JPH07237774A - Paper feeding device - Google Patents

Abstract

PURPOSE:To improve the reliability in the skew correction by permitting the first and the second rollers to be set with high precision, by installing the second roller in an advance/retreat manner for the first roller, on the first frame through the second frame, and allowing the second roller to be urged to the first roller side by an urging means. CONSTITUTION:When the first original document placed on the original document tray 61 of the automatic original document feeder of a copying machine is supplied, a pressing plate 70 transfers downward from a retreat position, and the top end part of the original document is pressed to a pick-up roller 65, and is applied with a paper feed pressure. By the turn in the clockwise direction of the pick-up roller 65 and an assorting roller 75, the original documents pass one by one from the lowest layer through between the assorting roller 75 and an assorting pad 80, and are sent to a resist roller 90. In an original, document feeding part 601 a resist driven roller 90b is urged to a resist driving roller 90a by a spring 174C, and the cams 171a and 172a are engaged with the eccentric cams 171b and 172b, and the press contact at the resist roller 90 is released.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copying machine, an automatic document feeder attached to the copying machine, a printer, a facsimile, and the like, and a paper feeding device for feeding a printing sheet and a document.

[0002]

2. Description of the Related Art Conventionally, as the above-mentioned paper feeding device, FIGS.
The one shown in 1 is known. In this paper feeding device 700, a plurality of sheets (not shown) introduced along the guide plate 701 are provided with a separating roller 702 that applies a conveying force to the lower surface of the sheet, and a separating pad 703 that is pressed against the separating roller 702. Are separated and sent out one by one. The sheet that has passed through the pressure contact portion between the separation roller 702 and the separation pad 703 is conveyed while being guided by the guide plates 701 and 704, is introduced into the nip portion between the registration driving roller 705 and the registration driven roller 706, and is in contact with the nip portion. In the contact state, it is temporarily stopped and is further conveyed to a predetermined processing area (for example, a printing area or an image reading area) by the rotation of the registration driving roller 705 in synchronization with the image processing of a copying machine or the like.

The sorting pad 703 and the guide plate 704
To remove the jammed sheet in the paper path,
A cover 708 rotatably supported around a fulcrum 707.
By fixing the guide plate to the guide plate 704 and supporting the separation pad 703 by the guide plate 704, the separation pad 703 and the registration driven roller 70 are opened and closed by opening and closing the cover 708.
6 is a separating roller 702 and a registration driving roller 7 respectively.
The paper passage path can be opened apart from 05.

[0004]

However, in the above-mentioned sheet feeding device 700, the pressure contact force between the registration driving roller 705 and the registration driven roller 706 is the same as that of the cover 708.
Therefore, a large force is required to lock the cover 708 at the closed position, and the operability of the cover 708 is poor. Further, the pressure contact force between the registration drive lock 705 and the registration driven roller 706 is influenced by the positional accuracy and the assembly accuracy of the fulcrum 707, and a uniform pressure contact force cannot be obtained over the entire length, and the skew (diagonal feed) correction accuracy is not obtained. There was a problem that was bad. Therefore, the present invention provides a sheet feeding device that can obtain a uniform pressure contact force over the entire length of both rollers without the lock of the cover being affected by the pressure contact force between the registration drive roller and the registration driven roller. To aim.

[0005]

In view of the above, the present invention provides a sheet feeding device including a first roller, a second roller which cooperates with the first roller to apply a conveying force to a sheet, and the second roller. A first frame that supports a first roller; a second frame that supports the second roller and is rotatably supported by the first roller via the second roller; Supporting means for supporting the first roller or the second roller so as to be able to move forward and backward with respect to the other, urging means for urging the first roller or the second roller toward the other roller, and the second frame. Is switched from the non-paper feed state to the paper feed state, the first roller and the second roller are pressed against each other, and the second frame is switched from the paper feed state to the non-paper feed state by the first roller and the second roller.
And a switching means for reducing the pressure contact force with the roller.

[0006]

In the paper feeding device having the above structure, the second roller is the second
The first frame supporting the first roller is provided via the frame of the above (1) so as to be able to move forward and backward with respect to the first roller, and is biased by the biasing means to the first roller.
Further, when the second frame is in the paper feeding state, the first roller and the second roller are brought into pressure contact with each other with a predetermined pressure contact force, and when the state is switched to the non-paper feed state, the pressure contact force between them is weakened.

[0007]

Therefore, according to the present invention, the pressure contact force between the first roller and the second roller is determined by the urging force of the urging means and does not affect the opening / closing force of the frame and its locking force. . Further, since the first roller and the second roller can be accurately set, the reliability of skew correction is enhanced.

[0008]

【Example】

<< Overall Configuration and Operation of Copying Machine >> FIG. 1 shows the overall configuration of the copying machine. A photoconductor drum 10 having a photoconductor layer on its outer peripheral portion is provided at a substantially central portion of the main body 1 of the copy machine. It is installed so as to be rotationally driven at a constant peripheral velocity v in the direction of arrow a. Around the photosensitive drum 10, along the rotation direction thereof, a main eraser 11, a charging charger 12, a sub-eraser 13, a magnetic brush type developing device 14, a transfer charger 15, a sheet separating charger 16, and a blade type cleaner 17 are provided. It is arranged. An optical system 20 is arranged above the photoconductor drum 10.

The photosensitive drum 10 rotates in the direction of arrow a, and the main eraser 11, the charging charger 12 and the sub-eraser 13 are used for static elimination, electrification and inter-image elimination.
The image edge is erased, and the image of the original set on the original glass 29 is exposed by the optical system 20. The electrostatic latent image formed on the photosensitive drum 10 by the exposure is visualized by the developing device 14 as a toner image.

The optical system 20 is arranged immediately below the original platen glass 29, and one end thereof is an exposure reference, that is, a reference position SP.
The original image set in accordance with is illuminated while being scanned, and the reflected light is exposed on the photosensitive drum 10.
During this image scanning, the exposure lamp 21 and the first mirror 22
And, move in the direction of arrow b at a speed of v / m (m: copy magnification) with respect to the peripheral speed v of the photosensitive drum 10 (constant regardless of equal magnification or variable magnification). At the same time, the second mirror 23 and the third mirror 24 move in the direction of arrow b at a speed of v / 2m.
When the copy magnification is changed, the projection lens 25 moves on the optical axis and the fourth mirror 26 swings or rotates to correct the optical path length.

A copy sheet, that is, a copy sheet, is provided with an upper elevator type paper feed unit 31 and a lower tray type paper feed unit 3.
It is accommodated in No. 4 and is fed one by one from any one of them according to the operator's selection. Each paper feed unit 31, 34
Paper feed rollers 32 and 35, and separation rollers 33 and 36 including a forward rotation roller and a reverse rotation roller are installed therein. The sheet fed from the upper sheet feeding section 31 is conveyed by the conveying rollers 37b, 3b.
It is sent out to the timing roller 38 installed immediately before the image transfer section through 7c. The sheet fed from the lower sheet feeding section 34 is sent out to the timing roller 38 through the transport rollers 37a, 37b, 37c.

In this copying machine, manual paper feeding is possible, and the copy paper inserted from the manual paper feeding port 40 is fed by a paper feeding roller 41.
To the timing roller 38. The sheet fed to the timing roller 38 once stands by here, and is fed to the transfer section by turning on the timing roller 38 in synchronization with the image formed on the photosensitive drum 10. The paper is in close contact with the photoconductor drum 10 at the transfer portion, and the toner image is transferred by the corona discharge from the transfer charger 15, and is separated from the photoconductor drum 10 by the AC corona discharge from the separation charger 16 and the stiffness of the paper itself. To be done. After that, the paper is conveyed on the conveyor belt
The toner is fixed by being sent to the fixing device 43 through 2 and is discharged onto the paper discharge tray 46 through the transport roller 44 and the discharge roller 45. On the other hand, the photoconductor drum 10 continues to rotate in the direction of the arrow a after the transfer, the cleaner 17 removes the residual toner, and the main eraser 11 erases the residual charge to prepare for the next copy process.

Inside the copying machine main body 1, there are installed a re-feeding unit 50 and paper-passing path switching claws 47 and 48 for processing double-sided / composite copying. The switching claw 47 is normally set to the solid line position and guides the paper to the paper discharge tray 46. During double-sided copying or composite copying, the paper on which the image of the odd-numbered original is transferred on the first surface (front surface) is set at a position where the switching claw 47 is slightly rotated counterclockwise, Conveying rollers 51a, 51b, 51
It is discharged to the intermediate tray 52 through the c and 51d, and is accommodated with the image surface facing upward. When a refeed signal is generated after a predetermined number of sheets of paper are stored on the intermediate tray 52,
The sheets are fed one by one to the conveying roller 37c from the lowermost one by the rotation of the re-feeding belt 53 and the separating roller 54.

