JP2012140206A - Paper feeder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a paper feeder capable of consecutively conveying an original in a state the a paper feeding interval is shortened to the minimum by surely making the original delivered consecutively stand by at a paper feeding position without deforming the original.SOLUTION: The paper feeder includes: a roller (rotating body) 33 that is arranged at an upstream side of a press-contact position where a paper feeding roller 24 and a separation means 25 are brought into press-contact with each other, rotates in contact with a following sheet delivered in a state that it is superposed on a preceding sheet, and stops when the movement of the following sheet is prevented by the separation means 25; an encoder (rotation detection means) 34 that detects the rotation/stop of the roller 33; and a controller (control means) CONT that stops a delivering roller 23 based on a result obtained by detecting the stop of the roller 33 by the encoder 34.

Description

  The present invention relates to a sheet feeding device that continuously feeds sheets placed on a sheet feeding tray.

  2. Description of the Related Art Conventionally, in a sheet feeding device that feeds a sheet to a predetermined processing position such as a sheet feeding position or a reading position, a sheet feeding tray for placing a plurality of sheets, and a sheet placed on the sheet feeding tray. A plurality of sensors for detecting various rollers and sheet positions that are brought into contact with the sheet surface being fed and fed into a conveyance path provided with a reading unit and the like are provided.

  The rollers provided in the sheet feeding device include a feeding roller that feeds out a sheet placed on a sheet feeding tray and a sheet feeding roller that feeds the sheet fed by the feeding roller toward a conveyance path. . On the downstream side of the feeding roller, a separation member for separating the sheets into one sheet is provided so that sheets fed into the conveyance path by the sheet feeding roller do not overlap.

  Further, a sheet detection sensor for detecting the position of the sheet is provided on the downstream side of the separation member, and when the trailing edge of the preceding sheet previously sent to the conveyance path is detected by the sheet detection sensor, the succeeding subsequent There is a case where control such as start of sheet feeding is performed.

  In the sheet feeding device, it is desirable to shorten the sheet feeding interval as much as possible in order to improve the productivity of sheet processing. For this reason, in the conventional sheet feeding apparatus, the separation member and the sheet detection sensor are arranged with a minimum interval that does not hinder sheet conveyance.

  However, in the conventional general sheet feeding device, the succeeding sheet that follows the preceding sheet does not necessarily reach the separating member and is separated, but the sheet depends on the type of sheet to be used, the paper quality, or the usage environment. Variations occur in the transfer position. That is, when the trailing edge of the preceding sheet is detected by the sheet detection sensor and the succeeding sheet is fed out, the position of the leading edge of the succeeding sheet is not constant and may be indefinite. For this reason, the sheet feeding interval varies, which causes a reduction in sheet processing productivity.

  Several paper feeding apparatuses having a paper feeding mechanism for improving the above problems have been proposed. For example, in the invention disclosed in Patent Document 1, even after the preceding sheet passes through the feeding roller position, the succeeding sheet is fed out while maintaining the rotation of the feeding roller, and the succeeding sheet hits the preceding sheet feeding roller. Thus, the feeding roller is stopped after detecting the occurrence of bending deformation (loop). After that, when the trailing edge of the preceding sheet is detected by the sheet detection sensor provided on the downstream side of the sheet feeding roller, the feeding roller is rotated again, and the succeeding sheet having a loop at the leading edge is controlled to be fed. The As a result, when the feeding of the succeeding sheet is started, the leading edge of the succeeding sheet always reaches the feeding roller, so that the interval between continuously fed sheets is always constant. Can keep.

  Note that the invention disclosed in Patent Document 2 is the same as Patent Document 1 in that a loop is generated at the leading edge of the succeeding sheet in order to keep the sheet feeding interval constant.

