JPH0543103A - Automatic document feeder - Google Patents

Abstract

PURPOSE:To increase significantly the number of documents being treated per hour by conveying the documents in a first out system by a paper feed means while superpos ing the following document upon the untreated surface side of the preceeding document on a platen, and providing a separating means to separate the following document from the preceeding document according to discharge operation for the already treated document. CONSTITUTION:A regist roller 451 forming a paper feed means and a conveyor belt 13 as a conveying means are constituted so that the latter becomes faster than the former in the conveying speed, and constitute a separating means to separate a preceeding document from a following document. Furthermore, the paper feed directional tip in a part of the following document is superposed upon the untreated surface side of the preceeding document on a platen by a paper feed means, and the document is conveyed in a first-out system. In the case when conveyance is started, linear velocity of the conveyor belt 13 is larger than peripheral velocity of the regist roller 451, and in spite of advancing on a conveying passage R2 simultaneously, since a speed of the preceeding document unrestricted by the regist roller 451 is faster than the following document, the both documents are gradually separated, so that the preceeding document is discharged speedily into a paper discharge tray 61 from a paper discharge unit 50.

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 for automatically feeding and discharging a document on a platen of an image forming apparatus such as a copying machine.

[0002]

2. Description of the Related Art In this type of automatic document feeder, documents must be exchanged at high speed according to the processing speed of the image forming apparatus.

For this reason, the conventional automatic document feeder for high speed corresponds to the speedup by so-called first feeding of the next document to be put on standby before the platen of the image forming apparatus while the next document is being processed. ing.

[0004]

However, in the first-out process of making the next original document stand by before the platen of the image forming apparatus during the processing of the previous original document, a gap is inevitably formed between the preceding original document and the next original document when exchanging the original document. However, the transport time of the document corresponding to this gap was lost, and the speed could not be sufficiently increased.

In view of the above points, the present invention allows the leading original to stand by so that the leading edge of the next feeding original overlaps the non-processing side of the leading original set on the platen, and the next feeding original is advanced by the discharging operation of the leading original. It is an object of the present invention to provide an automatic document feeder that separates a document and sets a document to be sent next on a platen, which is fast in document replacement processing.

[0006]

In order to achieve the above object, according to the present invention, a sheet is fed between a sheet feeding unit for feeding an original and a platen of an image forming apparatus to be processed and processed. In an automatic document feeder including a conveying unit that sends the document later and a sheet discharging unit that receives the document from the conveying unit and discharges the document, the sheet feeding unit applies a sheet to the non-processing side of the preceding document on the platen. In addition to stacking the originals to be conveyed in advance, the separating means is provided to separate the next original from the preceding original by discharging the processed original.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An automatic document feeder applied to a copying machine will be described below with reference to the drawings.

As shown in FIG. 1, the automatic document feeder F is placed on the platen P of the copying machine M and has an outer shape of a substantially square shape, and is compact so as to fit within the upper surface profile of the copying machine M. It is configured.

As shown in FIGS. 1 and 2, an automatic document feeder F
Is a conveying means for covering a certain area corresponding to approximately half of the platen P of the copying machine M, for example, the conveying section 10, a platen cover section 20 for covering the remaining area of the platen P, and an upper portion of the platen cover section 20. Document tray unit 3 provided
0, a separating / feeding unit 40 that is a paper feeding unit that separates and feeds the document set on the document tray unit 30 toward the platen P, and an exposed document conveyed by the conveying unit 10 to receive the platen P. A paper discharge unit 50 for discharging the paper from the paper, a paper discharge tray unit 60 for storing the documents discharged by the paper discharge unit 50, and a hinge unit 70 for supporting the automatic document feeder F above the platen P so as to be openable and closable. , And a drive / control unit 80.

FIG. 18 shows the automatic document feeder F in FIG.
Shows a state in which the platen P is opened upward,
A valid reading range (reading section T: length X-Z) is defined on the upper surface of the platen P, and one end of the reading section is set as a reading reference point X. At the time of copying, one end of the document D is aligned with the reference point X so that a copy corresponding to the document can be obtained.

The reading unit T corresponds to the maximum size that can be copied, and is shown by a chain line in the drawing. For example, A3
The size (297 mm x 420 mm) is the maximum size that can be copied,
Here, A3 size is a large size (large size or L size), and A4 size (210 mm × 297 mm) is a small size (S
Size). Therefore, the total length (X
-Z) is for a large size original (L size original), and half (between XY) is for a small size original (S size original). In FIG. 18, the small-sized document D is positioned in the reading section T in accordance with the reference point.

Further, as shown in FIG. 1, the automatic document feeder F is provided with two drive motors M1 and M2.

The drive motor M1 is drivingly connected to the separating / feeding unit 40, and the driving motor M2 is drivingly connected to the conveying unit 10. However, although the registration roller 451 described later is connected to the drive motor M2 in this embodiment, it is assumed that the registration roller 451 belongs to the category of the separating / feeding unit 40 as a sheet feeding unit.