In the double-sided copy mode, the re-fed paper is sent out to the timing roller 38 while being guided upward by the switching claw 48 set to the solid line position, and is then transferred to the second surface (back surface). The image is transferred, fixed, and discharged onto the paper discharge tray 46. On the other hand, in the composite copy mode, the re-fed paper is conveyed in the direction of arrow c by the conveyance roller 37d by setting the switching claw 48 to a position slightly rotated clockwise. Immediately before the trailing edge of the sheet exits the nip portion of the transport roller 37d, the transport roller 37d is switched to the reverse rotation, whereby the sheet is sent out to the timing roller 38 in a state where the front and back and front and back are reversed. After that, the images are transferred and fixed on the first surface (front surface) in an overlapping manner, and are discharged onto the paper discharge tray 46.

By the way, in the copying machine main body 1, the copying process is started, and the first sheet is the timing roller 3.
When waiting immediately before 8, the first-out paper feed process is performed in which the second and subsequent sheets are also fed in advance to the paper feed path. For example, in the paper feeding from the lower paper feeding unit 34, the second paper is fed to the paper feeding passage subsequent to the first paper, and the third paper is immediately before the transport roller 37a. Is fed. Such advance feeding processing is performed not only in the multi-copy mode but also in the single copy mode using the ADF 60 to improve the copy speed.

<< Structure and Operation of ADF >> The structure and operation of the ADF 60 will be described in detail. First, referring to FIG. 2, the ADF
The schematic configuration and operation of the 60 will be described in detail. ADF60 is
In general, it is composed of a document feeding unit 601, a document transporting unit 602, and a document discharging unit 603. The document feeding unit 601 is
Document tray 61, leading edge regulation plate 63, pickup roller 65, document pressing plate 70, separation roller 75, separation pad 8
0 and a registration roller 90, and parts other than the document tray 61 are covered with an openable / closable cover 604. The document transport unit 602 includes a drive roller 96 disposed near the document feed unit 601, a driven roller 97 disposed near the document discharge unit 603, and a transport belt 95, which are configured to move the document tray 61. It is covered with a constituting cover 605. The document discharge unit 603 includes a reversing roller 100, a discharge roller 110, and a paper discharge tray 115, and components other than the paper discharge tray 115 are covered with an openable / closable cover 606.

The ADF 60 is installed on the upper surface of the copying machine main body 1 so that the conveyor belt 95 is located on the original platen glass 29, and the original platen glass 29 is provided by a hinge metal fitting (not shown) provided on the back side, that is, the side opposite to the operating side. Can be opened to the upper surface of.

When the operator manually sets a document on the platen glass 29, the ADF 60 is lifted upward to open the upper surface of the platen glass 29. ADF60
1 is detected by the magnet sensor SE100 shown in FIG. 1, and the operation of the ADF 60 becomes possible only when the sensor SE100 detects that the ADF 60 is properly closed.

The originals to be fed are stacked on the original tray 61 with the first page facing upward. At this time, the position of the document is regulated in the width direction by the side regulating plate 62, and the position of the leading edge is regulated by the leading edge regulating plate 63. Tip regulation plate 6
3 and the pressing plate 70 are rotatable about the support shafts 64 and 71, respectively. The leading edge regulation plate 63 is retracted downward from the time of feeding the first document to the completion of feeding of the final document at the time of feeding. When the first original is fed, the pressing plate 70 moves downward from the retracted position shown in FIG. 2 and presses the leading end of the original against the pickup roller 65 to apply the feeding pressure.

Pickup roller 65, separation roller 75
Are driven to rotate in the clockwise direction during paper feeding. The originals pass through between the separating roller 75 and the separating pad 80 one by one from the lowest layer and are sent to the registration roller 90. The registration roller 90 temporarily holds the fed document at the nip portion thereof, and is rotated after a certain period of time to convey the document to the entrance portion of the document table glass 29.

The conveyor belt 95 is stretched endlessly between the driving roller 96 and the driven roller 97 so as to cover the entire surface of the original table glass 29. Inside the transport belt 95, a large number of backup rollers 98 are rotatably installed in order to press the belt 95 against the original table glass 29. The conveyor belt 95 is driven to rotate in the direction of arrow d, and is a reference position (exposure reference) SP for starting the exposure of the document, which is the boundary between the scale 120 and the document table glass 29.
Align the leading edge of the document with and set it.

In the vicinity of the reversing roller 100, pinch rollers 101 and 102, and a switching claw 103 for the purpose of switching the paper path for reversing the original in the double-sided original mode.
Is provided. Normally, the switching claw 103 is set to the solid line position, and after the exposure is completed, the document is discharged from the document table glass 29 based on the rotation of the conveyor belt 95 in the direction of arrow d and the rotation of the reversing roller 100 in the clockwise direction. The sheet is guided upward by the guide plate 104 and the switching claw 103, and is ejected onto the sheet ejection tray 115 by the ejection roller 110. In the case of a double-sided original, since the second side (back side) is subjected to copy processing first, when the double-sided original is fed onto the original platen glass 29,
The switching claw 103 is rotated in the clockwise direction by a predetermined angle from the state shown in the figure, and first, the double-sided original is fed to the reversing roller 100.
The sheet is reversely conveyed around the sheet and is returned on the platen glass 29 with the second surface facing downward. At this time, the conveyor belt 95 is rotationally driven in the direction opposite to the arrow d. Further, after the exposure of the second side of the double-sided original, the double-sided original is reversed and conveyed around the reverse roller 100 again for the copy processing of the first side (front side).

The reversing roller 100 and the discharging roller 11
Zero is rotationally driven by the discharge motor M4. ADF6
0 is various sensors SE1, SE2, SE for detecting the original
3, SE10 is provided. The sensor SE1 is the tray 61
The presence or absence of the above document is detected. The sensor SE2 is installed immediately before the registration roller 90, detects the arrival and passage of the original document, and detects the length of the original document in cooperation with the timer when the original document is sent out from the registration roller 90.
The sensor SE10 is installed side by side with the sensor SE2 and detects the size of the document in the width direction. Sensor SE2, SE10
On the basis of the document detection signal in (1), the size of the document is determined including whether the document is vertically fed (the long side of the document is parallel to the transport direction) or horizontally transported (the short side is parallel to the transport direction). Also, the sensor S
E3 is installed at the entrance of the reversing roller 100 and detects a document passing therethrough.

<< Explanation of Scale 120, etc. >> Scale 12
For 0, the ADF 60 is lifted and the original is placed on the original glass 29.
ADF60 is equipped with a scale for placing one end of the original according to its size when manually placing it on top.
In the above operation, the original has been conveyed on the original table glass 29 by the conveyor belt 95 and is forced to stop at the exposure reference position SP.

The scale 120 is arranged opposite to the downstream end of the original table glass 29 in the original conveying direction, and as shown in FIG. 3, holders provided on the back side and the front side of the upper frame 2 of the copying machine body 1. It is attached to 121 so as to be rotatable around a pin 122 as a fulcrum, and in a state in which a front end thereof, that is, the original table glass 29 side is biased upward by a spring 123.

The scale 120 has a projection 120a facing the upper surface frame 2 on the bottom and a document table glass 29.
Is provided with a protrusion 120b that protrudes into the lower space of the front end surface 120c. A plurality of cutouts 120e having a predetermined length are provided at the upper end corners.

As a result, the position of the scale 120 is regulated based on the urging force of the spring 123, with the projection 120b engaging with the lower surface of the document table glass 29 and the tip protruding from the document table glass 29 by a predetermined height. . In this state, the entanglement prevention portion 120f at the tip of the scale is set on the platen glass 2
It is held below the upper surface of 9. Therefore, the original placed on the original table glass 29 is accurately positioned by applying one end thereof to the scale front end surface 120c. Further, since the scale projection amount from the upper surface of the document table glass to the upper side is regulated by engaging the regulation means provided on the scale with the document table glass, the projection amount is always constant. Therefore, when the user sets the document at the exposure position on the platen glass by opening the automatic document feeder, one end of the document can surely be applied to the scale to regulate the document end.

When the ADF 60 is closed with respect to the main body 1 of the copying machine, the projecting portion 99a of the frame 99 supporting the rollers 96, 97 and the conveyor belt 95 is in contact with the scale 120, and the scale 120 has its leading end portion. Conveyor belt 9
5 and is kept in a state of protruding by a predetermined height from the upper surface of the platen glass 29. At this time, the scale 120 is shown in FIG.
It is set to drop slightly from the state of. The frame 99 is kept parallel to the original table glass 29 by a positioning member (not shown). Therefore, the copying machine body 1
When the ADF 60 is attached to, the positional relationship between the tip of the scale 120 and the conveyor belt 95 supported by the frame 99, and the contact state between the both can be easily and reliably maintained in an appropriate state. As a result, the rotation adjustment of the scale 120 becomes unnecessary, and the original does not pass uncontrolled by the scale 120 due to the insufficient pressure contact force or the amount of pressure contact, and the original can be reliably regulated by the scale 120.
Further, the accuracy of stopping the original when the front end of the original is brought into contact with the scale 120 is improved, and skew (diagonal feed) can be reliably corrected.

