JP2709966B2 - Automatic document feeder - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to an improvement of an automatic document feeder in a recording apparatus such as an electrophotographic copying machine.

[Background of the Invention]

An automatic document feeder (referred to as W or FADF) is generally used by being mounted on a platen glass (platen glass) of an image exposure unit such as a copying machine. In an optical system movable copier equipped with this automatic document feeder, the automatic document feeder feeds out one sheet at a time from a document table (stack section) on which a sheet-like document (hereinafter simply referred to as a document) is placed. The original is fed onto a platen glass by a conveyor belt, where it is exposed by an exposure unit lamp in the copying machine main body.
The document is further carried out onto a document discharge table.

The operation of exchanging the original on the platen glass by such an automatic original feeder has conventionally required a long time for exchanging the original, and thus has required a long copy processing time and reduced copy productivity. For this reason, it is required that the document be conveyed and stopped at a higher speed and more reliably.

[Problems to be solved by the invention]

When using the automatic document feeder to exchange documents within the return time of the scanning optical system during the document exchange operation in which documents are automatically fed and ejected onto the platen, copy productivity will be 10%.
It is 0% and no wasted time is required.

For this purpose, it is necessary to increase the document conveyance speed from the document double feed prevention position of the stack portion to the document stop position on the platen glass surface.

However, if the document is transported at a high speed and at a constant transport speed, it becomes uncertain that the document always stops at a predetermined position due to friction between the document and the platen glass. Therefore, even if the document is stopped by the stopper, the leading edge of the document is damaged due to high speed, and a jam or the like is caused.

[Means for solving the problem]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-described problem in the automatic document feeder and to improve the number of copies to be processed.

In order to achieve the above object, the automatic document feeder of the present invention sequentially transports a plurality of sheet-like documents to an image exposing unit by document conveying means including a document conveying belt, and provides the document at one end of the image exposing unit. The retractable document stopper is protruded and stopped at a predetermined position, the optical system is moved to perform scanning exposure, and after the exposure, the document is discharged to a document discharge table. The document is conveyed to the image exposing unit at the main document conveying speed, and when approaching a document stopper for stopping at a predetermined position of the image exposing unit, the original document main convey speed is determined by the inertial motion of the document conveying unit, and Control means for stopping the driving force of the document conveying belt so that the document is pressed against the document stopper at a speed at which the document stops beyond the document stopper position, and control means for projecting the document stopper It is characterized in.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a configuration diagram showing a document conveyance path of the automatic document conveyance device according to the present invention, FIG. 2 is a configuration diagram showing a drive system (power transmission system) of the automatic document conveyance device, and FIG. FIG. 4 is a perspective view showing a transport system and a drive system, and FIG. 4 is a plan view of a waist portion of the automatic document feeder. FIG. 5 is an external perspective view of the upper part of the copying machine equipped with the automatic document feeder. FIG. 6A is a schematic diagram showing a document transport path. The illustrated devices are automatic document feeders (RADF) with an automatic document reversing function.

First, the structure and operation of the automatic document feeder will be described with reference to FIGS. 1, 3, 5, and 6A.

A document placing table 1 is provided on the upper left side of the automatic document feeder so that documents can be stacked and placed. A document setting solenoid SD1 and a document leading end stopper 1 swingable by the solenoid SD1 are provided below the leading end of the document placing table 1.
D is provided. With the upper end of the leading end stopper 1D protruding near the leading end of the original placing table 1, the original bundle is placed on the original placing table 1, and the leading end of the original bundle abuts against the original leading end stopper 1D. Align the paper.

When the stack of originals is placed on the original mounting table 1, the presence or absence of the originals on the original mounting table is detected by the original set detection sensor (zero original detection sensor) PS2, and the control panel 110 of the copier body 100 displays the ADF mode. Is displayed.

On the document mounting table 1, there are provided width regulating plates 1A, 1A for regulating the width direction of the document. The horizontal width regulating plate 1A is provided on the lower surface of the document table 1 with a pinion gear.
The rack gears 1C, 1C, which can alternately slide sideways across the 1B, are connected to each other, and are symmetrically movable about the center. The rack gears 1C, 1C are connected to the width regulating plates 1A, 1A, respectively, and the amount of movement is detected by the document size detection sensor PS1, so that the width of the document can be read. The length of the document D of the standard size is automatically converted based on the read value. Therefore, by placing the original bundle on the original placing table 1 and sliding the lateral width regulating plates 1A, 1A to abut on the lateral width of the original, various original sizes, that is, each original length can be stored. Has become.

