JP2905950B2 - Document feeder for image forming apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a document feeder used for an image forming apparatus such as a copying machine.

2. Description of the Related Art In general, a document feeder used for an image forming apparatus having a substantially horizontal platen has a first
Supporting means, separating means for separating and sending the originals supported by the first supporting means one by one, first guiding means for guiding the originals sent from the separating means, Conveying means for conveying the document guided by the guide means to the reading position on the platen, and thereafter discharging the document; second guiding means for guiding the document sent from the conveying means; and second guiding means. Second supporting means for supporting the guided document.

However, conventionally, there has been a problem that the first support means and the second support means protrude greatly from the platen, and the apparatus becomes large.

Therefore, an apparatus which solves this problem and reduces the size of the apparatus is disclosed in Japanese Utility Model Laid-Open No. 63-142340. That is, in this publication, first supporting means for loading an original with an image facing upward is provided above a platen, and a first guide for inverting the original sent out from the first supporting means by a separating means is provided. Means is provided, followed by a transport means for transporting the document onto the platen, and thereafter discharging the document in a direction substantially opposite to the direction guided by the first guide means, and provided from the transport means. An apparatus in which a second guide for reversing a document is provided, and a second support for supporting the document with its image facing upward is provided below the first support and above the platen. Is disclosed.

[0004]

Problems to be Solved by the Invention
In the apparatus described in Japanese Patent No. 2340, the second support means is provided with the first support means.
On the underside of the support means. Therefore, there is a problem that the first support unit becomes an obstacle when the operator removes the image-processed document on the second support unit.

An object of the present invention is to provide a document feeder for an image forming apparatus in which the first support means does not hinder the removal of the image-processed document from the second support means.

[0006]

In order to achieve the above object, the present invention is directed to a first support means which is provided at least partially above a platen and stacks an original with an image to be processed facing downward. , Provided above the platen,
Separating means for separating and sending the originals supported by the supporting means one by one, and guiding the original sent from the separating means to the platen from a predetermined position on the platen with the image on the lower side provided above the platen First guiding means for
Transport means for covering the document from a predetermined position on the platen to one end of the platen, transporting the document guided by the first guide means to a reading position provided on one end side of the platen, and thereafter discharging the document from one end side; A second guide unit for guiding the document sent from the transport unit while reversing the document, and a second guide unit provided above the first support unit, the separation unit, and the first guide unit, and guided by the second guide unit. Second supporting means for supporting the document with the image facing upward.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention can be applied to a copying machine, various printers, facsimile machines, etc., but an example of a document feeder applied to a copying machine will be described with reference to the accompanying drawings. A document feeder F is placed and mounted above the copying machine M shown in FIG. The external shape of the document transport device F is substantially square, so that the document transport device F does not protrude greatly on both left and right sides when viewed from the front of the copying machine M.

A platen P is provided in an upper portion of the copying machine M. A document conveying device F placed so as to cover the platen P covers a certain area corresponding to substantially half of the platen P. The transport unit 10, a platen cover unit 20 that also covers the remaining area of the platen P, and a document set on the document tray unit 30 provided above the platen cover unit 20 and separated and fed toward the platen P. A separating / feeding unit 40; a paper discharge unit 50 that receives the exposed document conveyed by the conveyance unit 10 and discharges it from the platen P; and a storage unit 6 that stores the document discharged by the paper discharge unit 50
0, a hinge 70 for supporting the document feeder F so as to be able to open and close above the platen P of the copying machine M;
And a control unit 80.

FIG. 20 shows a state in which the document feeder F in FIG. 1 is released above the platen P, and an effective reading range (reading section T: length X-Z) is defined on the upper surface of the transparent platen P. And one end of the reading unit is determined as a reading reference point X. At the time of copying, a copy corresponding to the original is obtained by arranging one end of the original D with the reference point X.

