JPS63295330A - Document conveying device - Google Patents

Abstract

PURPOSE:To materialize an always proper document stopping position by starting the reverse direction travel of a conveying belt after detecting the stoppage of the normal direction travel of the belt, controlling the conveyance of a document based on a signal indicating that one end of the document passed through a defined position and a document size signal, and bringing the other end of the document into contact with the step part of a stopper board. CONSTITUTION:When a document is set to a both side copying mode, the document is sent to an inverting passage 43 when a defined count elapsed after detecting the rear end of the document by a sensor 18, and is sent out in the direction of a document glass 2 along an inverting inserting passage 42. At this time, a belt retainer roller 20 is rotated in a position far away from a stopper board 3 and a conveying belt 21 will not be slidingly brought into contact with the stopper board 3. Then, the approach of the front end of the document to the step part 3a of the stopper board is detected by the end of a defined count which is previously set according to the document passing signal and document size detecting signal of a rear end detecting sensor 48B. And, the restriction of the roller 28 is removed by this document approach signal and the belt 21 is stopped after one end of the document is brought into contact with the stopper board 3.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a document feeder used in a copying machine, and more particularly to an automatic document feeder having a mechanism for reversing a double-sided document.

[Background of the invention]

Conventionally, an original was constructed in such a way that the original was drawn onto the original glass using a conveyor belt that rotated forward and backward over the original glass, and then conveyed in the reverse direction so that the trailing edge of the original came into contact with the stepped part of a stopper plate provided at the edge of the original glass. A conveyance device was provided (Japanese Patent Application Laid-open No. 1983-
21762, Japanese Patent Application Laid-Open No. 61-229741)
.

In the case of this type of document feeder, only one sheet of the document placed on the tray of the document feeder is sent out from the document feeder, and the document is moved over the document glass in the forward direction of the first feed belt. It is fed by pressure and stops at a predetermined position. Here, the first side (front side) of the document is scanned and exposed to form a copy image on the recording paper.

The document that has completed the copying process on the mi side is moved over the document glass by the forward movement of the conveyor belt, and is sent to the paper discharge reversing unit.

When copying the fjIJ2 side (back side) of the original, the original is reversed inside the paper ejection reversing unit, and the original is sent onto the original glass again from the leading edge. Next, the conveyor belt is switched to run in the reverse direction by the reverse rotation of the reversible motor and the first driving roller, and the document is transported in the reverse direction on the document glass surface. When the leading edge of the document comes into contact with the stepped portion of the stopper plate provided at the edge of the document glass, the document conveyance is stopped.

After reaching this document stop position, the second side of the document is scanned and exposed, and a limited image is formed on the recording paper.

Thereafter, the conveyor belt is switched to forward travel, and the document is conveyed in the forward direction on the positive side of the document, passes through the discharge path of the discharge reversing unit, passes through the discharge opening, and is sent onto an external tray.

[Problem that the invention seeks to solve]

When a document is transported in the forward and reverse directions using the above document transport device, when the transport belt is switched from running in the reverse direction to running in the forward direction, slippage occurs between the drive roller that winds and drives the transport belt and the transport belt. occurs. This is because when document stop control is performed by counting pulses from the time of reverse rotation switching using an encoder installed on the rotating shaft of the reversible motor that rotates the drive roller, slipping of the conveyor belt causes an insufficient amount of document conveyance movement, and the document The leading edge does not reach the stepped portion of the stopper plate provided at the edge of the document glass. For this reason, the original document does not stop at a predetermined stopping position, that is, a copy positioning position, and correct copying is not performed.

[Means for solving problems]

The present invention is intended to solve the above-mentioned problem, and aims to always achieve a correct document stopping position regardless of slippage of the conveyor belt.

In order to achieve the above object, the document conveying device of the present invention includes:
A document conveying device configured to draw a document onto the document glass using a conveyance belt that runs forward over the document glass, and then convey it in the reverse direction so that one end of the document comes into contact with a step part of a stopper plate provided at the edge of the document glass. In , the forward running of the conveyor belt is stopped L:.

