JP3366984B2 - Automatic document feeder - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic document feeder installed in a document processor such as an electrostatic copying machine, and more particularly to an automatic document feeder equipped with a vacuum type document separating / feeding means.

[0002]

2. Description of the Related Art In recent years, a copying machine has come to use an automatic document feeder for automatically feeding a plurality of documents to a document setting position on the upper surface of a transparent plate in accordance with the speeding up and automation of the copying process. There is. This kind of automatic document feeder has
A document separating / feeding mechanism is provided for separating and feeding the lowest one of a plurality of documents placed on a document table. This type of document separating / feeding mechanism includes a plurality of documents which are arranged below a guide plate arranged in front of the document table in the conveying direction and which are projected upward through an opening formed in the guide plate. What is generally used is composed of a feeding roller having a roller and a separating belt mechanism which is arranged above the feeding roller so as to face the feeding roller. However, since such a document separating / feeding mechanism is configured such that a large frictional force acts between the lowest document and the second document from the bottom, the lowest document is In the case of writing with a writing instrument such as a pencil, which tends to fall off by frictional contact, there is a problem that the back surface of the second document from the bottom is stained by the lowest document.

As a document separating / feeding mechanism for solving the above problems, a document table having an opening at the front portion in the document conveying direction,
A vacuum chamber whose upper surface is disposed below the opening of the original table substantially flush with the upper surface of the original table and which has an opening on the upper surface, and which is arranged by winding the vacuum chamber to operate in the original conveying direction. And a vacuum separating and feeding means having a separating air ejecting means for ejecting air toward a front end of a document placed on the document table. A document separating / feeding mechanism of an automatic document feeder, in which the lowest document among the documents placed on a sheet is attracted to a feeding belt and is fed, is disclosed in, for example, Japanese Patent Laid-Open No. 56-56443. It is disclosed in Japanese Unexamined Patent Publication No. Sho 62-93141.

[0004]

In the document separating / feeding mechanism, when air is jetted by the separating air jetting means 62 to the front end of the document placed on the document table, the space between the documents is increased. Air is blown into the originals, and the originals above the second lowest one are lifted and separated at the front end of the originals, but the air is not blown from the central part to the rear end of the originals. Are in contact with each other. Therefore, when the lowermost original is attracted to the feeding belt of the vacuum separating and feeding means and fed, the uppermost second uppermost original is also dragged by the frictional force due to the contact and is fed out. So-called double feeding occurs. However, in order to prevent double feeding of the uppermost second document when feeding the document, the document separating member should be provided at the front end of the document table at a slight distance from the upper surface of the document table. However, providing the document separating member increases the number of parts and increases the cost, and there is a problem in space for disposing the document separating member.

The present invention has been made in view of the above facts, and its main technical problem is that the set original stopper for positioning the front end of the original placed on the original table also functions as an original separating member. An object of the present invention is to provide an inexpensive automatic document feeder having a double feed prevention function.

[0006]

According to the present invention, in order to achieve the above-mentioned technical objects, a document table having an opening at a front portion in the document conveying direction, and an upper surface below the opening of the document table. Is a vacuum chamber which is disposed substantially flush with the upper surface of the original table and has an opening in the upper surface, and a feeding belt which is provided with a plurality of holes wound around the vacuum chamber and operated in the original conveying direction. A vacuum separating / feeding means having a separating air ejecting means for ejecting air toward the front end of the original placed on the original table; and a set for positioning the front end of the original placed on the original table. In an automatic document feeder including a document stopper and a stopper actuating unit that operates the set document stopper, the set document stopper includes an actuated portion formed by bending at an upper end portion. Between the stop position where the lower end of the original table is in contact with the upper surface of the original table and the lower end of the original table is separated from the upper surface of the original table by a predetermined distance. The stopper actuating means comprises an actuating shaft equipped with an actuating cam that abuts the lower surface of the operated portion of the set document stopper, and a driving means for rotating the actuating shaft. An automatic document feeder, wherein the set document stopper is selectively positioned at the stop position and the document separating position by rotating the operation shaft by a predetermined angle by the driving means. An automatic document feeder is provided.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of an automatic document feeder constructed according to the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows an upper end portion of an electrostatic copying machine 2 and an automatic document feeder 4 mounted on the upper end portion. The electrostatic copying machine 2 has a housing 6, and a transparent plate 8 which may be a glass plate is arranged on the upper surface of the housing 6. On one side (the left side in FIG. 1) of the transparent plate 8, a document regulating member 10 that determines a document setting reference position is arranged.
An automatic document feeder 4 constructed in accordance with the present invention is mounted on the upper surface of a housing 6 of an electrostatic copying machine 2 so as to be rotatable about a rotation axis extending along a rear side edge of a transparent plate 8. . When a document is manually placed on the transparent plate 8 of the electrostatic copying machine 2, the automatic document feeder 4 is swung upward from the closed position shown in the drawing to the open position to expose the transparent plate 8. A document is placed at a desired position on the transparent plate 8, and the automatic document feeder 4 is set to the closed position shown to cover the transparent plate 8 and the document placed on the transparent plate 8. When a document is placed on the transparent plate 8, one edge of the document is brought into contact with the leading edge of the document regulating member 10 and the one edge of the document is positioned at the document setting reference position so that the document is placed at a desired position. Can be positioned at. Transparent plate 8 using automatic document feeder 4
When the original is automatically loaded onto the transparent plate 8 and automatically loaded from the transparent plate 8, the automatic document feeder 4 is used in the closed position.