A lever 124 for rotating the scale 120
Is composed of two lever members 124a and 124b (see FIG. 4).
The connecting portion of is rotatably supported by a pin 125 fixed to the inner frame 2a of the ADF 60. Lever member 12
As shown in FIGS. 5 and 6, the pin connecting portions 4a and 124b have a fan-shaped portion 124 having a cross section centered on the fixing pin 125.
a ', 124b' are formed, and these are fixed pins 125
And the one lever member 124a (124b) is relatively inclined with respect to the other lever member 124b (124a) about the fixed pin 125 by a predetermined angle (β).
It can be rotated. Sectional fan-shaped part 124a ', 1
A stroke absorbing spring 127 is wound around 24b ', and both ends thereof are respectively lever members 124a,
124b, one lever member 124a is biased in the clockwise direction relative to the other lever member 124b, and is regulated to the state of FIG. 9. In the normal state, the lever members 124a, 124b is such that the upper surface intersection angle forms an angle φ (see FIG. 3). In addition, the long hole 124c provided in the lever member 124b has the pin SL1b.
Is connected to the plunger SL1a of the solenoid SL1 provided above. Plunger SL1a is A
The spring 126 provided on the inner frame 2a of the DF60
Is urged upward by. The biasing force of the spring 126 is adjusted so that the lever member 124a abuts the scale 120 when the solenoid SL1 is in the OFF state, but the scale 120 is not pushed down. That is, assuming that the urging forces of the springs 126, 123, 127 are N1, N2, N3, the respective urging forces are adjusted so as to satisfy the relationship of N3>N2> N1. Therefore, even if there is an error in mounting the ADF 60 to the copying machine body 1, the lever 124 can be securely attached to the scale 120.
Since the solenoid SL1 is turned on and the scale 120 is pushed down by the lever 124, the collision noise between the lever 124 and the scale 120 does not occur, and the solenoid SL1 is turned off to cause the scale 120 to move. The sound that collides with the rising restriction member (belt 95 or protrusion 99a) can also be absorbed.

In the scale pressing mechanism having the above structure,
When the solenoid SL1 is switched to the ON state, the lever 124 rotates clockwise, and as shown in FIG.
The tip of the lever member 124a presses the scale 120. The scale 120 rotates about a support shaft 122 as a fulcrum,
The scale lowering positioning projection 120a contacts the upper frame 2 of the copying machine body, and the leading end of the scale 120 stops at a position slightly lower than the original glass 29. This time,
The drive stroke of the solenoid SL1 is extra-that is, the plunger SL1a has not been completely sucked. The stroke excess amount δ is determined in consideration of the combination accuracy of the copying machine main body 1 and the ADF 60, etc., and is always greater than zero. Until this point, the spring 123
Since the biasing force of the spring 127 is larger than the biasing force N2 of the above, the upper surface intersecting angle between the levers 124a and 124b remains φ.

When the plunger SL1a is further attracted from this state, the attraction force N of the solenoid SL1 at this time is increased.
Since 4 is larger than the urging force of the spring 127, as shown in FIG. 8, the lever member 124a abutted on the scale 120 and regulated in position is opposed to the other lever member 124b.
Rotates in the clockwise direction, absorbs the excess stroke amount δ of the plunger SL1a, and the upper surface intersecting angle between the lever members 124a and 124b is φ in the final suction state of the plunger SL1a.
-Α (α <β), the relative angle between the lever 124a and the lever 124b is in the state shown in FIG. Therefore, the plunger SL1a is completely sucked in the ON state-that is, the plunger SL1a is not held in the incomplete suction state, so that the load in the ON state is low and the current consumption is minimized.

<Second Embodiment of Scale Pressing Mechanism> FIG. 9 shows another embodiment of the mechanism for pressing the scale 120. In this embodiment, the scale 120 is biased upward by a spring 123 to be squeezed. And 95, and the position is regulated in a state in which the front end surface of the original table glass 29 projects from the upper surface. The lever 124 is disposed inside the ADF 60, is rotatably held about a support shaft 125 as a fulcrum, and has a solenoid S at its substantially central portion via a stroke absorbing spring 127.
It is connected to the plunger SL1a of L1. With the solenoid SL1 off, the lever 124 and the plunger SL
The tip of the lever 124 abuts the scale 120 due to the moment due to the weight of the la 1a, but the scale 120 is adjusted so as not to be pushed down. In this mechanism, when the solenoid SL1 is switched to the ON state, the plunger SL1a descends and the lever 124 rotates clockwise around the support shaft 125, and the scale descending positioning protrusion 12
0a comes into contact with the upper surface frame 2, and the leading end of the scale is slightly lower than the original table glass 29, so that the positioning is performed. At this point, the plunger SL1a is not completely sucked. However, the amount of movement of the plunger SL1a thereafter is absorbed by the extension and deformation of the stroke absorbing spring 127.

<< Third Embodiment of Scale Pressing Mechanism >> FIG.
Shows another embodiment of the scale pressing mechanism. In this embodiment, the scale 120 is urged upward by the spring 123, abuts against the belt 95, and the leading end surface of the scale 120 is projected from the upper surface of the original table glass 29. The position is restricted. The lever 124 has a support shaft 125 at one end, which is a rib 611 fixed to the inner frame 610 of the ADF 60.
Is engaged with an elongated hole 612 extending vertically. The lever 124 is connected to a spring 127 having one end fixed to the inner frame 610 and is biased upward. The substantially central portion of the lever 124 is the plunger S of the solenoid SL1.
Although L1a is connected and the free end of the lever 124 contacts the scale 120 when the solenoid SL1 is off,
The scale 120 is not pushed down. In this mechanism, when the solenoid SL1 is switched to the ON state, the lever 12 moves as the plunger SL1a descends.
4 rotates clockwise and pushes down the scale 120. The scale 120 includes the scale descending positioning protrusion 12
0 a is in contact with the upper surface frame 2 and stops. At this point of time, the stroke of the solenoid SL1 is excessive, and the movement of the plunger SL1a after that is the spring 1
The extension of 27 and the downward movement of the long hole 612 of the support shaft 125 are absorbed. Further, irrespective of the embodiment described above, the driving source may be a rotary solenoid or a motor, and the driving force transmitting means may be composed of a material or shape having flexibility itself, or may use frictional force or magnetic force. A torque limiter type absorption mechanism may be used.

Notch 1 provided at the tip of the scale 120
The operation of 20e will be described. In the ADF 60, as described above, a plurality of originals conveyed between the separation roller 75 and the separation pad 80 based on the paper feeding action of the pickup roller 65 are separated by the separation roller 75 and the separation pad 8 from each other.
It is separated one by one by the separation effect of 0. At this time, a slip occurs between the document that is separated and conveyed toward the platen glass 29 and the separation pad 80, and further, the separation pad 8
Since 0 is made of a material with a relatively high coefficient of friction,
Paper dust or shavings of a document image (especially, an image with poor printability or image fixing property such as a copy document or a pencil-written document) is generated on the document portion that comes into contact with the separating pad 80, and the shaving dust adheres to the document. , Or once attached to the loosening pad 80,
Adheres to the following document. Similarly, paper dust adheres when the separated document passes through the separation pad 80 based on the driving of the registration rollers 90. The paper dust or the like adhered to the original adheres to the original when the original contacts a portion having a high contact pressure or a large contact angle with the original such as the resin film 133 (see FIG. 2) or the tip of the scale 120. Paper dust is scraped off and stains the platen glass 29, or falls into the inside of the copying machine main body 1 through the gap between the platen glass 29 and the upper frame 2 of the main body to pollute the optical system and chargers and deteriorate the image quality. Invite. Therefore, in the copying machine according to the present embodiment, as shown in FIG. 11, the cutouts 1 are formed at the tip portions of the scale 120 and the resin film 133 at the portions located on the extension of the separation roller 75 in the document transport direction.
20e and 133a are formed. Therefore, the paper dust on the original attached to the contact portion with the separating pad 80 is not scraped off by the resin film 133 or the scale 120, and the above-mentioned problem is solved. The AD of this embodiment is
In F, a movable scale is used, but the same applies to a fixed scale. Further, although the separating method uses the separating pad, various kinds such as a reverse roller type may be used. Further, if paper dust or the like is generated at the last roller or the reverse rotation roller portion, a notch may be provided at a portion corresponding to the position. On the other hand, the configuration of the ADF may be such that the transport unit on the platen glass is not limited to the belt but may be a roller or the like, and the same effect can be obtained in the configuration in which copying is performed while passing the fixed image reading unit at a constant speed. To be

<< Document Feeding Unit >> The document feeding unit 601 will be described. In FIG. 12, the document guide plate 131 is installed at a position slightly lower than the top of the pickup roller 65 and the separation roller 75 from the tip of the tray 61, and the tip thereof extends to the registration roller 90. The other document guide plate 132 is installed from above the separation roller 75 to the downstream side of the registration roller 90. The tip regulation plate 63 is fixed to the support shaft 64 while being fixed to the guide plate 13.
1, which is installed on the lower side of the guide plate 131, and is movable between a restricting position (a position shown in the figure) in which the tip of the guide plate 131 protrudes from the guide plate 131 and a retracted position retracted below the guide plate 131. Normally, the leading edge regulating plate 63 is set at the regulating position and has a function of receiving the leading edge of the document set on the tray 61 to give the operator a feeling of setting and align the leading edge of the document.
When the document feed start signal is issued, the leading edge regulation plate 63 is retracted below the guide plate 131 and is held at this retracted position until the final document is fed.

