JP2020203771A - Sheet feeding device, automatic document conveying device and image forming device - Google Patents

Abstract

To provide a sheet feeding device capable of easily reducing adhesion force between sheets.SOLUTION: This device comprises: a document table 51 as a sheet loading member on which a document sheet bundle SA is loaded; a pickup roller 58 for feeding a document sheet S on a downstream side of the document table 51 in a sheet feeding direction Y; and an opposite guide plate 59 which faces the pickup roller 58 and guides the document sheet bundle SA. The document table 51 is provided over the whole area of a sheet loading part 80 in the sheet feeding direction Y. A position of the opposite guide plate 59 is fixed. The document table 51 is so constituted as to swing around a shaft 70 along a sheet width direction X. A drive motor 71, which swings the document table 51 so that an upstream side of the sheet bundle SA is curved vertically upward with the shaft 70 as a fulcrum, is provided. When the document sheet bundle SA is held by the pickup roller 58 and the opposite guide plate 59, the drive motor 71 is driven.SELECTED DRAWING: Figure 8

Description

The present invention relates to a sheet feeding device, an automatic document transporting device, and an image forming device.

The plurality of document bundles placed on the document table of the automatic document transfer device (hereinafter, also simply referred to as "ADF") are also in the feeding direction by a feeding member such as a pickup roller in order from the top or bottom document. It is fed in the transport direction. Since the manuscript to be fed out is in surface contact with the next manuscript, the next manuscript may be unintentionally fed out together.
As a known technique for preventing an unintentionally unwound document from being transported in the transport direction, the previous document is passed through a separation portion provided with a transport force in the transport direction and a blocking force acting in the opposite direction. There is known a technique for transporting the next document and preventing the transport of the next document.

However, in the case of a document with strong adhesion between the original papers (original sheets) of the original bundle, or a bundle of multiple originals connected to the next original one after another, so-called double feeding is performed in which the next original cannot be blocked by the separation portion. It may occur. It is already known that if the blocking force of the separation portion is set strongly in order to prevent double feeding, scratches such as turning over the tip of the document will occur.

Known techniques include levitation air, which is a technique for reducing the paper-to-paper adhesion force of a bundle of documents, which sends air between the document surfaces to reduce the adhesion force, and air supply, which is performed by suction air which adsorbs the top-level document. There is a technology to separate by feeding. These air feed separation technologies have the problems of increasing the size of the machine and generating noise, and also causing air to leak in an open space such as the current document table that emphasizes document settability, making it difficult to obtain the effect. ..

As a related technique, there is known a technique aimed at reducing bending of a set document formed by an angle formed by a document table and an auxiliary table, and non-feeding due to bending (for example, Patent Document 1). This is to alleviate bending of the set document by providing a convex portion as a support member for supporting the mounted document protruding upward from the document placing surface at the upstream end of the document table between the document table and the auxiliary table. It is a technology to do.

However, with the conventional sheet feeding technology as described above, there is a problem that the adhesion between sheets cannot be easily reduced.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a sheet feeding device capable of easily reducing the adhesion between sheets.

In order to achieve the above object, the present invention presents the sheet on a sheet mounting portion having a sheet mounting member on which the sheet bundle is mounted, and on the downstream side of the sheet mounting member in the sheet feeding direction. When the rotating member to be fed and the opposed guide member facing the rotating member and guiding the sheet bundle are provided, and the sheet bundle is sandwiched between the rotating member and the opposed guide member, the sheet is placed. It is in the seat feeder where the members move.

According to the present invention, it is possible to provide a sheet feeding device capable of easily reducing the adhesion between sheets.

It is an external perspective view of an example of the image forming apparatus which concerns on this invention. It is a schematic cross-sectional view which shows the outline of the internal structure of the image forming apparatus shown in FIG. It is a top view which shows around the document table of the automatic document transfer apparatus provided in the image forming apparatus shown in FIG. It is sectional drawing which shows an example of the automatic document transporting apparatus shown in FIG. FIG. 6 is a schematic cross-sectional view showing an outline of a U-turn transport path of the automatic document transport device and a DF scan unit of an image reader shown in FIG. It is a figure which shows the operation of the DF paper feed part of the automatic document transfer apparatus shown in FIG. It is a figure which shows the operation of the DF paper feed part of the automatic document transfer apparatus following FIG. It is a figure which shows the operation of the DF paper feed part of the automatic document transfer apparatus following FIG. It is a figure which shows the operation of the DF paper feed part of the automatic document transfer apparatus following FIG. It is a figure which shows the operation of the DF paper feed part of the automatic document transfer apparatus following FIG. It is an image diagram explaining the deviation of the original sheet when it is assumed that the curved part is a curved surface without considering the thickness of the original sheet and the rigidity by the material of the original sheet. It is an image diagram explaining the deviation of the original sheet when the thickness of the original sheet and the rigidity by the material of the original sheet are taken into consideration. It is sectional drawing which shows another example of the automatic document transfer apparatus provided in the image forming apparatus shown in FIG. It is a figure which shows the operation of the DF paper feed part of the automatic document transfer apparatus shown in FIG. It is a figure which shows the operation of the DF paper feed part of the automatic document transfer apparatus following FIG. It is a figure which shows the operation of the DF paper feed part of the automatic document transfer apparatus following FIG. It is sectional drawing which shows still another example of the automatic document transfer apparatus provided in the image forming apparatus shown in FIG. It is a figure which shows the operation of the DF paper feed part of the automatic document transfer apparatus shown in FIG. It is a figure which shows the operation of the DF paper feed part of the automatic document transfer apparatus following FIG. It is a figure which shows the operation of the DF paper feed part of the automatic document transfer apparatus following FIG. It is a schematic cross-sectional view of the modification of the automatic document transfer apparatus shown in FIG. FIG. 5 is a schematic plan view illustrating a configuration around a document table of another example of an automatic document transfer device provided in the image forming apparatus shown in FIG. 1. FIG. 22 is a partial cross-sectional view taken along the line AA of the DF paper feed section shown in FIG. FIG. 22 is a partial cross-sectional view taken along the line BB of the DF paper feed unit shown in FIG.

Hereinafter, embodiments of the present invention including examples will be described in detail with reference to the drawings. In each of the embodiments, components having the same function, shape, etc., that is, members, components, etc., will be described once unless there is a risk of confusion, and then the same reference numerals will be given to omit the description.

An example of the image forming apparatus according to the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is an external perspective view of the image forming apparatus according to the present invention, and FIG. 2 is a schematic cross-sectional view showing an outline of the internal configuration of the image forming apparatus shown in FIG.

The image forming apparatus 1 shown in FIGS. 1 and 2 is a color copier that forms an image by an electrophotographic method. The image forming apparatus 1 has an image forming portion 3 arranged in a substantially central portion of the apparatus main body 1A, and a paper feeding unit 2 arranged in a lower portion of the image forming portion 3. The image forming apparatus 1 includes an image reading unit 4 arranged on the upper part of the image forming unit 3 and an automatic document conveying device (hereinafter, abbreviated as "ADF") as a document conveying unit mounted on the upper part of the image reading unit 4. ) 5 and. The image reading unit 4 and the ADF 5 constitute an image reading device 6. The ADF includes a sheet feeding device according to the present invention. In addition, in the ADF 5 shown in FIG. 2, in order to simplify the figure, a part of the document feeding unit 35 (hereinafter, also referred to as “DF paper feeding unit”) as the sheet feeding device provided in the ADF 5 is configured. Is omitted.
In FIG. 1 and the like, Y is the sheet feeding direction (hereinafter, also referred to as “sub-scanning direction”) which is also the document conveying direction, and X is the sheet width direction (hereinafter, “main scanning direction”) orthogonal to the sheet feeding direction Y. Z also indicates the vertical direction (hereinafter, also referred to as “vertical direction” or “height direction”) orthogonal to the sheet feeding direction Y and the sheet width direction X, respectively.

The image forming apparatus 1 executes image processing or image forming processing based on the image data related to the image of the original document read by the image reading apparatus 6 or the image data transmitted from an external computer, and the scanned image. Can be recorded on a recording paper as a sheet-shaped recording medium, or an image file can be transferred and output. In the image forming apparatus 1, the operation of the image reading device 6 and the ADF 5 is controlled by the built-in control unit 30, and the operations of the image forming unit 3, the feeding unit 2, and the like are also controlled.

