JPH06222638A - Circulation type automatic document carrier - Google Patents

Abstract

PURPOSE:To provide an automatic document carrier capable of surely stabilizing the circulating/carrying actions of a document in the recirculation type automatic document of a top feeding and bottom returning system and increasing a copy processing speed by the speeding up of the conveyance of the document. CONSTITUTION:The recirculation type automatic document carrier of a document top feeding and bottom returning system is composed of a document placing part 310 composed of a feeding belt 311 on which a group of documents can be placed on a part and which moves the document up to a feeding start top end position, a paper feeding part 320 separating/feeding one of plural sheets of documents placed on the document placing part 310 to an image reading part, a carrying part carrying the fed document into the image reading part and further, carrying away the document after an image is read and an ejecting part ejecting the document carried away from the image reading part to the document placing part 310. A part of the document contact surface of the feeding belt 311 is formed as a belt-like projection line 311E whose longitude is in the carrying direction, with respect to the other surface. The surface of the projection line 311E is formed to one having a high coefficient of friction and a document pressing member 3100 capable of coming in press-contact with the projection line 311E is provided.

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 apparatus such as an electrophotographic copying machine or an automatic document feeder in an image reading apparatus, and more particularly to a single-sided or double-sided recording original loaded on an original placing portion. Separate the sheets and feed them to the image reading unit,
The present invention relates to a circulating automatic document feeder having a document feeding mode (RDH mode) and a double-sided document reversing feeding mode (R-RDH mode), which is capable of returning the read document to the document placing section again and feeding it repeatedly. .

[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 (RADF) equipped with 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) that can be returned and repeatedly processed has also been proposed.

This circulating automatic document feeder (RDH)
Makes copies one by one in one cycle, and circulates the original for the number of copies.

Further, recently, the present applicant has also provided a circulating automatic document feeder (R-RDH) in which a document front and back surface reversing mechanism is added to the above RDH (Japanese Patent Application No. 63-20228).

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 recording and final processing. 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.

[0009] Such a bottom-feeding top-returning RDH
In the apparatus, when the document is fed out, problems such as the disorder of the document image due to dirt and rubbing on the document front and back surfaces caused by 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.

The sheet storing and feeding apparatus disclosed in Japanese Patent Laid-Open No. 3-205273 discloses a sheet feeding and feeding apparatus for an RDH apparatus. The vertical pressing member is arranged at the position. Further, JP-A-4-164786 and JP-A-4-164787 disclose circulation type RDH devices for rotating an endless conveyor belt.

[0012]

In these RDH apparatuses, since the originals after the image reading processing are circulated, placed on the original placing portion and re-fed, the originals ejected from the ejection means are aligned. Need to be placed accurately. Also ADF, R-
Even in the ADF mode, the paper is discharged unevenly on the paper output tray,
Problems such as scattered originals or popping out of the tray and falling may occur.

In order to solve these problems, the present applicant has filed Japanese Patent Application Laid-Open No. 4-217568 and Japanese Patent Application No. 4-209199.

However, Japanese Patent Application No. 2-403220 and Japanese Patent Application
In No. 4-209199, there is no upper guide for the original that returns to the original placement section, so if the compression curl is large, it may not return in an orderly manner. Further, since the original weight of the compressed paper is used to carry in the paper, a sufficient conveyance force may not be given when the number of originals is small.

[0015]

SUMMARY OF THE INVENTION The present invention solves various problems in the conventional automatic document feeder as described above, is stable even during a high speed feeding operation, and can cope with various document sizes. An object of the present invention is to provide a feed / bottom insertion type circulating automatic document feeder.

In particular, the present invention, in a circulating automatic document feeder for performing a top feed bottom return operation, makes it possible to reliably return the document returning to the document placing portion to the document feeding start front end position. It is to provide a document feeder.

The circulation type automatic document feeder of the present invention which achieves the above-mentioned object, is capable of stacking at least one set of a plurality of documents and is also composed of a document feeding belt for moving the document to the feeding start front end position. The placing section, a sheet feeding section that separates and feeds one of the plurality of originals stacked on the original placing section and feeds it to the image reading section, and the fed original. An original feed bottom-returning system of a document feed type including a conveyance unit that carries the document into the image reading unit and further carries out the document after the image reading, and a discharge unit that discharges the document carried out from the image reading unit to the document placing unit. A circulating automatic document feeder, wherein a part of the document contacting surface of the feeding belt is formed into a strip-shaped projection strip that is long in the transport direction with respect to the other surface, and the surface of the projection strip has a high friction coefficient. Original pressing that is formed on the surface and can be pressed against the protrusion It is characterized in providing the member.