JP 2001-72268 A Japanese Patent Laid-Open No. 2008-169026

  However, in the inventions of Patent Documents 1 and 2 described above, it is not detected that the leading edge of the succeeding sheet has reached the position of the sheet feeding roller unless a certain loop is formed. When such a loop is formed, the sheet is damaged. In particular, when the paper quality of the sheet is thin, there is a case where the leading edge is wrinkled before the loop is formed and cannot be restored or the sensor for detecting the loop does not react. On the other hand, when the paper quality of the sheet is thick, a loop cannot be formed, and the leading edge of the sheet may enter between the separation member and the paper feed roller. In such a case, the succeeding sheet is caught by the preceding sheet to cause double feeding, or the feeding roller may slide on the succeeding sheet, and the sheet surface may be soiled by slip marks.

  Further, since the loop has variations in shape and size depending on the type of sheet, the feeding speed, and the like, there is a problem that the arrangement position and sensitivity of the sensor for detecting the loop must be adjusted appropriately. .

  Accordingly, the present invention provides a paper feeding device that can continuously feed a sheet that is continuously fed out at a paper feeding position without deforming the sheet, and can continuously carry the paper with a minimum paper feeding interval. The purpose is to provide.

  In order to solve the above problems, a sheet feeding device according to the present invention includes a sheet feeding tray on which a plurality of sheets are placed, and a feeding roller that feeds out the sheet in contact with the upper surface of the sheet placed on the sheet feeding tray. A sheet feeding roller that conveys the sheet fed by the feeding roller along the conveying path, and a movement of a succeeding sheet following the preceding sheet that is pressed against the sheet feeding roller and fed by the sheet feeding roller And a separating unit that separates the succeeding sheet from the preceding sheet and is disposed upstream of the pressure contact position between the sheet feeding roller and the separating unit and overlaps the preceding sheet A rotating body that rotates in contact with a succeeding sheet that is fed out in a state and stops when the separating means prevents movement of the succeeding sheet; and a rotation detecting means that detects rotation / stop of the rotating body; , Serial characterized by comprising a control means for stopping the feeding roller based on the stopping of the rotating body to detecting said rotation detecting means.

  According to the sheet feeding device of the present invention, when the sheet is fed from the sheet feeding tray by the feeding roller, the subsequent sheet that is fed under the preceding upper sheet is prevented from moving by the separating unit, By stopping the rotation of the rotating body, the feeding position of the subsequent sheet can be known. Further, by controlling so that the rotation of the feeding roller is stopped at the same time when the rotating body is stopped, the subsequent sheet is not excessively fed out. Accordingly, it is possible to reliably wait at the sheet feeding position without causing the subsequent sheet to bend and deform.

1 is a cross-sectional view illustrating an overall configuration of a sheet conveying apparatus including a sheet feeding device according to the present invention. It is a side view which shows the structure of the said paper feeding apparatus. It is explanatory drawing which shows the drive structure of the said paper feeding apparatus. It is a flowchart which shows the flow of control of the said sheet feeding apparatus. FIG. 10 is an explanatory diagram illustrating a first paper feeding operation pattern. FIG. 10 is an explanatory diagram illustrating a second paper feeding operation pattern.

  Hereinafter, an embodiment of a paper feeding device according to the present invention will be described in detail with reference to the drawings. FIG. 1 shows an overall configuration of a sheet conveying apparatus 1 provided with a sheet feeding device 20 of the present invention. The sheet conveying apparatus 1 includes a main body unit 2 having an image reading unit 4 and a conveying / reading unit 3 attached to the upper side of the main body unit 2 so as to be openable and closable.

  The image reading unit 4 reads a sheet passing through the upper surface of the first contact glass 6 with the optical unit 5 fixed. Further, a second contact glass 7 having a plane space for placing a sheet is provided on the upper surface of the main unit 2, and the image reading unit 4 is provided for the sheet set on the contact glass 7. It can be read by moving the optical unit 5.

  The image reading unit 4 includes a light source 10 such as a lamp, a plurality of mirrors 11, a lens 16, a photoelectric conversion element 17 such as a CCD, and the like. The sheet that is conveyed or placed is irradiated with light emitted from the light source 10 via the first contact glass 6 or the second contact glass 7. Then, after the light irradiated and reflected on the sheet surface is reflected several times by the plurality of mirrors 11, the photoelectric conversion element 17 performs photoelectric conversion via the lens 16 to read the sheet image.