The reading unit T has a maximum size that can be copied, and is indicated by a dashed line in the figure. For example, an A3 size (297 mm × 420 mm) is set as the maximum size that can be copied. Here, an A3 size is set as a large size, and an A4 size (210 mm × 29 mm) is set.
7mm) is assumed to be a small size. Therefore, the entire length (between X and Z) of the reading unit T is for a large-size document, and half (X-
(Between Y) is for small-size originals. In FIG. 20, a small-size document D is positioned on the reading unit T in accordance with the reference point.

FIG. 2 shows two drive motors M1 and M2 provided in the document feeder F and sensors S1 to S2 for collecting information necessary for controlling the operation of the document feeder F.
5, and a control board 89 are shown.

The drive motor M1 is drivingly connected to the separation feeding section 40, and is driven and controlled mainly based on output signals from the sensors S1 and S5.

The drive motor M2 is drivingly connected to the transport unit 10 and is driven and controlled mainly based on output signals from the sensors S2, S3 and S4.

The sensor S1 is an empty sensor for detecting the presence or absence of a document set on the document tray 30.

The sensor S2 is provided in the middle of a transport path for transporting the original separated by the separation / feed unit 40 to the platen P, and detects a leading end or a trailing end of the original passing through the transport path. It is a sensor.

The sensor S3 is a switchback sensor for detecting the leading edge or the trailing edge of the document conveyed through the paper discharge unit 50.

The sensor S4 is connected to the output shaft 8 of the drive motor M2.
6 is a photosensor that detects the amount of rotation of an interrupter 871 (described later) provided in 6.

The sensor S5 is provided on the hinge portion 70, and the original conveying device F sends the platen P to the copying machine M.
It is detected whether it is in an open state in which the upper part is open or in a closed state in which the upper part of the platen P is closed as shown in FIG.

Further, the storage section 60 is provided with a projection member 62 extending in a direction substantially parallel to the document transport direction. The protruding member 62 is provided to allow the original stored in the storage unit 60 to be rigid. When the stored original is longer than the storage unit 60, the leading end thereof protrudes from the storage unit 60, and the leading end of the protruding original. Is prevented from hanging down on the document tray section 30.

Next, a detailed description will be given of the document feeder F with reference to FIGS.

As shown in FIG. 3 and FIG.
The document tray unit 30 as a first supporting means for loading a document with an image to be processed on a lower side from an upstream (right side in FIG. 3) to a downstream side (left side in FIG. 3) in the document conveying direction.
And a separating / feeding unit 40 serving as separating means for separating and transporting the document on the tray into one sheet, and a transporting means for receiving the document transported by the separating / feeding unit 40 and transporting the document further downstream. Is provided.

A platen cover section 20 is provided below the separating and feeding section 40 on the platen P side, and a document received from the document conveying section 10 is positioned above and downstream of the document conveying section 10. Paper output unit 5 that transports paper while turning it over
0 is provided. Above the separation feeding section 40 and the document transport section 10, a storage section 60 as a second support means for storing the document transported by the paper discharge section 50 is provided.

In the document feeder F, the document tray 3
Reference numeral 0 denotes a loading tray 31 and a pair of side end guides 32L, which regulate side edges of the document set on the loading tray 31,
32R and an auxiliary tray 33.

The side end guides 32L and 32R extend in the width direction of the original along the guide 321 (vertical direction in FIG. 4).
Go to A rack and pinion mechanism (not shown) is connected to the side end guides 32L and 32R, and positions the center of the document set on the loading tray 31 at the reference line K shown in FIG.

The auxiliary tray 33 is attached to the loading tray 31 so as to be rotatable by a rotation shaft 331, and stably supports the rear end of a large-size document placed on the loading tray 31.

The separation / feeding section 40 guides an image to be processed on a separated original sheet from a predetermined position of the platen P (the center Y point of the reading section T in this example) onto the platen P with the image to be processed facing downward. A document transport path R1 is formed as a first guide unit to be operated, and the document transport path R1 is partitioned by guide plates 410 and 411. Separating means for separating and sending the documents set on the tray 31 described above one by one is arranged along the document transport path R1. That is, the pickup roller 42 is provided on the entrance side of the transport path R1 so as to be able to advance and retreat to the loading tray 31, and the paper feed roller 43 and the separation belt 44 enter the transport path R1 from the respective guide plates 410 and 411 and are not in contact with each other. In this state, they are arranged so as to overlap each other. A registration roller 451 and a pinch roller 452 are provided on the exit side of the transport path R1 so as to face each other.

