JP2521473B2 - Document feeder - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a document feeder used in a copying machine, and more particularly to an automatic document feeder having a double-sided document front / back reversing mechanism.

[Background of the Invention]

Conventionally, a document is configured so that a document is drawn onto the document glass by a conveyor belt that rotates forward and backward on the document glass and then is conveyed in reverse to bring the rear end of the document into contact with a step portion of a stopper plate provided at the edge of the document glass. A carrier was provided. In the case of this type of document feeder, when feeding a document from the document feeder, make a gap between the transport belt and the stopper plate step on the edge of the document glass to allow the document to pass, and reverse the document. When the sheet is conveyed and abutted against the stepped portion of the stopper plate, it is necessary that the gap be closed. As a means for this, in Japanese Patent Laid-Open No. 58-21762, a belt pressing roller is pivotally supported at the swing end of a lever that can swing in the vertical direction about the shaft of the drive roller of the conveyor belt as a fulcrum and the lever swings. It has been shown that the end side is biased downward by a spring, the roller is moved upward against the spring when the conveyor belt rotates in the forward direction, and the roller is moved downward by using the spring force during the reverse rotation.

[Problems to be solved by the invention]

However, in the above case, the mechanism is complicated, and the relative position between the drive roller shaft of the conveyor belt and the stopper plate step is important for the installation position of the belt pressing roller.
If this was not set accurately, the above functions could not be fully exhibited. Further, in the above case, when the spring force of the spring for urging the belt pressing roller downward is strong, it is difficult to form the gap when the conveyor belt rotates in the forward direction, and when it is weak, the effect of closing the gap is lost and its adjustment is difficult. Met.

In order to solve the above problems, the present applicant has previously disclosed a new document feeder in Japanese Patent Application Laid-Open No. 61-229741. In this document feeder, a document is drawn onto the document glass by a conveyor belt that rotates forward and backward on the document glass, and then the document is conveyed backwards so that the trailing edge of the document is brought into contact with a stopper plate stepped portion provided at the edge of the document glass. In the configured document conveying apparatus, a belt pressing roller that moves in association with forward and reverse rotation of the conveying belt is provided near the stopper plate step portion.

In this document feeder, when the document is conveyed by reversing the conveyor belt, the belt pressing roller is always in pressure contact with the step portion of the stopper plate via the conveyor belt, which not only causes rotation of the conveyor belt but also causes rotation failure. The transport belt is rubbed against the stepped portion of the stopper plate and is scraped off, which causes breakage of the transport belt.

[Means for solving problems]

The present invention is intended to solve the above-mentioned problems, and can reliably form and close the gap between the conveyor belt and the step portion of the stopper plate with a simple structure, and further, the driving roller and the stopper. The purpose of the present invention is to provide a document feeder that is not affected by the relative conditions with respect to the plate step portion, and particularly when the document is reversely conveyed by reverse rotation of the conveyor belt, the document does not hit the stopper plate step portion accurately and does not pass through, and The purpose of the invention is to prevent running defects and breakage.

In order to achieve the above object, the document feeder according to the present invention draws an original onto the original glass by means of a conveying belt that runs forward and backward on the original glass, and then conveys the original in the opposite direction so that the original edge is provided on the original glass edge. In a document feeder configured to be brought into contact with the stopper plate step portion, a belt pressing roller that moves in response to forward / reverse running of the conveyor belt and a belt pressing roller are provided in the vicinity of the stopper plate step portion. And a regulating means constituted by a latching member which is latched at a predetermined position apart from the stopper plate step portion, and the document is conveyed near the stopper plate step portion when the document is conveyed in the reverse rotation of the conveying belt. By operating the means, the hooking member releases the hooking with the belt pressing roller for pressing the belt, and the belt pressing roller reversely travels. Go to stop Itadan part direction by the frictional force of, is characterized in that so as to abut the original on the original glass stopper plate stepped portion.

〔Example〕

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

FIG. 2 is a sectional view of the document feeding device 5 showing the document feeding path. FIG. 3 is a perspective view showing a drive system of the document feeder 5.

