JP2687016B2 - 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]

The automatic document feeder is generally used by mounting it on a platen glass (platen glass) of an image exposure unit such as a copying machine. In an optical system movable copying machine equipped with this automatic document feeder, sheets are fed one by one from an original placing table (stack section) on which sheet-like originals (hereinafter simply referred to as originals) are placed. The document is fed onto the platen glass by a conveyor belt, exposed here by an exposure section lamp in the main body of the copying machine, and then carried out onto the document discharge table.

In the document exchange operation on the platen glass by such an automatic document feeder, conventionally, after detecting that the document on the platen has been ejected by the sheet ejection sensor, the next document is sent out from the stack section and the original platen glass is ejected. It was transported to the top and stopped at a predetermined position. For this reason, it takes a long time to replace the original, and thus a long copy processing time, resulting in low copy productivity.

[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, increasing the document conveying speed causes various problems such as an increase in the size of the motor, an increase in power consumption, an increase in the degree of document breakage, and a decrease in document separation performance.

[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.

The automatic document feeder of the present invention that achieves the above-mentioned object conveys a plurality of sheet-like documents sequentially to the image exposure unit, stops the documents at the image exposure unit, and moves the optical system to perform scanning exposure. In an automatic document feeder for carrying out the original document to an original document delivery table after exposure, a detecting means for detecting the original size by the moving position of the lateral width regulating plates on both sides of the original document on the original document table, and the exposure of the preceding sheet original document Before the end of the operation, the registration roller that starts feeding the succeeding sheet-like original, the detection sensor that detects the passage of the succeeding sheet-like original, and the sheet-like sheet that is being conveyed after a predetermined time has elapsed based on the detection sensor signal. Before the document is inserted between the platen glass and the transport belt, the document is temporarily stopped in the transport path and stands by until it is discharged from the exposure position of the sheet document of the preceding document. The detection signal of the size is characterized in that the variably set the pause position of the document to the subsequent.

Further, the automatic document feeder of the present invention sets at least two subsequent document temporary stop positions according to the document size, and sets the distance between the trailing edge of the preceding document and the leading edge of the temporarily stopped subsequent document on the transport path. It is characterized in that the pause position changed according to the document size is set.

Further, the automatic document feeder of the present invention is characterized in that the document feeding operation speed for feeding to the temporary stop position is equal to or lower than the document feeding speed on the image exposure unit.

〔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 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. 6 (A), (B), and (C) are schematic diagrams showing a document conveying process. 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, 5, and 6A.

A document table 1 is provided on the left side of the upper surface of the automatic document feeder, and one or more documents can be placed at a predetermined position.

When the original stack is placed on the original placing table 1, the presence or absence of the original on the original placing table is detected by the original set detection sensor (zero original detection sensor) PS2, and the control panel 1
ADF mode is displayed on 10.

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 movement amount thereof is detected by the document size detection sensor PS1, so that the horizontal size 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, various original sizes, that is, respective original lengths are stored by placing the original stack on the original placing table 1 and sliding the lateral width regulating plates 1A, 1A into contact with the lateral width of the original.

Next, by operating the copy button 111, the pickup roller 2 is lowered by using the lowering means and comes into contact with the uppermost surface of the document stack, and at the same time, rotation is started and the document is sent out.

At the same time, the feed belt 3 that rotates and rotates the feed roller 3A, which is a registration roller that has started driving rotation, and the double feed prevention roller 4 located below the feed belt 3 cooperate to feed only the top document. .

One sheet of the sent-out original is fed by a pair of intermediate conveying rollers 5.
Thus, it is conveyed between the curved guide plates 6 and passes through the document passage detection sensor PS3. Then, it is conveyed while being pinched between the rotating conveyor belt 8 and an original image exposure original platen glass (hereinafter referred to as an original platen glass) 101 on the upper surface of the copying machine main body, and is projected from the upper surface of the original platen glass 101. The document stops at the position where the leading edge of the document hits the document stopper 102.