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

At the entrance of the conveyance path R1, a document stopper 46 provided to be able to advance and retreat with respect to the guide plate 411, and the presence or absence of a document on the loading tray 31 in cooperation with the sensor S1 (see FIG. 2). Is provided, and a sensor S2 is provided between the feed roller 43 and the registration roller 451 on the transport path R1. The document stopper 46, the pickup roller 42, the paper feed roller 43, and the separation belt 44 provided along the transport path R1
As shown in FIG. 0, the power from the motor M1 is rotated in a predetermined direction via belt drive transmission means 810, 811 and a plurality of gears G.
It is configured to rotate.

Here, it is assumed that one document is pulled out from the loading tray 31 and sent to the transport path R1.
The first rotation (forward rotation) is transmitted to the shaft 831 via the gears G2, G3, G4, and the rotation of the shaft 831 drives the drive transmission member 832 to rotate the shaft 833 in a predetermined direction.

At this time, the document stopper 46 moves to the position shown by the chain line in FIG. 3, so that the document on the loading tray 31 can be separated and fed. When the document stopper 46 rotates (down) and hits a stopper (not shown), the spring 834 prevents the shaft 833 of the document stopper 46 from being driven with a driving force exceeding a certain level.

The pickup roller 42 is connected to a shaft 82 for holding the sheet feed roller 43 by a swing arm member 821.
The swing arm member 821 is fixed to the shaft 831 and is rotated downward toward the document by rotation of the lever 836 which is in contact with the swing arm member 821. Contact the surface. When the pickup roller 42 comes into contact with the document, the spring clutch 834 keeps the contact pressure of the pickup roller 42 against the document constant.

Further, the forward rotation of the motor M1 corresponds to the gears G1, G5, G
6, G7 and transmitted to the shafts 82 and 84,
And the separation belt 44 are rotated in directions different from each other.

The one-way clutch 822 is incorporated in the gear G7, and even if the rotation of the gear G7 is stopped, if the document is forcibly conveyed forward, the paper feed roller 43 is moved forward. It follows and rotates.

The one-way clutch 823 is also incorporated in the gear G6, so that even if the rotation of the gear G5 is stopped, if the document is forcibly conveyed forward, the separation belt 44 follows the advance of the document. To rotate.

A one-way clutch 824 is built in the gear G1. When the motor M1 rotates in the reverse direction, the gear G1 idles and does not transmit the drive to the rollers 42, 43 and the separation belt 44. The drive is transmitted to the motor 836, and the motor M1 is rotationally driven in a direction opposite to that when the motor M1 rotates forward.

The shaft 838 is provided with a spring clutch 837. When the motor M1 rotates in the reverse direction, the original stopper 4
6 and the lever 836 are prevented from being driven upward by a force greater than a predetermined value.

According to the configuration of the separation sheet feeding section 40 described above,
When the motor M1 rotates forward, only the pickup roller 42 and the paper feed roller 43 rotate in the forward direction (document conveying direction),
The separation belt 44 rotates in the reverse feeding direction. Thereby, the documents placed on the loading tray 31 are transported one by one from the entrance to the exit of the transport path R1.

When the motor M1 rotates in the reverse direction, the lever 836
Rotates the pickup roller 42 away from the surface of the document.

The document conveying section 10 includes an endless belt-shaped conveying belt 13, a pair of pulleys 11 and 12 for driving the conveying belt 13 so that the conveying belt 13 can be rotated forward and backward, and a plurality of press rollers 14 for pressing the conveying belt 13 against a platen P. Become. Further, the document transport unit 10 is provided with approximately half (X
−Y).

