JP2011136804A - Sheet feeding device and image processing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent jamming by confirming that a stacking plate which stacks sheet is in a normal posture where the stacking plate dose not inclined to perform sheet feeding. <P>SOLUTION: When the sheet of the stacking plate 20 is empty, the stacking plate 20 descends to the lowest position. When the stacking plate 20 reached the lowest position, a distance measuring sensor 33 which is a posture detection unit detects whether the stacking plate is horizontal in the normal posture or is inclined in an abnormal posture. When the stacking plate 20 is in the abnormal posture, the stacking plate moves up and down to correct the posture. A correcting action is repeated until the stacking plate 20 is to be in the normal posture. When the stacking plate 20 is in the normal posture, the sheet can be refilled. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a paper feeding device that can accommodate a large volume of paper so that the paper can be supplied to an image processing apparatus.

  2. Description of the Related Art As a paper feeding device that supplies paper to an image processing apparatus, there is a large capacity paper feeding tray that can accommodate large capacity paper. In this sheet feeding tray, a stacking plate for stacking a large amount of sheets is provided, the stacking plate is suspended by a plurality of wires, and the stacking plate moves up and down along the guide plate. When the stacking plate rises to the paper feeding position, paper can be fed to the image processing apparatus. When the number of sheets on the stacking plate decreases as the paper is fed, the stacking plate is pulled up.

  When the paper runs out, the paper feed tray is pulled out for replenishment, and the stacking plate is lowered to its lowest position by its own weight. When the paper is replenished to the stacking plate and the paper feed tray is pushed back, the stacking plate rises again to the paper feed position.

  By the way, the loading plate moves up and down in a horizontal posture. However, when the stacking plate descends, if it comes into contact with the guide plate, the stacking plate assumes an inclined posture and descends to the lowest position as it is. When a sheet is stacked on the stacking plate, the sheet is stacked on the stacking plate in an inclined state. Even if the stacking plate rises in an inclined position, the sheets do not come into a horizontal position because the sheets come into contact with the guide plate or the like or receive frictional resistance between the sheets.

  When the stacking plate in the inclined and abnormal posture is raised to the paper feeding position, the position of the stacked paper is deviated from that in the normal posture in the horizontal state. If paper is fed in this state, the paper cannot be fed normally and a jam occurs.

  Patent Document 1 includes a detector for detecting the position of the uppermost sheet stacked on the stacking plate and a detector for detecting that the uppermost sheet has reached the upper limit position in the large-capacity paper feed tray. It has been described. However, it is not detected whether the loading plate is in a horizontal normal posture or an inclined abnormal posture.

JP 2005-247537 A

  As described above, if it is not detected that the stacking plate is in the inclined posture, the inclined sheet is fed, which causes a jam. Therefore, in view of the above, an object of the present invention is to provide a paper feeding device that can prevent the occurrence of a jam by enabling paper feeding from a stacking plate in a normal posture that is not inclined.

  The present invention includes a stacking plate on which sheets are stacked, an elevating unit that raises and lowers the stacking plate, an attitude detection unit that detects the attitude of the stacking plate, and a control unit that controls the operation of the elevating unit for paper feeding. It is a thing. The posture detection unit detects whether the loading plate is in a normal posture that is not inclined or is in an abnormal posture that is inclined when there is no sheet on the loading plate.

  When a stacking plate on which no sheet is stacked is in a normal posture, the sheet is in a horizontal state even if the sheet is stacked on the stacking plate. Therefore, jamming does not occur even when paper is fed. When the loading plate is in an abnormal posture, the posture detector detects that it is in an abnormal posture. Therefore, by preventing the sheet from being replenished in this posture, the sheet can be prevented from being fed in an inclined state.

  The stacking plate is moved up and down between the lowest position when replenishing paper and a paper feeding position higher than this position, and the posture detection unit detects the posture of the loading plate when the stacking plate is at the lowest position. To do. At the lowest position, sheets are stacked on the stacking plate and replenished. Therefore, at this position, if the stacking plate is in a normal posture, the stacked sheets cannot be tilted as the stacking plate rises.

  When it is detected that the loading plate is in an inclined abnormal posture, the control unit performs a correction operation to raise and lower the loading plate so that the loading plate is in a normal posture. And a control part performs correction operation | movement until a loading board becomes a normal attitude | position. By the correction operation, the stacking plate can be automatically returned from the abnormal posture to the normal posture. That is, it is possible to prevent the sheet from being replenished to the stacking plate in an abnormal posture.

