JPH10316257A - Sheet carrying device and image forming device provided with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a sheet carrying device capable of preventing retransfer of part of a sheet image to the next sheet from contaminating it when a sheet having an image easy to be transferred is fed. SOLUTION: A paper feeding roller 5 abutting to stacked sheets is formed hollow having an air layer 503 along an outer circumference. An outer circumferential part of the paper feeding roller can thus the elastically deformed easily, and a contact surface with the sheet becomes large to make pressure to the sheet small, thereby part of an image of pencil powder or toner powder on the sheet being fed is prevented from being retransferred to the next sheet.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet conveying apparatus applicable to an image forming apparatus such as a copying machine and an LBP, and an image forming apparatus provided with the sheet conveying apparatus. The present invention relates to a sheet conveyance device including a separation device for separating and handling one sheet, placing the conveyance device at a predetermined position, and conveying the sheet, and a sheet feeding device.

[0002]

2. Description of the Related Art Conventionally, a sheet conveying apparatus is applied to an automatic document feeder for conveying and placing a document (sheet) on an image reading unit of an image forming apparatus such as a copying machine and automatically feeding the document. A plurality of documents stacked on the document tray
Each sheet is separated and fed to a predetermined position.

That is, the original transport device 3 shown in FIG.
As indicated by reference numeral 02, a plurality of sheets (documents) stacked on the document tray 304 are fed from the uppermost sheet to the separation unit side including the separation roller 308 and the separation belt 306 by the rotation of the feed roller 305. Separation roller 30 that rotates in the direction
8 and the separation belt 306 that rotates in the direction to return the sheets, and reliably feeds the sheets one by one.

The separated and fed sheet is fed to a first sheet feeding roller 3.
The sheet is fed at 16 and abuts against the stationary second sheet feeding roller 309, corrects the skew of the sheet due to the loop, aligns the leading ends, rotates the second sheet feeding roller 309, and feeds the sheet further downstream. . Further, the driving roller 336 that rewinds the transport belt 307 for transporting the sheet on the platen for reading the image of the sheet is driven to rotate, and the sheet is transported and mounted at a predetermined reading mounting position.

When the reading of the sheet image is completed, the conveying belt 307 is driven again to convey the sheet to the sheet discharge tray 310, and the sheet discharge tray 31 is driven by the sheet discharge rollers 311 and 312.
Discharge to 0.

[0006]

However, in the above-described conventional example, a plurality of sheets (original documents) stacked on the original tray 304 are fed from the uppermost sheet to the separation unit side including the separation roller 308 and the separation belt 306. Feed roller 30
5, a rubber member 351 is wound around a core member 352 generally formed of a resin member or the like as shown in FIG. 14, and a pressing force F acts on a sheet (document) P on a tray. By rotating in the clockwise direction, the uppermost sheet of the stacked sheets P is fed in the markless direction.

On the other hand, if the sheet (original) to be fed is an original written with a pencil or the like or a copy sheet output with toner that is easily peeled, the sheet feeding roller 305
Since in the region L ₀ in contact, pressure force F is acting, pencils and toner sheet back surface that is fed is, soiling and retransferred to the next sheet top waiting by pressure There was a defect.

According to the present invention, when a plurality of stacked sheets are fed by a feeding means, even if the sheets have an image which is easy to be transferred, the images are regenerated at the time of feeding the sheets. It is an object of the present invention to provide a sheet conveying device that prevents a sheet from being stained by transfer.

[0009]

The invention according to claim 1 is
In a sheet conveying apparatus having a stacking unit for stacking sheets, a feeding rotator that feeds out the sheets on the stacking unit, and a separating unit that separates the fed sheets one by one, the feeding rotator includes: It is characterized by having an air layer made of an elastic body along the outer periphery therein.

According to a second aspect of the present invention, the feeding rotating body comprises a core member and an elastic body provided around the core member to form an air layer, and the air layer is provided with an air hole communicating with the outside air. It is characterized by having.

