 51. The multistage locking mechanism 50 will be described in detail later with reference to FIGS.

  Next, the configuration of the image reading unit 4 will be described with reference to FIG. The image reading unit 4 constitutes an image reading device 6 together with the ADF 5. 5 shows a main part of the image reading unit 4, FIG. 5 (A) is a schematic longitudinal front view in the flatbed scanner mode, and FIG. 5 (B) is an integrated optical at the time of mode switching. FIG. 5C is a schematic longitudinal sectional front view showing the scanning unit moving, and FIG. 5C is a schematic longitudinal sectional front view in the DF scanner mode.

  The flat bed contact glass 41 faces the image surface of the original sheet S when the image reading apparatus 6 functions as a flat bed scanner and the original sheet S to be read is placed. . Further, the DF contact glass 42 faces the image surface of the original sheet S passing through a predetermined reading position of the U-turn conveyance path 56 when the image reading device 6 functions as a DF scanner. Further, as shown in FIG. 5A, the DF contact glass 42 is inclined with respect to the flat bed contact glass 41 so as to make a preset inclination angle θ.

  Inside the image reading unit 4, a first reading unit 45 and a guide rod 46 extending in the left-right direction are provided. The first reading unit 45 includes an integrated optical scanning unit 47, a bracket 48 that holds the integrated optical scanning unit 47, and a plurality of compression coils that are assembled in a compressed state between the integrated optical scanning unit 47 and the bracket 48. A spring 49 is included.

  The integrated optical scanning unit 47 is configured, for example, as a contact image sensor in which a mold frame is held with an equal magnification imaging element roof mirror lens array, an optical path separation mirror, an equal magnification image sensor, an illumination light source, and the like. The integrated optical scanning unit 47 can scan an image with high resolution in the main scanning direction, and has a large depth of focus that can be used for reading an image of a book document or the like.

  The integrated optical scanning unit 47 is not limited to a specific method as long as the integrated optical scanning unit 47 is configured to be compatible with a DF scanner and a flat bed scanner. The main scanning direction is a direction parallel to both the upper surface of the flat bed contact glass 41 and the upper surface of the DF contact glass 42.

  The bracket 48 includes a lower slider portion 48a supported by the guide rod 46, a pair of holding arm portions 48b for holding the integrated optical scanning unit 47, and the lower slider portion 48a and the pair of holding arm portions 48b. And a bracket main body portion 48d attached thereto.

  Here, the lower slider portion 48a is formed of a cylindrical body fixed to the lower portion of the center in the longitudinal direction of the bracket main body portion 48d, and the pair of holding arm portions 48b are located on the upper side in the figure at both end sides of the bracket main body portion 48d. It is comprised by a pair of plate-shaped body which protrudes. The pair of holding arm portions 48b are arranged in the vertical direction so as to hold the both-end protruding portions 47a protruding vertically from both end faces of the integrated optical scanning unit 47 so that the posture can be changed around the longitudinal axis and the vertical displacement is possible. Has a long hole (oblong hole) 48c.

  The plurality of compression coil springs 49 press the lower surface portion of the integrated optical scanning unit 47 to the upper side (flat bed contact glass 41 side, DF contact glass 42 side) at a plurality of locations in the main scanning direction.

  In addition, a rectangular annular upper slider portion 47b that slides smoothly in the sub-scanning direction while being in contact with the lower surface of at least one of the flat bed contact glass 41 and the DF contact glass 42 is mounted on the upper part of the integrated optical scanning unit 47. Has been.

  The upper slider portion 47b may be a protrusion that extends in the longitudinal direction or the short side direction of the integrated optical scanning unit 47 and is spaced apart from each other in a direction orthogonal to the extending direction. Further, the upper slider portion 47b may be composed of a plurality of hemispherical protrusions or the like. In any case, the upper slider portion 47b is made of a material that has a low coefficient of friction, good slidability / slidability with respect to the lower surface of the flat bed contact glass 41 and the DF contact glass 42, or an alternative guide surface, and can be lubricated. It should be formed.

  As shown in FIGS. 5A, 5B, and 5C, the integrated optical scanning unit 47 is guided so as to be movable in the sub-scanning direction by a guide rod 46 disposed below the bracket 48. Yes. Depending on the position in the sub-scanning direction, the integrated optical scanning unit 47 slides on either one or both of the flat bed contact glass 41 and the DF contact glass 42 held by the holding member 43 at the upper part. Abuts as possible. Accordingly, the first reading unit 45 is movable along the guide rod 46, but the inclination of the guide rod 46 around the axis is restricted.

  The first reading unit 45 can read the image of the document sheet S by performing line scanning on the image surface of the document sheet S on the flat bed contact glass 41 in the main scanning direction and moving in the sub-scanning direction. Further, the first reading unit 45 can read the image of the document sheet S by performing line scanning in the main scanning direction on the image of the transported document passing over the DF contact glass 42.

  In addition, a timing belt in which the bracket 48 of the first reading unit 45 is fixed at one place in the circumferential direction in an endless loop shape is provided inside the image reading unit 4. The image reading unit 4 includes a plurality of timing pulleys on which the timing belt is stretched without slack, a motor that rotationally drives any one of the timing pulleys, and the like.

  When performing the reading operation in the flatbed scanner mode, the first reading unit 45 moves from the home position to one side in the sub-scanning direction, for example, from the home position near the stop position indicated by the dotted line in FIG. Move to. Then, line scanning by the integrated optical scanning unit 47 is executed for each minute movement distance, and an image on the surface (lower surface) of the placed document sheet S on the flat bed contact glass 41 is read. When the reading operation is completed, the first reading unit 45 returns to the home position again.

