JP2016124653A - Sheet feeder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet feeder capable of securely aligning sheets on a loading tray by a movable regulation plate of the sheet feeder, and preventing sheet feeding failure.SOLUTION: A sheet feeder comprises a movable regulation mechanism 49 for pressing and regulating one end part in a width direction of sheets on a loading tray 32. After the loading tray 32 is elevated to move the uppermost surface of the sheets to a feed-out position where the sheets are fed out by a feed-out roller 40, the feed-out roller 40 is moved from a contact position where it contacts the uppermost surface of the sheets to a retreat position where it is away from the uppermost surface. Accordingly, the sheets on the loading tray 32 can be aligned and sheet feeding failure can be prevented.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a sheet feeding device that feeds sheets, and more particularly to a configuration for aligning sheets placed on a stacking tray.

  2. Description of the Related Art Conventionally, a sheet feeding device that feeds a sheet to an image forming unit of an image forming apparatus such as a copying machine or a printer is known. In such a sheet feeding device, the sheets on the stacking tray are fed by a feeding roller, and the fed sheet is separated into one sheet by a separation unit including a sheet feeding roller and a separation member, and is fed to the image forming unit of the image forming apparatus. Paper is formed, and an image is formed on the sheet by the image forming unit.

  Among these types of paper feeders, in an apparatus that handles a large number of sheets, a stackable tray that can be raised and lowered is provided by raising the stacking tray and bringing the uppermost surface of the sheet on the stacking tray into contact with the peripheral surface of the feeding roller. Devices equipped are known. In the sheet feeding device having the stacking tray, the stacking tray is raised by a motor so that the uppermost surface of the sheet is brought into contact with the feeding roller, and the sheet is fed at a position where the feeding roller is pushed up by a predetermined amount (sending position). is there. The sheet feeder is provided with sheet upper surface detecting means for detecting that the uppermost surface of the sheet placed on the stacking tray has reached a predetermined delivery position. The sheet upper surface detecting means is provided on the upper surface of the sheet. When this is detected, the motor is controlled to stop.

  For example, as shown in Patent Document 1, the sheet upper surface detecting means includes a detection flag provided on a rotatable bracket that supports a feeding roller, and a photo sensor fixed to the sheet feeding device body. is there. In the detection of the sheet upper surface position by the sheet upper surface detection means, the stacking tray is raised and brought into contact with the feeding roller on which the uppermost surface of the sheet is suspended by its own weight. As a result, the feed roller is pushed up, the bracket pivotally supported so as to rotate, and the detection flag moves upward. When the detection flag detects the photo sensor, it is detected that the uppermost surface of the sheet has reached the delivery position.

  On the other hand, since the size of the sheet in the storage of the paper feeder varies with respect to the specified size, the side regulating plate is provided so as to be slightly larger than the sheet width of the specified size. For this reason, there is a type in which a movable side regulating plate is provided to regulate the widthwise end of the stacked sheets around the sending position and prevent skew feeding of the sheets during feeding (for example, patents) Reference 2). The movable side regulating plate is provided on one end side in the width direction of the sheet, and a fixed side regulating plate is provided on the other end side in the width direction of the sheet. The movable side restricting plate is disposed so that the uppermost surface of the movable side restricting plate restricts several dozen sheets on the upper side of the stacked sheets at the sending position, and is elastically supported via a spring. The movable side regulating plate is configured to urge the upper sheet of the stacked sheets and press the other end of the sheet against the fixed side regulating plate to align the sheets.

JP-A-3-21136 JP 2001-192124 A

  However, when the movable side restricting plate disclosed in Patent Document 2 is adopted in the sheet feeder provided with the sheet upper surface detecting means shown in Patent Document 1, the feeding roller comes into contact even if the sheet is aligned with the movable side restricting plate. Therefore, the sheets are fed out of alignment and cause poor feeding. That is, when the sheet is fed, the upper surface of the sheet is moved to the delivery position, so that the upper surface position of the sheet must be detected by the sheet upper surface detection means. Therefore, the feeding roller is in contact with the upper surface of the sheet, and even if an attempt is made to align the upper sheet with the movable side regulating plate, the feeding roller becomes a load, causing a problem that the sheet does not move or the sheet is bent. . As a result, the sheet is skewed to cause a paper feed failure.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a sheet feeding device that can reliably align sheets on a stacking tray by a movable regulating plate and prevent sheet feeding defects. And

