JPH06211406A - Automatic document conveying device - Google Patents

Abstract

PURPOSE:To provide an automatic document conveying device which can recirculate return documents a by placing them in line percisely on a document placing position by stabilizing circulation movement of the documents certainly, and also preventing interference between the documents so as to enable high speed transport of documents and can improve accuracy of document stopping position on the document placing position. CONSTITUTION:An automatic document conveying device is set in a document inversion discharge mode, where a document is discharged to a document placing position 310 or a paper sheet discharge tray 360, after the conveying direction of the document is inverted in such a way that the rear edge in the running direction of the document D, which is carried out from a picture image reading section 111 of a copying machine to a discharge section 350, becomes the front edge in the discharging direction of the document. At this time, the conveying speed V2 of a paper sheet discharge roller 355 (352) which is provided near discharge end point of the discharge section 350 intil the document is pulled out, is set to be switched from high speed V1 to low speed V2, in relation to the conveying speed V1 to finish carrying out of the document from the picture image reading section 111.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a recording device such as an electrophotographic copying machine or an automatic document feeder attached to an image reading device, and more particularly to a single-sided or double-sided recording mounted on a document placing portion. ADF mode and R-ADF mode, in which documents are separated and fed one by one to the image reading unit and the read documents are ejected to the paper ejection tray, especially after the documents have been read are returned to the document stacking unit and repeatedly fed. The present invention relates to an automatic document feeder having a single-sided document circulation transport mode (RDH mode) and a double-sided document reversal circulation transport mode (R-RDH mode) which are capable of making paper.

[0002]

BACKGROUND OF THE INVENTION As a device capable of efficiently feeding an image-recorded document to a recording device such as an electrophotographic copying machine or a recorded image reading device, even in an unmanned state, an automated document conveying device ( ADF) has already been provided.

Further, as a copying machine capable of copying each image of an original (double-sided original) having recorded images on the front and back sides and one side or both sides of the recording paper, and an image reading device capable of reading and recording the images, the ADF is provided with front and back sides of the original. An automatic document feeder (R-ADF device) having a reversing function has been put into practical use.

Further, the originals stacked on the original placing portion are separated one by one and automatically fed on the platen glass of the copying machine, and the originals after the exposure processing on the platen glass are again placed on the original placing portion. A circulating automatic document feeder (RDH device) that can be returned and repeatedly processed has also been proposed.

This circulation type automatic document feeder (RDH device) makes copies one by one in one cycle and circulates the originals by the number of copies.

Further, recently, the present applicant has also provided a circulation type automatic document feeder (R-RDH device) in which a document front / back surface reversing mechanism is added to the RDH device (Japanese Patent Application No. 63-202).
No. 28 and others).

These circulating automatic document feeders (RDH,
R-RDH (hereinafter referred to as RDH device) enables high-speed continuous copying and quick page alignment of copied recording paper, and is connected to a finisher device for stapling and punching the recording paper for final processing of the recording paper. Can be completed unattended.

In such an RDH apparatus, a plurality of originals, which are stacked with the front side of the originals facing upward on the original placing section, are fed one by one from the lowermost layer to the processing section (platen glass surface) in the feeding section. It is a bottom feed top return system that separates and conveys toward the bottom.

In such a bottom feed top return type RDH device, when the documents are fed out, problems such as the disorder of the document image due to the smearing or rubbing of the document front and back surfaces caused by the friction between the document front and back surfaces occur. In particular, in the case of a pencil-written manuscript, the manuscript stains due to the above problems are remarkable.

As a means for solving the above problem, Japanese Patent Publication No. 56
The top feed / bottom restack type RDH device disclosed in Japanese Patent No. 37536 has been proposed. In this method, the processed sheet is inserted from the lower side of the stack sheet by the cyclically moving stack lifting means for lifting the sheet.

In these RDH devices, since the originals after the image reading processing are circulated, placed on the original placing portion and re-fed, the originals ejected from the paper ejecting means are aligned and placed accurately. There is a need. Further, even in the ADF and R-ADF modes, the sheets are unevenly ejected onto the sheet ejection tray, causing problems such as documents being scattered or popping out of the tray and falling.

As an example disclosed as a measure for discharging a document in a conventional automatic document feeder, Japanese Patent Laid-Open No. 4-14
No. 0280, JP-A-4-164786, JP-A-4-164787, and the specification of Japanese Patent Application No. 2-403220 by the present applicant are mentioned.

[0013]

Since the amount of movement of the original is small when the speed of discharging the original is relatively low, the originals are not aligned or misaligned when the original is discharged. Accurate contact with the leading edge stopper on the document placing portion does not stop and overruns, causing problems such as deformation of the leading edge of the document, rebounding of the document, and undelivering of the document. Further, in the ADF mode and the R-ADF mode, the paper often jumps out from the paper discharge tray or scatters.

In particular, in a copying machine capable of high-speed processing, in which a plurality of originals are brought close to each other on the image reading section (platen glass) and sequentially fed to improve copy productivity, the preceding originals conveyed by the conveying means are discharged at a low speed. In this case, the conveyance of the subsequent document to the image reading position, which proceeds at the same speed, is delayed and the document replacement time is increased. Further, if only the discharging speed of the preceding document is slowed, the succeeding document tracks the preceding document and approaches, and the trailing edge of the preceding document and the leading edge of the following document collide with each other, resulting in conveyance failure.

In particular, in the R-ADF mode or the R-RDH mode, the exposed document discharged from the image reading unit (platen glass) is switched back and turned upside down and placed on the document placing unit or the discharge tray. Need to be placed on.

In order to make the automatic document feeder a thin and compact structure, the U of the document front / back reversing path of the paper discharge section is used.
Turn paths and S-shaped paths must have a small radius of curvature. When an inverted document is conveyed at a high speed through such a curved path, there are problems such as a conveyance failure in the path and unevenness of the discharged document.

[0017]

SUMMARY OF THE INVENTION The present invention solves various problems in the conventional automatic document feeder as described above, and stabilizes the R-ADF mode and the R-ADF mode even during a high-speed feeding operation.
An object of the present invention is to provide an automatic document feeder having an RDH mode.

In particular, an object of the present invention is to reduce the time required for conveying a plurality of originals from the image reading section by minimizing the conveying distance between the preceding original and the succeeding original with a simple structure and control. Another object of the present invention is to provide an automatic document feeder capable of shortening the copying time by shortening the sheet feeding time and eliminating the conveyance failure of the sheet discharge section and the unevenness of the discharged sheet documents. Further, another object of the present invention is to provide a thin and compact automatic document feeder.

In the automatic document feeder of the present invention which achieves the above object, one of a plurality of documents stacked on the document placing section is separated and fed to the image reading section. A feeding unit, a feeding unit that feeds the document fed to the image reading unit and stops the document at a predetermined image reading position, and then carries out the document after the image reading, and a feeding unit downstream from the image reading unit in the feeding direction. In an automatic document feeder that includes a discharge unit that discharges a document that is positioned and conveyed from the conveyance unit to the document placement unit or a discharge tray outside the machine, the progress of the document that is conveyed from the image reading unit to the discharge unit When the document reverse direction is set so that the document transport direction is reversed so that the trailing edge in the direction of the document is the front edge in the document ejection direction, and the document is ejected to the document placing section or the paper ejection tray, the document is read from the image reading section. Transport speed V1 until the delivery is completed To, the conveying speed V to the document discharge roller provided near the discharge end position of the discharge portion escapes
2 is set so as to be switched to a low speed.

