JP3400849B2 - Sheet feeder and automatic document feeder using 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 a sheet feeding apparatus applicable to an image forming apparatus such as a copying machine and a laser beam printer, and an automatic document feeding apparatus using the sheet feeding apparatus.

[0002]

2. Description of the Related Art Conventionally, in an automatic document feeder for automatically feeding a document (sheet) to a reading portion of an image forming apparatus such as a copying machine, the document is fed from a document table and separated one by one. A document (sheet) is conveyed to a platen glass (reading unit) of the image forming apparatus by a pair of paper feed rollers including a large roller and a paper feed roller that is in contact with the large roller to read an original image. The read document is discharged onto the document mounting table by a pair of discharge rotators via a discharge path including the outside of the large roller.

FIG. 10 shows a pair of discharge rotating bodies in a conventional device. With the plurality of ribs 97 provided on the cover 95 of the automatic document feeder and the lower guide member 94,
A discharge path 26 is configured to convey the document after reading the document image. The document P conveyed on the discharge path 26 is
The sheet is discharged onto the document placing table by the pair of discharging rotating members 29. FIG. 11 shows an upper cover 95 and a lower cover 96 that cover the outside of the large roller 13 that constitutes the pair of paper feed rollers. The original P conveyed from a reading unit (not shown) is conveyed through a discharge path constituted by the large roller 13 and the covers 95 and 96, and then discharged by the discharge rotating body pair 29.

The upper cover 95 has a plurality of ribs 97, as shown in FIG. 12, and is openable and closable around a support shaft 95a. Similarly, the lower cover 96 also has a plurality of ribs 99, and can be opened and closed about the support shaft 96a. The connecting portions of both covers 95 and 96 need to be close to each other in order to open and close the covers and to smoothly guide the document P. For this reason, for example, an end portion of the rib 99 of the lower cover 96 is illustrated. The protrusions are formed as shown.

[0005]

However, in the above-mentioned conventional sheet feeding device, the pair of discharge rotating members 29 is used.
If the original P ejected by means of plain paper is plain paper, it is directed toward an original placing table (not shown) by the end portions of the ribs 97 and is ejected smoothly. Before and after the rotating body pair 29, the ribs 97 are in strong contact with each other. Therefore, there is a problem that the load of the driving motor for conveying the document P is increased, and when the rear end of the document P passes through the discharge rotating body pair 29, the rib 97 is struck and the bounce noise is increased. there were.

Further, the ribs 97, 9 of both covers 95, 96
The protrusion 99a is formed on one rib 99 in order to reduce the gap a of the sheet 9. Therefore, when the jammed document P is removed by opening the cover, the document P is caught by the protrusion and damaged. There was a problem of doing.

According to the present invention, there is provided a sheet feeding device capable of discharging a thick paper document without imposing an excessive load on a drive motor and producing a large bounce noise, and an automatic document feeder including the same. It is intended to be provided. Further, when a jam occurs due to the discharge path, the original document is removed without damaging the original document.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and is provided with a discharging rotating body for discharging a sheet to a tray, and discharging the sheet from the discharging rotating body to the tray. In the sheet feeding device, a movable guide member that is disposed in the sheet guide path upstream of the discharge rotating body and is movably supported, and a holding member that holds the movable guide member at a position where a normal sheet guide path is formed. Means and
And a deflection unit that configures a curved sheet guide unit that deflects and bends the direction of the sheet discharged from the discharge rotating body, and the direction is changed by the direction changing unit to bend. The movable guide member is moved in a direction that absorbs the bending by the bending of the rear end portion of the sheet.

[0009]

According to the above construction, the original document conveyed through the discharge path is discharged onto the tray by the pair of discharge rotators. When the original is plain paper or thin paper, the rear end of the original is guided by a movable guide member that forms a normal sheet guide path, that is, a discharge path, and is discharged to the tray.