The device F is provided with several sensors. Of these, as shown in FIG. 1, the sensor S1 is an empty sensor for detecting the presence or absence of a document set on the document tray section 30. Further, the sensor S2 is a registration sensor provided on the way of the conveyance path for conveying the original separated into one sheet by the separating / feeding unit 40 to the platen P and detecting the leading edge or the trailing edge of the original passing through the conveyance path. is there. Further, the sensor S3 is a switchback sensor that detects the leading edge or the trailing edge of the document conveyed in the paper discharge unit 50.

As shown in FIG. 5, the sensor S4 is a photo sensor for detecting the rotation amount of the interrupter 871 provided on the output shaft 86 of the drive motor M2. The sensor S5 is provided on the hinge portion 70 as shown in FIG.
The automatic document feeder F detects with respect to the copying machine M whether the platen P is in the open state with the platen P open, or as shown in FIG.

Next, the details of the configuration of each part will be described.

The document tray section 30 is shown in FIGS. 9 to 11, and a document tray 31 on which a document is placed, a pair of side end guides 32L and 32R for regulating the side ends of the document set on the document tray 31. It is composed of various types of sub-tray.

FIG. 9 shows the original sub-tray 34a.
And the discharge sub-tray 34b are integrated with a sub-tray body 34 formed by bending a thin rod member.

With such a configuration, the original sub-tray 3
By pulling out 4a, at the same time, the paper discharge sub-tray 34
b is also pulled out at the same time, and when processing the L-size document, forgetting to pull out the paper discharge sub-tray 34b, and as shown in FIG. 12, the leading edge of the document comes from the paper discharge tray 61 side to the document tray 31.
It is possible to prevent an accident that the paper drips to the side and falls on the document tray 31 in some cases.

In the structure shown in FIG. 10, the document sub-tray 35, one end of which is connected to the shaft 351, and the paper discharge sub-tray 36, which is connected to the shaft 361, can be integrally projected and retracted through the connecting member 37. It was made like this. That is, the pinion 352 fixed to the shaft 351 is meshed with one rack portion 371 of the coupling member 37,
The pinion 362 fixed to the shaft 361 meshes with another rack portion 372. Then, for example, when the original sub-tray 35 is rotated clockwise to project as shown in the figure,
The coupling member 37 is moved leftward in the drawing by the clockwise rotation of the pinion, and the rack portion 372 rotates the pinion 362 clockwise. Then, the paper discharge sub-tray 36 is set in the same manner as the document sub-tray 35, and the paper discharge tray 61 is
Can be projected outward from.

Further, in FIG. 11, the document sub-tray 38 and the paper discharge sub-tray 39 are connected by a connecting wire 384 so that they can integrally project and retract.

On the original sub-tray 38 side, a locking projection 38a is provided so as to hold the protruding position when it is pulled out, and a locking member 381 that engages with the locking projection 38a is a stationary member of the apparatus F. It is fixed to. Further, a retracting spring 391 for constantly urging the member 39 toward the retracted side is disposed on the side of the paper discharge sub-tray 39.

Both sub-trays 38 and 39 are connected at their rear ends by a connecting wire 384,
The connecting wire 384 bypasses the wire guides 382 and 383 formed of an even number of rod members or roller members. It is important that the number of such wire guides is always an even number, and four or more wire guides can be formed depending on the arrangement positions of both sub-trays 38 and 39. However, in the case of an odd number, the moving directions of both sub trays are opposite to each other.

An original feeding path R1 for guiding the separated originals to the platen P from a predetermined position of the platen P (the center Y point of the reading section T) is formed in the separating and feeding section 40 as a sheet feeding means. The document feeding path R1 is provided with a guide plate 410,
It is partitioned by 411. And the document feeding path R1
Separation and feeding means are arranged along. That is, the pickup roller 42 is provided on the entrance side of the feeding path R1 so as to be movable back and forth in the document tray 31, and each guide plate 410,
From 411, the paper feed roller 43 and the separation belt 44 are connected to the feeding path R.
1 are in contact with each other and are arranged so as to overlap each other. Also, the feeding path R
Registration roller 451 and pinch roller 45 on the exit side of 1.
2 are provided facing each other.

The exit portion of the feeding path R1 is located substantially at the center (point Y) of the reading portion T defined on the upper surface of the platen P.

A guide plate 41 is provided at the entrance of the feeding path R1.
Document stopper 46 that can be moved forward and backward with respect to 1
And a sensor lever 47 that cooperates with the empty sensor S1 to detect the presence / absence of a document on the document tray 31, and is provided between the paper feed roller 43 and the registration roller 451 in the feeding path R1. A registration sensor S2 is provided.

A document stopper 46, a pickup roller 42, a paper feed roller 43, which are provided along the feeding path R1,
As shown in FIG. 4, the separation belt 44 is configured to rotate / rotate the power from the drive motor M1 in a predetermined direction via belt drive transmission means 810, 811, a plurality of gears G, and the like.