  In order to achieve the above object, the present invention presses the stacking tray for stacking sheets, a feed roller for feeding the sheet in contact with the sheets on the stacking tray, and the widthwise end of the sheet on the stacking tray. A first moving means for moving the stacking tray in order to move the uppermost surface of the stacked sheets to a sending position for sending the sheets by the sending roller. And a second moving means for moving the feeding roller from the abutting position at which the feeding roller comes into contact with the uppermost surface of the sheet to a retracted position away from the upper surface of the sheet, and raising the stacking tray to move the uppermost surface of the sheet to the feeding position. And a control means for controlling the first and second moving means so as to move the delivery roller from the contact position to the retracted position.

  Since the feeding roller is moved away from the uppermost surface of the sheet after the uppermost surface of the sheet reaches the feeding position, the movable upper-limit sheet can be moved by the movable restricting means, and the sheets can be aligned reliably. Accordingly, it is possible to prevent conveyance failure due to sheet skew or the like.

1 is a diagram illustrating an overall configuration of an image forming system including a sheet feeding device according to the present invention. 1 is a cross-sectional view illustrating a sheet feeding device according to the present invention. It is a perspective view which shows the storage of the sheet feeding apparatus which concerns on this invention. It is a top view of the storage of the sheet feeding apparatus according to the present invention. It is a figure which shows the movement control means for aligning a sheet | seat within a storage, (a) is principal part sectional drawing of a movement control means, (b) is an effect | action figure of a movement control means. FIG. 6 is a schematic diagram illustrating a retraction mechanism and a sheet upper surface detection mechanism for moving a feeding roller of the sheet feeding device according to the present invention. 3 is a control block showing a control system of the sheet feeding apparatus according to the present invention. FIG. 6 is a flowchart illustrating a sheet feeding preparation operation of the sheet feeding apparatus according to the present invention. FIG. 6 is a flowchart illustrating a sheet feeding operation of the sheet feeding apparatus according to the present invention. FIG. 6 is a state diagram illustrating a state of a delivery roller in a paper feeding preparation operation.

  FIG. 1 is a diagram illustrating an overall configuration of an image forming system including a sheet feeding device. As shown in the figure, an image forming system includes an image forming apparatus 1 that prints an image on a sheet, an original reading apparatus 2 that reads an original, an original feeding apparatus 3 that conveys a sheet to a reading unit of the original reading apparatus 2, and an image forming system. A sheet feeding device 4 that supplies sheets to the apparatus 1 and a sheet stacking device 5 that is connected to a sheet discharge port of the image forming apparatus 1 and stacks sheets discharged from the image forming apparatus 1 are configured.

  The image forming apparatus 1 includes two paper feed cassettes 6a and 6b that can store about 100 sheets. Then, the sheet is taken out from any one of the two paper feeding cassettes 6 a and 6 b and the sheet feeding device 4, the image data transferred from the document reading device 2 is printed on the taken-out sheet, and the sheet is discharged by the paper discharge roller pair 10. It is discharged to the accumulation device 5.

  The image forming apparatus 1 performs electrostatic printing, and includes a beam projector 12 that forms an electrostatic latent image on a photosensitive drum 11, a developing device 13 that attaches toner ink to the electrostatic latent image, and a transfer charger 14. ing. Then, the image ink formed on the photosensitive drum 11 is transferred onto the sheet by the transfer charger 14, and the image on the sheet is heated and fixed by the fixing roller 15 disposed downstream thereof, and conveyed to the sheet stacking device 5. It is the composition to do.

  The sheet feeding device 4 includes a storage unit (storage) 30 capable of storing 3000 sheets more than the sheet feeding cassettes 6a and 6b, and in accordance with a sheet feeding command from the image forming apparatus 1, the sheets are fed one by one. The image is supplied to the image forming apparatus 1.

  In the document reading device 2, a first platen 16 and a second platen 17 formed of transparent glass are juxtaposed in the horizontal direction at the top of the device. The first platen 16 is used for reading a document set manually, and is formed to have a maximum size of a usable document. The second platen 17 is used for reading a document that moves at a predetermined speed.