In the case of ejecting a thick paper document, the rear end of the document is guided and ejected by the movable guide member located at a position escaped by the rigidity of the document. The movable guide member retracts and absorbs the bending of the original, which prevents an increase in the load on the drive motor that conveys the original, and also causes a bounce noise when the rear end part comes out of the pair of discharge rotating bodies. Can be suppressed.

[0011]

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 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 automatic document feeder using the sheet feeding apparatus of the present invention can be applied.

The copying machine main body 900 includes a platen glass 3 as a document reading section, a light source 907, and a lens system 9.
08, a paper feeding unit 909, an image forming unit 902, and the like. Documents P are fed to the platen glass 3 one by one by the automatic document feeder 2.

The paper feeding unit 909 has cassettes 910 and 911 that accommodate sheets and can be attached to and detached from the apparatus main body 900, and a deck 913 arranged in a pedestal 912.
The image forming unit 902 is provided with a developing device 915 having a cylindrical photosensitive drum 914 built therein, a transfer charger 916, a separation charger 917, a cleaner 918, a primary charger 919, and the like. A conveying device 920, a fixing device 904, a discharge rotating body 905, and the like are arranged on the downstream side of the image forming unit 902.

The operation of this image forming apparatus will be described.

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

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

Then, the separated sheet S is conveyed to the fixing device 904 by the conveying device 920, and the fixing device 9
By 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 rotating body 905.

In this way, the sheet material S fed from the paper feeding section 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 the platen glass 3 of the copying machine main body 900.
A forward / reverse rotatable conveyor belt 20 wound around a 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 aligned in a widthwise direction by a pair of width regulating plates 7. The recycle lever 10 placed on the document P indicates a member that distinguishes the unfed document P from the fed document P discharged onto the document mounting table 5 after being fed. Reference numeral 6 denotes a shutter that receives and aligns the leading edge of the document P, and retracts below the document table 5 at the time of sheet feeding. Reference numeral 9 denotes a half-moon-shaped feed roller 9, which rotates at the time of paper feeding and feeds the document P from the lowermost side of the document P.

On the downstream side of the feed roller 9, there is provided a separation section composed of a conveyance roller (normal rotation means) 11 rotating in the document feeding direction and a separation belt (reverse rotation means) 12 rotating in the document returning direction. The original P sent by the sending roller 9 is separated and conveyed one by one. Further on the downstream side, the large roller 13 and the paper feed roller 1 in contact with the large roller 13 are provided.
A pair of paper feed rollers 5 is provided to feed the document P onto the platen glass 3 at a predetermined timing.
The original P that has been conveyed onto the platen glass 3 by the rotation of the conveyor belt 20 and stopped at a predetermined position has its original image fixedly read by operating the light source 907 in the direction of the arrow.

A first conveying path 16 is constituted by the conveying path including the separating portions (first separating portions) 11 and 12 and the first paper feed roller pairs 13 and 15.

The original P after completion of reading is conveyed by the conveyor belt 2
By the reverse rotation of 0, it 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, and the platen glass 3
In the case of one-sided reading, the document P is guided to the discharge rotating body pair 29 via the sheet discharge path 26. 27
Indicates a sensor for detecting the document P passing through the sheet discharge path 26. The document P discharged by the pair of discharge rotators 29 is placed on the document P not yet fed on the document mounting table (5), and is distinguished by the recycle lever 10.

The document table 5 is rotatable about the support shaft 4 between the tilted position shown in FIG. 1 and the horizontal position shown in FIG. 3 by the operation described later. At the position shown in FIG. P
Are conveyed to the platen glass 3 through the first conveying path 16 as described above, and at the position of FIG. 3, the platen glass 3 is conveyed from the rear end side of the document P through the second conveying path 45.
To be transported to.

On the rear end side of the original P, the same members as the above-mentioned members arranged on the front end side of the original P are provided, 37 is a guide plate, and 36 is a half-moon shaped second. Of the second feeding roller 36.
The reference numeral 40 denotes a weight which is pressed against, a conveying roller 40 which rotates in the document feeding direction, and 41 a separation belt which rotates in the returning direction of the document P.