Assuming that one original is pulled out from the original tray 31 and sent to the feeding path R1, the rotation (normal rotation) of the drive motor M1 is transmitted to the shaft 831 via the gears G2, G3, and G4. The rotation of the shaft 831 causes the drive transmission member 8 to rotate.
32 is driven to rotate the shaft 833 in a predetermined direction. Then, since the document stopper 46 moves to the position shown by the chain line in FIG. 2, the document on the document tray 31 can be separated and fed.

Further, the pickup roller 42 has a shaft 82 for holding the sheet feeding roller 43 by means of a swing arm member 821.
Since it is pivotally supported by the lever 836, the lever 836 is fixed to the shaft 831 and comes into contact with the swing arm member 821.
Rotation causes the swing arm member 821 to rotate downward toward the document and contact the surface of the document.

Further, the normal rotation of the drive motor M1 is determined by the gear G.
It is transmitted to the shafts 82 and 84 via 1, G5, G6, and G7 to rotate the paper feed roller 43 and the separation belt 44 in mutually different directions. A one-way clutch 822 is incorporated in the gear G7, and even if the rotation of the gear G7 is stopped, when the document is forcibly conveyed forward, the paper feed roller 4
3 is adapted to rotate following the forward movement of the document.

The gear G6 also has a one-way clutch 823.
Even if the rotation of the gear G5 is stopped, when the document is forcibly conveyed to the front, the separation belt 44 rotates following the advance of the document.

Further, the gear G1 also has a one-way clutch 824.
When the drive motor M1 rotates in the reverse direction, the gear G1 idles, and the drive force is not transmitted to the rollers 42 and 43 and the separation belt 44, but the drive force is applied to the document stopper 46 and the lever 836. This is transmitted, and the drive motor M1 is rotationally driven in the direction opposite to that in the normal rotation.

By the structure of the separating and feeding section 40 described above,
When the drive motor M1 rotates normally, the pickup roller 42
Only the paper feed roller 43 rotates in the forward direction (original conveying direction), and the separation belt 44 rotates in the reverse feeding direction. As a result, the documents placed on the document tray 31 are fed one by one to the feeding path R1.
Transport from the entrance to the exit.

When the drive motor M1 rotates in the reverse direction, the lever 836 rotates to separate the pickup roller 42 from the surface of the original.

The original conveying section 10 as a conveying means is an endless belt-shaped conveying belt 13, a pair of pulleys 11 and 12 for driving the conveying belt 13 so as to be able to rotate forward and backward, and the conveying belt 1.
3 and a plurality of press rollers 14 for pressing the platen P against the platen P. Further, the document transporting section 10 has a size sufficient to cover approximately half (between X and Y) of the L size document from the reading reference point X side on the upper surface of the platen P. That is, the conveyor belt 13 is provided at the exit of the feeding path R1, and forms a conveying path R2 between the conveyor belt 13 and the platen P. The entrance of the conveyance path R2 (the exit of the feeding path R1) is located at substantially the center (point Y) of the reading section T, and the exit is at the reading reference point X defined at the downstream end of the reading section T in the document feeding direction. It is almost located.

Here, the pulley 11 will be described with reference to FIGS.
The detailed configuration will be described.

In FIG. 21, the pulley 11 is an arm shaft 16
It is pivotally supported at the tip of a pulley shift arm 15 which is pivotally supported by the. And the pulley shift arm 1
5 is vertically tensioned by an upper spring 18 and a lower spring 19, and is normally in a lower normal position by the lower spring 19 as shown in FIG. On the other hand, the upper spring 18 is coupled to the shaft end of the shift solenoid 17 and moves upward as shown in FIG. 19 when the shift solenoid 17 is excited.

As shown in FIG. 19, even if the pulley 11 is lifted up by the excitation of the solenoid 17, the position of the press roller 14 is not changed, and the conveyor belt 13 is moved to the platen P.
Hold it on top.

However, when the document is fed, the document shown in FIG.
As described above, the belt pulley 11 is lifted as indicated by the upward arrow A1, and when the L size original is inserted under the platen cover 21, the belt pulley 11 moves upward as shown in the figure. Then, the gap g is made sufficiently large.

When the original is set on the platen P, the belt pulley 11 descends in the direction of the arrow A2 as shown in FIG. 20 to make the gap g substantially zero.

The end 21a of the platen cover 21 is shown in FIG.
It is sharply cut like the above and is suitable for removing gaps.

If the end 21a of the platen cover 21 is sharply cut as shown in the figure, the shadow of the platen cover 21 due to the illumination lamp of the copying machine M is less likely to be formed. In order to prevent the shadow of the end of the platen cover 21 in the irradiation direction of the illumination lamp, the end 21a side may be illuminated, for example, from the lower left of FIG. 19 (arrow L in FIG. 8). desirable.

The original feeding section 10 allows the feeding path R1.
The document discharged from the exit of the document can be conveyed to the reference point X of the reading section T, or can be conveyed in front of the reference point X and ejected, or can be conveyed in the opposite direction.

As shown in FIGS. 2 and 6, the document feeder 1
Behind the exit of 0 (reference point X), the document transport unit 10
A paper discharge section 50 is provided in series.