  Inside the image reading apparatus 2, there are provided first and second reading carriages 18 and 19, and photoelectric conversion means having a condenser lens 20 and a photoelectric conversion element 21 (CCD). Although not shown, the first and second reading carriages 18 and 19 are driven by a carriage motor to reciprocate below the first platen 16 in the sub-scanning direction. The first reading carriage 18 is provided with a lamp that irradiates light toward the original and a mirror that reflects the light reflected from the original, and the second reading carriage 19 includes the first reading carriage 18. Two mirrors for guiding light from the mirror to the condenser lens 20 and the photoelectric conversion element 21 are provided. Then, the first and second reading carriages 18 and 19 move to irradiate the original set on the first platen 16 with light, and the photoelectric conversion element 21 performs photoelectric conversion on the reflected light from the original. Read. The original image data read by the photoelectric conversion element 21 is transmitted as an image signal to the beam projector 12 of the image forming apparatus 1.

  The document feeder 3 discharges the document set on the sheet feed tray 22 through the second platen 17 by the sheet transport mechanism 24 and discharges it to the sheet discharge tray 23. When reading a document passing over the second platen 17 with the document feeder 3, the first and second reading carriages 18 and 19 are stopped under the second platen 17 to read the moving document.

FIG. 2 is a cross-sectional view showing the sheet feeding device 4. 3 is a perspective view showing the storage 30 provided in the sheet feeding device 4 in FIG. 3, and FIG. 4 is a top view of the storage 30. Further, FIG. 5 is a cross-sectional view and an operation view of the main part showing the movable restricting means for aligning the sheets in the storage 30.
As shown in FIGS. 2 and 3, the sheet feeding device 4 includes a storage 30 that is pulled out for setting sheets, and a paper feeding mechanism 31 that feeds the sheets in the storage 30. A large amount of sheets are collected in the storage 30, and a stacking tray 32 that moves up and down in the vertical direction, regulation plates 33 and 34 that regulate the position in the width direction of the sheet, and a rear end regulation plate that regulates the rear end position of the sheet. 35 and an elevating mechanism (first moving means) for elevating and lowering the stacking tray 32. The sheet feeding device 4 is provided with a sheet upper surface detection mechanism 38 as a sheet upper surface detection unit that detects the position of the uppermost surface of the stacked sheets, which will be described later.

  As shown in FIGS. 3 and 4, the regulation plates 33 and 34 of the storage case 30 are provided on both the front side and the rear side in the drawer direction of the storage case, that is, on both sides in the sheet width direction perpendicular to the sheet feeding direction. A pair of restricting plates 33 and 34 are provided so as to face each other. The pair of restricting plates includes a first restricting plate 33 that restricts one end side of the sheet and a second restricting plate 34 that restricts the other end side. The first restricting plate 33 is a side portion 36 a of the frame 36 of the storage 30. The second restricting plate 33 is attached to the upper surface of the side portion 36b facing the wall portion 36a with a fixing member. Although not shown, attachment holes (screw holes) corresponding to the size of the sheet are formed on the upper surfaces of the side portions 30a and 30b, and the first and second regulating plates 33 and 34 are accommodated in the storage 30. The first and second restricting plates 33 and 34 can be positioned at positions corresponding to the sheet size by attaching them to the screw holes corresponding to the size of the sheet to be processed.

  FIGS. 5A and 5B are a cross-sectional view and an operation view of the main part of the movable restricting means for aligning the sheets in the storage 30. FIG. A notch 46 is formed in the upper part of the first restricting plate 33 on the downstream side in the sheet feeding direction. The notch 46 is formed from a leaf spring 50 and a pressing member 51 as shown in FIG. A movable restricting mechanism 49 is provided as a movable restricting means. The leaf spring 50 of the movable restriction mechanism 49 is attached to the back surface different from the restriction surface 33b of the first restriction plate 33 by caulking. The pressing member 51 is formed with press-fit pins 51 a and 51 b, and the press-fit pins 51 a and 51 b are press-fitted into fitting holes 50 a and 50 b provided on the distal end side of the leaf spring 50. Thereby, the pressing member 51 is attached to the leaf spring 50. Further, the pressing member 51 is provided so as to protrude from the restricting surface 33b of the first restricting plate 33, and a pressing surface 51c is formed at a portion protruding to the second restricting plate 34 side.