At the exit of the transport path R1, a transport belt 13 is provided. The conveyance belt 13 forms a document path R2 with the platen P, and the entrance of the document path R2 is located substantially at the center (point Y) of the reading section T, and the exit is set at the front end of the reading section T. It is located approximately at the reference point X.

The document conveyed by the document conveyer 10 conveys the document discharged from the exit of the conveyance path R1 to the reference point X of the reading unit T, or conveys the paper forward from the reference point X and discharges it. Can be transported in the opposite direction.

As shown in FIGS.
At the rear of the exit (reference point X), there is provided a paper discharge unit 50 connected to the document transport unit 10. The paper discharge unit 50
An endless belt-shaped paper discharge belt 51, a pair of pulleys 52 and 53 for driving the paper discharge belt 51 to be able to rotate forward and backward, and a rolling roller 5 for transmitting the drive of the transport belt 13 to the pulley 53.
4 and a document discharged from the exit of the document path R2.
Guide members 55 and 56 for guiding the
A discharge path R3 is formed as second guide means for guiding the document sent from the transport belt 13 between 5 and 56 while reversing the document.

A leaf spring member 57 having one end fixed to the guide member 55 and pressing the original against the discharge belt 51 at the other end is provided at a position where the discharge belt 51 has escaped from the facing portion.

The transfer roller 54 is urged by a spring member (not shown) directly on the surface of the conveyor belt 13 at a position facing the driven pulley 12, and is connected to the fourth and seventh rollers.
As shown in the figure, the contact is substantially at the center of the conveyor belt 13.

The discharge belt 51 and a pair of pulleys 5
Since the rollers 2 and 53 and the transfer roller 54 are integrally supported by a pair of left and right side plates 58 and can be fixed as a unit to the outer cover of the transport device F, the assembly is easy.

In this embodiment, the document discharged from the document path R2 between the transport belt 13 and the platen P is introduced into the paper discharge path R3 and transported to the storage unit 60.

The storage section 60 comprises a storage tray 61 as a second support means, and a projecting member 62 extending in a direction substantially parallel to the document conveying direction. Since the storage tray 61 is disposed above the loading tray 31, the copying machine F is placed in a state where the document D separated and fed and the copied document D1 overlap as shown in FIG.
Is placed and stored above the platen. In other words, it is possible to configure a document conveying device that is small and light, has no particular restriction on the size of the document to be conveyed, and can easily handle the processed document.

Referring to FIGS. 3, 8, and 9, the platen cover 20 is provided below the platen P side of the separation / feeding unit 40, and is opposed to the platen P in parallel with the platen P. Support members 22 and 23 for supporting the cover 21 at a predetermined distance from the platen P and detachably with respect to the document feeder F;
And an elevating means 24 for bringing the platen close to and away from the platen P.

The platen cover 21 has an engagement fixing portion for engaging and fixing the platen cover 21 to the support member 22.
211, a slide portion 212 that engages with the support member 23 to slide the platen cover 21 in a direction substantially parallel to the platen P, and releases the engagement and fixation between the support members 22, 23 and the platen cover 21. For this purpose, a U-shaped weight portion 213 which can be gripped by an operator and is provided downstream of the support member 23 in the sliding direction of the platen cover 21 and has a relatively large weight is provided.

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

FIG. 9 shows a state in which the platen cover 21 is
2 shows a state in which it is detached from 2, 23. Although the drawing shows a state in which the document feeder F closes (covers) the platen P of the copying machine M, normally, when the platen cover 21 is removed, the document feeder F is placed above the platen P. The maintenance of the separation belt 44 and other mechanisms provided in the separation feeding section 40 can be easily performed.

The platen cover section 20 is located on the upper surface of the platen P except for the area covered by the original transport section 10, that is, substantially half of the reading section T on the opposite side to the reading reference point X (between YZ). It has a size to cover.

With reference to FIGS.
0, drive system of platen cover section 20 and separation feeding section 40
A part of the drive system will be described.

An output shaft 86 of the motor M2 is provided with an interrupter 871 in which slits are formed on a disk at equal intervals, and a photosensor that generates a pulse in response to light passing through the slit of the rotating interrupter 871 A pulse generating means 87 made of S2 is provided.