[0020]

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

FIG. 1 is an overall configuration diagram of a copying machine equipped with an automatic document feeder. 100 is a copying machine main body, 200 is a paper feeding unit (PFU device), and 300 is a circulation type automatic document feeder (RDH device). ), 400 is a copying paper post-processing device (finisher (sorter with stapler device, etc.) hereafter referred to as FNS device).

The copying machine main body 100 includes a scanning exposure section 110, an image forming section 120, a sheet feeding section 130, a conveying section 140, a fixing section 150, a sheet discharge switching section 160, a plurality of sheet feeding cassettes 170, and copy sheets for double-sided copying. It is composed of a re-feeding device (ADU device) 180.

In the figure, the alternate long and short dash line indicates the conveyance path of the copy paper P. After the copy paper P stored in the paper feed cassette 170 or the paper feed unit (PFU) 200 at the bottom of the copying machine main body 100 is image-formed by the image forming unit 120, the transport unit 140, the fixing unit 150, and the paper discharge unit. The main route accommodated in the FNS device 400 via the switching unit 160 and the copy paper P branched from the paper discharge switching unit 160 are temporarily stocked in the ADU device 180, and then re-fed to the copying machine main body 100. The circulation route to the paper feeding unit 130.

FIG. 2 is a sectional view of the automatic document feeder 300 mounted on the upper portion of the copying machine main body 100. The automatic document feeder 300 to which the present invention is applicable conveys a plurality of originals (single-sided original or double-sided original) from the original placing section 310 to the exposure section of the platen glass 111 of the copying machine main body 100,
It is provided with various functions such as a circulation type RDH device, an R-RDH device, an ADF device, an R-ADF device, etc., which conveys again onto the document placing section 310.

The automatic document feeder 300 includes a document placing section 310,
Feeding unit 320, intermediate conveying unit 330, conveying unit 340, paper discharge reversing unit 350
It consists of

When the document stack D is placed on the document placing section 310, the presence or absence of the document is detected by the document set detection sensor (zero document detection sensor) S1, and the ADF mode is displayed on the control panel of the copying machine main body 100. Is displayed. When the document stack D is set at a predetermined position, the document size (B5 to A3) is detected by the document size sensor S2 and input to the control unit of the copying machine main body 100.

A movable pressing plate 317 can be swung about a swing shaft 317A on the leading end side of the document feeding portion 310 on the downstream side of feeding the document. A drive plate 319 is screwed to the swing shaft 317A so that it can swing integrally. Further, an elastically deformable member (for example, a torsion spring) 317 is attached to the swing shaft 317A.
B is wound, and the drive plate 319 can be pressed at both ends thereof and the movable pressing plate 317 can be pressed at the center thereof.

The actuator portion provided on the drive plate 319 has a pressing home position sensor S fixed to a fixed bottom plate.
The optical path of 3 is turned on and off, and the home position of the drive plate 319 is detected.

FIG. 3 is a perspective view of an essential part of the document placing section 310. The wide feeding belt 311 which is loaded with the document D and supported and is rotatable is an endless belt wound around two axes of a driving roller 312A and a driven roller 312B.

FIG. 4 shows a perspective view of the feeding belt 311. One end of the feeding belt 311 is joined by a joint 311A to form a loop. The other end of the belt 311 forms a tongue-shaped holding piece portion (gripper portion) 311B extending outward from the seam portion 311A. The feeding belt 311 is formed of a cloth belt coated with resin, a polyethylene terephthalate (PET) film, or the like. The inner surface of the sandwiching piece 311B of the feeding belt 311 and the outer surface of the belt (between A and B in FIG. 4) are roughened so as to have a high friction coefficient, and the other outer surface of the belt (B in FIG. 4). (Between C and C) forms a low friction coefficient smooth surface. 31
Reference numeral 1C is a detection hole formed in a part of the belt 311, and the home position of the feeding belt 311 is detected by the reflection type sensor S13 for detecting the home position of the feeding belt 311. The stop position of the sandwiching piece 311B is controlled.

In FIG. 3, a discharge brake BRK2 connected to a discharge motor M3 as a drive source and an electromagnetic clutch CL4 are provided at the rotary shaft end of the drive roller 312A. A fixed plate 313 is fixedly provided inside the feeding belt 311 between the drive roller 312A and the driven roller 312B. The fixed plate
313 supports the document bundle D on the feeding belt 311 by placing it on a flat surface.

Denoting means 315 separates the lowermost sheet of the original bundle stacked on the feeding belt 311 from the uppermost sheet of the original bundle that is circulated and conveyed after the reading process to be bottomed on the lowermost layer of the stacked original bundle. Is. The separating lever 315A of the separating means 315 is spring-biased, and the solenoids SL3, S
L4 is used for ascending / descending, forward / backward driving in a direction orthogonal to the sheet feeding, and obliquely ascending / descending driving.

In 311D, the separating lever 315A is a feeding belt.
Feed belt 3 to allow to rise above 311
It is a notch provided on the side of 11.

The original stack placed on the original placing section 310 is stacked on the feeding belt 311 and a movable pressing plate 317 which will be described later, and the width stopper plate 316 for restricting the original width in the original width direction on the basis of one side. At the same time, the leading edge of the original is brought into contact with an original leading end stopper 318, which will be described later, and aligned and placed. At this time, the separating lever 315A is pressed and lowered by the weight of the document stack, and lightly pushes up the lowermost layer of the document stack. Further, the swingable paper pressing lever 310Z provided on the upstream side of the separating lever 315A in the document conveying direction is for assisting the returning document to be surely inserted under the document stack, and the document surface is supported by its own weight. Lightly press. The paper pressing lever 310Z is also effective for stabilizing the operation of the separating lever 315A when carrying curled paper or a small number of originals.

FIG. 5 is a front sectional view of the document placing portion 310 and the feeding portion 320, and FIG. 6 is a side view of the separating means 315 and the separating lever pushing means (hereinafter referred to as pushing means) 314. In these figures, a separating means 315 and a pushing-up means 314 are fixedly provided on one fixed side plate that pivotally supports a driving roller 312A and a driven roller 312B that rotate the feeding belt 311.
That is, the pushing means 314 is fixed near the one side end of the feeding belt 311 on the upstream side in the conveying direction, and the separating means 315 is fixed on the downstream side in the arrow direction.

A solenoid SL3 is fixed to the lower portion of the board 315B of the separating means 315, and the solenoid SL3 is fixed.
The lower end of the swing lever 315C is pin-connected to one end of the plunger SL3A. The swing lever 315C is provided on the substrate 3
It can swing around a fulcrum shaft 315D planted in 15B and is urged in one direction by a spring 315E. The upper end of the swing lever 315C has a separating lever 315A and a pin 315F.
Are bound by. Separation lever 315A has pin 315F
The weight 31 that can be swung around is fixed to the left end.
Due to the 5G's own weight, the left end part hangs down and can be tilted when no regulatory force is applied.

A pin 315H is provided in the middle of the separating lever 315A.
And is movable along the wall surface of the D-shaped cam groove portion 315J formed in the substrate 315B. 315K is a boat-shaped leaf spring attached to the base plate 315B, and is in sliding contact with the upper surface of the separating lever 315A to form a separating lever 315A.
Will be the guide surface for horizontal movement.

A solenoid SL4 is fixed to the lower part of the base plate 314B of the separating lever pushing up means 314, and a swing lever 314 is provided at one end of a plunger SL4A of the solenoid SL4.
One end of C is pin-connected. The swing lever 314C is swingable around a fulcrum shaft 314D planted on the upper portion of the substrate 314B, and is biased in one direction by a spring. The other end of the rocking lever 314C is provided with a long rod-shaped push-up lever 3
The base of 14A is driven in and the tip projects. The push-up lever 314A is in contact with the lower surface of the separating lever 315A in the vicinity of the front end thereof and is held so as to be able to move up and down.

