JP3080129B2 - Automatic document feeder and image forming apparatus having the same - 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 applicable to an image forming apparatus such as a copying machine and a laser beam printer.

[0002]

2. Description of the Related Art Conventionally, in an automatic document feeder for automatically feeding a document to a reading section of an image forming apparatus such as a copying machine, a shutter for contacting a document on a document table and receiving a leading end thereof. Is provided. The original is sent out by a feeding unit below the shutter, separated one by one by a separating unit on the downstream side, transported to the image reading unit and fixed,
The original image is fixedly read by operating the optical system.

There is also a method of reading a document image while transporting the document while the document on the document table is transported from the rear end side to an image reading unit and the optical system is fixed. In this case, the document on the document table is fed by the shutter after being moved to the shutter and feeding means on the rear end side.

[0004]

When the shutter moves the document bundle, the edge of the document may be curled upward, and such a document may not be able to move to the rear end side properly. Was.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an automatic document feeder capable of stably moving a document by a shutter for moving and reading the document even if the document is curled. is there.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has an object mounting table on which a large number of originals can be mounted, and a method of reading an original on the original mounting table from its front end. A first transport path for feeding the original document to the document reading unit, a second transport path for feeding the original document from the rear end to the original reading unit, and an entrance portion of the first transport path. , When using the first transport path,
A shutter configured to prevent a document on the document table from entering the first conveyance path, and in a state where the second conveyance path is used, the document on the document table is A shutter which constitutes a pusher for pushing out toward the second conveyance path, and when the shutter means functions as a shutter for the first conveyance path, the amount of upward projection with respect to the document table is reduced; Second
And a changing means for increasing the upwardly protruding amount with respect to the document table when functioning as a pusher for the transport path of the document.

The document table is held at a raised position when the document is fed through the first transport path, and is lowered when the document is fed through the second transport path. The changing means is configured to change an upwardly protruding amount of the shutter means with respect to the document placing table in association with lifting and lowering of the document placing table.

[0008]

According to the above construction, when a document on the document table is transported from the first transport path, the leading end of the document is aligned by shutter means having a small amount of projection, and then, for example, fed by feeding means. The document is transported to the reading unit via the first transport path.

When the original is fed from the second transport path and the original is read, the amount of projection of the shutter functioning as a pusher from the original mounting table is increased by the changing means. In this state, the shutter unit pushes and moves the document toward the second transport path, and transports the document to the reading unit via the second transport path.

Thus, even if the original table moved to the second transport path is in a curled state, the original can be stably moved to the second transport path side, and an appropriate original Feeding can be done.

Further, the original placing table is held at an upper position by an elevation driving device when the original is fed through the first transport path, and when the original is transported through the second transport path. , Held in the lowered position. And the changing means is:
In conjunction with the lowering of the document table, the shutter is held in a state in which the upward projection amount of the shutter is increased.

[0012]

[0013]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 shows an example of an image forming apparatus main body to which the present invention can be applied.

A platen glass 3 as a document reading unit, a light source 907, a lens system 9
08, a paper feeding unit 909, an image forming unit 902, and the like. Documents P are fed one by one to the platen glass 3 by the automatic document feeder 2.

The paper feeding section 909 has cassettes 910 and 911 which can store and detach sheets and are detachable from the apparatus main body 900, and a deck 913 which is arranged on a pedestal 912.
The image forming unit 902 includes a developing device 915 having a cylindrical photosensitive drum 914, a transfer charger 916, a separation charger 917, a cleaner 918, a primary charger 919, and the like. A transport device 920, a fixing device 904, a discharge roller 905, and the like are disposed downstream of the image forming unit 902.

The operation of the image forming apparatus will be described.

When a paper feed signal is output from a control device 930 provided on the apparatus main body 900, the cassette 91 is output.
The sheet S is fed from the deck 0, 911 or the deck 913. On the other hand, light reflected from the light source 907 on the original P placed on the platen glass 3 is reflected by the optical system 908.
Irradiates the photosensitive drum 914 via the. Photosensitive drum 9
14 is charged in advance by a primary charger 919, and is irradiated with light to form an electrostatic latent image,
Next, a toner image is formed by the developing device 915.