The paper discharge section 50 has a pair of side plates 58, and a pair of pulleys 52 and 53, and a rolling roller 54 which rolls on the conveyor belt 13 and transmits a driving force.

A paper discharge belt 5 is provided between the pulleys 52 and 53.
1 is stretched, and the driving force of the rolling contact roller 54 is transmitted to the pulley 53 via a gear mechanism. Further, guide members 55 and 56 for guiding the document discharged from the exit of the conveyance path R2 to the discharge tray unit 60 are provided.
A paper discharge path R3 for guiding the document sent from the document transporting section 10 is formed between 5 and 56.

However, the rolling contact roller 54 is used as the conveyor belt 13.
The driving force in the sheet discharging direction from the sheet is transmitted, but the driving force at the time of reverse feeding is not transmitted by the one-way clutch provided inside.

A leaf spring member 57, one end of which is fixed to the guide member 55 and the other end of which presses the document against the paper discharge belt 51, is provided at a position away from the facing portion of the paper discharge belt 51. The pulleys 52 and 53 are entirely made of a low-friction material, and a high-friction ring member 59a (59b) is fitted in the central portion as shown in FIG. The part that slides is formed on the ribs 52a (53a), which has a large pressing force against the document, and at the time of paper ejection which is often seen when sticking to the cylindrical surface of the pulley as in the past. I was able to eliminate the phenomenon of the rear end remaining.

The contact roller 54 is biased directly by a spring member (not shown) on the surface of the conveyor belt 13 at a position facing the driven pulley 12.

The discharge tray 61 of the discharge tray section 60 is shown in FIG.
As described above, it extends from above the conveying unit 10 to above the separating and feeding unit 40, and the leading end portion thereof is the document tray unit 30.
It is supposed to overlap on top of. Therefore, in this state, the L-size original or the like having a particularly large size which is ejected vigorously from the paper ejecting section 50 may have its leading end hanging on the original tray section 30 as shown in FIG. 12 or dropping in some cases. Therefore, as described above, the discharge sub-tray 65b which can be projected and retracted in association with the document sub-tray 65a and the like is attached so that it can be pulled out when processing an L-size document. When placing an L-size original on the original tray 31, the original sub-tray 65a and the like must be pulled out without fail, and the paper ejection sub-tray, for example, 65b, is automatically pulled out in conjunction with it, so there is no forgetting to pull it out. ..

Since the paper discharge tray 61 is arranged in the upper half of the original tray 31, the original on the original tray 31 and the copied original are placed and stored above the platen P of the copying machine M in an overlapping state. To be done. As described above, the size and weight are small and there is no restriction on the installation area of the copying machine M.

Next, as shown in FIGS. 2 and 8, the platen cover portion 20 is provided below the separating / feeding portion 40 on the platen P side, and the platen cover 21 is arranged in parallel with the platen P.
And supporting members 22 and 23 for supporting the platen cover 21 at a predetermined distance from the platen P and detachably with respect to the automatic document feeder F, and elevating means 24 for moving the platen cover 21 close to and away from the platen P. It has and.

The platen cover 21 has an engagement fixing portion 211 for engaging and fixing the platen cover 21 with respect to the support member 22, and a platen cover 21 for engaging with the support member 23.
The slide portion 212 that slides the platen P in a direction substantially parallel to the platen P, and an operator can grip the support members 22 and 23 and the platen cover 21 in order to release the engagement and fixation, and the support member 23. More Platen Cover 2
A U-shaped weight portion 213, which is provided on the downstream side of No. 1 and has a relatively large weight, is provided.

The support member 23 is fixed to the frame of the automatic document feeder F. The support member 22 is connected to the drive shaft 242 by a connecting member 241.

The platen cover section 20 is an area on the upper surface of the platen P other than the area covered by the document conveying section 10, that is, approximately half (between Y and Z) on the opposite side of the reading reference point X of the reading section T. It has a size to cover.

Next, the drive system of the document conveying section 10 and the platen cover section 20 and a part of the drive system of the separating / feeding section 40 will be described.

The output shaft 86 of the drive motor M2 is provided with an interrupter 871 formed by forming slits on a disk at equal intervals, and a photo is generated in response to light passing through the slit of the rotating interrupter 871. A pulse generator 87 including a sensor S4 is provided.

The conveyor belt 13 forming the conveyor path R2 is
The power from the drive motor M2 is transmitted to the belt drive transmission means 85.
The drive pulley 11 is rotated via the shafts 0, 851, the shaft 852, and the gears G8, G9, G10, so that the drive pulley 11 is driven in the forward direction (document conveying direction) and the backward feeding direction.

Further, the driven pulley 12 of the conveyor belt 13
The transfer roller 54 provided above the
The driving force is directly transmitted from the surface of the sheet discharge belt 51, and the paper discharge belt 51 is driven in the document transport direction at the same peripheral speed as the transport belt 13.

A registration roller 451 is fixed to the shaft 852, and is driven in the document transport direction at the same rotational angular velocity as the transport belt 13 but at a peripheral speed slightly slower than that of the transport belt 13.

