JPH0383733A - Paper sheet feeder - Google Patents

Abstract

PURPOSE:To separate and feed a paper sheet securely with enhanced original paper sheet separating performance even if the paper sheet is thin by employing air blow means constituted to blow out pressurized air onto an outer side cylinder surface and onto a position near the force-end of a paper sheet stock so that a lowermost sheet is separated from the rest of the paper sheet stack. CONSTITUTION:Blower means 270 is provided on the back of an original stop 208. The blower means 270 has a blower pipe extending in the direction of the width of the paper sheet. One end of the blower pipe is provided with a blower fan and a motor. A plurality of small-diametered blow holes 271 are arranged on the side opposite an outermost pipe member 231 and below the blower pipe. Air blown by the motor and the fan is blown through a blow pipe, from the plurality of blow holes 271 onto the surface of the outermost pipe member 231. At the time of starting suction and feed, the force-ends of the plurality of paper sheets D are separated by the air blown into the gaps between the paper sheets, and only one sheet D1 is sucked to the 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. Related to 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 to an exposure position on the glass surface of the document tray. It is something.

[Background of the invention]

A circulating document feeder (original document feeder) is a paper feeding device that places multiple documents in a stack on a paper stacker (original stacker) and automatically feeds the sheets onto the document stacker (platen glass) of a copying machine. RDH), automatic document feeder (ADF), etc. are used. In such devices, separation performance at the paper feed section is extremely important.

A bottom feeding method has been used 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 (RDH) that achieves this
The paper feed device has a paper feed port at the lower end of the paper loading table of the paper feed device, and a sheet of original sent from the M1 paper feed section near the paper feed port is fed from the second paper feed section. The upper surface of the platen glass of the copying machine is guided through the path, the document is moved to the exposure position by the rotation of the conveyor belt provided on the platen glass, and the exposure optical system is reciprocated at that position to perform the exposure process. A bottom-feed stacking method in which processed documents are re-fed by the rotation of a conveyor belt and stacked on top of the stack of documents on the sheet stack through a circulation path. The 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 presses against the paper feeding belt to prevent double feeding of the documents.

However, in the case of the above-mentioned device, when the original at a fixed position on the paper stacker is pushed out to the paper feed position by the extrusion belt, multiple sheets of the original are pushed out at a time by the wedge-shaped portion formed by the paper feed belt and the stop roller. pushed into
Furthermore, the nig 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.

As a measure to solve the above-mentioned problems, a separate feeding system has been proposed that utilizes the suction force or blowing force of air.

The first method is disclosed in U.S. Pat. No. 4,345.751 and the like, and is a rotary suction and separation method using a combination of a swinging vacuum cylinder and a conveying section. In this method, a vacuum suction cylinder is installed near the tip of the paper stack stacked on the paper stacker, and the air suction force of the vacuum cylinder is used to remove only the bottom sheet of the paper stack.
This is a sheet feeding device that separates the sheet stack from the stack of sheets located in the upper layer, swings downward in close contact with the curved surface of the cylinder, and feeds the sheet, and then passes the sheet to the next conveyance section. Note that, after the vacuum cylinder has completed receiving and passing one sheet, its opening is returned to just below the original stack of sheets.

The paper feeding device of this proposal has a mechanism that swings the vacuum cylinder, turns on the vacuum suction when feeding a sheet, and turns off the suction when the cylinder returns. [It requires an H structure and operation, and has the drawback of being large. That is, the vacuum cylinder and the conveyance roller for the vacuum belt (negative pressure belt) must be eccentric, and the inside thereof is divided into two ducts.

Further, such a plurality of endless negative pressure belts tend 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, an accurate copy of the original image will not be formed on the recording paper. Further, this paper feeding device has a complicated structure and operation, and in particular, the swinging mechanism of the suction drum is complicated.

In addition, as a second paper feeding method of other prior art, air knife disclosed in U.S. Pat. No. 4,284.270, U.S. Pat. There is a method of handling.

This method uses a vacuum suction belt with a convex shape in the center to suck the bottom sheet of a stack of paper, creates a space between it and the stack of paper on top, and sends pressurized air into that space to separate the stack of paper. The sheet is floated and only the bottom sheet is fed by a vacuum suction belt.