The sheet material S fed from the paper feeding unit 909
The skew is corrected by the registration rollers 910, and the skew is sent to the image forming unit 902 at a further adjusted timing. In the image forming unit 902, the toner image on the photosensitive drum 914 is transferred to the sheet S sent by the transfer charger 916, and the transferred sheet S is charged to the opposite polarity to the transfer charger 916 by the separation charger 917. Photosensitive drum 9
14.

Then, the separated sheet S is conveyed to a fixing device 904 by a conveying device 920, and
04, the unfixed transfer image is permanently fixed on the sheet S. The sheet material S on which the image is fixed is discharged from the apparatus main body 900 by the discharge roller 905.

In this way, the sheet material S fed from the paper feeding unit 909 is formed with an image and discharged.

FIG. 1 is a vertical sectional front view of the automatic document feeder 2. In the figure, a driving roller (first roller) is provided on a platen glass 3 of a copying machine main body 900.
A forward / reverse rotatable transport belt 20 wound around a driven roller 17 and a driven roller (second roller) 19 is provided.

A plurality of originals (sheets) P are placed on the original placing table 5 and are aligned in such a manner that the width direction is regulated by a pair of width regulating plates 7. The recycle lever 10 placed on the original P indicates a member for distinguishing between the original P that has not been fed and the fed original P that is discharged onto the original placing table 5 after feeding. Reference numeral 6 denotes a shutter which receives and aligns the leading end of the document P, and which retreats below the document placing table 5 during paper feeding. Reference numeral 9 denotes a half-moon-shaped feeding roller 9 which rotates at the time of paper feeding and feeds the document P from the bottom of the document P.

On the downstream side of the feed roller 9, there is provided a separation unit including a conveyance roller (forward rotation means) 11 rotating in the document feeding direction and a separation belt (reverse rotation means) 12 rotating in the document return direction. The originals P sent by the feed rollers 9 are separated and conveyed one by one. Further downstream, the large roller 13 and the sheet feeding roller 1 in contact therewith
A sheet feed roller pair 5 is provided to feed the document P onto the platen glass 3 at a predetermined timing.
The document P conveyed onto the platen glass 3 by the rotation of the conveyance belt 20 and stopped at a predetermined position is fixedly read by manipulating the light source 907 in the direction of the arrow.

A first transfer path 16 is formed by a transfer path including the separation units (first separation units) 11 and 12 and the first pair of paper feed rollers 13 and 15.

After the reading is completed, the original P
By the reverse rotation of 0, the sheet is conveyed to the flapper 25 via the conveyance path outside the large roller 13. The flapper 25 reverses the original P when reading both sides of the original P,
The document P is guided to the discharge roller pair 29 via the sheet discharge path 26 in the case of one-sided reading. 27
Denotes a sensor for detecting the document P passing through the discharge path 26. Document P discharged by discharge roller pair 29
Are placed on the original P that has not been fed on the original placing table (5), and are distinguished by the recycle lever 10.

The document table 5 is rotatable about the support shaft 4 between an inclined position shown in FIG. 1 and a horizontal position shown in FIG. 3 by an operation described later. P
Is transported to the platen glass 3 via the first transport path 16 as described above, and at the position shown in FIG.
To be transported to

At the rear end side of the original P, members similar to the above-mentioned members disposed at the front end side of the original P are provided, respectively. 37 is a guide plate, and 36 is a half-moon-shaped second member. And a feed roller 39 for feeding the original P to the second feed roller 36
, A transport roller rotating in the document feeding direction, and a separation belt 41 rotating in the document returning direction.

On the downstream side of the second separation section including the conveyance roller 40 and the separation belt 41, a second conveyance path 45 for conveying the separated document P to the platen glass 3 as a reading section is provided. I have. The second transport path 45 includes a transport roller pair 43, a relay sensor 48, a relay roller 4
6, a paper feed roller pair 47 is provided.

Between the upper roller of the pair of paper feed rollers 47 and the second roller 19 of the conveyor belt 20, the document P is guided to the platen glass 3, or the document P on the platen glass 3 is rotated. A guide member 50 is provided.

Reference numeral 51 denotes a manual feed tray for manually feeding the original P into the automatic document feeder 2, reference numeral 52 denotes a manual feed roller, and reference numerals 53 and 49 denote guide plates for the manual feed.

