JPH03102045A - Automatic document transport device - Google Patents

Abstract

PURPOSE:To surely transport a document at high speed by slowing down a document transport speed to a second setting speed slower than a prescribed transport speed before the extreme end of document reaches a stopper, hereafter transporting the document at the setting speed, and stopping the document through abutting against the stopper at the second setting speed. CONSTITUTION:At the time before the extreme end of a document reaches a document stopper 102, namely, after timing t9 from passing through of a synchronizing sensor PS5 at the document for example, a driving motor M is temporarily OFF and braked. The driving motor M begins to reduce its speed, and at timing t21 transport speed of the document becomes a prescribed middle transport speed v3, for example v3=800mm/sec, and at this point the motor is again ON. The document D1 is transported at the speed v3 up to timing t22. The transport speed v3 is considered as the speed at which the document D1 reaches a discharge paper sheet detecting sensor PS4, but actually the document is stopped at the document stopper 102. Namely, at timing t22 the motor M is again OFF, and the document D1 is stopped.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] 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 is generally used by being mounted on a document table glass (platen glass) of an image exposure unit of a copying machine or the like.

In an optical system moving type copying machine equipped with this automatic document feeder, the automatic document feeder feeds sheets of originals (hereinafter simply referred to as originals) one by one from the document tray (stack section) on which they are placed. The document is fed onto a document table glass by a conveyor belt, exposed there by an exposure section lamp in the main body of the copying machine, and then further conveyed onto a thick document discharge table.

Conventionally, the operation of exchanging originals on the original platen glass by such an automatic document conveying device takes a long time to exchange the originals, and therefore, a large amount of copying processing time is required, resulting in a decrease in copy productivity. For this reason, it is required to transport and stop the document more quickly and reliably.

[Problem to be solved by the invention]

When using an automatic document feeder to automatically feed and eject documents onto the document table, copy productivity can be increased by 10% if the document is exchanged within the return time of the scanning optical system.
It becomes 0% and no time is wasted.

To achieve this, it is necessary to increase the document transport speed from the document double-feed prevention position in the stack unit to the document stop position on the document table glass surface.

However, if the document is transported at a high speed and at a constant speed, it may be difficult to always stop the document at a predetermined position due to friction between the document and the platen glass, variations in load, etc. Become certain. Therefore, even if the document stopper is used to stop the document, the leading edge of the document that is loaded at high speed may be damaged or jams may occur.

[Means to solve the problem]

The object of the present invention is to solve the above-mentioned problems in an automatic document feeder and to increase the number of copies processed.

The automatic document feeder of the present invention, which achieves the above object, separates each document from a stack of documents stacked on a document placement table and feeds the documents to an image exposure section, and transports the documents by a document conveyance means. In an automatic document feeder in which the image exposure unit is brought into contact with a document stopper and stopped at a predetermined position, the optical system is moved to scan and expose the document surface, and the document is conveyed to a document eject table after exposure. , the document is conveyed by the document conveying means on the document table glass of the image exposure section at a predetermined conveying speed, and before the leading edge of the document reaches the stopper, the document conveying means is conveyed at a speed lower than the predetermined conveying speed. Thereafter, the document is conveyed at the second set speed, and the document is brought into contact with the document stopper at the second set speed and stopped.

Further, in the automatic document feeder of the present invention, the document stopper υ1
A paper ejection sensor is provided on the downstream side in the paper direction, and the original reaches the paper ejection sensor position when the document stub 1 and the flap are in a retracted state and the document does not hit the document stopper.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 1 is a diagram showing the structure of the document conveyance path of the automatic document feeder according to the present invention, and FIG. 2 is a diagram showing the drive system of the automatic document feeder (
FIG. 3 is a perspective view showing the document conveyance system and drive system inside the automatic document conveyance system, and FIG. 4 is a plan view of the main parts of the automatic document conveyance device. Furthermore, Figure 5 shows a copying machine equipped with an automatic document feeder. It is an external perspective view of the E section. FIG. 6(A) is a schematic diagram showing the document conveyance 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 explained with reference to FIGS. 1, 3, 5, and 6(A).