Above the vicinity of the leading end of the document table 1, the pickup roller 2 is vertically movable by the operation of a paper feeding solenoid (latch type) SD2 and spring pressure, and is rotatable by the driving force of a driving motor M. Has become. By operating the copy button 111 of the control panel 110, the automatic document feeder is activated, and the feed solenoid SD2 is energized and activated. The document is pressed against the upper surface, and at the same time, starts to rotate by the driving force of the driving motor M, and the document is sent out.

A feed belt 3 that winds around a feed roller 3A and rotates on the downstream side of the document feeding of the pickup roller 2;
Separate sheet feeding means comprising a double feed prevention roller 4 located below the sheet feeding means is provided. The separation sheet feeding means includes a drive motor M
Is transmitted via the electromagnetic clutch K2, and only the uppermost document of the plurality of documents sent out by the pickup roller 2 is separated and sent out.

A document passage detection sensor PS3, an intermediate conveyance roller 5, a curved guide plate 6
Is provided.

One document sent out by the separation sheet feeding means is detected by a document passage detection sensor PS3 at the leading end of the document, and then fed by a pair of intermediate transport rollers 5 in the vicinity thereof and passed between guide plates 6. Be fed. When the leading edge of a document passes through a document passing synchronization sensor (reversed document passing detection sensor) PS5 arranged in the middle of the feeding path, a detection signal is issued to control document transport. The document passing synchronous sensor
The PS5 controls the operation of a later-described original stopper 102, a drive motor M, a paper feed clutch K2, a transport clutch K1, and the like via a timer.

Next, the rotating conveyor belt 8 and the copier body 100
The original platen glass 1 (hereinafter referred to as the original platen glass) is conveyed while being nipped and held between the original platen glass for exposure of the original image (hereinafter, referred to as the original platen glass) 101 and the original stopper solenoid (latch type) SD3 is operated.
Original stopper 10 protruding from the upper left end of 01
The document stops at the position where the leading edge of the document abuts on 2.

The transport belt 8 includes a transport belt driving roller 9, a driven roller 10, three document pressing rollers 11, a tension roller,
It is stretched between twelve.

The original is exposed by an exposure lamp 103 in the copying machine main body 100 at a stop position on the platen glass 101, and a lens,
An original image is formed on a recording medium by scanning of an optical system including a mirror and the like.

When a series of copy processes for the manuscript is completed,
The abutting portion of the document stopper 102 retracts from the upper surface of the document table glass 101 to release the leading edge of the document, and the document is discharged by the transport belt 8 and the pair of discharge rollers 13 that have started to rotate again, and After the end passage is detected by the document discharge detection sensor PS, the document is discharged and placed on a discharge tray (document discharge table) 14.

Further, the automatic document feeder is provided with a document reversing unit 30 (right side in FIG. 1) for reversing the front and back of the document by the document reversing path. The document reversing unit 30 includes the conveying roller group 3
1, 32, 33, a guide plate 34, and a reversed document passage detection sensor PS5 for detecting a document passing through the inside of the reversing section 30 are arranged.

Next, a power drive system for the roller group and the belt will be described with reference to FIGS. 2, 3, and 4. FIG.

The drive motor M is a servomotor in which a DC motor and a speed control device (encoder, tachogenerator or the like) are integrated. A toothed belt B1 is stretched between each pulley of the toothed pulley P1 integral with the drive shaft 20 of the servomotor M and the toothed pulley P2 fixed to the intermediate shaft 21. It is rotated by the driving rotation of the motor M.

On the intermediate shaft 21, in addition to the toothed pulley P2, toothed pulleys P3, P4 and an electromagnetic clutch K1 are journaled. A tooth belt B2 is wound and meshed between the toothed pulley P3 and the toothed pulley P5 fixed to the shaft end of the transport belt driving roller 9 so as to be rotatable.

The driven roller 10 is rotated via the conveyor belt 8 by the rotation of the conveyor belt driving roller 9, and the toothed pulley P10 fixed to the shaft end of the driven roller 10 is toothed to the toothed pulley P11 via the toothed belt B5. Then, the paper discharge roller 13 is rotated.

Further, a toothed belt B3 that winds around and meshes with the outer periphery of the toothed pulley P4 provided on the intermediate shaft 21 has a shaft at a shaft end of a feed roller shaft 22 that rotates the feed roller 3A via gears G1 and G2. The toothed pulley P6 and the toothed pulley P7 attached to the shaft end of the intermediate transport roller shaft 23 integral with the intermediate transport roller 5 are wound and meshed with the respective outer peripheral teeth. Note that R
Reference numerals 1 and R2 denote tension rollers which circumscribe the outer peripheral surface of the toothed belt B3 and tension them.