The conveyance belt 13 forming the document path R2 receives power from the motor M2 by belt drive transmission means 850 and 851,
52, the drive pulley 11 is rotated via the gears G8, G9, G10 so as to be driven in the forward direction (document conveying direction) and the reverse direction.

The driven pulley 12 of the conveyor belt 13
Roller 54 provided above the conveyor belt 13
The drive is transmitted directly from the surface of the paper feed belt 51, and the discharge belt 51 is driven at the same peripheral speed as the transport belt 13 in the same document transport direction.

A registration roller 451 is fixed to the shaft 852, and is driven at the same peripheral speed as the conveyor belt 13 in the same document conveyance direction.

That is, the registration roller 451, the driving pulley 11, and the discharge belt 51 are one driving source (motor M2).
, And rotate while maintaining substantially the same peripheral surface speed so that the document roller R2 and the paper discharge path R3 can be conveyed at the same speed as the document sent along the conveyance path R1 by the registration roller 451. That is,
Originals conveyed in passages R1, R2, and R3, regardless of the order,
It moves at a constant speed. The above-described rotary drive system can be controlled based on the clock signal of the pulse generating means 87. On the other hand, shaft 852 is driven by gears G11, G
It is transmitted to the drive shaft 242 via 12, G13. The drive shaft 242 is
Gears are connected so as to rotate in the same direction as the pulley 11 that drives the transport belt 13, and slide the platen cover 21 in the same direction as the reverse transport direction of the transport belt 13. When the transport belt 13 is driven in the forward direction (document transport direction), the forward rotation of the drive shaft 242 holds the platen cover 21 at the position indicated by the solid line in FIG. Torque limiter 8 built into shaft 852
By means of 53, the platen cover 21 is held at a constant position in the solid line position in FIG.

When the transport belt 13 is driven in the reverse feeding direction, the platen cover 21 is held at the position shown by the chain line in FIG. The platen cover 21 is held by the torque limiter 854 incorporated in the shaft 242 with a constant force at the position indicated by the chain line in FIG.

The hinge 70 shown in FIGS.
Is composed of a hinge 71 with a spring for supporting the document feeder F on the upper surface of the copying machine M so as to be openable and closable, and a hinge 72 without a spring.

The hinge 71 with spring includes a main body fixing portion 711 fixed to the copying machine M side, an attached fixing portion 712 fixed to the conveying device F side, a pin 713 connecting the both portions 711 and 712, and both portions 7
Spring means 7 for urging 11,712 in the opening direction about pin 713
It consists of fourteen.

Further, it is provided at a position slightly upstream (right side in FIG. 4) of the document transport apparatus F with respect to the document transport direction (left-right direction in FIG. 4) from the center of the apparatus F with respect to the document transport direction. The hinge position is determined by the positions of the motors M1 and M2 and the motors M1 and M2.
The position of the center of gravity shifted to the upstream side in the transport direction of the apparatus F from the position of the rotary drive system or the like connected to the position 2.

The spring-free hinge 72 includes a support member 721 fixed to the copying machine M side, a concave support portion 722 provided on the document feeder F, and a pin 723 connecting the members 721 and 722.
The hinge 72 is provided at a position downstream (the left side in FIG. 4) of the document transport device F in the document transport direction. The support member 721 fixed to the copying machine M and the concave support portion 722 of the frame cover of the document transport device F are provided. It is rotatably connected by a pin 723.

The operation of the document feeder F having the above configuration will be described below.

FIGS. 12, 13 (A) to 13 (C) show a case where a relatively small size original such as A4 to letter size is handled.