  As shown in FIG. 5B, when the pressing surface 51 c is pressed by the end portion of the stacked sheets, the leaf spring 50 is bent and an elastic force is generated in the leaf spring 50. The pressing surface 51 c of the pressing member 51 acts so as to press the end portion of the sheet against the regulating surface 34 a of the other regulating plate 34 by the elastic force of the leaf spring 50. As a result, the end of the sheet in the width direction is aligned along the restriction surface of the second restriction plate 34.

  In the present embodiment, the pressing member 51 is formed of an aluminum material that is less likely to be worn, scraped, wrinkled, or the like due to the end of the sheet that is fed out. In the embodiment, the pressing member is made of an aluminum material, but any material that does not easily wear may be used.

  The trailing edge regulating member is movably provided in a slide groove formed at the bottom of the frame body 36 and moves according to the sheet size to regulate the trailing edge of the sheets stacked on the stacking tray 32.

  The loading toilet 32 is a plate-like plate on which sheets stored in the storage 30 are stacked. Both side portions 36a and 36b of the frame body 36 are respectively formed with long openings in the vertical direction, and the both sides of the stacking tray 32 in the sheet width direction are laterally opened from the openings of the both side portions 36a and 36b of the frame body 36. Support portions 4a and 4b provided so as to protrude are provided. The support portions 4a and 4b are supported by an elevating mechanism provided on the outer surface of the side portions 36a and 36b of the frame body 36, and the stacked sheets are moved up and down in a substantially horizontal state by driving the elevating mechanism.

  As shown in FIGS. 2, 3, and 4, the elevating mechanism includes four wires 55 fixed to four support portions 4 a, 4 b, 4 c, and 4 d provided on both sides of the stacking tray 32, and 4 A plurality of pulleys 52 on which the wires 55 are respectively hung, a plurality of winding pulleys 53 that are attached to the same shaft and wind up the four wires 55, and a plurality of pulleys for driving the four winding pulleys 53 A drive gear 54 and a lifting motor M3 that drives the take-up pulley 53 via the drive gear 54 are included. Then, when the elevating motor M3 is driven to rotate in the forward direction, the four take-up pulleys 53 are rotated to wind up the wires 55, respectively. As a result, the four support portions 4a and 4b of the stacking tray 32 are pulled up simultaneously, and the stacking tray 32 is raised while maintaining a substantially horizontal state. On the other hand, when the elevating motor M3 is driven in reverse, the take-up pulley 53 is rotationally driven in the opposite direction, and the stacking tray is lowered in a horizontal state by its own weight.

  The paper feed mechanism 31 is in contact with the uppermost surface of the stacked sheets and feeds out the sheets, separation means for separating and feeding the fed sheets into one sheet, and the separation means into one sheet. A conveying roller pair 43 that conveys the separated sheet to the image forming apparatus 1. The separation unit includes a paper feed roller 41 and a separation roller 42 that presses against the paper feed roller 41 and prevents the feeding of one or more sheets.

  FIG. 6 is a schematic diagram showing a retracting mechanism for moving the feeding roller 40 and a sheet upper surface detecting mechanism described later. As shown in FIG. 6, the delivery roller 40 is supported by a placket 44 that can swing in the vertical direction. The delivery roller 40 is pressed by its own weight on the uppermost surface stacked on the stacking tray 32, and the delivery roller 40 can be retracted from the upper surface of the sheet by a retracting mechanism (second moving means). The retraction mechanism includes a solenoid SOL, a first link member 60 having one end connected to the solenoid SOL and the other end fixed to the rotating shaft 62, one end fixed to the rotating shaft 62, and the other end supporting the delivery roller 40. A second link member 61 connected to the bracket 44 to be operated. The retracting mechanism pulls the plunger of the solenoid SOL by energizing the solenoid SOL. When the plunger is pulled, the first link member rotates counterclockwise in the drawing. As a result, the rotation shaft rotates and the second link member 61 attached to the rotation shaft rotates in the same direction as the second link member. The bracket 44 is pulled up by the rotation of the second link member and is rotated about the shaft of the paper feed roller 41, and the feeding roller 40 is separated from the uppermost surface of the sheet from the contact position where the feeding roller 40 is in contact with the uppermost surface of the sheet. Move to the retracted position.

  The paper feed roller 41 is drivingly connected to the paper feed motor M1 by a plurality of gears and timing belts, and rotates by the paper feed motor M1 to feed a sheet. The bracket 44 of the feed roller 40 is rotatably supported on the shaft of the paper feed roller 41, and the shaft of the paper feed roller 41 is drivingly connected to the shaft of the feed roller 40 via a plurality of gears. The drive of the motor M1 is transmitted to the delivery roller 40 via the shaft of the paper feed roller 41.