A second conveying path 45 for conveying the separated original P to the platen glass 3 as a reading portion is provided on the downstream side of the second separating portion including the conveying roller 40 and the separating belt 41. There is. In the second transport path 45, the transport roller pair 43, the relay sensor 48, the relay roller 4
6, a pair of paper feed rollers 47 are provided.

Between the upper roller of the paper feed roller pair 47 and the second roller 19 of the conveyor belt 20, a rotation for guiding the original P to the platen glass 3 or guiding the original P on the platen glass 3 is performed. A guide member 50 is provided.

Reference numeral 51 is a manual feed tray for manually feeding the original P into the automatic document feeder 2, 52 is a manual paper feed roller, and 53 and 49 are guide plates for the manual original.

In FIGS. 4 and 6, a frame 31 and a supporting member 32 integral with the frame 31 are fixed to both sides of the document table 5, and the supporting member 32 is rotatable around the support shaft 4. It has become. The bent piece 31a provided on the frame 31 is pressed by the drive pin 35a provided at the free end of the drive member 35 to descend. The drive member 35 is fixed to both ends of the connecting shaft 33, and is rotated by a drive source such as a motor.

The driving member 35 and the driving source constitute an elevating and lowering device for moving the document placing table 5 up and down. Reference numeral 32b shown in FIG. 6 indicates a hole for the delivery roller 9 to extend upward when the delivery roller 9 rotates.

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

In FIG. 4, the support shaft 5 integrated with the shutter 6 is provided.
5 is a support portion 63a integrated with the block 63 (see FIG. 6).
It is rotatably attached to. 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 actuating member 60a. The pin 59 engages with a long hole provided at the free end of the arm 57, and the arm 57 is rotatable about the support shaft 57a.

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

When the original P on the original table 5 is conveyed through the first conveying path 16 (in order to make a plurality of copies,
The shutter (shutter means) 6 functions as an ordinary shutter (for reading in the original fixing method).
As shown in (a), the amount of protrusion from the document table 5 is small. When a paper 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. 4 (a). As a result, the driven member 56 is pressed by the pin 59 and rotates counterclockwise as shown in FIG. At the same time, the shutter 6 integrated with the arm 57 rotates in the same direction, so that the shutter 6 is retracted from the upper surface of the document table 5 (FIG. 4B). In this state, the feeding roller 9 is rotated, so that several sheets of the document P are conveyed to the separating units 11 and 12.

In FIG. 6, the block 63 supporting the shutter 6 is movably supported by a guide shaft 65. Reference numeral 32a denotes a guide piece that 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 protruding portion 6a becomes the guide piece 32.
It is in pressure contact with a.

Reference numeral 66 denotes a motor (pulse motor) for moving the shutter 6 along the upper surface of the document placing table 5, and an output gear 66a fixed to its output shaft meshes 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 of the belt 70 is connected to the block 63. As a result, the shutter 6 is moved in the longitudinal direction (front-back direction) of the document mounting table 5 by rotating the motor 66 according to the length of the document P.

The original P is fed from the rear end to the second conveyance path 45.
When the sheet is conveyed to the side, the document table 5 is lowered horizontally as described above with the shutter 6 held at the position shown in FIG. 4A (FIG. 4C). When the guide piece 32a of the supporting member 32 integrated with the document placing table 5 is rotated in the descending direction, the protrusion 6a of the shutter 6 which is pressed against the guide piece 32a follows the same direction (clockwise in FIG. 4). ) Rotate to.

As a result, the shutter 6 is moved to the original placing table 5
By rotating the shutter 6 in the clockwise direction relative to the above, the projection amount of the shutter 6 is increased as shown in FIG. In this state, the shutter 6 is driven by the motor 66 and moved to the second delivery roller 36 side, so that the documents P are conveyed in a bundle, and the second delivery roller 36 and the second separating unit are conveyed. 40, 41 for the second transport path 4
It is possible to feed to 5.