4 and 6, a frame 31 and a support member 32 integral with the frame 31 are fixed to both sides of the document table 5, respectively, and the support member 32 is rotatable about the support shaft 4. It has become. The bent piece 31 a provided on the frame 31 is pressed by a drive pin 35 a provided at a free end of the drive member 35 and descends. The drive members 35 are fixed to both ends of the connection shaft 33, respectively, and are rotated by a drive source such as a motor. The drive member 35 and the drive source constitute an elevation drive device that moves the document table 5 up and down. Reference numeral 21b shown in FIG. 6 indicates a hole through which the delivery roller 9 extends upward when the delivery roller 9 rotates.

When the original P is fed from the rear end side (flow reading is performed in order to execute high-speed reading), the driving pin 35a is rotated to drive the driving pin 35a.
Presses the bent piece 31 a of the frame 31. As a result, the document table 5 is moved from the inclined state of FIG.
It is rotated to the horizontal state of (c).

In FIG. 4, a support shaft 5 integral with a shutter 6 is shown.
5 is a support portion 63a integral with the block 63 (see FIG. 6).
Is mounted to be rotatable. Reference numeral 60 denotes a solenoid (changing means) for driving the shutter 6, and a pin 59 is fixed to the other end of the connecting member 61 whose one end is pivotally supported by the operating member 60a. The pin 59 is engaged with a long hole provided at a free end of the arm 57, and the arm 57 is rotatable around a support shaft 57a.

A lower end of a driven member 56 having a free end fixed to the support shaft 55 is opposed to the pin 59.
The shutter 6 is urged in a clockwise direction in FIG. 4, that is, a direction in which the shutter 6 extends from the document table 5 by a tension spring 62 having both ends locked by the shutter 6 and the connecting member 61.

When the original P on the original table 5 is transported along the first transport path 16 (to make a plurality of copies,
The shutter (shutter means) 6 functions as a normal shutter when reading in the original fixed mode.
As shown in (a), the amount of protrusion from the document table 5 is small. When a feed start signal from the control device 930 (FIG. 2) is given to the solenoid 60 to operate, the arm 57 is rotated clockwise in FIG. 4A. As a result, the driven member 56 is pressed by the pin 59 and rotates counterclockwise as shown in FIG. At the same time, when the shutter 6 integrated with the arm 57 rotates in the same direction, the shutter 6 is retracted from the upper surface of the document table 5 (FIG. 4B). In this state, when the feed roller 9 rotates, several sheets of the document P are transported to the separation units 11 and 12.

In FIG. 6, a block 63 supporting the shutter 6 is movably supported by a guide shaft 65. Reference numeral 32a denotes a guide piece which engages with and guides the protrusions 6a at both ends of the shutter 6 when the shutter 6 returns to the original position shown in the figure. In the state of FIG. As a result, the projection 6a is
a.

Reference numeral 66 denotes a motor (pulse motor) for moving the shutter 6 along the upper surface of the document table 5, and an output gear 66 a fixed to the output shaft is engaged with a pulley gear 67. . Pulley 6 of pulley gear 67
A belt 70 is wound around 7 a and the plurality of pulleys 69 a, 69 b, 69 c, and a part thereof is connected to the block 63. As a result, the shutter 6 moves in the longitudinal direction (front-back direction) of the document table 5 by rotating the motor 66 according to the length of the document P.

The original P is transferred from the rear end to the second transport path 45.
When the document is conveyed to the side, while the shutter 6 is held at the position shown in FIG. 4A, the document table 5 is lowered to the horizontal state as described above (FIG. 4C). When the guide piece 32a of the support member 32 integrated with the document table 5 rotates in the downward direction, the protrusion 6a of the shutter 6 pressed against the guide piece 32a follows the same direction (clockwise in FIG. 4). ).

As a result, the shutter 6 is moved from the original table 5
4C, the amount of protrusion of the shutter 6 is increased as shown in FIG. 4C. In this state, when the shutter 6 is driven by the motor 66 and moved to the second feed roller 36 side, the document P is conveyed in a bundle, and the second feed roller 36 and the second separation unit 40, 41, the second transport path 4
5 can be fed.

As described above, when the shutter 6 functions as a pusher, the protrusion amount of the shutter 6 is increased to curl the end (front end) of the document P placed on the document table (5). Even if there is, the end is engaged with the shutter 6 and the bundle P can be stably conveyed.