  The separation roller 42 is provided with a torque limiter (not shown) on its rotating shaft. As a result, when two or more sheets are overlapped and nipped at the pressure contact portion between the sheet feeding roller 41 and the separation roller 42, the sheet is stopped and the second and subsequent sheets are prevented from being fed. That is, when a plurality of sheets overlap and enter the nip portion between the paper feed roller 41 and the separation roller 42, the driving force of the paper feed roller 41 is transmitted to the uppermost sheet, and between the second and subsequent sheets. Slip occurs, and the first sheet and the second and subsequent sheets are separated. Of course, a separation pad may be used instead of the separation roller 41.

  The conveyance roller pair 43 includes a drive roller that is drivingly connected to the conveyance motor M2, and a driven roller that is driven to rotate by the drive roller. Then, the sheet is fed from the sheet feeding device 4 to the image forming apparatus 1 by the rotation of the driving roller of the pair of conveying rollers 43 by the driving of the conveying motor M2.

  As shown in FIG. 6, the sheet upper surface detection mechanism 38 detects that the uppermost surface of the stacked sheets on the stacking tray 32 has been raised to the delivery position. The sheet upper surface detection mechanism 38 includes a photo sensor SE fixed to the upper part of the sheet feeding device 1 and a detection flag SF provided on the bracket 44 of the feed roller 40. The photo sensor SE includes a light emitting element and a light receiving element, and the detection flag SF blocks the light path between the light emitting element and the light receiving element of the photo sensor SE, thereby detecting that the uppermost surface of the sheet is at the sending position.

  Specifically, when the stacking tray 32 rises, the uppermost surface of the sheets stacked on the stacking tray 32 comes into contact with the peripheral surface of the sending roller 40 suspended by its own weight, and pushes up the sending roller 40. When the feed roller 40 is pushed up, the bracket 44 also moves upward. When the detection flag SF provided on the bracket 44 blocks the optical path of the photosensor SE, the output of the photosensor SE changes from “L” (OFF) to “H” (ON). Thereby, it is detected that the uppermost surface of the sheet has reached the delivery position. Further, when the uppermost surface of the sheet is lowered by the sheet feeding, the feeding roller 40 follows the uppermost surface of the sheet and falls. As a result, the bracket 44 also moves downward. When the detection flag SF provided on the bracket 44 releases all the optical path of the photosensor SE, the output of the photosensor SE changes from “H” (ON) to “L” (OFF). Thus, it is detected that the uppermost surface of the sheet has reached the lower limit of the position where the sheet can be sent out.

  With the configuration described above, when stacking sheets in the storage case 30, the stacking tray 32 is raised after the sheets are placed in the storage case 30, and the sheet upper surface detection mechanism indicates that the uppermost surface of the sheet has reached the delivery position. When 38 is detected, control is performed to stop the raising of the stacking tray 32. When a sheet is fed, the uppermost surface of the sheet is gradually lowered each time the sheet is fed, and the position of the feeding roller 40 is lowered accordingly. When a predetermined number of sheets are sent out, the stacking tray 32 is raised when the sheet upper surface detection mechanism 38 detects that the position of the feeding roller 40, that is, the position of the uppermost surface of the sheet has reached the lower limit position where the sheet can be fed. Let Thereafter, when the sheet upper surface detection mechanism 38 detects that the uppermost surface of the sheet has reached the delivery position, the stacking tray 32 is controlled to stop rising.

  FIG. 7 is a control block diagram showing the control system. In addition to the above-described photosensor SE, the sheet feeding device 4 includes an empty sensor S1 that detects that a document is placed on the stacking tray 32, and conveyance between the sheet feeding roller 41 and the conveyance roller pair 43. A sheet detection sensor S2 that is disposed on the path and detects a fed sheet and a storage set sensor SA that detects that the storage 30 is locked at a predetermined position are provided. As shown in the control block diagram of FIG. 7, each sensor SE, S1, S2, SA is connected to a control unit (control means) 100 having a CPU, a ROM, and a RAM. The motors M1, M2, M3 and solenoids are driven and controlled based on the various information and detection signals from the sensors.