The image forming apparatus 1 includes a facsimile function capable of transmitting and receiving images, and has an image transmitting and receiving device 31 connected so as to be capable of transmitting and receiving to a computer such as an external personal computer or a host computer. The image transmission / reception device 31 has a function of transmitting an image of a document read by the image reading device 6 to a facsimile or an external computer which is a device of the other party. The image transmission / reception device 31 is also connected to the control unit 30 so as to be able to transmit / receive.

The image reading device 6 cooperates with the ADF 5 to read the original image during the automatic transfer of the original, the DF scanner mode (conveyed original reading mode), and the flat reading the image of the original placed on the flat contact glass 41. It is configured to be switchable to bed scanner mode (placed document reading mode).

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

In the DF scanner mode, the ADF 5 separates the original sheets one by one from the original sheet bundle placed and loaded on the sheet mounting table, that is, the original table 51 as the sheet mounting member, and carries them into the original transport path 52. The document is conveyed along the guide forming the document conveying path 52. Then, during the transport, the document sheet is sequentially and partially faced with the DF contact glass 42 on the upper surface side of the image reading unit 4 from the upstream side portion in the transport direction. That is, the image reading device 6 can exhibit the function of the DF scanner by sequentially reading the images on the document sheet conveyed by the ADF 5 on the DF contact glass 42 of the image reading unit 4.

The ADF 5 is attached to the rear portion (rear surface side portion) on the upper surface side of the apparatus main body 1A via an opening / closing mechanism such as a hinge (not shown). The ADF 5 may have an open position in which the flatbed contact glass 41 is open to the apparatus main body 1A and a closed position in which the document can be pressed against the flatbed contact glass 41.

The image forming unit 3 is configured to include a general electrophotographic image forming means, and is configured to be detachable from the exposure apparatus 7 and the apparatus main body 1A, and a plurality of process cartridges 8Y, 8M. It has 8C and 8K. The configurations of each process cartridge 8Y, 8M, 8C, 8K are the same except for the toner color of the developer used (yellow (Y), magenta (M), cyan (C), black (K), etc.). Therefore, the process cartridge 8Y will be described as a representative. The image forming unit 3 is not limited to the process cartridges 8Y, 8M, 8C, and 8K, and may have an apparatus configuration fixed to the image forming apparatus main body. Good.

The process cartridge 8Y includes a photoconductor drum 9Y as an image carrier, a charging device installed around the photoconductor drum 9Y, a developing device 10Y, and a cleaning device.
Further, in addition to the process cartridges 8Y, 8M, 8C, and 8K, the image forming unit 3 includes an intermediate transfer belt 11, a secondary transfer device 12, a fixing device 13, and the like.

The paper feed unit 2 separates and feeds the upper and lower paper feed cassettes 21 and 22 for storing recording papers having different paper sizes and the recording papers stored in the paper feed cassettes 21 and 22 one by one. It is provided with a sheet feeding means 23 made of rollers. Further, the paper feeding unit 2 includes a sheet transporting means 24 including various rollers for transporting the recording paper separated one by one by the sheet feeding means 23 to the secondary transfer position of the image forming unit 3.

The operation of the image forming apparatus 1 will be described. First, the surfaces of the photoconductor drums 9Y, 9M, 9C, and 9K are uniformly charged by the charging devices of the process cartridges 8Y, 8M, 8C, and 8K. On the other hand, in the image reading device 6, the image of the mounted original or the conveyed original is read by the first reading unit 45 and the second reading unit 69. Laser light is emitted from the exposure apparatus 7 toward the photoconductor drums 9Y, 9M, 9C, and 9K based on the image information decomposed by color by reading the original image. As a result, an electrostatic latent image is formed on each of the photoconductor drums 9Y, 9M, 9C, and 9K.

Next, by operating the developing devices 10Y, 10M, 10C, and 10K of the process cartridges 8Y, 8M, 8C, and 8K, the toner images (Y toner image, M toner image) color-coded on the photoconductor drums 9Y, 9M, 9C, and 9K. , C toner image, K toner image) is formed. These toner images are superimposed and transferred onto the intermediate transfer belt 11 by the primary transfer rollers provided so as to face the photoconductor drums 9Y, 9M, 9C, and 9K with the intermediate transfer belt 11 interposed therebetween, and are transferred in four colors. It becomes a toner image.

Further, almost at the same time as the start of the document reading operation, the paper feeding operation is started in the paper feeding unit 2. That is, one of the sheet feeding means 23 is selected and rotated, and the recording paper is fed from one of the plurality of paper feed cassettes 21 and 22. The fed recording paper is conveyed by the sheet conveying means 24 toward the secondary transfer device 12 of the image forming unit 3, and at this time, the secondary transfer device 12 superimposes and transfers the 4 on the intermediate transfer belt 11. The color toner images are collectively secondarily transferred to the recording paper to form a four-color image.

After that, the recording paper on which the four-color image is formed is conveyed to the fixing device 13 by the belt conveying device, and the toner of the unfixed color image transferred to the recording paper by the fixing device 13 is melted and 4 The color image of the color is fixed on the recording paper. After that, the recording paper on which the four color images are fixed is discharged to the output tray outside the machine by the output roller pair 14. Further, in the case of double-sided printing on the recording paper, the printing is re-fed to the secondary transfer device 12 via the reversing device and the refeeding device arranged at the lower left of the fixing device 13, and is printed on both sides of the recording paper. It is designed to form an image.

The detailed configuration and operation of the ADF 5 will be described with reference to FIGS. 3 to 10. FIG. 3 is a plan view showing the periphery of the document table of the ADF provided in the image forming apparatus shown in FIG. 1, and FIG. 4 is a cross-sectional view showing an example of the ADF shown in FIG. FIG. 5 is a schematic cross-sectional view showing an outline of the U-turn transport path of the ADF shown in FIG. 4 and the DF scanning unit of the image reader. FIG. 6 is a diagram showing the operation of the DF paper feed unit of the ADF shown in FIG. FIG. 7 is a diagram showing the operation of the DF paper feed unit of the ADF following FIG. 6, and FIG. 8 is a diagram showing the operation of the DF paper feed unit of the ADF following FIG. 9 is a diagram showing the operation of the DF paper feed unit of the ADF following FIG. 8, and FIG. 10 is a diagram showing the operation of the DF paper feed unit of the ADF following FIG.

As shown in FIG. 3, on the document table 51 as a sheet mounting member, the document sheet bundle SA or the document sheet S indicated by the two-dot chain line placed and set on the document table 51 is positioned in the sheet width direction X. A pair of left and right movable side guide plates 54 are mounted. These side guide plates 54 are configured to be relatively close to each other or separated from each other so that the center of the original table 51 and the original sheet bundle SA or the original sheet S in the width direction coincide with each other. The side guide plate 54 is not limited to the one described above, and one edge of the document sheet bundle SA or the document sheet S is brought into contact with one edge side of the document table 51 so that only the other edge side is contacted. It may be arranged so as to be movable.

As shown in FIGS. 2 and 3, the ADF 5 is covered with a cover 55 that can be opened and closed at least above the ADF 5. The cover 55 has a paper feed port 55a formed above the end of the document table 51 on the paper feed side so that the tip of the document sheet bundle SA enters the lower side of the cover 55. Further, the cover 55 covers the upper part of the tip portion of the document table 51 so that the tip portion of the document table 51 is housed inside the paper feed port 55a. Further, in the ADF 5, the main guide portion forming the transport passage of the document transport path 52 from the paper feed port 55a to the discharge port 56 is formed by ribs or the like formed on the cover 55 or the like.

As shown in FIG. 4, the document transport path 52 is arranged so as to face the pickup rollers 58 arranged on the downstream side of the sheet feeding direction Y from the paper feed port 55a shown in FIG. 2 and facing the pickup rollers 58. A DF having a facing guide plate 59, a paper feed roller 52a and a separation plate 60 arranged to face each other, and a set filler 57 and a shutter 61 arranged between the pickup roller 58 and the paper feed roller 52a. It is formed by a paper feed unit 35.
The DF paper feed unit 35 includes a document table 51 as the sheet mounting member described above.