Continuing the description with reference to FIGS. 1 and 2, the illustrated automatic document feeder 4 includes side plates 11 arranged at intervals in the front-rear direction (direction perpendicular to the paper surface in FIG. 1). An original table 12 is provided as an original placing means disposed between (only the back side plate is shown by a two-dot chain line in FIG. 1). The document table 12 is provided with a large first opening 14 at the front side (the left side in FIGS. 1 and 2) in the document transport direction on the back side (upper side in FIG. 2), and the first opening 14 is provided. A second opening 16 smaller than the first opening 14 is formed on the front side (on the left side in FIG. 2) in the document conveying direction on the front side of the opening 14. Further, the document table 12 has a pair of guide grooves 18, 18 extending in the width direction behind the second opening 16 in the document transport direction.
Is provided. Support leg portions of a width regulating member 20 for regulating the widthwise position of the document placed on the document table 12 are fitted into the pair of guide grooves 18, 18. The width regulating member 20 is configured to be movable in the vertical direction in FIG. 2 along the pair of guide grooves 18, 18. In the automatic document feeder 4 in the illustrated embodiment, the position reference of the document placed on the document table 12 is the back side (one side) reference, and the document is placed upright on the back side of the document table 12. The widthwise position of the document placed on the document table 12 is regulated by the inner surface of the side plate 22 and the inner surface of the width regulating member 20. A sensor hole 17 is provided on the back side of the front end of the document table 12 in the document transport direction, and a reflective first document detection sensor 21 is provided below the sensor hole 17. .
The first document detection sensor 21 detects a document placed on the document table 12 and sends a detection signal to a control unit (not shown). In addition, the second
A sensor hole 18 is provided at a position corresponding to the front side (lower side in FIG. 2) of the opening 16 of the above, and a reflective second original detection sensor 23 is provided below the sensor hole 18. There is. The second original detection sensor 23 detects the original placed on the original table 12 when the original size of the original placed on the original table 12 is larger than the second opening 16 from the inner surface of the side plate 22. Functions as a document detecting unit that detects whether or not the document is located on the second opening 16 and sends the detection signal to a control unit (not shown). The document detecting means for detecting whether or not the document placed on the document table 12 is positioned on the second opening 16 is a device for detecting the document size by the moving position of the width regulating member 20. The detection signal may be used.

A vacuum separating / feeding means 24 is arranged below the original table 12 in correspondence with the first opening 14. This vacuum separating and feeding means 24 is
Vacuum chamber 26 and the vacuum chamber 26
Of the driving roller 28 and the driven roller 30, which are arranged in parallel to each other on the front side and the rear side of the original conveying direction, the driving roller 28, the driven roller 30, and the vacuum chamber 26.
Is provided and is provided with four feeding belts 32. The vacuum chamber 26 is made of a synthetic resin, and has four openings 261 on the front side in the original conveying direction and four openings 262 on the rear side in the original conveying direction of the four openings 261 on the upper wall. ing. The vacuum chamber 26 thus configured is attached to the lower surface of the original table 12 by an appropriate supporting means (not shown) so that the upper surface thereof is substantially flush with the upper surface of the original table 12. The vacuum chamber 26 is connected to a suction blower 36 via a duct 34 connected to a hole (not shown) formed in a wall on the back side thereof. The drive roller 28 is provided so as to penetrate through support walls 263 and 264 provided so as to project from both side walls of the vacuum chamber 26 to the front side in the document transport direction, and both ends thereof project downward from the lower surface of the document table 12. Provided support wall 12
A rotary shaft 281 rotatably supported by bearings 37 and 38 on the bearings 1 and 122, the above four openings 261 on the rotary shaft 281, and four rollers 282 arranged corresponding to the document conveying direction. It consists of A roller drive gear 39 is attached to one end of the rotary shaft 281 of the drive roller 28 thus configured, and the roller drive gear 39 is transmission-coupled to a drive mechanism (not shown) and is rotationally driven in a direction indicated by an arrow. . The driven roller 30 includes a shaft 301 supported by support walls 265 and 266 provided on both side walls of the vacuum chamber 26 so as to project rearward in the document transport direction, and the shaft 3
01 includes the above-mentioned four openings 262 and four rollers 302 which are rotatably arranged in correspondence with the document conveying direction. The four feeding belts 32 have a plurality of holes 3
21 and is wound around each of the rollers 282 and 302 corresponding to the original conveying direction of the driving roller 28 and the driven roller 30. The feeding belt 32 configured as described above is arranged so that its upper surface is located slightly above the upper surface of the document table 12.