  Next, the configuration of the transport reading unit 3 will be described. As shown in FIG. 1, the transport reading unit 3 includes a sheet feeding tray 21 on which a plurality of sheets can be placed, and a regulation plate 22 that regulates sheet width direction end portions of the plurality of placed sheets. And a paper discharge tray 8 for storing the sheet that has been read.

  Further, the transport reading unit 3 includes a paper feed path 12 that feeds one sheet at a time from a plurality of sheets stacked on the paper feed tray 21, and a first contact glass 6 from the paper feed path 12. A sheet conveyance path is provided that includes a reading path 13 extending via the sheet and a discharge path 14 extending from the reading path 13 to the discharge tray 8.

  A sheet feeding device 20 according to the present invention is provided on the downstream side of the regulating plate 22. The sheet feeding device 20 includes a feeding roller 23 for feeding a sheet from the sheet feeding tray 21, a sheet feeding roller 24 for feeding the fed sheet, and one sheet in contact with the sheet feeding roller 24. Separating means 25 for separating each one. In addition, the separating means 25 is provided with a separating plate 38 for separating the sheet fed by the feeding roller 23.

  As shown in FIG. 2, the separation means 25 is supported by a separation frame 30 attached and fixed to the conveyance reading unit 3 and a spring member 32 in the separation frame 30. And a separation plate 31 arranged so as to be elastically pressed.

  The separation frame 30 is provided with a rotating body (roller) 33 near the upstream side of the separation plate 31. The roller 33 is attached to a roller rotation shaft 36 protruding into the separation frame 30 so as not to rotate. In the present embodiment, a pair (33a, 33b) of the rollers 33 are arranged so as to be in contact with both ends along the rotation direction of the paper feed roller 24. A roller rotating shaft 36 that supports one roller 33 a is connected to a rotating plate 34 a via a rotating gear 39 attached to the separation frame 30.

  As shown in FIG. 3, the rotation plate 34a is provided with a large number of detection holes in a radial pattern in the circumferential direction, and a transmission type photo interrupter 35 comprising the rotation plate 34a, a light emitting element, and a light receiving element. Constitutes a rotation detecting means (encoder) 34. That is, the rotating plate 34a rotates integrally with the roller 33, and the photo interrupter 35 detects a detection hole of the rotating plate 34a and outputs a pulse signal synchronized with the rotation of the rotating plate 34a. Then, the control means (control unit) CONT determines that the roller 33 is rotating when the pulse signal of the photo interrupter 35 is generated, and the roller 33 stops when the pulse signal is not generated. Judge that

  Next, the drive configuration of the paper feeding device 20 will be described with reference to FIG. In the paper feeding device 20, the feeding roller 23, the paper feeding roller 24, and the registration roller 26 are rotationally driven by a single system of rotational driving source (paper feeding motor) MT. The feeding roller 23, the paper feeding roller 24, and the registration roller 26 are provided with independent clutches CL1, CL2, and CL3, respectively, and each clutch is turned on by detection signals from the encoder 34, the separation sensor 41, and the registration sensor 42. To stop the rotation.

  The sheet feeding motor MT is activated when a sheet is placed on the sheet feeding tray 21 and the leading edge of the sheet is detected by an empty sensor (not shown) provided on the regulating plate 22, and this activation activates the feeding rollers 23, The sheet feeding roller 24 and the registration roller 26 rotate in the sheet feeding direction (from right to left in the figure). The clutch CL1 is turned off when the encoder 34 detects that the rotation of the roller 33 has stopped, and stops the rotation of the feeding roller 23. The clutch CL1 is kept off until the preceding sheet (preceding sheet) P1 passes the separation sensor 41, and is turned on (ON) when the trailing edge of the preceding sheet P1 is detected. Starts rotating. The clutches CL2 and CL3 are switched to an on / off state in accordance with the sheet conveyance state.