The document feeding device 5 includes a feeding unit 20 having a feeding belt 21 capable of reversing forward and backward on the upper surface of the original glass 2, a paper feeding unit 10 at one end of the original glass 2, and the other end of the original glass 2. A paper output reversing unit 40 on the upper side and a discharge tray section 80 above the transport unit 20 are provided. A frame 11 holding the paper feeding unit 10 is screwed to the copying apparatus main body 1 and is covered with an exterior frame 12. The transport unit 20 and the paper output reversing unit 40 are housed and held in another housing 22, and the housing 22 is supported by the frame 11 and a hinge, etc., and has a structure that can be opened counterclockwise by holding a handle 22A on the right side in the drawing. However, in the case of the figure, the transport unit 20 and the paper discharge reversing unit 40 are tilted to the right, and the document transport belt 21 presses the document glass 2 placed on the upper part of the copying apparatus main body 1. There is.

The document feeder 5 according to the present invention enables automatic feeding of a document by a feeding mechanism described below. However, by manually opening and closing the document feeder 5 as a normal platen cover. It also has functions.

The paper feed unit 10 supplies a first paper feed section for separating and sending out the originals D on the original tray 13 one by one from the upper layer, and the originals sent by the first paper feed section to a conveyor belt 21. It is composed of a second sheet feeding section.

First, copy the original stack to be copied on page 1 page 1 (front side)
Is placed on the original receiving tray 13 with the side facing down.

Next, when the copy button is pressed, the motor drive relay in the document feeder is turned on, and the motor M starts to rotate normally. By this motor drive, the separating belt 15, the paper feed roller 17, and the transport belt 21 all start forward rotation (counterclockwise travel). At the same time, the sheet feeding solenoid is operated, and the movable guide plate 14 of the first sheet feeding portion bounces up, and the documents D stacked on the movable guide plate 14 are pressed against the separating belt 15. Judgment belt 15
Starts rotating in the direction of the arrow, whereby the document D is squeezed by the rotating separating belt 15 and the separating roller 16, and only the uppermost one of the accumulated document bundle is sent out. When the leading edge of the original reaches the vicinity of the paper feed roller 17 of the second paper feed unit that rotates 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 descends, The document feeding is stopped, and only the preceding document is conveyed by the sheet feeding roller 17.

The original document D conveyed by the paper feed roller 17 passes above the stopper plate (scale plate) 3 for positioning the rear end of the original document D, and is fixed above the copying apparatus main body 1. Glass 2 and conveyor belt for conveyor unit 20
The conveyance is continued by the frictional force of the conveyance belt 21 which reaches the pressure contact position of 21 and rotates further.

By passing the rear end of the document D through the sensor 18,
The size of the document D is automatically detected, and a paper jam (jam) of the document D in this conveyance path is also detected.

The conveyor belt 21 includes a drive roller 23, a driven roller 24, an intermediate roller 25A, and an intermediate roller 25A, which are rotatably supported by bearing plates which are bearing members fixed to both side wall portions of the housing 22.
It is stretched between 25B and can be rotated forward and backward by a reversible motor M. The rear running surface of the conveyor belt 21 is pressed by tension rollers 26A, 26B adjustably supported by the bearing plate, and the lower running surface is pressed by a bearing roller 27A, which is supported by a bearing member mounted on the bearing plate. 27B,
It is pressed by the belt pressing roller 28 and the separating roller 38.

4, 5, and 6 are a cross-sectional view, a plan view, and a perspective view showing the main part in the vicinity of the drive roller 23 of the document feeder 5.

Among the rollers, a bearing member 29 for supporting a belt pressing roller (swing back roller) 28 near the driving roller 23 is a stopper plate (scale plate) which is fixed to the end of the original glass 2 on the sheet feeding side. ) In order to be able to move substantially horizontally between the position almost immediately above the stepped portion 3a of 3 and the position to the right of that position, that is, the position in front of the sheet feeding direction (FIG. 4), in conjunction with the running of the conveyor belt 21. It is configured.

FIG. 7 is an exploded perspective view showing the shapes of the belt pressing roller 28, the bearing member 29, and the restraining member, and FIGS. 8 and 9 show the details of the shaft end portion 28a of the belt pressing roller 28. It is an expanded sectional view.

As shown in FIGS. 6 and 7, the bearing member 29 has notched oval grooves 29a, respectively, and the shaft end 28a of the belt pressing roller 28 is fitted into the grooves 29a so that the groove 29a It is movable in the long axis direction.