After the vacuum suction belt transfers the sheet to the next conveyance roller, it is necessary to stop vacuum suction until the rear end of the sheet is removed. This is because if the vacuum suction is continued, problems such as friction between the vacuum suction belt and the sheet and tangled feeding will occur. That is, the vacuum suction belt unit needs to turn on and off the vacuum state every time one sheet is fed. Therefore, the time required for the vacuum suction belt to start suction (preliminary suction time) is
A certain amount of time is required (approximately several hundred milliseconds). This preliminary time is due to the response of the electromagnetic clutch (30~
50n+s), the response delay is about 10 times longer. Therefore, this air knife handling method has poor high-speed followability and is unsuitable for increasing the speed of sheet separation and feeding. In addition, a special blower is required, the control is complicated, and there are problems such as noise generation and high cost.

[Problem to be solved by the invention]

This invention is intended to solve the above-mentioned problems, and is capable of reliably and stably separating and feeding sheets during high-speed sheet feeding, as well as damage to originals and stains on the original surface that occur when feeding originals, which are disadvantageous due to frictional handling. An object of the present invention is to provide a paper feeding device for the purpose of preventing image distortion and the like.

Another object of the present invention is to provide a paper feeding device that achieves the above objectives, has a small size and simple structure, and has reliable operation and control.

[Means to solve the problem]

A paper feeding device of the present invention that achieves the above object is 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 paper stack. A drive rotatable outer cylinder having a plurality of small openings drilled in the circumferential surface of a pipe-shaped cylindrical body below near the front end in the feeding direction;
It is composed of at least one inner cylinder disposed inside the outer cylinder and having a slit-like opening on the circumferential surface of a vibrator-like cylinder, and a suction device connected to the inner cylinder, and a suction device connected to the inner cylinder, and A vacuum feeding means for suctioning and transporting paper is provided, and pressurized air is discharged onto the outer cylinder surface and near the front end of the paper stack to separate the lowest layer of paper from the rest of the paper stack. The present invention is characterized in that a blowing means configured as follows is provided.

〔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.

11th! I is a front cross-sectional view showing a circulation type document conveying device 200 provided on the main body 100 of the 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. A trailing edge regulating plate 202 for abutting the rear end of the document and a width regulating plate 203 for regulating the width direction of the document are provided.

The width regulating plate 203 is connected to a pair of rack gears 205 and 205 that can alternately slide laterally across the pinion gear 204 on the lower surface of the document stacker 201, 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, a small hole is formed on the surface of the document stacker 201,
A zero original document detection sensor 206 is arranged below it. The sensor 206 detects the presence or absence of a document placed on the document stacker 201 and controls the control panel 110.
Displays the ADF mode.

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 document stopper 208 .

Reference numeral 208 denotes a document stopper 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 209 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, and when the document tray is sliding on the document stacker 201 with its rear end being pressed, and *fliD is also detected. 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 2θ1, 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 1 m (light emitting LED) passes through the frame through hole and reaches the reflection plate 202a integrally projected forward from the lower edge of the rear end regulating plate 202. The reflected light reflected by the reflection plate 202a passes through the frame through-hole again and reaches the light receiving S (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 is suspended near the center to separate the documents. I am doing it.

In the above-mentioned circulation type document conveyance device, it is necessary to detect circulation of the document. Therefore, the document classification is performed by the device 210.
is stacked on the document stacker 201; a partition arm (separator) 211 is placed in advance on the top layer of the document stack, and the circulated document stacks are sequentially stacked on the top of this partition arm; When the last document pressed against the document stack 211 is fed to the exposure position, the partition arm 211 is retracted from the document placement position, and the last page returns to the document placement table and is placed on the top layer of the document stack. When placed, the partition arm 211 presses against the top layer of the document bundle.

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 an 11-movement roller 215 connected to a main motor via a one-way control 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, and 219 are stretched to wrap around the rear side of the document stacker 201 in a C-shape, and rotation of the drive roller 215 in a fixed direction causes the conveyor belt to 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 includes a first roller 221 on the paper feeding side connected to the main motor via a forward/reverse switching means;
It is stretched between the second roller 222 on the paper discharge 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 in sliding contact with the platen glass 102 by a plurality of pressing rollers 224, 224, 224.

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. Furthermore, when rotating the conveyor bell l-220 in the opposite direction (counterclockwise), the one-way clutch is locked;
The second roller 222 becomes the drive 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 is provided in the middle of the paper discharge guide plate 225; A switching claw that switches between the external paper discharge path C toward the paper discharge tray 227 and the rear end regulating plate 202.
When the paper returns to the home position, exit path C
When the trailing end regulating plate 202 is not at the home position, it is movable 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 vacuum feeding means (suction cylinder device) that separates each sheet from the stack of originals 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. FIG. 8(A) is a sectional view of a main part of a paper feeding device including the above-mentioned suction cylinder device.