The conveyor belt 8 is stretched between a conveyor belt driving roller 9, a driven roller 10, three document pressing rollers 11 and a tension roller 12.

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

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 carried out 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 PS4, the document is discharged and placed on a discharge tray (document discharge table) 14.

Further, this automatic document feeder is provided with a document reversing unit 30 for reversing the front and back of a document through a document reversing path. The document reversing unit 30 is provided with conveyance roller groups 31, 32, 33, a guide plate 34, and a document passage detection sensor PS5 for detecting a document passing through the reversing unit 30.

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

M is a servo motor in which a DC motor and a speed control device (encoder, tachogenerator, or the like) are integrated. A toothed pulley P1 integral with the drive shaft 20 of the servomotor M,
A toothed belt B1 is stretched between the pulleys having a toothed pulley P2 fixed to the intermediate shaft 21, and the intermediate shaft 21 is rotated by the drive 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 toothed belt B2 is provided between the pulley P3 and the pulley P5 fixed to the shaft end of the transport belt driving roller 9.
Are wound and meshed 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 in which power is transmitted by the servomotor M. Next, the operation of the drive system will be described. FIG. 7 is a diagram showing the rotation speed of each sheet feeding roller by the drive system, FIG. 8 is a block diagram of the drive system, FIG. 9 is a flowchart, and FIG. 10 is a time chart.

When a stack of documents is stacked on the document table 1 and abutted against the stopper 1D, the document set detection sensor PS2 detects the presence or absence of the document and the ADF mode is set.

When the lateral width regulating plates 1A, 1A are moved to touch the lateral side edges of the bundle of originals, the original size detection sensor PS1 detects the original lateral width, and the CPU converts and stores the original length.

When the copy button 111 is pressed, a copy start signal is input, and the pickup roller 2 descends to press the uppermost layer of the original stack.

When the motor M continues to drive, the motor drive shaft 20
The upper toothed pulley P1 rotates to rotate the intermediate shaft 21 having the toothed pulley P1 via the toothed belt B1. At this time, both electromagnetic clutches (MC) K1 and K2 are in the ON state,
The feed roller shaft 22 is driven and rotated by the rotation of the toothed belt B3, the feed belt 3 is rotated through the gears G1, G2, and the feed roller 3A, and the pickup roller 2 is also rotated by the toothed belt B4. At the same time, the toothed pulley P7 that meshes with the toothed belt B3 is also rotated, and the intermediate conveying roller shaft
The intermediate conveying roller shaft 5 is rotated by rotating 23.

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 transfer roller 5, and the transfer belt 8 are all in the high speed transfer mode v ₁ (for example, 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 of the upper original bundle is sent out by the pickup roller 2, and is separated by the feed belt 3 and the double feed prevention roller 4, and the uppermost one original passes through the intermediate conveying roller 5 and the guide plate 6. It is conveyed, and then it is squeezed by the conveyance belt 8 in a rotating state and slides on the platen glass 101, and the motor M is turned off and stopped before the position where the leading edge of the original abuts the original stopper 102. Apply the brake and hit the stopper with inertial force. In this embodiment, the motor is turned off about 5 to 10 mm before the stopper.

In the stationary state of the original document in the image exposure unit, scanning exposure is started by the optical system on the copying machine main body side. At this time, before or during the scanning exposure, the next original is sent out and fed through the feed roller 3 and the intermediate conveyance roller 5, and when the leading edge of the original passes the original notification detection sensor PS3, a detection signal is emitted and a timer is used. This document is stopped at a predetermined position and made to stand by by the time t (or the pulse count by the counter). During this time, since the electromagnetic clutch K2 for feeding is ON, the conveying electromagnetic clutch K1 is set to OFF, the preceding document in the exposure has been stopped, the subsequent document is fed in the low-speed feed mode v ₂ during this time Then, the leading end reaches the vicinity of the platen glass 101 and stands by. However, the operation during this period is at least after the scanning is completed.
The speed of v ₂ (for example, v ₂ = 500 mm / sec) is determined to be completed 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. 11 is a plan view showing a stopped state of documents (B5 to A3) of various sizes placed on the platen glass 101 and abutted against the document stopper 102.