Below the original table 12, as shown in FIG. 2, the feeding drum 4 is provided corresponding to the second opening 16.
0 is set. As shown in FIGS. 3 and 4, the feeding drum 40 is made of synthetic resin and is provided with a plurality of holes 401 around it. One end of the feeding drum 40 is open, and the duct 42 connected to the vacuum chamber 26 is inserted from the opened one end. The duct 42 includes a suction section 421 and a connection section 422. The suction part 421 has an opening 4 as shown in FIG.
Equipped with 23. The opening 423 is formed such that only the upper side of the suction portion 421 is opened in the axial direction. This opening 42
The upper end sides of the side walls 424 and 425 of the duct 42 forming No. 3 are formed as close to the inner peripheral surface of the feeding drum 40 as possible. Therefore, each of the plurality of holes 401 formed in the feeding drum 40 faces the opening 423 of the duct 42 and communicates with the duct 42 only when positioned above. A bearing 44 is disposed between one end of the connecting portion 422 forming the duct 42 on the suction portion 421 side and one end of the feeding drum 40, and the feeding drum 40 is rotatably supported by the duct 42. ing. Between the duct 42 and the vacuum chamber 26, an opening / closing valve 46 that constitutes an opening / closing means that connects or disconnects the vacuum chamber 26 and the feeding drum 40 is provided. The open / close valve 46 includes a valve housing 461 and a butterfly valve 463 mounted on a valve shaft 462 mounted on the valve housing 461. One end of the valve housing 461 is inserted and connected into the vacuum chamber 26 through a connection hole 267 formed in the side wall of the vacuum chamber 26. A flange 464 is provided on the outer circumference of one end of the valve housing 461, and the insertion into the vacuum chamber 26 is restricted. The flange 464 is used for the vacuum chamber 26.
It is fixed to the side wall of the device by fixing means such as screws. The other end of the valve housing 461 is inserted and connected to the other end of the connecting portion 422 that forms the duct 42. A flange 465 is also provided on the outer circumference of the other end of the valve housing 461 to restrict the insertion into the duct 42. A lever 466 is mounted on the valve shaft 462 of the on-off valve 46 thus configured, and the lever 466 is connected to the plunger of the solenoid 468 (see FIG. 1) via a link mechanism. The butterfly valve 463, which is operated by the solenoid 468, is in a closed state when the solenoid 468 is deenergized and opens when the solenoid 468 is energized. The solenoid 46
8 is deenergized when the second original detection sensor 23 does not detect an original, and is activated by a control means (not shown) when the second original detection sensor 23 detects the detection of an original. Has become.

An end wall 402 is provided at the other end of the feeding drum 40.
Is provided. At the center of this end wall 402 is a boss 4.
03 is formed, and the shaft fitting hole 404 is formed in the boss 403.
And a pin fitting groove 405 are provided. Feeding drum 40
One end portion of the rotary shaft 48 is fitted into the shaft fitting hole 404 provided in the boss 403 of the end wall 402 constituting the. A pin insertion hole 481 is formed in the rotary shaft 48 so as to pass through the shaft core in a radial direction, and a pin 50 fitted in the pin insertion hole 481 is formed in the pin fitting groove formed in the boss 403. The drive force of the rotary shaft 48 is transmitted to the feeding drum 40 by being fitted with 405. A bearing 52 is arranged between one end of the rotary shaft 48 inserted into the feeding drum 40 and one end of the suction portion 421 forming the duct 42, and the other end of the duct 42 is provided at the rotary shaft 48. Is rotatably supported at one end thereof. This rotating shaft 48
Has an intermediate portion rotatably supported by a support wall 123 provided so as to project downward from the lower surface of the original table 12 via a bearing 54, and has the other end rotatably supported by the support wall 121 by a bearing 58. Is supported by. Rotating shaft 4
A feed drum drive gear 59 is loosely fitted to the other end portion of 8, and an electromagnetic clutch 56 for transmitting and coupling the feed drum drive gear 59 to the rotary shaft 48 is provided. Therefore, when the electromagnetic clutch 56 is deenergized, the rotating shaft 48 and the feed drum drive gear 59 can rotate relative to each other, and when the electromagnetic clutch 56 is energized, the rotating shaft 4 can rotate.
8 and the feed drum drive gear 59 are transmission-coupled. The feeding drum drive gear 59 is an intermediate gear 6 as shown in FIG.
It is transmission-coupled to the roller drive gear 39 via 1. The roller drive gear 39 to the feeding drum 40
The number of teeth of the intermediate gear 61 as the drive means for transmitting power to the drive shaft 60 of the drive shaft 60 and the number of teeth of the feed drum drive gear 59 are the moving speed of the feed belt 32 operated by the drive roller 28 of the vacuum separation feed means 24. And feeding drum 40
Is set to be substantially the same as the peripheral speed of. The electromagnetic clutch 56 is deenergized when the second document detection sensor 23 does not detect a document, and
When the document detection sensor 23 detects the detection of the document, it is energized by a control means (not shown).

The vacuum separating / feeding means 24 is provided with a separating air jetting means 62 called an air knife which is arranged above the front end of the original table 12 in the original conveying direction. The separated air ejecting means 62 supplies air to the air chamber 621, a nozzle 622 that ejects the air in the air chamber 621 toward the front end portion of the document set on the document table 12, and the air chamber 621. It has a blower 623 and a servomotor 624 for driving the blower 623.
In the illustrated embodiment, the servo motor 624 has its rotation speed adjusted by a control unit (not shown) based on a detection signal from a document stack amount detection unit, which will be described later, that is, the stack amount of the set document placed on the document table 12. It is supposed to be done. That is, the rotation speed of the servo motor 624 is high when the stacking amount of the set document is large, and the rotation speed of the servo motor 624 is small when the stacking amount of the set document is small. Therefore, the blower 623 driven by the servomotor 624 has its rotation speed adjusted in accordance with the stacking amount of the originals, that is, the weight of the originals set on the original table 12, and thus the air ejection amount ejected from the nozzle 622. Is adjusted according to the weight of the original on the original table 12. When the air is ejected from the nozzle 622 of the separation air ejecting means 62 configured as described above, the air is blown between the respective originals placed on the original table 12 to perform a so-called separation action for separating the respective originals. Be seen.

A set original document stopper 63 is provided above the front end of the vacuum separating / feeding means 24 in the original document conveying direction, and a discharge original document stopper 64 is provided upstream of the set original document stopper 63 in the original document conveying direction. In the illustrated embodiment, the set original document stopper 63 and the discharged original document stopper 64 are spaced from each other in the width direction of the original table 12 (the direction perpendicular to the paper surface in FIGS. 1, 5 and 6, and the horizontal direction in FIG. 7). There are three of each. These set original document stopper 63 and ejected original document stopper 64
Are movably supported in the vertical direction by support means 66 and 67 attached to the upper wall 65 made of synthetic resin attached to the upper ends of the side plates 11.