By the rotation of the toothed belt B3, the feed roller shaft 22, which is integral with the toothed pulley P6, rotates the feed roller 3A via the gears G1, G2, and thereby the feed roller wound around the driven roller 3B. The belt 3 is rotated, and the toothed pulley is further rotated.
The pickup roller 2 is rotated by P8, P9 and the toothed belt B4. On the other hand, an electromagnetic clutch K2 is attached to the other end of the feed roller shaft 22, and is controlled based on an input signal to rotate the feed belt 3 and the pickup roller 2 to feed a document.

At the time of double-sided document copying, the document whose first surface has been exposed by the above-described process is rotated counterclockwise by the transport belt driving roller 9 in synchronization with the completion of the exposure. It is transported to the right.
The right end of the conveyed document is sent to the document reversing unit 30. Therefore, after the document D is successively pinched and conveyed around the inside of the document reversing section 30 by the conveying rollers 31, 32, and 33 along the guide plate 34, the right end of the document D, that is, the front end in this case is placed on the platen glass. Before the document is sent out onto the document 101, the rotation of the transport belt driving roller 9 is again switched clockwise based on the signal of the inverted document passage detection sensor PS5.

The above is the schematic configuration of the drive system transmitted by the drive rotor M. Next, the operation of the drive system will be described. 6 (B) and 6 (C) are schematic diagrams showing a document feeding / conveying process, FIG. 7 is a diagram showing a rotation speed of each paper feed roller by a drive system, and FIG. 8 is a block diagram of the drive system. FIG. 9 is a time chart.

When a bundle of originals is stacked on the original placing table 1 and abuts against the original leading edge stopper 1D stopped at the raised position, the original set detection sensor PS2 detects the presence or absence of the original and is set to the ADF mode.

When the width regulating plates 1A, 1A are moved and applied to the side edges of the bundle of documents, the document size detection sensor PS1 detects the width of the document, and the central processing unit (CPU ), The length of the document is converted and stored.

When the copy button 111 is pressed, a copy start signal is input, and the copier body 100 and the automatic document feeder are activated.

The ADF start signal causes the document set solenoid SD1
Is applied, and the leading edge of the document leading edge stopper 1D is lowered. At the same time, a voltage is applied to the paper feeding solenoid SD2, and the pickup roller 2 descends to press the uppermost layer of the document bundle.

At the same time, when the drive motor M starts to drive, the toothed pulley P1 on the motor drive shaft 20 rotates, and the toothed belt B1
, The intermediate shaft 21 having the toothed pulley P1 is rotated.
At this time, the electromagnetic clutches K1 and K2 are both ON, and the feed roller shaft 22 is driven and rotated by the rotation of the toothed belt B3, and the feed belt 3 is rotated via the gears G1, G2 and the feed roller 3A. Then, the pickup roller 2 is further rotated by the toothed belt B4. At the same time the above toothed belt
The toothed pulley P7 meshing with B3 is also rotated to rotate the intermediate transport roller shaft 23, and the intermediate transport roller shaft 5 is in a rotating state.

At the same time, the toothed belt B2 wound around the intermediate shaft 21 rotates the transport belt driving roller 9 having the toothed pulley P5. This allows the roller 9 and the driven roller
The conveyor belt 8 wound between 10 is rotated. At this time, the peripheral speeds of the pickup roller 2, the feed belt 3, the intermediate transport roller 5, and the transport belt 8 are all in the high-speed transport mode v ₁ (for example, the peripheral speed v ₁ = 1200 mm / sec).

By the rotation of each roller and the rotation of the belt, the document table 1
The uppermost original D1 of the upper bundle is sent out by the pickup roller 2, separated by the feed belt 3 and the double feed prevention roller 4, and the first uppermost original D1 is separated and fed at the original main transport speed. Sent.

When the leading edge of the separated document D1 passes through the document passage detection sensor PS3, a line and other passage signal is generated, and a timer starts from the generation of this signal. Turn off. As a result, after the leading end of the document D1 has passed the nip position by the intermediate conveyance roller 5, the drive rotation of the pickup roller 2 and the feed belt 3 is stopped, and the rotation is driven.