The pickup roller 58 is a rotating member that feeds the document sheet S on the downstream side of the document table 51 in the sheet feeding direction Y. Further, the pickup roller 58 can be raised and lowered in the vertical direction Z, and is also a pickup member that picks up and feeds the original sheet S one by one from the original sheet bundle SA on the opposed guide plate 59 in the sheet feeding direction Y. The pickup roller 58 is configured to be movable up and down at a position where the document sheet S is brought out in contact with the document sheet S on the uppermost surface of the document sheet bundle SA and in a direction away from this position.

The facing guide plate 59 is a facing guide member that faces the pickup roller 58 and guides the document sheet bundle SA (see FIG. 5 and the like). Further, the facing guide plate 59 is a facing guide member whose position is fixed.

In FIG. 4, the sheet mounting portion 80 is a portion having a document table 51 on which a document sheet bundle SA (see FIG. 5 and the like) is placed. As shown in FIG. 4, the document table 51 as a sheet mounting member is provided over the entire area of the sheet mounting portion 80 in the sheet feeding direction Y.

The pickup roller 58 and the opposed guide plate 59 are sheet holding members, respectively, and form a sheet holding means for holding the downstream side of the document sheet bundle SA.
When the document sheet bundle SA is sandwiched between the pickup roller 58 and the facing guide plate 59, the document table 51 on which the document sheet bundle SA is placed moves. This detail will be described later in the operation.

The paper feed roller 52a and the separation plate 60 are separation means or separation units that separate the document sheets picked up and fed by the pickup roller 58 one by one.
The paper feed roller 52a of the separation means is not limited to this, and may be a paper feed belt type, and the separation plate 60 is not limited to this, and the separation plate 60 rotates in the direction opposite to the paper feed roller and the paper feed belt. It may be a roller type.

The set filler 57 has a set filler shaft 57a at the upstream end on the paper feed port 55a side with reference to the sheet feeding direction Y. The set filler 57 is configured to rotate, that is, swing within a predetermined angle range with the set filler shaft 57a as a fulcrum by placing the document sheet bundle SA. It has a tfiller 57. The set filler 57 is a sheet detection member that rotates clockwise in the drawing about the set filler shaft 57a when the tip of the original sheet bundle SA or the original sheet S abuts when the original sheet bundle is set by a user operation. .. The set filler shaft 57a is shown only in FIGS. 4 and 5 and omitted in other drawings in order to simplify the drawing.

The shutter 61 is a document sheet bundle regulating member that prevents the document sheet bundle SA or the document sheet S from being placed downstream of the sheet feeding direction Y from the abutting position when the tip of the document sheet bundle SA or the document sheet S abuts. , And a positioning member for positioning the tip of the document sheet bundle SA or the document sheet S.
The shutter 61 is rotatably provided at a regulation position for restricting the tip of the sheet and a regulation release position. The shutter 61 is provided by a shutter regulating member (not shown) rotatably provided at a regulation position that regulates the rotation of the shutter 61 in conjunction with the ascent and descent of the pickup roller 58 and a regulation release position that does not regulate the rotation. Movement is regulated. As such a shutter regulating member, for example, the shutter regulating member (101) disclosed in FIGS. 1 to 4 of Japanese Patent Application Laid-Open No. 2012-091885 proposed by the present applicant can be used.

The set filler 57 and the shutter 61 are arranged so as to be displaced in the sheet width direction X of the facing guide plate 59 so as not to interfere with each other. The set filler 57 and the shutter 61 are arranged so as not to interfere with the facing guide plate 59 or the like.
In the configuration of the DF paper feed unit 35, there is no shutter 61 and the original sheet can be inserted up to the arrangement position of the paper feed roller 52a, or a non-contact sensor is arranged on the original sheet instead of the set filler 57. It may be the one.

The document table 51 is configured to swing around a shaft 70 along the sheet width direction X. A drive motor 71 is provided as an example of a drive member that swings the document table 51 so that the upstream side of the document sheet bundle SA curves vertically upward with the shaft 70 as a fulcrum. The drive motor 71 is composed of a motor that can rotate in both forward and reverse directions, and is connected to a shaft 70 via a gear as an example of drive transmission means.
The drive motor 71 is driven at a predetermined timing. That is, when the downstream side of the document sheet bundle SA is sandwiched between the pickup roller 58 and the facing guide plate 59, the drive motor 71 swings the document table 51 so that the upstream side of the document sheet bundle SA bends vertically upward. Is driven.

The document table 51 may be integrally formed with the shaft 70 supported by the housing frame of the ADF 5, or may be formed separately from the shaft 70.
As shown in FIGS. 4 and 5, the shaft 70, which is the rotation fulcrum of the document table 51, is preferably near the upstream end of the adjacent facing guide plates 59 in the sheet feeding direction Y. Further, a plurality of shafts 70 may be provided at the downstream end of the document table 51 in the sheet feeding direction Y.

The ADF 5 is configured to separate the top-level original sheet S one by one from the original sheet bundle SA placed on the original table 51 and reversely convey it. That is, as shown in FIG. 5, downstream of the DF paper feed section 35 of the document transport path 52, the document sheet S separated into one sheet and carried into the U-shaped document transfer path 52 is inverted and DF contact is made. It is conveyed along the glass 42 so as to pass through a predetermined reading operation position Pd1 (specific working position) on the upper surface thereof.

The first reading unit 45 shown in the image reading device 6 of FIG. 2 includes an integrated optical scanning unit 47 and a housing 48 that is movably guided in the sheet feeding direction (sub-scanning direction) Y by a guide rod 46. It has a compression spring 49 that presses the body optical scanning unit 47 against the lower surface of the DF contact glass 42 or the flatbed contact glass 41. The first reading unit 45 is configured to be movable by having the above-mentioned components.
The first reading unit 45 is located between the reading position 47 (Pb) shown in FIG. 5 and the reading position 47 (Pa) shown in FIG. 5 from the reading position 47 (Pa) to the position on the right side surface of the device of the image reading unit 4. It can be moved and scanned.

As shown by the solid line in FIG. 2, the first scanning unit 45 is shown in the DF scanner mode in which the integrated optical scanning unit 47 is located on the lower surface of the DF contact glass 42 and reads one image of the conveyed original sheet. It is possible to move to the reading position 47 (Pb) shown in 5. Further, as shown by the broken line in FIG. 2, the first scanning unit 45 is of a flatbed scanner mode in which the integrated optical scanning unit 47 reads an image of a document sheet placed on the lower surface of the flatbed contact glass 41. It is sometimes possible to move to the reading position 47 (Pa) shown in FIG.
As shown in FIGS. 2 and 5, the ADF 5 is provided with a second reading unit 69 that reads the other image of the double-sided original sheet that is located on the upper surface of the DF contact glass 42 and is conveyed.

As shown in FIGS. 4 and 5, the document transport path 52 has a plurality of transport rollers 52b, 52c, 52d for transporting the document sheet S, and the paper ejection roller pair 52e, It has 52f. The number and location of the rollers for transporting and discharging paper are determined by the route setting conditions of the document transport path 52, the length in the sheet feeding direction Y, which is the minimum size of the document sheet S, and the like. It can be set arbitrarily according to.
The original sheet S after reading the image is discharged to the paper ejection tray 53 as the ejection unit by the paper ejection rollers 52e and 52f and collected.

The separation unit, the plurality of transfer rollers 52b, 52c, 52d, and the paper ejection roller pairs 52e, 52f together with a plurality of sensors arranged on the document transfer path 52 and a controller that executes transfer control based on their detection information. , The first transport unit 50 is configured. As a result, the first transport unit 50 carries in the original sheet S from above the original table 51, folds and conveys the original sheet S so as to pass through the reading operation position Pd1, and is a paper ejection area outside the original table 51. Paper is ejected into the stack area on the output tray 53. The controller may share functions with the control unit 30 shown in FIG.

The plurality of sensors described above are, for example, known paper feed appropriate position sensors, bump sensors, document width sensors, reading inlet sensors, resist sensors, ejection sensors, etc., and these sensors are on the upstream side of the document sheet S in the transport direction. It is arranged in order from the downstream side. Of course, the ordinary document sheet S is a PPC (plain paper copy: plain paper) or other easily curved sheet that can form an image recording surface.

When the original sheet bundle SA placed on the original table 51 is separated, conveyed, and ejected in order from the highest original sheet S, the U-turn conveying path described above is used. The advantage of the U-turn transfer path is that the paper can be ejected and stacked without disturbing the page surface order of the original sheets by reversing the transfer so as to be folded back, and the machine size in the sheet width direction X can be kept small. As a disadvantage, it is difficult to transport a document having a high bending rigidity, for example, a general thick paper such as a postcard or a business card.