At the lower end of the groove 29a, the belt pressing roller 28
A shaft support portion 29b that rotatably supports the shaft end portion 28a and prevents the shaft end portion 28a from falling is projected. On the other hand, the other lower end of the groove 29a is notched to form an opening 29a. Shaft end portion 2 of the belt pressing roller 28 fitted in the groove portion 29a
When 8a is moved to the vicinity of the opening, the opening 29
It is possible to descend from c.

Next, a stepped portion 28b having a slightly smaller diameter is formed at two places in the intermediate portion near the shaft end portion 28a of the belt pressing roller 28, and the stepped portion 28b has a recessed portion at the tip of the swing arm 30. 3
0a can be fitted and removed freely.

The other ends of the two rocking arms 30 are fixed by screws near both ends of a rocking shaft 31 having a prismatic shape. Both shaft end portions 31a of the swing shaft 31 are fitted into the holes of the hinge member 32 and are rotatably supported.

In the vicinity of the center of the swing shaft 31, as shown in FIG.
The link plate 33 is fixed. An elongated hole 33a is provided at the other end of the link plate 33 to form an L-shaped swing lever 3
A shaft portion 34a at one end of 4 is slidably fitted in the elongated hole 33a.

The rotation center shaft portion 34b of the swing lever 34 has an integral shape protruding to both sides, and is fitted into the through holes of both side plates of the box-shaped holding plate 36 for fixedly holding the electromagnetic solenoid 35 and rotatably held. Has been done. A torsion spring 37 is wound around the rotation center shaft portion 34b, and one end of the spring 37 is hooked by a swing lever 34 and a holding plate 36, and the swing lever 34 is biased in one direction by a spring. Has been done.

An elongated hole 34c is provided at the upper end of the swing lever 34, and a fixed pin 35B planted at the tip of the plunger 35A of the electromagnetic solenoid 35 is slidably fitted into the elongated hole 34c. .

Next, the operation of the belt pressing roller 28 will be described with reference to partial sectional views of FIGS. 8 (A), (B), 9 (A) and (B).

One sheet of the document D sent out from the sheet feeding unit 10 passes through an entrance formed by a gap between the transport belt 21 of the transport unit 20 and the stopper plate 3, and is further separated between the document glass 2 and the transport belt 21. After reaching the press contact position, the conveyance is continued by the rotational frictional force of the conveyance belt 21.

In this document feeding and conveying process, when the conveying belt 21 rotates counterclockwise (forward rotation), the belt pressing roller is moved.
28 is held in a state where it is not gripped by the swing arm 30 (state shown in the fourth diagram) and is movable, but it slides into contact with the traveling of the conveyor belt 21 and shifts to the right, Move away from the step 3a of the stopper plate 3. That is, the shaft end portion 28a of the belt pressing roller 28 rolls to the right along the groove portion 29a of the bearing member 29 while being driven to rotate in the counterclockwise direction, and the groove portion 2
It contacts the right end face of 9a and stops shifting to the right, but is driven to rotate.

FIGS. 4 and 8B show this state, in which the shaft end portion 28a of the belt pressing roller 28 is fitted into and supported by the shaft supporting portion 29b of the bearing member 29, and the conveyor belt does not descend downward.
It comes into contact with 21 and is driven to rotate.

Next, a double-sided document feeding operation by the document feeding device having the belt pressing roller 28 will be described with reference to the flowchart of FIG.
Details will be described based on the timing chart of FIG. 11 and the block diagram of FIG.

Subsequently, the original D, which is being conveyed by sliding rightward on the original glass 2 by the conveying belt 21, passes its trailing edge through the sensor 18 for detecting the trailing edge of the sheet, and then the trailing edge of the original D moves through the stopper plate 3. After passing, the transport belt 21 is further rotated in the forward direction to move to the right on the original glass 2 and is sent to the paper discharge reversing unit 40.

The discharge reversing unit 40 is provided with a discharge path for the document D and a document reversing path for reversing the front and back of the document D.

The paper discharge reversing unit 40 includes a feed passage 41 formed of a guide plate and the like, an anti-transfer entrance passage 42, reversing passages 43 and 44, a paper discharge roller pair 46, a reversing roller pair 47, and a document conveyance switching member 50.
And a paper front end detection sensor (paper discharge sensor) 48A and a rear end detection sensor (reversed paper sensor) 48B.