That is, the registration roller 451 constituting the sheet feeding means and the conveyor belt 13 as the conveying means are constructed so that the latter has a higher conveying speed than the former, and the details of the operation will be described later. It constitutes a separating means for separating the preceding original document and the next original document.

Registration roller 451 and drive side pulley 1
1, the discharge belt 51 is one drive source (drive motor M2)
And the registration rollers 451 rotate at different peripheral surface speeds so that the registration roller 451 can convey the conveyance path R2 and the discharge passage R3 at a speed faster than the original fed in the feeding path R1. The rotary drive system described above can be controlled based on the clock signal of the pulse generating means 87.

On the other hand, the shaft 852, which is the rotation shaft of the registration roller 451, is driven by gears G11 and G as shown in FIG.
It is transmitted to the drive shaft 242 via G12 and G13. The drive shaft 242 is gear-connected so as to rotate in the same direction as the pulley 11 that drives the conveyor belt 13, and slides the platen cover 21 in the same direction as the conveyance direction in which the conveyor belt 13 is reversed. When the transport belt 13 is driven in the forward direction (document transport direction), the platen cover 21 is held at the solid line position in FIG. 8, that is, the position close to the platen P by the forward rotation of the drive shaft 242. The platen cover 21 is provided by the torque limiter 853 incorporated in the shaft 852.
Is held at the solid line position in FIG. 8 with a constant force.

When the conveyor belt 13 is driven in the reverse feeding direction, the platen cover 21 is rotated by the reverse rotation of the drive shaft 242.
Is held at a position indicated by a chain line in FIG. 8, that is, a position separated from the platen P.

The separating means for separating the preceding document and the next-conveying document while superposing them, and further separating them, makes the peripheral speeds of the registration roller 451 of the paper feeding means and the conveyor belt 13 of the conveying means different from each other. In addition to the above configuration, in an embodiment, only the conveyor belt 13 which is the above-mentioned conveying means for performing the reverse feeding operation at a proper time and the discharging operation are executed,
It can also be configured by the paper discharge unit 50 that is the above-described paper discharge unit that does not rotate reversely with respect to the reverse feeding operation of the transport belt 13.

Further, a configuration example of the separating means is shown in FIGS.
Further explanation will be given by another embodiment shown by 7.

In the apparatus shown in FIG. 15, the separating means is basically composed of the conveying means and the paper discharging means as in the above, but in the apparatus 900 of this embodiment, the paper discharging section 910 is discharged. Along the paper path R3, there are an entrance roller 911, a pinch roller 912, a paper ejection first roller 913, a paper ejection second roller 914, and the like. And the transport unit 910
The pulley 903 and the first discharge roller 913 are connected to the second drive motor M2, and the second discharge roller 914 is connected to the third drive motor M3. The first paper discharge roller 913 is coupled only via the one-way clutch ow (one-way rotation restricting means) so that it rotates only in the document discharge direction and does not rotate in the reverse feed direction. With the structure of the separating means,
Even if the preceding original comes into contact with the first and second rollers 913 and 914 at the same time, the original discharging operation is continuously executed, and the original is formed by the sliding contact of the first discharging roller 913. Does not damage.

The apparatus 920 shown in FIG. 16 has almost the same configuration as that of FIG. 15, but prevents the preceding document from unnecessarily retreating when the preceding document is pulled by the next document to be separated. For this reason, the reverse feeding prevention means 931 such as mylar is provided in the paper discharge path R3.

It is needless to say that the above-mentioned reverse feeding prevention means 931 can be applied to the paper discharge path R3 of the paper discharge means 50 (see FIG. 2) of the automatic document feeder F already described.

Further, in the apparatus 900 having the configuration of FIG.
A torque limiter TL (torque limiting means) is provided between the drive motor M3 and the second sheet ejection roller, whereby the preceding document that is slidingly contacting the second sheet ejection roller and is being ejected is being fed backward. When the conveyance belt 902 pulls the next document to be conveyed to the conveyance path R2 side, the document is protected by a relatively small torque without a discharge operation.

Further, as in the apparatus 950 of FIG. 17, the belt roller 903 and the first discharge roller 91 of the discharge means 960.
3 and the discharge second roller 914 are respectively driven by separate drive motors M2 and M3, the discharge second roller is driven in the discharge direction, and the discharge first motor is driven in the reverse direction. The paper discharge first roller 91 in contact with the document to be sent
3 and the drive motor M3, a torque limiter TL is interposed to form a separating means.

According to the structure of the separating means, when the first sheet discharging roller comes into sliding contact with the preceding document being discharged,
Due to the action of the torque limiter TL, the reverse rotation of the first sheet ejection roller is stopped, and the original is prevented from being unnecessarily rubbed and damaged.