In the initial no-load state in which the original stack is not placed on the feeding belt 311 of the original placing portion 310, the separating lever 315A is tilted by the weight of the weight 315G and the right end portion is raised. It has become (position of Figure 6). Then, the pin 315H reaches the top dead center of the cam groove portion 315J and is positionally regulated and stopped. At the raised position of the separating lever 315A, the copy number separating sensor S14 is turned off.

When a bundle of documents D is stacked on the feeding belt 311 of the document placing portion 310 and the leading end of the separating lever 315A is lowered by the weight of the document stack D, the pin 315H of the separating lever 315A has a cam groove portion. It descends along 315J and is lightly pressed against the bottom sheet of the document stack (position shown in the figure). In this descending state of the separating lever 315A, the copy number separating sensor S14 is turned on. At this time, the front end of the paper pressing lever 310Z presses the upper surface of the document stack by its own weight.

As the document stack on the document stacking section 310 is fed upward and returned to the bottom, the leading end of the separating lever 315A is sandwiched between the last page of the stack of document stacks and the first page of the returned document. As the number of return originals increases, the return originals gradually rise (position shown), and when the first page of the return original reaches the uppermost portion, it becomes free and jumps up into the upper space (position shown). At this time, the copy number sensor S14 is turned off.

The separating lever 315A is a solenoid SL.
The suction operation of 3 draws it to the left in the drawing (the position shown). When a voltage is applied to the solenoid SL3, the plunger SL3A is attracted and the swing lever 315C is swung in the counterclockwise direction indicated by the arrow about the fulcrum shaft 315D, and the pin 3
The separator lever 315A connected by 15F is moved to the left. The pin 315H implanted in the separating lever 315A is
It moves diagonally downward in the cam groove 315J, and the cam groove 315J
Stops the movement by contacting the left end of the. At this time, the leaf spring 315
K slides on the upper surface of the separating lever 315A to prevent the separating lever 315A from jumping upward.

When the energization of the solenoid SL3 is turned off after a predetermined time, the rocking lever 315C is supported by the spring 315E as a fulcrum 31.
Rotate clockwise around 5D to move the lever 315A to the right (position shown in the figure). At this time, leaf spring 315K
Keeps the lever 315A horizontally, the pin 315H
The sheet moves to the right and the leading end of the cutout portion 311D of the sheet feeding belt 311 enters and rises by its own weight to rotate and come into contact with the lower surface of the original.

A notch 311D is formed at one end of the feeding belt 311 so that the separating lever 315A can be retracted below the feeding belt 311. When the document bundle is stacked on the feeding belt 311 and rotated, the cutout portion 311D may collide with the lower layer of the document bundle to cause conveyance failure. To prevent this, before the cutout portion 311D passes upstream of the document stack in the document transport direction, one end of the document stack is pushed upward so as not to interfere with the feeding belt 311 and at the same time, the document is separated. Make sure that the tip of the lever 315A is returned and that it is inserted above the document. In other words, when the first document after the exposure processing is discharged and returned to the bottom of the document stack on the feeding belt 311 of the document placing section 310, the nip portion 311B of the rotating feeding belt 311 is used. Leading notch 31
The separating lever 315A is always located above 1D, and the separating lever 315A is raised by a predetermined amount so that the separating lever 315A is surely located above the feeding belt 311, and the relevant portion of the document stack is retracted upward. deep. Therefore, the solenoid SL4 is actuated by the signal for document replacement, and the plunger S
L4A is sucked, the swing lever 314C is swung about the fulcrum shaft 314D, and the push-up lever 314A is raised. When the push-up lever 314A swings, the corresponding separation lever 315A is lifted upward by a predetermined amount and stopped. As a result, one end of the document stack of the separating lever 315A is lifted upward so that it can pass through the cutout portion 311D of the feeding belt 311. At the same time, it will surely return and separate the document
Guide below 315A.

As shown in FIGS. 2 and 3, on the downstream side of the feeding belt 311 in the document feeding direction, movable pressing plates 317 of movable pressing means are provided on both side plates integrally formed with the fixed bottom plate 310A. A drive plate 319 is screwed to a swing shaft 317A supported by a bearing so that it can swing integrally. An elastically deformable member (for example, a torsion spring) 317B is wound around the swing shaft 317A, and both ends of the elastically deformable member 317B are pressed against the drive plate 319 and the movable pressing plate 317 to bias the spring.
At this time, the movable pressing plate 317 and the drive plate 319 are pushed in the opening direction of the torsion spring 317B, but the lower end portion of the movable pressing plate 317 abuts one end of the drive plate 319 and the opening angle between them is a certain amount or more. It is regulated not to open. The spring pressure of the torsion spring 317B is adjusted to the set pressure.

An actuator portion (light shielding plate portion) 319A projects from one end of the swing shaft 317A. The actuator portion 319A includes a pressing home position sensor (for example, a photo interrupter) S3 fixed to the fixed bottom plate 310A.
The optical position of the drive plate 319 is turned on and off, and the home position of the drive plate 319 is detected. It can swing around the swing shaft 317A. A gear is fixed to one shaft end of the swing shaft 317A and is connected to the gear fixed to the drive shaft of the pressing motor M1.

A document end stopper 318 is fixed to the main body of the automatic document feeder near the leading end of the movable pressing plate 317 on the downstream side of document feeding.

Above the movable pressing plate 317, a feeding section 320 is provided.
Is provided. The feeding unit 320 includes a feeding roller 321.
A driving roller 322, a driven roller 323, a feed belt 324 that winds and rotates both rollers, and a double feed preventing reverse roller 325 located below the feed belt 324. The driving force of the driving motor M2 is transmitted to the driving roller 322 via the electromagnetic clutch CL1.

Frame body 321 holding the delivery roller 321
A is swingable around a support shaft A. The frame 321A
The actuator part 321 protruding at the tip of the
B is integrally formed and turns on / off the detection optical path of the pressure detection sensor S4 fixed at a predetermined position of the fixed stay member 300A of the automatic document feeder 300.

FIG. 7 is a schematic view showing the state of conveyance of the document D discharged from the sheet discharge reversing section 350 to the feeding belt 311 of the document placing section 310 and the movable pressing plate 317.

After a lapse of a predetermined time (the leading edge of the original comes near the sandwiching piece portion 311B) after the leading edge of the original D1 is detected by the paper discharge sensor S9, the clutch is engaged, and the feeding belt 311 starts rotating from the home position. When the leading end of the document D is clamped by the clamping piece 311B, the document D is clamped on the rough surface of the feeding belt 311 which is further rotated, and is inserted into the lowermost layer of the stacked unprocessed document D to be illustrated. Carried to the left (Fig. 7 (A),
(See (B)). As described above, at this time, the separating lever 315
A is a lifting lever 314A via a solenoid SL4
Then, it is lifted up through the cutout portion 311D of the paper feed belt 311 to raise the document stack by a predetermined amount.

At this time, the movable pressing plate 317 is in the lowered position, and the leading end of the document stack D is separated from the feeding roller 321. The surface linear velocity of the feeding belt 311 is set to be slightly higher than or equal to the surface linear velocity of the circulation paper ejection roller (deviation correction roller) 355 of the paper ejection reversing unit 350 (for example, roller speed 1000 mm / sec. To about 1150 mm / sec). Further, since the surface of the feeding belt 311 that comes into contact with the document D is a rough surface, the document D is reliably held by the feeding belt 311 and fed.