On the other hand, when the trailing edge of the document D has finished passing the leading edge detecting sensor 48A installed near the pair of discharge rollers 46, after a predetermined count has passed from the detection signal from the leading edge detecting sensor 48A, the motor is driven. The relay operates to temporarily stop the normal rotation of the motor M. As a result, the forward running of the conveyor belt 21 is also temporarily stopped. Even after this motor stop signal is input, the motor drive shaft slightly rotates due to inertia, and the encoder E directly connected to the drive shaft counts the inertial pulse until the stop. During a predetermined short time (for example, 100 ms) from the moment when the interval of the inertial pulse due to the decrease in the rotational speed of the drive shaft exceeds 10 ms,
The conveyor belt 21 is temporarily stopped. After the lapse of the predetermined short time, the reverse rotation ON signal is input to the motor M, and the reverse rotation is started.

As a result, the rotation of the conveyor belt 21 is switched clockwise (reverse rotation). The path length of the reversing portion from the leading edge detecting sensor 48A to the trailing edge detecting sensor 48B is set to be sufficiently longer than the maximum length of various documents D used in advance.

Immediately before the reverse transfer of the conveyor belt 21 is started, after the document trailing edge is detected by the sensor 48A, the electromagnetic solenoid 3
The signal is input to 5. As a result, the plunger 35A is sucked, and the fixed pin 35B of the plunger 35A engages with the elongated hole 34c of the swing lever 34 to swing the swing lever 34 clockwise around the fixed center shaft portion 34b. .

At the same time, since the shaft portion 34a at the other end of the swing lever 34 is engaged with the elongated hole 33a of the link plate 33, the swing lever 34
The clockwise swinging causes the link plate 33, the swinging shaft 31, and the swinging arm 30, which are integrated, to swing counterclockwise about both shaft end portions 33a. By this counterclockwise swinging, the recess 30a of the swinging arm 30 is fitted into and gripped by the stepped portion 28b of the belt pressing roller 28, restricts the lateral movement of the belt pressing roller 28, and rotatably holds it.

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

When the double-sided copy mode of the document D is set, the solenoid 18 is energized after a predetermined count has passed after the document trailing edge is detected by the sensor 18, and the document transport switching member 50 which is interlocked with the solenoid is rotated counterclockwise as shown in FIG. Swing to the paper ejection path 45
While closing the side, the lower surface of the switching member 50 guides the document D conveyed from the upper pressure contact position of the paper discharge roller pair 46 to the lower left. This document D is sent to the reversing path 43, and makes a U-turn again by the reversing roller pair 47 to pass through the reversing path 44,
Pass the lower pressure contact position of the pair of discharge rollers 46 and pass through the reverse insertion path.
It is sent out toward the original glass 2 along 42.

Thus, during the reverse transfer of the conveyor belt 21, the belt pressing roller 28 is hooked on the swing arm 30,
It rotates at a position away from the stopper plate 3 and the conveyor belt
Since 21 does not make sliding contact with the stopper plate 3, the conveyor belt 21 is not frictionally damaged or broken.

The document D is turned upside down by passing through the reversing path of the sheet discharge reversing unit 40, and is sent out onto the document glass 2 with its back surface, that is, the second surface facing the upper surface of the document glass 2, and further conveyed by the conveyor belt 21. Transported.

When the trailing edge of the document D passes through the trailing edge detection sensor 48B, the trailing edge detection signal activates the motor driving relay to temporarily stop the reverse rotation of the motor M. As a result, the reverse rotation of the conveyor belt 21 is temporarily stopped, so that the belt pressing roller 28, which is in sliding contact with the conveyor belt 21 and is driven to rotate, is also stopped. (Refer to Fig. 6, 8 (A), 9 (A)) After the belt pressing roller 28 stops rotating, the solenoid
A drive signal is input to 35, and the axial position regulation of the belt pressing roller 28 is released.