Subsequently, the intermediate conveyance roller 5 is driven and rotated to feed the document D1, passes through the document passage synchronization sensor PS5, and is then nipped by the rotating conveyance belt 8 so that the document D1 is placed on the document table glass 101 at the document main conveyance speed. Skating with

At time t6 after the passage of the original by the original passage synchronization sensor PS5, the original stopper solenoid SD3 is operated, and
The document stopper 102 projects from the upper surface of the left end of the document table glass 101. As shown in FIG. 10, the document stopper 102 is a latch type solenoid via an operation lever 104 and an arm special upper plate 103.
It is linked to SD3 plunger SD3A. The arm special upper plate 103 is rotatable around the support shaft 103A,
The lower end is connected to the pin on the plunger SD3, and the upper end is in contact with one end of the operating lever 104. The operation lever 104 is slidable in the oblique vertical direction, and is pin-coupled to the original stopper 102 to move the original stopper 102 in the oblique vertical direction. A stopper pin 105 fixed to a part of the document stopper 102 abuts on both ends of the stopper regulating plate 106 to regulate the upper limit position of the document stopper 102 and the lower limit position thereof. The document stopper 102 is pushed up by the suction of the solenoid SD3, and is set at a predetermined position. This solenoid SD3 is a latch type.
Unless reset, the state of suction is maintained.

The time before the leading edge of the document arrives at the document stopper 102, i.e., at time t9 after the document passage of the document passing synchronization sensor PS5, the drive motor M is temporarily turned off, the brake is applied, and the drive is stopped. I do. However, due to the inertial movement of the drive means, each drive member continues to operate to some extent, and both the original and the conveyance are continued. For this motor brake, a method of short-circuiting both terminals of the motor M or applying a reverse voltage is effective.

Then, at time t8, the transfer clutch K1 is turned off,
The transport belt 8 is controlled to stop the transport belt 8. However, the document also slips on the transport belt 8 due to inertia and stops at a position at which the document has passed the stopper 102, that is, the document advances at a speed equal to or lower than the document main transport speed. Stop at the end. At this time, t8 is the time before the conveyance belt 8 stops.
By increasing the speed and gently lowering the speed, the amount of movement of the original document is increased, but it is clear that t8 ≧ t10 may be satisfied.

All of the above is controlled so that the document is conveyed at a speed that stops at the position where the document has passed the document stopper 102 and hits the document stopper 102. A method of controlling the progress of the document so that the speed monotonously decreases as shown in FIG. 11 (A), and a method of gradually controlling the speed after reducing the speed as shown in FIG. 11 (B). There is.

The clock is switched from high speed to low speed almost simultaneously with the clock t8.

At time t10, the feed clutch K2 is turned on and the drive motor M is turned on.
Drive. As a result, the next original D2 is fed by the pickup roller 2 and the feed roller 3.

In the original stationary state in the image exposure section, scanning exposure by the optical system 103 on the copying machine main body 100 side is started. At this time, the next original D2 is sent out before or during the scanning exposure, fed through the feed roller 3 and the intermediate transport roller 5, and when the leading end of the next original D2 passes through the original passing sensor PS3, a detection signal is issued. The document D2 is stopped at a predetermined position by the time t (or the pulse count by the counter) measured by the timer and kept in a standby state. During this time, the electromagnetic clutch K2 for feeding is ON, since the conveying electromagnetic clutch K1 is set to OFF, the preceding document D1 in the exposure has been stopped, the subsequent document D2 in the low-speed feed mode v ₂ during this time The document is fed, and its leading portion reaches the vicinity of the document table glass 101 and stands by. However, the speed of v ₂ (for example, v ₂ = 500 mm / sec) is determined so that the operation during this period is completed at least after the scanning is completed and before the restart signal is generated.

The subsequent document standby position is set differently depending on various document sizes, that is, the length of the document in the transport direction.

FIG. 6B shows the feeding and feeding of the preceding document D1 and the following document D2.
It is a schematic diagram which shows a conveyance process.

When the leading end of the following document D2 has passed the document passage detection sensor PS3, time measurement by a timer is started, and after t2, the paper feed clutch K2 is turned off and paper feeding is stopped. next,
The drive of the drive motor M is stopped after the time t14 measured by the timer from the time when the leading end of the document D2 has passed the document passing synchronization sensor PS5. Note that the original at the above-mentioned pause position P
The leading end of D1 is located near the platen glass
Because it is a position where it is not pressed against the original, it is close to the rear end of the preceding document by a short distance.

Next, at the end of the scanning exposure, an ADF start signal is issued from the copying machine main body 100 to perform an exposure operation on the second document. That is, by turning on the drive motor M and turning on the electromagnetic clutch K1 for conveyance, the preceding document D1 is conveyed by the conveyance belt 8 and discharged / placed on the discharge tray 14 via the discharge rollers 13. You. At the same time, the subsequent document D2 is nipped and slid on the platen glass 101 from the standby position, reaches the document stopper 102 by the above-described stop operation, and ends the document exchange. it is a high-speed transport mode v _1.