In the circulating automatic document feeder of the present invention, the document pressing member feeds the document pressing member until the pressure contact position with the feeding belt reaches the document feeding leading end position. It is characterized by being installed like.

[0019]

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 copy paper post-processing device (finisher (sorter with stapler device, etc.) FNS device).

The copying machine main body 100 includes a scanning exposure unit 110, an image forming unit 120, a paper feeding unit 130, a conveying unit 140, a fixing unit 150, a paper discharge switching unit 160, a plurality of paper feeding cassettes 170, and copy paper 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 documents 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 is swingable around a swing shaft 317A on the leading end side of the document feeding portion 310 on the downstream side of the document feeding. 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. A document pressing member 310 is provided above the document placing portion 310.
0 is a support portion that engages with a support bearing portion provided at one end of the feeding portion 320
It is swingably supported around 3101. The document member 3100 presses the document stack stacked on the feeding belt 311 from above to ensure feeding, and is circulated and discharged from the discharge reversing unit 350 to be on the feeding belt 311. It also plays a role of guiding the upper surface of the originals returning above the original stack and feeding them to the pressing position.

The actuator portion provided on the drive plate 319 includes 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. 4 is a perspective view of the feeding belt 311, FIG. 5A is a sectional view of the feeding belt 311, and FIG. 5B is a partially enlarged sectional view thereof. A wide feeding belt 311 on which a document D is loaded, supported and rotatable is provided with a driving roller 312A and a driven roller 31.
It is an endless belt wound around 2B with 2B. 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 portion 311B of the feeding belt 311 and the inner peripheral surface of the feeding belt 311 are rough surfaces, and it is effective to grip the leading edge of the document by frictional force and prevent slipping with the driving roller 312A. . Further, on the outer surface of the feeding belt 311, a plurality of strip-shaped protrusions 311E are provided between the lines A and B in FIG.
Are formed slightly higher than the outer surface of the feeding belt 311. It is desirable that the protrusion 311E is a rough surface having a high friction coefficient, and the other outer surface of the belt is a smooth surface having a low friction coefficient. In addition, in this embodiment, as shown in FIG.
Although the strip-shaped protrusions of the book are provided in parallel with the original transport direction,
It is also possible to use three or more protrusions. Also, the above-mentioned protrusions 31
1E is a feeding belt formed of a plurality of thin plates such as chloroprene rubber having a predetermined length and width and an outer surface having a high friction coefficient.
You may adhere | attach or weld between 311 A-B (refer FIG. 5), and may arrange them in parallel. Alternatively, the protrusion line portion 311E having the protrusion position and shape and a high friction coefficient may be integrally formed with the feeding belt 311.

The original pressing member 3100 is supported by a supporting portion 3101 which engages with a support bearing portion provided on a supporting frame of the feeding portion 320 and is swingable, and is biased by its own weight or spring to press the original pressing portion. 3102 partially presses the document D above the protrusion 311E of the feeding belt 311. At the document pressure contact position by the document pressing member 3110, the protrusions 311E of the feeding belt 311 and the document pressure contact part 3102 hold the document until the leading edge of the document D having the minimum size reaches the document leading edge stopper 318. It is set in such a position. Further, the document pressing member 31
00 is the original pressure contact part 3102.
Forming 3103. The guide portion 3103 is provided on the document placing portion 31.
The document D is a guide for initially manually placing the document stack D on the document stack 0, and is circulated and conveyed to be discharged from the discharge reversing unit 350 and returned above the document stack on the feeding belt 311.
Guides the upper surface of the sheet and feeds it into the original pressure contact portion 3102. 311C 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 reflective sensor S13 for detecting the home position of the feeding belt, and the feeding belt 311C is detected. The stop position of the sandwiching piece 311B of 311 is controlled.

In FIG. 3, a sheet discharge brake BRK2 and a bottom return clutch CL4 connected to a sheet discharge motor M3 as a drive source are provided at the shaft end of the rotary shaft 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 fixing plate 313 supports the document stack D on the feeding belt 311 by placing it on a flat surface.

Reference numeral 315 is a copy number separating means for separating 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 and is bottomed in the lowermost layer of the stacked original bundle. Is. The separation lever 315A of the copy separation means 315 is spring-biased, and the solenoid SL
3, SL4 is used for ascending / descending and forward / backward and diagonal ascending / descending driving in the direction orthogonal to the sheet feeding.