As shown in FIG. 8 (A), the belt pressing roller 28 before the release of the regulation is driven by the conveyor belt 21 to rotate at the upper position where the shaft end 28a is placed on each shaft support 29b of the bearing member 29. There is. Therefore, the lower surface of the conveyor belt 21 that is in pressure contact with the belt pressing roller 28 is separated from the upper surface of the original glass 2 with a slight gap g below the pressure contact position. That is, the conveyor belt 21 pressed against the upper surface of the original glass 2 by the pressing rollers 27A, 27B and the separating roller 38 is the belt pressing roller in the vicinity of the stopper plate 3.
Since it is in a non-contact state at the position of 28, the running front end of the document D conveyed in the direction of the stopper plate 3 by the reverse transfer of the conveyor belt 21 has a stepped portion of the stopper plate 3 due to excessive conveyance pressing force. It strongly hits 3a, and the ears of the original are broken,
No problems such as wrinkles and improper positioning of copying occur.

The approach of the leading edge of the document D to the stepped portion 3a is detected in advance by setting a predetermined count based on the document passage signal and the document size detection signal of the trailing edge detection sensor 48B.

Based on this document approach signal, a signal is input to the electromagnetic solenoid 35 after the reverse rotation of the conveyor belt 21 is temporarily stopped by the motor reverse rotation stop and the driven rotation of the belt pressing roller 28 is stopped, and the plunger 35A is projected. As a result, the swing lever 34 swings counterclockwise about the rotation center shaft portion 34b, and the swing arm is engaged via the link plate 33 engaged with this.
Since 30 is rocked up about the rocking shaft 31 by rocking clockwise, the recesses 30a of the rocking arm 30 are disengaged from the stepped portion 28 of the belt pressing roller 28, and the belt pressing roller is released. The 28 axis position restrictions are lifted and the robot can move.

The restriction of the belt pressing roller 28 is released while the reverse rotation of the conveyor belt 21 is temporarily stopped by this motor reverse rotation temporary stop, and after a short time, the motor drive relay is actuated again and the reverse rotation of the motor M is restarted. The belt 21 starts reverse running again.

The roller surface 28c of the belt pressing roller 28, which is in sliding contact with the inner surface of the conveyor belt 21 performing the reverse transfer, is movably driven to rotate in the clockwise direction, and the shaft end portion 28a has the bearing member 2
It is guided by each groove 29a of 9 and rolls, and is pulled to the left to approach the vicinity of the left end face of the groove 29a.

When the belt pressing roller 28 is moved to the left, the shaft end 28a of the belt pressing roller 28 separates from each groove 29a of the bearing member 29 and falls into the lower opening 29c, so that the position as shown in FIG. Move to.

FIG. 9B is a partial cross-sectional view of the document feeder showing this state. In the illustrated state, the conveyor belt 21 is pressed from the back surface by the roller surface 28c of the belt pressing roller 28, and the surface side of the conveyor belt 21 is lightly pressed against the step portion 3a of the stopper plate 3 to close the gap g. However, the leading edge of the document conveyed in the reverse direction surely comes into contact with the stepped portion 3a of the stopper plate 3 and stops, and does not enter the sheet feeding unit side. After one end of the document D contacts the stopper plate 3, the motor drive is stopped, the reverse rotation of the conveyor belt 21 is stopped, and the document D is stopped.

The original placed at this accurate stop position is pressed onto the original glass 2 by the conveyor belt 21 under the pressure of the plurality of pressing rollers 27A and 28B, and the exposure of the second side (back side) is started. After that, a known process is performed to form an image and transfer it to a recording sheet to complete one-sided copying. At this time, the image position on the recording paper and the original image position of the document are accurately held.

When the exposure of the back surface of the document D is completed, the transport belt 21 is rotated in the forward direction, and the document D is fed into the paper discharge reversing unit 40 from the feed passage 41, and as described above, the paper discharge roller pair 46,
The anti-transfer entrance 42 through the reversing passages 43, 44 and the reversing roller pair 47
Is conveyed in reverse from the original glass 2. Here, the reverse transfer of the conveyor belt 21 is performed, and during this period, the belt pressing roller 28
Is regulated by solenoid 35. Further, the temporary stop and the release of the regulation of the belt pressing roller 28 just before the end of the reverse transfer line are performed in the same manner as described above.

Thus, the document D is conveyed onto the document glass 2 and has its tip abutted against the step portion 3a of the stopper plate 3 and stopped at a predetermined position.
Is performed in the main body of the copying apparatus in the image forming process after the first surface (front surface) of the original is exposed. When the exposure of the back surface of the document D is completed, the transport belt 21 is rotated in the forward direction, and the document D is pinched by the discharge roller pair 46 from the delivery passage 41.
After passing through the upper surface of the document conveyance switching member 50 in the state where the reversing path is closed, the document D is sent out onto the discharge tray portion 80 through the discharge path 45, and the documents D are sequentially stacked as the copy is repeated.