  The posture detection unit detects the posture of the stacking plate while the stacking plate on which the sheets are stacked rises from the lowest position to the paper feeding position. If an abnormal posture is detected while the loading plate is raised, the control unit performs a correction operation.

  Even if sheets are stacked while the stacking plate is in a normal posture, if the sheets are stacked one after the other, the stacking plate may be tilted while the stacking plate is raised, resulting in an abnormal posture. Therefore, by detecting the posture while the stacking plate is rising, it is possible to immediately detect the abnormality and cope with the abnormal posture before feeding.

  The control unit notifies this abnormality when the loading plate is in an abnormal posture after the correction operation. When the abnormal posture of the loading plate is not resolved, a notification is given. As a result, the paper is not fed in an abnormal posture, and the user can be encouraged to take measures such as reloading the paper.

  According to the present invention, since it can be detected that the stacking plate is in an abnormal posture, it is possible to prevent replenishment of sheets to the stacking plate in the abnormal posture. Therefore, paper is not fed from the loading plate in an abnormal posture, and jamming can be prevented. Even if the loading plate is in an abnormal posture, the loading plate can be automatically returned to the normal posture by performing the correction operation. Thereby, paper feeding can be performed normally.

1 is an overall configuration diagram of a digital multi-function peripheral having a large-capacity paper feed tray according to the present invention. Schematic diagram of the main parts of a large capacity tray Control block diagram for large-capacity paper feed tray A diagram for explaining that a loading plate not loaded with paper is in an abnormal posture A diagram for explaining that the loading plate loaded with paper is in an abnormal posture Diagram showing the posture detection unit The figure which shows another attitude | position detection part Flow chart of corrective action when empty stacking board is lowered Flow chart of corrective action when stacking plate loaded with paper rises

  FIG. 1 shows an image processing apparatus provided with the sheet feeding device of this embodiment. The image processing apparatus is a digital multi-function peripheral 1 and includes two sheet feeding apparatuses 400 and 500 together with a post-processing apparatus 300. Although not shown, the digital multi-function peripheral 1 includes a scanner using a CCD (Charge Coupled Device). The scanner reads a document as an RGB (R: red, G: green, B: blue) bitmap image having a predetermined resolution, and inputs image data.

  The digital multi-function peripheral 1 selectively performs multi-color and single-color image formation by electrophotography based on image information input via a network or the like, and records the formed image on a sheet. The digital multi-function peripheral 1 includes an image forming unit 106, a paper storage unit 107, and a paper transport unit 108.

  The image forming unit 106 includes an exposure unit 110, an intermediate transfer belt 111, image forming stations 112A to 112D, and a secondary transfer roller 114. Image forming stations 112 </ b> A to 112 </ b> D are arranged in a row between the intermediate transfer belt 111 and the exposure unit 110.

  Each of the image forming stations 112 </ b> A to 112 </ b> D forms an image based on the image information of each of the four hues including cyan, magenta, and yellow, which are three subtractive primary colors obtained by color separation of a color image. I do.

  The black image forming station 112A includes a photosensitive drum 101A, a developing unit 102A, a charging roller 103, a primary transfer roller 104, a cleaning unit 105, and the like.

  The charging roller 103 is a contact-type charger that uniformly charges the surface of the photosensitive drum 101A to a predetermined potential. Instead of the charging roller 103, a contact-type charger using a charging brush or a contact-type charger using a charging charger can be used. The exposure unit 110 includes a light source such as a semiconductor laser, a polygon mirror, a reflection mirror, and the like. The photosensitive drum 101A is irradiated with image light based on the black image information from the exposure unit 110, and an electrostatic latent image corresponding to the image information of the black hue is formed.

  The developing unit 102A supplies black toner to the surface of the photosensitive drum 101A on which the electrostatic latent image is formed, and develops the electrostatic latent image into a toner image. The cleaning unit 104 collects toner remaining on the surface of the photosensitive drum 101A.

  The intermediate transfer belt 111 forms a loop-shaped movement path. The intermediate transfer belt 111 passes between the photosensitive drum 101A and the primary transfer roller 104 in the lower movement path.

