JPH10338391A - Paper feeding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To execute paper bent attitude correcting action positively and easily and reduce manufacturing cost through the disuse of an expensive electromagnetic clutch and attain silence without noise such as impact noise generated during the operation of the electromagnetic clutch. SOLUTION: This paper feeding device has a paper feeding means 20, a driving means for driving the paper feeding means 20, and a control means for controlling driving of the driving means. The paper feeding means 20 delivers paper D stacked on a paper feeding plate 11 by a delivery means, separates a sheet of paper D by a separating means to feed it and refeeds paper after arranging the attitude of a sheet of paper by a register roller pair to make it stand by. In this case, a sheet of paper D is separated and fed by the rotation of the delivery means and separating means by normal rotatory- driving of one driving motor M2 provided at the driving means, and made to butt against the outer peripheral surface of a register roller pair in a stop state to correct the bend of a sheet of paper and to make it stand by. The driving motor M2 is then switched to reverse driving by the control means, and the register roller pair is rotatory-driven to refeed the paper D.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper feeding means of an automatic document feeder attached to a recording device such as an electrophotographic copying machine or an image reading device, a paper feeding cassette, a large capacity paper feeding device or the like. And a paper feeding device such as a paper re-feeding unit that feeds out from a stacker that stores recorded paper for backside recording.

[0002]

2. Description of the Related Art Each paper feeder separates and feeds one sheet from a paper feed tray (stacker) that stores a plurality of sheets, and feeds it to the next step.

For example, an automatic document feeder includes a paper feed tray, paper feed means, transport means, and paper discharge means. The paper feed tray includes a document loading table on which a plurality of document sheets are loaded, and a movable sheet width regulating plate that aligns the width direction of the document sheets. The sheet feeding means separates and feeds one sheet of the document sheet from the sheet stack of documents placed on the sheet feed tray, and feeds the sheet to the image reading section on the exposure document table (platen glass). The conveying means conveys the document sheet fed to the image reading unit onto the platen glass by an endless belt or a roller rotatably provided above the platen glass, and stops at a predetermined image reading position. Then, the manuscript paper after the image reading is carried out. The paper discharging means discharges the original paper conveyed from the conveying means to a paper discharging tray or the paper feed tray. Alternatively, the original sheet conveyed out of the conveying means is turned upside down, conveyed again onto the platen glass, and an image on the back surface of the original is read.

In general, a paper feeder that separates and feeds one sheet of paper stacked on a paper feed tray on which paper is stacked includes:
Feeding means comprising a pickup roller for feeding out the paper stacked on the paper feeding tray and a movable pressing plate; a feed roller and a reverse roller for separating and feeding one sheet from the paper fed by the feeding means; Roller), a pair of registration rollers for adjusting the posture of one sheet separated and fed by the separating unit, holding the sheet, and then re-feeding the sheet according to a sheet feeding start signal, and driving these units. And driving means for controlling the driving of the driving means.

[0005]

The paper feeder having the above configuration has the following problems.

(1) At the time of paper feeding in the paper feeding device, the paper fed by the feeding means and the separating means abuts on the outer peripheral surface of the registration roller pair whose rotation has been stopped, and the paper is bent. After being corrected and waiting,
The registration roller pair is rotated by the sheet feeding start signal, and the sheet is fed again.

In the correction of the posture of the sheet, the stop of the registration roller pair and the switching between the normal rotation and the forward rotation have conventionally been performed by using an electromagnetic clutch. Switching by this electromagnetic clutch increases the manufacturing cost due to the use of an expensive electromagnetic clutch, generates noise such as impact noise when the electromagnetic clutch is operated, and is fed onto the platen glass by rotation of a pair of registration rollers. There is a problem that the stop position of the original sheet is uncertain.

(2) In the conventional paper feeding apparatus, the movable pressing plate for pressing the pickup roller of the feeding means is used until the leading end of the fed paper reaches the pressure contact position between the feed roller and the reverse roller of the separating means. Pressing.
However, the sheet feeding operation of the feed roller may be inferior to the sheet returning operation of the reverse roller that is in pressure contact with the feed roller, and the leading end of the sheet may not reach the registration roller pair, and a sheet feeding failure may occur.

(3) If the peripheral speed of the pickup roller and the peripheral speed of the feed roller are constant, the paper stretched between the pickup roller and the feed roller causes a load on the feed roller, and the load on the feed roller causes the load. The separation and feeding of paper becomes uncertain.