Further, since the surface of the feeding belt 311 contacting the lowermost layer of the document stack D is a smooth surface, the feeding belt 311 smoothly rotates in sliding contact with the lower surface of the document stack.

Document D held on the feeding belt 311
Is slid on the upper surface of the movable pressing plate 317 slightly below the upper surface of the feeding belt 311 as the feeding belt 311 is turned downward along the driven roller 312B, and hits the document leading edge stopper 318. , Feeding stops. Therefore, if the total rough surface circumference of the feeding belt 311 is set to be equal to or greater than the maximum length of the document D being circulated and conveyed in the feeding direction, the document returning operation is good.

Referring again to FIG. 2, an intermediate conveying section 330 is provided on the downstream side of the original conveying with respect to the feeding section 320. The intermediate conveying section 330 includes a first intermediate conveying roller pair 3 which is driven to rotate forward.
31, a curved guide plate 332, and a pair of second intermediate conveying rollers 334 form a conveying path for conveying the document D sent from the feeding unit 320 to one end of the platen glass 111.

A reversing means is provided on the left side of the second intermediate conveying roller pair 334 and on the left side of the platen glass 111 in the drawing. The pair of reverse conveyance rollers 335 is always driven to rotate normally by the one-way clutch CL5. A curved guide plate 336 connects the nip positions of the second intermediate conveyance roller pair 334 and the reverse conveyance roller pair 335, and forms a document reverse feed path. A reversal detection sensor is provided in a part of the reversal feed path, and detects passage of a reversal fed document.

On the surface of the platen glass 111, a conveyor belt 341 is rotatably stretched between a driving roller 342, a driven roller 343, four document pressing rollers 344 and a tension roller 345. A clutch and a brake are rotatably supported on the shaft of the drive roller 342.
Is operated by the driving force of the drive motor M2.

The paper output reversing section 350 includes paper output rollers 351, 352,
The switching claws 353 and 357, the reversal paper discharge roller 354, the circulation paper discharge roller 355, and the guide plates 356A, 356B and 356C are included. Paper ejection rollers 351, 352, reverse paper ejection roller 35
4. The circulation paper discharge roller 355 is driven by the paper discharge motor M3. The paper discharge rollers 352 and the circulation paper discharge rollers 355 are driven in the forward direction by a paper discharge motor M3, and the paper discharge rollers 351 and 354 are driven.
Is normally and reversely driven, and the discharge rollers 355 and 352 are always normally and normally driven. The switching claw 353 is driven by the switching solenoid SL1. The switching claw 357 is driven by the switching solenoid SL2.

On the upper part of the copying machine main body 100, a discharge tray section 360 is fixedly installed near the discharge opening of the discharge reversing section 350 of the automatic document feeder 300. The paper output tray unit 360 is
A fixed tray 361 having an inclined surface fixed to the upper surface of the casing of the copying machine main body 100 by a screw or the like, and a movable tray (a resin tray) pivotally supported by a fulcrum shaft 362 provided at one end of the fixed tray 361. ) And 363. In the folded state of the movable tray 363, a reverse discharge path 364 is formed between the inclined upper surface of the fixed tray 361 and the inclined lower surface of the movable tray 363 with a constant space. The document D sent from the reversing and discharging roller 354 is moved up the reversing and discharging path 364, the sensor S11 detects the trailing edge of the document, and after a predetermined period of time, the document D is temporarily stopped, and then the reversing and discharging roller 354 is operated. By reverse rotation drive, it is introduced into the automatic document feeder 300,
In the R-ADF mode of a double-sided original, it is ejected to the outside of the machine by the paper ejection roller 352 of the paper ejection reversing unit 350 through the guide 356C and placed on the upper surface of the movable tray 363.

When the movable tray 363 of the paper discharge tray section 360 is rotated and unfolded,
Large originals such as A2 size paper and fanfold paper (CFF) can be discharged to the lower surface side of the movable tray 363.

In addition, the reverse circulation mode (RR
At the time of (DH), the switching claw 357 is switched downward, and the document D conveyed to the reversal paper ejection path 364 is placed on the document through the reversal paper ejection roller 354, the guide plates 356C and 356B, and the circulation paper ejection roller 355. Returned to part 310.

FIG. 8 and FIG. 9 are schematic diagrams showing the document conveyance path (dotted line) in various modes.

FIG. 8A shows an ADF mode in which a single-sided original is copied and discharged to the discharge tray section 360 outside the machine. The original D is fed from the original placing section 310 to paths a, b, c and d. , E,
After f, g, and h, in the case of a general document of A3 size or less, it is placed and accommodated on the movable tray 363. Large size manuscript (A
In the case of 2, A3, 11 × 17 inch paper, etc.), the fixed tray 361 and the movable tray 363 are placed and accommodated on two surfaces connected to each other.

FIG. 8B shows an R-ADF mode in which a double-sided original is copied and discharged to the paper output tray unit 360 outside the machine. The original D first follows the above-mentioned paths a, b, c, d, and e. After exposing the first surface of the original through the platen glass 111, the platen glass 111 is moved backward and the loop path i is turned upside down to pass through the path d again. Perform exposure processing. The document D that has been subjected to double-sided exposure processing is carried out to the paper discharge reversing unit 350, and the front end of the document passes through the paths j and k, and the tunnel-shaped reverse paper discharge passage 3 of the paper discharge tray unit 360.
When the trailing edge of the document is detected by the sensor S11 after entering the sheet 64, the conveyance is temporarily stopped, but the trailing edge of the document is nipped by the reverse discharge roller 354, and then the document is reversed by the reverse rotation of the roller 354. The paper is sent and turned upside down through the path m, is nipped by the paper discharge roller 352, is discharged in the direction of the path h, and is placed and accommodated on the movable tray 363 of the paper discharge tray unit 360. At this time, the carry-in speed to the discharge reversal unit 350 is set to V1 at a high speed, and after temporarily stopping, the document D is conveyed at a low speed V2 at the time of reverse feeding.

FIG. 9C is a schematic diagram of the RDH mode showing the circulation circulation of a single-sided original and a single-sided copy. The one-sided original D is passed through the sequential circulation paths a, b, c, d, and e, and after the exposure processing, is passed through the paths f, g, and n of the sheet discharge reversing unit 350, and the feeding belt 311 of the original placing unit 310 is clamped. The sheet enters the one-sided portion 311B, is conveyed by the feeding belt 311, and is returned to the bottom layer of the original stack.

FIG. 9D is a schematic view of the R-RDH mode showing the document circulation conveyance during double-sided copy and double-sided copy. The path to the exposure process for the odd-numbered side of a two-sided original is
Same as the mode, one side copied sheets are stacked in ADU 180. Further, the original document is sent out again through the paths a, b, c, d, and the original surface is reversed on the path i. Then, the original document D after the exposure process reaches the exposure j, k similarly to the conveyance path in the R-ADF mode. Then, the sheet is switched back and is fed to the original placement portion 310 after being nipped by the sheet discharge roller 355 through the paths m and n with the surface when being sent up. At this time as well, the document D is similarly conveyed to the discharge reversing unit 350 at a high speed V1 and at a low speed V2 at the time of reverse feeding after being temporarily stopped.

FIG. 10 is a block diagram showing the drive system (power transmission system) of the automatic document feeder 300, and FIG. 11 is a block diagram of the drive system. The CPU controls all the operations. Figure 12 shows R
6 is a timing chart of the drive system in the DH mode.

Of the document transport operations in various modes,
First, the single-sided document circulation transport mode (RDH mode) will be described.

(1) Initialization (1A) Turn on the main switch of the copying machine main body 100. When the main switch is turned on, the pressing motor M1 starts to rotate in the reverse direction and the offset correction motor M4 starts to rotate in the normal direction. At the same time, the paper discharge motor M3 and the bottom return clutch CL4 are turned on to start the driving rotation of the driving roller 312A.