After detecting this, the scanner starts traveling in the reverse direction, and controls the document transport based on the signal detected by the sensor that the other end of the document being transported in the reverse direction has passed a predetermined position and the document size signal. The invention is characterized in that it is arranged such that one end of the document is brought into contact with the stepped portion of the stopper plate.

〔Example〕

Next, the present invention will be described based on embodiments shown in the accompanying drawings. FIG. 1 is an external perspective view of a copying machine equipped with a document conveying device. In the figure, 1 is a copy VCC tree body 5 is a document conveying device. The document conveying device 5 is installed on the document glass 2 on the main body 1 of the copying apparatus.

FIG. 2 is a sectional view of the document transport device 5 showing the document transport path. FIG. 3 is a perspective view showing the drive system of the document conveying device 5. As shown in FIG.

The document conveyance device 5 includes a conveyance unit 20 having a conveyance belt 21 capable of forward and reverse rotation on one surface of the original W@, f-lass 2.
, a paper feeding unit (rai+tq) 10 on one side of the original glass 2, a paper ejection reversing unit 40 above the other end of the original glass 2, and an ejection tray section 8 above the transport unit 20.
0. A frame 11 holding the paper feed unit 10 is screwed onto the copying machine main body 1, and is attached to the outer frame 1.
It is crowned by 2. The conveyance unit 20 and the paper discharge reversing unit 40 are housed and held in another housing 22, which is supported by the frame 11 and hinges, etc., and can be opened counterclockwise by holding the handle 22A on the right side in the figure. In the figure, the transport unit 20 and paper ejection reversing unit 40 are tilted to the right, and the document transport belt 21 is pressed against the document glass 2 placed on the top of the copying machine main body 1. It becomes.

The document conveyance device 5 according to the present invention is capable of automatically feeding a document using a conveyance mechanism described below.
Furthermore, by manually opening and closing the entire document conveying device 5, it also functions as a normal platen cover.

The paper feeding unit 10 includes a paper feeding section for separating and feeding the original document 1) on the document tray 13 one by one from the upper layer;
and a second paper feed section that supplies the document sent out by the first paper feed section to the conveyor belt 21.

First, a stack of originals to be copied is loaded on the original tray 13-H with the first page (front side) facing downward.

Next, when the copy button is pressed, the motor drive relay in the document conveyance device is turned on, and the motor M starts normal rotation. By this motor drive, the handling belt 15, paper feed roller 17
Both of the conveyor belts 21 start rotating forward (counterclockwise). At the same time, the paper feed solenoid is activated and
The movable guide plate 14 of the paper feeding section springs up and presses the originals stacked thereon against the sorting belt 15. The sorting belt 15 starts to rotate in the direction of the arrow, and as a result, the original mD is rotated between the sorting belt 15 moving at the same time and the sorting roller 1.
6, and only the outermost sheet of the stacked document bundle is sent out. When the tip of IW,m reaches near the paper feed roller 17 of the second paper feed unit rotating in the direction of the arrow, the paper feed solenoid is turned off by the detection signal of the sensor 18, and the movable guide plate 14 is lowered. , the feeding of subsequent originals is stopped, and only the previous original is transported by the paper feed roller 17.

The original document conveyed by the paper feed roller 17 passes above the Y-flange plate (scale plate) 3 that positions the rear end of the original document, and is fixed above the main body 1 of the copying machine. The conveyor belt 21 reaches the pressure contact position between the original document lath 2 and the conveyor belt 21 of the conveyor unit 20, and further rotates.
Conveyance continues due to the frictional force.

When the rear end of the document passes through the sensor 18,
The size of the document jam is automatically detected, and a paper jam (noyam) of the document jam in this conveyance path is detected.

