JPH0373726A - Paper feeding device - Google Patents

Abstract

PURPOSE:To obviate the need of pressing the piled originals and prevent the disturbance of an image due to the contamination, rubbing, etc., of the obverse and reverse surfaces of the original which are generated by the rubbing between the obverse and reverse surface of the originals, by carrying out the feeding and separation sending of the original by an attracting cylinder device consisting of a triple pipe structure and an attracting means. CONSTITUTION:An intermediate pipe part 241 is drive-revolved by a motor, and the opened port part 241A is revolution-shifted in the clockwise direction, and a relative opening angle theta1 formed by the opened port part 251A of an innermost pipe member 251 is stop state is gradually spread, and the opening rate increases. At this time, an outermost pipe member 231 is in stop state. As the opening rate increase, the negative pressure intake air of a suction device attracts the root part of the lowermost original D1 in an original bundle, passing through the opened port parts 251A and 241A and a small diameter through hole 231A, and the root part is separated and attracted onto the peripheral surface of the outermost pipe member 231. Then, the intermediate pipe member 241 drive-revolves furthermore, and the perfect opened state is generated, the original D1 is attracted and closely attached onto the outer peripheral surface of the outermost pipe member 231.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a paper feeding device that separates and sequentially feeds sheets one by one starting from the bottom layer of a stack of sheets stacked on a sheet stack, for example. Improvements in paper feeding devices such as document transport devices used in electronic copying machines and document image readers to separate and feed documents from a stack of documents on a document tray and feed them to the exposure position on the document glass surface. It is related to.

[Background of the invention]

A ``circulating document transport'' device is a paper feeding device that places multiple sheets of originals in a stack on a paper stacker and automatically feeds them onto the copying machine's document stacker. (RDH), automatic document feeder (ADF), etc. In such devices, separation performance at the paper feeding section is extremely important.

A bottom feeding method has been conventionally adopted as a paper feeding method with excellent separation performance. This separates and conveys originals stacked on a paper stacker one by one from the lowest layer to a processing section, and returns the originals after exposure processing to the paper stacker or discharge stacker.

A typical circulating document feeder (li'D) that achieves this
The paper feed device H) has a paper feed port at the bottom end of the paper loading table of the paper feed device, and a sheet of original sent from the first paper feed section near the paper feed port is transferred to the second paper feed section. The upper surface of the platen glass of the copying machine is guided through the paper feed path from the original, and the document is moved to an exposure position by rotation of a conveyor belt provided on the platen glass, and at that position, the exposure optical system is moved back and forth to perform exposure processing. After that, the processed original is re-fed by the rotation of a conveyor belt, and is stacked on top of the stack of originals on the paper stacking table through a circulation path. , the first paper feeding section includes a paper feeding belt that feeds out the lowest document in the stack of documents at the paper feeding position, and a stop roller that comes into pressure contact with the paper feeding belt to prevent double feeding of the documents. .

However, in the case of the above device, when a document at a fixed position on the paper stacker is pushed out to the paper feed position by the extrusion belt, multiple sheets of the document are formed at a time by the paper feed belt and the stop roller. pressed into the wedge-shaped part;
Furthermore, the nip part will dig in.

Moreover, since the stop roller is pressed against the paper feed belt, there are various problems such as image disturbance due to stains and scratches on the front and back surfaces of the documents caused by friction between the front and back surfaces of the documents.

On the other hand, for copying, a plurality of through openings are provided in the endless belt of the paper feeding device that feeds the paper from the document mounting table to the platen glass, and the means for applying negative pressure through the openings in the belt is swingable. A paper feeding device with an eccentric suction drum is disclosed in U.S. Pat. No. 4,345.75i. This proposal feeds and aligns documents from the document placement table toward the document stop position on the opposite side of the copying machine's platen glass, without using the movable W document stopper 7 of the document feeder. * Such a plurality of endless belts tends to cause speed unevenness when rotating, and as a result, the fed paper may be distorted. If such distortions are not removed prior to copying, a copied image will not be accurately formed on the yK product image recording paper. Further, this paper feeding device has a complicated structure and operation, and in particular, the suction drum's moving mechanism is complicated.