  When performing the reading operation in the DF scanner mode, the first reading unit 45 moves from the home position to below the DF contact glass 42 as shown by a solid line in FIG. In other words, the first reading unit 45 moves to the other side in the sub-scanning direction by a preset distance from the home position, stops below the DF contact glass 42, and passes through the DF contact glass 42. Read the surface image.

  As described above, the first reading unit 45 is movable in the sub-scanning direction so as to be positioned on the lower side of the flat bed contact glass 41 and the lower side of the DF contact glass 42. The integrated optical scanning unit 47 has a horizontal first reading posture in which an image can be read through the flat bed contact glass 41 as shown in FIG. 5A according to the position in the sub-scanning direction, and FIG. The posture changes to an inclined second reading posture in which an image can be read through the DF contact glass 42 as shown in FIG.

  Next, the configuration of the ADF 5 will be described with reference to FIGS. FIG. 6 is a diagram illustrating a mechanism in which the ADF 5 transports the document sheet S from the document tray 51 through the U-turn transport path 56.

  As shown in FIG. 6, the ADF 5 includes a document tray 51 as a document placing table on which a standard document sheet S can be placed, a document transport unit 52 that transports the document sheet S so that an image can be read, and a post-image reading unit. A paper discharge tray 53 on which the original sheets S are stacked is provided. The document tray 51 and the paper discharge tray 53 are arranged so as to overlap each other with at least a part of them separated for the purpose of downsizing.

  The document transport unit 52 includes a separation unit 52 a that separates the topmost document sheet S one by one from the bundle of document sheets S placed on the document tray 51 and loads the separated document sheet S into the document transport unit 52. The document conveying section 52 has a plurality of conveying rollers 52b, 52c, and 52d for inverting the separated and loaded document sheet S. After the document sheet S is folded, the document sheet S is folded. Is passed along the DF contact glass 42 through a predetermined reading operation position Pd1 on the upper surface thereof. The document conveying section 52 has a pair of discharge rollers 52e and 52f on the further downstream side. The U-turn conveyance path 56 is a path along which the document sheet S is conveyed by the mechanism of the document conveyance unit 52. The number and location of the rollers for conveying and discharging can be arbitrarily set according to the path setting conditions of the document conveying section 52, the minimum size of the document sheet S in the document conveying direction, and the like. .

  When the integrated optical scanning unit 47 constituting the first reading unit 45 is located at a position indicated by 47 (Pb) in FIG. 6, that is, a solid line position in FIG. The integrated optical scanning unit 47 can scan a line repeatedly at the reading operation position Pd1 to read a document image. Then, the document sheet S after the image reading is discharged to the discharge tray 53 by the discharge roller pair 52e, 52f.

  In addition to the separation unit 52a, the conveyance rollers 52b, 52c, and 52d and the discharge roller pair 52e and 52f, the document conveyance unit 52 is a controller that performs conveyance control based on the plurality of sensors arranged and detection information thereof. have. The plurality of sensors include, for example, a known proper feeding position sensor 92, abutment sensor 93, document width sensor 94, reading entrance sensor 95, registration sensor 96, paper discharge sensor 97, table lift sensor 98, and the like (see FIG. 10). These sensors are arranged in order from the upstream side in the conveyance direction of the document sheet S to the downstream side. Of course, the normal document sheet S is a PPC or other easily bent sheet that can form an image recording surface.

  Further, the document conveying section 52 extends while being inclined along the DF contact glass 42 in a predetermined conveying section on the downstream side from the nip position of the conveying rollers 52c and 52d on the upstream side of the DF contact glass 42 to the discharge port 55b. A straight conveyance path (second conveyance path) 56a is formed.

  FIG. 7 is a diagram for explaining a mechanism in which the ADF 5 transports the original sheet S from a paper feed port (second paper feed port) 72 of a card supply tray (manual tray) 73 shown in FIG. It is.

  As shown in FIG. 7, in the straight conveyance path 56 a, a hard sheet having a higher bending rigidity than a normal document sheet S, in particular, a small-sized hard sheet H is fed from a paper feed port 72 of a card supply tray (manual feed tray) 73. It is a transport path that is transported along a plane that is carried in and inclined so as to be parallel to the upper surface of the DF contact glass 42. Further, when being conveyed in the straight conveyance path 56a, the hard sheet H passes through a predetermined reading operation position Pd1 on the DF contact glass 42.

  The small-sized hard sheet H here is a standard standard size card formed of resin or the like (may be cardboard), such as a license, an ID card (identification card), a transportation card, etc. As shown in FIG. 6, it is a type of document that cannot be reversed so as to be folded by the conveying rollers 52b, 52c, and 52d.

  That is, the hard sheet H is not suitable for the U-turn conveyance path 56 for inverting the original sheet S as shown in FIG. 6, but is suitable for the straight conveyance path 56a shown in FIG. The small size here is, for example, one of ID-1, ID-2 or ID-3 of ISO / IEC 7810, which is an international standard that defines the shape of an identification card, or a card size comparable to that. is there. However, the width in the short direction of the card size is set to be smaller than the width in the short direction of the cut sheet of the minimum size among the standard cut sheet sizes set on the document tray 51.

  The plurality of transport rollers 52c and 52d and the discharge roller pair 52e and 52f that form the straight transport path 56a together with a plurality of sensors arranged on the straight transport path 56a and a controller that performs transport control based on detection information thereof. The second document conveying portion 61 is configured. Therefore, the second document conveying section 61 carries a small-size hard sheet H from one end side of the straight conveyance path 56a, that is, the paper feed port 72, and discharges the hard sheet H conveyed along the straight conveyance path 56a. The paper is discharged from the other end of the straight conveyance path 56a on the paper area side, that is, from the discharge port 55b.