FIG. 12A shows a state in which the original D is set on the placing tray 31 prior to copying. When a copy instruction is given to the copying machine M, the existence of the original D is confirmed by the empty sensor S1. The document stopper 46 is the guide plate 41
1, and the pickup roller 42 descends while rotating and contacts the original D on the loading tray 31. As a result, the document D is sent forward, and the paper feed rollers 43
The document D advances between the paper feed roller 43 and the paper feed roller 43 that rotates in the transport direction. At this time,
When a plurality of originals D are placed on the loading tray 31 as shown in FIG. 12B and a plurality of originals are simultaneously sent out by the pickup roller 42, the separation belt 44 rotating in the reverse feed direction causes the separation belt 44 to rotate. The lower document in contact with 44 is prevented from advancing. Therefore, only one document is allowed to pass forward by the feed roller 43.

After the leading edge of the sent original D is detected by the registration sensor S2, the original D contacts the stopped registration roller 451 and pinch roller 452. Manuscript D
By stopping the rollers 42 and 43 and the belt 44 after a predetermined time has passed from the detection of the leading edge of the document D, the original D bends somewhat, and the leading edge of the original D is uniformly adjusted by the registration roller 451 and the pinch roller 452
Is pressed against the tangent part of. As a result, the registration roller 451 and the pinch roller which start rotating after the original D contacts
It is pulled in with the tip parallel to 452 and sent out forward. (Skew correction operation) As described above, the conveyance path R1
Is guided to the entrance of the document path R2 substantially at the center (Y point) of the reading section T of the platen P. The document D that has thus entered the entrance of the document path R2 formed between the transport belt 13 and the platen P is sent forward on the document path R2 by the transport belt 13 driven in synchronization with the registration roller 451.

At this time, the length of the document D in the transport direction can be determined by counting the pulse signals from the pulse generating means 87 from the start of the motor M2 to the rear end of the transported document passing through the registration sensor S2. . That is, at least the registration rollers 45 involved in transporting the document D
Since the transport belt 13 maintains the same transport speed in synchronization with the pulse of the pulse generating means 87, the motor M2
The number of pulses from the start of the scanning to the point of reaching the reading reference point X can be recognized in advance, and the registration sensor S2 detects the trailing edge of the document D when the leading edge of the document D is on the way from the point Y to the point X. Then, it is found that the conveyed document is at least the length between the points X and Y. That is, in this case, it is determined that the document is of a small size. (See FIG. 16) As shown in FIG.
After the pulse generator 87 counts a predetermined pulse (A pulse) from the start of the rotation of 2, the transport belt 13 is stopped. Thereby, the document D can be stopped at the reading position where the leading edge of the document D is accurately aligned with the reference point X, as shown in FIG.

Next, it is determined whether or not the empty sensor S1 detects a document. If the presence of the document D is not detected, the copying machine M is operated to perform copying. When copying is completed, the transport belt 13 and the discharge belt 51 are operated to guide the document D to the discharge path R3 and discharge it to the storage tray 61.

When the empty sensor S1 detects a document, the motor M1 is started to send the next document D from the loading tray 31 toward the registration roller 451, and the copying machine M is operated to copy. Execute. (FIG. 13
(Refer to (A).) When copying is completed, the conveyance belt 13 is stopped after the pulse generation means 87 counts a predetermined pulse (A pulse) from the start of the motor M2. At this time, the leading end of the first (first) original document is discharged to the storage tray 61 with the rear end restricted by the discharge unit 50. (Figure 1
3 (B)) The loading tray 31 is detected by the empty sensor S1.
When the original D to be copied is detected, the above operation is repeated as appropriate, and the copied originals D are sequentially accumulated on the storage tray 61 as shown in FIG.

FIGS. 14 and 15 (A) to (D) show a case of handling a large-sized original longer than the distance between X and Y on the platen P defining a relatively small-sized area.

Start of conveyance of the above-mentioned document (FIG. 12A)
Then, the document D is advanced in the document path R2 between the transport means 13 and the platen P.

As shown in FIGS. 16 and 18, if the document D which advances along the document path R2 passes the reading reference point X but the trailing edge of the document does not pass the registration sensor S2, the document D is determined to be large. . In this case, the trailing edge of the original is
2, the pulse generation means 87 outputs a predetermined pulse (B
The conveyance of the document D is continued until the number of pulses is counted.