The original pressing plate 70 is a pickup roller 65.
As shown in FIG. 13, a plurality of guide sleeves 70b provided on the original pressing plate 70 are
It is inserted into a guide pin 74 fixed to a guide plate 134 so that it can be moved up and down and can be brought into and out of contact with a pickup roller 65. The document pressing plate 70 has the other end of a tension coil spring 73 whose one end is connected to both ends thereof. Each of them is connected to the guide plate 134 and is constantly urged upward. Lever 7
As shown in FIG. 14, 2 is fixed to a support shaft 71 and is rotatable about the support shaft 71 as a fulcrum. The support shaft 71 can be reciprocally rotated by the rotation driving means shown in FIG. 18, and the lever 72 is normally displaced to the solid line position, but is urged to rotate counterclockwise in the paper feeding operation. The document pressing plate 70 is urged toward the pickup roller 65, and the document to be fed is pressed against the pickup roller 65 with a predetermined pressure. The document pressing plate 70 has a number of documents,
The pickup roller 65 is moved in parallel with and perpendicular to the pickup roller 65 in order to achieve a reliable separation action with a constant document entry angle with respect to the front separation plate 85 and the separation roller 75 regardless of the thickness. Further, the document pressing plate 70
As shown in FIG. 13, the guide sleeve 70b and the guide pin 74 are fitted together with a gap, and the pressing surface 72a of the lever 72 is a spherical surface, and this spherical surface contacts the back surface of the document pressing plate 70. By doing so, the two paper feed rollers 65 can be brought into parallel contact with each other and pressure can be evenly applied, thereby preventing the skew of the document.

By the way, the frictional force μ1 between the separating roller 75 and the original, the frictional force μ2 between the separating pad 80 and the original, and the mutual frictional force μ3 between the originals are set so that μ1>μ2> μ3. As a result, of the two or three originals that have been "fed" by the pickup roller 65, one of the lowest layers
The sheet passes between the separating roller 75 and the separating pad 80.

Further, in order to improve the loosening performance, as shown in FIG. 12, a front loosening plate 85 and an elastic sheet 86 attached to the front loosening plate 85 are installed immediately before the loosening pad 80. The front separating plate 85 is provided in a downward slope from above the leading end regulating plate 63 in the sheet feeding direction, and the lower end thereof is close to the surface of the separating roller 75 immediately before the separating pad 80 with a slight gap. The lower end of the elastic sheet 86 is close to the surface of the separating roller 75 with a slight gap. The leading ends of the plurality of originals fed by the pickup roller 65 come into contact with the front separating plate 85, where the lower originals are advanced,
Only one or two originals pass through the lower end of the front separating plate 85. The elastic sheet 86 assists the front separating action of the front separating plate 85. Note that, in FIG. 12, reference numeral 132a denotes a document which is conveyed between the guide plates 131 and 132 by the sensor SE.
2, SE10 is a detection hole for detection.

<< Driving Mechanism of Tip Regulation Plate 63 and Pressing Plate 70 >> The driving mechanism of the tip regulation plate 63 and the pressing plate 70 will be described. In FIG. 14, a lever 140 is integrally fixed to an end of a support shaft 64 to which a tip regulating plate 63 is fixed, and a torsion spring 141 constantly urges it in a counterclockwise direction. By this urging force, the tip regulation plate 63
Is set to a regulation position protruding from the guide plate 131. Support shaft 71 to which holder 72 of pressing plate 70 is fixed
The lever 142 is integrally fixed to the end portion of the shaft, and is constantly urged in the counterclockwise direction by the torsion spring 143. The urging force causes the pressing plate 70 to elastically press the document on the pickup roller 65.

Fan-shaped cam plates 145, 146 are installed between the levers 140, 142. The cam plates 145, 1
A spindle 147 of 46 is connected to a pickup motor M1 capable of rotating in the forward and reverse directions. The lever 140 faces the outer peripheral surface of the cam plate 145, and the lever 142 faces the outer peripheral surface of the cam plate 146. The levers 140 and 142 rotate based on the forward / reverse rotation of the cam plates 145 and 146, and the tip regulating plate 6
3 and the position of the pressing plate 70 are set. Discs 148 and 149 are fixed to the cam shaft 147.
8, 149 notch edges 148a, 148b, 14
9a and 149b are transmissive photosensors SE11 and SE
12 (light emitting element x, light receiving element y) passes through the optical axis. The rotation of the cam plates 145 and 146 is controlled by the ON / OFF operation of the photosensors SE11 and SE12.

Specifically, when the ADF 60 is in the standby state, the levers 140 and 142 and the cam plates 145 and 146 are at the positions (home positions) shown in FIG. 11, the tip regulating plate 63 is set to the regulating position, and the pressing plate 70 is It is set in the retracted position. After the power is turned on, the pickup motor M1 is driven in the reverse direction, and the cam plate 14 together with the cam shaft 147 is driven.
5, 146 and the disks 148, 149 are reversed in the clockwise direction. Immediately after the reverse rotation, the sensor SE11 detects the edge 148a of the disk 148 and turns it off, whereby the cam 145,
The home position of 146 is confirmed, and the pickup motor M1 is temporarily turned off. When a document replacement signal is subsequently issued, the pickup motor M1 is driven in the reverse direction, the cam plates 145, 146 rotate in the clockwise direction, and the sensor S
E12 detects the edge 149b of the disk 149 and turns off, which turns off the pickup motor M1.
It stops at the position shown in FIG. 17 with some overrun. At this time, the lever 142 separates from the large-diameter portion of the cam plate 146, rotates downward by the spring force of the torsion spring 143, and the lever 72 rotates, whereby the pressing plate 70 is rotated.
Moves vertically downward, presses the leading edge of the document against the pickup roller 65, and applies a sheet feeding pressure. Further, the lever 140 comes into contact with the large diameter portion of the cam plate 145, and the tip regulating plate 6
3 rotates downward and retracts below the guide plate 131.

In this state, the pickup roller 65 and the separating roller 75 are rotationally driven to feed the first original. When the leading edge of the fed document reaches the registration roller 90, the pickup motor M1 is driven in the reverse direction, the cam plates 145, 146 rotate in the clockwise direction, and the sensor SE
12 is turned on by the edge 149a of the disc 149, which turns off the pickup motor M1. At this time,
As shown in FIG. 16, the levers 140 and 142 hold the tip regulation plate 63 in a standby state, and the pressing plate 70 retreats upward to release the pressing force on the document.

For the second and subsequent originals, the pickup motor M1 is driven to rotate normally, the cam plates 145 and 146 rotate counterclockwise, and the sensor SE11 detects the edge 148b of the disk 148 to turn it off. As a result, the pickup motor M1 is turned off, but it stops at the position shown in FIG. 17 with some overrun. Then, similarly to the above, the pickup roller 65 and the separating roller 75 are driven to rotate,
The first and subsequent documents are fed. When the leading edge of the fed document reaches the registration roller 90, the pickup motor M1 is reversely driven and returns to the pressing release position shown in FIG.

As described above, the rotation angle is minimized by operating the pickup motor M1 both when pressing from the home position (FIGS. 15 to 17) and when pressing from the pressing release position (FIGS. 17 and 18). Can be Further, the pickup motor M1 is prevented from being displaced due to the overrun of the pickup motor M1 due to the difference in the rotation direction.
Disk 149 by sensor SE12 when is driven in reverse
The edge 149b of the disk 148 is slightly faster than the detection of the edge 148b of the disk 148 by the sensor SE11. Conversely, the detection of the edge 148b of the disk 148 by the sensor SE11 when driven in the normal direction is detected by the sensor SE12. The sensor position and the disc are designed so as to be slightly earlier than the detection of the edge 149b of the disc 149 by.

That is, in this embodiment, the drive mechanism for the tip regulating plate 63 and the pressing plate 70 is simplified by a single system, and since it is driven by the cam plates 145, 146, no noise is generated during driving. . Further, since the leading edge regulating plate 63 is held at the retracted position from the start to the end of the paper feeding operation, the leading edge of the document is not damaged and the document is not skewed. Further, the pressing plate 70 presses the original only while the leading end of the original is passing the separating roller 75, and then retracts upward, so that there is no possibility of a paper feed error such as a document feeding.

