JP2008303040A - Sheet feeder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet feeder which is miniaturized and capable of preventing a finger from being caught. <P>SOLUTION: The sheet feeder comprises a sheet stacking stand for stacking sheets and elevating them to a predetermined position, a sheet feeding means for feeding the highest sheet of a sheet bundle placed on the sheet stacking stand in the sheet feeder, and a sheet abnormal shape detection means for detecting any abnormal state of the fed sheets. The sheet abnormal shape detection means is movably supported above the sheet stacking stand. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a sheet feeding apparatus, and more particularly, to a sheet feeding apparatus that feeds a sheet used in an image reading apparatus, an image forming apparatus, and the like.

  2. Description of the Related Art Conventionally, a sheet feeding apparatus equipped in an apparatus main body such as an image reading apparatus or an image forming apparatus feeds sheets stacked on a sheet stacking table from a sheet stacking table by a pickup roller that is a sheet feeding unit. When the sheets are fed in an overlapping manner, the sheet is separated one by one by a downstream feeding roller and a separation roller pressed against the feeding roller and fed into the apparatus main body.

  The sheet stacking base is controlled to raise the sheet bundle according to the sheet stacking amount so that the uppermost sheet of the stacked sheet bundle always comes into contact with the pickup roller.

  The uppermost sheet of the sheet bundle fed by the pickup roller rotates so as to turn up around the portion bound during feeding, becomes a fold or tears, or the entire sheet bundle rotates. It may become a distorted shape. Even if the sheets are not bundled, this phenomenon may occur as a conveyance failure when static electricity is generated between the sheets and separation of the sheets becomes worse. For this reason, sheet jamming has occurred in the sheet feeding apparatus.

  Further, an image reading apparatus provided with such a sheet feeding apparatus in the apparatus main body may not be able to reliably read an image on a sheet. Further, an image forming apparatus provided with such a sheet feeding apparatus in the apparatus main body may not be able to reliably form an image on a sheet.

As a sheet feeding apparatus that addresses such a problem, a light emitting unit that emits light that is substantially parallel to the sheet stacking surface of the sheet stacking table as illustrated in FIG. 6 and intersects the sheet feeding direction, and a light emitting unit There is a sheet abnormal shape detecting means having a light receiving portion for receiving the light of the sheet, and detecting the jumping of the sheet due to the conveyance failure and stopping the conveyance (for example, see Patent Document 1).
JP 2004-182449 A

  However, in the known sheet feeding device, in order to detect an abnormal state of the fed sheet, it is necessary to dispose the sheet abnormal shape detecting means outside the maximum sheet width that can be stacked on the sheet stacking table. . In addition, the foldable sheet stacking base needs to prevent contact with the abnormal sheet shape detecting means during folding.

  Therefore, the abnormal sheet shape detecting means has to be arranged outside the sheet stacking table, which leads to an increase in the size of the apparatus main body as shown in FIG.

  An object of the present invention is to provide a sheet feeding device that has a sheet stacking table that moves up and down, and that has a sheet abnormal shape detecting unit that detects an abnormal shape of the stacked sheets, and is reduced in size. There is. It is another object of the present invention to provide a sheet feeding device that can prevent finger pinching between the rising sheet stacking table and the abnormal sheet shape detecting means.

  In order to achieve the above object, the sheet feeding apparatus according to claim 1 is provided outside the sheet width, a sheet stacking base, a sheet feeding means for feeding sheets on the sheet stacking base into the apparatus, and And an abnormal sheet shape detecting means for detecting an abnormal sheet feeding state, and the abnormal sheet shape detecting means is supported movably in a direction away from the sheet stacking table.

  According to the present invention, the abnormal sheet shape detecting means is supported so as to be movable away from the sheet stacking table, and the abnormal sheet shape detecting means pushed by the sheet stacking table when the sheet stacking table is folded is provided. Since it moves, it becomes possible to provide the sheet abnormal shape detecting means on the side of the sheet stacking base at a position where it does not protrude from the sheet stacking base, and the size of the apparatus can be reduced.