In addition, as another conventional technology, a protrusion is provided on the upper surface of the document tray, a suction box is provided on the lower surface, and a blower is provided in front of the document tray downstream of the document conveyance. The center area is made wavy by protrusions,
A paper feeding device has been put into practical use in which a blower blows air to the leading edge of the wavy original to create ventilation between the originals, and the suction box separates and feeds out the bottom layer of the original sheet by sheet (U.S. Pat. No. 4,284,270
No. 4,324,395, No. 4,411.417).

However, with these paper feeding devices, ■The surface shape of the document mounting table is irregular and the shape of the suction box makes it difficult to handle documents of various sizes. ■The air gap suction requires lead time, and the paper feeding speed is high. unsuitable for
There are problems such as the need for a special blower, complicated control, and high cost.

[Problem to be solved by the invention]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object thereof is to provide a paper feeding device that prevents stains, image disturbances, etc. that occur on the surface of a document when feeding the document.

[Means to solve the problem]

This invention, which is distantly related to the above object, provides a paper feeding device that separates and sequentially feeds sheets one by one from the bottom layer of a stack of sheets stacked on a paper stack, in the feeding direction of the paper stack. Below near the front end, there is a first cylinder that can be driven and rotated by having a number of small openings bored in the circumferential surface of the pipe-like cylinder; A triple pipe consisting of a second cylinder having an opening, a third cylinder having a slit-like opening on the circumferential surface of a pipe-like cylinder inside the second cylinder, and a suction device connected to the third cylinder. This is achieved by a paper feeding device characterized by a mechanism that separates and feeds paper by suction.

Further, the paper feeding device according to the present invention includes the first cylinder;
The second cylinder and the third cylinder are arranged coaxially, and the cylindrical surface of each cylinder forms a concentric circle.

Furthermore, the paper feeding device according to the present invention includes the second cylinder;
The present invention is characterized in that one of the third cylinders is rotatable and the other cylinder is fixed.

〔Example〕

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

The embodiment described below is applied to a circulation document conveyance device (RDH) that conveys documents in a circulation manner.

Note that the paper feeding device of the present invention is not limited to these embodiments, but can also be applied to automatic document feeders (ADF), document reading devices, and the like.

FIG. 1 is a front cross-sectional view showing a circulation type document conveying device 200 provided on a main body 100 of a copying machine. In FIG. 1, 100 is a main body of a copying machine, and 200 is a circulating document conveying device to which the paper feeding device of the present invention is applied. The circulation type document conveyance device 200 includes a document stacker 201 (corresponding to a paper mounting table) whose front portion on the downstream side in the document conveyance direction is curved.
On the *ta stacker 201, there are provided a trailing edge regulating plate 202 for abutting the rear end of the document tray when setting the document tray, and a width regulating plate 203 for regulating the width direction of the document tray.

The width regulating plate 203 is connected to a pair of rack gears 205, 205 on the lower surface of the document stacker 201, which can alternately slide laterally with a pinion gear 204 in between, and is movable symmetrically about the center line of the width of the document. In addition, by detecting the movable position of the width regulating plate 203 with a sensor (not shown), the width size of the document can be read. Further, the trailing edge regulating plate 202 has a function of pushing out the leading edge of the document set on the document stacker 201 to the detection position (normal position) of the document stopper 208 and the stack sensor 206.

Reference numeral 208 denotes a document stopper 7 that is disposed close to the paper feed port of the document table 201 in the paper feed direction, and is fixed to the frame of the paper feed section.

A blower means 270 is provided on the back side of the document stopper 208, and blows air from a lower blower port 271 to play an auxiliary role in separating the documents.

Reference numeral 207 denotes a document set detection sensor that detects whether or not a document tray is set on the document table 201 . The detection sensor 207 is placed on the upper moving body 208 at the front upper part of the rear end regulating plate 202, so that it can move integrally with the regulating plate 202.