The set original document stopper 63 is made of a metal plate such as stainless steel, an elongated hole 631 is provided in an intermediate portion thereof, and an upper end portion thereof is bent to form an actuated portion 632. On the other hand, the supporting means 66 for supporting the set original document stopper 63 is composed of a mounting boss 661 integrally formed on the upper wall 65 made of the synthetic resin so as to project downward, and a metal plate mounted on the boss 661 with screws 662. The support plate 663 is provided. This support plate 663 has a hole 66 at its center.
4 is provided, and guide portions 665, 665 whose both sides are bent at substantially right angles are formed at the lower end portion thereof.
The set original document stopper 63 is supported by the support plate 663 configured as described above so as to be vertically movable.
That is, the set document stopper 63 is disposed between the guide portions 665 and 665 of the support plate 663, and the support plate 663 is provided.
The bolt 666 is inserted into the hole 664 provided in the slot and the elongated hole 631 provided in the set document stopper 63, and the nut 667 is screwed into the bolt 666. The set document stopper 63 thus supported by the supporting means 66 has a stop position (see FIG. 5) at which the lower end abuts the upper surface of the document table 12 and a lower end of the set document stopper 63 above the upper surface of the document table 12 by a predetermined distance. It is configured to be movable between a document separating position (see FIG. 1 and FIG. 6) with a cover. The distance between the upper surface of the document table 12 and the lower end of the set document stopper 63 is preferably set to 2.0 to 3.0 mm with the set document stopper 63 positioned at the document separating position. When air is jetted by the separation air jetting means 62 to the front end of the original placed on the original table 12 as described above, air is blown between the originals, and two sheets from the bottom of the original are placed at the front end of the original. The originals above the eyes are lifted and separated, but since the air is not blown from the central portion to the rear end of the originals, the originals are in contact with each other. Therefore, when the lowest document is attracted to the feeding belt 32 of the vacuum separating and feeding means 24 and fed,
The so-called double feeding is also caused in which the documents above the second sheet from the bottom are dragged by the frictional force due to the contact and fed out. At this time, if the distance between the upper surface of the document table 12 and the lower end of the set document stopper 63 is set to 2.0 to 3.0 mm, the lowest document adsorbed on the feeding belt 32 is the set document stopper. 63 is smoothly fed without interfering with 63, and the front end portion of the second and upper originals is lifted by the separated air, so that the original comes into contact with the set original stopper 63 and its movement is restricted. ,
Double feeding of documents is prevented. As described above, the set original document stopper 63 also has a function of preventing double feeding of originals.

The ejected document stopper 64 is made of synthetic resin in the illustrated embodiment and has an elongated hole 64 in the middle thereof, and actuated projections 642 and 642 on both sides of the upper end thereof. Is equipped with. On the other hand, as shown in FIG. 8, the supporting means 67 for supporting the ejected document stopper 64 is provided with a supporting member 671 which is integrally formed so as to project downward from the upper wall 65 made of the synthetic resin, and a guide member 67.
3 and 673. The support member 671 is provided with a guide protrusion 672 at the center of its lower end. The guide members 673 and 673 are respectively arranged at a predetermined distance (a distance slightly larger than the thickness of the discharged document stopper 64) from the support member 671 and at positions facing both side portions of the support member 671. . The support member 671 and the guide members 673 and 673 of the support means 67 configured as described above.
The ejected document stopper 64 is inserted between the ejected document stopper 64 and the supporting member 671 in the long hole 641 provided in the ejected document stopper 64.
The ejected document stopper 64 is supported by the support means 67 so as to be vertically movable by fitting the guide protrusion 672 provided on the. The ejected document stopper 64 supported by the support means 67 in this manner is in a regulation position where it comes into contact with the set document placed on the document table 12 (see FIGS. 1 and 6).
And a retracted position for retracting above the document table 12 (see FIG.
(See) and is configured to be movable between. The ejected document stopper 64 is positioned at a regulation position where it comes into contact with a set document placed on the document table 12,
When the set originals are fed and the set originals on the original table 12 decrease, the operation of the elongated holes 641 causes the originals to drop by its own weight following the decrease of the originals. Therefore, the discharged document stopper 64 also functions as a means for preventing the set document from floating. Further, since the three discharged document stoppers 64 are independently supported by the respective three supporting means 67, even when the set document is lifted, the respective discharged document stoppers 64 are always in contact with the lifted document. Therefore, it is possible to prevent the discharged document from slipping under the discharged document stopper 64.