  As shown in FIG. 8, the card supply unit 71 includes a paper feed port 72 provided on the side surface of the ADF 5 and a card supply tray 73. The card supply unit 71 further includes a card pickup roller 74, which will be described later, and a card transport path 75 (see FIG. 9).

  Near the bottom surface of the card supply tray 73, a document set sensor 82 for detecting whether or not a document, that is, a hard sheet H is placed on the card supply tray 73 is provided.

  The card supply tray 73 is normally closed and constitutes a part of the side surface of the cover 55, and is rotatable so as to open the paper feed port 72 as shown in FIGS. 8 and 9. When the card supply tray 73 is in a closed state, the card supply tray 73 becomes a part of a conveyance guide for the original sheet S that is a normal original.

  The card pickup roller 74 takes out the hard sheet H set on the card supply tray 73 and supplies the card to the card transport path 75 via the paper feed port 72. The card transport path 75 is a path from the paper feed port 72 to the DF contact glass 42 inclined downward, and joins the U-turn transport path 56 on the upstream side of the DF contact glass 42.

  At this time, the card conveyance path 75 is located on the same plane along the inclination angle of the DF contact glass 42 in the range from the paper feed port 72 to the DF contact glass 42 with the downward inclination of the DF contact glass 42. Yes. Accordingly, the card transport path 75 and the straight transport path 56a are located on the same plane along the inclination angle of the DF contact glass 42 in the entire range from the paper feed port 72 to the discharge port 55b. That is, the hard sheet H carried in from the card supply tray 73 is conveyed along the card conveyance path 75 and the straight conveyance path 56a.

  As described in detail in FIG. 9, the document conveying unit 52 is located on the upper end of the document tray 51 at the upstream end on the side of the sheet feeding port 55 a with respect to the document conveying direction of the document sheet S. It has the set filler 57 which rotates by mounting. The document conveying section 52 is composed of a pickup roller 58 disposed near the inside of the sheet feeding port 55a, a sheet feeding roller 59 disposed so as to face the U-turn conveying path 56, and a separation plate 60. And a unit 52a.

  The pickup roller 58 picks up several (ideally one) original sheets S from the uppermost side among the original sheets S stacked on the original tray 51 at the contact position.

  The paper feed roller 59 is rotatable in the document feeding direction. When the plurality of document sheets S are about to be fed, the separation plate 60 becomes the resistance of the document sheet S other than the topmost sheet with respect to the rotational movement direction of the sheet feeding roller 59, and thereby the document sheet S. Suppresses double feeding. The paper feed roller 59 may be of a belt type, or the separation plate 60 may be of a roller type that rotates in the opposite direction to the paper feed roller (paper feed belt).

  The conveyance rollers 52b, 52c, and 52d arranged adjacent to the downstream side of the paper feed roller 59 abut on the leading edge of the fed document sheet S in accordance with the drive timing of the pickup roller 58 to correct skew conveyance. The document sheet S after correction is pulled out and conveyed.

  The document conveying section 52 is disposed so as to face the upper side of the DF contact glass 42, and is disposed immediately before the discharge port 55b and a first reading roller 66 that reads an image of the document sheet S, and the document sheet S. And a discharge roller pair 52e, 52f that discharges the toner toward the discharge tray 53 from the discharge port 55b.

  The first reading roller 66 is biased toward the DF contact glass 42 using a biasing member such as a coil spring, and causes the document sheet S to adhere to the DF contact glass 42 while conveying the document sheet S. It is like that.

  The document conveying section 52 is located on the downstream side of the first reading roller 66 on the path for conveying the document sheet S relatively linearly between the conveying rollers 52b, 52c, 52d and the discharge roller pair 52e, 52f. A reading unit 68 is arranged.

  The second reading unit 68 is disposed so as to face the back surface scanning unit 69 as a reading unit that reads back images of the original sheet S and the hard sheet H, and the back surface scanning unit 69 with the straight conveyance path 56a interposed therebetween. And a roller 70.

  The back surface scanning unit 69 is a contact type so as to read the back surface images of the original sheet S and the hard sheet H after the front images of the original sheet S and the hard sheet H are read by the integrated optical scanning unit 47 of the image reading unit 4. An image sensor or the like is used.

  The second reading roller 70 suppresses the floating of the original sheet S and the hard sheet H in the back surface scanning unit 69, and also serves as a reference white portion for acquiring shading data in the back surface scanning unit 69. Note that the original sheet S and the hard sheet H pass through the back surface scanning unit 69 when reading of the back image of the original sheet S and the hard sheet H is not performed.

  The second reading roller 70 maintains an appropriate distance according to the depth of focus that does not impair the image quality with respect to the distance (conveyance gap) between the back surface scanning unit 69 and the original sheet S or the hard sheet H by the gap adjusting mechanism. It has become.

  Next, the document reading operation of the ADF 5 will be described with reference to FIGS. In the above configuration, when reading an image on the original sheet S, as shown in FIG. 6, the original sheet S is set on the original tray 51 and the start button 151 is pressed to start from the uppermost original sheet S. Then, the sheet is fed out to the U-turn conveyance path 56 via the sheet feeding port 55a.

  Then, as shown in FIG. 9A, the document sheet S set on the document tray 51 is fed out to the U-turn conveyance path 56 via the paper feed port 55a, and is indicated by a circle in the drawing. The U-turn is conveyed so as to be folded back on the U-turn conveyance path 56g. Thereafter, when the original sheet S passes through the upper surface of the DF contact glass 42, the original sheet S is brought into close contact with the DF contact glass 42 by the pressure of the first reading roller 66, and is placed on one side by the integrated optical scanning unit 47 as an image sensor ( For example, a surface image is read.