The conveyor belt 21 includes a driving roller 23, a driven roller 24, and intermediate rollers 25A and 25B, which are rotatably supported by bearing plates fixed to both side walls of the camouflage belt 22.
The reversible motor M allows forward and reverse rotation. The upper running surface of the conveyor belt 21 is pressed by tension rollers 26A and 26B that are adjustable and supported by the bearing plate, and the lower running surface is pressed by a pressing roller 227A that is supported by a bearing member attached to the bearing plate.
, 27B, belt pressing roller 28, and separation roller 3
8 - FIGS. 4, tjS5, and 6 show the original photographing device 5.
FIG. 2 is a cross-sectional view, a plan view, and a perspective view showing the main parts near the drive roller 23 of FIG.

Among the rollers, a bearing member 29 that supports a belt holding roller (swing pack roller) 28 located near the drive row 223 is connected to a stopper plate (scale) fixed to the paper feed side end of the original lath 2. It is possible to move almost horizontally in conjunction with the running of the conveyor belt 21 between a position almost directly above the stepped portion 3a of the plate) 3 and a position to the right of that position, that is, in front of the sheet feeding direction (FIG. 4). It is composed of

FIG. 7 shows the belt pressing roller 28, the bearing member 29,
and a disassembled perspective view showing each shape of the restraining member,
Figure S8 and Figure FA9 are enlarged sectional views showing details of the shaft end portion 28a of the belt presser roller 28.

As shown in Fig. 156 and Fig.
The shaft end 28a of the belt presser roller 28 fits into the groove 2.
It is movable in the long axis direction of 9a.

A shaft support 29b protrudes from one lower end of the groove 81s29a and rotatably supports the shaft end 28a of the belt presser roller 28 to prevent it from falling downward. On the other hand, the other lower end of the groove 29a is cut out and has an opening 2.
9c is formed. When the shaft end 28a of the belt press roller 28 fitted into the groove 29a is moved to the vicinity of the opening, it can descend downward from the opening 29c.

Next, at the 2CI location in the intermediate portion near the shaft end 28a of the belt presser roller 28, there is provided a stage 1 with a slightly smaller diameter.
81) is formed, and the tip recess 30a of the five-motion arm 30 can be fitted into and removed from the stepped portion 281+.

The 4@ ends of the two swing arms 30 are screw-fixed near both ends of a swing shaft 31 having a prismatic shape. Both shaft ends 31a of this swing shaft 31 are fitted into holes of a hinge member 32 and are rotatably supported.

Near the center of the swing shaft 31, as shown in FIG.
A link plate 33 is fixed. An elongated hole 33a is provided at the other end of the link plate 33, and a shaft portion 34a at one end of an L-shaped swing lever 34 is slidably fitted into the elongated hole 33a.

The rotation center shaft portion 341) of the swing lever 34 has an integral shape protruding from both sides, and rotates by fitting into through holes in both side plates of a box-shaped holding plate 36 that fixedly holds the electromagnetic slide/id 35. freely held. This rotation center shaft portion 34I]
A torsion spring 37 is wound around the spring 37.
One end is hooked to a swing lever 34 and a holding plate 36, and the swing lever 34 is biased in one direction by a spring.

An elongated hole 34c is provided at the upper end of the swing lever 34, and a planter 35AL:r) of the electromagnetic slide/id 35 is provided in the elongated hole 34c, and a fixing pin 35B is implanted at the tip.
is slidably assigned.

Next, the operation of the belt pressing roller 28 will be explained using partial cross-sectional views of FIGS. 8(A), (B), and FIGS. 9(A) and (B).

One sheet of original 8%D sent out from the paper feed unit 10 is
The document plus 2 passes through the entrance formed by the gap between the conveyor belt 21 of the conveyor unit 20 and the stopper plate 3.
The paper reaches a pressure contact position with the conveyor belt 21, and conveyance is continued by the rotational frictional force of the conveyor belt 21.