The invention according to claim 3 is characterized in that the feed rotary body has a groove on the outer periphery that intersects the circumferential direction.

The invention according to a fourth aspect is characterized in that the sheet fed by the feed rotator is a sheet document having an image.

[Operation] Based on the above configuration, the sheets stacked on the stacking unit are sent out to the separation unit on the downstream side by the rotation of the feeding rotating body, and are separated and fed one by one. The feed rotator has a function of easily elastically deforming and expanding a contact area with a sheet by forming an air layer inside.

Further, since the groove is formed on the outer periphery of the feeding rotating body, paper powder and toner powder of the sheet are taken into the groove,
Has the effect of preventing adhesion to other sheets.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

<Description of Apparatus> In FIG. 1, an ADF (sheet conveying apparatus of the present invention) 2, which is an automatic document conveying apparatus,
A document tray (stacking means) 4 is provided above, and a wide belt 7 wound around a driving roller 36 and the other turn roller 37 is disposed below the document tray (stacking means). A sheet document (hereinafter, referred to as a document) P as a sheet on a document tray is sequentially separated from the uppermost sheet and transported to a platen glass (platen) 3 which is a reading position of the copying machine main body 1.

The wide belt 7 is in contact with the platen 3 and places the original P conveyed from the original tray 4 at a predetermined position on the platen 3 or discharges the original P on the platen 3. It is carried out onto the paper tray 10. Note that the original P is one page (two pages) and three pages (four pages) in order from the top.
Are placed on the tray 4 in this order.

The copier main body 1 includes an image input unit 200 (hereinafter referred to as a reader unit) and an image output unit 300 (hereinafter referred to as a printer unit).

The reader section 200 optically reads image information recorded on the document P, photoelectrically converts the read image information, and inputs it as image data.
Scanner unit 204 having mirror 203, mirrors 205 and 206, lens 207, image sensor 2
08 etc.

The printer unit 300 is a well-known image forming unit and has a configuration shown in FIG.

In FIG. 1, recording sheets in cassettes 100 and 102 are conveyed to registration rollers 106 by paper feed rollers 101 and 103. Reference numeral 104 denotes a manual feed tray.
6 is fed. The sheet on the sheet feeding table 108 a of the sheet feeding deck 108 is fed by a sheet feeding roller 109, and is conveyed to a registration roller 106 by a conveying roller 110.
The photosensitive drum (image forming unit) 112 includes an image input unit 2
From 00, a toner image is formed by image information. 114
Is a developing roller, 115 is a transfer charger, 116 is a separation charger, 117 is a transport unit that transports a sheet on which an image has been formed by the photosensitive drum 112, 118 is a fixing unit, and 119 is a transport roller.

The sheet after fixing is guided by a flapper 120 for one-sided copying, discharged to a sorter by discharge rollers 121, and a non-sort tray 122 for non-sorting.
a. In the case of sorting, a discharge sheet is discharged to a plurality of trays 122b by discharge rollers 122d.

In the case of double-sided copying or multiple copying, the sheet after fixing is branched by the flapper 120 and is conveyed by the conveying roller 2.
01 and the belts 202 and 2 in the case of double-sided copying.
The sheet is discharged to the intermediate tray 200 via the path 04, the path 206, and the discharge roller 205. In the case of multiple copying, the sheet is discharged to the intermediate tray 200 by the flapper 203. 2
09 and 210 are half-moon rollers for feeding the sheet, 211 is a pair of separation rollers, and 213, 214 and 2150 are conveying rollers for conveying the sheet to the registration roller 106.

The present invention is also applicable to a reader in which the reader unit 200 and the document feeder are integrated. Further, the copying machine main body 1 may include a document conveying device.

<Description of Configuration of Document Tray> A pair of width direction regulating plates are slidably disposed in the document tray 4 in the width direction of the document P, and the document P
Is regulated in the width direction to ensure the stability of the document P during feeding.