Next, the stopper operating means 68 for positioning the set original document stopper 63 and the discharged original document stopper 64 at predetermined positions will be described with reference to FIG.
The stopper operating means 68 is an operating mechanism 680 and one solenoid 6 as a driving means for driving the operating mechanism 680.
84 are provided. The operating mechanism 680 that constitutes the stopper operating means 68 is provided downstream of the set original stopper 63 in the original conveying direction, and includes an operating shaft 681 that is rotatably supported by both side plates 11. This operating shaft 681
3 at the position corresponding to the set original document stopper 63.
A plurality of operating cams 682 are mounted, and three operating levers 683 are mounted at positions corresponding to the discharged document stopper 64. The three actuating cams 682 are arranged in contact with the lower surfaces of the actuated portions 632 of the three set original document stoppers 63, and are rotated by the rotation of the operating shaft 681 to move the set original document stoppers 63 to the stop position. And move to the document separation position. 3 actuating levers 683
Is composed of a metal plate such as stainless steel,
Two actuating pieces 683a, 683a are respectively formed at one end thereof so as to project, and the other end is provided with a screw 68 on the actuating shaft 681.
It is attached by 3b and 683b. Two operating pieces 683a, 683a provided on the operating lever 683
Has a space slightly larger than the width of the discharge original stopper 64, and positions the discharge original stopper 64 between both operating pieces to engage with the actuated projections 642 and 642 provided on the discharge original stopper 64. It is like this. Therefore, the operating lever 683 is rotated by the rotation of the operating shaft 681 to move the discharged document stopper 64 to the regulating position and the retracted position. One solenoid 684 as a driving unit that constitutes the stopper actuating unit 68 is
The plunger 684a is connected by a pin 686 to a lever 685 attached to the end portion of the operating shaft 681 on the inner side to rotate the operating shaft 681 by a predetermined angle. A lever 685 mounted on the operating shaft 681 has a return spring 687 whose one end is locked to a fixed portion such as a side plate.
The other end of the return spring 68 is locked.
By the action of 7, the operating shaft 681 is moved to the arrow 681 in FIG.
It is urged to rotate in the direction indicated by A. Therefore, the operating shaft 681, the operating cam 682 mounted on the operating shaft 681, and the operating lever 683 are positioned in the state of FIG. 5 when the solenoid 684 is deenergized. That is, the base circle of the operating cam 682 abuts the lower surface of the operated portion 632 of the set original stopper 63, the set original stopper 63 is positioned at the stop position, and the operating lever 683 rotates upward to eject the original stopper 64. Is located at the retracted position. When the solenoid 684 is urged from the state of FIG. 5, the actuating shaft 681 is rotated in the direction indicated by the arrow 681B in FIG. 9 via the plunger 684a and the lever 685, so that the actuating shaft 681 mounted on the actuating shaft 681 is actuated. The cam 682 and the operating lever 683 are positioned in the states shown in FIGS. 1 and 6. That is, the set original stopper 63 is positioned at the original separating position by the cam portion of the operating cam 682, the operating lever 683 rotates downward, and the discharged original stopper 64 is positioned at the regulating position. Since the stopper operating means 68 for operating the set original document stopper and the ejected original document stopper is composed of one solenoid 684 and the operating mechanism 680, it can be manufactured at low cost, and the operating mechanism 680 is Since the operation shaft 681 is combined with the operation cam 682 and the operation lever 683, the structure is compact and the document table 12 can be easily placed above.

The illustrated automatic document feeder 4 is provided with a document stacking amount detecting means 69 for detecting the stacking amount of the set documents placed on the document table 12. The document stacking amount detecting means 69 includes a detecting member 691 and two detectors 692, 69.
2 and. The detection member 691 is made of a synthetic resin, and the detection unit 691 is formed on the front side of the document table 12 and is placed on the set original document on the original document table 12 at an intermediate portion thereof.
A is provided, and at one end thereof, a shield portion 691b that is formed so as to project to the back side and shields the light of the detector 692 is provided. In addition, an actuated projection 691c is provided in the middle of the detection member 691 so as to project inward and engage with an actuating lever described later. The detection member 691 configured as described above is rotatably supported at the other end by a short shaft 693 fixed to a side plate on the back side. In the illustrated embodiment, the detecting portion 691a of the detecting member 691 is configured to be positioned between the set original document stopper 63 and the ejected original document stopper 64 in a state of being placed on the set original document. There is. Therefore, the document returned onto the set document after the set document is fed does not come into contact with the detection portion 691a of the detection member 691. 2 above
Each of the detectors 692 and 692 includes a light emitting element 692a and a light receiving element 692b, as shown in FIGS.
And are arranged above and below and are attached to, for example, the side plate on the back side. By these two detectors 692 and 692 and the shielding portion 691b of the detecting member 691 which moves between the two elements, the height position of the detecting portion 691a, that is, the stacking amount of the set original can be detected in four steps. That is, the detectors 692 and 6 having a large stacking amount of set originals and two shields 691b
A first state located above 92, a second state in which the shield portion 691b shields only the upper detector 692, and a third state in which the shield portion 691b shields the two detectors 692 and 692. Then, the fourth state in which the shielding unit 691b shields only the lower detector 692 can be detected. Also,
The stopper operating means 68 is an original stacking amount detecting means 69.
The operating lever 694 that engages with the actuated projection 691c of the detecting member 691 and that moves the detecting portion 691a of the detecting member 691 to the detecting position and the retracted position is provided.
The actuating lever 694 is mounted on the actuating shaft 681 of the stopper actuating means 68, and the tip end portion thereof is engaged with the actuated projection 691c of the detecting member 691. That is, when the solenoid 684 is deenergized, the actuating lever 694 rotates the detection member 691 upward to the retracted position as shown in FIG. 5, and the electromagnetic solenoid 684 is energized from the state of FIG. Then, the operating lever 694
Is rotated downward, the detection member 691 is rotated downward by its own weight, and the detection portion 691a is positioned at the detection position where it abuts against the set original.

Continuing the description with reference to FIG. 1, a pair of paper feed rollers 70 is provided downstream of the original table 12 in the original conveying direction.
Is provided. The paper feed roller pair 70 includes a drive roller 701 and a driven roller 702, and the drive roller 701 is rotationally driven in the direction indicated by an arrow by a drive mechanism (not shown). On the downstream side of the paper feed roller pair 70, an original carry-in path 72 for guiding the original fed by the paper feed roller pair 70 onto the transparent plate 8 is provided. A pair of registration rollers 74 is arranged in the original carry-in path 72. The registration roller pair 74 includes a driving roller 741 and a driven roller 742, and the driving roller 741 is rotationally driven in a direction indicated by an arrow by a driving mechanism (not shown).