(4) When the pair of registration rollers is rotated by the reverse rotation of the drive motor to feed the paper and the reverse roller is also rotated, the paper is returned by the reverse rotation of the reverse roller, and the leading end of the paper is registered. There is a case where the sheet is not fed by the registration roller away from the nip position of the roller, which causes a sheet feeding failure.

[0011]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has various problems at the time of paper feeding, paper separation and feeding, and paper registration in various paper feeding devices. And stabilization.

According to a first aspect of the present invention, there is provided a sheet feeding apparatus for feeding sheets stacked on a sheet feeding tray by a feeding unit, and separating and feeding one sheet by a separating unit. Paper feeding means for feeding and adjusting the posture of one sheet by a pair of registration rollers, and re-feeding the paper; driving means for driving the paper feeding means; and control means for controlling the driving of the driving means. In the paper feeding device, one sheet of paper is separated and fed by the rotation of the feeding unit and the separating unit by the normal rotation drive of one drive motor provided in the driving unit,
The stoppage of the registration roller pair is abutted against the outer peripheral surface to correct the bending of one sheet of paper, and the standby is performed.Next, the control motor switches the driving motor to the reverse rotation drive, and drives and rotates the registration roller pair. The paper is fed again.

According to a third aspect of the present invention, which achieves the above object, a sheet stacked on a sheet tray is provided.
A sheet feeding unit that sends out the sheet by the sending unit, separates and feeds the sheet by the separating unit, adjusts the posture of the sheet by the registration roller pair, and re-feeds the sheet, and drives the sheet feeding unit. In a sheet feeding device having a driving unit and a control unit for controlling the driving of the driving unit, the feeding unit includes a pickup roller that is normally rotated by the driving unit, and a leading end of a sheet stacked on a sheet tray. A movable pressing plate that can be placed and pressed against the pickup roller from below and that can move up and down until the leading end of the paper reaches the nip position of the registration roller pair via the separation unit.
The movable pressing plate presses the sheet.

Further, according to a fourth aspect of the present invention, which achieves the above object, a sheet loaded on a sheet tray is provided.
A sheet feeding unit that feeds out one sheet by a feeding unit, separates and feeds one sheet by a separating unit, adjusts a posture of one sheet by a pair of registration rollers, and re-feeds the sheet, and drives the sheet feeding unit. In a sheet feeding device having a driving unit and a control unit for controlling the driving of the driving unit, the feeding unit includes a pickup roller that is normally rotated by the driving unit, and a leading end of a sheet stacked on a sheet tray. A movable pressing plate which can be placed and pressed from below to the pickup roller side, and which can be moved up and down, wherein the separating means comprises a feed roller which rotates forward by a driving means and a reverse roller which can rotate reversely, The peripheral speed is set to be higher than the peripheral speed of the feed roller.

Further, in the paper feeder according to the present invention, the paper loaded on the paper feed tray is sent out by a feeder, and the paper feeder and the reverse roller are provided. Feeding means for separating and feeding one sheet of paper by means, adjusting the posture of one sheet of paper by a pair of registration rollers, and re-feeding the paper, driving means for driving the paper feeding means, and the driving means Control means for controlling the driving of the paper feeder, a coupling for generating idle time between forward rotation and reverse rotation is provided in the drive transmission path of the drive means, and when the drive motor is driven in reverse rotation, After a lapse of several milliseconds from the start of rotation of the registration roller pair, the reverse roller starts reverse rotation via the coupling.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the paper feeder according to the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a cross-sectional view of an automatic document feeder to which the present invention can be applied, and FIG. 2 is a cross-sectional view of a paper feed unit of the automatic document feeder.

The illustrated automatic document feeder (hereinafter, also referred to as ADF) is configured to transfer a plurality of original sheets (single-sided original sheets or double-sided original sheets, hereinafter, referred to as originals) D to an original loading table of the original loading section 10. The paper is fed from above by a paper feeding unit 20, conveyed by a conveying unit 30, and subjected to an exposure process on a document mounting table (platen glass) 101 of the image reading apparatus main body or the copying machine main body 100. After that, the ADF to be discharged onto the discharge tray 49 by the discharge means 40
Mode and the original D after the exposure
R-ADF mode in which the original D is discharged from above, the original D is turned over, and the original D is conveyed to the platen glass 101 again and the exposed original D is discharged onto the discharge tray 49.