Further, as an improvement of the embodiment shown in FIG. 16, the third drive motor M for driving the second sheet discharge roller 914 is used.
3 may be omitted, and the structure may be such that it is rotatably supported or rotatable only in the paper discharge direction. In this case, as a condition, the state of the preceding document and the next document to be fed in the double-feeding state is such that at least the preceding document is nipped between the first paper ejection roller 913 and the second paper ejection roller 914 to convey the next document. The transport control is executed so that the switch pack is performed at a position where the rear end portion in the direction can be fed back by the transport belt 901. That is, the separating operation performed at the time of switchback is performed by the prevention means 931 blocking the preceding document when the next document is conveyed backward by the conveyor belt 901, but the preceding document tries to be conveyed backward. Be separated. Then, the preceding document that has been pulled off and waited at the paper ejection port may be ejected to the outside by the first paper ejection roller 913 during the operation of ejecting the next document to be fed. Further, in this case, the inlet roller 911 and the pinch roller 912 are not always necessary.

Further, as another embodiment, the discharge first roller 913 is freely rotated, the discharge second roller 914 is driven by the drive motor M3, and the preceding original is discharged and the next original is separated from the preceding original. In this state, a torque limiter is provided in the second paper discharge second roller 914 in order to smoothly perform the reverse paper feed when the rear end of the next document to be fed in the backward direction is nipped by the second paper discharge second roller 914. It may be a structure.

In the following, returning to the description of the present embodiment, the hinge portion 70 is a hinge 71 with a spring for supporting the automatic document feeder F on the upper surface of the copying machine M so as to be openable and closable, as shown in FIG.
It is composed of a hinge 72 without a spring.

Next, the operation will be described.

When the document D is set on the document tray 31 and a copy command is given to the copying machine M prior to copying, the presence of the document D is confirmed by the empty sensor S1 and the document stopper 46 is placed below the guide plate 411. The document tray 3 is retracted and descends while the pickup roller 42 rotates.
The original D on 1 is touched. As a result, the document D is sent forward, enters between the paper feed roller 43 and the separation belt 44, and the document D is advanced by the paper feed roller 43 rotating in the transport direction. At this time, the separation belt 44 which rotates in the reverse feeding direction prevents the lower original that contacts the separation belt 44 from advancing, and only one original is allowed to pass by the paper feed roller 43.

The document D sent in this way is contacted by the registration roller 451 and the pinch roller 452 in the stopped state after the leading edge thereof is detected by the registration sensor S2. After a lapse of a predetermined time from the detection of the leading edge of the document D, the rollers 42, 4
3. By stopping the belt 44, the document D is somewhat bent and the leading edge is uniformly pressed to the tangent portion of the registration roller 451 and the pinch roller 452, and the registration roller 451 and the pinch roller 451 which start to rotate after the document D contacts. The leading end of the roller 452 is drawn in parallel to the roller 452 and sent out.

The document D conveyed through the feeding path R1 as described above is guided to the entrance of the conveying path R2 at the substantially center (point Y) of the reading section T of the platen P. Thus, the conveyor belt 13
The document D, which has entered the entrance of the conveyance path R2 formed between the platen P and the platen P, is sent forward along the conveyance path R2 by the conveyance belt 13 which is slightly faster than the registration roller 451.

At this time, the length of the document D in the carrying direction is determined by counting the pulse signals from the pulse generating means 87 from the time when the drive motor M2 is activated until the trailing edge of the carried document passes the registration sensor S2. it can. That is, at least the registration roller 451 and the conveyor belt 13 that are involved in the conveyance of the document D are synchronized with the pulse of the pulse generation means 87 and maintain the same conveyance speed, so that from the start of the drive motor M2 to the reading reference point X. The number of pulses can be recognized in advance, and when the registration sensor S2 detects the trailing edge of the document D while the leading edge of the document D is on the way from the point Y to the point X, the conveyed document is at least at the point X-.
It can be seen that it is less than or equal to the length between Y. That is, in this case, the document is determined to be the S size document.

When the original is an S-size original, the conveyor belt 13 is stopped after the pulse generator 87 has counted a predetermined pulse (A pulse) after the rotation of the drive motor M2 is started. As a result, the document D can be stopped at the reading position in which the leading edge of the document is accurately aligned with the reference point X.

Next, it is judged whether or not the empty sensor S1 detects the original, and when the presence of the original D is not detected, the copying machine M is operated to execute copying. When copying is completed, the conveyor belt 13 and the paper discharge belt 51
Is operated to guide the document D to the paper discharge path R3, and the paper discharge tray 6
Discharge to 1.

When the empty sensor S1 detects a document, the drive motor M1 is started to drive the document tray 31.
Then, the next original document D is sent toward the registration roller 451 and the copying machine M is operated to perform copying.

When the copying is completed, the driving belt M13 is stopped after the pulse generation means 87 has counted a predetermined pulse (A pulse) from the start of the drive motor M2. At this time, the leading edge of the first (first sheet) original is discharged to the paper discharge tray 61 with the rear end thereof being restrained by the paper discharge unit 50.

When the empty sensor S1 detects the document D to be copied on the document tray 31, the above-described operation is appropriately repeated, and the copied documents D are sequentially accumulated on the paper discharge tray 61.