Next, the operation of the DF paper feed unit 35 shown in FIG. 4 will be described with reference to FIGS. 6 to 10. In the examples described later, including one example shown in FIGS. 6 to 10, a plurality of document sheet bundles SA placed on the document table 51 have the same size in the sheet feeding direction Y for the sake of simplification of the description (FIG. 6). Then, a case consisting of the manuscript sheet S (three sheets) will be described. Specifically, the original sheet S located on the uppermost surface of the original sheet bundle SA is set as the uppermost original sheet S1, and the original sheet S placed in contact with the lower surface (back surface) of the uppermost original sheet S1. Is the next original sheet S2, and the original sheet S placed in contact with the lower surface (back surface) of the next original sheet S2 and the upper surface of the original table 51 is the lowest original sheet S3 (next next original sheet S3). Also called).
As shown in FIG. 6, in the initial state when the document is set, the document table 51 is in a substantially horizontal state on which the document sheet bundle SA is placed, and the pickup roller 58 is separated above the facing guide plate 59. In this state, a space is provided between the pickup roller 58 separated above the facing guide plate 59 and the facing guide surface of the facing guide plate 59. With this space, the document sheet bundle SA can be inserted through the paper feed port 55a (see FIG. 2) until the tip of the document sheet bundle SA abuts on the shutter 61 in the regulated position state of FIG. At the same time, the set filler 57 is rotated clockwise in the figure by the inserted document sheet bundle SA, and the document sheet bundle SA is inserted and placed by the abutting sensor (not shown) provided in the vicinity of the set filler 57. It is detected.

After the placement of the document sheet bundle SA is detected, the pickup roller 58 moves in the contact direction of the document sheet bundle SA and comes into contact with the uppermost document sheet S1 as shown in FIG. 7. Since the pickup roller 58 is driven and moved via a torque limiter (not shown), the pressing force of the pickup roller 58 against the uppermost document sheet S1 increases until the torque received by the torque limiter reaches the idling torque. .. In this state, the downstream side of the document sheet bundle SA is sandwiched between the facing guide plate 59 and the pickup roller 58.

When the downstream side of the document sheet bundle SA is sandwiched, as shown in FIG. 8, the document table 51 bends the document sheet bundle SA on the upstream side in the sheet feeding direction Y from the sandwiching position of the document sheet bundle SA. The drive motor 71 is driven so as to rotate counterclockwise. At this time, the drive motor 71 is driven so that the document table 51 rotates counterclockwise from the mounting position P1 in a substantially horizontal state to occupy the curved position P2 in a state where the downstream side of the document sheet bundle SA is sandwiched. Be controlled. In a state where the document table 51 is at the bending position P2, the document sheet bundle SA is curved to release the close contact state between the document sheets S and separate them. The details will be described with reference to FIGS. 11 and 12 described later.

As described above, the document table 51 rotates counterclockwise from the mounting position P1 indicated by the broken line on which the document sheet bundle SA is placed with the axis 70 as the center of rotation, and vertically rotates the document sheet bundle SA on the upstream side. The drive motor 71 is driven and controlled so as to occupy the curved position P2 indicated by the solid line that is curved upward. The placement position P1 is also the initial position of the document sheet bundle SA. That is, the document table 51 is configured to be movable and swingable between the mounting position P1 and the curved position P2 with the axis 70 as the center of rotation.

After the contact of the uppermost document sheet S1 of the pickup roller 58, the shutter 61 is released from the stopper function of receiving the abutting of the document sheet bundle SA and can rotate clockwise in FIG.

Then, as shown in FIG. 9, the document table 51 rotates clockwise and returns to the placement position P1. Then, the pickup roller 58 rotates so as to convey the uppermost document sheet S1 downstream in the sheet feeding direction Y. At this time, due to the pressing force of the pickup roller 58 against the uppermost document sheet S1 and the friction coefficient between the pickup roller 58 and the uppermost document sheet S1, the uppermost document sheet S1 has a conveying force downstream in the sheet feeding direction Y. To get. As a result, the document sheet S1 is conveyed so as to push away the shutter 61 and the set filler 57. Of the original sheet bundle SA, ideally only one uppermost original sheet S1 is conveyed downstream of the sheet feeding direction Y from the uppermost side.

However, the uppermost manuscript sheet S1 comes into contact with the next manuscript S sheet 2, and the next manuscript sheet S2 has the next manuscript sheet S3 (lowermost manuscript sheet 3) in contact with the facing guide surface of the facing guide plate 59. The contact continues like this. For this reason, in reality, even when transporting from the top-level side, double-feeding may occur in which lower-level documents are also transported.
In addition, as shown in FIG. 10, when the uppermost original sheet S1, the next original sheet S2, and the next original sheet S3 of the original sheet bundle SA are about to be double-fed by the rotary transfer of the pickup roller 58. The separation plate 60 acts as a resistance to the next original sheet S2 and the next original sheet S3 other than the uppermost original sheet S1 with respect to the rotation direction of the paper feed roller 52a, so that the next original sheet S2 and the next original Double feeding of the sheet S3 is further suppressed.

The original sheet S in which double feeding is suppressed is folded back and conveyed by a plurality of conveying rollers 52b, 52c, 52d constituting the U-turn conveying path shown in FIGS. 4 and 5, and is ejected by the paper ejection rollers pairs 52e and 52f. Paper is ejected into the stack area on the paper tray 53.

In the DF paper feed section 35, which is an example of the ADF 5 shown in FIGS. 4 to 10, the document table 51 at the mounting position P1 in FIG. 4 rotates counterclockwise with the axis 70 as a rotation fulcrum as shown in FIG. When the curved position P2 is occupied, a space is created above the paper ejection tray 53 in FIG. 4, so that the ejectability of the ejected original sheet S can be improved.

The double feed will be further described. Originals whose original sheets are made of paper and have high adhesion between the original papers generally tend to be double-fed. For example, a manuscript sheet made of coated paper has a processed surface and has high smoothness, and the manuscript sheets (manuscript paper) tend to be in close contact with each other, and double feeding tends to occur. However, even when the DF paper feed unit 35 conveys a document having a high adhesion between the original papers made of coated paper, as shown in FIG. 8, the document sheet bundle SA is curved and handled. It suppresses double feeding.

With reference to FIGS. 11 and 12, the document sheet misalignment and handling due to the curvature of the document sheet bundle SA described above will be described. In the figure, the broken line shows the original sheet before bending, and the solid line shows the original sheet after bending.
As illustrated in FIG. 8, the curved document sheet is sandwiched by the sheet sandwiching means (the document sheet bundle SA on the downstream side in the sheet feeding direction Y), whereas the sheet is fixed. The document sheet bundle SA on the upstream side in the feeding direction Y is open.
As shown in FIG. 11, if the curved portion is simply regarded as a curved surface without considering the thickness of the original sheet (for example, the thickness of the original paper) and the rigidity due to the material of the original sheet (for example, the original paper), it is located on the center of curvature side. The closer the document sheet S3 is, the shorter the radius of curvature and the shorter the arc length. The document sheet S1 farther from the center of curvature has a longer radius of curvature and a longer arc length. Since the length of the original sheet does not change, the original sheet deviation ΔL is formed on the adjacent contact surfaces of the original sheet S1, S2, and S3 of the original sheet bundle SA on the upstream side from the position curved with respect to the sandwiched position. Occurs. As a result, the close contact state between the document sheets is released.

Actually, as shown in FIG. 12, the thickness of the curved original sheet (for example, the original paper thickness) and the rigidity due to the material of the original sheet (for example, the original paper) cannot be ignored. Due to the thickness of the original sheet and the rigidity of the original sheet, the original sheet resists the bending motion of the original table and tries to maintain its original state. Further, the higher-order document sheet S1 in which the weight of the paper of the next document is not added does not follow the bending operation of the document table and is less likely to be curved. However, since the length of the original sheet does not change due to the difference between the upper and lower sides of the original sheet, each original sheet S1 of the original sheet bundle SA on the upstream side from the position curved with respect to the sandwiched position, The original sheet shifts on the adjacent contact surfaces of S2 and S3. As a result, the close contact state between the document sheets is released.