In this document feeding and conveying process, when the conveyor belt 21 rotates counterclockwise (forward rotation), the belt presser roller 28 is in a state where it is not gripped by the swing arm 30 (t5
4 illustrations! ll! However, as the conveyor belt 21 travels, it slides into contact and moves to the right, moving away from the stepped portion 3a of the stopper plate 3. That is, the shaft end 28a of the belt presser roller 28 is rotated counterclockwise while the shaft end 28a of the belt presser roller 28 is rotated in the counterclockwise direction.
29a, and comes into contact with the right end surface of the groove 29a, and the rightward movement stops, but the driven rotation continues.

FIG. 4 and FIG. 8(B) show this state, and the shaft end 28a of the belt presser roller 28 is connected to the shaft support 2 of the bearing member 29.
It is fitted into and supported by the conveyor belt 9b, and rotates as a result of contacting the conveyor belt 21 without falling downward.

Next, the double-sided document conveying operation by the document conveying device having the belt pressing roller 28 will be described in detail based on the chart 70 in FIG. fjS10, the timing chart in FIG. 11, and the block diagram in FIG. 12.

Subsequently, the document mD is being conveyed by the conveyor belt 21 while sliding to the right on the lath 2. After the trailing edge of the original mD passes the paper trailing edge detection sensor 18, the trailing edge of the document reaches the stopper plate 3. After passing through, the sheet is further moved to the right over the document plus 2 by the normal rotation of the conveyor belt 21, and is fed into the sheet discharge reversing unit 40.

The paper ejection reversing unit) 40 includes a document ejection path and a document W.
A document reversing path for performing 4D front-back reversal is provided.

The paper discharge reversing unit 40 includes a delivery passage 41 consisting of an ID plate, etc., a reverse transfer input passage 42, and a reversal passage 43.4.
4, a paper ejection roller N46, a reversing roller pair 47, a document transport switching member 50, a paper leading edge detection sensor (paper ejection sensor) 48A, and a trailing edge detection sensor (reversing paper sensor) 48
It is composed of B.

On the other hand, when the rear end of the original fiD finishes passing the leading edge detection sensor 48A installed near the upper part of the pair of paper ejection rollers 46, the motor is driven after a predetermined count elapses from the detection signal from the leading edge detection sensor 48A. relay is activated and the forward rotation of motor M is temporarily stopped. This conveyor belt 21
The forward direction of the vehicle will also be temporarily stopped. Even after this motor stop signal is input, the motor drive shaft rotates slightly due to inertia, and an encoder E directly connected to the drive shaft counts inertia pulses until the motor stops.

The interval between inertial pulses due to this reduction in the rotational speed of the drive shaft is 10
If the period exceeds 16 seconds, a specified short period of time (for example, 100
During the process, the conveyor belt 21 is temporarily stopped.

After the predetermined short time has elapsed, a reverse rotation ON signal is input to the motor M, and the motor M starts rotating in reverse.

As a result, the rotation of the conveyor belt 21 is switched between clockwise and reverse rotation. Note that the path length of the reversing portion from the leading edge detection sensor 48A to the trailing edge detection sensor 48B is set in advance to be sufficiently longer than the maximum length of each type of element fJsD used.

Immediately before the reverse transfer row of the conveyance belt 21 is started, a signal is input to the electromagnetic solenoid 35 after the sensor 48A detects the trailing edge of the document. As a result, the plunger 35
A is sucked, and the fixed bottle 35B of the plunger 35A is
It engages with the elongated hole 34c of the swing lever 34 and swings the swing lever 34 clockwise about the fixed central shaft portion 34b.

Along with this, the shaft ff534 at the other end of the swing lever 34
Since a is engaged with the elongated hole 33a of the link plate 33,
The clockwise swing of the swing lever 34 is caused by the movement of the integrated link plate 33! The I'JJ pongee 31 and the swinging arm 30 are swung 5h counterclockwise around both sleeve ends 33a. This counterclockwise swing causes the recess 3 of the swing arm 30 to
0a is assigned to and gripped by the stage A 1 part 281) of the belt press roller 28, restricts the horizontal movement of the belt press roller 28, and holds the belt press roller 28 rotatably.