A rotating stopper 21 is provided at the end of the document tray 4 so that the document P set on the document tray 4 is restricted by the protruding stopper 21 so that it cannot advance downstream. (Fig. 4).

<Description of Sensor on Tray> Stopper 21
A document set detection sensor 40, which is a transmission-type optical sensor for detecting that the document bundle P has been set,
a and 40b are provided (FIG. 4).

Further, in the middle of the document tray 4, there is provided a document trailing edge detection sensor 41 which is a reflection type optical sensor for determining whether or not the set document is a half size document. This sensor is located at a distance of 225 mm from the stopper 21. When a longitudinal document is set, the rear end detection sensor 41 is turned on.

A final document detection sensor 43, which is a reflection type optical sensor, is provided between the document set detection sensor 40 and the rear end detection sensor 41, and determines whether the document being transported is the last document. I can do it.

Further, a paper width detecting sensor 44 for detecting the length in the width direction of the document bundle P set on the document tray 4 by detecting the position of the width direction regulating plate is provided below the document tray 4. I have.

<Description of Separation Section> Above the document tray 4, as shown in FIG. 5, a swing arm 53 is provided with a lift arm 51 which swings with respect to the rotation width center c 1 of the separation conveyance roller 8.
The swing arm 53 is swing-restricted by an arm shaft 51c that is supported by the front and rear support plates 51a and 51b, and a feed roller (feed rotating body) 5 is provided at the tip of the swing arm 53.

Normally, as shown in FIG. 5, which is the home position, the paper feed roller 5 is restrained by the shaft 51c and retracts above the upper separating guide plate 52 (suppressed by the pin 51g). The position is set so that the document setting work is not hindered. The arm 51 is, as described later,
It is controlled by the swing motor 103 (FIG. 12) and is at the position shown in the figure.

Separating means is constituted by a separating and conveying roller 8 rotating in the feeding direction of the original P and a separating belt 6 rotating in the returning direction of the original P and separating the originals P one by one.

FIG. 9 is a plan view of a separation structure according to the present invention.

The elevating arm 51 rotates about the center C1 of the rotating shaft, and is movable from the position shown in FIG. 5 to the position shown in FIG.
As described above, the paper feed roller 5 is provided at the tip of the swing arms 57 and 53 that rotate around the rotation center axis C1. The swing arms 57 and 53 descend by their own weight with the movement of the lifting arm 51, and the paper feed roller 5 lands on the uppermost sheet of the document P and stops (the position in FIG. 8). By rotating the paper feed roller 5 in this state, the original can be sequentially conveyed from the uppermost sheet. The upper guide plate 52 is suppressed to the position shown in FIG. 6 by a stopper (not shown).

In the state shown in FIG. 8, the swing arms 57, 5
The arm shaft 51c supporting the arm 3 is disengaged when the paper feed roller 5 lands on the sheet surface. At this time,
The relative positional relationship between the swing arms 57 and 53 and the lifting arm 51 starts to shift. The amount of this displacement is equal to the first swing arm flag 5 which is a part of the swing arms 57 and 53.
4. Second swing arm flag 55 and lifting arm 5
By the first swing position sensor 46 and the second swing position sensor 47 attached to 1, the non-detection state is changed to the detection state as shown in FIG. 8, so that the swing arm is controlled to stop.

In this state, the swing arms 57 and 53 and the paper feed roller 5 are placed on the original bundle P loaded on the tray 4 by their own weight, and a stable feeding force is always applied to the original P. It is possible to give.

The elevating arm 51 is driven by a seeding motor 103 (stepping motor), and the elevating arm 51 can take an arbitrary position (position in FIG. 7) between FIGS. .

Above the separation section, a paper feed roller home sensor 45, which is a transmission type optical sensor, is attached to a fixed support plate 56, and a lift arm flag 51d provided on swing arms 57 and 53 feeds paper. When the sensor optical path of the roller home sensor 45 is blocked, it is detected that the elevating arm 51 is at the standby position, which is the home position.