Therefore, according to the DF paper feed unit 35 shown in FIGS. 4 to 10, the document sheet bundle is curved to release the close contact state between the document sheets and separate them, so that the upper document sheet or the lower document sheet can be separated. It is possible to reduce the possibility that the next manuscript sheet is sent when feeding. Therefore, according to the DF paper feed unit 35, the adhesion between the original sheets of the original sheet bundle can be easily reduced, and the probability of a feeding error of the original sheets due to double feeding can be reduced.

The action / operation described with reference to FIGS. 11 and 12 in which the adjacent document sheets S are displaced due to the curvature of the document sheet bundle SA and the close contact state between the document sheets S is released is the DF paper feeding of the ADF5 described later. The same applies to each example of the section.

Next, the configuration and operation of the DF paper feed unit 35A in another example of the ADF 5 will be described with reference to FIGS. 13 to 16. FIG. 13 is a cross-sectional view showing another example of the ADF provided in the image forming apparatus shown in FIG. FIG. 14 is a diagram showing the operation of the DF paper feed unit of the ADF shown in FIG. 13, and FIG. 15 is a diagram showing the operation of the DF paper feed unit of the ADF following FIG. FIG. 16 is a diagram showing the operation of the DF paper feed unit of the ADF following FIG.

The DF paper feed unit 35A shown in FIGS. 13 to 16 differs from the DF paper feed unit 35 shown in FIGS. 4 to 10 in the following points. First, instead of the document table 51, a downstream document table 51b provided on the downstream side of the sheet feeding direction Y, which is divided into two via a shaft 51c, and an upstream side of the sheet feeding direction Y. The upstream document table 51a is provided as a sheet mounting member on which the document sheet bundle SA is mounted.
Secondly, instead of the pickup roller 58, a rotating roller 58A is provided as a rotating member whose position for feeding the document sheet S is fixed on the downstream side of the downstream document table 51b in the sheet feeding direction Y. ..
Thirdly, the upstream document table 51a as the sheet mounting member is provided so as to occupy a part of the upstream side of the sheet mounting portion 80 in the sheet feeding direction Y. Further, the difference is that the shutter 61 is removed.

The downstream side document table 51b is an opposed guide member that faces the rotating roller 58A and guides the document sheet bundle SA, and is also a pressing member that presses the document sheet bundle SA against the rotating roller 58A. The rotary roller 58A and the downstream side document table 51b are sheet sandwiching members, respectively, and form a sheet sandwiching means for sandwiching the downstream side of the document sheet bundle SA.

The downstream side document table 51b can move in the direction of contact with the rotary roller 58A and in the direction of separation via the document sheet bundle SA. That is, the downstream side document table 51b is configured to swing around a shaft 51c provided along the sheet width direction X and parallel to the sheet width direction X.
As an example in which the facing surface of the document table can move in the contacting / separating direction with respect to the rotating roller having a fixed position, for example, the pick arm (112) disclosed in Japanese Patent No. 6239061 can be mentioned. Examples of the means for detaching (pressurizing) the pick arm include those disclosed in Japanese Patent Application Laid-Open No. 2005-170651.

When the document sheet bundle SA is sandwiched between the rotating roller 58A and the downstream document table 51b, the upstream document table 51a is configured to move.

The upstream document table 51a is configured to swing around a shaft 51c along the sheet width direction X. The upstream side document table 51a is a movable and swingable sheet mounting member.
A drive motor 71 is provided as an example of a drive member that swings the upstream side document table 51a so that the upstream side of the document sheet bundle SA curves vertically upward with the shaft 51c as a fulcrum. When the downstream side of the document sheet bundle SA is sandwiched by the sheet sandwiching means, the drive motor 71 swings the upstream document table 51a so that the upstream side of the sheet bundle SA curves vertically upward with the shaft 51c as a fulcrum. Is driven.

The shaft 51c is formed so as to extend parallel to the sheet width direction X toward the front side of the paper surface and the back side of the paper surface of the upstream side document table 51a.
The upstream document table 51a may be integrally formed with the shaft 51c supported by the housing frame of the ADF5, or may be formed separately from the shaft 51c.

The drive motor 71 is composed of a motor that can rotate in both forward and reverse directions, and is connected to a shaft 51c via a gear as an example of drive transmission means. As shown in FIG. 16, the upstream document table 51a is configured to be movable and swingable between the mounting position P1 and the curved position P2 with the shaft 51c as the center of rotation.

In the drawing of the separation plate 60, the downstream side transport guide plate 64 installed near the right side is formed with a stepped portion 64a hanging so as to be adjacent to the left end portion of the downstream side document table 51b, and is similar to the shutter 61. Play the role of.

The operation will be described. In the initial state of the DF paper feed unit 35A shown in FIG. 13 when the document is set, as shown in FIGS. 13 and 14, the rotary roller 58A and the downstream document table 51b having a guide surface facing the rotary roller 58A There is a space between them. With this space, as shown in FIG. 14, the tip of the document sheet bundle SA is inserted through the paper feed port 55a (see FIG. 2) until it abuts on the step portion 64a adjacent to the downstream document table 51b. be able to. It is detected that the set filler 57 is rotated clockwise in the figure by the document sheet bundle SA inserted at the same time, and the document sheet bundle SA is inserted and placed.

After the placement of the document sheet bundle SA is detected, as shown in FIGS. 14 to 15, the downstream document table 51b rotates clockwise in the drawing with the shaft 51c as the rotation fulcrum, thereby moving to the rotating roller 58A. On the other hand, the uppermost document sheet S1 of the document sheet bundle SA comes into contact with the document sheet bundle SA. At this time, since the rotary roller 58A is driven via a torque limiter (not shown), the pressing force against the uppermost document sheet S1 against the rotary roller 58A increases until the torque received by the torque limiter reaches the idling torque. .. In this state, the downstream side of the document sheet bundle SA is sandwiched between the downstream side document table 51b and the rotary roller 58A.

After the document sheet bundle SA comes into contact with the rotating roller 58A, the downstream document table 51b becomes substantially parallel to the adjacent downstream transfer guide plate 64. As a result, the downstream side document table 51b gets over the step portion 64a that was abutted by the document sheet bundle SA, so that the rotating roller 58A causes the top-level document sheet S1 of the document sheet bundle SA, the next document sheet S2, and so on. The original sheet S3 is in a state where it can be sequentially fed to the separation unit.

When the downstream side of the document sheet bundle SA is pinched, as shown by the solid line in FIG. 16, the upstream side so as to bend the document sheet bundle SA on the upstream side in the sheet feeding direction Y from the sandwiching position of the document sheet bundle SA. The drive motor 71 is driven so that the document table 51a rotates counterclockwise. At this time, the drive motor 71 drives and controls the upstream side document table 51a so as to rotate counterclockwise from the mounting position P1 and occupy the bending position P2 that bends the upstream side document sheet bundle SA vertically upward. Will be done. In a state where the upstream side document table 51a is at the bending position P2, the document sheet bundle SA is curved to release the close contact state between the document sheets S and to handle them.

Next, as shown by the broken line in FIG. 16, the upstream document table 51a rotates clockwise and returns to the mounting position P1. Then, when the rotary roller 58A rotates so as to convey the uppermost document sheet S1 downstream in the sheet feeding direction Y, the pressing force of the rotary roller 58A against the uppermost document sheet S1 and the rotary roller 58A and the uppermost original sheet S1 Due to the coefficient of friction with the document sheet S1, the highest document sheet S1 obtains a conveying force downstream in the sheet feeding direction Y. As a result, the document sheet S1 is conveyed so as to push away the set filler 57. Subsequent operations are performed in the same manner as the operation of the DF paper feed unit 35 shown in FIG. 4 and the like.

According to the DF paper feed unit 35A of ADF5 shown in FIGS. 13 to 16, the document sheet bundle is curved so that the original sheets are in close contact with each other, as described above with reference to FIGS. 8 and 12 and the like. When the state is released and the upper manuscript sheet or the lower manuscript sheet is fed, it is possible to reduce that the next manuscript sheet is taken (double feed). Therefore, according to the DF paper feed unit 35A, the adhesion between the original sheets of the original sheet bundle can be easily reduced, and the probability of the original sheet feeding error due to double feeding can be reduced.