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

For the original stack placed on the original placing section 310, the original pressing member 3100 is lifted upward to be placed or inserted along the guide section 3103, and the feeding belt 311 and A width stopper plate that stacks on a movable pressing plate 317, which will be described later, and regulates the document bundle in the document width direction by one side base.
The document is abutted against 316, and at the same time, the leading edge of the document is abutted against a document leading edge stopper 318, which will be described later, and aligned and placed. At this time,
The original placing surface above the feeding belt 311 is a smooth surface (see B- in FIG. 5).
C surface). Further, at the time of placing the document, the separating lever 315A is pressed by the own weight of the document stack and descends,
The bottom layer of the document stack is being pushed up lightly. Further, the swingable paper pressing lever 310Z provided on the upstream side of the separating lever 315A for conveyance assists the returning original document to be surely inserted under the original document stack, and the original surface is lightened by its own weight. Pressure contact. 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. 6 is a front sectional view of the document placing portion 310 and the feeding portion 320, and FIG. 7 is a separating means 315 and a separating lever lifting means 3
14 is a side sectional view of a document pressing portion of 14 and a feeding belt 311. FIG.

In these figures, the feeding belt 311
A separating means 315 and a pushing-up means 314 are fixedly provided on one fixed side plate 310A that axially stops the driving roller 312A and the driven roller 312B that rotate. That is, in the vicinity of one side end of the feeding belt 311, the pushing means 314 is provided on the upstream side of feeding,
A copy number separating means 315 is fixedly provided on the downstream side of the arrow.

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 can swing about a fulcrum shaft 314D planted on the upper portion of the substrate 314B, and is biased in one direction by a torsion spring 315E. The base of a long rod-shaped push-up lever 314A is driven into the other end of the rocking lever 314C so that the tip thereof projects. The push-up lever 314A is the separation lever 3
It contacts the lower surface of the tip of 15A and holds it so that it can 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 inclined by the weight of the weight 315G, and the right end portion is raised. It has become (position of Figure 7). Then, the pin 315H reaches the top dead center of the cam groove portion 315J in the figure 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 in FIG. 7). 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. When the first page of the returning original reaches the uppermost position (the position shown in FIG. 7) as the number of returning originals increases,
It becomes free and jumps up into the upper space (position in Figure 7). At this time, the copy number sensor S14 is turned off.

The separating lever 315A is a solenoid S3.
Is pulled to the left side in the drawing by the suction operation (position in FIG. 7). 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.
The separating lever 315A connected by F is moved to the left. The pin 315H planted in the separating lever 315A moves obliquely downward in the cam groove 315J and comes into contact with the left end of the cam groove 315J to stop the movement. At this time, leaf spring 315K
Is in sliding contact with the upper surface of the separating lever 315A, and the separating lever 3
Prevent 15A from jumping up.

When the energization of the solenoid SL3 is turned off after a predetermined time, the swing lever 315c is supported by the spring 315E at the fulcrum 31.
Rotate clockwise around 5D to move the lever 315A to the right (position in FIG. 7). At this time, plate 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. In order to prevent this, before the cutout portion 311D passes the upstream side of the document stack, 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 tip of the lever 315A is Be sure to insert it above the original to be returned. 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. The separation lever 315A is raised by a predetermined amount so that the preceding notch portion 311D does not collide with the document stack,
Retract the relevant part of the document stack upward. Therefore, the solenoid SL4 is actuated by the signal of document replacement to attract the plunger SL4A, swing the swing lever 314C around the fulcrum shaft 314D, and raise the push-up lever 314A. 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, and the cutout portion 3 of the feeding belt 311 is lifted.
At the same time as allowing the 11D to pass, the return original is reliably guided below the separating lever 315A.

As shown in FIGS. 2 and 6, a movable pressing plate 317 of movable pressing means is provided on both side plates which are integrated with the fixed bottom plate 310A, on the downstream side of the document feeding of the feeding belt 311. A drive plate 319 is screwed to a swing shaft 317A supported by a bearing, and can swing integrally. An elastically deformable member (for example, a torsion spring) 317 is attached to the swing shaft 317A.
B is wound, and both ends thereof are in pressure contact with the drive plate 319 and the movable pressing plate 317, respectively, and are biased by the spring. At this time, the movable pressing plate 317 and the drive plate 319 are separated from each other by the torsion spring 31.
Although it is pushed in the opening direction of 7B, the lower end of the movable pressing plate 317 comes into contact with one end of the drive plate 319, and the opening angle between the two is restricted so as not to open beyond a certain amount. 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. Further, the gear G1 is attached to one shaft end of the swing shaft 317A.
Is fixed, and the gear G is fixed to the drive shaft of the pressing motor M1.
2 (see FIG. 3).