<< Registration Roller >> The registration roller 90 will be described. In FIG. 12, the registration roller 90
In the nip portion, the leading edge of the document fed by the rotation of the pickup roller 65 and the separating roller 75 is temporarily received at the nip portion, and the leading edge of the document is aligned at the nip portion to correct the skew of the document. A predetermined period of time has passed since the sensor SE2 detected the leading edge of the fed document, and the feeding motor M2
Is turned off, and the pickup roller 65 and the separating roller 75 are turned off.
Rotation is stopped. At this time, the leading end of the original comes into contact with the nip portion of the registration roller 90 and forms a slight loop.

After that, the registration roller 90 is rotationally driven by turning on the main motor M3 at the same timing as the copying operation in the copying machine main body 1, and sends the document to the entrance of the document table glass 29. As described above, in this embodiment, the pickup roller 65 and the separating roller 75 are separately driven by the sheet feeding motor M2, and the registration roller 90 is driven by the main motor M3 together with the conveyor belt 95. Also,
One-way clutches 67 and 77 are provided between the pickup roller 65 and its drive shaft 66, and between the separation roller 75 and its drive shaft 76, and the original is sent by the registration roller 90 even when the paper feed motor M2 is off. At that time, the pickup roller 65 and the separation roller 75 are allowed to rotate idly in the clockwise direction.

A drive mechanism for the registration roller 90 and the conveyor belt 95 will be described. As shown in FIG. 18, a timing belt 155 is stretched between an output pulley 150 provided on the output shaft of the main motor M3 and a pulley 153 rotatably supported by a support shaft fixed to a frame (not shown). ing. A timing belt 157 is stretched between a pulley 154 integrally formed with the pulley 153 and a pulley 156 fixed to the support shaft 91 of the registration roller 90. A gear 158 is fixed to the other end of the support shaft 91 of the registration roller 90, and the gear 15 is rotatably supported by a support shaft 160 fixed to a frame (not shown).
9, and the gear 159 is engaged with the gear 161 fixed to the support shaft 162 of the drive roller 96. As a result, when the main motor M3 rotates in the direction of the arrow, the registration roller 90 and the drive roller 96 rotate in the same direction,
The conveyor belt 95 moves in the direction of arrow d. Further, the main motor M3 can rotate in the forward and reverse directions, and in the 2-in-1 mode or the double-sided mode, the document can be temporarily conveyed in the direction opposite to the direction of the arrow d.

<< Registration Roller 90, Paper Feeding Roller 65,
And Arrangement of Separation Roller 75 >> The arrangement relationship of the registration roller 90, the paper feed roller 65, and the separation roller 75 will be described with reference to FIG. In the ADF 60 of this embodiment, the sheet passing reference PS is provided on the back side of the copying machine, that is, on the side opposite to the operating side. The registration roller 90 and the separating roller 75 are
The rollers are arranged symmetrically with respect to the roller arrangement reference RS. This is to prevent a skew from occurring due to a moment when a document held between the separating roller 75 and the separating pad 80 is pulled out by the registration roller 90. Further, the conveying force of the registration roller 90 is set to be considerably larger than the conveying force of the separating roller 75, and slippage of the document at the time of conveyance by the registration roller 90 is prevented. Further, in the direction orthogonal to the document conveying direction, the central registration roller 90 and the separation roller 75 are at a distance D1, and the registration rollers 90, 90 and the separation rollers 7 on both sides are separated.
5 are arranged at a distance D2. Therefore, dirt such as paper dust generated in the pick-up section and the separating section is not transferred to the registration roller 90.
The carrying force of 0 is kept constant, and since dirt is not attached to the registration roller 90, dirt is not transferred from the registration roller 90 to the original.

<< Mechanism for Opening / Closing the Original Feeding Path of the Original Feeding Unit >> In FIG. 20, one registration driving roller 90a constituting the registration roller 90 is fixed to the support shaft 91a. The support shaft 91a has bearing holes 173a and 173a provided in the main frame 173 of the ADF 60, and the bearing 17
It is rotatably supported via 4a and 174a and is drivingly connected to the main motor M3. Further, cams 171a and 172a are provided on the support shaft 91a. The other registration driven roller 90b forming the registration roller 90 is fixed to the support shaft 91b. The support shaft 91b is a support shaft 91.
The bearings 174b, 17 are arranged in the long hole-shaped bearing holes 173b, 173b provided in the main frame 173 in parallel with a.
It is rotatably supported by a support shaft 91a via 4b so as to be movable back and forth. Eccentric cams 171b and 172 are provided on the support shaft 91b.
b is rotatably provided, and a frame 174 for holding the opening / closing cover 604 of the document feeding section 601 is an eccentric cam 171.
A guide plate 135, which is fixed to b and guides the original that has passed through the registration rollers 90 onto the original table glass 29, is fixed to the eccentric cam 172b. The support shaft 91b is biased toward the support shaft 91a by a biasing means such as springs 174c and 174c.

A document feeding section 601 having such a configuration
Then, in a normal state where the cover 604 and the guide plate 135 are closed with respect to the ADF 60, as shown in FIG.
Registration driving roller 90a and registration driven roller 90b
Is pressed. At this time, the cams 171a and 172a are separated from the eccentric cams 171b and 172b, respectively,
The center interval between them is set to M1. From this state, for example, when the cover 604 is rotated in the direction of the arrow f in order to take out the original jammed in the sheet passing path from the separating section to the registration section, the eccentric cam 171b rotates and its outer peripheral portion contacts the cam 171a. Further, when the cover 604 is further rotated against the biasing force of the spring 174c from this contact state, as shown in FIG. 22, the support shafts 91a and 91b are rotated.
The center distance between the registration driving roller 90a and the registration driving roller 90a increases to M2 (> M1).
On the other hand, as shown in FIG. 23, when the guide plate 135 is rotated in the direction of the arrow g in order to take out the original jammed on the downstream side of the registration portion, the eccentric cam 172b rotates and its outer peripheral portion comes into contact with the cam 172a. The center interval between the support shafts 91a and 91b spreads to M3 (> M1) and the registration driven roller 9
0b separates from the registration driving roller 90a. In addition,
The rollers 90a and 90b are often made of an elastic member such as rubber or sponge on the outer periphery thereof. With such a roller, it is not necessary that the rollers 90a and 90b be completely separated from each other. It is sufficient if the pressure contact force between the two can be weakened to the extent that the original held between them can be pulled out without damage. As described above, in the document feeding unit 601, the resist driven roller 90b is biased to the resist driving roller 90a by the springs 174c and 174c, and the cover 904 and the guide plate 135 are provided on the support shaft 91a based on the opening operation. The cam 171a,
Eccentric cams 171b, 1 fixed to 172a and support shaft 91b
72b is engaged with each other to release the pressure contact of the registration roller 90. Therefore, the roller 90a
It is possible to uniformly and accurately set the pressure contact force of the shafts 90b and 90b in the axial direction, and to keep the pressure contact force properly regardless of the mounting accuracy of the cover 904 and the locking force. Although the registration driven roller is retracted in this embodiment, the registration driven roller may be retracted. Further, the reverse relationship between the driving and the driven is also applicable.

<< Cover Supporting Mechanism >> The cover 604 is rotatably supported by the frame 174 via a shaft 175, as shown in FIG. A guide plate 132 is fixed to the frame 174.
The cover 604 is urged in the counterclockwise direction by a spring 176 or an elastic member such as sponge. As a result, when the cover 604 is closed, the cover 604 is urged by the spring 174, and the document transport unit 6
05 is abutted and positioned. Therefore, the cover 6
Even if a document or the like is placed on 04 and an external force is applied, the separation pressure between the separation roller 75 and the separation pad 80 is not affected. Further, even when a force is applied to the cover 604 from the side, the movement of the cover 604 is absorbed by the spring 176 and does not affect the separation pressure. Therefore, a stable handling pressure can always be secured. Moreover, an excessive load is not applied to the drive motor of the separating roller 75.

<< ADF Document Transport Mode >> The document transport mode of the ADF 60 will be described. In this example,
In addition to the double-sided mode that has been used conventionally, there are four types of document transport modes, a pre-step mode, a 2-in-1 mode, and a count mode. Further, the document transported by the ADF 60 is accurately stopped at the exposure reference position SP. For this purpose, there are a scale mode suitable for normal paper and a pulse control mode suitable for thin paper, and the scale mode and the pulse control mode are selected by a document selection key provided on the operation panel. When the document is conveyed, the document is exposed at the exposure reference position S
The exposure position is set to P, the pre-step position is set to the intermediate position IP, and the advance position is set to the nip portion of the registration roller 90. Regarding the size of the original, when the size is not specified, the small size is A
4 horizontal feeds, large size is assumed to be A3 vertical feed.