(1B) Movable pressure plate home position stop When the main switch is turned on, the pressure motor (stepping motor) M1 is driven in the reverse direction to swing the drive plate 319, and the actuator portion 319A fixed to the swing shaft 317A. When the pressing home position sensor S3 is turned on, the reverse rotation of the pressing motor M1 is stopped by the detection signal,
The drive plate 319 and the movable pressing plate 317 are stopped at the lowest initial position (home position). This is effective in absorbing the time lag of the drive gear and the sensor on. At this home position stop position, a clearance capable of accommodating a predetermined maximum amount of the document bundle D is maintained.

(1C) Placement of Document Bundle When the document bundle D is placed on the feeding belt 311 and the movable pressing plate 317, the set detection sensor S1 is turned on and the ADF mode is set. At the same time, the size detection sensor S2 is turned on to detect the document size. Next, the RDH mode is selected and input.

(1D) Home Position Search Operation of the Offset Correcting Roller The offset correcting roller 355 is movable in the direction orthogonal to the sheet conveyance, and is driven by the offset correcting motor M4 which is driven and rotated by turning on the main switch. . An offset home position sensor S15 for detecting the roller position is provided outside the sheet passage of the offset correction roller 355.

When the main switch is turned on, if the sensor S
If 15 is off, rotate the offset correction motor M4,
When the sensor S15 is turned on by moving the roller 355 in the depth direction, the motor M4 is stopped. The motor M4 is a step motor, and after stopping, a constant voltage is applied to bring it into a hold state. If the sensor S15 is on, the motor M4
Reversely, the roller 355 is moved in the front direction to turn off the sensor S15 once, and then the motor M4 is again rotated forward to stop and hold the motor M4 when the sensor S15 is turned on. By this operation, the motor M4 to the roller 355
The roller 355 always stops at an accurate predetermined position regardless of rattling of gears and the like. This predetermined position is usually adjusted to be substantially at the center of the possible range of the roller 355.

(1E) Bottom Return Feeding Belt Home Position Search Operation The bottom return feeding belt 311 having a nipping piece portion 311B in a part of the driving roller 312A and the driven roller 312B is
As shown in FIGS. 3 and 4, there is a through hole 311C for home position detection. When the main switch turns on,
Turn on the discharge motor M3 and bottom return CL4, and drive roller
Rotate 312A. The drive roller 312A is driven through the one-way rotation clutch CL6 and always rotates in the direction of the solid arrow regardless of the forward / reverse rotation of the motor M4.

When the home position detecting hole 311C on the feeding belt 311 passes through the belt home position sensor S13, the sensor S13 is turned off. After a predetermined time (T1), the paper discharge motor M3 and the bottom return clutch CL4 are turned off. At the same time, the paper ejection brake BRK2 is turned on and the drive roller 31
2 Stop A suddenly. As shown in the figure, the bottom return feeding belt 311 has the sandwiching piece portion 311B on the extension of the offset correction roller pair 355, and the cutout portion 311D is aligned with the position of the separating lever 315A.

(2) Circulation of Original Document By the above initialization operation, the preparation for feeding the original document is completed, and then the original document feeding is started. 14 (A) to (F)
FIG. 6 is a schematic diagram showing a process of conveying a single-sided original.

(2A) When the copy button is turned on, the pressing motor M1, the paper discharge motor M3, the bottom return clutch CL4
Is turned on and document feeding and copying can be started.

(2B) When the copy button is turned on, the bottom return clutch CL4 is turned on to start the low-speed drive rotation of the paper discharge motor M3. As a result, the drive roller 312A is rotated, and the feeding belt 311 is rotated (low speed V2). When the detection hole 311C of the feeding belt 311 passes through the belt home position sensor S13, the detection signal causes the sheet discharge motor M3 to be stopped after a predetermined time (T1), and at the same time, the clutch CL4 is turned off and the brake BRK2 is turned on. Belt 31
1 is stopped and the cutout portion 311D and the sandwiching piece portion 311B are set at the reference positions, and at the same time, the number division solenoid SL3 is turned on, and the division lever 315A contacts the lowermost layer of the original stack through the cutout portion 311D.

(2C) By turning on the copy button,
The pressing motor M1 is driven and rotated, and the movable pressing plate is moved through the drive plate 319 fixed to the swing shaft 317A and the torsion spring 317B.
317 oscillates and rotates, and the leading end of the 317 moves up to lift the stack of originals D. In the ascending process, the swing angle of the swing shaft 317A counts the pulse count C1 by a rotary encoder or the like.

(2D) When the upper surface of the bundle of documents D stacked on the movable pressing plate 317 is lightly pressed against the outer peripheral surface of the delivery roller 321 which is lowered to a predetermined position by its own weight, the movable pressing plate 317 is moved. Feeding roller 321 with the stack of originals sandwiched
Raise. After rising by a predetermined amount, the pressure detection sensor S at the tip
4 is turned on, and counting is started. When it further oscillates, the frame body 321 holding the feed roller 321 comes into contact with a fixing member (not shown) and stops. However, drive plate 319
Is further driven and rotated to rotate counterclockwise while compressing the torsion spring 317B, so that the movable pressing plate 317 and the driving plate 319 are rotated.
The intervals between are getting narrower. When the pressure detection sensor S4 is turned on, the initial set pressure (for example, the roller own weight of 50 g) is reached, and counting of the count C1 is stopped.

(2E) The paper bundle thickness of the original bundle D is detected by the output of the count C1, and the press is predetermined by the original size detected by the size sensor S2 or the setting input of thick paper or thin paper. The designated pulse is determined by the pulse table. The original sheet bundle thickness is detected by the count value of the count C1, and the sheet bundle thickness is set to be divided into, for example, three stages of high, medium and low.

As the original paper size, for example, B5 to
A3 size is set, and this is detected by the size detection sensor S2. When a stack of document sheets of a plurality of document sizes is mixedly mounted, the user specifies it by pressing a mixed mounting key mounted on the operation panel of the copying machine main body.
The paper thickness of one original paper is designated by pressing a thin paper key or a thick paper key placed on the operation panel.

As described above, the original sheet bundle thickness and the original size are automatically detected by the respective sensors, and the mixed originals and the sheet thickness are manually set.

The pressure pulse table is set in advance by these detected values and manual setting, and is stored in the nonvolatile memory, and the count C2 is determined by these sheet condition inputting means.

(2F) When the count C2 is input by the designated pulse and the drive plate 319 is further driven to continue counting the count C2, and the drive plate 319 is swung until the designated count number C2 is counted up, The winding amount of the torsion spring 317B increases, the elastic force changes almost linearly, and the pressing force increases.

When the count C2 is counted up, the movable pressing plate 317 presses the document D by the predetermined pressing force (for example, 100 g) to the feed roller 321 and the pressing motor M1 stops driving.

(2G) At the same time as the driving of the pressing motor M1 is stopped by the above count-up, the delivery clutch CL1
The drive motor M2 is turned on, the drive motor M2 is rotated at a low speed, and the document D1 is fed. That is, the upper layer original document is sent out by the feed belt 324 which starts to rotate by the driving force of the drive motor M2 rotated at a low speed, and further, the uppermost original document D1 among the plurality of original documents sent out by the reverse roller 325. Low speed V because only one sheet is separated
Delivered with 0.

(2H) The one edge of the separated and fed document D1 is detected by the bending correction sensor S5, and a predetermined time (timer T
3) After the lapse of time, the drive motor M2 is turned off, the registration clutch CL2 is turned off, and the first intermediate conveyance roller (registration roller) 331 is struck to form an accumulation, and the feeding bend of the document D1 is corrected ( See FIG. 13 (A).