When the trailing edge of the document reaches the entrance (point Y) of the document path R2, the leading edge of the document D passes through the paper discharge unit 50 and is conveyed to the upper surface of the storage tray 61 as shown in FIG. I have. 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 is placed between the platen P and the platen cover 2 between the points YZ of the reading unit T.
Enter between 1.

The document D is conveyed backward by the transport belt 13 until the leading edge of the document passes the reference point A of the reading section T by a predetermined amount. The reverse feeding of the document D is controlled based on the switchback sensor S3 based on the detection signal of the rear end (the front edge during forward feeding; left side in the figure) of the document. That is, after the trailing edge of the document to be reversely fed passes through the switchback sensor S3, the transport belt 13 is transported backward until the pulse generating means 87 counts a predetermined pulse (C pulse). At the point W, the conveyor belt 13 is stopped. (Figure 1
4 (D)) from when the trailing edge of the document (the trailing edge during forward feeding; right side in the figure) passes through the registration sensor S2 until the pulse generating means 87 counts a predetermined pulse (B pulse), the transport belt 13 keeps the document. D is transported so that the leading edge of the document is always detected by the switchback sensor S3.
The switchback sensor S3 is disposed near the downstream side of the platen P in the forward direction in consideration of the size of the document to be used.

When the original is conveyed backward by the conveyor belt 13, the driving 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. This makes it easier for the document D to enter between the platen P and the platen cover 21 between the points YZ of the reading unit T.

Then, the original D is transported again by the transport belt 13 in the forward direction, and the rear end of the original D to be fed forward is read by the reading unit T.
At the reference point X, the transport belt 13 is stopped. That is, after the predetermined pulse (D pulse) overrun from the reference point X in the reverse feed is counted by the pulse generator 87, the transport of the transport belt 13 in the forward feed direction is stopped. (See FIG. 15 (A)) As described above, the conveyor belt 1
The platen cover 21 moves in the direction approaching the platen P when the document D is conveyed by the D pulse in the forward rotation of 3. As a result, the document D that has entered between the platen P between the points YZ of the reading unit T and the platen cover 21 is pressed down on the platen P side. Then, copying is performed.

After copying is completed, if the original is not detected on the loading tray 31 by the empty sensor S1, the transport belt 13 and the discharge belt 51 are driven in the forward direction to store the document D through the discharge path R3. It is sent to the tray 61.

When the subsequent copy original D is detected by the empty sensor S1, as shown in FIG. 15B, the motor M2 is driven by a predetermined pulse (E pulse) according to the size of the original to be copied. The rear end of the document (the rear end during the forward feeding) is conveyed to the substantially central portion (point Y) of the reading unit T by the forward feeding of the discharge belt 13.

Next, the next original is conveyed to the position of the registration roller 451 by the above-described original separating and feeding operation.
(FIG. 15C) Here, the motor M2 is activated to simultaneously rotate the registration roller 451, the transport belt 13, and the paper discharge belt 51. As a result, the copied document D1 is sent out to the storage tray 61, and the subsequent document D2
Moves forward on the transport path R1 toward the point Y of the reading section T, and the document D is sequentially fed by the transport belt 13 until the rear end of the document is located at the point Y of the reading section T as described above. (FIG. 15
(D)) According to the document feeder F having the above-described configuration, a relatively small-sized document transfer system having a relatively small size of about half (the size between X and Y) of the reading unit T on the platen P or less has a large size document ( (Size between X and Z) can also be carried out effectively, and the system can be streamlined, and the cost and size and weight of the apparatus can be reduced.

In the above embodiment, approximately twice the small size is set as the large size. Needless to say, even if the large size (between X and Z) is larger than twice the small size (between X and Y), Alternatively, it is practically possible to reduce the size.