  The primary transfer roller 104 is applied with a primary transfer bias having a polarity opposite to the charging polarity of the toner by constant voltage control. The toner image formed on the photosensitive drum 101 </ b> A is transferred to the outer peripheral surface of the intermediate transfer belt 111.

  Each of the image forming stations 112B, 112C, and 112D for each hue of cyan, magenta, and yellow is configured in the same manner as the image forming station 112A. However, the image forming stations 112B, 112C, and 112D are irradiated from the exposure unit 110 with image light modulated by image information of each hue of cyan, magenta, and yellow. Each of the developing units 102B, 102C, and 102D supplies toners of cyan, magenta, and yellow hues to the photosensitive drums 101B, 101C, and 101D.

  As a result, toner images of hues of cyan, magenta, and yellow are formed on the photosensitive drums 101B, 101C, and 101D, respectively.

  When image information of only a part of the hues of yellow, magenta, cyan, and black is input, an electrostatic latent image is displayed in only part of the four image forming stations corresponding to the hue of the input image information. And a toner image are formed. For example, when a monochrome image is formed, an electrostatic latent image and a toner image are formed only at the black image forming station 112 A, and only the black developer image is transferred to the outer peripheral surface of the intermediate transfer belt 111.

  At the time of full-color image formation, electrostatic latent image formation and toner image formation are performed in all of the four image forming stations 112A, 112B, 112C, and 112D. Yellow, magenta, cyan, and black toner images are sequentially superimposed and transferred onto the outer peripheral surface of the intermediate transfer belt 111. Transfer of the toner image onto the outer peripheral surface of the intermediate transfer belt 111 corresponds to image preparation in the image forming unit 106.

  The toner image transferred to the outer peripheral surface of the intermediate transfer belt 111 is conveyed to a position facing the secondary transfer roller 114 by the rotation of the intermediate transfer belt 111. The secondary transfer roller 114 is in pressure contact with the outer peripheral surface of the intermediate transfer belt 111 with a predetermined nip pressure. A position where the intermediate transfer belt 111 and the secondary transfer roller 114 face each other is an image forming position 130 where an image is formed on a sheet.

  The paper storage unit 107 includes paper feed cassettes 116 </ b> A and 116 </ b> B and a manual feed tray 117 that each store a plurality of sheets of a single type. In addition, the digital multi-function peripheral 1 is optionally provided with paper feeding devices 400 and 500 as external paper storage units.

  The paper feeding device 400 is disposed below the digital multifunction peripheral 1 and includes paper feeding cassettes 116C and 116D therein. The paper feeding device 500 is disposed on the side surface of the digital multi-function peripheral 1 and stores a large amount of a single type of plural sheets. The paper feeding device 500 is a large capacity paper feeding tray and is a paper feeding device according to the present invention.

  In the paper transport unit 108, a first paper transport path 131 is formed from the paper feed cassettes 116 </ b> A and 116 </ b> B via the image forming position 130 to the post-processing device 300 installed on the upper surface of the digital multifunction peripheral 1. Pickup rollers 121A and 121B, paper feed rollers 122A and 122B, registration rollers 132, a fixing unit 133, a fourth transport roller, a first paper discharge roller 134, and the like are arranged in the first paper transport path 131.

  In the paper transport unit 108, a second paper transport path 135 that connects the manual tray 117 to the upstream side of the registration roller 132 in the paper transport direction of the first paper transport path 131 is formed.

  Further, the sheet conveying unit 108 is in communication with the upstream side of the registration roller 132 in the sheet conveying direction of the first sheet conveying path 131 between the fixing unit 133 of the first sheet conveying path 131 and the first paper discharge roller. A third paper transport path 136 is formed. The third paper conveyance path 136, which is a double-sided conveyance path, conveys a single-sided image-formed sheet that is switchback-conveyed by reversing the first paper discharge roller when a double-sided image is formed on both sides of the paper.

  The paper transport unit 108 is also formed with a fifth paper transport path 137 that connects the paper feeding device 500 to the first paper transport path 131. The paper feeding cassettes 116 </ b> C and 116 </ b> D in the paper feeding device 400 are connected to the first paper feeding path 131 via a sixth paper feeding path 138 provided in the paper feeding device 400.