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. 8 is a schematic diagram showing a process of transporting the document D discharged from the discharge reversing unit 350 to the feeding belt 311 of the document placing unit 310 and the movable pressing plate 317.

After the passage of the leading edge of the original document D1 is detected by the paper discharge sensor S9, a predetermined time elapses (the leading edge of the original document is clamped by the clamping piece 311B
When the leading end portion of the document D1 is pinched by the holding piece portion 311B of the feeding belt 311 which is rotated from the home position, the feeding belt is further rotated.
The sheet is sandwiched on the rough surface of 311 and is inserted into the lowermost layer of the stack of unprocessed originals D and conveyed to the left in the figure (FIG. 8).
(See (A) and (B)). As described above, at this time, the separating lever 315A is pushed up by the push-up lever 3 via the solenoid SL4.
At 14A, 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 or constant than the surface linear velocity of the circulation paper discharge roller (deviation correction roller) 355 of the paper discharge reversing unit 350. Further, the protruding strip portion 3 of the feeding belt 311 which comes into contact with the document D1
11E (between A and B in FIG. 5) is a protruding (about 0.5 to 1 mm) rough surface, and the document pressing member 3100 receives an appropriate pressing force. It is pressed against the surface of the feeding belt 311 by its own weight and its pressing force, and is reliably held by the feeding belt 311 and fed (see FIG. 8C).

Although the leading edge of the return document D1 fed by the feeding belt 311 is separated from the surface of the feeding belt 311, it is still fed by the rough surface of the feeding belt 311 and the movable pressing plate 317.
Glide on the top. That is, the document D held on the feeding belt 311 is moved downward along the driven roller 312B of the feeding belt 311, and the movable pressing plate 317 located slightly below the upper surface of the feeding belt 311. Gliding on the upper surface of.

When the leading edge of the document D1 hits the document leading edge stopper 318, the document D1 varies depending on the document size.
The second half of the table stops while being placed on each of the rough surface and the smooth surface of the rotating feeding belt 311 (see FIG. 8D).

The feeding belt 311 further rotates and stops at the home position. At this time, the original contact surface of the feeding belt 311 is a smooth surface (see FIG. 8E). Therefore, if the entire 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 that are normally and reversely driven to form a conveying path for conveying the document D sent from the feeding unit 320 to one end of the platen glass 111. There is.

Further, a reversing means is provided on the left side of the third 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 the paper output rollers 351, 352,
Switching claws 353, 357, reverse paper ejection roller 354, circulation paper ejection roller 3
55 and guide plates 356A, 356B, 356C and the like. The paper discharge rollers 351, 352, the reverse paper discharge roller 354, and the circulation paper discharge roller 355 are driven by the paper discharge motor M3. The paper discharge rollers 351, 352, the reverse paper discharge roller 354, and the circulation paper discharge roller 355 are driven by a paper discharge motor M3,
The paper discharge rollers 351 and 354 are driven to rotate in the forward and reverse directions, and the paper discharge roller 35
5,352 are always driven in forward rotation. 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 unit 360 is fixedly provided near the discharge opening of the discharge reversing unit 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 (resin tray that is swingable by being 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 conveyed from the reverse discharge roller 354 is moved up the reverse discharge path 364 and the rear end is detected by the sensor S11. After a predetermined time, the original D is temporarily stopped and then the reverse discharge roller 354 reverses. It is introduced into the automatic document feeder 300 by the rotation drive, and in the R-ADF mode of the double-sided document, it is discharged to the outside of the machine by the discharge roller 352 of the discharge reversing unit 350 through the guide 356C and the upper surface of the movable tray 363. Placed on.

When the movable tray 363 of the paper discharge tray section 360 is rotated and unfolded, the upper surface side of the fixed tray 361 is
By extending to the upper surface side of the movable tray 363, it is possible to eject and place a large original such as A2 size paper or fanfold paper (CFF).

In addition, the reverse circulation mode (RR
At the time of DH), the switching claw 357 is switched downward, and the document D once conveyed to the reversal discharge path 364 is R-ADF.
It is reversed in the same manner as in the mode, and is returned from the reverse sheet discharge roller 354 through the guide plates 356C and 356B and the circulation sheet discharge roller 355 to the document placing section 310 with the same surface as the platen glass 111 facing up.

FIG. 9 is a schematic diagram showing the document transport path (dotted line) in the RDH mode and the R-RDH mode.