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 made of synthetic leather rubber on its outer circumferential surface. is 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 that has a high coefficient of friction and has excellent strength, heat resistance, low temperature resistance, abrasion resistance, oil resistance, adhesiveness, etc., such as evaporated ethylene propylene rubber (
EPDM), chloroprene rubber, tan/tan rubber, styrene rubber, acrylic rubber, butyl rubber, butadiene rubber, silicone rubber, fluorine rubber, etc.
It is formed into a uniform film thickness by spraying or the like.

Seven flanges 232 and 233 are fitted into the inner diameter 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 seven flange 232, and the bearing BRI is coupled to the 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 then the toothed belt B1
The toothed pulley P12 and the gear G13 connected to the clutch on the second intermediate shaft 238 are rotated, and the gear G
A gear 232G fixed to one end of the outermost tube member 231 that meshes with the outermost tube member 231 is rotated.

At the same time, the toothed belt Bl is transferred to the intermediate conveyance roller 261 via a third intermediate shaft (same shape as the second intermediate shaft) (not shown).
, 262 (see Figure 1). 263 is a guide plate, and 264 is a document leading edge detection sensor.

A bearing BR2 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 BR2 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 suctioning documents into the tube through the small-diameter through hole 231A, thereby suctioning and closely conveying documents one by one to its cylindrical surface, 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.

241^, 241A, and 241A are drilled.

The opening angle a (see FIG. 8(A)) of these openings 241A is set to lOo to 80@.

Seven flanges 242 and 243 are fitted into the inner diameter of the opening on both end surfaces of the intermediate tube member 241 and are integrated therewith.

A bearing BR3 is fitted into the inner diameter portion of the seven flange 242, and the bearing BR3 is fitted onto the outer peripheral surface of the suction connection pipe 236 and is rotatably supported.

A bearing BR4 is fitted onto the outer diameter of the boss portion of the other 7 flange 243, and by fitting into the 7 flange 233 via the bearing BR4, 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 flange 243. Motor M
The drive rotation of the pinion gear G21 by 2 is transmitted through the gear G22 loosely fitted to the first intermediate shaft 245, and then to the second intermediate shaft 246.
The gear G23 and the gear pulley P21 are rotated, and the toothed bell P22 is rotated via the toothed belt B2.

Further, the cam plate 244 opens and closes the optical path of a photo ink clubter (transmissive optical coupling element) 247, and the intermediate tube member 247
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 vibrator 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 angle β (see FIG. 8(A)) of these openings 251A is set to 10'' 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 35-size vertical size (2
57 mm) and A4 size vertical size (297 mm), for example, the length Qll is set to approximately 295 mm. The opening 251B accommodates 84-size vertical size (364-size) originals.
11111), for example, approximately 360 mm.
is set to .

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

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.

Like the flange 242, the one flange 252 is rotatably supported on the outer peripheral surface of the suction connection pipe 236 via a bearing BR5.

The boss portion of the other flange 253 is fitted into the seventh flange 243 via a bearing BR6 and is rotatably supported. A drive shaft 254 is fixed to the boss portion of the flange 253. The drive shaft 254 passes freely through the boss portion of the seven 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.

Further, the cam plate 255
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.

A ventilation means 270 is provided on the back side of the document stopper 208.
is provided. The blowing means 270 has a blowing pipe 272 that is long in the paper width direction, and a blowing fan and a motor are attached to one end of the blowing pipe 272 (see FIG. 8(A)).

Below the blow pipe 272, on the side facing the outermost pipe member 231, a blow port 271 consisting of a plurality of small diameter holes is arranged. The air flow generated by the motor and the air blowing fan passes through the air pipe 272 and is blown onto the surface of the outermost tube member 231 from the plurality of air outlets 271 .

At the start of suction feeding, the leading edges of multiple sheets of paper that are about to be suctioned onto the surface of the outermost tube member 231 are separated by the air flow sent between the sheets by this blast, and only one sheet of paper is placed at the top. It is adsorbed to the surface of the outer tube member 231.

Next, we will explain the operation of the circulating document feeder (RDH) equipped with the paper feeding device according to the present invention, the components shown in FIGS. 7(A) and (B), and the suction 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. In this state, the opening 251A of the innermost tube member 251 and the middle tube member 2
As shown in FIG. 8(A), the opening 241A of 41 is held at a relative opening angle θ1 (0'' to 30') and stopped.