  As shown in FIG. 1, a reading path 13 passing through the first contact glass 6 and a paper discharge path 14 connected to the reading path 13 are provided on the downstream side of the registration roller 26. The reading path 13 is provided with a first read roller 27 and a second read roller 28, and performs a rotation stop operation in accordance with the detection state of the read sensor 43 to read and convey the sheet. Further, the paper discharge path 14 is provided with a paper discharge roller 29 for feeding the sheet to the paper discharge tray 8, and the rotation stop operation is performed according to the detection state of the paper discharge sensor 44, and the sheet that has been read is discharged to the paper discharge tray. The paper is conveyed toward 8. The first lead roller 27, the second lead roller 28, and the paper discharge roller 29 are driven and controlled by a drive motor and a clutch (not shown) separate from the paper feed motor MT that drives the paper feed device 20. Is done.

  Next, the operation of two patterns with different sheet feeding states (FIGS. 5 and 6) are shown in the drive configuration diagram of FIG. 3, the feeding operation flow of FIG. 4A, and the feeding stop operation flow of FIG. 4B. This will be described with reference to FIG. Here, FIG. 5 shows a first pattern in which the succeeding sheet P1 is fed toward the roller 33 so as to overlap the preceding sheet P1 when the preceding sheet P1 is at the feeding roller 23 position. is there. FIG. 6 shows the position of the roller 33 in a state in which the succeeding sheet P2 is overlapped with the rear end portion of the preceding sheet P1 without being fed to the preceding sheet P1 after the preceding sheet P1 has passed through the feeding roller 23 position. 2 shows a second pattern drawn out.

  In the first pattern, as shown in FIG. 5A, a plurality of sheets are placed on the sheet feeding tray 21, and an empty sensor (not shown) detects (ON) the leading edge of the sheet ( When ST1), the paper feed motor MT is driven (ST2). At the same time, the clutches CL1 and CL2 are drivingly connected (ON) (ST3), and the feeding roller 23 and the paper feeding roller 24 are driven to rotate simultaneously. As a result, the first sheet (preceding sheet) P <b> 1 is fed out from the uppermost part of the paper feed tray 21 by the feed roller 23, and sent out to the entrance side of the paper feed path 12 through the paper feed roller 24. At this time, as shown in FIG. 5B, the roller 33 contacts the lower surface of the preceding sheet P1, and rotates as the preceding sheet P1 moves. The subsequent second sheet (subsequent sheet) P2 and the second and subsequent sheets are fed along with the preceding sheet P1 and sequentially move downstream from the first position on the sheet feeding tray 21.

  Then, as shown in FIG. 5C, when the leading edge of the succeeding sheet P2 that has been fed reaches the roller 33 and reaches the nip position between the sheet feeding roller 24 and the separation plate 31, this position is reached. The separation plate 31 prevents the subsequent sheet P2 from moving, and the subsequent sheet P2 is separated from the preceding sheet P1 while stopped at the nip position. Thereafter, when the leading edge of the preceding sheet P1 reaches the registration sensor 42, it is detected by the registration sensor 42 that the preceding sheet P1 has entered the paper feed path 12.

  In the process of detecting the preceding sheet P1 by the registration sensor 42, a feeding stop operation (ST5) of the feeding roller 23 is executed (FIG. 4B). In this feeding stop operation, when the clutch CL1 is in the drive connection (ON) state (ST11) and the preceding sheet P1 is in the detection state by the separation sensor 41, the roller 33 stops (ST3) and the drive connection of the clutch CL1 is released. (OFF) is performed (ST14). That is, when the succeeding sheet P2 reaches the nip position between the sheet feeding roller 24 and the separation plate 31 and stops, the rotation of the roller 33 is also stopped, and when the stop of the roller 33 is detected, the feeding roller 23 stops. It will be.

  Thereafter, the sheet feeding motor MT is driven by a predetermined amount from the time when the registration sensor 42 detects the leading edge of the preceding sheet P1 (ST6). As a result, the leading edge of P1 of the preceding sheet comes into contact with the registration roller 26 and is aligned. When the leading edge alignment of the preceding sheet P1 is completed, the clutch CL2 is turned off and the clutch CL3 is turned on (ST7). As a result, the paper feed roller 24 is stopped, but the registration roller 26 is driven to rotate, so that the preceding sheet P1 is sent toward the downstream side of the paper feed path 12.