The ADF includes an original stacking unit 10, a paper feeding unit 2,
0, transport means 30, and paper discharge means 40.

The document stacking section 10 is mounted on the ADF main body, and is capable of stacking the documents D thereon, and a movable sheet width regulating plate 12 for aligning and regulating the width of the placed documents D.
Consisting of The paper width regulating plate 12 regulates the document D in the document width direction on the basis of one side or the center.

At the leading end of the paper feed tray 11 on the downstream side of the original feeding,
A document leading end stopper 201, an upper guide plate 202, a lower guide plate 203, and a movable pressing plate 204, which is swingably supported and whose leading end can be raised and lowered, are provided near the entrance of the paper feeding means 20. I have. A plurality of originals D are placed on the paper feed tray 11, and the leading end of the original D is passed over the movable pressing plate 204, hits the original leading end stopper 201 and is stopped. When the original D is loaded, the leading end of the original D flips up the swingable actuator 205 to transmit an ON signal from the original set detection sensor PS1, and the ADF mode is set.

The movable pressing plate 204 is driven by a pressing motor (DC motor) M1 via a cam (not shown) and can swing about a swing shaft 206. Movable pressing plate 2
The ascending position (pressing position) and the descending position (initial position) of 04 are positioned by drive control of the pressing motor M1 from the initial position detection by the movable pressing plate position sensor PS2.

A movable pressing plate 204 and a pick-up roller 2 for sending out the original D by driving and rotating while pressing against the movable pressing plate 204 are provided upstream of the original feeding of the paper feeding means 20.
07 is provided. On the downstream side of the pickup roller 207, there is provided a separation / feed roller pair (separation means) including a feed roller 208 that is driven and rotated and a reverse roller (separation roller) 209 that is in pressure contact with the feed roller 208. On the further downstream side of the separation / feed roller pair, there are provided a registration roller 210 that is driven and rotated, and a registration pinch roller 211 that is pressed against the registration roller 210 and is driven to rotate.

The pickup roller 207, feed roller 208, reverse roller 209, and registration roller 210 are driven and rotated by a paper feeding motor (stepping motor) M2.

A passage sensor PS3 for detecting passage of the document D is provided upstream of the registration roller 210 in the paper feed path. A registration sensor PS4 is provided downstream of the registration roller 210.

FIG. 3 is a sectional view showing a drive system (drive means) of the paper feed means of the automatic document feeder. In addition, for convenience of explanation, each of the rotating shafts and the driving members is a sectional view developed in a plane. FIG. 4 is a front view of the drive system. In the drawings, driving members such as gears, timing pulleys, and timing belts are indicated by alternate long and short dash lines.

A gear G1 and a timing pulley TP1 are fixed to the drive shaft of the sheet feeding motor M2 which can rotate forward and backward. The timing pulley TP1 is a timing belt T
Drive shaft 212 of pickup roller 207 via B1
And the timing pulley TP2, which is integral with the motor, is rotatable. One-way clutch K for timing pulley TP2
1 when the motor M2 rotates forward, the driving force is transmitted so that the pickup roller 207 rotates forward. When the motor M2 rotates reversely, the pickup roller 2 rotates.
No driving force is transmitted to 07.

A timing pulley TP3 is provided near the both sides of the pickup roller 207 on the axis of the drive shaft 212. The timing pulley TP3 is driven by the driven shaft 213 of the feed roller 208 via the timing belt TB2.
And a timing pulley TP4, which is integral with the second pulley, is made rotatable.

Drive shaft 2 near timing pulley TP3
A one-way clutch K6 is provided at 12, and a one-way clutch K7 is provided at one end of the driven shaft 213 near the timing pulley TP4. Further, a one-way clutch K8 is provided at the other end of the driven shaft 213 as a bearing.

When the registration roller 210 rotates forward to feed one original D, and at the same time, the reverse roller 209 rotates backward to prevent double feeding of the subsequent original D, the original D is fed. When the rear end passes through the nip position of the reverse roller 209 and exits, the feed roller 2 presses against the reverse roller 209 by the reverse rotation of the reverse roller 209.
08 rotates in the reverse direction, and at the same time, the pickup roller 207 connected to the feed roller 208 by the timing belt TB3 also rotates in the reverse direction and acts in a direction to return the leading end of the following document D. When the document D is conveyed in the reverse direction by a large number of sheets, the leading end of the document D is displaced from the sheet feeding pressure point of the pickup roller 207, so that the subsequent document D cannot be fed, resulting in a sheet feeding failure.