A document placement table 1 is provided on the left side of the upper surface of the automatic document feeder, and allows documents to be stacked on top of each other.

A document leading edge stopper ID is provided below the leading edge of the document placement table l and is swingable by the document setting solenoid SDI and the solenoid SDl. With the upper end of the leading edge stopper ID protruding near the leading edge of the document mounting table L, place the document stack on the document mounting table L, and abut the leading edge of the document stack against the document leading edge stopper ID. Arrange the paper.

When a stack of originals is placed on the original platen l, the presence or absence of originals on the original platen is detected by the original set detection sensor (original zero sheet detection sensor) PS2, and the ADF mode is displayed on the control panel lO of the copying machine main body 100. is displayed.

Width regulating plates IA, IA are provided on the document mounting table l to regulate the width direction of the document. The width regulating plate IA is formed by rack gears IA that can alternately slide laterally across the binion gear IB on the lower surface of the original table L.
C and IC, respectively, and can be moved symmetrically around the center. The rack gears 1c and IG are connected to width regulating plates 1A and IA, respectively, and the amount of movement thereof is detected by a document size detection sensor PS1, so that the width size of the document can be read. Based on this read value, the length of the standard size document D is automatically converted. Therefore, place the document stack on the document placement table L, and press the width regulating plate IA.
, IA are slid and brought into contact with the width of the document, so that various document sizes, that is, the lengths of each document are stored.

A big up roller 2 is located above and near the tip of the document table l, and is movable up and down by the operation of a paper feed solenoid SD2 and spring pressure, and is also rotatable by the driving force of a drive motor M. By operating the copy button 111 on the control panel 110, the automatic document feeder is started, the paper feed solenoid SD2 is energized and activated, and the pick-up roller 2 connected thereto is lowered to feed the stack of documents. Press against the top surface,
At the same time, the document begins to rotate by the driving force of the drive motor M and the document is sent out.

On the document feeding downstream side of the pickup roller 2, there is a feed belt 3 that rotates around a feed roller 3A;
Separation sheet feeding means is provided which includes a double feeding prevention roller 4 located below the sheet feeding mechanism. The separation sheet feeding means is driven by a drive motor M.
The driving force is transmitted through the electromagnetic clutch K2, and only the uppermost one of the plurality of originals sent out by the pickup roller 2 is separated and sent out.

On the document feeding downstream side of the separation sheet feeding means, a document passage detection sensor PS3, an intermediate conveyance roller 5, and a curved guide plate 6 are provided.
is provided.

The passage of the leading edge of the original sheet sent out by the separation sheet feeding means is detected by the original passage detection sensor PS3, and is then fed by a pair of intermediate conveyance rollers 5 in the vicinity, passing between the guide plates 60. will be delivered. When the leading edge of the original passes through the original passage synchronization sensor (inverted original passage detection sensor) PS5 located in the middle of this feeding path,
Emit a detection signal to control document transport. The document passage synchronization sensor PS5 is a document stopper 102, which will be described later. The operation of the drive motor M, paper feed clutch K2, transport clutch K1, etc. is controlled via a timer.

Next, the rotating conveyor belt 8 and the copying machine main body 100
The document is conveyed while being pinched between the original platen glass for exposing the original image on the upper surface (hereinafter referred to as the document platen glass) 101, and is projected from the upper surface of the left end of the document platen glass 101 by the operation of the document stopper solenoid (latch type) SD3. The document stops at the position where the leading edge of the document abuts the document stopper 102 which is set to .

The conveyance belt 8 is stretched between a conveyance belt driving roller 9, a driven roller 1O, three document pressing rollers 11, and a tension roller 12.

The original is exposed to light by an exposure lamp 103 inside the copying machine main body at a stop position on the original platen glass 10l.
An original image is formed on a recording medium by scanning with an optical system such as a mirror.