As described above, the first swing position sensor 46 which moves integrally with the lifting arm 51 and the second
A swing sensor 47 is provided, and swing arms 53 and 5 are provided.
The first swing arm flag 54 and the second swing arm flag 55 formed extending in the descending direction of No. 7 can be detected.

The state shown in FIG. 7 described above is a retreat position during continuous sheet feeding, and the swing arms 57 and 53 do not need to return to the home position (the state shown in FIG. 5). It is controlled so that it stops intermediately at a position separated by a minimum amount (about 3 to 5 mm).

The plurality of feed rollers 5 arranged in the width direction as shown in FIG. 9 each have an independent suspension structure, and are easily equalized to the sheet bundle of originals P, so that the sheet feeding performance is improved. It is possible to measure

As shown in FIG. 10, the paper feed roller 5 is formed such that a rubber member (elastic body) 501 is wrapped around a core member 502 made of resin or the like to support the rotation axis of the roller. ing. The rubber member 501 is formed of a rubber material having a high frictional force since the paper is gripped by the frictional force.

The paper feed roller 5 is formed in a hollow shape so that the inside of the rubber member 501 becomes the air layer 503, and maintains the shape expanded by the elasticity of the rubber member 501 itself. Therefore, as shown in FIG. 11, when a pressing force due to the weight of the roller is applied when feeding the document P, the document P can be easily elastically deformed, and the contact surface L between the document P and the roller can be increased.

A knurled groove 505 is continuously formed on the outer periphery of the rubber member 501, and paper powder and toner powder generated by friction when paper is fed are taken into the groove 505. It prevents paper powder and toner powder from adhering to the rubber surface that comes in contact with the paper, thereby preventing a reduction in frictional force.

An air hole 504 is formed in the core member 504 for connecting the air layer 503 of the rubber member 501 to the outside air, so that when the roller is elastically deformed, the air easily escapes or when the roller expands due to its own elasticity. Air enters.

By configuring the paper feed roller 5 in such a configuration, the roller is easily deformed, and the contact surface L between the original P and the roller can be increased to about two to four times that of the conventional roller. Pressure can be reduced from 1/2 to 1
For example, when the sheet (original) to be fed is an original written with a pencil or the like or a copy sheet output with toner that is easily peeled, an area where the feed roller 5 contacts the original P Since the pressing force F acts on L, it is possible to prevent the pencil and toner on the back surface of the fed sheet from being retransferred to the next upper surface of the waiting sheet by pressure.

Downstream of the shutter 21 in the transporting direction, a separating section including a well-known separating belt 6 and a separating and transporting roller 8 is provided, and performs a separating operation by rotating in the direction of an arrow (FIG. 8).

<Explanation of Conveying Path> As shown in FIG. 3, a document feeding path (a), (b), and (c) is formed from the document tray 4 to the platen 3, and this document feeding path ( (B) (b) and (c) are bent (curved downward) and connected to the transport path (d) on the platen 3 to guide the document P onto the platen 3.

A reversing feed path (H), (F), and (RI) extend from the original feed path (B) so that the original can be turned upside down before the original is conveyed to the platen 3. .

The original inverted in the reversing feeding path (h), (f), and (i) is switch-packed, conveyed to the platen 3 through the original feeding / discharging path (e), and placed thereon.

Further, a document reversing path (g) is branched from the reversing feeding path (f) so that the document reversing path (g) can be joined with the document feeding path (b). Using (c), the document on the platen 3 is switched back, turned upside down, and can be returned to the platen 3 again.

After the reading of the image on the platen 3 is completed, the document is discharged to the discharge tray 10 through the document conveying path (d) on the platen and the document discharge path (nu) shown in FIG.

On the right side of the ADF 2, as shown in FIG.
An openable manual document tray 14 is provided so that the set document P (single document) can be fed to the platen 3 through a manual feed path.