The detection sensor 207 detects when the document stacker is stopped at its original position on the document stacker 201, when the document tray is sliding on the document stacker 201 with its rear end being pressed, and when the document tray is in its original position on the document stacker 201. In any case when the leading edge reaches the paper feeding start position, it is possible to always optically detect whether or not the document tray is set on the document stacker 201, so that the document tray is placed on the document tray 201. It is possible to prevent unnecessary copying such as starting a copy operation even though the setting is not set.

The document set detection sensor 207 is fixedly mounted on the paper discharge log guide plate of the upper stage moving body 209 with its front portion protruding forward. A through hole is bored in the front lower surface of the frame body to which the detection sensor 207 is attached, and light projected from the frame body of the detection sensor 207 and light reflected to the detection sensor pass through the frame through hole. It is supposed to be done. Above detection sensor 2
07 is a detection sensor in which a light emitting part and a light receiving part, which are constituted by a light emitting LED and a phototransistor, are provided in the same frame. The projection light projected from the light projection part (light emitting LED) passes through the frame through-hole and reaches the reflection plate 202a that integrally projects forward from the lower edge of the rear end regulating plate 202. The light reflected by the reflection plate 202a passes through the frame through-hole again and reaches the light receiving section (phototransistor).

A rear end regulating plate 202 and a document set detection sensor 207 are attached to the upper moving body 209, and in addition to these, a device (set separator) 210 for separating documents is suspended near the center and integrated. is doing.

In the above-mentioned circulating document conveying device, it is necessary to detect the circulation of the document. This document classification is device 2.
10, a partition arm (separator) 211 is attached in advance to the top layer of the stack of documents stacked on the document stacker 201.
The stack of circulated documents is sequentially stacked on the upper part of this partition arm, and when the last document pressed against this partition arm 211 is fed to the exposure position, the partition arm 211 is When the last page is moved back from the placement position and returned to the document placement table and placed on the top layer of the document stack, the partition arm 211 comes into pressure contact with the top layer of the document stack.

Further, on this upper stage moving body 209, an upper end roller 213 that is rotated by a paper ejection belt 212 and a driven roller 214 that is in pressure contact with the upper end roller 213 and rotates as a result of rotation are pivotally supported. The paper ejection belt 212 includes a drive roller 215 connected to a main motor via a one-way control A1 mechanism, and an upper end roller 213 that is pivoted so as to be movable horizontally along the upper and lower surfaces of the document stacker 201. The lower end roller 216 and the auxiliary rollers 217, 218, 219 are stretched so as to wrap around the rear side of the document stacker 201 in a C-shape. It is possible to transport documents sent out from the paper in the paper ejection direction.

220 is a conveyor belt for conveying the document in the forward direction and the reverse direction on the upper surface of the platen glass 102. This conveyor belt 220 is connected to the main motor via a forward/reverse switching means, and is stretched between a first roller 221 on the sheet feeding side and a second roller 222 on the sheet discharging side.

A tension roller 223 is in pressure contact with the upper belt surface near the first roller 221, and the lower belt surface is pressed against the platen glass 10 by a plurality of pressing rollers 224, 224, 224.
It is designed to come in sliding contact with the

The first roller 221 and the second roller 222 are connected to each other by a timing belt (not shown). When the conveyor belt 220 rotates in the forward direction (clockwise in FIG. 1), it runs by the driving force from the first roller 221, and the lower belt surface is on the slack side. In this case, the second roller 222
is designed to slip between the one-way clutch and the one-way clutch. When the conveyor belt 220 is rotated in the opposite direction (counterclockwise), the one-way rotation is locked and the second roller 222 becomes the driving side of the conveyor belt 220. That is, the conveyor belt 220 may run with the first roller 221 on the driving side, or may run with the second roller 222 on the driving side. This is particularly effective when synchronized exposure is performed while the document is being fed on the platen glass 102.