FIG. 6 and FIG. 9(A) are a perspective view and a partial sectional view of the document conveying device showing this state.

When setting the double-sided copy mode of the original IHD, the sensor 18
After a predetermined count has elapsed after detecting the trailing edge of the document,
When the solenoid is energized, the document conveyance switching member 50 that operates in conjunction with the solenoid is swung counterclockwise as shown in FIG. The original document conveyed from the upper pressure contact position of 46 is guided to the lower left. This original document is sent to the reversing path 43, makes a U-turn again at the reversing roller pair 47, passes through the reversing path 44, passes the downward pressure contact position of the paper ejection roller pair 46, and continues along the reversing insertion path 42. 〃It is sent out in the direction of lath 2.

In this way, )1! of the conveyor belt 21! During the transfer process, the belt holding roller 28 is hung on the swinging arm 30.
-, and rotates at a position away from the stopper plate 3, and the conveyor belt 21 does not come into sliding contact with the stopper plate 3, so the conveyor belt 21 will not be damaged or broken by friction.

The original paper is reversed by passing through the reversing path of the paper ejection reversing unit 40, and the back side, that is, the second side is used as the original.
The document is sent out onto a glass 2'' facing the upper surface of the glass 2, and is further conveyed by a conveyor belt 21.

When the rear end of the original w@D passes through the rear end detection sensor 48B, the motor drive relay is actuated by this rear end detection signal, and the reverse rotation of the motor M is temporarily stopped. As a result, the reverse running of the conveyor belt 21 is temporarily stopped, and the rotation of the belt press roller 28, which is in sliding contact with the conveyor belt 21 and rotates as a result, is also stopped.

(See Figures 6.8(A) and 9(A)) After the rotation of the belt holding roller 28 has stopped, a drive signal is input to the solenoid 35, and the restriction on the axis position of the belt holding roller 28 is released.

The belt pressing roller 28 after this restriction is lifted is shown in Fig. 8 (A
As shown in the figure, the shaft end 28a is placed on each shaft support 291) of the bearing member 29, and is rotated by the conveyor belt 21 in the two-way position. Therefore, the lower surface of the conveyor belt 21 in pressure contact with the belt pressing roller 28 is separated from the upper surface of the document glass 2 with a slight gap g formed below the pressure contact position.

That is, the pressure rollers 27A, 27B, the separation roller 38
The conveyor belt 2 is pressed against the top surface of the original glass 2 by
1 is a belt pressing roller 28 located near the stopper plate 3;
Since it is in a non-contact state at the position , the leading edge of the II2 line of the document conveyed in the direction of the stopper plate 3 by the reverse transfer line of the conveyor belt 21 touches the step G of the stopper plate 3 due to excessive conveyance pressing force. 3. There is no possibility of problems such as edge folding of the document, wrinkles, or poor copy positioning due to strong contact with a.

The approach of the leading edge of the original 8% D to the stepped portion 3a is detected by setting a predetermined count based on the document passing signal and document size detection signal of the trailing edge detection sensor 48B, and by this count up. .

Based on this document approach signal, a signal is input to the electromagnetic solenoid 35, and the plunger 35A protrudes after the conveyor belt 21 is temporarily stopped in reverse rotation due to the continuous rotation of the motor being temporarily stopped and the driven rotation of the belt presser roller 28 is stopped. As a result, the swing lever 34 swings counterclockwise around the rotation center shaft 34b, and the swing arm 30 is rotated clockwise around the swing shaft 31 via the link plate 33 that engages with the swing lever 34. Since it is swung in the direction and flipped up, the engagement between each day 130a of the swinging arm 30 and the stepped portion 28b of the belt presser roller 28 is released, and the shaft position restriction of the belt presser roller 28 is released and the belt can be moved. Become.