By providing a one-way clutch K8 on the driven shaft 213 of the feed roller 208, the feed roller 208 follows the reverse rotation of the reverse roller 209 and rotates.
Is prevented from rotating in the reverse direction, and is held in a stopped state, so that the document D is prevented from returning backward.

On the other hand, the gear G1 is
Meshes with a gear G2 fixed to the shaft end of the drive shaft 214,
The driving rotation is transmitted to the registration roller 210. Gear G2
Has a built-in one-way clutch K2, which transmits a driving force so that the registration roller 210 rotates forward when the motor M2 rotates forward, and when the motor M2 rotates reversely.
No driving force is transmitted to the registration roller 210.

A gear G3 is formed integrally with the gear G2. The gear G3 meshes with a gear G4 rotatably fitted to a fixed intermediate shaft 215 implanted in a side plate of the ADF main body,
Transmits forward rotation. On the central axis of the fixed intermediate shaft 215,
A gear G5 is rotatably supported adjacent to the gear G4. The gear G4 and the gear G5 are connected by coupling means, and the forward rotation and the reverse rotation from the gear G4
5 is transmitted.

FIG. 5A is a perspective view showing a coupling means composed of a gear G4 and a gear G5, FIG. 5B is a front view at the time of forward rotation, and FIG. 5C is a front view at the time of reverse rotation. It is.

On the side of the gear G5 facing the gear G4,
Two pins 216 are implanted. On the side of the gear G4 facing the gear G5, two arc-shaped long grooves 217 that allow the pin 216 to move in the circumferential direction are formed in two places.

When the gear G4 rotates forward, FIG.
As shown in (b), the pin 216 contacts one end of the long groove 217 of the gear G4 to transmit the driving force so that the gear G5 rotates clockwise in the forward direction.

When the gear G4 switches from the forward rotation to the reverse rotation, as shown in FIG.
After the gear 16 comes into contact with the other end of the long groove 217 of the gear G4 from the position at the time of the forward rotation (the position shown in FIG. 5B), the driving force is transmitted so as to rotate the gear G5 counterclockwise. I do.
When the gear G5 rotates in the reverse direction, the pin 216 is
There is a play time difference (several milliseconds) from one end to the other end of the long groove 217.
, The start of rotation of the gear G5 is delayed.

Accordingly, the reverse roller 209 connected to the gear G5 starts reverse rotation a few milliseconds after the registration roller 210, which rotates simultaneously with the gear G4, starts rotating. By providing such a time lag, after the registration roller 210 starts rotating and reliably feeds the leading end of the document D with the registration pinch roller 211 and starts feeding, the reverse roller 209 starts reverse rotation. Since the following document D is returned to prevent double feeding, the feeding property of the document D is improved.

Next, the gear G5 is connected to the reverse roller 209.
Is meshed with a gear G6 provided at the shaft end of a drive shaft 218 that drives the motor. The gear G6 includes a one-way clutch K3. A gear G7 is fixed on the shaft of the drive shaft 218, and the gear G7 is connected to a gear G9 via an idle gear G8.
Connected to The gear G9 is integrated with a torque limiter 220 rotatably supported by the fixed support shaft 219, and rotates the reverse roller 209 with a predetermined torque.

A timing pulley TP5 fixed to a drive shaft 212 for driving the pickup roller 207 applies a driving force to a timing pulley TP6 provided adjacent to the gear G6 at the shaft end of the drive shaft 218 via a timing belt TB3. introduce. The one-way clutch K4 is incorporated in the timing pulley TP6.

By providing the one-way clutches K3 and K4 on the drive shaft 218 of the reverse roller 209, the reverse roller 2 can be driven regardless of the forward / reverse rotation of the sheet feeding motor M2.
The one-way rotation drive is transmitted to 09.

The reverse roller 209 is a torque limiter 2
The document D is driven in a direction opposite to the traveling direction of the document D via the press roller 20, and is pressed against the feed roller 208 by an initial pressure by a pressure spring (not shown) and an operating pressure generated by the torque of the torque limiter 220. Reverse roller 2
Reference numeral 09 denotes a state in which the feed roller 208 slips beyond the limit torque of the torque limiter 220 when it comes into direct contact with the feed roller 208 (when there is no original D between the nips) or when one original D is fed between the nips. It rotates following the rotation of. However, when two or more documents D are fed between the nips, the limit torque of the torque limiter 220 overcomes the frictional force between the documents D, rotates the reverse roller 209 in the reverse direction, and pushes back the lower document D, Double feed is prevented.