In the embodiment of the present invention, the four types of document sizes are roughly classified into two types, that is, a small size document of B5 size and A4 size, and a large size document of B4 size and A3 size.

FIG. 6 (B) is a schematic diagram showing the paper feeding / conveying process of the small size original document (B5, A4) D1. When the document size is detected by the document size detection sensor PS1 by the operation of the lateral width regulating plates 1A, 1A, it is determined as the small size document D1 by the processing of this detection signal. The timer t starts when the leading edge of the subsequent small document D1 passes the document passage detection sensor PS3.
When the time counting by 3 is started and the set timing corresponding to the small-sized document D1 is finished, the motor M is temporarily stopped and the leading end of the document D1 is stopped at the P position shown in the figure. The document transport speed v ₂ during the feeding time t3 is lower than the transport speed v ₁ of the preceding document on the platen glass 101 (for example, v ₁ = 1200 mm / s).
ec, v ₂ = 500 mm / sec). Since the leading end of the document D1 at the temporary stop position P is a position near the document table glass 101 and not pressed against the conveyor belt 8, it is close to the trailing end of the preceding document by a short distance.

Next, at the end of the scanning exposure, the main motor is turned on and the electromagnetic clutch K1 for conveyance is turned on, so that the preceding document is conveyed by the conveyor belt 8 and ejected onto the ejection tray 14 via the ejection rollers 13.・ Placed. At the same time, the succeeding document is nipped and slid from the standby position on the platen glass 101, reaches the document stopper 102 by the stopping operation, and the document replacement is completed. At this time, the document transportation by the timer t4 is the high-speed transportation mode v ₁ .

Next, FIG. 6 (C) shows a paper feeding / conveying process of the large-sized document (B4, A3) D2. When the leading edge of the subsequent large-sized document D2 passes the document passage detection sensor PS3, the timer t7 starts timing, and when the set timing corresponding to the large-sized document D2 ends, the motor M pauses and
The tip of D1 is stopped at the Q position shown. This delivery time
The document conveyance speed during t7 is v ₁ . Also, the feeding time t
Since 7 is set smaller than the feeding time t3 of the small-sized document D1, the document stop position Q is a position close to the intermediate conveyance roller 5. A predetermined interval is maintained between the leading end of the subsequent document D2 at the stop position and the trailing end of the preceding document placed on the document table glass 101 and in contact with the document stopper 102.

According to the automatic document feeder of the present invention, even if the document size is different, the leading edge of the following document approaches the trailing edge of the preceding document, and the leading edge of the following document preliminarily reaches the minimum required interval. At the same time that the preceding document is discharged to the discharge tray, the following document is restarted from the temporary stop position P or Q, and the document conveying distance for following and conveying is short, so that the document exchange time can be shortened. It is possible. This improves the continuous copying speed (the number of copies per minute).

Further, since the document conveying speed v _{2 at} the preceding forward distance of the succeeding document can be set independently of the conveying speed v ₁ of the preceding document, by setting the speed v ₂ low, the feed roller The separation by 3 and the double-feed prevention roller 4 can improve the separation performance by low-speed handling. Moreover, the stop position accuracy is improved by reducing the speed.

When the first sheet feeding slow v ₂ is even sensor PS3, it is clear that a similar effect on 1 sheet if the conveyance thereafter v _1.

Further, the start of re-conveyance for discharging a document from the stop position of the document stopper 102 and the double feed prevention process at the start of document feeding are not simultaneously turned on, so that the load on the motor is reduced and the power consumption is reduced. It is possible to save labor and install a low torque motor.

Further, the document nip of the intermediate conveying roller 5 and the subsequent document U-turn by the guide plate 6 are smoothly performed by the document low-speed feeding, and the document front end is less damaged.