A conveyor belt mechanism 7 is provided above the transparent plate 8.
6 are provided. The transport belt mechanism 76, which constitutes the document transport means, includes a drive roller 761 and a driven roller 762, which are arranged at intervals in the transport direction of the transparent plate 8, and an endless belt wound around the drive roller 761 and the driven roller 762. Belt 763, driving roller 761 and driven roller 7
62 and rolling rollers 764a, 764
b, 764c, 764d, 764e. The lower running portion of the endless belt 763 extends along the transparent plate 8 of the electrostatic copying machine 2, and a document transport path 78 is defined between the two. In the transport belt mechanism 76 thus configured, the drive roller 761 is rotationally driven by a drive mechanism (not shown).

On the right side of the document transport path 78 in FIG. 1, a document unloading path 80 is provided. In the document carry-out path 80, conveying roller pairs 82 and 84 and a discharge roller pair 86 are arranged. The transport roller pairs 82 and 84 are composed of drive rollers 821 and 841 and driven rollers 822 and 842, respectively, and the discharge roller pair 86 is also the drive roller 8.
61 and a driven roller 862, and these driving rollers 821, 841, and 861 are rotationally driven in the direction indicated by the arrow by a driving mechanism (not shown). Below the discharge roller pair 86, an extruding plate 88 is arranged which is movable in the left-right direction in FIG. 1 by a predetermined amount. The push-out plate 88 has a pair of discharge rollers 8.
6 has a function of supporting the rear end of the document discharged by 6 and stopped by the discharged document stopper 66, and pushing the discharged document to the left in FIG. 1 to move it to the set document stopper 64. . Therefore, the moving amount of the pushing plate 88 is set to the distance between the set original document stopper 64 and the discharged original document stopper 66.
The pair of discharge rollers 86 and the push-out plate 88 constitute a discharge unit, which is movable in the left-right direction in FIG. 1 according to the size of the document placed on the document table 12. The discharge roller pair 86 and the pushing plate 88
The moving mechanism of the discharge unit and the moving mechanism of the pushing plate 88, which are configured by
The technique disclosed in Japanese Patent Publication No. 7 can be used. Since the moving mechanism of the discharging unit and the moving mechanism of the pushing plate 88 are not directly related to the present invention, detailed description thereof will be omitted.

The automatic document feeder according to the illustrated embodiment is constructed as described above, and its operation will be described below. First, the case of using a document having a small width dimension such as A4 or B5 size will be described. When setting a document on the document table 12, the electromagnetic solenoid 684 of the stopper operating means 68 is deenergized. Therefore, the set original document stopper 63 and the ejected original document stopper 6
4 is the state shown in FIG. 5, that is, the set original document stopper 63 is positioned at the stop position, and the discharged original document stopper 64 is shown.
Is located at the retracted position. Further, the detection member 691 of the document stack amount detection means 69 is also positioned at the retracted position. In this state, the original is brought into contact with the set original stopper 63 whose front end is in the stop position and placed on the original table 12, and the width regulating member 20 is moved upward in FIG. 2 to regulate the inner surface of the side plate 22 and the width. The position of the document in the width direction is regulated by the inner surface of the member 20. When a document having a small width dimension is set on the document table 12 as described above, the position of the front edge of the document, that is, the lower edge in FIG. 2, does not reach the second opening 16. . In this way, when a document is set on the document table 12, the first document detection sensor 21 detects that the document is set on the document table 12, and the detection signal is sent to the control means (not shown). Sent. When a copy start switch (not shown) is turned on in this state, the solenoid 684 of the stopper operating means 68 is energized to set the set document stopper 63.
1 and 5, that is, the set document stopper 63 is positioned at the document separating position, and the discharge document stopper 64 is positioned at the regulating position. Further, the detection member 691 of the document stacking amount detection means 69 is positioned at the detection position. Then, the pushing plate 88 is moved from the position indicated by the solid line to the position indicated by the chain double-dashed line by a moving mechanism (not shown), the copying operation is started, the suction blower 36 is driven, and the air in the vacuum chamber 26 is sucked. To be done. Therefore, the lowest document among the documents placed on the document table 12 is attracted to the feeding belt 32 of the vacuum separating and feeding means 24. At this time, the electric motor 624 of the separation air ejecting means 62 is driven to operate the blower 623, and air is ejected from the nozzle 622 toward the front end of the document placed on the document table 20. Air is blown between the placed originals so that the originals are separated and the front end of the originals above the second sheet is lifted above the lower end of the set original stopper 63. The movement to the downstream side is restricted, and the double feeding of documents is prevented. On the other hand, when the copy start switch is turned on, the drive roller 28 is rotationally driven by the drive mechanism (not shown) via the roller drive gear 39 in the direction indicated by the arrow. When the drive roller 28 rotates, the feeding belt 32 is actuated in the direction indicated by the arrow, and thus the lowest document adsorbed on the feeding belt 32 as described above is fed to the downstream side in the conveying direction. . When the original having a small width is used, the second original detecting sensor 23 does not detect the original, and therefore the solenoid 468 is deenergized, so that the open / close valve 46 is closed and the vacuum chamber is closed. The communication between 26 and the feeding drum 40 is cut off. If the second document detection sensor 23 does not detect a document, the electromagnetic clutch 56 is also deenergized, so that the feeding drum 40 is also stopped.