(2I) After a lapse of a predetermined time (T5) after the tip of the bending correction sensor S5 is detected, the drive motor M2 is re-driven and rotated. At this time, the drive motor M2 is rotated at a high speed, the registration clutch CL2 and the transport clutch CL3 are turned on simultaneously with the delivery clutch CL1, and the document D1 is transported downstream at a high transport speed V1 (for example, 1200 mm / s). When the leading edge of the document D1 crosses the passage detection sensor S6 and is turned on, the delivery clutch CL1 that was driving the drive roller 323 is turned off, and the feed belt 324 is driven to rotate until the rear end of the document D1 passes through the sensor S6. Then, the document D is stopped by the drive rotation of the first intermediate conveyance roller pair 331 by the drive motor M2.
1 is conveyed at high speed V1. When the sensor S6 is turned on, the paper discharge motor M3 rotates at a high speed, and if a document exists in the paper discharge path, the paper is discharged at a high speed by the paper discharge rollers 351 and 352 (V1).

(2J) Further, when the timer T5 completes the timing, the pressing motor M1 is switched to the reverse rotation, the drive plate 319 and the movable pressing plate 317 are lowered, the pressing is released, and the driving plate 319 is returned to the initial position. When the home position detection sensor S3 detects the return, the pressing motor M1
To stop. Alternatively, when a plurality of originals are continuously fed, the driving plate 319 and the movable pressing plate 317 are not returned to the home position position, but based on the detection signal of the pressing detection sensor S4 or the driving start signal of the driving means in the separating direction. The descent drive of the drive plate 319 and the movable pressing plate 317 is stopped in the middle.

(2K) After the sensor S13 detects the passage of the home position detecting hole 311C on the feeding belt 311, and after a predetermined time is counted by the timer T4, the number division solenoid SL3 of the lifting means 314 is turned off, and the lifting lever is pushed. 314A
Is descended. As a result, the separating lever 315A held on the push-up lever 314A also follows its own weight downward to release the pushing-up of one end of the document stack and lightly contact the lower part of the document on the lowermost layer to separate the copies. The sensor S14 is turned on.

Here, if the original stack is the original placing section 31
When the separator lever 315A is placed below the separator lever 315A of 0 or the separator lever 315A enters between the document stacks, the copy separator sensor S14 does not detect the stop position, and the signal causes the separator lever 315A located above to be turned off by turning off the solenoid SL3. While lowering the push-up lever 314A, the solenoid S
When L4 is turned on, the separating lever 315A is slid down and retracts. Then, when the solenoid SL4 is turned off, the spring 315A is turned off.
The separator lever 315A is moved forward by being biased by E and is inserted below the cutout 311D of the feeding belt 311 below the document stack.

(2L) Next, when the leading edge of the document D1 fed at the speed V1 passes the registration sensor S7 and the signal is turned on, the driving roller 342 of the conveyor belt 341 and the second intermediate conveyor roller pair (registration) are registered. (Roller) 334 and the encoder sensor for encoder plate RE, S16, starts counting. After the predetermined count (φ1) by the encoder RE, the drive motor M2 is turned off. Further, at this time, the encoder plate RE starts counting and a predetermined count (φ2)
After that, the registration clutch CL2 and the conveyance clutch CL3 are turned off, the conveyance brake BRK1 is turned on, and the conveyance belt 34
The rotation of the first and second intermediate conveying roller pairs 334 is stopped. At this time, the leading edge of the document D1 is at a predetermined standby position (a position at a distance L1 from the stop position, for example, 236 m) of the platen glass 111.
m) and stops (see FIG. 13 (B)).

Prior to this, when the leading edge of the first original document D1 passes through the registration sensor S7 and the detection signal is turned on, the pressing motor M1 starts the pressing drive of the drive means based on the detection signal, The drive plate 319 and the movable pressing plate 317 are raised to continue pressing the subsequent document D2.

(2M) After a predetermined time (T6) from the count start (φ2) of the encoder plate RE, the drive motor M2
And the delivery clutch CL1 is turned on, and the delivery roller 321 and the feed belt 324 rotate at a low speed (V0).
Then, the document D2 is fed at a low speed and abutted against the first intermediate conveyance roller pair (registration roller) 331 to form an accumulation and stopped as in the case of the document D1 (see FIG. 13C).

(2N) Next, after a predetermined time, the drive motor M
2, the registration clutch CL2, the conveyance clutch CL3 are turned on, the conveyance brake BRK1 is turned off, and the originals D1, D
2 is conveyed at high speed (V1) and the original D1 is placed on the platen glass 11
1 When the predetermined exposure position above is reached (encoder φ
1) The drive motor M2 is turned off, and then (encoder φ
2) The conveyance clutch CL3, the registration clutch CL2 is turned off, and the conveyance brake BRK1 is turned on to suddenly stop the document D1 at the exposure position.
To a predetermined standby position (see FIG. 13D). That is, in the present embodiment, the movement amount of the document D is managed by counting the number of pulses of the rotary encoder RE with the registration sensor S7 as a reference without using the document stopper, and the document is conveyed to the reading position. It is an exact stop at the position.

(2O) With both originals D1 and D2 stopped,
The document D1 is scanned and exposed by a signal from the copying machine body (see FIG. 13E). That is, the original D1 is exposed on the first surface by the exposure lamp of the scanning exposure unit 110 while the original D1 is stopped on the platen glass 111, and the original image is formed on the photosensitive drum via the lens, the mirror, and the like. Then, a series of copying processes for the document D1 are performed.

During the above exposure operation, the drive motor M2 and the clutch C are increased by counting up the timer (T6).
When L1 is actuated, the feed belt 324 starts to rotate, the next original document D3 is sent out at a low speed (V0), the registration operation is performed by the control of the timer, and the leading edge of the original document D3 starts from the leading edge of the original document D2. It stops at the position where the distance interval L1 is maintained.

Therefore, at this time, the three originals D1 to D3 are arranged in a row in a row on the conveying path from the separating / feeding means to the reading section with a predetermined interval L1 therebetween.
At this time, the original document D1 is placed at the reading position of the platen glass 111, and the original document D2 stands by at a position that is stretched between the conveyor belt 341 and the second intermediate conveyor roller pair 334 (registration roller). D3 is waited at the position where it hits the registration roller 331, and the originals D2 and D3 are waited in a state where the subsequent conveyance can be performed stably.

(2P) Original exchange (see FIG. 13 (F)) After the exposure operation of the original D1 is completed, the conveyor belt 341 is rotated at a high speed by the high-speed rotation drive of the drive motor M2 (V1), and the paper is discharged prior to this. The motor M3 is rotated at a high speed, and the document D1 is discharged at a discharge speed V1 that is equal to the transfer speed V1 of the transfer belt 341. By the high-speed rotation of the paper discharge motor M3, the document D1 passes above the paper discharge roller 351, and the switching claw 357 has already swung by the RDH switching solenoid SL2, and the upper path is switched to open and the guide plate is passed. Proceed within 356B. When the leading edge of the document D1 is detected by the paper discharge sensor S9 during this conveyance, timers T8 and T9 start timing.
When the timer T8 counts up, the bottom return clutch CL4 is turned on and the paper discharge brake BRK2 is turned off. At this time, if the deviation detection sensor S10 is off, the deviation correction motor M4 is started to rotate in the depth direction. In addition, the sensor S10
If is on, move it to the front, turn it off, and then rotate it to the back again to stop it at the same time as it is turned on.
As for the timer, the leading end of the document D1 is the gripping piece 3 of the feeding belt 311.
The bottom return clutch CL4 is set to be turned on so as to be sandwiched by 11B.