  The sheets supplied from the sheet storage unit 107 and the sheet feeding devices 400 and 500 are conveyed through the first sheet conveyance path 131 and receive the transfer of the toner image from the intermediate transfer belt 111 when passing through the image forming position 130. . Further, when forming a double-sided image, the sheet on which the toner image has been transferred is conveyed in a switchback manner by the reversal of the first discharge roller, and is conveyed again to the first sheet conveying path 131 via the third sheet conveying path 136. . Then, the sheet on which the one-sided image has been formed receives the transfer of the toner image from the intermediate transfer belt 111 on the other side when passing through the image forming position 130.

  The registration rollers 132 arranged in the first paper transport path 131 are provided from the paper storage unit 107 (paper feed cassettes 116 </ b> A and 116 </ b> B, manual feed tray 117), the paper feeder 400, the paper feeder 500, or the third paper transport path 136. When the leading edge of the conveyed paper arrives, the rotation is stopped.

  The registration roller 132 rotates at the timing when the leading edge of the toner image attached to the intermediate transfer belt 111 reaches the image forming position 130 when the leading edge of the paper that has passed the registration roller 132 reaches the image forming position 130. To start.

  As a result, the sheet is conveyed in the first sheet conveying path 131 by the registration roller 132 so that the leading end thereof faces the leading end of the toner image at the image forming position 130. Note that the registration roller 132 also has a function of correcting the oblique feeding of the paper by contacting the leading edge of the paper while the rotation is stopped.

  The sheet on which the toner image is transferred at the image forming position 130 is guided to the fixing unit 133. The fixing unit 133 includes a heating roller 133A that has been heated to the toner melting temperature, and a pressure roller 133B that is in pressure contact with the heating roller 133A with a predetermined nip pressure. The sheet is heated and pressurized when passing through the fixing unit 133, and is discharged to the post-processing apparatus 300 in a state where the toner image is fixed on the surface.

  At the image forming position 130, all of the toner image adhering to the peripheral surface of the intermediate transfer belt 111 should be transferred to the sheet. However. Some may remain on the intermediate transfer belt 111. Further, the toner image attached to the peripheral surface of the intermediate transfer belt 111 may pass through the image forming position 130 without being transferred to the paper by the processing described later. The toner remaining on the intermediate transfer belt 111 after passing through the image forming position 130 is collected by the cleaning unit 105.

  The post-processing device 300 loads the paper discharged from the option delivery port of the digital multifunction peripheral 1 into the device, performs each post-processing, and stacks the paper on the paper discharge tray. Post-processing includes stapling of paper, discharging to a specified paper discharge tray among a plurality of paper discharge trays, and offsetting the discharge position on the paper discharge tray.

  A large-capacity paper feed tray, which is a paper feeding device 500 according to the present invention, includes a mounting table 10 that stores paper and a paper feeding unit 11 that feeds paper. The mounting table 10 is housed in a cabinet (not shown), guided by a slide rail, and movable in the front-rear direction. When a door is provided on the front side of the cabinet and the door is opened, the moved mounting table 10 is taken in and out of the cabinet.

  As shown in FIG. 2, the mounting table 10 includes a stacking plate 20 on which sheets are stacked, and an elevating unit 21 that lifts and lowers the stacking plate 20. The stacking plate 20 is a flat and rectangular tray. The elevating unit 21 includes a plurality of wires 22, a pulley 23, a take-up roller 24, and a lift motor 25.

  One end of each of the four wires 22 is attached to the stacking plate 20, the other end is attached to the take-up roller 24, and each wire 22 is hung on a pulley 23. The loading plate 20 is suspended by four wires 22 and supported in a horizontal state.

  As shown in FIG. 3, the lift motor 25 is driven and controlled by the control unit 26. The control unit 26 controls the entire digital multi-function peripheral 1 and controls the operation of the elevating unit 21 together with the operation of the paper feeding unit 11 during paper feeding.

  When the lift motor 25 is driven, the take-up roller 24 rotates, the four wires 22 are taken up simultaneously, and the stacking plate 20 is raised. The lift motor 25 can be rotated forward and backward, and when the winding roller 24 rotates forward, the wire 22 is pulled up and the stacking plate 20 is raised while being kept in a horizontal posture. When the winding roller 24 rotates in the reverse direction, the wires 22 are fed out simultaneously, and the stacking plate 20 is lowered while being maintained in a horizontal posture. When the stacking plate 20 is lowered, the stacking plate 20 may be lowered by its own weight after the take-up roller 24 is rotated in the reverse direction by the lift motor 25.