FIG. 6 is a front view of a main part of the paper feeding means 20.

Drive shaft 212 of pickup roller 207
And a timing pulley TP3 fixed to the driven shaft 213 of the feed roller 208, the endless timing belt T
B2 is stretched. In the present invention, the number Z1 of teeth of the timing pulley TP3 is set to 19, the number Z2 of teeth of the feed roller 208 is set to 209, and the outer diameter of the pickup roller 207 is set to 21 mm.
Assuming that the outer diameter of the pickup roller 20 is 20 mm, the pickup roller 20
7 is about 5% (20/19 = about 1.05) by a gear difference and 5% (21/20 = 1.05) by an outer diameter difference from the feed amount of the document D by the feed roller 208. ),
Totally increases by about 10%.

Therefore, in the document feed path from the position where the document D is sent out by the pickup roller 207 and the movable pressing plate 204 to the nip position between the feed roller 208 and the reverse roller 209, the difference between the feed amounts of the two rollers is Document D forms a deflection.

The pickup roller 207 and the feed roller 208 start rotating and start feeding the document D. After a lapse of a predetermined time after the leading end of the document D has passed through the passage sensor PS3, the registration roller 210 is nipped. It rotates until it reaches a position slightly past the position. In the document feeding process, the pickup roller 207 and the feed roller 20
8, a deflection is formed in the document D due to the difference in the feeding amount. Therefore, when the document is fed by the feed roller 208, the feed roller 208 draws the document between the pickup roller 207. The load is eliminated.

In FIG. 6, the timing pulley T
A high friction material having a high friction coefficient was formed on the back surface (outer peripheral surface) of the timing belt TB2 stretched between P3 and the timing pulley TP4. As a high friction material,
For example, ethylene-propylene rubber (EPDM), acrylonitrile-butadiene rubber (NBR), chloroprene rubber (CR), butadiene rubber (BR), styrene-
It is selected from butadiene rubber (SBR), butyl rubber (IIR), isoprene rubber (IR), natural rubber (NR) and the like. Further, the outer periphery of the high friction material has an appropriate surface roughness.

Pickup roller 207 and movable pressing plate 2
04 and the feed roller 2
When the document D having a large curl is fed in the document feed path reaching the position where the document D and the reverse roller 209 are sandwiched, the pickup roller 207 alone moves the leading edge of the document D to the position where the feed roller 208 and the reverse roller 209 are sandwiched. The part may not be able to feed. However, by using the timing belt TB2 made of the high friction material, the leading end of the document D sent out by the pickup roller 207 comes into contact with the outer peripheral surface of the timing belt TB2 and is held by the high friction coefficient. The feeding force is increased, and the sheet is reliably fed to the position where the feed roller 208 and the reverse roller 209 are nipped.

The transport belt 31 shown in FIG. 1 includes a driving roller 32, a driven roller 33, and original pressing rollers 34, 3
5A, 35B, 35C and the tension roller 36 are rotatably stretched. The drive roller 32 is a timing pulley TP that is driven and rotated from a transport motor (stepping motor) M3 via a timing belt TB5.
Integrates with 7.

The document D fed from the paper feeding means 20 to the transport means 30 is moved on the platen glass 101 by the transport belt 31 and after the passage of the trailing edge of the document by the registration sensor PS4 is detected, After a lapse of a predetermined time, the transport belt 31 stops rotating. Conveyor belt 3
Numeral 1 reverses rotation immediately after stopping, and stops rotating when the rear end of the document D abuts against the document stopper 102. When the original is stopped, the original D is scanned by the exposure optical system.
Is read. The exposed original D is
The paper is sent to the paper discharging means 40.

The document D sent to the sheet discharging means 40 by the conveyor belt 31 is detected by the sheet discharging sensor PS5 to pass the leading edge of the document, and is sent to a position where the sheet reversing roller 41 and the sheet discharging roller 42 are sandwiched. The paper passes through the passage of the paper guide plate, is conveyed while being nipped by the paper ejection reversing roller 41 and the paper ejection roller 43, and in the ADF mode of a single-sided original, the passage between the guide plate 46 and the upper surface of the switching claw 45. , And is discharged out of the apparatus by the discharge rollers 44 and placed on the discharge tray 49. The paper discharge sensor PS5 detects the passage of the leading edge of the document and the jam detection.