FIG. 13 (A) is a diagram showing the document feeding path, and the alternate long and short dash line shows the path. According to this transport device, the bundle of documents D is placed on the document receiving tray 13 of the feeding unit 10 with the front surface (second surface) D1A of the first page (D1) of the document lying down. Then, the document D is fed from the last page (for example, D6), the reverse side D6B of the document D6 is copied after reversing, the front surface D6A of the document D6 is copied after reversing, and the document is placed on the discharge tray 80. The surface D6A of D6 is placed face up.

Subsequently, the next original D5 is conveyed and copied, and is placed on the original D6 on the discharge tray 80.

Thus, all originals that have been copied are output to the output tray.
The first page (D1) is loaded on the page 80 with the front surface (D1A) facing upward.

The document feeder of the present invention can also be set to the copy mode for only the first side of the document. FIG. 13 (B) is a diagram showing the document conveying path in this case, and the alternate long and short dash line is the document path. Further, the inside of the circular broken line is a partially enlarged view for explaining the document accumulation state.

The original stack placed on the original receiving tray 13 of the paper feeding unit 10 is placed with the first page as the lowermost layer and the first page (front side) as the lower side.
And then discharged to the discharge tray section 80. At this time, the document D does not pass through the reversing passages 43, 44 and the anti-transfer entrance passage 42, but goes from the sending passage 41 to the discharge roller pair 46 to the discharge passage 45 to the discharge tray portion 80. Further, the belt pressing roller 28 at the entrance of the transport unit 20 has a swing arm formed by the solenoid 35.
The regulating operation of 30 does not operate, and the roller 28 is slidably driven by the forward / reverse rotation of the conveyor belt 21, and can be moved left and right by the forward / reverse rotation and the bearing member 29.

The original D, which is conveyed by sliding rightward on the original glass 2 by the conveyor belt 21, passes through the sensor 18 for detecting the trailing edge of the paper, and then the trailing edge of the original D reaches the stopper plate 3.
After passing through, it slightly overruns and then stops. This is determined by counting up the clock pulse value set according to the length of the detected document size, with the generation of the trailing edge detection signal by the sensor 18 as a base point.

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

When the motor M is started to rotate in the reverse direction, the conveyor belt 21 starts to rotate in the reverse direction to reverse the overrun original D, and after the motor M is rotated by a predetermined pulse in the reverse direction, the rear end of the original D is a stopper plate. The conveyance belt 21 stops running after coming into contact with the stepped portion 3a of No. 3.

When the conveyor belt 21 travels in the reverse direction, the belt pressing roller 28, which is capable of moving the shaft end, is driven to rotate clockwise by the frictional pulling force of the circumscribing conveyor belt 21, while the shaft end portion 28a has a bearing member. Rolling to the left along the groove 29a of 29. And the roller 28c of the belt pressing roller 28
Is located closest to the stepped portion 3a of the stopper 3, and the shaft end portion 28a of the belt pressing roller 28 has a bearing member 29.
It comes into contact with the left end surface of the groove portion 29a, and only driven rotation occurs here. At the left end position, the belt pressing roller 28 comes into light contact with the step portion 3a of the stopper plate 3 via the conveyor belt 21 to close the gap g.

The traveling front end of the document D fed in the reverse direction surely hits the stepped portion 3a of the stopper 3 in this closed state,
The document D is placed at the correct stop position due to the stoppage of the conveyance belt 21. That is, the document D passes through the gap and feed unit 10
Entry to the side is completely prevented.

The original placed at this accurate stop position is pressed onto the original glass 2 by the conveyor belt 21 under the pressure of the plurality of pressing rollers 27A and 27B and the separating roller 38, and the first surface (front surface) is exposed. After the start, a known process is performed to form an image and transfer it to a recording sheet to complete the one-sided copying. At this time, the image position on the recording paper and the original image position of the document are accurately held.