In this way, when the shutter 6 functions as a pusher, the amount of projection of the shutter 6 is increased to curl the end portion (tip portion) of the document P placed on the document placing table (5). Even if there is, the end portion is engaged with the shutter 6, so that the bundle of documents P can be stably conveyed.

Documents P fed by the second feeding roller 36 and separated one by one by the separating units 39 and 40.
Is conveyed onto the platen glass 3 which is the reading section via the second conveyance path 45. Further, the document P is fed by the light source 907A stopped at a predetermined position while being transported by the transport belt 20, and is discharged onto the document table 5 via the discharge path 26.

It should be noted that, although either the flow reading or the fixed reading is selected by operating the mode selecting means, it may be automatically selected by instructing the number of copies. . The mode selection means in the figure includes an operation button and other operations in the case of being automatically selected.

Next, FIG. 7 shows a pair of discharge rotating bodies as a sheet feeding device.

The downstream side of the discharge path 26 is constituted by a plurality of ribs 97 of the upper cover 95 and a guide member 94. On the discharge port side of the rib 97, a deflecting portion (diverting means) 97a for deflecting the direction of the discharged document (sheet) P to the document placing table (tray) 5 is formed (curved downward).
And forms a curved sheet guide path. The pair of discharge rotors 29 arranged in the curved sheet guide path are
The upper roller 29a and the lower roller 29b that is in pressure contact with this
It consists of

A notch 93 is formed in the rib 97 on the upstream side of the pair of discharge rotors 29, and a movable guide member 90 rotatable about the upstream side as a fulcrum 91 is arranged in the notch 93. It is set up. This movable guide member 9
0 is biased toward the guide member 94 by the compression spring 92, and the free end thereof is engaged with the stopper (holding means) 27b fixed to the rib 97 and is held at a position forming the discharge path.

The guide surface 90a and the guide surface 97b are substantially flush with each other. At the entrance side of the movable guide member 90, the discharge path 26 is provided so that the document (sheet) P is not caught.
It is bent so that it is in a retracted position.

Further, the movable guide member 90 may be formed of a single plate, and a plurality of ribs may be formed on the guide surface 90a to reduce the conveyance resistance of the document P, or a plurality of ribs may be formed. The divided lever-shaped members may be assembled with a space therebetween to form an integral shape.

When the original P conveyed on the discharge path 26 is plain paper, the rear end of the original P is in the original position in which it is engaged with the stopper 27b when moving on the upstream side of the exit roller pair 29. It is guided by the movable guide member 90 and the guide member 94, and is ejected to the document placing table (tray) 5 by the ejection rotating member pair 29.

When the original P is thick paper, when the rear end of the original P moves on the upstream side of the pair of discharge rotators 29 and the rear end reaches the movable guide member 90, the movable guide member is moved by the rigidity of the rear end. 90 is moved to the upper retracted position (see FIG. 8). As a result, the rear end portion of the document P has the discharge rotating body pair 29.
When passing through, the bending of the rear end is caused by the movable guide member 90.
It is absorbed by the retreat of and the bending of the rear end is suppressed to a small level. Therefore, the friction between the document P and the movable guide member 90 is reduced.

As a result, an increase in the load on the drive motor for conveying the original P is suppressed, and an increase in the bouncing sound when the rear end of the original P comes out of the discharge rotating body pair 29 is suppressed. Stable discharge is performed.

[0052]

Next, the upstream side of the discharge path 26 is constituted by the large roller 13 and the upper and lower covers 95 and 96 as shown in FIG. In this example, the support shaft 95a of the upper cover 95 and the support shaft 96a of the lower cover 96 are arranged at positions where they enter each other. As a result, the ribs of both covers for guiding the original P are connected at the overlapping portion 98 shown by the diagonal lines, and the original P can smoothly pass through both covers 95 and 96 without being caught at the connecting portion. it can. Then, the covers 95 and 96 are attached to the chain line position 95A,
Even when the jammed document P is removed by opening to 96A, the protrusion 99a provided on the conventional cover (see FIG. 1).
Since 1) does not exist in the covers 95 and 96, the document P can be removed without damage.