  Further, the abnormal sheet shape detecting means is supported so as to be movable or rotatable in the same direction as the rising direction of the sheet stacking table, and a finger or the like is sandwiched between the rising sheet stacking table and the abnormal sheet shape detecting means. However, since the abnormal sheet shape detecting means is retracted, problems such as injury and damage to the apparatus do not occur.

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

  First, an image reading apparatus provided with a sheet feeding apparatus according to an embodiment of the present invention will be described.

  FIG. 1 is a diagram schematically illustrating a configuration of an image reading apparatus including a sheet feeding device according to the present embodiment. FIG. 2 is a schematic diagram illustrating a configuration of a main part of the image reading apparatus in FIG. It is a schematic diagram shown.

  The image reading apparatus 200 includes an apparatus main body 201 and an opening / closing unit 202 that opens and closes during maintenance such as sheet jam processing. The document table 1 as a sheet stacking table is supported by the apparatus main body 201 so as to be rotatable about a shaft 1a, and is configured to be folded when the apparatus is not used, so that the size is reduced. Further, since the support member 203 described later is rotatable, further downsizing can be achieved if the support member 203 is disposed at a position where it comes into contact with the document table 1 when the document table 1 is folded. Then, a plurality of documents are stacked in an open state, and the document table drive motor 2 moves up and down by a mechanism (not shown). A restriction plate 50 for restricting the position of the stacked originals in the width direction is provided on the original table. The document detection sensor 3 detects the document on the document table 1. A pickup roller 4 as a sheet feeding unit feeds a sheet on the document table 1 from the document table 1. The pickup motor 5 rotates the pickup roller 4.

  The feed roller 6 is rotated by the feed motor 8 in a direction in which the document is conveyed downstream. The separation roller 7 always receives a rotational force for conveying the document upstream from the separation motor 9 via a slip clutch (not shown). However, when the number of documents is one, the separation roller 7 receives the document conveyance force and receives the document by the slip clutch. The feed roller 6 is allowed to follow and rotate. The separation roller 7 rotates in the direction of conveyance to the upstream side when a plurality of documents are fed, and conveys the document back to the upstream side.

  When the original is overlapped and fed into the nip between the feed roller 6 and the separation roller 7 by the action of feeding the original of the feed roller 6 to the downstream side and the action of returning the original of the separation roller 7 to the upstream side. The upper document is conveyed downstream, and the lower document is pushed back upstream, so that the overlapping documents are separated and conveyed. Therefore, the feed roller 6 and the separation roller 7 constitute a separation roller pair 6 and 7.

  The feed motor 8 rotates the feed roller 6. The separation motor 9 rotates the separation roller 7.

  The carry motor 10 drives each roller to be described later so as to carry the separated and conveyed document from the document reading position to the discharge position. Also, the conveyance speed can be changed according to the optimum speed for reading the original, the resolution of the original, and the like.

  The image reading unit 43 including the image reading sensors 14 and 15 reads a document and changes the scanning interval based on the document reading speed and resolution. The document discharge sensor 16 detects a document that has passed through the image reading unit 43 and reached the document discharge unit 44.

  The registration rollers 17 and 18 temporarily stop and restrict the document from being conveyed downstream to correct the skew of the document. The registration clutch 19 transmits the rotation of the conveyance motor 10 to the registration roller 18 or turns it off.

  The document transport rollers 20, 21, 22, and 23 transport the document F to the document discharge unit 44. The two guide plates, the upper guide plate 40 and the lower guide plate 41, hold the document F conveyed between the pair of separation rollers 6 and 7, the registration rollers 17 and 18, and the document conveyance rollers 20, 21, 22 and 23. invite.

  The pre-feed document sensor S1 detects the front end (downstream end) of the fed document. The post-feed document sensor S2 detects the trailing end (upstream end) of the fed document.

  The pre-registration sensor S3 detects a document that is disposed upstream of the registration rollers 17 and 18 and is fed. The post-registration sensor S4 detects a document that is disposed downstream of the registration rollers 17 and 18 and is fed.

  A document jumping detection sensor SS as a sheet abnormal shape detecting means for detecting an abnormal sheet feeding state detects a document jumping up on the document table 1.