The scale mode is a mode in which the leading edge of the original document conveyed by the conveyor belt 95 is brought into contact with the scale 120 and forcibly stopped. In this case, the scale solenoid SL1 is turned off. As a result, the tip of the scale 120 is projected onto the platen glass 29. Document D conveyed in the direction of arrow d by the conveyor belt 95.
Has its tip abutted against the scale 120 and the conveyance force of the conveyance belt 95 is set to be weaker than the buckling resistance of the document, so that a strip occurs between the document and the belt, and the reference position S
P will stop exactly.

In the pulse control mode, as will be described below, the registration roller 90 and the conveyor belt 95 are driven by a single main motor (stepping motor) M3 so that the two conveyor speeds are the same, and the original document is conveyed. Transport length L
This is a mode for accurately controlling (see FIG. 26). The document conveyance amount with respect to the drive pulse number of the main motor M3 is known in advance. Therefore, the stop position of the document is determined by driving the main motor M3 with the number of pulses corresponding to the length L of the document waiting immediately before the registration roller 90 to the reference position SP. During execution of this pulse control mode, the solenoid SL1 maintains the ON state, and the scale 120 holds the position retracted downward from the upper surface of the document glass 29.

Comparing the scale mode with the pulse control mode, the scale mode shows that the original is scaled 120.
It has an advantage that the stop position accuracy is high since it is stopped by hitting. However, when the document is thin, the buckling resistance of the document is small, and there is a problem that the front end is likely to be bent or a paper jam occurs. The pulse control mode has an advantage that troubles at the time of stop do not occur even with a thin original, but there is a problem that the stop position accuracy is not necessarily as high as that of the scale mode due to slip of the original and deviation of response of the driving mechanism.

In the pre-step mode, when the document size is half or less from the exposure reference position SP to the document advance position (the position where the leading edge of the document contacts the registration roller 90), as shown in FIG. The leading edge of the original document D1 is stopped by aligning its leading edge with the exposure reference position SP, and the leading edge of the next original document D2 is conveyed to a position where its leading edge matches the intermediate position IP. This is a mode in which the paper is fed in advance until the leading edge contacts the registration roller 90. When combined with the pulse control mode in the pre-step mode, the main motor M3 performs a pulse so as to convey the document by a distance corresponding to 1/2 of the distance L from the registration roller 90 to the reference position SP when the document is replaced. Only P02 is driven forward. That is, the first original document D1 set at the exposure reference position SP
The main motor M3 generates a pulse P each time the exposure of
The second original D2 is conveyed to the exposure reference position SP by the forward rotation of 02, and the third original waiting on the registration roller 90 is conveyed to the intermediate position IP.

On the other hand, when the pre-step mode is combined with the scale mode, when the document is replaced, as shown in FIG.
As shown in, the main motor M3 is (L / 2) + (α /
The pulse P is used to convey the original for a distance corresponding to 2).
Only 02 'is driven forward. α is an overrun amount for surely bringing the leading end of the document into contact with the scale 120. Therefore, the second document D2 is conveyed from the registration roller 90 by (L / 2) + (α / 2) at the intermediate position I.
Wait at P '. This second document D2 has an intermediate position I
From P ′ by the conveyor belt 95 (L / 2) + (α /
2) A moving amount of movement is given, but (L / 2)-(α /
When the sheet is conveyed by 2), the leading end comes into contact with the scale 120 and stops at the exposure reference position SP, and the conveying belt 95 slips on the original by the distance α.

By the way, in such a scale mode, the solenoid SL1 is normally turned off and the scale 12
Reference numeral 0 projects upward from the upper surface of the platen glass 29.
The solenoid SL1 is turned on immediately before the document passes through the exposure reference position SP, and retracts the scale 120 below the platen glass 29.

<Pre-step mode> FIGS. 26 to 35 show the document conveyance state in the pre-step mode. FIG. 27 shows a state in which the originals are set on the tray 61, and in this case 3
It is assumed that the small size originals D1, D2 and D3 are set. First, the tip regulation plate 63 retracts downward, and the pressing plate 70
Moves downward, and the pickup roller 65 and the separation roller 7
5 is rotationally driven, the first original D1 is fed, and the apparatus waits with the leading edge abutting the registration roller 90 (FIG. 2).
8). Next, the main motor M3 is driven to rotate forward by the pulse P02, and the document D1 is conveyed to the intermediate position IP (see FIG. 29). Next, the pickup roller 65 and the separating roller 75 are rotationally driven, and the second document D2 stands by at the registration roller 90 (see FIG. 30). Further, the main motor M3 is driven to rotate in the normal direction by the pulse P02, and the document D
1 is conveyed to the exposure reference position SP, and the document D2 is conveyed to the intermediate position IP (see FIG. 31). Here, in the copying machine main body 1, the feeding of copy paper and the exposure by the optical system 20 are performed as many times as the number of copies. Third document D during exposure
3 is fed in advance to the registration rollers 90 (see FIG. 32).
reference).

When the exposure of the document D1 is completed, the main motor M3 is driven in the normal direction by the pulse P02, and the discharge motor M4 is driven to rotate the reversing roller 100 and the discharge roller 110. The document D1 is now in the tray 11
5 and the document D2 is exposed at the exposure reference position SP.
The document D3 is conveyed to the intermediate position IP (see FIG. 33). Here, the document D2 is exposed, and when the exposure is completed, the main motor M3 is driven in the normal direction by the pulse P02, and the discharge motor M4 is also driven. Therefore, the document D2 is placed on the tray 1
Then, the document D3 is fed to the exposure reference position SP (see FIG. 34). After the exposure of the document D3 is completed, the main motor M3 and the discharge motor M4 are driven to discharge the document D3 onto the tray 115 (see FIG. 35).

By the way, in the present embodiment, the original fed in advance is fed to the platen glass 2 by the registration roller 90.
9 and the trailing edge of the original is the registration sensor S.
When it is detected by E2, the empty sensor SE1 is checked, and if the document remains on the tray 61, the first-out paper feeding is performed. If there is no document, the leading edge regulation plate 63 is returned to the upper regulation position.

Here, the positional relationship between the registration roller 90, the resin film 133 and the pre-step position IP will be described with reference to FIG. The conveyor belt 95 is driven by a driving roller 96, and the driving roller 96
Even if you stop the drive to and fix with the brake,
The driven roller 97 further advances due to the inertia of the driven roller 97 and the delay in transmission of the driving force of the belt 95, and then the relationship between the tension side and the slack side generated during driving tries to return to the original balanced position. The document on the glass 29 is moved by a small amount. In the copying machine of this embodiment, the document moves on the platen glass 29 upstream in the document transport direction.

Therefore, in the ADF 60 of this embodiment, since the resin film 133 is provided in the belt conveying portion, if the length of the document is dp and the distance from the nip of the registration roller SD to the tip of the resin film 138 is d1, then L / 2-
When d1≈dp, this pre-step position IP
The trailing edge of the original to be stopped at the position interferes with the resin film 133. Further, if a minute skew occurs during the conveyance of the resist, only a part of the trailing edge of the document interferes with the resin film 133, which further aggravates the skew state. Therefore, in the ADF 60 of this embodiment, the relationship of L / 2−d1 <dp is set, and the disturbance of the original stopped state due to the interference with the resin film 133 is eliminated. In addition, the conveyor belt 9
When the return amount of 5 is β, the same effect can be obtained even if L / 2−d1-β> dp. Further, in the scale mode, L / 2-α / 2-d1 <dp, L / 2-α /
Each length may be set so as to satisfy the relationship of 2-d1-β> dp. In this embodiment, the nip position of the registration roller 90 is set to the forward position, but it may be positioned by a sensor or the like or may be regulated by a stopper gate.

As described above, in the pre-step mode, since the document is step-fed in units of (L / 2), the document replacement time is short and the optical system 20 after the exposure is completed.
The originals can be exchanged within the time it returns to the home position, improving copy productivity. Moreover, the succeeding original document (third original document) is fed in advance until its leading edge comes into contact with the registration roller 90. This advance feeding is performed during the exposure of the original document, and contributes to the improvement of copy productivity.

Further, as shown in FIG. 18, the registration roller 90 and the conveyor belt 95 are combined into a single main motor M3.
Since the main motor M3 is driven as a stepping motor in a pulse manner without interposing a clutch, the number of pulses supplied to the motor M3 is controlled, so that the document sent from the registration roller 90 is accurately referenced. It can be transported / stopped to the position SP. The motor M3 need not be a stepping motor, but the same effect can be obtained by attaching an encoder to the rotary shaft and converting the number of revolutions into the number of pulses to control the on / off of the motor M3.