  Further, when reading an image on the other side (for example, the back side) of the original sheet S, the second reading roller 70 pressurizes the original sheet S when the original sheet S passes through the back side scanning unit 69. Meanwhile, the image on the other side (for example, the back side) is read by the back side scanning unit 69. Then, the original sheet S after reading the image on the other side is discharged from the discharge port 55b toward the discharge tray 53 by the discharge roller pair 52e, 52f.

  On the other hand, originals smaller than the minimum size original sheet S (for example, postcard size) set in the original tray 51, particularly hard sheets such as thick resin cards such as cash cards of banks and various credit cards. When reading the H image, first, as shown in FIG. 8, the paper supply port 72 is opened by the card supply tray 73.

  In this state, the hard sheet H is set on the card supply tray 73 and the start button 151 is pressed, so that the hard sheet H is sequentially fed out to the card transport path 75 via the paper feed port 72. The card conveyance path 75 is generally on the same plane, and the adjacent interval between the card pickup roller 74, the first reading roller 66, and the discharge roller pair 52e, 52f composed of two rollers is the same as that of the hard sheet H. It is arranged below the vertical size (or horizontal size).

  As shown in FIG. 9B, when the hard sheet H fed to the card transport path 75 via the paper feed port 72 passes through the upper surface of the DF contact glass 42, the first reading roller An image of one surface (for example, the front surface) is read by the integrated optical scanning unit 47 while being in close contact with the DF contact glass 42 under the pressure of 66.

  Furthermore, when reading an image on the other surface (for example, the back surface) of the hard sheet H, the hard sheet H is in close contact with the back surface scanning unit 69 by the pressure of the second reading roller 70 when passing through the back surface scanning unit 69. In the meantime, the image on the other side is read by the back surface scanning unit 69. Then, the hard sheet H after reading the image on the other side (for example, the back side) is discharged toward the discharge tray 53 from the discharge port 55b by the discharge roller pairs 52e and 52f.

  As described above, the image forming apparatus 1 according to the embodiment of the present invention includes a document tray 51 on which a document sheet S to be scanned is loaded, and a sheet feeding port for taking out the document sheet S stacked on the document tray 51. 55a, a document transport unit 52 that transports the document sheet S taken out from the paper feed port 55a, an integrated optical scanning unit 47 that is disposed in the document transport unit 52 and reads an image on one side of the document sheet S being transported, A back-side scanning unit 69 that reads an image on the other side of the original document sheet S that is arranged in the original conveyance unit 52 and supplies the hard sheet H to the original conveyance unit 52 that is provided separately from the paper feed port 55a. By providing a paper port 72 and a straight transport path 56a in which a transport path from the paper feed port 72 through the back surface scanning unit 69 to the discharge port 55b is located on the same plane, A While contributing to miniaturization and shortening the reading time of F5, it is possible to allow reading of the thick resin cards, a small size, corresponding to the diversification of reading such a document sheet S, and the hard sheet H.

  Next, the control configuration of the operation of the image forming apparatus 1 will be described with reference to FIG. As shown in FIG. 10, the image forming apparatus 1 includes a controller unit 100 for automatic document conveyance control, a main body control unit 111 for controlling the main body of the apparatus, and an operation unit 150 attached to the main body control unit 111. .

  The controller unit 100 captures detection signals from the document set sensor 82, the appropriate paper feed position sensor 92, the abutment sensor 93, the document width sensor 94, the reading entrance sensor 95, the registration sensor 96, the paper discharge sensor 97, and the table lift sensor 98. It is like that.

  The controller unit 100 includes a pickup motor 101 that drives the pickup roller 58, a paper feed motor 102 that drives the paper feed roller 59 and the transport rollers 52b, 52c, and 52d, and a reading motor 103 that drives a timing pulley that moves the bracket 48. The sheet discharge motor 104 that drives the discharge roller pairs 52e and 52f and the bottom plate raising motor 105 that moves up and down the movable document table 51a (see FIG. 4) of the document tray 51 are operated.

  The controller unit 100 detects the timing at which the leading edge of the document sheet S or the hard sheet H reaches the reading position of the integrated optical scanning unit 47 with respect to the integrated optical scanning unit 47 (the image data thereafter is treated as effective data). A timing signal for notifying the second scanning unit 68, and a timing at which the leading edge of the original sheet S or the hard sheet H reaches the reading position of the back surface scanning unit 69 with respect to the second reading unit 68 (the image data after that) A timing signal or the like for notifying that is treated as valid data) is output.

  The controller unit 100 and the main body control unit 111 are connected via an interface circuit 107. When the start button 151 of the operation unit 150 is pressed, the main body control unit 111 transmits a document feed signal and a reading start signal to the controller unit 100 via the interface circuit 107.

  Next, a signal path between the image reading apparatus 6 and the image forming apparatus 1 will be described with reference to FIG.

  As shown in FIG. 11, the second reading unit 68 includes a light source unit 200 including an LED array, a fluorescent lamp, a cold cathode tube, or the like. The light source unit 200 irradiates light on the document sheet S based on a lighting signal from the controller unit 100. The second reading unit 68 is configured to obtain a timing signal for notifying the timing when the leading edge of the document sheet S reaches the reading position of the back surface scanning unit 69 from the controller unit 100 and the power source of the light source unit 200.

  The second reading unit 68 includes a plurality of sensor chips 201 arranged in the main scanning direction, a plurality of OP amplifier circuits 202 individually connected to the respective sensor chips 201, and individually connected to the respective OP amplifier circuits 202. And a plurality of A / D converters 203. Further, the second reading unit 68 includes an image processing unit 204, a frame memory 205, an output control circuit 206, an interface circuit 207 (denoted as an I / F circuit in the drawing), and the like.