Even in the example of the DF paper feed unit 35A of the ADF5 shown in FIGS. 13 to 16, the upstream document table 51a at the mounting position of FIG. 13 is counterclockwise with the shaft 51c as the rotation fulcrum as shown in FIG. When the paper is rotated to occupy the curved position P2, a space is created above the paper ejection tray 53 in FIG. 13, so that the ease of taking out the paper ejection document sheet can be improved.

Next, the configuration and operation of the DF paper feed unit of still another example of the ADF will be described with reference to FIGS. 17 to 20. FIG. 17 is a cross-sectional view showing still another example of the ADF provided in the image forming apparatus shown in FIG. FIG. 18 is a diagram showing the operation of the DF paper feed unit of the ADF shown in FIG. 17, and FIG. 19 is a diagram showing the operation of the DF paper feed unit of the ADF following FIG. FIG. 20 is a diagram showing the operation of the DF paper feed unit of the ADF following FIG.
The DF paper feed unit 35B of the ADF 5 shown in FIG. 17 is roughly expressed by a method in which the DF paper feed unit 35 shown in FIG. 4 is upside down and fed from the lowest document sheet of the document table 51. is there.

The DF paper feed unit 35B shown in FIGS. 17 to 20 differs from the DF paper feed unit 35 shown in FIGS. 4 to 10 in the following points.
First, instead of the pickup roller 58, a rotating roller 58A as a fixed-position rotating member that feeds the document sheet S downstream of the document table 51 in the sheet feeding direction Y of the document sheet S is used. I have.
Secondly, instead of the opposed guide plate 59, an auxiliary pressing member 62 is provided as a pressing member for pressing the document sheet bundle SA against the rotating roller 58A. The auxiliary pressing member 62 is used to increase the pressing force between the rotating roller 58A and the document sheet, and is an example of the opposed guide member.
Third, the opposed guide plate 59 is provided with an opening (not shown) for bringing the rotary roller 58A into contact with the document sheet.

The rotary roller 58A is configured to be in contact with the lowermost document sheet S3 located on the lowermost surface of the document sheet bundle SA through an opening (not shown) provided in the opposed guide plate 59.
The auxiliary pressing member 62 is configured to swing around a shaft, and for example, a mechanism disclosed in Japanese Patent Application Laid-Open No. 2000-143001 is used.

The rotary roller 58A and the auxiliary pressing member 62 are sheet holding members, respectively, and form a sheet holding means for holding the downstream side of the document sheet bundle SA.
Then, when the document sheet bundle SA is sandwiched between the rotating roller 58A and the auxiliary pressing member 62, the document table 51 on which the document sheet bundle SA is placed moves.

The document table 51 as the sheet mounting member shown in FIG. 17 is provided over the entire area of the sheet mounting portion 80 in the sheet feeding direction Y. A drive motor 71 is provided as an example of a drive member that swings the document table 51 so that the upstream side of the document sheet bundle SA curves vertically upward with the shaft 70 as a fulcrum.
When the downstream side of the document sheet bundle SA is sandwiched between the rotating roller 58A and the auxiliary pressing member 62, the drive motor 71 uses the shaft 70 as a fulcrum so that the upstream side of the sheet bundle SA is curved in the vertically upward direction. Is driven to swing.

The operation will be described. As shown in FIG. 18, in the initial state when the document is set, the document sheet bundle SA can be inserted until the tip of the document sheet bundle SA abuts on the shutter 61 in the regulated position state of the figure. At the same time, the set filler 57 is rotated clockwise in the figure by the inserted document sheet bundle SA, and it is detected by the abutting sensor (not shown) that the document sheet bundle SA is inserted and placed.

After the placement of the document sheet bundle SA is detected, as shown in FIG. 19, the auxiliary pressing member 62 rotates counterclockwise in the drawing and comes into contact with the uppermost document sheet S1 to bring the lowermost document. A pressing force is generated between the seat S3 and the rotary roller 58A. In this state, the downstream side of the document sheet bundle SA is sandwiched between the rotary roller 58A and the auxiliary pressing member 62.

When the downstream side of the document sheet bundle SA is sandwiched between the rotating roller 58A and the auxiliary pressing member 62, the document is curved so as to bend the document sheet bundle SA on the upstream side in the sheet feeding direction Y from the sandwiching position of the document sheet bundle SA. The drive motor 71 is driven so that the table 51 rotates counterclockwise. At this time, in a state where the downstream side of the document sheet bundle SA is sandwiched, the document table 51 is rotated counterclockwise from the mounting position P1 and is shown by a solid line that bends the document sheet bundle SA on the upstream side vertically upward. The drive motor 71 is driven and controlled so as to occupy the curved position P2. In a state where the document table 51 is at the bending position P2, the document sheet bundle SA is curved to release the close contact state between the document sheets S and separate them.

After that, the document table 51 is returned to the placement position P1. With the document table 51 occupying the placement position P1, the rotary roller 58A is rotated in the direction of transporting the lowest document sheet S3 downstream of the sheet transport direction Y, so that the rotary roller 58A and the lowest document A frictional force is generated between the sheet S3 and the lowermost original sheet S3, which is transported downstream in the sheet transport direction Y.

Even in the example of the DF paper feed unit 35B of the ADF5 shown in FIG. 17, when the document table 51 at the mounting position P1 in FIG. 20 rotates counterclockwise with the axis 70 as the rotation fulcrum and occupies the curved position P2. Since a space is created above the output tray 53 of FIG. 17, the ease of taking out the output document sheet can be improved.

According to the DF paper feed unit 35B of the ADF5 shown in FIG. 17, the document sheet bundle is curved to solve the close contact state between the document sheets, as described above with reference to FIGS. 8 and 12 and the like. Therefore, it is possible to reduce the fact that the next original sheet is carried (double feed) when the upper original sheet or the lower original sheet is fed. Therefore, according to the DF paper feed unit 35B, the adhesion between the original sheets of the original sheet bundle can be easily reduced, and the probability of the original sheet feeding error due to double feeding can be reduced.

In the method of feeding paper from the lowest original sheet S3 as shown in FIG. 17, the remaining original sheet S is placed on the lowest original sheet S3 when the lowest original sheet S3 is conveyed. It has become. Therefore, the shutter 61 does not release the shutter by swinging, and by always providing a constant gap between the shutter 61 and the opposing guide plate 59, the upper original sheet is substantially blocked and the lower original sheet is passed through. There are many methods. Further, due to the load of the original sheet bundle SA, it may not be possible to convey even if the lowermost original sheet S3 is subjected to the conveying force. Therefore, the entire original table 51 or ADF5 is tilted to apply the load applied in the direction of gravity of the original sheet bundle. There are many methods to reduce it.

Next, using FIG. 21, the DF paper feed unit 35B, which is a method of feeding paper from the lowest document sheet S3 shown in FIG. 17, was applied to the ADF provided with the straight transfer path for performing the DF scan. A modified example will be described. FIG. 21 is a schematic cross-sectional view of a modified example of the ADF shown in FIG.
The ADF5 shown in FIG. 21 is a substantially straight document in which the lowest-level original sheet is separated one by one from the original sheet bundle placed on the original table 51 of the DF paper feed unit 35B shown in FIG. 17 and is not inverted. A transport path 52 is provided. The DF paper feed unit 35B shown in FIG. 17 is arranged so as to be inclined with respect to the document transport path 52 as a whole as shown in the figure. Then, the original sheet S separated and carried into the original transfer path 52 is conveyed along the DF contact glass 42, and the original is conveyed by the integrated optical scanning unit 47 and the second reading unit 69 via the DF contact glass 42. The image plane of the sheet S is read.

The document transport path 52 has a plurality of transport rollers 52b and 52c for such transport, and has paper ejection rollers 52d and 52e on the downstream side of the plurality of transport rollers 52b and 52c. The number and location of the rollers for transporting and discharging the paper can be arbitrarily set according to the route setting conditions of the document transport path 52, the length of the minimum size of the document sheet S in the document transport direction, and the like. Is.