Reference numeral 103 denotes a document stopper provided at the end of the platen glass 102 on the paper discharge side, and is capable of moving in and out of the platen glass 102. This document stopper 103
In this case, the original is transferred to the conveyor belt 22 as in the original circulation copying mode.
0, the exposure optical system 110, which is provided directly below the platen glass 102 and has a selectable mode of fixation in a fixed position or movement, exposes the photoreceptor drum while being transported at a synchronous exposure speed over the platen glass 102. When creating an image, the original is lowered through the platen glass 102, stopped at the exposure position on the platen glass 102 as in the ADF or SDF mode, and exposed while moving the optical system 110, and placed on the drum. When an image is to be created, it operates so as to protrude above the platen glass 102.

Reference numeral 225 denotes a paper discharge guide plate continuous to the exit side of the platen glass 102, and 226 indicates a paper discharge guide plate provided in the middle of the paper discharge guide plate 225, which guides the processed originals to the circulation paper discharge path B toward the document stacker 201 and the discharge outside the machine. It is a switching claw that switches between the external paper ejection path C toward the paper plate 227, and when the trailing edge regulating plate 202 returns to the home position, it moves to open the external paper ejecting path C, and the trailing edge regulating plate 202 When it is not at the home position, it is movable so as to open the circulation paper discharge path B.

In addition, E is the document reversal path when copying a double-sided document.
The original document is reversed in a somersault shape along this path E and conveyed onto the platen glass 102 again.

Reference numeral 230 denotes a suction cylinder device that separates each document sheet from the stack of documents in a fixed position as described above and feeds them onto the platen glass 102.

FIG. 2 is a partially sectional plan view of the suction cylinder device. FIG. 3 is a perspective view of the outermost tube member of the cylinder device;
The figure is a perspective view of the intermediate tube member, and FIG. 5 is a perspective view of the innermost tube member.

The cylinder device 230 includes an outermost tube member (first cylinder) 231, an intermediate tube member (second cylinder) 241, an innermost tube member (third cylinder) 251, and a driving means for driving and rotating these tube members. It consists of

The outermost tube member (first cylinder) 231 is formed of a circular thin pipe made of aluminum alloy, and has a large number of small-diameter through holes 231A bored on its outer circumferential surface, and is coated with synthetic rubber on its outer circumferential surface. Covered. The above small diameter through hole 231
The diameter of A is 3 to 10 mm, and they are arranged in a folded or staggered pattern. In addition, the covering synthetic rubber is a material with a high coefficient of friction and excellent strength, heat resistance, low temperature resistance, abrasion resistance, oil resistance, adhesiveness, etc., such as evaporated ethylene propylene rubber (
EPDM), chloroprene rubber, urethane rubber, styrene rubber, acrylic rubber, butyl rubber, butadiene rubber, silicone rubber, fluororubber, etc., and is formed into a uniform film thickness by coating, spraying, etc.

Flanges 232 and 233 are fitted into the inner diameters of the openings on both sides of the outermost tube member 231 and are integrated therewith.

A bearing BRI is fitted into the inner diameter portion of the flange 232, and the bearing BRI is coupled to a suction pipe 235 attached to the side plate 234. It is fitted onto the outer wall of the suction connection pipe 236 and supported rotatably.

A gear 232G is integrally formed in a part of the outer diameter portion of the seven flange 232. The drive rotation of the pinion gear Gll by the motor Ml is caused by the rotation of the gear G12 on the first intermediate shaft 237.
and the toothed pulley pH, and further rotate the toothed belt Bl.
The toothed pulley PI2 and the gear GI3 connected to the clutch on the second intermediate shaft 238 are rotated, and the gear G is rotated.
A gear 232G fixed to one end of the outermost tube member 231 that meshes with I3 is rotated.

At the same time, the toothed bell 1-Bl is transferred to the intermediate conveying roller 26 via a third intermediate shaft (same shape as the second intermediate shaft) (not shown).
1,262 (see Figure 1). 263 is a guide plate, and 264 is a document leading edge detection sensor.