The belt presser roller 28 is deregulated while the conveyor belt 21 is temporarily stopped in reverse due to the temporary stop of the motor reverse rotation, and after a short period of time, the relay for driving the motor is activated again and the reverse rotation of the motor M is resumed. The conveyor belt 21 starts running in reverse again.

The roller surface 28c of the belt presser roller 28, which is in sliding contact with the inner surface of the conveyor belt 21 that is moving in the reverse direction, is movable.
I! IJ and rotates clockwise, and the shaft end 28
A is guided by each groove 29n of the bearing member 29 and transferred, and is pulled leftward and approaches the vicinity of the left end surface of the groove 29a.

When the belt presser roller 28 is moved to the left, its shaft end 28n separates from each groove 2'J of the bearing member 29 and falls into the lower opening 29c, as shown in FIG. 8(B). Move to a certain position.

FIG. 9(B) is a partial sectional view of the document conveyance path showing this state. This illustration? ! Here, the conveyor belt 21 is pressed from the back side by the roller surface 28c of the belt presser roller 28, and the front side of the conveyor belt 21 is pressed against the stepped portion 3a of the stopper plate 3.
Since the document is lightly pressed against and closes the gap g, the leading edge of the document conveyed in the reverse direction reliably comes into contact with the stepped portion 3a of the stopper plate 3 and stops, and does not enter the paper feeding unit side. After one end of the original fiD comes into contact with the stopper plate 3, the motor drive is stopped, the reverse rotation of the conveyor belt 21 is stopped, and the original document tray is stopped.

The original placed at this precise stop position is pressed onto the original glass 2 by the conveyor belt 21 under pressure from the plurality of suppression rollers 27A and 28B, and exposure of the second side (back side) is started. After that, an image is formed and transferred to recording paper through a well-known process to complete one-sided copying. At this time, the image position on the recording paper and the original image position on the document are accurately maintained.

When the exposure of the back side of the original is completed, the conveyor belt 21 rotates in the normal direction, and the original! r@D is fed into the paper ejection reversing unit 40 through the delivery path 41, passes through the paper ejection roller pair 46, reversing paths 43, 44, and reversing roller pair 47, and is transferred from the reversing insertion path 42 onto the document glass 2. is transported in reverse. At this point, the conveyor belt 21 performs a reverse transfer row, and during this time, the belt pressing roller 28 is regulated by the slip/id 35. In addition, the temporary stop just before the end of the reverse transfer line and the release of the restriction on the belt presser roller 28 are performed in the same manner as described above.

In this way, it is conveyed onto the original 8% glass 2, and the stopper plate 3
When the original document is stopped at a predetermined position with its leading end abutted against the stepped portion 3a, the first side (front surface) of the original document is exposed to light, and an image forming process is performed within the main body of the copying apparatus.

When the exposure of the back side of the document sheet is completed, the conveyor belt 21 rotates in the forward direction, and the document fwD is transferred from the feed path 41 to the document conveyance switching member in a state where it is sandwiched between the paper ejection roller pair 46 and the reversing path is closed. The discharge passage 45 passes through the upper surface of the discharge passage 50.
The documents are then sent onto the discharge tray section 80, and as the copying is repeated, the documents are successively stacked.

FIG. 13(A) is a diagram showing the document passage route, and the dashed line indicates the route. According to this conveyance device, the document tray of the feeding unit 10 is placed on the stand 13, and the stack of documents is placed with the front side (12 sides) of the document 1jS1 page (Dl) facing down. do. Then, the original iD is fed from the last page (for example, D6), the back side D6B of the original D6 is copied after being reversed, the front side D6A of the original mD6 is copied after being reversed again, and the original is placed on the output tray 80. The surface D6A of D6 is placed facing upward.

Subsequently, the next original document D5 is transported and copied, and the next document D5 is transferred to the output tray 80.
is placed on top of the original MD6.

All the originals that have been copied in this way are delivered to the output tray 8.
The first page (Dl) is aligned and 8t@ on top of page 0 with the front surface (DIA) facing upward.