<< 2-in-1 Mode >> The 2-in-1 mode will be described. The 2-in-1 mode is a mode in which two originals are set as a set and arranged on the platen glass 29 to form an image on one copy sheet. 36 to 47 show the document conveyance state in the 2-in-1 mode. In FIG. 36, the document is in the tray 61.
In this case, it is assumed that four small size documents D1, D2, D3 and D4 have been set. First, the first original D1 is fed and stands by with its leading edge in contact with the registration roller 90 (see FIG. 37). Next, the main motor M3 is rotated in the normal direction, and the document D1 is fed onto the platen glass 29. When the rear end of the document D1 reaches the platen glass 29 (see FIG. 38), the main motor M3 is switched to the reverse rotation, and the document D1 is switched back in the direction opposite to the arrow d. As a result, the rear end of the document D1 enters below the guide plate 132 and the film 133 (see FIG. 39). The switchback amount corresponds to the same length as the trailing edge of the original reaches the nip portion of the registration roller 90. It should be noted that when the switchback is performed, the resin film 13 is provided so that the trailing edge of the document does not return to the registration roller 90 side.
Guided by 3. The feeding of the second document D2 is started a predetermined time after the trailing edge of the first document D1 is detected by the registration sensor SE2, and immediately after the switchback of the document D1 is completed, the leading edge of the document D2 is fed. Is the registration roller 9
It contacts 0 and stops (see FIG. 39).

Next, the main motor M3 is driven in the forward direction to convey the originals D1 and D2 on the platen glass 29, and the original D
The main motor M3 is turned off at the time when the tip of No. 1 reaches the exposure reference position SP. As a result, the originals D1 and D2 are arranged side by side on the platen glass 29 (see FIG. 40). The rotation of the main motor M3 is decelerated immediately before the document D1 reaches the exposure reference position SP. The feeding of the third document D3 is started in synchronization with the timing of this deceleration. Then, by the time the exposure of the originals D1 and D2 is completed, the leading edge of the original D3 comes into contact with the registration roller 90, and the first-out paper feeding is completed (see FIG. 41).

When the exposure of the originals D1 and D2 is completed, the main motor M3 is driven in the normal direction and the discharge motor M4 is driven. The document D1 is the reverse roller 100 and the discharge roller 1.
10 is sent to the tray 115, and the document D2 becomes the document D.
After the first, the third document D3 is the platen glass 29.
It is fed up (see FIG. 42). When the rear end of the document D3 reaches the platen glass 29, the main motor M3 is switched to the reverse rotation, and the document D3 is switched back like the document D1. At this time, the document D1 is given a conveying force by the reversing roller 100, and is directly discharged onto the tray 115. The document D2 is switched back together with the document D3 because the leading edge of the document D2 has not yet reached the reversing roller 100 when the switchback is started (FIG. 43).
reference). The fourth original D4 is fed out to the registration rollers 90 immediately after the completion of the switchback.

The discharge motor M4 is driven as it is, and then the main motor M3 is normally driven. The main motor M3 is normally driven until the leading edge of the document D3 reaches the exposure reference position SP, whereby the documents D3 and D4 are juxtaposed on the platen glass 29 and the document D2 is discharged onto the tray 115 (see FIG. 44). ). The discharge motor M4 is turned off when the document D2 is discharged. In this way, the originals D1 and D2 are
The subsequent document D3 is once switched back in the middle of discharging, so that the interval is opened. When the two originals are pushed out onto the tray 115 without a gap, the succeeding originals stick out the preceding originals and the alignment on the tray 115 is disturbed, or the subsequent originals slip under the preceding originals and the page order is changed. Disturbed. However, as in this embodiment, the tray 115 is provided by opening the space between the two originals D1 and D2 at the time of ejection.
It is possible to eliminate the disorder of the original document.

When the exposure of the originals D3 and D4 is completed, the main motor M3 is driven to rotate normally and the discharge motor M4 is driven. The main motor M3 is once turned off when the rear end of the document D3 is separated from the conveyor belt 95 (FIG. 4).
5). When the main motor M3 is off,
The distance between the originals D3 and D4 corresponds to the time for opening the tray 115 to the extent that the tray 115 is not disturbed (see FIG. 46).
Here, the main motor M3 is driven to rotate normally, and the document D4 is discharged onto the tray 115 (see FIG. 47).

Ejection of the original document that has been exposed and setting of the subsequent original document at the exposure position SP are performed as described above. The reversing roller 100 and the discharging roller 110 are connected to the main motor M.
3 is driven by an independent discharge motor M4 different from 3,
Since the conveying force by the reversing roller 100 and the pinch roller 101 is set to be larger than the conveying force by the conveying belt 95, the document introduced into the discharge portion is conveyed by the conveying belt 9
5 can be discharged onto the discharge tray 115 regardless of the operating state. The switchback point BP (see FIG. 26) is constant regardless of the length of the document.

However, when the document size is dp, the distance from the nip portion of the registration roller 90 to the leading end of the film 133 is d1, the distance from the leading end of the film 133 to the switchback point BP is d2, and the pinch roller 1 is used.
If the distance from 01 to the exposure reference SP is d3, d3
If the positional relationship is such that> d1 + d2 (= d4) (see FIG. 26) is satisfied, the second sheet of the preceding document reaches the reverse roller 100 and the pinch roller when the trailing edge of the following document reaches the switchback point BP. After reaching 101, the preceding two originals are continuously discharged without a gap. When the leading edge and the trailing edge of two originals are overlapped with each other in this discharging process, the two sheets of paper are placed below the first discharged original on the discharge tray 115.
The first original slips in or pushes out the preceding original, disturbing the original alignment. The same problem occurs when the preceding document (especially the first sheet) has a short size and the succeeding (third sheet) document has a long size. At this time, the difference in the document length Δdp (copier .DELTA.dp = d, where dpmax is the maximum document length in the document transport direction and dpmin is the minimum document length in the document transport direction for which the 2-in-1 mode can be executed.
pmax-dpmin), d3> d4 + Δd
The positional relationship is set to satisfy p: (d4 = d1 + d2). As a result, the two originals that are exposed at the same time are ejected from the original table glass 29 with a sufficient space between them, and the arrangement order of these two originals is not disturbed.

<< Double Sided Mode >> The basic operation of the double sided mode will be described. As shown in FIG. 48, when the documents D1 and D2 are set on the document tray 61 and the copy start button of the copying machine body 1 is turned on, the ADF 60 starts the document feeding operation. When the document is fed, the pressing plate 70 presses the leading end of the document D1. Then, the document D1 is conveyed to the position of the registration roller 90 based on the rotations of the pickup roller 65 and the paper feed roller 75, and the leading end of the document is registered to the registration roller 90.
The pickup roller 65 and the paper feed roller 75 stop rotating at the point of time when they abut on to form a loop (see FIG. 49). Further, the pressing state of the document D1 by the pressing plate 70 is released, and the operation of feeding the first document is completed.

Next, the registration roller 90 and the conveyor belt 9
5, the reversing roller 100 is rotated, and the document D1 is conveyed onto the document table glass 29. Further, the scale solenoid SL1 is turned on to retract the leading end of the scale 120 to below the document table glass 29, and the switching claw 103 operates to switch the sheet feeding path of the document discharging section to the reverse path. When the exposure is completed, the document D1 is sent to the reversing path of the ejecting unit, and the registration roller 90, the conveyor belt 95, and the reversing roller 10 are held with the leading end held by the second driven roller 102.
0 pauses (see FIG. 50).

After a predetermined time, the reversing roller 100 rotates again, the conveyor belt 95 reversely rotates, and the conveyance of the document D1 is restarted. As a result, the document D1 passes through the reversing path and is sent again onto the document table glass 29, set at the exposure position SP, and the back side of the document is copied (see FIG. 51). When the copying of the back side of the document is completed, the document D1 is conveyed again to the reverse path, and the front side of the document is copied this time (see FIGS. 52 and 53). When the exposure operation on the surface of the original is completed, the registration roller 90, the conveyor belt 95, and the reversing roller 100 rotate, the switching claw 103 operates in the opposite direction, and the first original is ejected onto the paper ejection tray 115. (See Figure 54). When the first document is ejected, the switching claw 103 operates again, and 2
The document transport path is switched to the reverse path in order to reverse the first document (see FIG. 55). The second original is conveyed to the position of the registration roller 90 during the exposure of the surface of the first original (see FIG. 53), and the first original is placed on the original table glass 29.
Immediately after being discharged from the sheet, it is supplied to the exposure position SP on the platen glass 29 and processed in the same manner as the first original (see FIGS. 56 to 59).

<< Count Mode >> The count mode will be described. The count mode is a mode in which, before the copy process is started using the ADF 60, the document is cycled through the ADF 60 in advance without the copy operation and the number of documents is counted. If the number of originals is odd in 2-in-1 mode, ADF starts feeding from the last page
In 60, there is a problem that the image of the first page is formed on half of one copy sheet, that is, half of the cover of the copy is blank. Therefore, the ADF 60 counts the number of documents in advance, and if the number is an odd number, the last page document to be fed first is transported to the platen glass 29 only once, and the subsequent documents are transported in the 2-in-1 mode described above. I decided to. Further, since similar problems occur in double-sided copying and composite copying, it is necessary to count the number of documents in advance in the count mode.