In this embodiment, the conveyance distance from the paper discharge roller 351 to the sandwiching piece portion 311B has an interval equal to or larger than the paper passing size, but the rear end of the document D1 is discharged by a timer independent of the timer. After passing through the paper roller 351, the deviation correction motor M4 may be turned on so that the distance from the sandwiching piece 311B to the paper discharge roller 351 is maintained shorter than the original size.

(2Q) Further, the bottom return feeding belt 311
Then, the circulating paper discharge roller 355 is rotated, and the document D1 is inserted below the upper document stack. Here, the number separation means
315 separator lever 315A is a copy separator solenoid SL
4, it is raised by a certain amount upward, and the clamping piece portion 311
The document D1 whose front end is nipped by B is inserted under the final document that has not been conveyed (see FIG. 13F).

(2R) The discharge sensor S9 is at the rear end of the document D1.
After passing, the paper discharge sensor S9 is turned off, the paper discharge motor M3 is switched to the medium speed, the circulation paper discharge roller 355 is decelerated, and the document D1 is continuously sent to the document placing section 310 at the medium speed V2. The document D1 is further sent out by the circulation paper discharge roller 355 and the feeding belt 311 after the replacement operation of the document D2 is completed. At the time of this low speed switching, the bottom return clutch CL
4 is turned off to stop the drive transmission of the discharge motor M3, and at the same time, the discharge brake BRK2 is turned on to drive the drive roller 312.
The rotation of A can be switched to a low speed. As a result, the rotation of the feeding belt 311 is switched to the medium speed V2, and the document D1 is fed toward the movable pressing plate 317 at the medium speed V2 in cooperation with the circulation paper discharge roller 355 which is switched to the low speed rotation.

Since the movable pressing plate 317 is lowered immediately after the registration is completed, the original document D1 being returned to the original document placing section 310 is being operated.
Passes through the lowered movable pressing plate 317, and then collides with the document leading edge stopper 318 at a medium speed V2 and stops.

(2S) Subsequent originals are also sequentially fed, conveyed, and ejected, and when the final original D4 is sent to the registration position, the trailing edge of the original D4 leaves the break lever 315A and the break lever 315A. Moves upward, the copy number separating sensor S14 is turned on, and it is detected that the final original document of the first circulation is sent out.

(2T) After the final original document D4 is conveyed to the second stop position, the original document D1 returned to the original document placing section 310 is again fed out during the exposure of the original document D3. Similarly, when D2, D3 and D4 are sent out and D4 returns, the copy number separating solenoid SL3 is operated to move the separating lever 31 to the lower side of the document D4.
Insert 5A. This operation is repeated a predetermined number of times.

In this embodiment, after the registration feeding is completed, the movable pressing plate 317 is configured to return when the movable pressing plate 317 is lowered, but the feeding operation may be performed after the completion of the returning. here,
A paper pressing lever 319 provided on the upstream side of the separating lever 315A in the conveying direction serves to surely insert the returning original document under the original document stack, and lightly presses the original document by its own weight.
The paper pressing lever 310Z is also effective for stabilizing the operation of the separating lever 315A when conveying curled paper or a small number of originals.

(3) R-RDH Mode (Double-sided Original Circulation and Transport Mode) The above operation is for single-sided copying of a single-sided original in the RDH mode. In the R-RDH mode in which a double-sided original is copied on both sides, the original is reversed in the first cycle, only odd pages are copied (see FIG. 9C), and even pages are copied in the second cycle (FIG. 9 ( See D)). Of course, the copying machine body
100 side copy paper feeding operation is also in the above RDH mode, RR
The movement according to the DH mode will be performed.

FIG. 14 is a timing chart of the drive system in the R-RDH mode, and FIGS. 15 and 16 are schematic diagrams showing the document conveying process in the R-RDH mode for copying both sides of a two-sided document. Document transportation for even-page copying of small-sized documents will be described below with reference to FIGS. 10, 12, 14, 15, and 16.

(3a) FIG. 15 (a) shows a state in which the leading original D1 on the even-numbered page in the second cycle is intermediately conveyed. When the preceding final document D4 of the first cycle is stopped at a predetermined position on the platen glass 111, the first document D1 of the second cycle is fed to the platen glass 111.
At a high speed (V1), the leading edge of the original document D1 is stopped at a standby position maintaining a predetermined distance L1 from the leading edge of the preceding original document D4.

(3b) Next, the original D4 is a platen glass
Exposure processing is performed at a predetermined position on 111. During this D4 exposure operation, the next original D2 is sent at a low speed (V0) and the registration roller 331 waits for registration (see FIG. 15B).

(3c) The originals D4 and D1 are simultaneously conveyed at the same high speed (V1) by the forward rotation of the conveyor belt 341, and a predetermined time elapses after the trailing edge of the original D1 passes the registration sensor S7. M3 and the conveyor belt 341 are driven in reverse to feed the document D1 to the reverse path 336. On the other hand, the final original D4 in the first cycle is strongly nipped by the paper discharge roller 351,
The conveyor belt 34 is rotated in the reverse direction by the driving force of the discharge motor M3.
It is conveyed at high speed V1 in the direction of the paper discharge passages f, g, n against 1. The document D4 is switched to the medium speed V2 before the completion of discharge, and at this time, the document D4 is decelerated by the brake means BRK2 and then conveyed at the medium speed V2 for a predetermined time (see FIG. 15 (c)).

(3d) Subsequently, the document D1 is fed back, is reversed through the path i, and is re-entered on the platen glass 111 with the second surface facing downward. The document D4 advances toward the document placing section 310. The reversal detection sensor S17 turns off M2 after a lapse of a predetermined time to detect the leading edge of the document D1 and switches to the normal rotation, but the reversing roller always rotates in the normal direction, so that the document D1 is continuously fed onto the platen glass 111. At this time, the sensor S7
After a lapse of a predetermined time from the detection of the leading edge passage of the document D1 by the, the delivery clutch CL1 is turned on, and the document D2 is delivered at the same transport speed (V1) with a predetermined distance from D1 (FIG.
(See (d) and (e)).

(3e) The originals D1 and D2 are simultaneously conveyed (V1), the original D1 is suddenly stopped at a predetermined position at the right end on the platen glass 111, and the second surface is exposed. During this exposure process, the document D2 advances to a predetermined standby position on the platen glass 111 and is stopped. D3 is sent at a low speed V0 during D1 exposure and stops at a position where it hits the registration roller 331 (see FIGS. 15 (f) and 16 (g)).

(3f) After the second surface of the document D1 is exposed, the document D1 is conveyed to the discharge reversing section 350 at a high speed V1 by the discharge roller 351 which rotates in the normal direction and the reverse discharge roller 354, and the reverse discharge path 3
After the document trailing edge has passed the sensor S11 and has passed a predetermined time, the drive of the paper discharge motor M3 is stopped. At the same time, the document D2 enters the platen glass 111 surface at high speed V1 (see FIG. 16 (h)).

(3g) The original D2 is turned upside down by the turning guide plate 336, and the platen glass is turned with the fourth side facing downward.
Enter high speed V1 at one end of 111. In the meantime, the leading document D1 passes through the reversing paths j, k, m, and n in the discharge reversing unit 350, and the speed V1 is applied to the document placing unit 310 with the first surface facing upward.
At high speed, sensor S9 detects the trailing edge of the document, then medium speed V
2 and proceed (see FIG. 16 (i)). As a result, the document D1 is nipped by the paper discharge roller 355 and the medium speed V2
And the leading edge of the document D2 is on standby for a predetermined time after the registration sensor S7 is turned on.
Is sent out (V0). Further, similarly to the case of the RADF mode, the speed switching from the high speed V1 to the low speed V2 may be performed when the front and rear edges of the document D are replaced.