FIG. 9 (A) is a schematic view of the RDH mode showing the original circulation conveyance for a single-sided original and a single-sided copy. The one-sided document D is sent from the platen glass 111 to i through the progressive circulation paths a, b, c, d, and e, and further, the platen glass 111.
To the path f, g, n of the discharge reversing unit 350 after the exposure process.
After that, the nipping piece portion 31 of the feeding belt 311 of the document placing portion 310
1B enters and is conveyed by the feeding belt 311 and returned to the bottom of the original stack.

FIG. 9B is a schematic diagram of the R-RDH mode showing the circulation and conveyance of a document at the time of copying a double-sided document or a two-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 again through the feeding paths a, b, c, d, and the surface is inverted by i. Then, the original document D after the exposure process reaches the exposure j, k, and the surface when it is sent back by switching back is set up. And is returned to the document placing section 310 via the paths m and n.

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 to rotate 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) Document Bundle Placement 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 R-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-Returning Feeding Belt Home Position Search Operation The bottom-returning 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, and after a predetermined time, the bottom return clutch CL4 is turned off, and at the same time the paper discharge brake BRK2 is turned on. Then, the drive roller 312A is suddenly stopped. As shown in the figure, the bottom return feeding belt 311 is arranged such that the holding piece portion 311B is an 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. FIG. 13 is a schematic diagram showing a process of conveying a document on one side.

(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 ADF and copy 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 driving roller 312A is rotated and the feeding belt 311 is rotated. When the detection hole 311C of the feeding belt 311 passes through the belt home position sensor S13, the detection signal causes the feeding belt to wait for a predetermined time.
Stop 311. After that, the number separator solenoid SL
3 turns on and passes through the notch 311D to separate lever 3
15A contacts the bottom layer of the original stack.

(2C) When the copy button is turned on, the pressing motor (stepping motor) M1 is driven and rotated, and the swing shaft is moved.
The movable pressing plate 317 oscillates and rotates via the drive plate 319 fixed to 317A and the torsion spring 317B, and the leading end of the movable pressing plate 317 rises to lift the stacked document stack 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 brought into light contact with the outer peripheral surface of the feed 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 holding the feed roller 321 comes into contact with a fixing member (not shown) and stops. However, the drive plate 319 is further driven and rotated to rotate counterclockwise while compressing the torsion spring 317B, and the distance between the movable pressing plate 317 and the drive plate 319 is narrowed. 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 document bundle D is detected by the output of the count C1, and the press is predetermined by the document 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 the manual setting and is stored in the non-volatile memory, and the count C2 is determined by these sheet condition inputting means.

(2F) When the count C2 is input by the above 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 counts 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 with the predetermined pressing force (for example, 100 g) to the feeding 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 feeding is started. That is, the feed belt started to rotate by the driving force of the drive motor M2 rotated at a low speed.
The original document in the upper layer is sent out by 324, and only the uppermost original document D1 among the plurality of original documents sent out by the reverse roller 325 is separated and fed at a low speed.

(2H) The front end of one sheet of the document D1 separated and fed is detected by the curl correction sensor S5, and a predetermined time (timer T
3) After a 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) Before the timer T1 finishes timing, the timer T2 turns off the paper discharge motor M3 and the paper discharge brake BRK2, the drive roller 312A suddenly stops rotating, and the gripping piece 311B of the feeding belt 311 is stopped. Set the home position of.

(2J) After a lapse of a predetermined time (T5) after the tip is detected by the bending correction sensor S5, 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 at the same time as the delivery clutch CL1, and the document D1 is turned on.
Is transported downstream at high speed. When the leading edge of the document D1 crosses the passage detection sensor S6, the delivery clutch CL1 that was driving the drive roller 323 is turned off, and the feed belt 32 is released.
4, the document D1 is driven to rotate until the trailing edge of the document D1 passes through the sensor S6 and then stops, but the drive rotation of the first intermediate conveyance roller pair 331 by the drive motor M2 causes
The document D1 is conveyed at high speed V1. Further, when the sensor S6 is turned on, the paper discharge motor M3 rotates at a high speed, and if a document is present in the paper discharge path, the paper is discharged at a high speed by the paper discharge rollers 351 and 352.

(2K) Further, when the timer T5 completes the timing, the pressing motor M1 is switched to the reverse rotation, the driving plate 319 and the movable pressing plate 317 are lowered, the pressing is released, and the driving plate 319 is moved to the initial position. When the home position detection sensor S3 detects that the pressure motor M1 has been returned to, the pressing motor M1 is stopped. 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.