<Description of Roller Arrangement> Document Conveying Path (A)
Is a conveyance path in which the document separated by the separation unit is conveyed downstream by the separation feeding roller 8.

A first feeding roller 16 is provided between the document feeding paths (a) and (b), and the document fed from the separation units 6 and 8 is restrained by the separation unit. Prevents skewed originals. Further, the separation / conveyance roller 8 is provided with a one-way mechanism to reduce the conveyance load when the original is pulled out of the separation unit by the first feeding roller 16.

A second feeding roller 9 is provided at the junction of the document feeding paths (a), (b) and (c) and the document reversing path (g). A loop is formed in the arrived document P to prevent the document P from being skewed.

A first reversing roller 17 and a second reversing roller 18 are provided in the reversing feeding path (H), (F), and (L), and convey the document P along a loop reversing path. .

On the right side of the ADF 2, a manual feed roller 1 is provided.
The document feeder 3 feeds a document set on the manual document tray 14 from right to left.

A manual feed registration roller 11 is provided between the manual feed roller 13 and the platen 3 to form a loop on a manually fed document and prevent skew.

Further, the manual registration rollers 11 relay the discharge of the original from the platen 3.

A discharge roller 12 is provided in the document discharge path (nu), and the discharged document P is discharged from the discharge tray 10.
To be discharged.

<Description of In-Path Flapper> FIG. 4 shows the position of the flapper on the transport path.

A reversing sheet flapper 22 is provided downstream of the second feeding roller 9 in the conveying direction, and switches between a document feeding path (C) and a reversing feeding path (H). When the original P is transported to the reverse feeding path (H), (F), and (U), the original P is located at the solid line position in the figure. When the original P is transported to the original feeding path (C) and (D), the figure is shown in the figure. Swing to the dashed line position.

A reversing flapper 23 is provided downstream of the second reversing roller 18 in the transport direction, and switches between a reversing feeding path (i) and a document reversing path (g).

When reversing the original P conveyed from the original feeding path (b) or the reverse feeding path (h), the reversing flapper 23 is located at the solid line position in the drawing and the original from the flatten 3 is In the case of reversing through the feeding / discharging path (e), the reversing feeding path (f), and the document reversing path (g), the swing is performed to the position indicated by the chain line in the figure.

A one-way flapper 24 (to which a mylar or the like is affixed) is provided at the junction of the reverse feeding path (h) and the document feeding / discharging path (e) near the upstream of the first reverse roller 17. And serves as a guide when the original P is transported from the reverse feeding path (h) to the reverse feeding path (f).
The original P is fed from the reverse feeding path (U) (F) to the original feeding / discharging path (E).
When the document P is conveyed to the platen 3, the document P is prevented from entering the reverse feeding path (h) backward.

A supply / discharge flapper 25 is provided on the side of the reversing supply / discharge path (e) that moves in conjunction with the reversal sheet supply flapper 22.
Is conveyed at the solid line position in the figure to prevent the leading end of the document P entering the platen 3 from colliding with the end of the platen 3. When the document P is conveyed from the platen 3 to the document supply / discharge path (e), the document P is swung to the position indicated by the dashed line in the figure so that the document from the platen 3 can be scooped.

A paper discharge flapper 26 is provided between the right end of the platen 3 and the manual feed registration roller 11, and when the original P is transported from the manual feed path (R) to the platen 3, it is at the position indicated by the solid line in FIG. This prevents the leading edge of the document P entering the platen 3 from colliding with the end of the platen 3.
When the document P is discharged from the platen 3 to the document discharge path (nu), the document P is swung to a dashed line position in the figure so that the document from the platen 3 can be scooped.

A one-way manual flapper 27 is provided at the confluence of the document discharge path (N) and the manual feed path (R), and is used when the document P is discharged from the platen 3. The document is prevented from entering the document.