  FIG. 8 is a flowchart illustrating a sheet feeding preparation operation at the time of sheet setting, and FIG. 9 is a flowchart illustrating a sheet feeding operation of the sheet feeding apparatus. FIG. 10 is a state diagram showing the state of the delivery roller in the paper feed preparation operation. The paper feed preparation operation will be described with reference to FIG. In this sheet feeding preparation operation, the storage case 30 is pulled out, a sheet is set, and the storage case 30 is pushed into a predetermined position so that the sheet feeding operation can be started.

  First, when the storage 30 is pushed into a predetermined position and the storage set sensor SA detects that the storage is locked, it is confirmed whether or not the photo sensor SE is OFF (ST01-ST02). If the photo sensor is OFF, it is determined that the uppermost surface of the sheet is not at the delivery position, and the elevating motor M3 is driven to rotate forward (ST03). As a result, as shown in FIG. 10A, the stacking tray 32 rises, the uppermost surface of the sheet on the stacking tray 32 rises, and the sheet pushes up the feeding roller 40. Then, as shown in FIG. 10B, when the photosensor SE is turned on, that is, when it is detected that the uppermost surface of the sheet has reached the feeding position, the lifting motor M3 is stopped (ST04-ST05).

  When the uppermost surface of the sheet reaches the delivery position, the solenoid SOL is turned on (energized) (ST06). As a result, as shown in FIG. 10C, the bracket 44 is pulled up, and the feeding roller 40 supported by the bracket 44 moves from the contact position where it contacts the uppermost surface of the sheet to the retracted position separated from the uppermost surface of the sheet. To do.

  That is, here, when the photo sensor SE is turned on, the feeding roller 40 is separated from the uppermost surface of the sheet. When the feeding roller 40 is separated from the uppermost surface of the sheet, the sheet pressed by the feeding roller 40 is released from the pressed state and becomes free, and the pressing surface of the pressing member 51 is pressed by the elastic action of the leaf spring 50 of the movable restricting mechanism 49. 51c pushes the end of the sheet toward the opposing regulating plate 34. The opposite end of the sheet pressed by the pressing surface 51c of the pressing member 51 is pressed against the regulating surface 34a of the regulating plate 34, and the width direction of the sheet is aligned (see FIG. 5B).

  If a predetermined time t1 has elapsed after the feeding roller 40 has been separated from the uppermost surface of the sheet, the solenoid SOL is turned off (not energized) (ST07-ST08). As a result, the feeding roller 40 comes into contact with the uppermost surface of the sheet by its own weight. Then, the apparatus waits in this state, and when a paper feed command is received from the image forming apparatus 1, a paper feed operation is executed.

Next, the paper feeding operation will be described with reference to FIG. 9. The paper feeding operation starts when a paper feeding command is received from the image forming apparatus 1. A paper feed command is transmitted from the image forming apparatus 1 for each sheet, and a paper feeding operation is executed for each sheet.
In the paper feeding operation, first, the photo sensor SE detects whether or not the uppermost surface of the sheet is at the delivery position (ST10). If the uppermost surface of the sheet is not at the delivery position as a result of detection by the photosensor SE, the elevating motor M3 is driven to rotate forward and is raised until the photosensor SE is turned on (ST11-ST12). When the photosensor SE is turned on, the lift motor M3 is stopped (ST13). As a result, the uppermost surface of the sheet is positioned at the delivery position.

  When the uppermost surface of the sheet reaches the delivery position, the solenoid SOL is turned on and operated, and the bracket 44 is pulled up (ST14). As a result, the feeding roller 40 is separated from the uppermost surface of the sheet, and the sheet pressed by the feeding roller 40 is released. Then, the released sheet is pushed toward the opposing regulating plate 34 by the pressing surface 51c of the pressing member 51, and is brought into contact with and aligned with the regulating surface 34a of the regulating plate 34 (see FIG. 5B).

  If a predetermined time t2 has elapsed after the feeding roller 40 has been separated from the uppermost surface of the sheet, the solenoid SOL is turned off (not energized) (ST15-ST16). As a result, the feeding roller 40 comes into contact with the uppermost surface of the sheet by its own weight.

  The operations from Step 10 to Step 16 (ST10 to ST16) are the same as the operations from Step 01 to Step 08 (ST01 to ST08) in the above-described paper feed preparation operation.