Next, a case of handling an L size original will be described with reference to FIGS. 13 and 14 (a) to (d).

From the start of the above-described document conveyance, the document D1 is moved forward along the conveyance path R2 between the conveyance means 13 and the platen P.

If the document D1 moving forward on the conveying path R2 passes the reading reference point X and the trailing edge of the document does not pass the registration sensor S2, the document D is judged to be an L size document. In this case, the conveyance of the document D1 is continued until the pulse generation means 87 counts a predetermined pulse (B pulse) after the trailing edge of the document passes the registration sensor S2.

When the trailing edge of the original reaches the entrance (point Y) of the conveying path R2, the leading edge of the original D1 is conveyed to the upper surface of the paper discharge tray 61 through the paper discharge section 50 as shown in FIG. 13C. ing. Next, the transport belt 13 is rotated in the reverse direction, and the document D is fed backward along the upper surface of the platen P. As a result, the document D
1 enters between the platen P and the platen cover 21 between points YZ of the reading section T.

The original D1 is fed backward by the conveyor belt 13 until the leading edge of the original passes the reference point X of the reading section T by a predetermined amount. The switchback sensor S3 is used for backward feeding of the document D1.
Is controlled based on the detection signal of the trailing edge of the document (leading edge during forward feeding; left edge in the figure). That is, after the trailing edge of the document to be fed back passes the switchback sensor S3, the conveyance belt 13 is fed backward until the pulse generating means 87 counts a predetermined pulse (C pulse), and the trailing edge of the document D1 is the reading section. The transport belt 13 is stopped at the point W at the point T. (See FIG. 13D.) When the document is fed backward by the conveyor belt 13, the drive system of the platen cover 21 described above is simultaneously driven, and the platen cover 21 moves in a direction away from the platen P. .. As a result, the document D1 can enter between the platen P and the platen cover 21 between the points YZ of the reading unit T.

After that, the document D1 is again transported in the forward direction by the transport belt 13, and the transport belt 13 is stopped when the rear end (left end) of the document D1 to be sequentially fed is located at the reference point X of the reading section T. .. That is, after the pulse generator 87 counts a predetermined pulse (D pulse) that is overrun from the reference point X in the backward feeding, the feeding of the feeding belt 13 in the forward feeding direction is stopped. (See FIG. 14A.) As described above, when the document D1 is conveyed by the D pulse by the forward rotation of the conveyance belt 13, the platen cover 21 moves in the direction approaching the platen P. By this, the point Y-Z of the reading section T
The document D1 that has entered between the platen P and the platen cover 21 in between is pressed down to the platen P side. Copying is performed there.

During the copying operation, when the document is not detected on the document tray 31 by the empty sensor S1, the conveying belt 13 and the paper discharge belt 51 are driven in the forward feeding direction to convey the document D.
1 is sent to the discharge tray 61 via the discharge path R3.

When the succeeding copy original D is detected by the empty sensor S1, the next original to be fed is advanced to the registration roller 451 as shown in FIG. 14A. Then, as shown in FIG. 14B, at the same time as the exposure is completed, the preceding original document D1 is also started to be conveyed together with the next original document D2 which has been previously fed to the registration roller 451.

When the conveyance is started, the linear velocity of the conveyance belt 13 is higher than the peripheral velocity of the registration roller 451, and at the same time, the preceding document D1 which is not restricted by the registration roller 451 while traveling along the conveyance path R2 is further advanced. Fast, both originals D
Documents D1 and D2 are gradually pulled apart, and the document D1 is quickly discharged from the paper discharge unit 50 to the paper discharge tray 61. (Fig. 1
4 (c), (d)).

On the other hand, the next original document D2 is switched back like the original document D1, is inserted under the platen cover 21, and is exposed.

While the preceding original document D1 and the next original document D2 are superposed on each other, the separating means for separating the original documents D1 and the next original document D2 are the conveying belt 13 which is the above-mentioned conveying means for performing the reverse feeding operation at appropriate time.
And a discharging unit 50 that is a discharging unit that performs only the discharging operation and does not rotate reversely with respect to the backward feeding operation of the conveyor belt 13.
In the case of the configuration constituted by, the conveyance belt 13
The discharging operation by is stopped, and only the next original document D2 that is in contact with the transport belt is separated and is fed backward.

The operation of the detaching means shown in FIGS. 15 to 17 showing various examples of the configuration has been described in the configuration description, and thus the description of the operation is omitted here.

When a large number of L-size originals are successively processed as described above, the next original to be fed is superposed on the spine of the preceding original or is advanced in the vicinity thereof, and the latter half of the exposed original is still below the platen cover 21. Since both originals are fed in parallel before being removed from the original, and both originals are separated during conveyance, the supply and replacement speeds of the originals to the image forming apparatus are significantly increased, and the number of sheets processed per hour is dramatically improved. You can

In the above embodiment, about twice the S size original is set as the L size original, but the L size (between X and Z) is set to be larger than twice the S size (between XY). Needless to say, it is also possible to make it smaller.