A bearing BH2 is fitted to the outer diameter of the boss portion of the seven flange 233 at the other end of the outermost tube member 231, and the bearing BH2 is fitted and supported by a support member 239 attached to the side plate 240. Therefore, both ends of the outermost tube member 231 are connected to the side plates 23
4.240 is rotatably supported. The outermost tube member 231 plays the role of conveying original documents one by one in close contact with the cylindrical surface of the tube by being inserted into the tube through the small diameter through hole 231A, and is controlled to drive, rotate, and stop.

Next, the intermediate tube member (second cylinder) 241 is formed of, for example, a circular thin-walled pipe made of aluminum alloy, and has a rectangular opening 241A in a part of its outer peripheral surface.

241A, 241A, 241A are drilled.

The opening angles (α) of these openings 241A are set to 10' to 80°.

Flanges 242 and 243 are fitted into the inner diameters of the openings on both end surfaces of the intermediate tube member 241 and are integrated therewith.

A bearing BH3 is fitted into the inner diameter portion of the seven flange 242, and the bearing BH3 is fitted onto the outer peripheral surface of the suction connection pipe 236 and is rotatably supported.

A bearing BH4 is fitted to the outer diameter of the boss portion of the other 7 flange 243, and by fitting to the 7 flange 233 via the bearing BH4, the 7 flange 243 is connected to the flange 23.
3 is rotatably supported.

A toothed pulley P22 and a cam plate 244 are fixed near the tip of the boss portion of the seven flange 243. The drive rotation of the pinion gear G21 by the motor M2 passes through the gear G22 loosely fitted to the first intermediate shaft 245, and then to the second intermediate shaft 24.
The gear G23 and the gear pulley P21 of No. 6 are rotated, and the toothed belt P22 is rotated via the toothed belt B2.

Further, the cam plate 244 opens and closes the optical path of a photointerrupter (transmissive optical coupling element) 247, and
41 is controlled.

The intermediate tube member 241 functions as a shutter for suctioning and separating the document by suction from its opening 241A, and performs driving rotation and stopping, and stops once every time one document is sent.

Next, the innermost tube member (third cylinder) 251 is formed of, for example, a circular thin-walled pipe made of aluminum alloy, and has a rectangular opening 251A in a part of its outer peripheral surface.

251A, 251A, and 251A are drilled.

The opening angles (β) of these openings 251A are set to lOo to 80°.

FIG. 6 is a developed plan view of the innermost tube member 251 and an explanatory diagram showing the relationship with various document sizes.

On the circumferential surface of the innermost tube member 251, three tubes having different lengths in the axial direction are provided.
Different types of openings 251A, 251B, and 251C are bored. The opening 251A is for the 85-size vertical size (2
57mm) and A4 size vertical size (297mm) +21. For example, it is set to about 295 mm. The opening 251B accommodates 84-size vertical size (36-inch) originals.
4 mm), for example, approximately 360 mm.

Opening 25IC is for A3 size document (420mm)
), for example, approximately 420 mm.

Seven flanges 252 and 253 are fitted into the inner diameters of the openings on both end faces of the innermost tube member 251 and are integrated therewith.

One of the seven flange 252 is rotatably supported on the outer circumferential surface of the suction connection pipe 236 via a bearing BH3, similarly to the seven flange 242.

The boss portion of the other flange 253 is fitted into the plunger 243 via a bearing BH6 and is rotatably supported. A drive shaft 254 is fixed to the boss portion of the seven langes 253. The drive shaft 254 loosely passes through the boss portion of the flange 243, and a toothed pulley P32 and a cam plate 255 are fixed to one end thereof.

The toothed pulley P32 is driven by a motor (M3) not shown. Its driving means is the same as the gear train, toothed pulley, and belt driven by the motor M2.

The cam plate 255 also includes a photo interrupter 256.
The rotation of the innermost tube member 251 is controlled by opening and closing the optical path.