In the R-ADF mode for a two-sided original, the switching claw 45 is driven by the solenoid SD, the transport path of the original D is switched, and the original is held between the transport belt 31 and the platen glass 101 switched to the reverse rotation drive. Then, the sheet is reversed on the platen glass 101 and abuts against the document stopper 102 to stop. In this original stopped state, the image on the back side of the original D is read by scanning exposure by the exposure optical system. The exposed document D is discharged out of the apparatus by the paper discharging means 40 in the same manner as in the ADF mode.

Hereinafter, the document feeding control of the sheet feeding means of the automatic document feeder according to the present invention will be described.

FIG. 7 is a block diagram showing the main part of the drive system control of the paper feeding means of the automatic document feeder.
Control of each operation of document reversal conveyance, conveyance, and paper discharge is all performed by control means (CPU) 60. That is, the leading end of the document D separated and fed from the paper feeding unit 20 is detected by the document set detection sensor PS1, the movable pressing plate position sensor PS2, the passage sensor PS3, and the paper feeding sensor PS4, and input to the control unit 60. . The document D fed from the paper feeding means 20 is transported by the rotating conveyor belt 31 to the platen glass 1.
After sliding on the sheet No. 01 and after the exposure processing, the passage of the leading end of the document is detected by a sheet discharge sensor PS5 provided on the sheet discharge means 40 side, and is input to the control means 60. These input signals are processed by the control means 60 to control the driving of the motors M1 to M4.

FIG. 8 is a flowchart showing the paper feeding process of the paper feeding means 20, and FIG. 9 is a timing chart showing the control of the paper feeding means 20.

(1) The original bundle D is stacked on the paper feed tray 11 and the movable pressing plate 204, and the leading end of the original is
When the contact is made, the original set detection sensor PS1 is turned on, and the ADF mode is displayed on the operation panel.

(2) When the copy start button is pressed, the document feed start signal is received and the control of the paper feed means is started. That is, in response to the document feed start signal, the pressing motor M1 starts driving and rotating, and the movable pressing plate 204 is moved by the cam to the swing shaft 2.
06, and the leading end of the movable pressing plate 204 rises up to the pressure contact position with the pickup roller 207.
The original bundle D is pressed. When the rise of the movable pressing plate is detected by the movable pressing plate position sensor PS2, the driving of the pressing motor M1 is stopped, and the pressure contact is continued.

(3) When the driving of the pressing motor M1 is stopped, the normal rotation of the paper feeding motor M2 is started, the normal rotation of the pickup roller 207, the feed roller 208, and the registration roller 210 is started, and the original D is moved. Start feeding,
One document D is separated and fed.

(4) When the leading end of the document D separated and fed from the nipping position between the feed roller 208 and the reverse roller 209 passes through the registration sensor PS4, the passing signal indicates that the sheet feeding motor M2 by the pulse counter. The pulse count C1 starts counting, and the document D is fed.

(5) The sheet feeding motor M2 is decelerated and stopped by counting up the pulse count C1.

(6) After counting up the pulse count C1, the sheet feeding motor is stopped for a predetermined time T1, and then the sheet feeding motor M2 starts to rotate forward again. At the same time, the normal rotation drive of the transport motor M3 is started.

(7) Pass sensor P for passing the rear end of document D
S3 detects and generates an off signal, and the pulse counter C2 to the transport motor M3 by the pulse counter starts counting.

(8) The transport motor M3 is decelerated and stopped by counting up the pulse count C2. At the same time, the feed motor M2 is decelerated and stopped. With the above operation, the first document feeding is completed.

(9) The first document is the platen glass 10
While the exposure processing is performed on the first surface and the sheet is sent to the sheet discharging means 40, the preliminary feeding of the subsequent second document is started.

FIG. 10 is a plan view showing a sheet feeding operation by the sheet feeding means 20 of the present invention.

The original D is fed to the nipping position between the registration roller 210 and the registration pinch roller 211 by the forward rotation of the paper feeding motor M2, passing through the pickup roller 207 and the feed roller 208. At this time, since the registration roller 210 is not rotating as shown in the above (6), a part of the leading end surface of the original D fed at an angle is positioned between the registration roller 210 and the registration pinch roller 211. (See FIG. 10 (a)).