(2L) 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 T3, the member separating solenoid SL3 of the lifting means 314 is turned off, and the lifting lever is pushed. 314A
Is descended. As a result, the separator lever 315A held on the push-up lever 314A also follows its own weight downward to release the push-up of one end of the document stack, and retracts to the bottom of the lowermost document, and the copy number sensor S14 is turned on.

Here, if the original stack is first placed on 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 inclines and slides back, and subsequently, 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.

(2M) Next, when the leading edge of the document D1 passes the registration sensor S7 and the signal is turned on, the conveyor belt 34
Counting is started by the encoder sensor S16 for the encoder plate RE directly connected to the first driving roller 342 and the third intermediate conveying roller pair (registration roller) 334. 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 after a predetermined count (φ2), the registration clutch C
L2 and the transport clutch CL3 are turned off, and the transport brake BR
K1 is turned on, and the rotation of the conveyor belt 341 and the third intermediate conveyor roller pair 334 is stopped. At this time, the leading edge of the document D1 reaches a predetermined standby position (a position at a distance L1 from the stop position, for example, 236 mm) of the platen glass 111 and stops (see FIG. 13B).

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

(2N) After a predetermined time from the count-up (φ2) of the encoder plate RE, the drive motor M2 and the delivery clutch CL1 are turned on, and the delivery roller 321
Then, the feed belt 324 rotates at a low speed to feed the original D2 at a low speed, hit the first intermediate conveyance roller pair (registration roller) 331 to form an accumulation and stop the same as the above-mentioned original D1 ( See FIG. 13 (C).

(2O) After a predetermined time, the drive motor M2, the delivery clutch CL1, the registration clutch CL2, and the conveyance clutch CL4 are turned on, the conveyance brake BRK1 is turned off, the originals D1 and D2 are conveyed at high speed, and the original D1 is platen glass. When the predetermined exposure position on 111 is reached, the drive motor M2 is turned off, and further, the transport clutch CL3 is turned off and the transport brake BRK1 is turned on to stop the document D1 at the exposure position, and at the same time, the document D2 is placed on the platen glass 111. Stop at the specified standby position (Fig. 1
3 (D)). That is, in the present embodiment, the movement amount of the document D is determined by the registration sensor S7 without using the document stopper.
It is managed by counting the number of pulses of the rotary encoder RE with reference to, and is conveyed to the reading position.

(2P) When both originals D1 and D2 are 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 exposure operation, the drive motor M2 and the clutch CL1 are actuated by the count-up of the timer, the rotation of the feed belt 324 is started, the next original D3 is sent out at a low speed, and the resist is controlled by the timer. The operation is performed, and the document D3 is stopped at a position where the front end of the document D3 maintains a predetermined distance L1 from the trailing end of the document D2.

Therefore, at this time, the three originals D1 to D3 are arranged in a row at a predetermined interval L from each other on the conveying path from the separating / feeding means to the reading section. 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 transport belt 341 and the second intermediate transport 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.

(2Q) Original exchange (see FIG. 13 (F)) After the exposure operation of the original D1 is completed, the conveyance belt 141 is rotated by the high speed rotation drive of the drive motor M2, and prior to this, the paper discharge motor M3 is driven at high speed. The document D1 that has been exposed is rotated and passes through the paper discharge reversing unit 350 to return to the bottom on the document placing unit 310.

(2R) Due to the high speed rotation of the paper discharge motor M3, the document D1 has already passed through the reverse paper discharge passage 364 of the paper discharge tray 360 through the reverse paper discharge roller 354 and the guide plate 356C and has already passed through the RDH.
The switching claw 357 swings by the switching solenoid SL2, and the guide plate 356 is passed through the branch portion where the upper passage is switched and opened.
Proceed in B. When the leading edge of the document D1 is detected by the paper discharge sensor S9 during this conveyance, the timer starts counting. When the timer counts up, the bottom return clutch CL4 is turned on. At this time, if the deviation detection sensor S10 is off, the deviation correction motor M4 is started to rotate in the depth direction. If the sensor S10 is turned on, the sensor S10 is moved to the front side, turned off, and then turned inward again to be stopped at the same time as the sensor is turned on, and the original is abutted against the width stopper plate 316 to correct the deviation and align. . The timer is set to turn on the bottom return clutch CL4 so that the front end of the document D1 is pinched by the pinching piece portion 311B of the feeding belt 311.

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.

(2S) Further, the bottom return feeding belt 311
Then, the offset correction roller pair 355 is rotated, and the document D1 is inserted below the upper document stack. Here, the separating lever 315A of the copy number separating means 315 is raised upward by a certain amount by the copy number separating solenoid SL4, and the sandwiching piece portion is provided.
The document D1 whose front end is nipped at 311B is inserted under the final untransported document (see FIG. 13F).