  The sensor chip 201 includes a photoelectric conversion element called a 1 × contact image sensor and a condenser lens. The reflected light reflected from the surface of the original sheet S is condensed on the photoelectric conversion elements by the condensing lenses of the plurality of sensor chips 201 and read as image information.

  Image information read by each sensor chip 201 is amplified by an OP amplifier circuit 202 and then converted into digital image information by an A / D converter 203.

  The digital image information is input to the image processing unit 204 and subjected to shading correction, and then temporarily stored in the frame memory 205. Further, the digital image information is converted into a data format that can be received by the main body control unit 111 by the output control circuit 206 and then output to the main body control unit 111 via the interface circuit 207.

  Next, the multi-stage locking mechanism 50 of the document tray 51 provided in the automatic document feeder (ADF 5) according to the present embodiment will be described with reference to FIGS. For convenience of description of the multi-stage locking mechanism 50, the configuration shown in FIGS. 12 to 15 is omitted from the configuration of the movable document table 51a (see FIG. 4) provided near the leading end side of the document tray 51. Yes.

  The multi-stage locking mechanism 50 is based on a tray rotation mechanism that supports the document tray 51 to be rotatable with respect to the ADF 5. First, the tray rotation mechanism will be described.

  As shown in FIG. 12, the ADF 5 includes the above-described document transport unit 52 and a transport path portion on the upstream side of the document transport unit 52 in the document transport direction, and the document sheet S between the document tray 51 and the discharge tray 53. Guide members 521a and 521b that form a document conveyance path 520 for conveying the document. Further, in the ADF 5, the document tray 51 has a pair of ribs 510a and 510b positioned on both sides in the main scanning direction of the base end portion 520c of the guide members 521a and 521b at the distal end on the downstream side in the document conveyance direction.

  The pair of ribs 510a and 510b of the document tray 51 are provided with a pair of rotating shafts 515a and 515b protruding from the ribs 510a and 510b to the wall surface side of the document transport path 520 of the guide members 521a and 521b. The pair of ribs 510a and 510b and the rotation shafts 515a and 515b are located in the document conveyance path 520. In addition, a pair of guide members 521a and 521b that form the document transport path 520 of the ADF 5 has a pair of bearing portions 525a and a pair of bearing portions 525a that rotatably receive the rotary shafts 515a and 515b formed on the pair of ribs 510a and 510b, respectively. 525b is formed.

  As described above, in the ADF 5, the document tray 51 has the pair of ribs 510a and 510b on both sides of the base end portion 520c of the guide members 521a and 521b in the main scanning direction, and the pair of guide members 521a and 521a from the ribs 510a and 510b. It has a pair of rotating shafts 515a and 515b projecting to the wall surface side of the document conveying path 520 of 521b.

  In the ADF 5, the pair of ribs 510a and 510b and the rotation shafts 515a and 515b are positioned in the document conveyance path 520, and the rotation shafts 515a and 515b are provided on both side portions in the main scanning direction of the document conveyance path 520 of the guide members 521a and 521b. The bearings 525a and 525b provided are rotatably supported. As a result, the ADF 5 has a tray rotation mechanism that allows the document tray 51 to rotate about the rotation shafts 515a and 515b.

  13 shows the configuration of the ADF 5 as viewed from the direction of the arrow DD in FIG. 12, and FIG. 13A is a schematic side view showing a first state where the document tray 51 is not opened. B) is a schematic side view showing a second state in which the document tray 51 is lifted to the maximum.

  The ADF 5 having the tray rotation mechanism described with reference to FIG. 12 moves the document tray 51 between, for example, a first state shown in FIG. 13A and a second state shown in FIG. That is, it can be rotated between a state where it is not lifted and a tilted state where it is lifted to the maximum.

  Here, when the document tray 51 is not lifted, the distance between the document tray 51 and the paper discharge tray 53, that is, taking out the document discharged to the paper discharge tray 53, compared to the state where the document tray 51 is not lifted. Space is getting bigger.

  In the present embodiment, the tray rotation mechanism of the ADF 5 is either in a state where the document tray 51 is not lifted (see FIG. 13A) or in a tilted state where the document tray 51 is lifted to the maximum (see FIG. 13B). The multi-stage locking mechanism 50 that locks in this state is provided.

  Next, the multistage locking mechanism 50 will be described in more detail with reference to FIG. 14 shows an enlarged structure of a main part of the multi-stage locking mechanism 50 shown in FIG. 12, and FIG. 14 (A) is a side view showing the configuration viewed from the direction of the arrow EE in FIG. FIG. 13B is a side view showing the configuration viewed from the direction of the arrow FF in FIG.

  As shown in FIG. 12, the multi-stage locking mechanism 50 includes the ribs 510a and 510b constituting the tray rotating mechanism described above, and the portions corresponding to the ribs 510a and 510b of the guide members 521a and 521b. They are distributed between each other.

  Specifically, in the multi-stage locking mechanism 50, the configuration between the rib 510a and the portion corresponding to the rib 510a of the guide member 521a, as viewed from the arrow EE line in FIG. 12, that is, FIG. A) and a structure corresponding to the rib 510b of the guide member 521b as viewed from the arrow FF line in FIG. That is, it has the configuration shown in FIG. 14B (hereinafter, the configuration on the rib 510b side).

  As shown in FIGS. 14A and 14B, the multi-stage locking mechanism 50 includes a plurality of locking recesses 512a, 512b and 513a, 513b provided in the ribs 510a, 510b, and a rib 510a. , 510b and a pair of protrusions 526a, 526b disposed on the guide members 521a, 521b side, and the protrusions 526a, 526b are urged in a direction to engage with the locking recesses 512a, 512b and 513a, 513b. Retaining cylindrical portions 528a and 528b for accommodating the elastic members 527a and 527b, the protrusions 526a and 526b, and the elastic members 527a and 527b, respectively.