[0082]

According to the present invention described above, in a document feeder for an image forming apparatus having a substantially horizontal platen, at least a part is provided above the platen, and a document to be processed is directed downward. A first supporting unit to be stacked, a separating unit provided above the platen and separating the originals supported by the first supporting unit one by one and sending out the original, and an original provided above the platen and sent out from the separating unit. Guide means for guiding the platen from a predetermined position on the platen to the platen with the image on the lower side, and covering the document from a predetermined position on the platen to one end of the platen and guiding the document guided by the first guide means on the platen A transport unit that transports the document to a reading position provided on one end side and then discharges the original from one end side; and a second guide hand that guides the original sent from the transport unit while reversing the original. And a second supporting means provided above the first supporting means, the separating means, and the first guiding means, and supporting the document guided by the second guiding means with the image facing upward. .

Therefore, since the second supporting means is located above the first supporting means, the first supporting means may be an obstacle when the operator removes the image-processed document from the second supporting means. Operability can be improved.

[Brief description of the drawings]

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

FIG. 2 is a perspective view showing an embodiment showing a partial internal structure of the document feeder according to the embodiment;

FIG. 3 is a side cross-sectional view of the document conveyance device;

FIG. 4 is a plan view of the document feeder according to the first embodiment;

FIG. 5 is a plan view showing a part of the drive system of the separation supply unit.

FIG. 6 is a plan view showing a part or all of a drive system of a separation supply unit, a document conveyance unit, and a platen cover unit.

FIG. 7 is a perspective view illustrating a main configuration of a paper discharge unit.

FIG. 8 is a side view schematically illustrating a platen cover section.

FIG. 9 is a side view for explaining the outline of attaching and detaching the platen cover.

FIG. 10 is a side view showing a part of the drive system of the separation supply unit.

FIG. 11 is a side view showing a part or all of a drive system of a separation supply unit, a document conveyance unit, and a platen cover unit.

FIG. 12 is an explanatory diagram illustrating a feeding state of a small-size document.

FIG. 13 is an explanatory diagram illustrating a feeding state of a small-size document.

FIG. 14 is an explanatory diagram illustrating a feeding state of a large-size document.

FIG. 15 is an explanatory diagram illustrating a feeding state of a large-size document.

FIG. 16 is a flowchart illustrating the separation / conveyance operation of the document conveyance device.

FIG. 17 is a flowchart illustrating the operation of conveying and discharging a small-size document.

FIG. 18 is a flowchart illustrating the operation of conveying and discharging a large-size document.

FIG. 19 is a side view for explaining an outline of a hinge portion.

FIG. 20 is a perspective view showing an embodiment in which the document feeder according to the present invention is applied to a copying machine with a platen released.

[Explanation of symbols]

 M Copier (Image Forming Apparatus) F Document Conveyor P Platen D Document 10 Document Conveyor (Conveyor) 20 Platen Cover 30 Document Tray (First Support) 40 Separation Feeder (Separator) 50 Discharge Paper section 60 Storage section (second support means) 62 Projecting member 70 Hinge section R1 Conveyance path (first guide means) R3 discharge path (second guide means)

Claims (2)

(57) [Claims] 1. A document feeder for an image forming apparatus having a substantially horizontal platen, wherein at least a part is provided above the platen, and first supporting means for loading a document with an image to be processed facing downward. Separating means provided above the platen, for separating and sending the documents supported by the first support means one by one; and providing the document sent from the separating means provided above the platen as the image. A first guide means for guiding the platen from a predetermined position on the platen with the lower side of the platen; a platen covering the platen from a predetermined position on the platen to one end of the platen, and guiding the document guided by the first guide means to the platen A transport unit that transports the original to a reading position provided on one upper end thereof, and then discharges the original from the one end, and guides the original sent out from the transport unit while reversing the original. And a second support provided above the first supporting means, the separating means and the first guiding means, and supporting the document guided by the second guiding means with the image facing upward. And a document feeder for an image forming apparatus. 2. The document guide according to claim 1, wherein a length of the second support means in the document guide direction is shorter than a maximum document, and an end of the second support means and a document end mounted on the first support means. Have an overlap in the vertical direction of the platen, and a projection member for preventing a document from hanging down from an end of the second support means is provided on the second support means. Item 2. A document feeder for an image forming apparatus according to Item 1.