(3h) After the registration sensor S7 detects the leading edge of the document D2, the document D3 is continuously sent out, and the document D
2 and D3 are simultaneously conveyed, and the original D2 is a platen glass 11
1 Stop at a predetermined position on the right end and receive exposure processing. At this time, the document D3 advances to a predetermined standby position on the left side of the platen glass 111 and stands by, and the leading end spacing of these documents D2 and D3 is maintained at L1. The document D4 is sent out during the exposure of the document D2 and stopped at the position where it hits the registration roller 331. Document D1 continues to be V2 at medium speed and the document end stopper
Proceed toward 318 (see FIG. 16 (j)).

In the same manner, the even-numbered page original is turned upside down by the intermediate feeding unit 330, and is fed onto the platen glass 111 with the even-numbered page face down, and is switched back by the paper ejection reversing unit 350 after the exposure processing. It is inverted and returned to the lowermost layer of the original stack on the original placing portion 310 with the odd page surface facing upward (see FIGS. 16 (k) and 16 (l)).

The above is the operation of conveying a small-sized document.
When conveying a large-sized document (B4 size, A3 size, 11-inch width paper), etc., the standby position for the subsequent document is provided on the upstream side of the platen glass 111 at the branch portion between the document forward conveyance path c and the reverse conveyance path i. It may be set near the registration roller 334.

The document feeding operation in the RDH mode and the R-RDH mode has been described above.
Even in the case of discharging from the image reading unit to the discharge tray unit 360 outside the apparatus in the F mode, by setting and switching the document discharge speed to the above-described V1> V2, the documents are placed on the trays 361 and 363. It can be placed without scattering. In this example, V1 = 1200 mm / s, V2 = 600 mm / s
Is set to.

In the above-mentioned automatic document feeder, the image reading stop reference position of the document is set on the right end side of the platen glass 111 in the drawing (on the side of the document discharge section), but the present invention is not limited to this. Instead, the invention can be applied to the one in which the image reading stop reference position of the document is set on the left end side (the document feeding unit side) of the platen glass 111.

[0122]

As described above, according to the automatic document feeder of the present invention, the documents set or re-stacked on the document placing table are fed from the uppermost sheet of the document placing table to the sheet feeding section and the processing section. After that, since it is returned to the lowermost layer of the original stack on the original placing table again in a closed loop, the originals are not contaminated due to front and back friction between the originals. Further, the automatic document feeder of the present invention does not require a suction means or the like and has a simple structure, so that it is not only effective in reducing the manufacturing cost, but also excellent in that noise and vibration are not generated. Have advantages.

Further, according to the present invention, with a simple structure and control, a plurality of originals which are continuously circulated and conveyed can be conveyed sufficiently close to the preceding original and the succeeding original. That is, pre-feeding can be completed up to a predetermined standby position for subsequent originals that are conveyed forward or reversely before the exposure of the preceding originals is completed. Therefore, it is possible to remarkably shorten the exchange conveyance time of the succeeding document on the document reading surface, and as a result, it is extremely effective in shortening the copying time (improving copy productivity). In particular, by switching the document discharge speed between high and middle two stages, it is possible to discharge the documents at high speed without interfering with each other even if the intervals between the documents are close, and to accurately stop and align with the stopper by switching the medium speed discharge. Therefore, it is suitable for document circulation conveyance. Further, even in the RADF mode in which the sheet is discharged to the discharge tray, the alignment property on the discharge tray can be improved.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a copying machine equipped with an automatic document feeder according to the present invention.

FIG. 2 is a sectional view of the automatic document feeder.

FIG. 3 is a perspective view of a main portion of a document placing portion.

FIG. 4 is a perspective view of a sheet feeding belt and related members of the document placing portion.

FIG. 5 is a front sectional view of a document placing section and a feeding section.

FIG. 6 is a side view of the separating means and the pushing-up means.

FIG. 7 is a schematic diagram showing a return document being conveyed in a document circulation mode on a document placing section.

FIG. 8 is a schematic diagram showing a document conveyance path in ADF mode and R-ADF mode.

FIG. 9 is a schematic diagram showing a document conveyance path in an RDH mode and an R-RDH mode.

FIG. 10 is a configuration diagram showing a drive system of an automatic document feeder.

FIG. 11 is a block diagram of the drive system.

FIG. 12 is a timing chart of the drive system.

FIG. 13 is a timing chart of the drive system.

FIG. 14 is a schematic diagram showing an odd-numbered page original transport path in the R-RDH mode.

FIG. 15 is a schematic diagram showing the first half of the even-numbered page document conveyance process in the above mode.

FIG. 16 is a schematic diagram showing the latter half of the even-numbered-page original conveying process in the above mode.

[Explanation of symbols]

 100 Copying machine main body 110 Scanning exposure section 111 Platen glass (reading section) 120 Image forming section 300 Circular automatic document feeder (RDH device) 310 Document placing section 311 Feeding belt (carrying-in means) 314 Separation lever lifting means ( 315 Separating means 317 Movable pressing plate 318 Original document end stopper 320 Feeding section 321 Feeding roller 324 Feed belt 330 Intermediate conveying section 331 Registration roller (first intermediate conveying roller pair) 334 Registration roller (second intermediate conveying roller pair) ) 340 Conveying section 341 Conveying belt 350 Ejection reversing section (ejection section) 351 and 352 Ejection roller 354 Reversed ejection roller 355 Circulation ejection roller (deviation correction roller) 360 Ejection tray section 364 Reversed ejection path a, b, c, d, e, i Paper feed path f, g, h, j, k, m, n Paper discharge path S9 Paper discharge sensor (document trailing edge detection means) S11 Reverse paper discharge sensor V0 Document preliminary feeding speed (Low Speed) V1 document introduction speed (high speed) V2 document conveyance speed (medium speed) D, D1 to D4 document (document stack) BRK2 paper ejection brake (brake means) T1 to T6 timer

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location H04N 1/00 108 B 7046-5C

Claims (3)

[Claims] 1. A feeding unit that separates and feeds one of a plurality of documents stacked on a document placing unit and feeds it to an image reading unit; and a feeding unit that feeds the image reading unit. The document that has been conveyed and stopped at a predetermined image reading position, and then carries out the document after image reading, and the document that is located downstream from the image reading unit in the carrying direction and is carried out from the carrying unit. In an automatic document feeder including a stacking unit or a discharge unit that discharges to a discharge tray outside the machine, the rear end in the traveling direction of the document discharged from the image reading unit to the discharge unit is the front end in the document discharge direction. When the original reversal discharge mode in which the original is conveyed to the original and the original is reversed and then discharged to the original tray or the discharge tray, with respect to the conveying speed V1 until the original is completely discharged from the image reading unit, Paper discharge provided near the final discharge position of the discharge unit An automatic document feeder, characterized in that the feeding speed V2 until the original of the roller comes off is set to a low speed. 2. The automatic document feeder according to claim 1, wherein the switching of the transport speed is performed when the document is reversed at the discharge portion so that the rear end of the document becomes the front and the front and rear ends are replaced. 3. A reverse sheet discharge sensor for detecting a document edge at the time of document reversal is provided at a discharge section downstream of the image reading section in the document discharge direction, and a document edge passage is detected near the discharge final position of the discharge section. The automatic document feeder according to claim 1 or 2, further comprising a paper discharge sensor.