When the feed amount of the original D is smaller than the registration roller 2
10 is larger than the nipping position, so that the pickup roller 2
07 and the forward rotation of the feed roller 208, the leading end surface of the document D is pushed in the feeding direction,
A tangent line between the position of the original D and the pinch roller 211 is parallel to the leading end surface of the document D (see FIG. 10B).

Next, the registration roller 210 is rotated by the reverse rotation of the paper feed motor M2, and the registration roller 210 rotates to feed the leading end of the original D parallel to the tangent line of the nipping position. Therefore, the original D is bent and sent to the platen glass 101 (FIG. 10C).
reference).

As described above, the one-way clutch K provided on the drive shaft 212 of the pickup roller 207
1, a one-way clutch K2 provided on the drive shaft 214 of the registration roller 210, and one-way clutches K3 and K4 provided on the drive shaft 218 of the reverse roller 209.
Due to the forward / reverse switching control of No. 2, the original D fed at an angle is corrected at the position where the registration roller 210 is nipped, so that the original D is accurately fed to the platen glass 101.

The paper feeder of the present invention is applicable to a manual paper feeder for recording paper, a paper intermediate stacker of a double-sided recording apparatus, and the like, in addition to the paper feeder of the automatic document feeder.

[0071]

According to the paper feeding device of the present invention, the operation of correcting the paper sheet skew can be reliably and easily performed by switching between the forward and reverse rotations of the driving shaft having the one-way clutch and the paper feeding motor. Be executed. In addition, since an expensive electromagnetic clutch is not used, it is effective in reducing the manufacturing cost, and noise reduction such as an impact sound generated when the electromagnetic clutch is operated can be achieved.

Further, in the paper feeder according to the third aspect of the present invention, the original is pressed by the movable pressing plate below the pickup roller until the paper reaches the holding position of the registration roller.
Feeding failure in which the paper does not reach the registration rollers is prevented.

Further, in the paper feeder according to claims 4 to 7 of the present invention, since the paper feed amount of the pickup roller is larger than the paper feed amount of the feed roller, the feed roller feed operation is less than the reverse roller return operation, and Feeding failure that the paper does not reach the registration roller is prevented.

Further, in the paper feeder according to the ninth to tenth aspects of the present invention, the reverse rotation of the reverse roller is started via the coupling after a lapse of several ms from the rotation of the registration roller. The reverse rotation of the reverse roller causes the registration roller pair and the reverse roller to rotate at the same time, so that the paper is returned by the reverse rotation of the reverse roller, and the leading edge of the paper is separated from the pinching position of the registration roller, and The occurrence of a paper feeding failure, in which the paper is not fed, is prevented, and the paper feeding property is improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an automatic document feeder to which the present invention can be applied.

FIG. 2 is a cross-sectional view of a sheet feeding unit of the automatic document feeder.

FIG. 3 is a cross-sectional view illustrating a driving system of a sheet feeding unit of the automatic document feeder.

FIG. 4 is a front view of the drive system.

FIG. 5 is a perspective view showing the coupling means, a front view at the time of normal rotation, and a front view at the time of reverse rotation.

FIG. 6 is a front view of a main part of a sheet feeding unit.

FIG. 7 is a block diagram showing a main configuration of a drive system control of a paper feeding unit of the automatic document feeder.

FIG. 8 is a flowchart illustrating a sheet feeding process of a sheet feeding unit.

FIG. 9 is a timing chart illustrating control of a sheet feeding unit.

FIG. 10 is a plan view showing a sheet feeding operation by sheet feeding means.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 Document loading section 11 Document loading table (feed tray) 12 Paper width regulating plate 20 Paper feeding means 201 Document leading end stopper 204 Movable pressing plate 207 Pickup roller 208 Feed roller 209 Reverse roller (separation roller) 210 Registration rollers 212, 214, 218 Drive shaft 213 Follower shaft 216 Pin 217 Long groove 220 Torque limiter 30 Conveying means 31 Conveying belt 40 Discharge means 50 Control means 101 Document placing table (platen glass) D Document (paper) C1, C2 Pulse count K1 to K8 One-way clutch M1 , M2, M3, M4 Motor TP1 to TP7 Timing pulley TB1 to TB5 Timing belt PS3 Passage sensor PS4 Registration sensor

Claims (10)