The innermost tube member 251 rotates depending on the document size, is controlled to a predetermined position and stops, and selects an opening having an optimum length corresponding to the document size.

Next, the operation of the circulating document feeder (RDH) equipped with the paper feeding device according to the present invention will be explained with reference to the constituent countries shown in FIGS. The explanation will be based on a cross-sectional view of the cylinder device and a time chart in FIG. 9.

■The trailing edge regulating plate 202 is in the home position with the originals stacked and the copy side facing up, aligned in page order from the top.
Place the document on the document stacker 201 with its rear end against the document stacker 201.

■ The width direction of the document is regulated and arranged using the width regulating plate 203.

This will detect the original size and input and store it (
Original size determining means 228).

■Enter the number of copies to be made and turn on the copy button.

■This allows the document to be separated by device (set separator) 2.
10 rotates, and the original set detection sensor 2
07 detects and confirms the presence or absence of a document.

■By the original size signal according to the above ■, the innermost tube member 25
1 is rotated by motor M3 and stops at a predetermined position.

That is, the suction width is changed thereby. Figure 8 (A)
indicates the state immediately before the start of suction.

In this state, the opening 241A of the intermediate tube member 241,
The opening 251A of the innermost tube member 251 is stopped in a mutually closed shape.

■Next, the drive source M4 of the paper ejection belt 212 is started, and the upper end roller 213, which is pivoted on the upper stage moving body 209, moves forward in the paper feeding direction.The lower end, which is pivoted on the lower stage moving body The roller 216 is moved backward in the paper feeding direction. The trailing edge regulating plate 202 attached to the upper moving body 209 moves forward while pushing the trailing edge of the document stack, and the stack sensor 202 detects that the leading edge of the document tray has hit the document stopper 208.
When detected, the drive source M4 is stopped by the action of the controller a219. (See Figure 7). At this time, the vicinity of the leading end of the document bundle overhangs due to the contact position with the outermost tube member 231, and is kept in an overhanging state due to the stiffness of the paper without being supported in any way. (See Figure 8(A)).

■Next, the suction means of the suction cylinder device 230 is turned on, and the negative pressure air from the suction source passes through the tube to the suction pipe 2.
35. Apply negative pressure inside the innermost tube member 251 from the suction connection tube 236. At the same time, the blowing means 270 is also turned on, and pressurized air is blown out from the blowing port 271 to the suction cylinder device 23.
0 onto the outer peripheral surface of the outermost tube member 231. but,
Outermost tube member 2311 Middle tube member 2411 Innermost tube member 25
1 is stopped, and the openings 241A and 251A are in a mismatched state as shown in FIG. 8(A), so they are not through openings, and the document cannot be sucked.

■Subsequently, the intermediate tube member 241 is driven and rotated by the motor M2, the opening 241A rotates clockwise, and the relative opening angle θl formed by the opening 251A of the innermost tube member 251 in the stopped state gradually changes. The area is expanded and the aperture ratio increases (see FIG. 8(B)). Note that at this time, the outermost tube member 231 is stopped. With this increase in the aperture ratio, the negative pressure suction of the suction device moves the base of the lowest document Dl in the document bundle to the opening 251A.

241A, 8 and the small-diameter through hole 231A, and are separated by suction, and are adsorbed onto the circumferential surface of the outermost tube member 231.

■The intermediate tube member 241 is further driven to rotate, and the opening 241
When A and 251A reach the fully open state (FIG. 8(C), relative amount B angle θ2, aperture ratio 100%), the original Di opens into openings 251A, 241A and small diameter through hole 23.
It is sucked in by the negative pressure air passing through 1A, and is brought into close contact with the outer circumferential surface of the outermost tube member 231.