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

The document D enters the discharge path 41 from the right end of the document glass 2 by the conveyance force of the conveyance belt 21, rises, makes a U-turn, and is pressed and pinched at a position above the discharge roller pair 46, and the left discharge path is formed.
The sheet is discharged outward from 45 and placed on the document discharge tray 80 with its first surface facing upward. At this time, the document conveyance switching member 50
Is descending to enter the side of the paper discharge central roller 46A and guides the document D to the paper discharge passage side.

The stacking order of the stack of documents stacked on the document receiving tray 13 and the stacking order of the documents discharged onto the discharge tray unit 80 are the same as those in the double-sided document copying mode described above.

〔The invention's effect〕

As described above, according to the present invention, after the original is drawn onto the original glass by the transport belt that runs forward and backward on the original glass,
In a document feeder configured to reversely convey and bring the document edge into contact with a stopper plate stepped portion provided on the document glass edge,
A belt pressing roller is provided in the vicinity of the step portion of the stopper plate so that the roller can be moved and can be locked by the restricting means. When the original is fed from the paper feeding unit side, a gap for passing the original is formed. When the document is conveyed backward from the paper discharge unit side and the trailing edge of the document comes close to the stopper plate, the gap is closed. Can be done accurately and reliably.

Further, the bell pressing roller according to the present invention is supported independently of the driving roller like the conventional apparatus and operates independently with the timing adjusted, so that the bell pressing roller does not depend on the relative condition between the driving roller shaft and the stopper plate step portion, and the positioning is performed. Has various excellent effects such as accurate adjustment.

[Brief description of drawings]

FIG. 1 is an external perspective view of a copying machine equipped with a document feeder according to the present invention. FIG. 2 is a cross-sectional view of the document feeding device showing the document feeding path. FIG. 3 is a perspective view showing a drive system of the document feeder. 4, 5, 6, and 7 are a cross-sectional view, a plan view, a perspective view and an exploded perspective view showing a main part near the drive roller of the document feeder. 8A and 8B are enlarged sectional views showing details of the shaft end portion of the belt pressing roller. 9 (A) and 9 (B) are partial cross-sectional views for explaining the regulation / release state of the belt pressing roller. 10 and 11 are a flowchart and a timing chart for explaining the document conveying process, and FIG. 12 is a block diagram showing the control of the document conveying device. FIGS. 13 (A) and 13 (B) are diagrams showing the conveyance paths for double-sided originals and single-sided originals. 1 ... Copying device main body, 2 ... Original glass 3 ... Stopper plate, 3a ... Step section 5 ... Original document feeder, 10 ... Paper feeding unit 20 ... Transport unit, 21 ... Transport belt 23 ... Drive rollers 27A, 27B …… Pressing roller 28 …… Belt pressing roller 28a …… Shaft end, 28c …… Roller surface 29A, 29B …… Bearing member, 29a …… Groove 29b …… Shaft support, 29c …… Opening 30A, 30B …… swing arm, 30a …… recess 31 …… swing shaft, 32A, 32B …… hinge shaft 33 …… link plate, 34 …… swing lever 35 …… electromagnetic solenoid, 36 …… holding plate 38: Separation roller 40: Paper ejection reversing unit 46: Paper ejection roller pair, 47: Reversal roller pair 48A: Front edge detection sensor (paper ejection sensor) 48B: Rear edge detection sensor (reversal paper sensor) ) 50 ... Original transport switching member, 80 ... Ejection tray section D, D1, D2, D3, D4, D5, D6.

Claims (1)

(57) [Claims] 1. A document is drawn onto a document glass by a conveyor belt which runs on the document glass in a normal and reverse direction, and is then conveyed in the opposite direction so that the document edge is brought into contact with a stopper plate step portion provided on the document glass edge. In the original conveying apparatus configured as described above, in the vicinity of the stopper plate step portion, a belt pressing roller that moves in response to forward and reverse running of the conveyance belt, and the belt pressing roller at a predetermined position apart from the stopper plate step portion. When a document is conveyed near the stopper plate step portion during reverse rotation of the conveyor belt, the regulating means is operated to operate the regulating means. The member releases the engagement with the belt pressing roller for pressing the belt, and the belt pressing roller moves in the direction of the stopper plate step by the frictional force of the conveyor belt traveling in the reverse direction. Moving to, document feeder being characterized in that so as to contact the original on the original glass stopper plate stepped portion.