■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, is moved forward in the paper feeding direction, and the lower end roller 213, which is pivoted on the lower stage moving body, is moved forward in the paper feeding direction. The roller 216 is moved rearward 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 tray, and when it is detected that the leading edge of the document tray hits the document stopper 208, the control means 219 acts. Drive source M4 stops. (See Figure 7). At this time, the vicinity of the leading edge of the document bundle overhangs due to the contact position with the outermost tube member 231, and is not supported in any way and is kept in a state of being overhanged by the stiffness of the paper.
; (See Figure 8(A)).

(2) Next, the suction means of the suction cylinder device 23.0 is turned on, and the negative pressure suction from the suction source passes through the tube to the suction pipe 235 and the suction connection pipe 236 to create a negative pressure inside the innermost tube member 251. At the same time, the blowing means 270 is also turned on, and pressurized air is blown out from the blowing port 271 and the suction cylinder device 2
It is sprayed toward the outer peripheral surface of the outermost tube member 231 of No. 30. At this time, the outermost tube member 2311, the intermediate tube member 2411, and the innermost tube member 251 are all stopped, and the opening 241A
, 251A is the relative aperture angle θ1 as shown in FIG. 8(A).
Since it is in the intake state by forming the through opening of
The vicinity of the leading end of the original sheet DI is attracted by the negative pressure air passing through the relative opening θl, is separated from the original bundle, and is brought into close contact with the outer peripheral surface of the outermost tube member 231. At this time, the sagging leading end of the paper bundle is blown by the air flow from the air blowing means 270 and is sent between the sheets, so that the separation performance is improved without causing the sheets to be dragged. In this contradictory suction and close contact state, the device waits until paper feeding starts (Fig. 9 (■)).

(2) Subsequently, the intermediate tube member 241 is driven and rotated by the motor M2, the opening 241A rotates clockwise, and the relative opening angle θ2 formed by the opening 251A of the innermost tube member 251 in the stopped state is It is gradually expanded and the aperture ratio increases (see FIG. 8(C)). 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 Di among the document bundles to the opening 251A.

241A and the small diameter through hole 231A to be separated by suction and adsorbed to the circumferential surface of the outermost tube member 231 (the ninth
Figure ■).

■The intermediate tube member 241 is further driven to rotate, and the opening 241
Fully open state where A and 251A coincide, 1 (Fig. 8 (C),
Relative quantity b angle θ2. When the aperture ratio reaches 100%, the original document Dl passes through the openings 251A, 241A and the small diameter through hole 2.
It is sucked in by the negative pressure air passing through 31A and is brought into close contact with the outer peripheral surface of the outermost tube member 231 (FIG. 9O).

■This state (intermediate pipe member 351 stopped, relative opening ratio 100)
%, during intake) for a certain period of time (approximately 30 to 100 m5) (maintains 0 in Figure 9). Due to this continuous suction of only negative pressure for a certain period of time, even if there is a document Di that follows the rotation of the intermediate tube member 241 and is not peeled off and does not come into close contact with the surface of the outermost tube member 231, it is possible to maintain the fully open state in this stopped state. Due to the slit and continuous suction, it is reliably suctioned and brought into close contact with the outer peripheral surface of the outermost tube member 231 (FIG. 9O).

(2) 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 document DI closely adsorbed to the synthetic rubber coating surface of the outer circumferential surface of the outermost tube member 231 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. (FIG. 9O) When the leading edge of the original Di advances along the inner surface of the guide plate 263 and the leading edge detection sensor 264 detects passage of the leading edge of the original, the signal causes the motor M2 to be activated as shown in FIG. 8(D). The intermediate tube member 241 starts to drive and rotate, and the relative opening angle (opening ratio) with respect to the fixed innermost tube member 241 gradually decreases. at the same time,
At the same time as stopping the drive of the motor Ml, the clutch K is turned to O.
FF, and the outermost tube member 231 is driven to rotate (9th
Figure 0). Further, by stopping the drive of the motor Ml, the rotation of the intermediate conveyance roller g61.262 is temporarily stopped via the clutch. After the intermediate conveyance rollers 261 and 262 rotate inertia, they stop with the leading edge of the document being held in the nip position and wait for timing with the transfer paper by the registration rollers of the paper feed device in the copying machine main body 100. .