When a series of copying processes for the original document is completed, the abutting portion of the original stopper 102 touches the original platen glass 10.
The leading edge of the document is released by retracting from the top surface of 1, and the conveyor belt starts rotating again +- 8. The document is carried out by a pair of paper ejection rollers l3, and the document is ejected when the trailing edge of the document passes. After being detected by the detection sensor PS4, the document is discharged and placed on the paper discharge tray (*document discharge table) 14.

Furthermore, this automatic document feeder is provided with a document reversing section 30 for reversing the front and back of the document using the document reversing path. The document reversing unit 30 includes a transport roller group 31.32.3.
3, a guide plate 34, and an inverted original passage detection sensor PS5 for detecting an original passing through the inversion section 30.

Next, Figures 2 and 3. *4 The power drive system for the roller group and belt will be explained with reference to Figure 4.

The drive motor M is a servo motor that integrates a DC motor and a speed control device (encoder, tacho generator, etc.). A toothed pulley P1 that is integrated with the drive shaft 2o of the servo motor M, and a toothed pulley P2 that is fixed to the intermediate shaft 2l.
A toothed belt Bl is stretched between the respective boars, and the intermediate shaft 2l is rotated by the driving rotation of the motor M.

In addition to the toothed pulley P2, toothed pulleys P3 and P4 and an electromagnetic clutch K1 are mounted on the intermediate shaft 2l. The toothed pulley P3 and the conveyor belt drive roller 9
There is a toothed pulley P5 fixed to the shaft end of the
The toothed belt B2 can be rotated by winding and toothing.

The conveyor belt 8 is rotated by the rotation of the conveyor belt drive roller 9.
The driven roller 10 rotates through the shaft end of the driven roller IO, and the toothed pulley PIO fixed to the shaft end of the driven roller IO meshes with the toothed pulley Pll through the toothed bell B5, and rotates the paper ejection roller 13. let

Further, a toothed belt B3 that winds around and meshes with the outer periphery of a toothed pulley P4 provided on the intermediate shaft 2l is connected to a feed roller 3.
A is gear Gl. A toothed pulley P6 is attached to the shaft end of the feed roller shaft 22 rotated via G2, and a toothed pulley P7 is attached to the shaft end of the intermediate conveyance roller shaft 23 that is integrated with the intermediate conveyance roller 5. It is wound around and meshed with each outer peripheral tooth part of. Note that Rl and R2 are tension rollers that are placed under tension while circumscribing the outer peripheral surface of the toothed pelt B3.
Le.

Due to the rotation of the toothed belt B3, the seven feed roller shaft 22, which is integral with the toothed pulley P6, rotates the feed roller 3A via the gears Gl and G2.
Rotate the 7-eed belt 3 wound between the
Rotate the pickup roller 2. 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 seven feed belt 3 and the big up roller 2 to feed the document.

When copying a double-sided document, the conveyor belt drive roller 9 starts rotating counterclockwise in synchronization with the completion of exposure of the document whose first side has been exposed in the above-described process, so that the conveyor belt 8
The document is conveyed rightward on the document table glass 101 by the document table glass 101.

The right end portion of the transported document is sent to the document reversing section 30. Therefore, the document D is conveyed around the document reversing section 30 along the guide plate 34 while being supported by the conveyance rollers 31, 32, and 33, and then the right end of the document D, that is, the leading edge in this case, is Before the document is sent out onto the base glass 101, the rotation of the conveyor belt drive roller 9 is switched clockwise again based on a signal from the document passage detection sensor PS5 in which the leading edge of the document is reversed.

The above is a schematic configuration of a drive system to which power is transmitted by the drive motor M. Next, the operation of the drive system will be explained. Figures 6 (B) and (C) are schematic diagrams showing the document feeding and conveyance process, Figure 7 is a diagram showing the rotational speed of each paper feed roller by the drive system, and Figure 8 is a block diagram of the drive thread. 9 are time charts.

■ When a stack of originals is loaded on the original platen 1 and hits the original end stopper ID which is stopped at the raised position 1.2, the original set detection sensor PS2 detects the presence or absence of originals and the ADF
mode is set.