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 copying a two-sided original, when the original is fed back to the original reversing unit 30 and inverted and conveyed again to the original platen glass, timing is started from the detection of passage of the reverse original passage detection sensor PS5 and the same as above. The same effect can be obtained by setting the temporary stop positions for the size document and the small size document respectively.

〔The invention's effect〕

As described above, according to the automatic document feeder of the present invention, not only the document feeding time can be shortened, but also the separation performance is improved and the document feeding is smoothed due to the low speed handling at the time of feeding the document. It is effective to prevent damage to the document and damage to the leading edge of the document.
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.

[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 sheet feeding roller by the drive system, FIG. 8 is a block diagram of the drive system, FIG. 9 is a flowchart of the document feeding and conveying process, FIG. 10 is its time chart, and FIG. FIG. 11 is a plan view showing a stationary state of various document sizes. 1 ... Original platen, 1A ... Width control plate 1B ... Pinion gear, 1C ... Rack gear 2 ... Pickup roller 3 ... Feed belt, 3A ... Feed roller 4 ... Double feed prevention roller, 5 ... … Intermediate conveyor roller 6 …… Guide plate, 8 …… Conveyor belt 9 …… Conveyor belt drive roller 13 …… Paper ejection roller, 14 …… Paper ejection tray 20 …… Motor drive shaft, 21 …… Intermediate shaft 22 …… Feed roller shaft, 23 …… Intermediate conveyance roller shaft 30 …… Original reversing part, 31,32,33 …… Conveying roller group 34 …… Guide plate 101 …… Image exposure part (Platen glass) 102 …… Document stopper 110 ...... Control panel 111 …… Copy button B1, B2, B3, B4, B5 …… Toothed belt P1, P2, P3, P4, P5, P6, P7, P8, P9, P10, P11 …… Toothed pulley K1 , K2 …… Electromagnetic clutch (MC) M …… Servomotor, D …… Original D1 …… Small size original (B5, A4) D2 …… Large size original (B4, A3) PS1 ... document size detection sensor PS2 ...... document set detection sensor PS3 ...... document passing detection sensor PS4 ...... document discharge sensor PS5 ...... inverted document passing detection sensor v ₁ ...... fast transport mode, v ₂ ...... low speed feed mode

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masanobu Kono 2970 Ishikawa-cho, Hachioji-shi, Tokyo Konica Corporation Toshio Kanata (56) Reference JP-A-61-32836 (JP, A) JP-A-SHO 64-17734 (JP, A) JP-A-1-236136 (JP, A)

Claims (3)

(57) [Claims] 1. A plurality of sheet-shaped originals are sequentially conveyed to an image exposure unit, the originals are stopped at the image exposure unit, an optical system is moved to perform scanning exposure, and the originals are discharged after the exposure. In the automatic document feeder that carries out the document to the table, the detection unit that detects the document size by the moving position of the lateral width regulation plates on both sides of the document on the document table, and the sheet-form that follows before the exposure operation of the preceding sheet-form document is completed. A registration roller that starts feeding the original, a detection sensor that detects the passage of the subsequent sheet original, and a sheet original that is being conveyed after a predetermined time has elapsed based on the detection sensor signal And a stop means for temporarily stopping the sheet in the conveying path before inserting the sheet between the exposure position and the discharge position of the preceding document sheet from the exposure position. Serial automatic document feeder being characterized in that variably set a temporary stop position of the subsequent document. 2. A temporary stop position of a succeeding original according to the original size is set at least at two positions between the original placing table and the original table glass, and the front end of the subsequent original and the rear end of the preceding original which are temporarily stopped. 2. The automatic document feeder according to claim 1, wherein the temporary stop position is set by changing the distance on the transport path between and according to the document size. 3. The document feeding operation speed for feeding from the registration rollers of the document placing table to the temporary stop position is equal to or lower than a document feeding speed on the image exposure section. Automatic document feeder.