A manual shutter 28 is provided near the downstream side of the manual paper feed roller 13 in the transport direction, and a manual document set on the manual document tray 14 during ejection of the copied document P enters the manual registration roller. To prevent At this time, the conveying force is set low so that the manual paper feed roller 13 and the document slip.

<Arrangement of Sensors in Path> A separation sensor 30, which is a transmission type optical sensor, is provided between the separation conveyance roller 8 and the first feeding roller 16, and the separation conveyance roller 8 conveys the separation sensor 30. The original P is detected. Also, the separation sensor 3
A skew detection sensor 31, which is also a transmission type optical sensor, is provided at the same position in the transport direction as 0 and at a predetermined distance in the thrust direction, and has been fed together with the separation sensor 30. The amount of skew of the document can be detected.

In the vicinity of the downstream of the first feeding roller 16, there is provided a mixed-load detecting sensor 32 for detecting the document P by moving the flag. It is possible to detect that a document is set on the document tray 4.

In the vicinity of the upstream of the second feed roller 9, a paper feed sensor 35, which is a transmission type optical sensor, is provided. The original feed path (a), (b), (c) and the original reversing path The front end and the rear end of the original P that has passed through any one of the transport paths (1) and (2) are detected.

A registration sensor 39, which is also a transmission type optical sensor, is provided downstream of the feed roller 9, and controls the stop position of the document P by detecting the rear end of the document P. .

A reversing sensor 50, which is a transmission type optical sensor, is provided in the reversing conveyance path (e), and detects the document P discharged from the platen 3 or the document P entering the platen 3. .

A reversal detection sensor 33 for detecting the document P by moving the flag is provided in the reversing feeding path (R), and the document P is guided to the reversing feeding path (R) by switching the reversing flapper. Has been detected.

A manual feed registration sensor 34, which is a transmission type optical sensor, is provided near the downstream of the manual feed registration roller 11 in the sheet discharging direction. Drainage route (nu)
The original P discharged to the printer is detected.

A manual document detection sensor 60 for detecting a document P by moving a flag is provided on the manual document tray 14 side of the manual paper feed roller 13, and detects that a document is set on the manual document tray 14.

<Description of Driving System> Next, the driving system of the document feeder 2 of the present invention will be described with reference to FIG.

FIG. 4 is a drive system diagram showing motors and solenoids for driving each transport roller and flapper.

Reference numeral 100 denotes a separation motor. In this embodiment, a DC brush motor controlled by PLL is used. A clock plate 100a composed of a plurality of slits is provided on the motor shaft of the separation motor 100,
When the separation motor 100 is rotated by the slit and the separation clock sensor 100b which is a transmission type optical sensor, a clock pulse proportional to the motor rotation speed is generated.

The separation motor 100 drives the separation / conveyance roller 8 and the separation belt 6, which are separation sections, in the direction of the arrow in the figure. Further, the drive is transmitted to the paper feed roller 5 via the separation clutch 106.

Reference numeral 101 denotes a transport motor capable of rotating forward and backward, and in this embodiment, a stepping motor is used. The transport motor 101 drives the second feeding roller 9, the first reversing roller 17, and the second reversing roller 18.

On the driven roller shaft of the second feeding roller 9,
A clock plate 101a including a plurality of slits is provided, and a clock pulse is generated when the transport motor 101 is rotated by the slit and an inverted clock sensor 101b which is a transmission type optical sensor. If a slip occurs while the document P is being conveyed by the second feeding roller 9, the slip amount can be measured from the number of clock pulses and the number of drive clocks of the conveyance motor 101.

Reference numeral 102 denotes a belt motor capable of transmitting power in the forward and reverse directions. In the present embodiment, a stepping motor is used. The belt motor 102 drives the driving roller 36 that drives the wide belt 7, and further transmits the rotation of the driving roller 36 to the turn roller 37 by the wide belt 7.

The drive is transmitted from the turn roller 37 to the manual registration roller 11. The conveying speed of the original on the platen 3 and the conveying speed of the manual registration roller 11 are made equal.