Since the copy operation is not involved in the count mode, it is preferable to process as fast as possible (short time). However, in the ADF 60, since the front end of the document is stopped at the reference position SP on the downstream side of the platen glass 29 in the transport direction, when the document is stopped at the reference position SP even in the count mode, the distance between the document and the document is increased. Will be larger, and more time will be spent idling.

Therefore, in the count mode, the trailing edge of the original is placed at the stop reference position X on the platen glass 29 (see FIG. 2).
The document is temporarily stopped on the basis of the time point when the document reaches (see 5). As a result, the distance between the originals during execution of the count mode becomes the length from the stop reference position X to the nip portion of the registration roller 90, and the processing time is greatly reduced. The arrival of the trailing edge of the document at the reference position X can be detected by detecting the trailing edge of the document by the registration sensor SE2 and then counting the number of pulses for driving the main motor M3.

Note that the reference position X here is not limited to the position shown in FIG. 25, but can be set arbitrarily, and if it is on the upstream side of the stop reference position SP during the copying operation, the processing time of the count mode is Contributes to shortening. Further, the reference position X does not need to be set on the platen glass 29, and may be on the downstream side of the nip portion of the registration roller 90. Reference position X
The processing time is shortened as the distance from the registration roller 90 approaches the nip portion.

Further, in the count mode, it is preferable that the ADF 60 conveys the document at a speed faster than the reference speed at which the document is conveyed during the copying process. Furthermore,
When performing not only the count mode but also the operation of the ADF 60 that delays the copy operation, that is, the operation that causes the reduction of the copy productivity of 100% described above, the document conveyance speed must be faster than the reference speed. Is preferred. The operation of delaying the copy operation means that when the double-sided original is reversed by the reversing roller 100, the first original to be fed is conveyed to the exposure reference position SP, and the last original to be fed from the original table glass 29. It is time to discharge to the tray 115.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an automatic document feeder (ADF) equipped with an automatic paper feeder according to the present invention and a copying machine main body.

FIG. 2 is a cross-sectional view showing the internal structure of an ADF.

FIG. 3 is a side view showing the first embodiment of the scale pressing mechanism, showing a state where the scale is raised.

FIG. 4 is a partial plan view of the scale pressing mechanism according to the first embodiment.

FIG. 5 is a sectional view of a lever member of the scale pressing mechanism according to the first embodiment.

FIG. 6 is a sectional view of a lever member of the scale pressing mechanism according to the first embodiment.

FIG. 7 is a side view of the scale pressing mechanism according to the first embodiment, showing a state where a solenoid in operation is pressing the scale.

FIG. 8 is a side view of the scale pressing mechanism according to the first embodiment, showing a state where the plunger of the solenoid is completely retracted.

FIG. 9 is a side view showing a second embodiment of the scale pressing mechanism.

FIG. 10 is a side view showing a third embodiment of the scale pressing mechanism.

FIG. 11 is an explanatory diagram of a planar positional relationship between the leading end of the scale, the notch of the film, and the separation roller.

FIG. 12 is a cross-sectional view of a document feeding unit in the ADF.

FIG. 13 is a front view showing a supporting state of a pressing plate in a document feeding section.

FIG. 14 is a perspective view showing a drive mechanism for a leading edge regulating plate and a pressing plate in the document feeding section.

FIG. 15 is an explanatory diagram showing a state in which the leading end regulating plate shown in FIG. 14 is in a regulating position and the pressing plate is in a non-pressing position.

FIG. 16 is an explanatory diagram showing a state in which the front end regulating plate shown in FIG. 14 is in a non-regulating position and the pressing plate is in a non-pressing position.

FIG. 17 is an explanatory diagram showing a state in which the leading end regulating plate shown in FIG. 14 is in a non-regulating position and the pressing plate is in a pressing position.

FIG. 18 is a perspective view showing a drive mechanism for a registration roller and a conveyor belt.

FIG. 19 is an explanatory diagram of a planar positional relationship between a registration roller and a separation roller.

FIG. 20 is a perspective view of a registration roller support mechanism and a paper passage opening / closing mechanism.

FIG. 21 is an explanatory diagram of a relationship between a registration roller and a cam in the paper passage opening / closing mechanism of FIG. 20.

22 is an operation explanatory view of the paper passage opening / closing mechanism of FIG. 20. FIG.

FIG. 23 is an operation explanatory view of the paper path opening / closing mechanism of FIG. 20.

FIG. 24 is a schematic explanatory diagram of a mechanism that supports a cover of a document feeding unit.

FIG. 25 is an explanatory diagram of document transportation by a stepping motor and shows a case where the document is stopped in the pulse control mode.

FIG. 26 is an explanatory diagram of document transportation by a stepping motor and shows a case where the document is stopped in the scale mode.

FIG. 27 is an explanatory diagram of document transportation in the pre-step mode.

28 is an explanatory diagram of document conveyance in the pre-step mode subsequent to FIG. 27.

FIG. 29 is an explanatory diagram of document conveyance in the pre-step mode subsequent to FIG. 28.

FIG. 30 is an explanatory diagram of document conveyance in a pre-step mode subsequent to FIG. 29.

FIG. 31 is an explanatory diagram of document conveyance in a pre-step mode subsequent to FIG. 30.

32 is an explanatory diagram of document conveyance in the pre-step mode subsequent to FIG. 31. FIG.

FIG. 33 is an explanatory diagram of document conveyance in a pre-step mode subsequent to FIG. 32.

34 is an explanatory diagram of document conveyance in the pre-step mode subsequent to FIG. 33. FIG.

FIG. 35 is an explanatory diagram of document conveyance in a pre-step mode subsequent to FIG. 34.

FIG. 36 is an explanatory diagram of document transportation in the 2-in-1 mode.

FIG. 37 is an explanatory diagram of document transportation in the 2-in-1 mode following FIG. 36.

FIG. 38 is an explanatory diagram of document conveyance in the 2-in-1 mode following FIG. 37.

FIG. 39 is an explanatory diagram of document conveyance in the 2-in-1 mode following FIG. 38.

FIG. 40 is an explanatory diagram of document conveyance in the 2-in-1 mode following FIG. 39.

FIG. 41 is an explanatory diagram of document conveyance in the 2-in-1 mode following FIG. 40.

FIG. 42 is an explanatory diagram of document conveyance in the 2-in-1 mode following FIG. 41.

FIG. 43 is an explanatory diagram of document conveyance in the 2-in-1 mode following FIG. 42.

FIG. 44 is an explanatory diagram of document transportation in the 2-in-1 mode following FIG. 43.

FIG. 45 is an explanatory diagram of document conveyance in the 2-in-1 mode following FIG. 44.

FIG. 46 is an explanatory diagram of document conveyance in the 2-in-1 mode following FIG. 45.

FIG. 47 is an explanatory diagram of document conveyance in the 2-in-1 mode following FIG. 46.

FIG. 48 is an explanatory diagram of document transportation in the duplex mode.

FIG. 49 is an explanatory diagram of document conveyance in the double-sided mode following FIG. 48.

FIG. 50 is an explanatory diagram of document conveyance in the double-sided mode following FIG. 49.

FIG. 51 is an explanatory diagram of document conveyance in the double-sided mode following FIG. 50.

FIG. 52 is an explanatory diagram of document conveyance in the double-sided mode following FIG. 51.

FIG. 53 is an explanatory view of document conveyance in the double-sided mode following FIG. 52.

FIG. 54 is an explanatory view of document conveyance in the double-sided mode following FIG. 53.

FIG. 55 is an explanatory diagram of document conveyance in the double-sided mode following FIG. 54.

FIG. 56 is an explanatory view of document conveyance in the double-sided mode following FIG. 55.

FIG. 57 is an explanatory diagram of document conveyance in the double-sided mode following FIG. 56.

FIG. 58 is an explanatory diagram of document conveyance in the double-sided mode following FIG. 57.

FIG. 59 is an explanatory diagram of document conveyance in the double-sided mode following FIG. 58.

FIG. 60 is a schematic side view of a conventional paper feeding mechanism.

FIG. 61 is a schematic side view of a conventional paper feeding mechanism.

[Explanation of symbols]

1 ... Copier, 60 ... Automatic Document Feeder (ADF), 29
... Platen glass, 120 ... Scale.

Claims (1)

[Claims] 1. A first roller, a second roller which cooperates with the first roller to apply a conveying force to a sheet, a first frame which supports the first roller, and the first roller. A second frame that supports two rollers and is rotatably supported by the first roller via the second roller, and the first roller or the second roller can move back and forth with respect to the other. Supporting means for supporting the first roller or the second roller, and a biasing means for biasing the first roller or the second roller toward the other roller; The roller and the second roller are pressed against each other,
A sheet feeding device, comprising: a switching unit configured to reduce a pressure contact force between the first roller and the second roller to switch the second frame from a sheet feeding state to a non-sheet feeding state.