In the present invention, the movable guide member 90 may move even on thin paper. Further, the present invention is not limited to the sheet discharging section, and can be applied in the sheet conveying path as long as the sheet is curved and fed.

[0055]

As described above, according to the present invention,
A movable guide member is arranged on the upstream side of the discharge path so that when the sheet is discharged, it can move in a direction away from the discharge path. Deflection of the rear end portion can be suppressed to be small, and an increase in load on the drive motor for sheet conveyance and an increase in bounce noise when the sheet passes through the discharge rotating body pair can be suppressed.

[Brief description of drawings]

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

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

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

FIG. 4A is a side view of the shutter section and the document mounting table section when a document is fed from the first transport path.
(B) is an operation view of (a), and (c) is a side view of a shutter section and a document placing section when a document is fed from a second transport path.

FIG. 5A is a side view of the shutter section and the document placing section when the document is conveyed from the first conveyance path.
(B) figure, (c) figure are action diagrams of (a) figure.

FIG. 6 is a plan view of the shutter section and its drive section.

FIG. 7 is a front view of a pair of discharge rotating bodies as a sheet feeding device.

FIG. 8 is an operation diagram of FIG.

FIG. 9 is a vertical sectional front view of the large roller and the upper and lower cover portions.

FIG. 10 is a vertical cross-sectional front view of a conventional pair of discharge rotating bodies.

FIG. 11 is a vertical sectional front view of a conventional large roller and upper and lower cover portions.

FIG. 12 is likewise a perspective view of the upper and lower covers.

[Explanation of symbols]

P manuscript (sheet) 2 Automatic document feeder 3 Platen glass (reading section) 5 Original placing table 6 First shutter (shutter means) 9 First delivery roller 11 Transport rollers (forward rotation means) 12 Separation belt (reversing means) 11,12 First separation part 13 Large roller 15 Paper feed roller 16 First transport route 17 First Roller 19 Second roller 20 conveyor belt 26 Discharge route 27b Stopper (holding means) 29 Discharge rotor pair 31 frames 32 Support member 33 Connection shaft 35 Drive member (elevation drive device) 36 Second delivery roller 40 transport rollers 41 separation belt 40,41 Second separation section 45 Second transport route 47 paper feed roller pair 50 Rotation guide member 51 bypass tray 52 Manual feed roller 55 spindle 60 solenoid (change means) 63 blocks 66 pulse motor 90 Movable guide member 91 fulcrum 92 Compression spring 93 Notch 94 Guide member 95 Top cover 96 Lower cover 97 Ribs on top cover 99 Lower cover rib 95a, 96a spindle 900 Image forming apparatus main body 902 image forming unit 930 controller

─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Tomohito Nakagawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Kazuhiro Matsuo 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inside the corporation (56) Reference JP 62-191332 (JP, A) JP 2-204270 (JP, A) Actual development 1-70746 (JP, U) Special table 5-503494 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B65H 29/52 B65H 29/22

Claims (3)

(57) [Claims] 1. A discharge rotating body for discharging a sheet onto a tray
The sheet is ejected from the ejection rotor to the tray.
In the sheet feeding device It is arranged in the sheet guide path on the upstream side of the discharge rotating body and
A movable guide member movably supported, The movable guide member is used to form a normal sheet guide path.
Holding means for holding theBy changing the direction of the sheet discharged from the discharge rotating body
Bending means for making a curved sheet guide portion
When, Equipped withWhen the direction is changed by the changing means to bend, the front
Due to the bending of the rear end of the sheet, the movable guide member
Is designed to move in the direction that absorbs the deflection, A sheet feeding device characterized in that 2. The tray is an original placing table, and a feeding side conveying means for conveying the original to the reading section, and a discharge side conveying path for discharging the original from the reading section toward the original placing table. An automatic document feeder including the sheet feeding device according to claim 1 disposed in the discharge side conveyance path. 3. An image forming apparatus, comprising: an image forming section; and the sheet feeding device according to claim 1 or the automatic document feeding device according to claim 2.