(2) When the width regulating plates IA, IA are moved and brought into contact with the width side edges of the document bundle, the document size detection sensor PS1 detects the document width, and the CPU converts and stores the document length.

■ Copy button]. I. When l is pressed, a copy start signal is input, and the copying machine main body 1008 and automatic document feeder are activated.

(2) This ADF activation signal applies a voltage to the document setting lens SDI, and lowers the tip of the document tip stopper 1D. At the same time, a voltage is applied to the paper feed solenoid SD2, and the big up roller 2 descends to press the top layer of the document bundle.

(2) At the same time, when the drive motor M starts driving, the toothed pulley Pl on the motor drive shaft 20 rotates, and the intermediate shaft 2l having the toothed pulley PI is rotated via the toothed belt Bl. At this time, both electromagnetic clutches K1 and K2 are set to O.
The feed roller shaft 22 is driven and rotated by the rotation of the toothed bell 1 and B3, and the gear Gl. G2
, the seven feed belt 3 is rotated via the feed roller 3A, and the pickup roller 2 is also rotated by the toothed belt B4. At the same time, the toothed belt P7 meshing with the toothed belt B3 is also rotated, and the intermediate conveying roller shaft 23 is rotated.
is rotated, and the intermediate conveying roller shaft 5 becomes a rotating shaft.

At the same time, the toothed belt B2 wound around the intermediate portion 1i11i21 rotates the conveyor belt drive roller 9 having the toothed pulley P5. As a result, the roller 9
and the driven roller lO; rotates the conveyor belt 8. At this time, the circumferential speeds of the pickup roller 2, feed belt 3, intermediate conveyance roller 5, and conveyance belt 8 are all set to high-speed conveyance mode, and the document conveyance speed is v+
(For example, V.=1200 mm/sec).

As a result of the above-mentioned rotation of each roller and rotation of the belt, the top layer document D1 of the document stack on the document table l is sent out by the pickup roller 2, and is separated by the feed belt 3 and the double feed prevention roller 4, The lth document DI is fed separately.

■ When the leading edge of the document DI that has been separated and fed passes the document passing detection sensor PS3, a leading edge passing signal is generated, and the timer starts timing from the generation of this signal.
After counting the time, paper feed clutch K2 is turned off. As a result, after the leading edge of the document Di passes the nib position by the intermediate conveyance roller 5, the driving rotation of the big up roller 2 and the feed belt 3 is stopped, and the driving rotation becomes driven rotation.

■ The intermediate conveyance roller 5 is then rotated and the document DI
Basically, the document is fed, passes the document passage synchronization sensor PS5, and then slides on the document table glass 101 while being pinched by the rotating conveyor belt 8. These detailed operations are shown in Figure 9 (A). (B) and FIG. 10, and will be described in detail later.

■ Time is measured from the time when the original passes through the synchronization sensor PS5.
At f3t&, the document stopper solenoid SD3 is activated, and the document stopper 102 projects to the upper surface of the left end of the document table glass l. The structure is such that the stopper 102 is pushed up and set by suction from the solenoid SD3.

This solenoid SD3 is a latch type, and even if the power is turned off, the suction state is maintained unless reset.

(2) At a time before the leading edge of the document reaches the document stopper 102, that is, 70 minutes after the document passes through the synchronization sensor PS5, the drive motor M is temporarily turned off and the brake is applied. Then, the drive motor M begins to decelerate, and at time t21, the document transport speed changes to the predetermined medium speed transport mode vs.
(for example, vs-800 mm/sec), and then the motor M is turned on again. And the manuscript DI is timed t 2
2 is transported at a speed of v3.

This conveyance speed V, is considered to be the speed at which the document DI reaches the discharge detection sensor PS4, but in reality, the document is stopped at the document stopper 102. That is, at time t22, the motor M is turned on again.
is set to OFFL, thus stopping the original DI. . However, due to inertia, each drive unit continues to operate to some extent, and the document continues to be transported. For this motor brake, it is effective to short-circuit both terminals of the motor M or apply a reverse voltage.