The document conveying device of the present invention can also be set to a copy mode for only the first side of the document. FIG. 13(B) is a diagram showing the document conveyance path in this case, and the dashed line is the document passage path. Furthermore, the area within the circular broken line is a partially enlarged view illustrating the document stacking state.

In the document tray of the paper feed unit 10, the stack of documents stacked on the table 13 is placed with the first page as the bottom layer and the first page (front side) is facing down, and the document tray is placed on the document tray 13 with the first page (front side) facing down. ) 40 and is discharged to the discharge tray section 80. At this time, the original document does not pass through the reversing passages 43, 44 and the reversing insertion passage 42, but passes through the delivery passage 41, the pair of paper ejection rollers 46, and then from the paper ejection passage 45 to the ejection tray section 80. Further, the regulating operation of the swinging arm 30 by the solenoid 35 does not operate on the belt presser row 228 at the entrance of the conveyance unit 20, and the roller 28 slides in contact with and follows the forward and reverse rotation of the conveyance belt 21. And it is movable left and right by a bearing member 29.

The document which is being conveyed by sliding to the right on the document plus 2 by the conveyance bell) 21 passes the paper trailing edge detection sensor 18, and then the rear end of the document passes the stopper plate 3. After that, it overruns slightly and stops temporarily. This is determined by counting up a clock pulse value set according to the length of the detected document size, starting from the generation of the trailing edge detection signal sent to the sensor 18.

At this point, the drive signal for normal rotation of motor M is turned off.
Then, a start signal is applied to the motor to drive it in reverse.

When the motor M starts to drive in the reverse direction, the conveyor belt 21 starts running in the reverse direction, causing the overrun document tray to move backward, and after the motor M is rotated in the reverse direction by a predetermined pulse, the rear end of the document sheet is placed at the stopper plate. 3, the conveyor belt 21 stops running.

When the conveyor belt 21 runs in reverse, the belt pressing roller 28 whose shaft end is movable is rotated clockwise by the frictional tension of the circumscribing conveyor belt 21, and the shaft end 28a is rotated by the bearing member. 29 along the groove 29a to the left. and belt presser roller 2
When the roller 28c of No. 8 is located on the one L side closest to the stepped portion 3a of the stopper 3, the shaft end portion 28a of the belt presser roller 28 comes into contact with the left end surface of the groove portion 29a of the bearing member Z9. Only driven rotation is possible. At this leftmost position,
The belt pressing roller 28 comes into light pressure contact with the stepped portion 3al of the stopper plate 3 via the conveyor belt 21, thereby closing the gap g.

The leading edge of the original WSD, which is being fed in the reverse direction, reliably hits near the stepped portion 3a of the stopper 3 in this closed state, and as the transport belt 21 stops running, the document tray is placed at an accurate stopping position. In other words, original paper is completely prevented from entering the paper feed unit 10 through the gap.

The document placed at this precise stop position is pressed onto the document lath 2 by the conveyor belt 21 under pressure from the plurality of pressure rollers 27A, 27B and separation roller 38, and the first side (front surface) is exposed. After that, an image is formed and transferred to recording paper through a well-known process, and one-sided copying is completed. At this time, the image position on the recording paper-1 and the original image position on the document are accurately maintained.

The document which has completed the copying process on the first side is moved rightward on the document glass 2 by the normal rotation of the conveyor belt 21 and is sent to the paper discharge reversing unit 40 .

Original 1") +, t Due to the conveying force of the Wl transport belt 21, the original glass 2 enters the delivery path 41 from the right end of the original glass 2, removes it in the negative direction, makes a U turn, and is pressed and clamped to the upper position of the IP paper roller pair 46, and then left The original is ejected outward from the other ejection path 45 and placed on the original ejection tray 80 with the first side facing upward.At this time, the original transport switching member 50 is lowered and placed on the side of the ejection center roller 46A. The original 1r7 is pushed into the paper discharge path.