  A recess 27 is formed on the side surface of the stacking plate 20 in the left-right direction, and a guide plate (not shown) is provided opposite to the recess 27. The guide plate is provided in the vertical direction and guides the sheets stacked on the stacking plate 20 so as not to be displaced in the horizontal direction.

  When paper is replenished to the stacking plate 20, the lift motor 25 is driven and the stacking plate 20 is raised. A sheet sensor 30 for detecting the position of the uppermost sheet is provided, and when the sensor 30 detects that the uppermost sheet has been fed, the control unit 26 displays a lift motor. 25 is stopped. While the loading plate 20 is raised, the loading plate 20 is maintained in a horizontal posture.

  When the paper feed unit 11 having a pickup roller, a paper feed roller, and a separation roller is operated according to a command from the control unit 26, the paper is supplied to the image forming unit 106 one by one from the topmost paper. When all the sheets on the stacking plate 20 are supplied, the sheet sensor 30 detects that there is no sheet. In the digital multi-function peripheral 1, a paper out is notified. Instead of the paper sensor 30, a sensor for detecting the presence or absence of paper on the stacking plate 20 may be provided.

  The user opens the door of the large-capacity paper feed tray to replenish paper and pulls out the mounting table 10. At this time, the stacking plate 20 is lowered to the lowest position when the paper is replenished. A position detection sensor 31 that detects the stacking plate 20 at the lowest position is provided. The position detection sensor 31 is a known sensor such as a limit switch or an optical switch.

  Here, when the empty stacking plate 20 descends, as shown in FIG. 4, when the stacking plate 20 is shaken by vibration or the like and contacts the guide plate, the descending stacking plate 20 is tilted. If the stacking plate 20 is lowered to the lowest position, the stacking plate 20 stops in an inclined posture. When the loading plate 20 is greatly inclined, the user notices the inclination of the loading plate 20 and corrects the posture of the loading plate 20. However, when the inclination of the stacking plate 20 is small, the user replenishes the paper without noticing.

  When the user stacks sheets with the stacking plate 20 tilted, the stacked sheets are shifted along the tilt of the stacking plate 20. The sheet contacts the wall surface or guide plate of the mounting table 10. When the stacking plate 20 is lifted in such a state, the sheet is lifted while being displaced, and the offset sheet is not restored. If the stacking plate 20 in the inclined posture reaches the paper feeding position and paper feeding is performed in a state where the paper is tilted, a jam may occur.

  Further, even when the stacking plate 20 is in a horizontal posture at the lowest position, as shown in FIG. 5, the sheets may be stacked while being shifted in the middle, and the sheets may be stacked while being shifted in one direction. When the stacking plate 20 rises in this state, the center of gravity of the stacking plate 20 on which the paper is loaded is shifted, so that the stacking plate 20 tilts, or the paper contacts the wall surface of the guide plate or the mounting table 10 and rises. Resistance is added to 20 and the loading plate 20 tilts. In the paper feeding position, the stacking plate 20 is inclined. If paper is fed while the paper is tilted, a jam may occur.

  Therefore, in order to prevent paper feeding from being performed while the loading plate 20 is inclined, a posture detection unit 32 that detects the posture of the loading plate 20 is provided. The posture detection unit 32 detects whether the loading plate 20 is in a normal posture that is not inclined or whether the loading plate 20 is in an abnormal posture that is inclined. When the posture detection unit 32 detects the stacking plate 20 in the abnormal posture, the control unit 26 controls the operation of the elevating unit 21 so that the stacking plate 20 assumes a normal posture which is a horizontal posture. That is, the control unit 26 performs a correction operation to raise and lower the stacking plate 20 by rotating the lift motor 25 forward and backward.

  The posture detection unit 32 is a distance measuring sensor 33 as shown in FIG. The distance measuring sensors 33 are provided on the bottom surface of the mounting table 10, and the four distance measuring sensors 33 are arranged so as to face the four corners of the stacking plate 20. Each distance measuring sensor 33 measures the distance to the stacking plate 20. Thereby, the attitude | position detection part 32 can detect whether the stacking board 20 in the lowest position is in a normal attitude | position or an abnormal attitude | position. Further, the posture detection unit 32 can also detect whether the loading plate 20 being lifted / lowered is in a normal posture or an abnormal posture.