  When the document tray 51 is not lifted (see FIGS. 13A and 14A), the multi-stage locking mechanism 50 is one of the plurality of locking recesses 512a, 512b and 513a, 513b. One locking recess, for example, 512a and 512b engages with the corresponding projections 526a and 526b, so that the document tray 51 is locked from being lifted.

  Further, when the document tray 51 is tilted to the maximum (see FIG. 13B), the multi-stage locking mechanism 50 is the other of the plurality of locking recesses 512a, 512b and 513a, 513b. The locking recesses 513a and 513b are engaged with the corresponding projections 526a and 526b, so that the document tray 51 is locked so as to maintain the inclined state.

  In the multi-stage locking mechanism 50, each rib 510a, 510b has an outer peripheral portion 511 formed in a fan shape on the lower side with respect to the corresponding rotation shafts 515a, 515b, and a plurality of bay-shaped concave portions are formed in the outer peripheral portion 511. 514a and 514b are formed. The bay-shaped recesses 514a and 514b constitute the locking recesses 512a and 512b and 513a and 513b described above, respectively.

  In the multi-stage locking mechanism 50, the protrusions 526a and 526b provided on the guide member 521a on the rib 510a side and the guide member 521b on the rib 510b side are respectively positioned below the corresponding ribs 510a and 510b and correspondingly rotated. The shafts 515a and 515b are provided so as to advance and retreat in the central direction.

  The locking recesses 512a, 512b and 513a, 513b provided on the corresponding ribs 510a, 510b of the projections 526a, 526b, that is, the portions engaging with the bay-shaped recesses 514a, 514b are formed in a hemispherical surface. Yes. On the other hand, the portions engaging with the corresponding protrusions 526a and 526b of the bay-shaped recesses 514a and 514b constituting the locking recesses 512a and 512b and 513a and 513b have a wide opening on the protrusion side and are deeply engaged. It is formed in the shape of a taper groove that becomes gradually narrower in the direction in which it moves.

  Next, the operation of the ADF 5 provided with the multistage locking mechanism 50 will be described with reference to FIG. FIG. 15 shows the configuration on the rib 510a side as viewed from the arrow EE line in FIG. 12, but the configuration on the rib 510b side is also shown with parenthesized symbols for convenience of explanation. Yes.

  15A is a main part schematic side view showing a lock state of the multistage locking mechanism 50 in a state where the document tray 51 is not lifted. At this time, in the multistage locking mechanism 50, the protrusions 526a and 526b arranged on the guide members 521a and 521b side engage with the locking recesses 512a and 512b provided on the ribs 510a and 510b, respectively. Thus, the protrusions 526a and 526b are urged by the elastic members 527a and 527b so as to advance toward the center of the rotation shafts 515a and 515b, respectively, and the document tray 51 is locked so as not to be lifted.

  15B, FIG. 15B shows a state when the document tray 51 shown in FIG. 15A is not lifted and when the end on the downstream side in the document transport direction starts to be lifted upward (at the initial stage of lifting). FIG. 5 is a schematic side view of a main part showing a locking mode of a multistage locking mechanism 50. At this time, in the multistage locking mechanism 50, after the document tray 51 starts to be lifted, the ribs 510a and 510b continue in the direction indicated by the arrow g around the rotation shafts 515a and 515b formed on the guide members 521a and 521b. Is rotated.

  During the rotation of the ribs 510a and 510b, the projections 526a and 526b on the guide members 521a and 521b side slide with respect to the rotating recesses 512a and 512b, and the center direction of the rotation shafts 515a and 515b. Retreating continues in the reverse direction (the direction indicated by the arrow h in FIG. 15B).

  During this time, when the operation of further lifting the document tray 51 is continued, the protrusions 526a and 526b come out of the locking recesses 512a and 512b as shown in FIG. 15 (B) and come into the outer peripheral portions 511 of the ribs 510a and 510b. It comes into contact. When the operation of further lifting the document tray 51 is continued, the protrusions 526a and 526b are regions facing the respective locking recesses 513a and 513b provided in the ribs 510a and 510b through the state of FIG. To reach.

  In FIG. 15, FIG. 15C is a schematic side view of the main part showing the locking state of the multi-stage locking mechanism 50 when the document tray 51 is in the inclined state where it is lifted to the maximum. At this time, in the multistage locking mechanism 50, the protrusions 526a and 526b arranged on the guide members 521a and 521b side engage with the locking recesses 513a and 513b provided on the ribs 510a and 510b, respectively. Accordingly, the protrusions 526a and 526b are urged by the elastic members 527a and 527b so as to advance in the center direction of the rotation shafts 515a and 515b indicated by the arrow i in FIG.

  Thereby, in the ADF 5, the document tray 51 is locked in the tilted state where the document tray 51 is lifted to the maximum. In this inclined state, the distance between the lower surface side of the document tray 51 and the upper surface of the paper discharge tray 53 is increased, and the hard sheet H or the like that has been discharged is compared with the state shown in FIG. The space for taking out small-size originals increases. In addition, in this inclined state, the document tray 51 is held in the inclined state, so that it is not necessary to hold the document tray 51 when accessing a small-size document on the paper discharge tray 53.

  Therefore, in the ADF 5 according to the present embodiment, for example, as shown in FIG. 14A, after the hard sheet H read while transporting the straight transport path 56a described above is discharged onto the paper discharge tray 53, As shown in FIG. 14B, by lifting and locking the document tray 51 to the maximum, the hard sheet H can be easily taken out with one hand, and workability is improved. With regard to the above workability, the same effect can be expected for taking out a postcard-size or business card-size original document that has been read by being conveyed through the U-turn conveyance path 56.