  Then, after the solenoid SOL is turned off and the feeding roller 40 is brought into contact with the uppermost surface of the sheet, the sheet feeding motor M1 and the conveying motor M2 are driven (ST17). As a result, the feed roller 40, the paper feed roller 41, and the transport roller 43 rotate, and the uppermost sheet on the stacking tray 32 is sent out by the feed roller 40.

  After the sheet is fed by the feeding roller 40, the sheet detection sensor S2 is turned on, that is, when a predetermined time t3 has elapsed since the sheet detection sensor S2 detected the leading edge of the sheet, the sheet feeding motor M1 is stopped, and the feeding roller 40 Then, the paper feed roller 41 is stopped (ST18-ST20). At this time, the leading end side of the sheet is nipped by the conveyance roller pair 43, and the sheet is conveyed while being pulled out from the nip portion between the paper feed roller 41 and the separation roller 42 by the conveyance roller pair 43. The predetermined time t2 is the time required from the time when the leading edge of the sheet is detected by the sheet detection sensor S2 until the leading edge of the sheet is nipped by the conveying roller pair 43.

  Thereafter, after the sheet detection sensor S2 is turned off, that is, after the trailing edge of the sheet is detected by the sheet detection sensor S2, the transport motor M2 is stopped when a predetermined time t4 has elapsed, and the paper feeding operation is terminated (ST21-ST23). ). Note that the sheet is already nipped by the receiving roller pair 26 of the image forming apparatus 1 when the predetermined time t3 has elapsed, and is conveyed into the image forming apparatus 1 without any trouble.

  According to the above-described embodiment, the feeding roller 40 is separated from the uppermost surface of the sheet after the uppermost surface of the sheet reaches the feeding position, and then the feeding of the sheet is started. The sheet at the upper part of the stack can be moved on the surface 51c, and the sheets can be reliably aligned. Accordingly, it is possible to prevent conveyance failure due to sheet skew or the like.

  Further, each time the sheet is raised, the feeding roller 40 is separated from the uppermost surface of the sheet so as to align the sheets. Therefore, even when a large number of sheets are continuously fed, the uppermost sheet is always maintained. Be aligned.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 4 Sheet feeding apparatus 30 Storage 31 Paper feeding mechanism 32 Stacking tray 33 1st regulation board 34 2nd regulation board 35 Rear end regulation board 38 Sheet upper surface detection mechanism 40 Sending roller 41 Paper feeding roller 42 Separating roller 44 Bracket 49 Movable restriction mechanism 50 Leaf spring 51 Press member M1 Paper feed motor M3 Lift motor SOL Solenoid SE Photo sensor SF Detection flag

Claims (5)

A stacking tray for stacking sheets, a feed roller that contacts the sheets on the stacking tray and feeds the sheets, and a movable restricting unit that presses and regulates an end of the sheet on the stacking tray in the width direction. In the paper feeder provided,
First moving means for moving the stacking tray to move the uppermost surface of the stacked sheets to a sending position where the sheets are sent out by the sending roller;
Second moving means for moving the feeding roller from a contact position that contacts the uppermost surface of the sheet to a retracted position that is separated from the upper surface of the sheet;
Control means for controlling the first and second moving means so as to move the sending roller from the contact position to the retracted position after raising the stacking tray and moving the uppermost surface of the sheet to the sending position; And a sheet feeding device.   The movable restricting means is a restricting member that comes into contact with an end portion of the upper portion of the stacked sheets in a state where the uppermost surface of the stacked sheets is at the delivery position, and biases the restricting member toward the end portion of the sheet. The sheet feeding device according to claim 1, further comprising an elastic member.   Sheet upper surface detection means for detecting that the uppermost surface of the stacked sheets has reached the delivery position, and the control means operates the second moving means based on the detection result of the sheet upper surface detection means. The sheet feeding device according to claim 1, wherein the sheet feeding device is a sheet feeding device.   4. The sheet feeding according to claim 3, wherein the sheet upper surface detection unit includes a detection flag provided in a support unit that movably supports the feeding roller, and a photosensor that detects the detection flag. 5. apparatus. The movable restricting means is disposed on one end side in the sheet width direction orthogonal to the sheet feeding direction, fixedly disposed on the other end side in the sheet width direction, and fixed restricting means for restricting the other end portion of the sheet. The sheet feeding device according to claim 1, further comprising: a sheet feeding device according to claim 1.

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