As described above, the document fed by the vacuum separating and feeding means 24 is conveyed to the document carry-in path 72 by the paper feed roller pair 70, and the front end of the registration roller pair 74 in the inoperative state. The sheet is brought into contact with the nip portion, and the primary sheet feeding is completed. Next, the document which is fed to the nip portion by the operation of the registration roller pair 74 is transported toward a document transport path 78 extending along the transparent plate 8 of the electrostatic copying machine 2, and further, The transparent belt 8 is transported from the left side to the right side in FIG.
The sheet is positioned at a predetermined position and the secondary sheet feeding is completed. The exposure operation is executed in this state.

As described above, when the original is exposed on the transparent plate 8 and the exposure operation of the original is completed, the conveyor belt mechanism 76 is operated to convey the original on the transparent plate 8 toward the original discharge path 80. . The document conveyed to the document discharge path 80 is conveyed toward the discharge roller pair 86 by the conveyance roller pairs 82 and 84, and the document table 1 is conveyed from the discharge roller pair 86.
It is carried out on the set original placed on 2. At this time, the front end of the discharged original is brought into contact with the discharged original stopper 64 to be distinguished from the original set first. Also,
The rear end of the document discharged onto the document table 12 is shown in FIG.
Is supported on the push-out plate 88 positioned at the position indicated by the chain double-dashed line. In this way, if all the set originals placed on the original table 12 are fed and returned to the original table 12 after the exposure operation, the electromagnetic solenoid 684 of the stopper actuating means 68 is deenergized. The original document stopper 63, the discharged original document stopper 64, and the detection member 691 of the original document stacking amount detection means 69 are in the state shown in FIG. 5, that is, the set original document stopper 63 is positioned at the stop position and the discharged original document stopper 64 is positioned at the retracted position. At the same time, the detection member 691 of the document stack amount detection means 69 is positioned at the retracted position. On the other hand, the pushing plate 88 is moved from the position shown by the chain double-dashed line in FIG. 1 to the position shown by the solid line by a moving mechanism (not shown). By the movement of the push-out plate 88 to the position shown by the solid line, the rear end portion of the document discharged onto the document table 12 and supported by the push-out plate 88 is dropped onto the document table 12. When the document discharged onto the document table 12 is copied again, the pushing plate 88 is moved to the position shown by the chain double-dashed line in FIG.
The original returned to No. 2 is pushed to the left in the figure by the push-out plate 88, its front end is brought into contact with the set original stopper 63, and is set again.

Next, a case of using a document having a large widthwise dimension such as A3 or B4 size will be described. When setting the original on the original table 12, the electromagnetic solenoid 684 of the stopper operating means 68 is deenergized, and the set original stopper 63, the discharged original stopper 64, and the detection member 691 of the original stack amount detecting means 69 are shown in FIG. 5, that is, the set original document stopper 63 is positioned at the stop position, the discharged original document stopper 64 is positioned at the retracted position, and the original document stack amount detecting means 69 is provided.
The detection member 691 is also located at the retracted position. In this state, the width regulating member 20 is moved to the front side of the second opening 16, that is, downward in FIG. 2, so that the original to be copied is placed on the original table 12 and the width regulating member 20 is moved upward in FIG. To the inner surface of the side plate 22 and the width regulating member 20.
The widthwise position of the document is regulated by the inner surface of the document. In this way, when an original having a large widthwise dimension is set on the original table 12 as described above, the original is placed in the first opening 1
4 and the second opening 16 are mounted. In this way, when a document is set on the document table 12, the first document detection sensor 21 and the second document detection sensor 23 detect that the document is set on the document table 12, and The detection signal is sent to the control means (not shown). When a copy start switch (not shown) is turned on in this state, the electromagnetic solenoid 684 of the stopper actuating means 68 is turned on.
Is biased to set document stopper 63, ejected document stopper 64, and detection member 69 of document stacking amount detection means 69.
1 is the state shown in FIG. 1, that is, the set original stopper 63 is positioned at the original separating position, and the discharged original stopper 64 is shown.
Is positioned at the regulation position, and the detection member 691 of the document stack amount detection means 69 is positioned at the detection position. Then, the pushing plate 88 is moved from the position indicated by the solid line to the position indicated by the chain double-dashed line by a moving mechanism (not shown), the copying operation is started, the suction blower 36 is driven, and the air in the vacuum chamber 26 is sucked. To be done. Further, when the second document detecting sensor 23 detects a document, the solenoid 468 is energized, so that the opening / closing valve 46 is opened and the vacuum chamber 26 and the feeding drum 40 are communicated with each other. Therefore, the front end of the lowest document among the documents placed on the document table 12 is attracted to the feeding belt 32 of the vacuum separating and feeding means 24 and also to the feeding drum 40. At this time,
The servo motor 624 of the separated air ejecting means 62 is driven to operate the blower 623, and air is ejected from the nozzle 622 toward the front end placed on the original table 20. Air is blown between the originals, and the originals are separated and the lowest original is separated. On the other hand, when the copy start switch is turned on, the drive roller 28 is rotationally driven by the drive mechanism (not shown) via the roller drive gear 39 in the direction indicated by the arrow. When the drive roller 28 rotates, the feeding belt 32 is operated in the direction indicated by the arrow. When the second document detection sensor 23 detects a document, the electromagnetic clutch 56 is energized, so that the feeding drum 40 is rotated. Therefore,
As described above, the lowest document adhering to the feeding belt 32 and the feeding drum 40 is fed to the downstream side in the conveying direction. In this way, when a document having a large width direction is placed on the document table 12, that is, when the second document detection sensor 23 detects a document, the document is placed on the side of the vacuum separating and feeding means 24. The feeding drum 40 provided is activated, and the vacuum separating and feeding means 24 and the feeding drum 4 are operated.
With 0, the lowest document is fed while being sucked over the entire width direction, so that the diagonal feeding of the document is reliably prevented.
Further, in the illustrated embodiment, when a document having a small width dimension is placed on the document table 12, that is, the second
If the document detecting sensor 23 of FIG. 2 does not detect the document, the solenoid 468 is deenergized and the opening / closing valve 46 is closed, so that the vacuum degree in the vacuum chamber 26 of the vacuum separating / feeding means 24 does not decrease. . Further, in the illustrated embodiment, when the second document detection sensor 23 does not detect a document, the electromagnetic clutch 5 is used.
Since 6 is deenergized and the feeding drum 40 is stopped, the feeding drum 40 does not rotate without a document above the feeding drum 40, so that safety can be ensured.