  The image forming apparatus 1 according to the present embodiment is applied to, for example, a low-end machine having large restrictions on size, price, and the like. In the low-end machine, the height of the apparatus is small and the size is reduced, and since the distance between the document tray 51 and the paper discharge tray 53 is narrow, it is difficult for the user's hand to enter deeply. It is set so that hands can be inserted. Since the ADF 5 according to the present embodiment is used in a low-end machine in which the distance between the document tray 51 and the paper discharge tray 53 is narrow, the document tray 51 can be lifted to the maximum and locked in an inclined state. This is particularly useful for improving work when taking out a small-size document such as a hard sheet H discharged to the back side of the sheet.

  The ADF 5 according to the present embodiment is locked even when the document tray 51 is not lifted. For this reason, the ADF 5 also has the effect of suppressing flapping when the image reading unit 4 is rotated to the open position where the DF contact glass 42 and the flat bed contact glass 41 are exposed in a state where the document tray 51 is not lifted. .

  As described above, the automatic document feeder (ADF) 5 according to the present embodiment lowers the lower side of the document tray 51 after conveying the document sheets S placed on the document tray 51 one by one to a predetermined document reading position. In the first state in which the document sheet S placed on the document tray 51 can be conveyed, and the document tray 51 is more than in the first state. The support means 50A is provided so as to be able to rotate between the raised second state and the document tray so as to hold the posture of the document tray in the first state and the second state.

  According to this configuration, the document tray 51 is supported in the second state in which the user can insert a hand between the document discharge tray 53 and the document tray 51 remains fixed in that state. Can be taken out and the workability of taking out a small-size document can be improved. Further, by supporting the document tray 51 in the first state, it is possible to suppress fluttering of the document tray when the ADF 5 is opened with respect to the apparatus main body 1M of the image reading apparatus 1.

  In the present embodiment, the supporting means 50A is provided on a pair of ribs 510a and 510b on both sides of the document sheet S of the document tray 51 in the main scanning direction, and protrudes from the outside of each rib 510a and 510b in the main scanning direction. A pair of rotating shafts 515a and 515b and a pair of rotating shafts inside the wall surface of the document conveying path 52 of the pair of guide members 521a and 521b that support the document tray 51 and form the document conveying path 52 that conveys the document sheet S. A pair of bearings 525a and 525b, a pair of ribs 510a and 510b, and a pair of guide members 521a are provided corresponding to 515a and 515b and receive the pair of rotating shafts 515a and 515b so that the document tray 51 can rotate. , 521b of the multi-stage locking provided distributed between the ribs 510a, 510b corresponding to the ribs 510a, 510b The multi-stage locking mechanism 50 locks the document tray 51 so that it cannot be lifted when the document tray 51 is not lifted, and the document tray 51 is lifted to the maximum. In the second state, the document tray 51 is locked so as to hold the inclined state.

  With this configuration, the automatic document feeder 5 according to the present embodiment, for example, has a postcard size or a business card that is conveyed and read through the hard sheet H and U-turn conveyance path 56 that are conveyed and read through the straight conveyance path 56a. After a small-size document such as a document of a size is discharged onto the discharge tray 53, the document tray 51 is locked in the second state where the document tray 51 is lifted to the maximum (see FIGS. 13B and 15C). be able to. As a result, there is no need to always hold the document tray 51 by hand in order to secure a space for taking out small-size documents between the document tray 51 and the paper discharge tray 53. Therefore, in the present embodiment, a small-size original can be easily taken out with one hand while the original tray 51 is fully lifted and locked, and the work is improved when taking out the small-size original.

  In the automatic document feeder 5 according to the present embodiment, the multi-stage locking mechanism 50 includes a plurality of locking recesses 512a, 512b and 513a, 513b provided in the ribs 510a, 510b, and the ribs 510a. , 510b and a pair of protrusions 526a, 526b disposed on the guide members 521a, 521b side, and the protrusions 526a, 526b are urged in a direction to engage with the locking recesses 512a, 512b and 513a, 513b. Each of the plurality of locking recesses 512a, 512b and one of the locking recesses 512a, 513b when the document tray 51 is not lifted. By engaging the protrusions 526a and 526b, the document tray 51 is locked so as not to be lifted, and the document tray When one of the plurality of locking recesses 512a and 512b and the other locking recesses 513a and 513b is in the inclined state where 1 is raised to the maximum, the other locking recesses 513a and 513b are engaged with the corresponding protrusions 526a and 526b. By combining, the document tray 51 may be configured to lock so as to hold the inclined state.

  With this configuration, the automatic document feeder 5 according to the present embodiment allows the multi-stage locking mechanism 50 to engage the protrusions 526a and 526b with one of the locking recesses 512a and 512b and 513a and 513b. By rotating, the document tray 51 can be surely and easily locked in the inclined state in which the document tray 51 is lifted to the maximum. Also in this respect, the workability of taking out a small-size document can be improved.

  In the automatic document feeder 5 according to the present embodiment, each of the ribs 510a and 510b is formed in a fan shape on the lower side with respect to the rotation shafts 515a and 515b, and a plurality of bay-shaped recesses 514a and 514b are formed on the outer peripheral portion 511. The recesses 514a, 514b are formed as locking recesses 512a, 512b and 513a, 513b. The protrusions 526a, 526b are positioned below the ribs 510a, 510b, and the rotation shafts 515a, 515b, It is good also as a structure provided so that it may advance / retreat to the center direction of 515b.

  With this configuration, the automatic document feeder 5 according to the present embodiment engages the multi-stage locking mechanism 50 with the recesses 514a and 514b in which the protrusions 526a and 526b are the locking recesses 512a and 512b and 513a and 513b. Therefore, it is possible to maintain the downsizing and cost reduction, which are important for low-end machines.