  In the process in which the preceding sheet P1 is fed by the registration roller 26, the feeding stop operation is executed again (ST8). In this case, the succeeding sheet P2 has already been moved between the sheet feeding roller 24 and the separation plate 31. Since the nip position is reached and the drive connection of the clutch CL1 is released (OFF), the subsequent processing (ST12 to ST14) is not executed.

  When the separation sensor 41 detects the trailing edge of the preceding sheet P1 (ST9), the presence or absence of the succeeding sheet P2 on the sheet feeding tray 21 is confirmed by the empty sensor (ST10). , CL2 is connected to drive (ON), and the drive connection of clutch CL3 is released (OFF). As a result, the registration roller 26 is stopped, the feeding roller 23 and the paper feeding roller 24 are rotationally driven again, and the feeding operation of the succeeding sheet P2 is started. At this time, as shown in FIG. 5D, the leading edge of the succeeding sheet P2 is at the nip position between the sheet feeding roller 24 and the separation plate 31, and the preceding sheet P1 and the succeeding sheet P2 are always at a constant spacing interval. L is held.

  In the second pattern, as shown in FIG. 6A, a plurality of sheets are placed on the sheet feed tray 21, and an empty sensor (not shown) detects (ON) the leading edge of the sheet ( When ST1), the paper feed motor MT is driven (ST2). At the same time, the clutches CL1 and CL2 are drivingly connected (ON) (ST3), and the feeding roller 23 and the paper feeding roller 24 are driven to rotate simultaneously. As a result, the preceding sheet P1 is fed by the feeding roller 23 and sent to the paper feeding path 12 by the paper feeding roller 24. At this time, as shown in FIG. 6B, the roller 33 contacts the lower surface of the preceding sheet P1, and rotates as the preceding sheet P1 moves. On the other hand, the succeeding sheet P2 and the second and subsequent sheets are hardly fed to the preceding sheet P1, or are repelled by the separating plate 31a and prevented from being fed. The nip position is not reached. Accordingly, the preceding sheet P1 proceeds on the sheet feeding path 12 as it is, and the leading edge is aligned by the registration roller 26. The roller 33 is rotating until the registration roller 26 starts to convey the preceding sheet P1 (ST5 to ST7). Therefore, the driving connection of the clutch CL1 is not released (OFF) and the feeding roller 23 rotates. continue.

  Then, as shown in FIG. 6C, when the trailing edge of the preceding sheet P1 fed by the registration roller 26 passes the feeding roller 23, the feeding roller 23 comes in contact with the upper surface of the subsequent sheet P2. As a result, the leading edge of the succeeding sheet P2 is fed out so as to continue to the trailing edge of the preceding sheet P1, and the leading edge of the succeeding sheet P2 rides on the roller 33, whereby the nip between the sheet feeding roller 24 and the separation plate 31 is reached. Reach position. The succeeding sheet P2 that has reached the nip position is stopped by the separation plate 31, and the roller 33 is also stopped rotating. That is, it is detected that the roller 33 is stopped (ST13) because the feeding of the feeding roller 23 is stopped (ST8) in the process in which the preceding sheet P1 is sent to the paper feed path 12 by the registration roller 26. As a result, the driving connection of the clutch CL3 is released, and the rotation of the feeding roller 23 is stopped.

  When the separation sensor 41 detects the trailing edge of the preceding sheet P1 (ST9), the presence or absence of the succeeding sheet P2 on the sheet feeding tray 21 is confirmed by the empty sensor (ST10). , CL2 is connected to drive (ON), and the drive connection of clutch CL3 is released (OFF). As a result, the registration roller 26 is stopped, the feeding roller 23 and the paper feeding roller 24 are rotated again, and the feeding operation of the succeeding sheet P2 is started. At this time, as shown in FIG. 6D, the leading edge of the succeeding sheet P2 is at the nip position between the sheet feed roller 24 and the separation plate 31, and the preceding sheet P1 and the succeeding sheet P2 are always at a constant spacing interval L. Will be held.