[0026]

Since the automatic document feeder according to the present invention is constructed as described above, it has the following effects.

That is, according to the present invention, the set original document stopper for positioning the front end of the original document placed on the original document table is provided with an actuated portion formed by bending at the upper end portion and arranged above the original document table. The stopper activating means is provided so as to be movable between a stop position where its lower end abuts against the upper surface of the document table and a lower end thereof between a document separating position with a predetermined distance above the upper surface of the document table. Is equipped with an operating shaft equipped with an operating cam that comes into contact with the lower surface of the operated portion of the set document stopper, and drive means for rotating the operating shaft. By rotating the operating shaft by a predetermined angle by the drive means, Since the set document stopper is selectively positioned between the stop position and the document separation position, the set document stopper can be positioned at the document separation position during document feeding. When air is ejected toward the front end of the set original by the air ejecting means, air is blown between the originals, the originals are separated, and the front end of the originals above the second lowest sheet is Since it is lifted above the lower end of the set document stopper, the movement of the set document stopper to the downstream side in the document conveying direction is restricted, and the document is prevented from being double-fed. As described above, in the present invention, since the set document stopper also has the function of preventing document double feeding, it is not necessary to newly provide a document separating member, so that an inexpensive automatic document feeder can be obtained.

[Brief description of drawings]

FIG. 1 is a sectional view of an automatic document feeder constructed according to the present invention.

FIG. 2 is a plan view of a main part of the vacuum document separating and feeding means provided in the automatic document feeder shown in FIG.

FIG. 3 is a cross-sectional view taken along line AA of the vacuum separating and feeding unit shown in FIG.

FIG. 4 is a cross-sectional view taken along line BB of the vacuum separating and feeding means shown in FIG.

5 is an enlarged cross-sectional view of essential parts showing a state when a document is set in the automatic document feeder shown in FIG.

FIG. 6 is an enlarged cross-sectional view of essential parts showing a document transport state of the automatic document transport device shown in FIG. 1.

7 is a front view of relevant parts showing a relationship between a set original document stopper, a discharged original document stopper, and a stopper operating means which are provided in the automatic original document feeder shown in FIG.

8 is a cross-sectional view taken along line CC in FIG.

9 is a perspective view of essential parts of a stopper actuating means and a document stacking amount detecting means provided in the automatic document feeder shown in FIG.

[Explanation of symbols]

2: Electrostatic copying machine 4: Automatic document feeder 6: Electrostatic copying machine housing 8: transparent plate 10: Document control member 12: Manuscript table 14: First opening 16: Second opening 18: a pair of guide grooves 20: Width regulation member 21: First original detection sensor 23: Second document detection sensor 24: Vacuum separating and feeding means 26: Vacuum chamber 28: Drive roller 30: Driven roller 32: feeding belt 34: Duct 36: Suction blower 39: Roller drive gear 40: Feeding drum 42: Duct 46: Open / close valve 56: Electromagnetic clutch 58: Feed drum driving gear 60: Drive shaft 61: Intermediate gear 62: Separated air ejection means 621: air chamber 622: Nozzle 623: Blower 624: Servo motor 63: Set original stopper 64: Ejected original stopper 66: Support means for set document stopper 67: Supporting means for ejected document stopper 68: Stopper operating means 681: operating axis 682: Actuating cam 683: Actuating lever 684: Solenoid 69: Document Loading Amount Detection Means 691: Detection member 692: Detector 70: Paper feed roller pair 72: document input path 74: Pair of registration rollers 76: Conveyor belt mechanism 80: Original carry-out path 82: Transport roller pair 84: Pair of transport rollers 86: discharge roller pair 88: Extruded plate

Claims (2)

(57) [Claims] 1. A document table having an opening at the front in the document transport direction.
Table and the top surface of the original table below the opening of the original table.
Arranged substantially flush with the upper surface of the draft table, with an opening on the upper surface
Vacuum chamber, winding the vacuum chamber
Holes that are arranged as a set and are operated in the document transport direction
A feeding belt equipped with an original placed on the original table
Separated air ejection means for ejecting air toward the front end of the draft
Vacuum separating and feeding means provided and on the original table
Set document stack to position the front edge of the document placed on the
And a stopper operation hand that operates the set original document stopper.
In an automatic document feeder having a step, The set document stopper isBent and formed on the upper end
It has an affected part,Placed above the document table
Stop whose bottom edge contacts the upper surface of the original table
Position and its bottom edge above the top of the document table.
It is configured to be movable between the document separation position with a fixed interval
Has been done, The stopper operating means isThe work of the set document stopper
An operating shaft equipped with an operating cam that abuts the lower surface of the working portion;
Drive means for rotating the operating shaft, the drive means
By rotating the operating shaft by a predetermined angle by
Select the document stopper at the stop position and the document separation position.
Position selectively, An automatic document feeder, which is characterized in that 2. The set original document scan at the original document separation position.
The distance between the lower end of the topper and the upper surface of the original table is 2.
The automatic according to claim 1, which is set to 0 to 3.0 mm.
Document feeder.