  3 is a perspective view of the image reading apparatus in FIG. 1, and FIG. 4 is a side view of the sheet feeding apparatus in FIG. Reference sign SS-a indicates a light emitting unit constituted by a light emitting element such as an LED. Reference sign SS-b indicates a light receiving unit constituted by a light receiving element such as a light receiving sensor. These light emitting part and light receiving part are provided on the holding member 203. The holding member 203 of the light emitting unit SS-a and the light receiving unit SS-b is provided on the front surface of the opening / closing unit 202 outside the maximum document width (interval between the regulating plates 50) that can be stacked on the document table. These are urged in the direction of arrow A in FIG. 1 by urging means (not shown), and are supported on the rotation shaft SS-1 so as to be rotatable in the direction of arrow B. As a result, the flip-up detection sensor rotates and retracts even when it contacts the document table 1 when the document table 1 is folded, so that it is not necessary to dispose the document table 1 outside the document table 1 and the apparatus can be downsized. The document table drive motor 2 is controlled to raise the document table 1 to an optimum position according to the document stacking amount.

  The bounce detection sensor SS detects that the document has bounced when the light path from the light emitting unit SS-a to the light receiving unit SS-b is blocked. A line connecting the light emitting unit SS-a and the light receiving unit SS-b is substantially parallel to the document stacking surface 1a of the document table 1 and is substantially orthogonal to the conveyance direction of the document F. The control unit 45 controls not only the document feeder but also the entire image reading apparatus 200. For example, the controller 45 controls each motor based on the output signal from each sensor to control the rotation of each roller. The operations of the pickup roller 4 and the feed roller 6 are immediately stopped by the splash detection sensor, but the already fed sheets are discharged by the continuous operation of the transport rollers 22 and 23.

  It should be noted that the support member of the jump sensor is arranged so as to be shifted from the upper side to the outer side of the document table 1 and is separated from the document table 1 by the contact of the finger or the like with the support member from the lower side as described above. The present invention also includes a case where it is configured to be movable.

  FIG. 7 is a side view schematically showing a configuration around the pickup roller in FIG.

  In FIG. 7, a document F is placed on the document table 1. Reference numeral 81 denotes a document detection lever, 91 an arm that holds the pickup roller 4, 92 a document table drive mechanism that raises and lowers the document table, and 93 a conveyance guide that is locked to the main body. Reference numeral 3 denotes a document detection sensor made of a photo interrupter, and the displacement of the document detection lever 81 is detected when the light shielding portion 81a integrally formed or attached to the document detection lever 81 changes from a state of blocking light to a state of not blocking light.

  The document table 1 can be moved up and down by an elevating mechanism 92, and the document F is loaded on the document table 1 with the downstream end in the feeding direction in contact with the side wall of the conveyance guide 93 as shown in the figure. The

  The pickup roller 4 is held by an arm 91, and rotates by receiving the driving force of the pickup motor 5 by a driving transmission means (not shown) provided on the arm. Moreover, it protects so that a hand cannot be touched directly by the protection member 80 attached to the apparatus main body shown in FIG.

  The document detection lever 81 is located on the outer side in the rotational axis direction with respect to the light-shielding portion 81 a that shields the light beam from the document detection sensor (photo interrupter) 3 and the pickup roller 4, and can protrude from the outer peripheral portion of the pickup roller 4. In addition, a first detection unit 81b is provided in the vicinity of the protective member 80 for detecting by contacting the uppermost surface of the document F. The document detection lever 81 also has a second detection portion 81 c that can detect an obstacle formed or attached upstream from the central portion of the pickup roller 4. It is rotatably supported around a rotation shaft 81d arranged on the upstream side in the transport direction. Until the document table 1 is raised, the document detection lever 81 is supported by the protective member 10 at a predetermined position where the first detection portion 81b protrudes from the outer periphery of the pickup roller 4 as shown in FIG. When the document table 1 is raised and the uppermost surface of the document F reaches an appropriate height L, the first detection unit 81b of the document detection lever is slightly pushed up, so that the light is blocked by the light blocking unit 81a of the document detection lever. The original document detection sensor (photo interrupter) 3 is not shielded from light and enters a detection state.