[Phase] Then, turn off the conveyance clutch K1 at timing 78.
Then, the conveyor belt 8 is stopped. However, even here, the document advances while the conveyance belt 8 is decelerated due to the inertia of the conveyance system, but since there is the document stopper 102, the document does not move while hitting the document stopper 102.

In all of the above, the document is controlled so as to prevent the document from suddenly hitting the document stopper 102 and damaging the leading edge of the document, and to gradually decelerate and convey the document so that it hits the document stopper 102.

Then, almost at the same time as this timing of 8t, the clock is switched to low speed.

(2) Turn on the paper feed clutch K2 and drive the drive motor M at time tlO. As a result, pink up roller 2
Then, the next document D2 is fed by the feed roller 3. (FIG. 9B) While the document is in a 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, before or during scanning exposure, the next original D
When the leading edge of the next document D2 passes through the document notification detection sensor PS3, a detection signal is generated and time is measured by a timer (or pulse count by a counter). As a result, the document D2 is stopped at a predetermined position and kept on standby.

During this time, the paper feeding electromagnetic clutch K2 is turned OFF when the document is nipped by the intermediate conveyance roller 5, in order to further prevent the subsequent document feeding from double feeding. Electromagnetic clutch K for transportation
Since l is set to OFF, the preceding original document DI being exposed is in a stopped state, but the subsequent original document D2 is fed in the low-speed transport mode v2 during this time, and its leading edge is near the document platen glass 101. Reached and waiting. However, the speed of the low speed paper feeding mode v2 (for example, V2 - 500 mm/see) is determined so that the operation during this period is completed at least after the end of scanning and before the restart signal is generated.

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

FIG. 6(B) is a schematic diagram showing the process of feeding and conveying the preceding original D1 and the succeeding original D2.

Timing by the timer is started from the time when the leading edge of the subsequent document D2 passes the document passage detection sensor PS3, and t2
Afterwards, the paper feed clutch K2 is turned off and paper feeding is stopped. Next, the driving of the drive motor M is stopped after the timer has elapsed time tl4 from when the leading edge of the document D2 passes the document synchronization sensor PS5. In addition, the above temporary stop position P
The leading edge of the document D2 located at 1 is located near the document table glass 101 and is not in pressure contact with the conveyor belt 8, so it is close to the trailing edge of the preceding document at a short distance.

■ Next, at the end of the scanning exposure, from the copying machine main body 100
A DF start signal is issued and the exposure operation for the second original is performed. That is, by turning on the drive motor M and turning on the electromagnetic clutch Kl for conveyance, the preceding document D1 is conveyed by the conveyance belt 8, and is discharged and placed on the paper discharge tray l4 via the paper discharge roller l3. . At the same time, the succeeding original D2 slides on the original platen glass 101 from the standby position, and reaches the original stopper 102 in the stopping operation, thereby completing the original exchange. Note that the document conveyance according to the time measurement t8 at this time is in the medium speed conveyance mode and the speed is v3.

■ Time measurement by a timer based on the above ADF start signal 5. t 6, t 7. t8. t9. tlO starts at the same time. Timing t6 and t7 actuate the setting of the document stopper solenoid SD3, and timing (5 and tll actuate the reset of the solenoid SD3. Also, the timer t
8 issues an OFF signal for the transport clutch K1. Furthermore, time measurement t9. tlO and t'14 are the ON.
Controls OFF.

The second document D2 is conveyed from the temporary stop position P2 to the document table glass 101 through a conveyance speed v1 in the high speed mode to a conveyance speed V in the medium speed mode, and is conveyed onto the document table glass 101 at a time t.
After it is temporarily stopped at 9, it goes through the same process as described above, and then due to inertia it hits the document stopper 102 and stops. Thereafter, it is operated in the same manner as the preceding document DI, and is subjected to exposure processing and discharged.

In this example, the two drive systems described above are controlled and operated using one motor and two electromagnetic clutches, but it is also possible to perform similar operations using two motors and one electromagnetic clutch. .