  As described above, according to the present embodiment, the feeding roller 24 is controlled so as to feed the succeeding sheet P2 to the nip position between the sheet feeding roller 24 and the separation plate 31 in a state where the succeeding sheet P1 is overlapped. The interval between sheets can be kept constant, and the productivity of sheet processing is improved. Further, the succeeding sheet P2 that is fed over the preceding sheet P1 has reached the nip position between the sheet feeding roller 24 and the separating plate 31 depending on whether or not the roller 33 disposed in the vicinity of the upstream side of the separating unit 25 is rotated. Can be easily detected. Further, when the roller 33 and the encoder 34 detect that the succeeding sheet P2 has reached the nip position between the paper feeding roller 24 and the separation plate 31, the feeding roller 23 is controlled to stop. This prevents the leading edge of the succeeding sheet from being bent or causing a loop, thereby preventing abnormal sheet feeding, damage to the sheet, contamination, and the like.

  The sheet feeding device of the present invention is not limited to the sheet conveying device shown in the above embodiment, but can be applied to a device having a mechanism for continuously feeding sheets such as a copying machine main body and a printer.

DESCRIPTION OF SYMBOLS 1 Document conveying apparatus 2 Main body unit 3 Conveyance reading unit 4 Image reading part 5 Optical part 6 1st contact glass 7 2nd contact glass 8 Paper discharge tray 10 Light source 11 Mirror 12 Paper feed path 13 Reading path 14 Paper discharge path 16 Lens 17 Photoelectric conversion element 20 Paper feed device 21 Paper feed tray 22 Restriction plate 23 Feeding roller 24 Paper feed roller 25 Separating means 26 Registration roller 27 First lead roller 28 Second lead roller 29 Paper discharge roller 30 Separation frame 31 Separation plate 32 Spring member 33 Roller (Rotating body)
34 Encoder (Rotation detection member)
34a Rotating plate 35 Photo interrupter 36 Roller rotating shaft 38 Separating plate 39 Rotating gear 41 Separation sensor 42 Registration sensor 43 Lead sensor 44 Paper discharge sensor MT Paper feed motor CONT control unit

Claims (5)

A paper feed tray on which a plurality of sheets are placed;
A feeding roller for feeding the sheet in contact with the upper surface of the sheet placed on the sheet feeding tray;
A paper feed roller that conveys the sheet fed by the feed roller along a conveyance path;
Separating means that presses against the sheet feeding roller and separates the succeeding sheet from the preceding sheet by preventing the movement of the succeeding sheet following the preceding sheet fed by the sheet feeding roller. In
Arranged on the upstream side of the pressure contact position between the paper feed roller and the separating unit, and rotates in contact with the succeeding sheet fed out in a state of being overlapped with the preceding sheet, the succeeding sheet is moved by the separating unit. A rotating body that stops by being blocked;
Rotation detecting means for detecting rotation / stop of the rotating body;
And a control unit configured to stop the feeding roller based on the fact that the rotation detecting unit detects the stop of the rotating body.   2. The sheet feeding device according to claim 1, wherein the rotating body is disposed at a position in contact with a part of the sheet feeding roller in a direction orthogonal to a sheet feeding direction with respect to the separating unit.   A separation sensor for detecting the sheet separated by the separation means is provided in the vicinity of the downstream side of the separation means, and after the trailing edge of the preceding sheet is detected by the separation sensor, the separation roller detects the subsequent sheet by the feeding roller. The sheet feeding device according to claim 1, wherein the feeding operation is started.   The sheet feeding device according to claim 3, wherein the separation sensor is provided near a downstream side of a contact position between the sheet feeding roller and the rotating body.   2. The sheet feeding device according to claim 1, wherein the feeding roller and the sheet feeding roller are connected to the same rotational drive source via independent clutches, and are alternately switched between a sheet feeding operation and a stopping operation.

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