  The control means (not shown) stops the lifting mechanism 92 in this state, and rotates the pickup roller 4 in the feeding direction to start feeding a plurality of sheets including the uppermost document into the image reading apparatus.

  As shown in FIGS. 10 and 11, the document detection lever 81 has a shape that covers a part of the upstream side of the center portion of the pickup roller, and each detection portion adjacent to both ends of the pickup roller. However, it extends to the vicinity of the upstream end portion of the protection member 80 and is integrally connected there.

  When the user raises the document table 1 and the user is alert and keeps the hand 82 on the document table 1 as shown in FIG. 8, the document table 1, the pickup roller 4 and the protection member 80 The second detection portion 81c of the document detection lever 81 is pushed up before the finger is sandwiched between them, and the document detection sensor is not shielded from light and enters a detection state. It is equivalent to the case where the upper surface of the original is reached to the upper limit height in a pseudo manner, and the original table 1 that has been continuously raised by the elevating mechanism 92 is stopped, so that the user can be prevented from feeling uncomfortable. As described above, the second detection portion is formed in such a size that the second detection portion can contact the user's finger before the first detection portion contacts the sheet.

  Further, since there is a part of the document detection lever in the vicinity of the end on the most upstream side in the transport direction of the protection member 80, when the hand is taken from the upstream side in the transport direction, the protection member 80 and the document or the document table 1 are not connected. It also has the effect of preventing finger pinching. Further, as shown in FIGS. 10 and 11, the document detection lever extends along the end of the pickup roller to the vicinity of the upstream end in the conveying direction of the protection member 80 so as to protrude from the outer periphery of the pickup roller. Therefore, it is possible to prevent finger pinching from the lateral direction indicated by the arrow Y in FIG.

  12 and 13 are a perspective view of the periphery of a pickup roller of another form and a perspective view of a document detection lever. In the illustrated embodiment, two pickup rollers 4 are arranged, or a groove is provided in the middle of the pickup roller 4, the first detection portion 83 b of the document detection lever 83 is sandwiched between the pickup rollers 4, and the pickup roller The document detection lever 83 is arranged so that the first detection portion 83 b protrudes from the outer peripheral portion of 4. A second detection portion 83 c is formed near the upstream end of the document detection lever 83, and a support shaft 83 d provided at the upstream end of the document detection lever 83 is rotatably supported by the protection member 80. . The light shielding portion 83 a is provided at the downstream end of the document detection lever 83. With this configuration, the configuration shown in FIG. 10 is the same, but the movement of the detection unit is enlarged and transmitted to the light shielding unit 83a, so that it is possible to accurately detect that the upper surface of the document has reached an appropriate height. . Further, it is possible to perform control such as quickly detecting a user's finger taken out from the upstream side to stop the document table from rising.

  Next, the operation of the image reading apparatus in this embodiment will be described.

  First, the operator loads a plurality of documents F on the document table 1. The operator manually moves the left and right document restricting plates 50 according to the size of the loaded document and regulates the position of the document in the width direction. A start signal is sent from the operation display unit 46 such as a liquid crystal panel with a touch panel to the control unit 45 by the operation of the operator. The operation display unit 46 displays a message that informs the operator of the abnormal state when it is detected that the document is bounced up or the curl amount is large. The control unit 45 sends an ascending signal to the document table driving motor 2 to raise the document table 1 and raise the document to the feeding position. When the raised document is detected by the document detection sensor 3, the control unit 45 stops the rotation of the document table driving motor 2 and stops the document table 1 from rising.

  Then, the control unit 45 starts the pickup motor 5. The pickup motor 5 rotates so that the document can be conveyed at a set speed, and rotates the pickup roller 4. When the number of documents stacked on the document table 1 decreases, the document detection sensor 3 cannot detect the document, so the control unit 45 moves the document table to the position where the document is detected by the document detection sensor. Raise 1

  Due to the rotation of the pickup roller 4, the uppermost document F1 among the plurality of documents F is conveyed to the pair of separation rollers 6 and 7 and is detected by the pre-feed document sensor S1.