Then, the original sheet S after reading the image is discharged to the paper ejection tray 53 by the paper ejection rollers 52d and 52e. When the DF paper feed unit 35B shown in FIG. 17, which separates, conveys, and ejects the lowermost original sheet from the original sheet bundle placed on the original table 51 in order, is applied, the straight transfer path is used. As an advantage of the straight transport path, by transporting the original sheet approximately straight without turning, the paper can be ejected and stacked without disturbing the page surface order of the original sheet, and the original with high bending rigidity can be easily conveyed. As a disadvantage, since the paper is fed from the lowest-ranked document, it may not be possible to feed even if the lowest-ranked document sheet S3 is fed due to the load of the document sheet bundle. Therefore, the original table 51 or the entire ADF 5 is tilted to reduce the load applied to the original sheet bundle in the gravity direction. Compared with the U-turn transfer path of FIG. 5, the straight transfer path tends to have a larger machine size in both the sheet width direction X and the vertical direction Z.

A configuration and operation of another example of the ADF provided in the image forming apparatus shown in FIG. 1 will be described with reference to FIGS. 22 to 24. FIG. 22 is a schematic plan view illustrating a configuration around a document table of another example of the ADF provided in the image forming apparatus shown in FIG. 1, and FIG. 23 is a partial cross-sectional view taken along the line AA of the DF paper feed section of FIG. 24 is a partial cross-sectional view taken along the line BB of the DF paper feed section of FIG. 22.
In the DF paper feed section 35C shown in FIGS. 22 to 24, as compared with the DF paper feed section 35 shown in FIG. 4, as shown in FIG. 23, the document table center portion 51d as the sheet mounting member has a sheet. The main difference is that the sheet mounting portion 80 is provided so as to occupy the middle portion in the feeding direction Y. That is, the document table central portion 51d as the sheet mounting member is not provided over the entire area of the sheet mounting portion 80 as in the document table 51 shown in FIG.

In the DF paper feed unit 35C, the original sheet S is fed from the original table central portion 51d on which the original sheet bundle SA is placed and the downstream side of the original sheet S from the original table central portion 51d in the sheet feeding direction Y. It includes a rotating member, a pickup roller 58 as a pickup member, and an opposing guide plate 59 as an opposed guide member that faces the pickup roller 58 and guides the document sheet bundle SA.

As shown in FIGS. 22 and 23, the document table central portion 51d provided at the substantially central portion of the document table 51 is configured to swing around an axis 73 parallel to the sheet width direction X. The shaft 73 is formed so as to extend parallel to the sheet width direction X toward the front side of a part of the paper surface of the document table 51 and the back side of the paper surface. An opening 51e for fitting the central portion 51d of the original document table is formed in a substantially central portion of the original document table 51.
The document table central portion 51d may be integrally formed with the shaft 73, or may be formed separately from the shaft 73 supported by a part of the document table 51.

A drive motor 74 is provided as an example of a drive member that swings the central portion 51d of the document table so that a part of the upstream side of the sheet bundle SA is curved vertically upward with the shaft 73 as a fulcrum. The drive motor 74 includes a motor that can rotate in both forward and reverse directions, and is connected to a shaft 73 via a gear as an example of drive transmission means.

The document table central portion 51d rotates counterclockwise from the mounting position P1 on which the document sheet bundle SA is placed with the axis 73 as the center of rotation, and bends the document sheet bundle SA on the upstream side vertically upward. The drive motor 74 is driven and controlled so as to occupy the position P2. That is, the document table central portion 51d is configured to be movable and swingable between the mounting position P1 and the curved position P2 with the shaft 73 as the center of rotation.

The operation will be described. The original sheet bundle SA is placed on the upper surface of the original table 51 including the central portion 51d of the original table at the placing position P1, the tips of the original sheet bundle SA are aligned by the shutter 61, and the set filler 57 and the abutting sensor (FIG. The placement of the document sheet bundle SA is detected by (not shown). After the placement of the document sheet bundle SA is detected, the pickup roller 58 descends and comes into contact with the uppermost document sheet of the document sheet bundle SA, and the pickup roller 58 and the facing guide plate 59 come into contact with the document sheet bundle SA. The downstream side of is pinched.

When the downstream side of the document sheet bundle SA is pinched, the drive motor 74 is driven so that the central portion 51d of the document table rotates counterclockwise. At this time, the drive motor 74 drives and controls the document table central portion 51d so as to rotate counterclockwise from the mounting position P1 and occupy the bending position P2 that bends the document sheet bundle SA on the upstream side vertically upward. Will be done.

Due to the rotational operation of the central portion 51d of the original table, the original sheet bundle SA placed on the central portion 51d of the original table has a mountain shape and a valley shape as shown in FIG. 23 downstream and upstream of the sheet feeding direction Y. Curved to form. At the same time, the document sheet bundle SA on the document table central portion 51d is curved so as to hang down in a mountain shape from the document table central portion 51d at both left and right ends in the sheet width direction X as shown in FIG. In this way, the original sheet bundle SA placed on the central portion 51d of the original table is dislocated and deformed in the sheet feeding direction Y and the sheet width direction X, so that the original sheet S in close contact with each other is displaced from each other. Is generated, the close contact state between the document sheets S is released, and the original sheets S are separated.
After that, the central portion 51d of the document table is returned to the placement position P1, the pickup roller 58 is rotated, and the document sheet S is fed.

As described above, according to the DF paper feed unit 35C of ADF5 shown in FIGS. 22 to 24, the original sheet bundle can be curved in multiple directions of the sheet feeding direction Y and the sheet width direction X. As a result, the close contact state between the document sheets is released, and it is possible to reduce the possibility that the next document sheet is carried (double feed) when the upper document sheet or the lower document sheet is fed.

In the description of the DF paper feed units 35, 35A, 35B of the ADF5 described above, the illustration of the side guide plate 54 arranged on the document table 51 or the upstream document table 51a and its description are omitted, but the document table 51 or the document table 51 or It swings together with the upstream side document table 51a.

The DF paper feed units 35, 35A, 35B, and 35C of the ADF5 described above are not limited to the above-described configuration and operation, and the drive motors 71 and 74 as drive members include the document tables 51 and 13 of FIGS. The upstream side document table 51a or the central portion 51d of the document table of FIG. 23 may be swung a plurality of times. The drive motors 71 and 74 swing the document table 51 of FIGS. 4 and 17, the upstream document table 51a of FIG. 13, or the central portion 51d of the document table of FIG. 23 a plurality of times, and then the pickup roller 58 and the rotary roller. The feeding of the manuscript sheet by 58A may be started.

The flat state of the document table is better from the viewpoint of ease of placing the document sheet. By repeating the bending operation of the document sheet bundle, the adhesion between the document sheets can be further reduced. However, even if the adhesion between the original sheets is reduced by the bending motion of the original sheet bundle, the weight of the original sheet itself cannot be eliminated, so that the friction with the next original sheet is not eliminated. Therefore, the initial state of the original table 51, the upstream original table 51a, or the central portion 51d of the original table should be a flat state in which the bundle of original sheets can be easily placed, and the bending operation may be repeated.

By repeating the bending operation a plurality of times as described above, the adhesion between the document sheets of the document sheet bundle can be further reduced.

The DF paper feed units 35, 35A, 35B, and 35C of the ADF5 described above are not limited to the above-described configuration and operation, and the documents of FIGS. 4 and 17 are formed so that the document sheet bundle SA is curved by the drive motors 71 and 74. The feeding of the original sheet S by the pickup roller 58 or the rotating roller 58A may be started in a state where the table 51, the upstream original table 51a of FIG. 13, or the central portion 51d of the original table of FIG. 23 is shaken. ..
That is, when the original sheet S is finally fed, the original table 51 in FIGS. 4 and 17, the upstream original table 51a in FIG. 13, or the central portion 51d of the original table in FIG. 23 occupies the curved position P2. (States as shown in FIGS. 8, 16, 20, and 23).
As a result, the pickup roller 58 or the rotating roller 58A and the initial contact surface of the document sheet bundle are slightly displaced, and the pickup roller 58 or the rotating roller 58A starts feeding at a contact surface different from the initial contact surface of the document sheet bundle. Will come to do.

In this way, the free fall of the document sheet can be improved from the initial contact surface between the pickup roller 58 or the rotary roller 58A and the document sheet bundle, or the friction between the document sheets due to bending can be reduced. ..

The DF paper feed units 35, 35A, 35B, and 35C of the ADF5 described above are not limited to the above-described configuration and operation, and when the drive motors 71 and 74 as drive members are driven, an impact is applied to the document sheet bundle. It may be given.
When the drive motors 71 and 74 are driven, the document table 51 in FIGS. 4 and 17, the upstream document table 51a in FIG. 13, or the central portion 51d of the document table in FIG. When returning to the position P1, the document sheet bundle is impacted.