[Claims] 1. A sheet loaded on a sheet feed tray is sent out by a feeding means, one sheet is separated and fed by a separating means, and after adjusting a posture of one sheet by a pair of registration rollers. A sheet feeding device having a sheet feeding unit for re-feeding a sheet, a driving unit for driving the sheet feeding unit, and a control unit for controlling the driving of the driving unit; The sheet is separated and fed by the rotation of the sending-out means and the separating means by the normal rotation drive,
The stoppage of the pair of registration rollers is abutted against the outer peripheral surface to correct the bending of one sheet of paper, and the standby is performed. A sheet feeding device for re-feeding the sheet. 2. A one-way clutch is mounted on each drive shaft of the delivery unit, the separation unit, and the registration roller pair, and the delivery unit, the separation unit, and the registration roller pair are rotated forward and backward with respect to forward and reverse rotations of the drive motor. The paper feeding device according to claim 1, wherein the paper feeding device is turned or stopped. 3. A sheet stacked on a sheet feeding tray is sent out by a feeding means, one sheet is separated and fed by a separating means, and after adjusting a posture of one sheet by a pair of registration rollers. In a sheet feeding device having a sheet feeding unit for re-feeding a sheet, a driving unit for driving the sheet feeding unit, and a control unit for controlling driving of the driving unit, the feeding unit includes:
The pickup roller is configured to include a pickup roller that rotates forward by a driving unit, and a movable pressing plate that can move up and down to place the leading end of the paper stacked on the paper feeding tray and press the leading end of the paper toward the pickup roller from below. A sheet feeding device, wherein the movable pressing plate presses the sheet until the sheet reaches the nip position of the pair of registration rollers via the separating unit. 4. A sheet stacked on a sheet feeding tray is sent out by a feeding means, one sheet is separated and fed by a separating means, and a posture of the one sheet is adjusted by a pair of registration rollers. In a sheet feeding device having a sheet feeding unit for re-feeding a sheet, a driving unit for driving the sheet feeding unit, and a control unit for controlling driving of the driving unit, the feeding unit includes:
A pickup roller that rotates forward by a driving unit, and a movable pressing plate that can move up and down to place the leading end of the paper stacked on the paper feed tray and press the pickup roller side from below, and the separation unit is driven. A feed roller that rotates forward by means and a reverse roller that can rotate reversely, wherein a peripheral speed of the pickup roller is set to be higher than a peripheral speed of the feed roller. 5. The pickup roller and the feed roller are connected by drive transmission means, and the number of teeth of the drive transmission member of the feed roller is set to be greater than the number of teeth of the drive transmission member of the pickup roller. The paper feeding device according to claim 4. 6. A timing pulley provided on the pickup roller and the feed roller, wherein the drive transmission means comprises:
5. A timing belt stretched between the timing pulleys, wherein the number of teeth of the timing pulley of the feed roller is set to be larger than the number of teeth of the timing pulley of the pickup roller.
Or the paper feeding device according to 5. 7. The drive transmission means comprises a gear provided on the pickup roller and the feed roller, and an intermediate gear meshing with the gear, wherein the number of teeth of the gear of the feed roller is set to the gear number of the pickup roller. The number of teeth is set larger than the number of teeth.
A paper feeder according to claim 1. 8. The drive transmission means comprises a gear provided on the pickup roller and the feed roller, and an intermediate gear meshing with the gear, wherein the number of teeth of the gear of the feed roller is set to the gear number of the pickup roller. The sheet feeding device according to claim 4, wherein the number of teeth is set to be larger than the number of teeth, and the outer diameter of the pickup roller is set to be larger than the outer diameter of the feed roller. 9. A sheet stacked on a sheet feeding tray is sent out by a feeding means, one sheet is separated and fed by a separating means comprising a feed roller and a reverse roller, and one sheet is fed by a pair of registration rollers. A paper feeding device for re-feeding the paper after adjusting the paper posture, a driving device for driving the paper feeding device, and a control device for controlling the driving of the driving device. In the drive transmission path,
A coupling is provided for generating a play time between forward rotation and reverse rotation, and during the reverse rotation of the drive motor, after the registration roller pair starts rotating, after a lapse of several milliseconds, via the coupling. A sheet feeding device, wherein the reverse roller starts reverse rotation. 10. The paper feeder sends out original sheets stacked on the paper feed tray by the feeder,
Separating and feeding one document sheet by the separating means,
2. A sheet feeding means of an automatic document feeder for adjusting the posture of one sheet of original paper by the pair of registration rollers, waiting the original paper, re-feeding the original paper, and feeding the original paper onto a platen glass. 9. The sheet feeding device according to any one of items 1 to 8, wherein