  The control unit 45 controls the pickup motor 5 for a specified time or a specified number of pulses after the document F1 is detected by the pre-feed document sensor S1, and feeds the first document F1 by the pickup roller 4. To do. The fed document F1 is conveyed between the feed roller 6 and the separation roller 7. Here, when a plurality of documents are fed by the pickup roller 4, only the uppermost document F 1 is conveyed into the apparatus main body by the feed roller 6, and the remaining documents are upstream by the separation roller 7. Returned.

  As shown in FIG. 5A, when the corner of the document F is fixed to the document bundle by the staple SP1, the document F1 is positioned between the feed roller 6 and the separation roller 7 (see FIGS. 1 and 2). As shown in FIG. 5 (b), a part starts to jump up. This jumping occurs due to distortion generated between the portion where the document F1 is fixed by the staple SP1 and the portion fed by the pickup roller 4 and the feed roller 6. In particular, when the “Flip” is present in the document F1, it is prominent.

  A part of the document F1 that has been bounced up is detected by the bounce-up detection sensor SS. The control unit 45 stops the rotation of the pickup motor 5, the feed motor 8, and the separation motor 9 based on a signal from the splash detection sensor SS.

  Here, when the size of the document F loaded on the document table is small and the number of stacked sheets is small, a space is generated on both sides of the document restriction plate 50 of the document table 1. If the operator starts the document conveyance with the hand placed in this space, the operator's hand supports the jump detection sensor SS before the document table 1 is raised and the document detection sensor 3 detects the document. However, since the support member 203 is rotated and retracted in the direction of arrow B when pushed by the operator's hand, the operator's hand is not sandwiched between the document table 1 and the support member 203.

  The sheet feeding apparatus described in the present embodiment has been described using an image reading apparatus including the sheet feeding apparatus as an example. However, the sheet feeding apparatus can also be applied to an image forming apparatus and a sheet processing apparatus that have the same sheet feeding method. is there.

1 is a diagram schematically illustrating a configuration of an image reading apparatus including a sheet feeding apparatus according to an embodiment of the present invention. FIG. 2 is a schematic diagram schematically showing a configuration of a main part of the image reading apparatus in FIG. 1. FIG. 2 is a perspective view of the image reading apparatus in FIG. 1. FIG. 2 is a side view of the sheet feeding device in FIG. 1. 2A is a perspective view of a document bundle loaded on a document table, FIG. 3A is a perspective view of a document in which a corner portion of a front end is bound by a staple, and FIG. FIG. 6 is a perspective view of a document that has been bounced up during feeding. It is a perspective view of the conventional image reading apparatus. FIG. 2 is a side view schematically showing a configuration around a pickup roller in FIG. 1. FIG. 2 is a side view schematically showing a configuration around a pickup roller in FIG. 1. FIG. 2 is a front view schematically showing a configuration around a pickup roller in FIG. 1. It is a perspective view of the original document detection lever in FIG. FIG. 2 is a perspective view of the periphery of a pickup roller in FIG. 1. It is a perspective view of the periphery of the pick-up roller in another form. It is a perspective view of the original document detection lever in FIG.

Explanation of symbols

SS Bounce detection sensor SS-a Light emission portion SS-b of bounce detection sensor Light receiving portion SS-1 of bounce detection sensor Rotating shaft F Document F1 Topmost document 1 Document table 4 Pickup roller 5 Pickup motor 6 Feeding roller 7 Separating roller 50 Document restriction plate 200 Image reading apparatus 201 Main body 202 of image reading apparatus Opening / closing unit 203 of image reading apparatus Support member

Claims (2)

A sheet stacker;
Sheet feeding means for feeding sheets on the sheet stacking table into the apparatus;
An abnormal sheet shape detecting means that is provided outside the sheet width and detects an abnormal sheet feeding state;
The sheet feeding apparatus according to claim 1, wherein the abnormal sheet shape detecting means is supported so as to be movable away from the sheet stacking table. A driving means for raising the sheet stacking table;
2. The sheet feeding apparatus according to claim 1, wherein the abnormal sheet shape detecting means is supported so as to be movable in the substantially same direction as the ascending direction of the sheet stacking table, or is supported so as to be rotatable. .

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