Also, when copying a double-sided original, when the original is reversely fed and reversed to the original reversing unit 30 and then transported to the original platen glass again, the timing starts from the passage detection of the reversed original passage detection sensor PS5, and the original is processed as described above. A similar effect can be obtained by setting a temporary stop position.

Furthermore, if the paper discharge detection sensor PS4 issues a signal within a certain period of time after the ADF starts operating, the copying machine will detect the occurrence of a through jam from this signal and take measures such as issuing an alarm. You can take it.

Although the above-described embodiment describes an automatic document feeder having a two-stage speed change means of a low paper feeding speed and a high conveyance speed, the present invention is not limited to this embodiment, and can be applied to other general automatic document feeders. The present invention can be widely applied to devices that start feeding the next document from the stack position at the same time as the discharge of the preceding document starts, and devices that start feeding the next document after detecting the discharge of the preceding document.

〔Effect of the invention〕

As described above, according to the automatic document feeder of the present invention, it is possible to reliably feed documents at high speed, which not only makes it possible to shorten document feed time but also stabilizes separation performance. This is effective for improving the document transport speed, smoothing the document conveyance, preventing damage to the leading edge of the document, and preventing the occurrence of jams, and it is possible to reliably stop the document at a predetermined position.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing the thick document transport path of the automatic document feeder according to the present invention, and FIG. 2 is a drive system of the automatic document feeder (
FIG. 3 is a perspective view showing the document conveyance system and drive system inside the apparatus, and FIG. 4 is a plan view of essential parts of the automatic document conveyance device. Furthermore, FIG. 5 is an external perspective view of the upper part of the copying machine equipped with an automatic document feeder. Figure 6 (
A), (B), and (C) are schematic diagrams showing the document conveyance process, FIG. 7 is a diagram showing the rotational speed of each feeding roller by the drive system, FIG. 8 is a block diagram of the drive system, and FIG. Figure (A)
．． CB) is a time chart of the document feeding and conveying process, No.
Diagram O is a speed diagram and a time chart of the drive motor. 1... Original table IA... Width regulation plate IB
...Binion gear IC...Rack gear ID...
・Document leading edge stopper 2...Pickup roller 3...7 Eat Helt 3A...Feed roller 4...Double feed prevention roller 5...Intermediate conveyance roller 6
... Guide plate 8 ... Conveyor belt 9 ...
Conveying belt drive roller l3... Paper ejection roller l4... Paper ejection tray 3
0... Original reversing section 31.32.33... Conveyance roller group 34... Guide plate 100...
Copying machine main body 101...image exposure section (w. platen glass)
102... Original stopper 110... Control panel Ill... Copy button Kl, K2... Electromagnetic clutch (MC) M... Drive motor D... Original DI... Preceding original
D2...Subsequent original PSl...Original size detection sensor PS2...Original set detection sensor PS3...Original passage detection sensor PS4...Original discharge detection sensor PS5...Reversed original passage detection sensor (original Passage synchronization sensor) SD3... Latch type solenoid v1... High speed transport mode v1... Low speed paper feeding mode V,... Medium speed transport mode

Claims (2)

[Claims] (1) Separate sheets one by one from a stack of originals placed in a stack on a document placing table and feed them to an image exposure section, and bring the originals into contact with a document stopper in the image exposure section using a document conveying means. In an automatic document feeder that stops at a predetermined position, moves an optical system to perform scanning exposure on the surface of the document, and transports the document to the document ejection table after exposure, the document is placed on the document table glass of the image exposure section. Before the leading edge of the document reaches the stopper, the document is conveyed at a predetermined conveyance speed by the document conveyance means, and the document conveyance means is lowered to a second set speed that is lower than the predetermined conveyance speed. Convey at a second set speed,
An automatic document feeder characterized in that the document is stopped by hitting the document stopper at the second set speed. (2) A paper ejection sensor is provided on the downstream side of the document stopper in the paper ejection direction, and when the document stopper is in the retracted state and the document does not hit the document stopper, it is possible to prevent the document from reaching the paper ejection sensor position. The automatic document feeder according to claim 1.