  The control unit 26 determines the posture of the stacking plate 20 based on the output from each distance measuring sensor 33. That is, the control unit 26 determines that the posture is normal when the distances from the distance measuring sensors 33 to the stacking plates 20 at the four corners are the same, and determines that the posture is abnormal when any one of the detected distances is different.

  As another posture detection unit 32, an acceleration sensor 34 may be used as shown in FIG. The acceleration sensor 34 is attached to the back surface of the stacking plate 20. Since the loading plate 20 is supported at four points by the four wires 22, the acceleration sensor 34 is disposed at a position equidistant from the attachment position of each wire 22. By using a biaxial acceleration sensor as the acceleration sensor 34, the inclination in two directions can be detected. When the stacking plate 20 tilts, the acceleration sensor 34 detects the direction of the tilt. Based on the output of the acceleration sensor 34, the control unit 26 determines whether the stacking plate 20 is in a normal posture or an abnormal posture.

  And the control part 26 controls operation | movement of the raising / lowering part 21 according to the attitude | position of the detected loading board 20. FIG. When the stacking plate 20 is in a normal posture, the control unit 26 performs a normal lifting operation. When the loading plate 20 is in an abnormal posture, the control unit 26 performs a correction operation so that the loading plate 20 is returned from the abnormal posture to the normal posture. As the correction operation, the stacking plate 20 is moved up and down. The loading plate is repeatedly raised and lowered until the loading plate 20 assumes a normal posture. When the loading plate is corrected to a normal posture, a normal lifting operation is performed.

  The control unit 26 determines the posture of the stacking plate 20 when there is no sheet on the stacking plate 20. In particular, when the stacking plate 20 is at the lowest position for replenishing paper, the control unit 26 determines the posture of the stacking plate 20. Further, after the sheets are stacked on the stacking plate 20, the control unit 26 determines the posture of the stacking plate 20 while the stacking plate 20 rises from the lowest position to the paper feeding position.

  Next, a series of operations from replenishing paper to starting feeding will be described. As shown in FIG. 8, when the paper in the large-capacity paper feed tray becomes empty, the user replenishes the paper. When the paper sensor 30 detects that there is no paper on the stacking plate 20, the control unit 26 detects that the door is opened (S1). The control unit 26 drives the lift motor 25 to lower the stacking plate 20. The stacking plate 20 is lowered (S2). At this point, the user cannot open the door.

  When the stacking plate 20 is lowered to the lowest position and the position detection sensor 31 detects the lowest position of the stacking plate (S3), the posture detection unit 32 detects the posture of the stacking plate 20. Based on the output from the posture detection unit 32, the control unit 26 determines whether the stacking plate 20 is in a normal posture or an abnormal posture (S4).

  When the stacking plate 20 is in an abnormal posture, the control unit 26 performs a correction operation. That is, the control unit 20 performs forward / reverse rotation of the lift motor 25 according to a preset sequence. The stacking plate 20 is lowered to a lowest position after being raised by a certain amount (S5) (S2, 3). The posture of the stacking plate 20 is detected, and the control unit 26 determines whether the stacking plate 20 is in a normal posture (S4). The control part 26 repeats raising / lowering of the stacking board 20 until it becomes a normal attitude | position. Further, when an abnormal posture of the stacking plate 20 is detected at the lowest position, the control unit 26 notifies the abnormality.

  In S4, if the control part 26 confirms that the stacking board 20 exists in a normal attitude | position, it will allow opening and closing of a door (S6). That is, the door is locked, and the control unit 26 releases the lock. The user can open the door and replenish paper. The user stacks sheets on the stacking plate 20 at the lowest position. When the paper supply is completed, the user closes the door. Thus, if the stacking plate 20 is in an abnormal posture, the door is not unlocked. For this reason, it is possible to prevent paper from being replenished with respect to the stacking plate 20 in an abnormal posture.

  As shown in FIG. 9, the control unit 26 drives the lift motor 25 when detecting that the door is closed (S <b> 10). The stacking plate 20 on which the sheets are stacked rises (S11). The posture detection unit 32 detects the posture of the stacking plate 20 that is rising, and the control unit 26 determines the posture of the stacking plate 20 (S12).