Reference numeral 103 denotes a reciprocating swing motor. In this embodiment, a stepping motor is used. The swing motor 103 drives a lifting arm 53 of a paper feed roller.

Reference numeral 104 denotes a paper discharge motor. In this embodiment, an FG servo control type DC motor is used. A clock plate 104a composed of a plurality of slits is provided on the motor shaft of the discharge motor 104. When the discharge motor 104 is rotated by the slit and the discharge clock sensor 104b, which is a transmission-type optical sensor, the motor is driven by the motor. A clock pulse is generated in proportion to the rotation speed.

The discharge motor 104 outputs the discharge rollers 12,
The drive is transmitted to the manual feed roller 13.

Reference numeral 105 denotes a stopper solenoid which drives the stopper 21 at the paper feed end of the document tray 4. When the stopper 21 is off, it is at the position indicated by the solid line in the figure, and when it is on, it swings to the position indicated by the chain line in the figure.

Reference numeral 106 denotes a separation clutch, which is a separation motor 1
00 is transmitted to the feed roller 5, the separation belt 6, and the separation / conveyance roller 8.

Reference numeral 107 denotes a path switching solenoid.
The reverse feed flapper 22 and the supply / discharge flapper 25 are driven.
When the solenoid is off, the reverse feed flapper 2
2. The supply / discharge flapper 25 is at a solid line position in the figure, and when the solenoid is turned on, the reverse sheet supply flapper 22 and the supply / discharge flapper 25 swing to the chain line position in the figure, respectively.

Reference numeral 108 denotes a reverse flapper solenoid which drives the reverse flapper 23. When the solenoid is off, the reversing flapper 23 is at the position indicated by the solid line in the figure, and when turned on, swings to the position indicated by the chain line in the figure.

Reference numeral 109 denotes a discharge flapper solenoid.
The discharge flapper 26 and the manual shutter 28 are driven.

When the solenoid is off, the paper discharge flapper 26 and the manual feed shutter 28 are at the positions indicated by the chain lines in the figure.

When it is on, it swings to the solid line position in the figure.

<Description of Block of Control Circuit> FIG. 12 is a block diagram showing a circuit configuration of a control device according to the present embodiment. The control circuit mainly includes a microprocessor (CPU) 201. The drive circuits of various loads and sensor signals are connected to the input / output port of.

Further, the control circuit includes a RAM backed up by a battery (not shown) and a ROM storing control sequence software. Reference numeral 202 denotes a communication IC for controlling data communication with the copying machine main body.

In FIG. 12, the separation motor 100 (DC
Brush motor) includes a driver 203 and a controller 203
a is controlled by the controller 203a.
, A reference clock serving as a reference for the motor rotation speed, an on / off signal, and the like are input from the CPU 201.

Transport motor 101 (stepping motor)
Are driven by a stepping motor driver 204. Similarly, the belt motor 102 (stepping motor) is also driven at a constant current by the stepping motor driver 205. Each driver receives a phase excitation signal from the CPU 201 and a motor current control signal.

Oscillating motor 103 (stepping motor)
Is driven by a driver 206 at a constant voltage, and the discharge motor 104 (DC brush motor) is driven and controlled by a driver 207 and an FG servo controller 104a.

The motors 100 to 104 have encoders 100a to 104a and detecting means 100b to 104, respectively, as means for detecting the rotational speed of the motors.
b.

Further, the chata solenoid 105 is driven by the driver 208, and the
06 is a driver 209, a bus switching solenoid 107
Is driven by a driver 210, a reversing flapper solenoid 108 is driven by a driver 211, and a discharge flapper solenoid 109 is driven by a driver 212 by a driver 213.

The drivers 203 to 213 are all C
By the signal connected to the input / output port of the PU 201,
Its operation is controlled.