The original P fed by the second feed roller 36 and separated one by one by the separation units 39 and 40
Is transported via the second transport path 45 onto the platen glass 3 serving as a reading unit. Further, the document P is read by the light source 907A stopped at a predetermined position while being conveyed by the conveyance belt 20, and is discharged onto the document table 5 via the discharge path 26.

In order to select either the flow reading or the fixed reading, the mode is selected by operating the mode selection means. Alternatively, the mode may be automatically selected by designating the number of copies. . The mode selection means in the figure includes an operation button, and also includes other operations when automatically selected.

[0044]

As described above, according to the present invention,
When the document on the document table is transported to the reading section along the first transport path, the amount of protrusion of the shutter means functioning as a shutter with respect to the document table is reduced.
Shutter means can be provided in a narrow space of the paper feeding section. When a document is transported to the reading section via the second transport path, the document is placed at a position connected to the second transport path. In conjunction with the movement of the mounting table, the amount of projection of the shutter means functioning as a pusher is increased, so that even with a curled original, the original can be reliably pushed and moved by the shutter means, thereby stabilizing the original. Can be performed.

[Brief description of the drawings]

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

FIG. 2 is a longitudinal sectional front view showing an example of an image forming apparatus to which the automatic document feeder is applicable.

FIG. 3 is an operation diagram of the automatic document feeder of FIG. 1;

FIG. 4A is a side view of a shutter unit and a document table when a document is fed from a first conveyance path;
FIG. 2B is a diagram illustrating the operation of FIG. 1A, and FIG. 2C is a side view of the shutter unit and the document table when the document is fed from the second conveyance path.

FIG. 5A is a side view of a shutter unit and a document table when a document is transported from a first transport path.
(B) figure and (c) figure are action figures of (a) figure.

FIG. 6 is a plan view of the shutter unit and its driving unit.

[Explanation of symbols]

 P Document (Sheet) 2 Document Automatic Feeder 3 Platen Glass (Reading Unit) 5 Document Placement Table 6 First Shutter (Shutter Means) 9 First Delivery Roller 11 Transport Roller (Forward Rotation Means) 12 Separation Belt ( Reverse rotation means) 11, 12 first separating section 13 large roller 15 paper feed roller 16 first transport path 17 first roller 19 second roller 20 transport belt 26 discharge path 29 discharge roller pair 31 frame 32 support member 33 Connecting shaft 35 Drive member (elevation drive device) 36 Second feed roller 40 Transport roller 41 Separation belt 40, 41 Second separator 45 Second transport path 47 Feed roller pair 50 Rotation guide member 51 Manual feed tray 52 Manual feed roller 55 Support shaft 60 Solenoid (change means) 63 Block 66 Pulse motor 900 Image forming apparatus Body 902 image forming unit 930 control unit

────────────────────────────────────────────────── ─── Continuation of the front page (72) Wataru Kawata Inventor Canon Inc. 3- 30-2 Shimomaruko 3-chome, Ota-ku, Tokyo (56) References JP-A-5-303246 (JP, A) (58) Survey Field (Int.Cl. ⁷ , DB name) G03G 15/00 107 B65H 3/40 B65H 83/00-85/00 G03B 27/58-27/64 H04N 1/00-1/00 108

Claims (3)

(57) [Claims] An original placing table on which a large number of originals can be placed; a first transport path for feeding the originals on the original placing table to a document reading section from a front end thereof; A second transport path for feeding the document from the rear end thereof to the document reading unit; and a second transport path that is disposed at an entrance of the first transport path and uses the first transport path. A shutter configured to prevent a document on the table from entering the first transport path, and in a state in which the second transport path is used, the document on the document table is moved to the second transport path. A shutter means that constitutes a pusher that pushes out toward the conveyance path, and when the shutter means functions as a shutter for the first conveyance path, the amount of upward projection with respect to the document table is reduced, and the second Push for transport route When functioning as, an automatic document feeder, characterized in that it comprises a changing means for such upwardly projecting amount increases with respect to the document table. 2. The document placement table is held at a raised position when a document is fed through the first conveyance path, and is lowered when a document is fed through the second conveyance path. 2. The document according to claim 1, further comprising a lifting drive device that moves the document mounting table, wherein the changing unit changes an upwardly protruding amount of the shutter unit with respect to the document mounting table in association with lifting and lowering of the document mounting table. Automatic feeding device. 3. An image forming apparatus, comprising: an image forming unit; and the automatic document feeder according to claim 1 or 2.