  When the stacking plate 20 is in an abnormal posture, the control unit 26 performs a correction operation. The control unit 26 drives and controls the lift motor 25 so that the stacking plate 20 is lowered by a certain amount (S13). Thereafter, the lift motor 25 is driven and controlled so as to raise the stacking plate 20 by a certain amount (S11). The control part 26 repeats raising / lowering of the stacking board 20 until it becomes a normal attitude | position. Therefore, the abnormal posture of the stacking plate 20 can be resolved before feeding.

  When it is detected that the stacking plate 20 is in the normal posture, the control unit 26 raises the stacking plate 20 to the paper feeding position. When the sheet sensor 30 detects that the stacking plate 20 has reached the sheet feeding position (S14), the control unit 26 stops the lift motor 26 and confirms the normal posture of the stacking plate 20, and then the sheet feeding unit. Is set in a standby state and waits in a state where paper can be fed (S15).

  By the way, even when the correction operation is performed a predetermined number of times on the stacking plate 20 on which sheets are stacked, the abnormal posture of the stacking plate 20 is not eliminated, or when the stacking plate 20 on which sheets are stacked reaches the paper feed position. When an abnormal posture is detected, the control unit 26 notifies a paper stacking abnormality. At this time, the control unit 26 prohibits the paper feeding operation. This prompts the user to reload the sheets, and the user manually corrects the abnormal posture of the stacking plate 20.

  As described above, even when the stacking plate 20 is in an abnormal posture, the stacking plate 20 can be returned to the normal posture by performing the correcting operation. The paper is in a normal state, and normal paper feeding is performed. In addition, by preventing the sheet from being replenished in an abnormal posture, it is possible to prevent the sheet from being fed in an inclined state. Therefore, the occurrence of jam can be prevented.

  In addition, this invention is not limited to the said embodiment, Of course, many corrections and changes can be added to the said embodiment within the scope of the present invention. When the sheet becomes empty, the stacking plate is lowered to the lowest position. During this lowering, the posture of the stacking plate on which the sheet is not stacked may be detected and the correction operation may be performed.

  As the correction operation, the loading plate has repeatedly raised and lowered by a certain amount, but it may continue to rise or fall until the loading plate is in a normal posture. In the above embodiment, the correction operation is automatically performed. However, the posture of the stacking plate may be corrected manually. When the abnormality of the loading plate is notified, the user opens the door so that the inclined loading plate becomes horizontal. When it is detected that the stacking plate is in a normal posture, the operation of the large capacity tray is resumed.

DESCRIPTION OF SYMBOLS 10 Mounting stand 11 Paper feed part 20 Loading board 21 Lifting part 22 Wire 23 Pulley 24 Winding roller 25 Lift motor 26 Control part 30 Paper sensor 31 Position detection sensor 32 Attitude detection part 33 Distance sensor 34 Acceleration sensor

Claims (8)

A posture detection unit comprising a loading plate for loading paper, a lifting unit for moving the loading plate up and down, a posture detection unit for detecting the posture of the loading plate, and a control unit for controlling the operation of the lifting unit for paper feeding Is a sheet feeding device that detects whether the loading plate is in a normal posture that is not inclined or an abnormal posture that is inclined when there is no paper on the loading plate. The stacking plate is moved up and down between the lowest position when replenishing paper and a paper feeding position higher than this position, and the posture detection unit detects the posture of the loading plate when the stacking plate is at the lowest position. The sheet feeding device according to claim 1, wherein: 3. The feeding device according to claim 1, wherein when the loading plate is detected to be in an abnormal posture, the control unit performs a correction operation to raise and lower the loading plate so that the loading plate is in a normal posture. Paper device. The paper feeding device according to claim 3, wherein the control unit performs a correction operation until the loading plate is in a normal posture. The paper feed according to any one of claims 2 to 4, wherein the posture detection unit detects the posture of the loading plate while the loading plate on which the paper is loaded rises from the lowest position to the paper feeding position. apparatus. 6. The sheet feeding device according to claim 5, wherein when an abnormal posture is detected while the stacking plate is raised, the control unit performs a correcting operation. The paper feeding device according to claim 5 or 6, wherein the controller notifies the abnormality when the stacking plate is in an abnormal posture after the correction operation. An image processing apparatus comprising the paper feeding device according to claim 1.

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