The stacking order of the bundle of originals stacked on the table 13-H of the original document receiver and the stacking order of the originals discharged onto the discharge tray section 80 are both the same as in the double-sided original copying mode described above.

〔Effect of the invention〕

As described above, in the present invention, after the original is drawn into the original rasuhi by the conveyor belt that runs the original rasuhi in the forward direction,
In a document conveying device configured to convey the document in the reverse direction and bring the leading edge of the document into contact with a stopper plate stepped portion provided at the edge of the document backing, the conveyor belt starts traveling in the reverse direction after detecting that the forward direction of the conveyance belt has stopped. Then, the document transport is controlled based on a signal detected by a sensor that the trailing edge of the document being conveyed by this reverse direction has passed a predetermined position and the document size signal, and the leading edge of the document is moved to the stopper plate stage. Since the document is brought into contact with the document portion, the document can be positioned accurately and reliably.

In particular, since the document stopping position is controlled by the document trailing edge detection means, the distance the document travels from the time of detection until the document leading edge reaches the stopper plate stage is relatively small. Control is performed accurately, and the document does not stop at a predetermined position due to overrun or insufficient travel.

In addition, poor document conveyance due to slip between the drive roller and the conveyor belt that occurs when the motor is switched between forward and reverse directions can be resolved by temporarily stopping the conveyor belt and by controlling the trailing edge of the document.

[Brief explanation of drawings]

FIG. 1 is an external perspective view of a copying machine equipped with a document conveying device according to the present invention. FIG. PtS2 is a sectional view of the document conveyance device showing the document conveyance path. Figure 3 shows the i
It is a perspective view showing a dynamic system. 4, Pt55, and PtS7 of FIG. 6 are a sectional view, a plan view, a perspective view, and an exploded perspective view showing the main parts near the drive roller of the document conveying device. FIGS. 8(A) and 8(B) are enlarged sectional views showing details of the shaft end of the belt presser roller. FIGS. 9(A) and 9(B) are partial sectional views illustrating the regulating and releasing states of the belt pressing roller. FIGS. 10 and 11 are a flow chart and a timing chart explaining the document conveyance process, and FIG. 12 is a block diagram showing control of the document conveyance device. FIGS. 13A and 13B are diagrams showing conveyance paths for double-sided originals and single-sided originals. 1...Copying device main body 2...Original glass 3.
...Stopper plate 3a...Step part 5...Document conveyance device 10...Paper feed unit 20...Conveyance unit 21...Conveyance belt 23...Drive rollers 27A, 27B... Suppression roller 28...Belt press roller 28a...Shaft end 28c...Roller surfaces 29A, 29B...Bearing member 29a...Groove 2
9b...Axis support 29cm opening 30A
, 30B... Swinging arm 30a... Recessed portion 31...
・Swinging shaft 32A, 32B... Hinno shaft 33... Link plate 34... Swinging lever 3
5... Electromagnetic solenoid 36... Holding plate 38.
...Separation roller 40...Sheet discharge reversing unit 46...Sheet discharge roller pair 47...Reversing roller pair 48A...Tip detection sensor (sheet discharge sensor) 48B
. . . Trailing edge detection sensor (reversed paper sensor) 50 . . . Document conveyance switching member 80 . . . Ejection tray section, D 1.
D2. D3. D4. D5. D6...Document g...Gap

Claims (1)

[Claims] A document conveying device configured to draw a document onto the document glass using a conveyance belt that runs forward over the document glass, and then convey it in the reverse direction so that one end of the document comes into contact with a step part of a stopper plate provided at the edge of the document glass. , after detecting that the conveyor belt has stopped traveling in the forward direction, it starts traveling in the reverse direction;
The conveyance of the document is controlled based on a signal detected by a sensor that the other end of the document conveyed by this reverse direction has passed a predetermined position and a document size signal, and one end of the document is moved to the step of the stopper plate. A document conveying device characterized in that the document conveying device is brought into contact with the document conveying device.