As a method of giving an impact to the document sheet bundle, for example, when returning the document table from the curved position to the mounting position, the impact is given by strengthening the abutting against the positioning member set for positioning to the mounting position. The configuration can be mentioned. As a method of strengthening the abutting against the positioning member, it is possible to accelerate the driving speeds of the drive motors 71 and 74 when the document table returns to the mounting position.
By further applying an impact to the bending motion, the document sheets can be further moved and the adhesion between the document sheets can be reduced.

In the DF paper feed units 35, 35A, 35B, 35C of the ADF5 described above, the sheet mounting member (the original table 51 of FIGS. 4 and 17 and the upstream original table 51a of FIG. 13 or the central portion 51d of the original table of FIG. 23) It may be referred to as a "sheet bending member" in view of performing a peculiar operation of bending a bundle of original sheets on which the paper is placed. Further, the sheet mounting member (the document table 51 of FIGS. 4 and 17, the upstream document table 51a of FIG. 13, or the central portion 51d of the document table of FIG. 23) moves in a state where the document sheet bundle is placed and described above. In view of performing a peculiar operation, it may be referred to as a "moving member".

In the DF paper feed unit 35 shown in FIG. 4, the DF paper feed unit 35A shown in FIG. 13, the DF paper feed unit 35B shown in FIG. 17, and the DF paper feed unit 35C shown in FIG. 23, the document table 51 and the upstream When the side original table 51a or the central portion 51d of the original table occupies the bending position P2, the original sheet bundle SA is curved vertically upward, but it may be curved vertically downward.

That is, in the present invention, the sheet mounting member (manuscript table 51, upstream manuscript table 51a or manuscript table central portion 51d) may be moved or rocked so that the upstream side of the sheet bundle SA is curved in at least one direction. ..
The document table 51, the upstream document table 51a, or the central portion 51d of the document table is rotated counterclockwise from the mounting position P1 to occupy the curved position P2, and is rotated clockwise from the curved position P2 to be mounted. It is swung at an acute angle of rotation so as to occupy P1, but the present invention is not limited to this, and the original sheet bundle SA may be moved or swung at an obtuse angle within a range that does not damage it.

The drive system of the document table 51, the upstream document table 51a or the document table central portion 51d is such that the axes 70, 51c, 73 as rotation fulcrums via the drive motors 71, 74 as the drive source and the gears as the drive transmission means. It was a method of transmitting the drive to, but it is not limited to this. That is, a method of rotating each shaft 70, 51c, 73 from a drive source such as a motor via a belt connection, or a sheet mounting member other than each shaft 70, 51c, 73 (manuscript table 51, upstream manuscript table 51a, or A method may be used in which the cam is brought into contact with the document table central portion 51d) and the cam is driven from a drive source such as a motor or a solenoid to move the sheet mounting member (document table 51, upstream document table 51a or document table central portion 51d). ..

The pair of transport rollers 52b, 52c arranged adjacent to the downstream side of the paper feed rollers 52a of the DF paper feed units 35, 35A, 35B, 35C of each of the above examples are set at the drive timing of the pickup roller 58 or the rotary roller 58A. Correspondingly, it has a tip alignment function of abutting the tip of the paper-fed document sheet to correct skew transfer and pulling out and transporting the corrected document sheet.

Although the preferred embodiment of the present invention has been described above, the present invention is not limited to such a specific embodiment, and the present invention described in the claims unless otherwise specified in the above description. Various modifications and changes are possible within the scope of the above. For example, the technical items described in the above-described embodiments and examples may be appropriately combined.

The image forming apparatus to which the present invention can be applied is not limited to the color copying machine described above, and all known electrophotographic image forming apparatus (for example, a copying machine, a printer, a facsimile) capable of mounting an ADF or a sheet feeding device (for example, a copying machine, a printer, a facsimile). , Plotter or a multifunction device having these functions, etc.), and an image forming apparatus such as an inkjet recording apparatus and a printing machine including a stencil printing machine.

The sheet according to the present invention includes the above-mentioned manuscript sheet, plain paper, thick paper, coated paper, business cards, plastic films, and the like, and includes all transportable objects to be transported.

The sheet feeding device according to the present invention is not limited to the one applied to the above-mentioned ADF, but can also be applied to a paper feeding device such as the paper feeding unit 2 shown in FIG. Further, as the image forming apparatus according to the present invention, an image forming apparatus provided with either an ADF or a paper feeding device to which the sheet feeding device according to the present invention is applied, or a sheet feeding device according to the present invention is applied. It may be an image forming apparatus including both an ADF and a paper feeding device.

The effects appropriately described in the embodiments of the present invention merely list the most preferable effects arising from the present invention, and the effects according to the present invention are limited to those described in the embodiments of the present invention. It's not a thing.

1 Image forming device 2 Paper feeding unit 3 Image forming unit 4 Image reading unit 5 ADF (an example of automatic document transfer device)
6 Image readers 35, 35A, 35B, 35C DF paper feed unit (example of sheet feeder)
51 Manuscript table (an example of sheet mounting member)
51a Upstream document table (an example of sheet mounting member)
51b Downstream document table (an example of facing guide member and pressing member)
51c, 70, 73 Axis 51d Central part of document table (example of sheet mounting member)
52 Document transport path 52a Paper feed roller 53 Paper output tray 57 Set filler 58 Pickup roller (example of rotating member and pickup member)
58A rotating roller (an example of a rotating member with a fixed position)
59 Opposing guide plate (an example of opposing guide member and pressing member)
60 Separation plate 61 Shutter 62 Auxiliary pressing member (example of pressing member)
71, 74 Drive motor (example of drive member)
80 Sheet mounting part S Manuscript sheet (example of sheet)
SA manuscript sheet bundle (example of sheet bundle)
X Sheet width direction Y Sheet feeding direction Z Vertical direction

Japanese Unexamined Patent Publication No. 08-286437

Claims (12)

A sheet mounting portion having a sheet mounting member on which the sheet bundle is mounted,
On the downstream side of the sheet mounting member in the sheet feeding direction, the rotating member for feeding the sheet and the rotating member
An opposed guide member that faces the rotating member and guides the sheet bundle is provided.
A sheet feeding device in which the sheet mounting member moves when the sheet bundle is sandwiched between the rotating member and the opposed guide member. The rotating member has a fixed position and is fixed in position.
The sheet feeding device according to claim 1, wherein the opposed guide member is a pressing member that presses the sheet bundle against the rotating member. The position of the facing guide member is fixed, and the position is fixed.
The sheet feeding device according to claim 1, wherein the rotating member is a pickup member that presses the sheet bundle against the opposed guide member. The sheet feeding device according to any one of claims 1 to 3, wherein the sheet mounting member is provided over the entire area of the sheet mounting portion in the sheet feeding direction. The sheet mounting member according to any one of claims 1 to 3, wherein the sheet mounting member is provided so as to occupy a part of the upstream side of the sheet mounting portion in the sheet feeding direction. Sheet feeder. The sheet feeding member according to any one of claims 1 to 3, wherein the sheet mounting member is provided so as to occupy an intermediate portion of the sheet mounting portion in the sheet feeding direction. apparatus. The sheet mounting member is configured to swing around an axis along a sheet width direction orthogonal to the sheet feeding direction.
A drive member for swinging the seat mounting member so that the upstream side of the seat bundle in the seat feeding direction curves in at least one direction with the shaft as a fulcrum is provided.
The sheet feeding device according to any one of claims 1 to 6, wherein the driving member is driven when the sheet bundle is sandwiched between the rotating member and the opposing guide member. The seat feeding device according to claim 7, wherein the driving member swings the seat mounting member a plurality of times, and then the rotating member starts feeding the seat. The sheet feeding device according to claim 1, wherein the sheet feeding device is started by the rotating member in a state where the seat mounting member is moved. The sheet feeding device according to claim 1, wherein an impact is applied to the sheet bundle. The sheet feeding device according to any one of claims 1 to 10 is provided, and the sheet fed from the sheet feeding device is conveyed to an image reading unit that reads image information of the sheet. Automatic document transfer device. An image forming apparatus comprising either or both of the sheet feeding device according to any one of claims 1 to 10 and the automatic document conveying device according to claim 11.

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