According to the automatic document feeder of the present invention, while the preceding document set on the platen is fed forward so that the leading edge of the next document is overlapped with the non-processing side of the preceding document, the preceding document is discharged. Since the next original is separated from the preceding original and the separating means is provided to set the next original on the platen, the distance between the original and the next original can be maintained at zero when exchanging originals, and the original original is replaced. There is no transport loss required at times, the document replacement process is quick, and the number of original documents processed per hour by the automatic document feeder can be significantly improved.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment in which an automatic document feeder of the present invention is applied to a copying machine.

FIG. 2 is a vertical sectional side view of the same automatic document feeder.

FIG. 3 is a plan view of the same automatic document feeder as above.

FIG. 4 is a plan view showing a drive system of a part of the separation feeding unit.

FIG. 5 is a plan view showing a drive system of part or all of a separation feeding unit, a document conveying unit, and a platen cover unit.

FIG. 6 is an explanatory view of a main part of a paper discharge unit.

FIG. 7 is a detailed structural diagram of a paper discharge section pulley.

FIG. 8 is a side view illustrating an outline of a platen cover part.

FIG. 9 is an example of an interlocking configuration of a document sub tray and a paper ejection sub tray.

FIG. 10 is another embodiment of the interlocking configuration of the original sub-tray and the paper output sub-tray

FIG. 11 is still another embodiment of the interlocking configuration of the original sub-tray and the paper output sub-tray.

FIG. 12 is an operation explanatory view of a device lacking a document sub tray and a paper discharge sub tray.

FIG. 13 is an explanatory diagram showing a feeding state of a large-sized document.

FIG. 14 is an explanatory diagram showing a feeding state of a large-sized document.

FIG. 15 is an embodiment showing the structure of the separating means.

FIG. 16 is another embodiment showing the structure of the separating means.

FIG. 17 is still another embodiment showing the structure of the separating means.

FIG. 18 is a perspective view showing a state where the automatic document feeder has released the platen.

FIG. 19 is an explanatory view showing a state in which the belt pulley is lifted and separated from the platen cover end portion.

FIG. 20 is an explanatory view of a state in which the belt pulley is lowered and brought into close contact with the end of the platen cover.

FIG. 21 is a structural explanatory view of a belt pulley vertical movement mechanism.

FIG. 22 is an explanatory view of main parts of a device lacking a belt pulley vertical movement mechanism.

[Explanation of symbols]

 F Automatic Document Feeder P Platen D Document 10 Document Feeder 40 Separation Feeder 50 Paper Ejector

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location G03G 15/04 119

Claims (7)

[Claims] 1. A feeding means for feeding a document and a feeding means for holding the fed document between a platen of an image forming apparatus for processing, feeding the document after processing, and receiving a document from the feeding means. In an automatic document feeder including a sheet discharging unit for discharging the sheet, the sheet feeding unit feeds the leading edge of the next sheet to the non-processing side of the preceding sheet on the platen in the sheet feeding direction. An automatic document feeder, comprising: a separation unit that separates a next document to be conveyed from a preceding document by an operation of discharging a processed document. 2. The separating means comprises the paper feeding means for feeding the original at a predetermined original feeding speed, and the conveying means for discharging at a discharging speed faster than the predetermined paper feeding speed of the paper feeding means. The automatic document feeder according to claim 1, wherein the automatic document feeder. 3. The separating means contacts the preceding document and discharges it, and the conveying means which contacts the next document and separates the next document from the preceding document by a switchback operation. The automatic document feeder according to claim 1, wherein the automatic document feeder is constituted by: 4. The paper discharging means is composed of a pair of paper discharging rollers, and a common drive source for driving the side of the paper discharging rollers which comes into contact with the next original and the conveying means is provided. The paper discharge roller on the side in contact with the next document to be fed is provided with a one-way rotation restricting means that rotates by the discharge direction operation of the drive source but does not rotate when driven in the switchback direction. 3. The automatic document feeder according to item 3. 5. The automatic document feeder according to claim 4, further comprising a reverse feeding prevention unit for preventing the backward feeding of the preceding document in the middle of the discharge path from the conveying unit to the discharge unit. Characteristic automatic document feeder. 6. The automatic document feeder according to claim 3, wherein the paper discharge unit is composed of a pair of paper discharge rollers, and the paper discharge roller on the side in contact with the preceding document and the conveying unit are separate from each other. While being driven by the drive source, the paper discharge roller on the side in contact with the preceding document stops its rotation due to the sliding friction force generated between the preceding document and the next document due to the switchback operation of the conveying means. An automatic document feeder, comprising: 7. The paper discharging means has a driving source separate from the conveying means and is composed of a pair of paper discharging rollers, and the driving source of the paper discharging roller discharges the side in contact with the preceding document. Direction, and the side in contact with the next document is driven to rotate in the opposite direction, and the rotation of the discharge roller on the side in contact with the next document is stopped when the roller simultaneously contacts the preceding document. 2. The automatic document feeder according to claim 1, further comprising a torque limiting unit for controlling the automatic document feeder.