[Phase] While maintaining this document suction state, the clutch K is turned on and the outermost tube member 231 is rotated by the driving force of the motor Ml. The original D attracted to the outer peripheral surface of the outermost tube member 231
i moves while being attracted by the rotation of the outermost tube member 231, and is pulled out from the bottom of the document bundle and conveyed. Manuscript D
The leading edge of the document l advances along the inner surface of the guide plate 263, the document leading edge detection sensor 264 detects the passage of the document leading edge, and after the document leading edge is nipped at the nip position of the intermediate conveyance rollers 261 and 262, the clutch K is activated. is turned OFF, the rotation of the intermediate conveyance rollers 261 and 262 is temporarily stopped, and the copying machine body 100 waits for timing with the transfer paper by the registration rollers of the paper feeding device. FIG. 8(D) is a partial sectional view of the paper feeding device showing this standby state.

(2) Timing of transfer paper In response to the paper feed start signal, the intermediate conveyance rollers 261 and 262 begin to rotate again, and convey the leading edge of the original document Dl to the pressure position between the conveyance bell l-220 and the platen glass 102 shown in FIG. During this conveyance, the outermost tube member 231 is rotated by the document feed. Further, the intermediate tube member 241 is driven and rotated clockwise as indicated by the arrow to the initial position (
It stops when it reaches FIG. 8(A)).

■Thus, one document Di sent out by the suction cylinder device 230 enters the forward path A, is nipped by intermediate conveyance rollers 261 and 262 provided on the way, and is synchronized toward the platen glass 102 and the conveyance belt 220. Transported at exposure speed. The rear end of the document Di is the suction cylinder device 2
When the document leading edge detection sensor 264 detects that the document has passed the document 30, suction of the next document is started again.

■The document DI transported by the intermediate transport rollers 261 and 262 is transported by the transport belt 220 over the platen glass 102 at a synchronous exposure speed, and is exposed to light by the fixed optical system 110 to form an image on the photoreceptor drum. . The original DI after exposure processing moves upward along the paper ejection guide plate 225,
The paper is discharged toward the document stacker 201 by the paper discharge belt 212.

Further, the document Dl discharged onto the document stacker 201 is
The front and rear ends are aligned by the document stopper 208 and the trailing edge regulating plate 202, and the documents are stacked again with the widths being aligned by the width regulating plates 203 and 203. Also, it is placed first;
The document bundle and the circulated document Di are classified into device 2.
Sorted by 10. The above-mentioned feeding operation is repeated until there is no remaining document on the document stacker 201. Then, when the stack sensor 206 detects that there is no remaining document left, and the paper ejection sensor detects that the last document has been ejected, the trailing edge regulation plate 202 feeds out the stacked document, and the stack continues until the set number of copies is completed. Repeat the action. When the set number of copies is completed and the number of copies is detected by the paper discharge sensor, the trailing edge regulating plate 202 returns to its home position and prepares for the next operation. The above operation is performed when a one-sided original is copied on one side in the RDH mode. Further, when a double-sided original is to be copied on one side in the RDH mode, or when a double-sided original is to be copied on both sides, the original is introduced into the reversing path E.

FIG. 10 is a sectional view showing another embodiment of the triple tube structure paper feeder according to the present invention. In this embodiment, the middle second cylinder 281 is fixed, and the innermost third cylinder 29
1 can be rotated.

FIG. 10(A) shows the state immediately before the start of paper feeding, where the opening 281A of the second cylinder 281 and the opening 291A of the third cylinder 291 intersect and are in a closed state (opening ratio 0%). ). FIG. 10(B) shows a state in which the third cylinder 291 is rotated clockwise by an angle θ2, and the openings 281A and 291A match to be in an open state (opening ratio 10.0%). In this state, as described above (see FIG. 8(C)), the document DI is sucked by the negative pressure air passing through the openings 281A, 291A and the small diameter through hole 231A of the first cylinder 231, and the document DI is drawn to the outer periphery of the first cylinder 231. It is rotatably fed in a clockwise direction while being in close contact with the surface.