Further, the separation sensor 30, the skew detection sensor 31, the mixed loading detection sensor 32, the reversal detection sensor 33, the manual feed registration sensor 34, the paper feed sensor 35, and the reversal sensor 3
6, manual feed document detection sensor 37, registration sensor 39,
Various sensors such as a document set sensor 40, a document trailing edge detection sensor 41, a final document detection sensor 43, a paper width detection sensor 44, a paper feed roller home sensor 45, a swing position sensor 46, and the like are connected to an input port of the CPU 201, It is used to monitor the behavior of the document and the behavior of the movable load in the apparatus.

The present invention has been described by taking an automatic document feeder as an example. However, the present invention may be applied to an image forming apparatus, for example, a sheet conveying apparatus mounted on a copying machine or a laser beam printer.

The present invention can be applied to various separation apparatuses such as a well-known Duplo pad separation system and a retard separation system in separation means for separating sheets one by one.

[0109]

As described above, according to the present invention,
Since the feed rotator that feeds out the sheet on the stacking means is made hollow with an air layer along the outer circumference, it is easily elastically deformed in the state of contact with the sheet and the contact area with the sheet is smaller than that of the conventional one. The pressure per unit area can be reduced, for example, when the fed sheet is a pencil-drawn original or copy paper that is easy to peel off, the feeding rotating body is attached to the sheet. Since only a low pressing force acts on the contact area, it is possible to prevent a problem that pencil powder and toner powder are re-transferred to the upper surface of a sheet to be fed next and stain the sheet.

[Brief description of the drawings]

FIG. 1 is a vertical sectional front view of an image forming apparatus provided with a sheet conveying device according to the present invention.

FIG. 2 is a vertical sectional front view of the image forming apparatus main body.

FIG. 3 is a vertical sectional front view showing a path of the sheet conveying apparatus.

FIG. 4 is a vertical sectional front view showing a drive system of the sheet conveying apparatus.

FIG. 5 is a side view of the sheet feeding unit and the separation unit.

FIG. 6 is an operation diagram of a sheet feeding unit separation unit.

FIG. 7 is an operation diagram of the sheet feeding unit separation unit.

FIG. 8 is an operation diagram of a sheet feeding unit separation unit.

FIG. 9 is a plan view of a sheet feeding unit of the sheet conveying apparatus.

FIG. 10A is a front view of the paper feeding roller partially cut away, and FIG. 10B is a side view of the paper feeding roller.

FIG. 11 is an operation diagram showing a contact state of a sheet feeding roller with a sheet.

FIG. 12 is a block diagram related to control of the sheet conveying apparatus.

FIG. 13 is a longitudinal sectional front view of an image forming apparatus provided with a conventional sheet conveying device.

FIG. 14 is a side view showing an example of a conventional paper feed roller.

[Explanation of symbols]

 P Sheet document (sheet) 4 Document tray (stacking means) 5 Paper feed roller (feeding rotating body) 6 Separation belt 8 Separation / conveyance roller 6,8 Separation means 501 Rubber member (elastic body) 502 Core member 503 Air layer 504 Air Hole 505 groove

Claims (5)

[Claims] 1. A sheet conveying apparatus comprising: a stacking unit for stacking sheets; a feeding rotator for feeding the sheets on the stacking unit; and a separating unit for separating the fed sheets one by one. A sheet conveying device, wherein the rotating member is made of an elastic body and has an air layer along the outer periphery therein. 2. The feeding rotating body comprises a core member and an elastic body provided around the core member to form an air layer, wherein the air layer has an air hole communicating with outside air. The sheet conveying device according to claim 1, wherein: 3. The sheet conveying apparatus according to claim 1, wherein the feed rotator has a groove on an outer periphery thereof that intersects a circumferential direction. 4. The sheet conveying apparatus according to claim 1, wherein the sheet fed by the feed rotating body is a sheet document having an image. 5. A sheet conveying device according to claim 4, and an image forming means for forming an image based on an image of a sheet document fed by the sheet conveying device and forming an image on a conveyed sheet. And an ejection unit for ejecting a sheet on which an image is formed by the image forming unit.