(2T) The document D1 is further sent out after the document replacement operation is completed, and the movable pressing plate 317 is lowered immediately after the registration is completed. Therefore, the document D1 being moved back to the document placing section 310 is moved down and moved. It passes over the pressing plate 317 and hits the document leading edge stopper 318 to stop.

(2U) When the document D4 is sent to the registration position, the rear end of the document D4 passes through the separating lever 315A,
The separating lever 315A moves upward, the copy number separating sensor S14 is turned on, and it is detected that the last document of the first circulation is sent out.

(2V) After the 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 S
The L3 is operated to move the separating lever 315 to the lower side of the document D4.
Insert A. 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,
The paper pressing lever 310Z provided on the upstream side of the separating lever 315A in the conveying direction assists the returning original document to be surely inserted under the original document bundle, and presses the original document lightly 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, and even pages are copied in the second cycle. Of course, the copying paper feeding operation on the copying machine main body 100 side is also the above RDH.
The movement is performed according to the mode and the R-RDH mode.

14 and 15 are for copying a double-sided original on both sides R
FIG. 6 is a schematic diagram showing a document conveyance process in a −RDH mode. The document conveyance for even-page copying of a small size document will be described below.

(3a) FIG. 14A shows a state in which the leading original D1 on the even-numbered page of the second cycle is conveyed intermediately. 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 out at a low speed (V0), and the registration roller 331 waits for registration (see FIG. 14B).

(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 after the trailing edge of the original D1 passes the registration sensor S7, the conveyor belt is conveyed. 341 is driven in the reverse direction and D1 is sent to the reverse path 336. The final document D4 in the first cycle is the discharge roller 3
The sheet is strongly nipped by 51, and is driven by the driving force of the sheet discharging motor M3 to resist the reverse conveying belt 341 and the sheet discharging passages f, j, and
It is conveyed at a high speed V1 in the direction of k. The document D1 is switched to the medium speed V2 before the completion of discharge, and at the time of this switching,
After being decelerated by the braking means BRK2, it is conveyed at a medium speed V2 for a predetermined time (see FIG. 14 (c)).

(3d) Subsequently, the document D1 is fed backward, is reversed through the path i, and reenters the platen glass 111 with the second surface facing downward. The document D4 advances toward the document placing section 310. The reversing detection sensor S17 turns off the predetermined time M2 for detecting 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 conveyance speed (V1) with a predetermined distance from D11 (see FIG.
14 (d), (e)).

(3e) The originals D1 and D2 are simultaneously conveyed (V1), and the original D1 is suddenly stopped at a predetermined position at the right end on the platen glass 111 and subjected to an exposure process. During this exposure process, the document D2 advances to a predetermined standby position on the platen glass 111 and is stopped. D3 is low speed V0 during D1 exposure
And stops at the position where it hits the registration roller 331 (see FIGS. 14 (f) and 15 (g)).

(3f) After the second surface of the document D1 is exposed, the document D1 is conveyed to the discharge reversing unit 350 at high speed V1. At the same time, the document D2 enters the platen glass 111 surface at high speed V1 (see FIG. 15 (h)).

(3g) The original D2 is turned upside down by the turning guide plate 336, and the platen glass 11 is turned downward on the fourth surface.
Enter 1 at one end with high speed V1. During this period, the first original D
1 passes through the reversing paths j, k, m, and n in the discharge reversing unit 350, and the first surface faces upward, and the speed V1 is applied to the document placing unit 310.
At high speed, and after sensor S9 detects the trailing edge of the document, V2
To proceed (see FIG. 15 (i)). Also, manuscript D2
After the registration sensor S7 is turned on for a predetermined time, the leading edge of the document feeds the waiting document D3 (V0).

(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 original D4 is sent out during the exposure of the original D2 and stops at the position where it abuts the registration roller 311. When the rear end of the original D1 passes the sensor S9, the original D1 advances toward the original end stopper 318 at the medium speed V2 as described above. (See FIG. 15 (j)).

In the same manner, the even-numbered page originals are reversed in the intermediate conveyance section 330, conveyed on the platen glass 111 with the even-numbered page face down, and switched back by the discharge reversal section 350 after the exposure processing. It is inverted and returned to the lowermost layer of the original stack on the original placing section 310 with the odd page surface facing upward (see FIGS. 15 (k) and 15 (l)).