Timers t5, t6, t7, t8, t by the above ADF start signal
9, t10 starts at the same time. Timers t6 and t7 activate setting of document stopper solenoid SD3, and timers t5 and t11 activate resetting of solenoid SD3. Also, timer t
8 issues an OFF signal of the transport clutch K1. In addition, a timer
t9, t10 and t14 control ON / OFF of the drive motor M.

The second document D2, in the high speed mode V ₁ from the temporary stop position P2, is conveyed onto the platen glass 101, after a pause in timing t9, through the similar process, the document stopper 10 by inertia
Stops when it hits 2. Thereafter, the same operation as that of the preceding original D1 is performed, and the exposure processing and the discharge are performed.

In this embodiment, one motor and two electromagnetic clutches control and operate the above two drive systems. However, a similar operation can be performed by two motors and one electromagnetic clutch. .

Also, when a two-sided original is copied, the original is reversely fed to the original reversing unit 30, inverted, and transported to the original platen glass 101 again. The same effect can be obtained by setting the pause position of the document.

〔The invention's effect〕

As described above, according to the automatic document feeder of the present invention, it is possible to reliably transport a document at a high speed, and therefore, it is possible to reduce the document transport time. It is effective for smooth document transport, prevention of document tip damage and jam occurrence, etc.
The original can be reliably stopped at a predetermined position, the original transport drive motor is stopped, and the inertial rotation of the original causes the original to hit the original with a force exceeding the stopper. Therefore, the document does not stop before the document stopper.

In addition, the load on the motor can be reduced, power consumption can be reduced, and a small motor with low torque can be provided. In particular, for document transport, the motor, clutch, solenoid, and various timers are started based on the ADF start signal from the copying machine.
Since the control is performed by the passage detecting means of the preceding document, there is an advantage that the control program is simple and clear, the number of malfunctions is small, and the manufacturing cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a document conveyance path of the automatic document conveyance device according to the present invention, FIG. 2 is a configuration diagram showing a drive system (power transmission system) of the automatic document conveyance device, and FIG. FIG. 4 is a perspective view showing a transport system and a drive system, and FIG. 4 is a plan view of a main part of the automatic document transport device. FIG. 5 is an external perspective view of the upper part of the copying machine equipped with the automatic document feeder. 6A, 6B, and 6C are schematic diagrams showing a document conveying process;
FIG. 7 is a diagram showing the rotation speed of each paper feed roller by the drive system, FIG. 8 is a block diagram of the drive system, FIG. 9 is a time chart of a document feeding process, FIG. No.
FIGS. 11A and 11B are diagrams showing deceleration control of document conveyance. 1 Document placement table, 1A Width control plate 1B Pinion gear, 1C Rack gear 1D Document stopper 2 Pickup roller 3 Feed belt 3A Feed roller 4 Heavy Feed prevention roller, 5: Intermediate transport roller 6: Guide plate, 8: Transport belt 9: Transport belt drive roller 13: Discharge roller, 14: Discharge tray 30: Document reversing section, 31, 32, 33: transport roller group 34: guide plate, 100: copier body 101: image exposing unit (document table glass) 102: document stopper, 103: lever lifting plate 105: stopper pin, 106 Stopper control plate 110 Control panel 111 Copy button K1, K2 Electromagnetic clutch (MC) M Drive motor D Document D1 Preceding document D2 Subsequent document PS1 Original size detection sensor PS2 …… Original set detection sensor PS3 …… Original Passage detection sensor PS4: Document ejection detection sensor PS5: Reversed document passage detection sensor (document passage synchronization sensor) SD3: Latch type solenoid v _1: High speed conveyance mode, v _2: Low speed conveyance mode

Claims (1)

(57) [Claims] A plurality of sheet-like originals are sequentially conveyed to an image exposing section by an original conveying means including an original conveying belt, and the retractable original stopper provided at one end of the image exposing section is projected. To stop at a predetermined position, perform scanning exposure by moving the optical system, and after the exposure, discharge the document to a document discharge tray, wherein the document is transferred to the image exposure unit at a document main transport speed. When the document is conveyed and approaches a document stopper for stopping at a predetermined position of the image exposure unit, the document is moved at a speed equal to or less than the document main transport speed by the inertial motion of the document transport unit, and the document exceeds the document stopper position. An automatic document feeder comprising: control means for stopping the driving force of the document feed belt so as to press against the document stopper at a stopping speed; and control means for projecting the document stopper. .