In any of the above cases, the suction cylinder device 230 with the triple tube structure according to the present invention is effective when applied to a document bottom-feeding W or Hanawa conveyance device. It is also applicable to

〔Effect of the invention〕

As described above, the present invention provides a feeding device that feeds a stack of originals placed in a stacked manner on a document stacker in the feeding direction, and separates and feeds the stack of originals one by one starting from the bottom layer using a separating means. Since the suction cylinder device consisting of a triple tube structure and a suction means is used to feed and separate the originals, there is no need to press the stacked originals, and there is no need to press the stacked originals. It is possible to prevent image disturbances due to dirt, scratches, etc. on the back side. Moreover, the document separation performance is improved, and even thin documents can be reliably separated and fed. In addition, since the perforated external tube provides suction all around the document, the surface of the document is evenly attracted and fed, eliminating wrinkles and skewed feeding.

[Brief explanation of drawings]

FIG. 1 is a front cross-sectional view of a document conveying device showing an embodiment of the paper feeding device according to the present invention, FIG. 2 is a partial cross-sectional plan view of the triple tube mechanism of the device shown in FIG. 1, and FIG. 4 is a perspective view of the second cylinder, FIG. 5 is a perspective view of the third cylinder, FIG. 6 is an explanatory diagram showing the relationship between the developed plan view of the first cylinder and document size, and FIG. 7 (A), (B)
Figures 8(A) to 8(E) are configuration diagrams of the circulating document conveyance device.
9 is a sectional view explaining the paper feeding process of the paper feeding device, FIG. 9 is a time chart of the paper feeding process, and FIGS. 1O (A) and (B) are cross sections of the paper feeding device showing another embodiment of the present invention It is a diagram. 100...Copying machine main body 102...Platen glass (original plate) 103...
・Document stopper 110...Exposure optical system 200・
...Document transport device 201...Document stacker (paper mounting table) 202...
Rear end regulating plate 203... Width regulating plate 206...
・Stack sensor 207...Original set detection sensor 208...Original stopper 209...Upper moving body 210...Original classification is performed by device (set separator) 2
12... Paper discharge belt 215... Drive roller 220.
...Conveyor belt 221...First roller 222
...20th-ra 230...Suction cylinder device 231...Outermost tube member (first cylinder) 241.2
81... Intermediate pipe member (second cylinder) 251.291
... Innermost tube member (third cylinder) 231A ... Small diameter through hole 232 ... 7 langes 233 ... Flange 234 ... Side plate 235 ... Suction pipe
236...Suction connection pipe 240...Side plate
241A, 291A...opening 242...7
Lunge 243...7 Lunge 244...Cam plate 245...First intermediate shaft 246...Second
Intermediate shaft 247...Photo interrupter 251A, 251B, 25IC, 281A, 281B,
28IC...opening 252...7 lunge
253...Flange 254...Drive shaft 2
55...Cam plate 256...Photo interrupter 261.262...Intermediate conveyance roller 263...Guide plate 264...Document leading edge detection sensor

Claims (3)

[Claims] (1) In a paper feeding device that separates and sequentially feeds sheets one by one from the bottom layer of a stack of sheets stacked on a sheet stack,
Below near the front end of the sheet loading table in the feeding direction, there is a first cylinder which is rotatable and has a plurality of small openings drilled in the circumferential surface of a pipe-shaped cylinder, and a pipe-shaped cylinder inside the first cylinder. a second cylinder having a slit-like opening on the circumferential surface of the cylindrical body; a third cylinder having a slit-like opening on the circumferential surface of the pipe-like cylindrical body inside the second cylinder; and a suction connected to the third cylinder. A paper feeding device characterized in that paper is separated and fed by suction using a triple tube mechanism comprising a device and a triple tube mechanism. (2) The paper feeding device according to claim 1, wherein the first cylinder, the second cylinder, and the third cylinder are arranged coaxially, and the cylindrical surface of each cylinder forms a concentric circle. (3) The paper feeding device according to claim 1 or 2, wherein one of the second cylinder and the third cylinder is made rotatable and the other cylinder is fixed.