The above-described small-size document feeding operation is as follows.
When conveying a large size document (B5 size, A3 size, 11 inch width paper) or the like, 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.
In the F mode, even when the image reading section discharges the sheet to the sheet discharge tray section 360 outside the apparatus by setting / switching the document discharge speed to V1> V2, the document is placed on the tray 361.363. Can be placed without scattering. In this example, V1 = 1200mm / s, V2 = 600mm / s
Is set to.

Some of the above-mentioned automatic document feeders set the image reading stop reference position of the document on the right end side of the platen glass 111 in the figure (on the side of the document discharge portion), 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.

Further, in this embodiment, the document pressing member 3100
Is pressed by its own weight, but a pressing force may be applied by a spring or the like. Further, the original pressing member 3100 may be fixed above the original return path without pressing the original curl. Furthermore, the protruding strip portion 311E having a high coefficient of friction on the feeding belt 311 may be substantially the entire width of the feeding belt 311 and a part between A and B in the conveying direction. Alternatively, three or more protrusions 311E may be arranged in parallel.

The feeding belt having the sandwiching piece and the movable pressing plate in the automatic document feeder according to the present invention are effective when applied to a recycle type automatic document feeder (RDH). The present invention can be widely applied to a sheet re-feeding device in which the sending sheet setting unit and the discharged sheet placing unit are the same.

[0123]

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 suction work 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.

Furthermore, by using a wide belt having a holding piece, it is effective to prevent the leading edge of the original from being damaged.

In particular, in the RDH mode or the R-RDH mode in the automatic document feeder of the present invention, the document discharged from the paper discharge reversing unit is returned to the bottom of the document stack on the feeding belt of the document placing unit. When doing this, the rough surface of the gripping piece of the feeding belt and the rough surface of the feeding belt surface hold the returned document securely regardless of the number of documents or curl, and at a high speed surely to the specified stop position. Can be delivered.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a copying machine equipped with a circulating 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 sectional view of a feeding belt and a partially enlarged sectional view thereof.

FIG. 6 is a front sectional view of a document placing section and a feeding section.

FIG. 7 is a side cross-sectional view of a separating unit, a pushing unit, and a document pressing portion of a feeding belt.

FIG. 8 is a schematic diagram showing a document conveying process in a document circulation mode on a document placing section.

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

FIG. 14 is a schematic diagram showing the first half of the even-numbered-page original conveyance process in the above mode.

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

[Explanation of symbols]

 100 Copying machine main body 110 Scanning exposure section 111 Platen glass (image reading section) 120 Image forming section 300 Circular automatic document feeder (RDH device) 310 Document placing part 3100 Document holding member 3101 Supporting part 3102 Document pressing part 3103 Guide part 310Z Paper presser lever 311 Feed belt 311A Seam part 311B Clamping piece part (gripper part) 311C Detection hole 311D Cutout part 311E Projection line part 312A Drive roller 314 Separation lever push-up means (push-up means) 314A Push-up lever 315 Separator 316 Width stopper plate 317 Movable pressing plate 318 Original document end stopper 319 Drive plate 320 Feed unit (paper feed unit) 321 Feed roller 324 Feed belt 330 Intermediate transport unit 331 Registration roller (first intermediate transport roller pair) 334 Registration roller (Second intermediate conveyance roller pair) 340 Conveyance section 341 Conveyor belt 350 Paper ejection reversing section 355 Circulation paper ejection roller (deviation correction roller) 360 Paper ejection tray a, b, c, d, e, i feed path f, g, h, j, k, m, n discharge path D, D1 to D5 original (original bundle)

Claims (2)

[Claims] 1. A document placing portion including a feeding belt for loading at least one set of a plurality of documents and moving the documents to a feeding start leading end position, and a document placing portion loaded on the document placing part. A paper feed unit that separates and feeds one of a plurality of originals and feeds it to the image reading unit, and the fed original is carried into the image reading unit. A circulating type automatic document feeder of a document top feed bottom returning system, comprising: a transport unit for carrying out and a discharge unit for discharging a document carried out from the image reading unit to the document placing unit, wherein the feeding belt A part of the original contacting surface of the original is formed as a strip-shaped protrusion that is long in the transport direction with respect to the other surface, the surface of the protrusion is formed as a rough surface having a high coefficient of friction, and an original that can be pressed against the protrusion. A circulating automatic document feeder, which is provided with a pressing member. 2. The pressure contact position of the document pressing member with the feed belt is set so that the document of the smallest size is pressure-contacted and fed until the document feed start leading end position is reached. The circulating automatic document feeder according to claim 1.