  Further, in the automatic document feeder 5 according to the present embodiment, portions of the protrusions 526a and 526b that engage with the locking recesses 512a and 512b and 513a and 513b are formed in a hemispherical surface, and the locking recesses 512a and 512b. And the part which engages with protrusion 526a, 526b of 513a, 513b may be comprised by the taper-groove shape which becomes narrow gradually in the direction which the front opening by the side of protrusion 526a, 526b engages widely.

  With this configuration, the automatic document feeder 5 according to the present embodiment allows the protrusions 526a and 526b to be engaged with the locking recesses 512a and 512b and the document tray 51 when the document tray 51 is inclined to the maximum from the unopened state. It is easy to slide with respect to 513a and 513b, and the operation of moving to a desired lock position can be smoothly executed without hindering the rotation of the document tray 51.

  In addition, the image forming apparatus 1 according to the present embodiment includes the automatic document feeder 5 having the multi-stage locking mechanism 50, so that the vertical gap between the document tray 51 and the discharge tray 53 is small. Even when the automatic document feeder 5 having a function of reading a small-size document such as a hard sheet H is mounted, the discharged small-size document is placed after the document tray 51 is inclined to the maximum lifted position. It can be easily taken out with one hand, and the workability of taking out a small-size document can be improved.

  Although the embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present invention. For example, in the above embodiment, the multi-stage locking mechanism 50 is provided with two locking recesses 512a, 512b and 513a, 513b for engaging the protrusions 526a, 526b on the ribs 510a, 510b, respectively. Although the locking mechanism is used, a locking mechanism having a larger number of stages may be used.

  In the above-described embodiment, the multi-stage locking mechanism 50 has the protrusions 526a and 526b and the locking recesses 512a, 512b and 513a, 513b in the vertical direction (the direction perpendicular to the paper surface of the original sheet S). The projections 526a, 526b and the locking recesses 512a, 512b and 513a, 513b are engaged in the horizontal direction (direction perpendicular to the paper surface of the original sheet S). As good as

  In addition, the former configuration is more advantageous in terms of smoothness of sliding with respect to the locking recesses 512a, 512b and 513a, 513b of the protrusions 526a, 526b and operability for moving to the lock position.

  The present invention is useful in the field of an automatic document feeder used for a printer, a copying machine, a facsimile, and the like and an image forming apparatus provided with the automatic document feeder.

  As described above, according to the present invention, the document tray is locked so as not to be lifted when the document tray is not lifted, and the document tray is tilted when the document tray is tilted to the maximum. An automatic document feeder and an image forming apparatus that can lock a document tray at a predetermined angle and improve workability when taking out a small-sized document by providing a multi-stage locking mechanism that locks to maintain the state. Can be provided.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 3 Image forming part 4 Image reading part 5 ADF (automatic document feeder)
42 DF contact glass 42
50A Support means 50 Multi-stage locking mechanism 51 Document tray 53 Paper discharge trays 510a, 510b A pair of ribs 511 Outer peripheral portions 512a, 512b, 513a, 513b Locking recesses 514a, 514b Bay-shaped recesses 515a, 515b Rotating shaft 520 Document Conveyance path 521a, 521b Guide member 520c Base end part 525a, 525b Bearing part 526a, 526b Protrusion 527a, 527b Elastic member S Original sheet H Hard sheet

JP 2013-109229 A JP 09-086698 A JP 2012-249173 A

Claims (6)

An automatic document transport device that transports a document placed on a document tray to a predetermined reading position and discharges the document to a discharge tray disposed below the document tray,
A first state in which the document placed on the document tray can be transported and a second state in which the document tray has been lifted from the first state so as to be rotatable. An automatic document feeder comprising support means for supporting the posture of the document tray in the first state and the second state. The support means is
A pair of rotating shafts provided on a pair of ribs on both sides of the document in the main scanning direction of the document tray and projecting in the main scanning direction from the outside of the ribs;
A pair of guide members that support the document tray and that form a document conveyance path for conveying the document are provided on the inner wall surface of the document conveyance path corresponding to the pair of rotation shafts, and the document tray rotates. A pair of bearing portions for receiving the pair of rotating shafts so as to be capable of;
2. The multi-stage locking mechanism distributed between the pair of ribs and portions corresponding to the ribs of the pair of guide members. Automatic document feeder. The multi-stage locking mechanism includes a plurality of locking recesses provided on the ribs, a pair of protrusions disposed on the pair of guide members corresponding to the ribs, and the protrusions. An elastic member biasing in a direction to engage with the locking recess,
In the first state, one of the plurality of locking recesses engages with each of the corresponding protrusions to lock the document tray from being lifted, and In the second state, the other one of the plurality of locking recesses engages with each of the corresponding protrusions, so that the document tray is lifted to the maximum. The automatic document feeder according to claim 2, wherein the automatic document feeder is configured to be locked so as to maintain an inclined state. Each of the ribs is formed in a fan shape on the lower side with respect to the rotating shaft, a plurality of bay-shaped recesses are formed on the outer periphery, and the recesses constitute the locking recesses,
4. The automatic document feeder according to claim 3, wherein the protrusion is positioned below each of the ribs and is provided so as to advance and retreat in the center direction of the rotation shaft.   A portion of the projection that engages with the locking recess is formed in a hemispherical surface, and a portion of the locking recess that engages with the projection gradually tapers in a direction in which the projection-side opening is engaged deeply and deeply. 5. The automatic document feeder according to claim 3, wherein the automatic document feeder is configured in a groove shape.   An image forming apparatus comprising the automatic document feeder according to any one of claims 1 to 5.

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