■ Transfer paper timing In response to the paper feed start signal, the intermediate conveyance rollers 261 and 262 begin to rotate again, and the leading edge of the document Dl is moved between the conveyance belt 220 and the platen glass 1 shown in FIG.
Transfer to the pressure contact position of 02. During this conveyance, the outermost tube member 231 is rotated by the document feed. Further, the intermediate tube member 241 is rotated clockwise as indicated by the arrow, reaches the initial position of the closed state where the relative opening angle is zero, and stops (9th
(!!■).

■Thus, the i-sheet originals DI sent out by the suction cylinder device 230 go forward w! A, the sheet is nipped by intermediate conveyance rollers 261 and 262 provided on the way, and conveyed toward the platen glass 102 and the conveyance belt 220 at a synchronous exposure speed.

■The document DI transported by the intermediate transport rollers 261 and 262 is transported by the transport belt 220 over the grating glass 102 at a synchronous exposure speed, and is exposed to light by a fixed optical system 11O to form an image on the photoreceptor drum. do.

■ After the exposure process, the original D1 moves upward along the paper ejection guide plate 225, and is moved to the original stacker 2 by the paper ejection belt 212.
It will be discharged towards 01. Ejected original D
1 is stacked again with its front and rear ends aligned by the document stopper 208 and the trailing edge regulating plate 202, and its width aligned by the width regulating plates 203, 203. Further, the document stack placed earlier and the circulated document Dl are sorted by the device 210. The above-mentioned feeding operation is repeated until there is no remaining document on the document stacker 201.

Then, the stack sensor 20
When it is detected in step 6 that the last original has been ejected by the paper ejection sensor, the stacked original is sent out by the trailing edge regulating plate 202, and the above operation is repeated until the set number of copies is completed. 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 when a one-sided original is copied on one side in the RD)l mode. Further, when a cylindrical 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.

The suction cylinder device 230 and the air blowing means 270 having a triple tube structure according to the present invention are effective when applied to a document conveying device that feeds the document from the bottom, but can also be applied to a paper feeding device that feeds the paper from the bottom. It is.

〔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 document is sent out and separated and fed by the triple tube structure and the suction cylinder device and the air blowing means, which are separated from the suction means, there is no need to press the stacked documents, and the front and back sides of the documents are separated. is caused by friction
It is possible to prevent image disturbances due to dirt, scratches, etc. on the front and back surfaces. 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]

1 is a front sectional view of a document conveying device showing an embodiment of a paper feeder according to the present invention, FIG. 2 is a partially sectional plan view of a triple tube machine tank of the device shown in FIG. 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 expanded plan view of the third cylinder and document size, and FIG. Figures (A), (B'
) is a configuration diagram of the circulating document conveyance device, and Figures 8(A) to (E
) is a sectional view illustrating the paper feeding process of the paper feeding device, and FIG. 9 is a time chart of the paper feeding process. 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) 201A...
・Front end portion 202... Rear end regulation plate 203...
- Width regulation plate 207...Original set detection sensor 208...Original stopper 210...Original classification is done by device (set separator) 21
2... Paper ejection belt 220... Conveyance belt 230...
・Vacuum feeding means (suction cylinder device) 231... Outermost tube member (first cylinder) 241... Intermediate tube member (second cylinder)
cylinder) 251... Innermost pipe member (third cylinder) 2
31A...Small diameter through hole 235...Suction pipe 23
6... Suction connection pipe 241A... Opening 251
A, 251B, 251G...Opening 261.262.
・Intermediate conveyance roller 263 ・Guide plate 264 ・Document leading edge detection sensor 270 ・Blower means 271 ・Blower port 27
2...Blow pipe θl, θ2...Relative opening angle, DI...Manuscript

Claims (1)

[Claims] 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 paper stack, a pipe-shaped cylindrical body is provided below near the front end of the paper stack in the feeding direction. a drive rotatable outer cylinder with a large number of small openings bored on the circumferential surface thereof; at least one inner cylinder disposed inside the outer cylinder and having a slit-like opening on the circumferential surface of a pipe-shaped cylindrical body; A suction device connected to the inner cylinder is provided with a vacuum feeding means for suctioning and transporting the lowest layer of paper in the paper stack, and also applies pressure to the surface of the outer cylinder and near the front end of the paper stack. 1. A paper feeding device comprising a blower configured to eject air to separate the lowest sheet of a paper stack from the rest of the paper stack.