JPS60260032A - Automatic original feed device - Google Patents

Abstract

PURPOSE:To prevent a double feed by comparing the length of a carried original in an inlet and an outlet of the original, detecting a double feed of the original, and separating the original by applying a brake to a discharge paper roller of a driven side. CONSTITUTION:A carried original length LSER at a position of a resist sensor SER measured by a measuring means 71 is stored in a memory 72. Also, a measuring means 75 measures a carried original length LSEE at a position of a discharge sensor SEE, both of them are compared, and in case when the carried original length LSEE is longer than the carried original length LSER, it is decided that the original has been fed doubly, and a double feed signal is outputted to a display means 74, and motors M1, M2 are stopped. When the tip of the original passes through the discharge sensor SEE, the length of the original is measured every moment as a count value of a pulse sensor PSR by the measuring means 75. A count value BONCOU for driving a brake BL and a count value BOFFCOU for releasing it are set in advance to a setting means 76. A comparing and deciding means 77 inputs the count value from the measuring means 75, and when it is decided that said value is larger than the count value BONCOU, and smaller than the count value BOFFCOU, a driving signal is outputted to the brake BL, a discharge paper roller 45 is fixed, and the double feed original is separated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to an automatic document feeder used in electrophotographic copying machines, facsimile machines, etc.

[Prior art] When copying a sheet original consisting of many pages using an electrophotographic copying machine, the original is placed one by one on a contact glass, a pressure plate is set, and after exposure, it is removed and replaced with the next original. This is extremely troublesome, so in order to save this labor, the originals placed in the original tray are automatically fed one by one to the exposure unit, and the exposed originals are automatically ejected. Automatic document feeders have come into use.

When making multiple copies from a series of sheet originals consisting of many pages, generally one sheet of the original is placed once on the contact glass and then the same number of copies as the number of copies to be made are made consecutively. Normally, this is repeated for the number of original sheets, and the copies ejected from the copying machine are collected and collated using a sorting machine such as a rurui or sorter to make the required number of copies with the same page order. With the above-mentioned automatic document feeder, the time required to feed a document from the document tray to the exposure section is short and can be almost the same as the return time of the scanner. By copying one page each time a series of originals is sent, and repeating the same operation the same number of times as the number of copies to be made, the required number of copies with the same page order can be obtained and the collation work can be simplified. No longer needed.

In this case, the automatic document feeder feeds the documents placed in the document tray one by one from the top or bottom to the exposure section.
By returning the exposed original onto the group of originals in the original tray, it is possible to make the required number of copies by continuously and repeatedly circulating the original a number of times equal to the required number of copies.

If the sheet original is thick to some extent and has no folds or bends, it will be fed one by one, but if the sheet original is thin, close together, or has a fold in the middle, multiple sheet originals may be fed. There is a risk of overlapping and multi-feeding. However, in the past, there was no way to detect double feeding of originals, so
In order to prevent the serious problem of page skipping due to double feeding, it was necessary to perform the extra work of comparing and checking the original and the copy after all copying was completed.

Furthermore, when a conventional automatic document feeder is used in a facsimile machine, there is a risk that a serious problem may arise in which the document is sent without skipping pages.

〔the purpose〕

The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide an automatic document feeder that can detect double feeding of documents.

[Example〕 Hereinafter, the present invention will be explained based on an illustrated embodiment.

FIG. 1 shows a copying machine embodying the present invention. The schematic configuration of the apparatus will be explained with reference to FIG. 1 is a contact glass on which the original is placed. An optical scanning system is provided below the contact glass 1, and an image of light reflected from the original is formed on the photosensitive drum 3 via this optical scanning system. The photosensitive drum 3 rotates clockwise in FIG.

The paper feed system has two stages, and recording paper is fed from a selected one of paper feed cassettes 4 and 5 by paper feed rollers 6 and 7. The fed paper passes between the registration roller 8 and the near-tip bending roller 9 and reaches the photoreceptor drum 3.
be guided by. Around the photosensitive drum 3, there are a charger 10, an eraser 11, a developing device 12, a pre-transfer static elimination lamp & P sensor 13, a transfer charger 14, a separation charger 15, a separation claw 16, a fur brush 17, and a static elimination lamp 1.
8th grade is placed.

To explain the copying process, the photosensitive drum 3 is charged to a uniform potential by the charging charger 10, and when it is irradiated with reflected light from the original, the surface potential changes depending on the light intensity, and this causes static electricity. A latent image is formed. This electrostatic latent image is made visible by toner when it passes through the developer 12. The fed recording paper is sent by the registration roller 8 at a predetermined timing according to the rotation of the photosensitive drum 30.
This toner image overlaps the surface of the photoreceptor drum 30 on which it is formed.

After this, a predetermined voltage is applied to the transfer charger 14,
As a result, the toner image is transferred from the photosensitive drum 3 to the recording paper side. Furthermore, the recording paper onto which the toner image has been transferred is separated from the photosensitive drum 3 by the separation charger 15 and directed toward the conveyance bell H9. Then, the recording paper passes through a fixing roller 20 having a built-in heater to fix the toner image thereon, and then heads to a copy tray 22 via a paper ejection roller 21.

An automatic document feeder (ADF) is located above the contact glass l. This device includes a separating device 30 that separates and feeds original documents on a document table one by one, and a conveying device 31.
2a, 2b, and 2c show details of the automatic document feeders 30 and 31 shown in FIG. 1. The separating device 30 and the conveying device 31 are equipped with independent motors M1 and M2, respectively. Motor Ml is an AC motor, and M2 is a DC servo motor. First, to explain the separation device 30, a disk DK for position detection, a drive pulley 47, and a pull-out roller 32 are connected to the drive shaft of the AC motor M1. There is. Disk D
K has many slits formed at equal intervals around the periphery, and a transmission type pulse sensor P8 is placed at a position facing the slits.
R is fixed.

As the disk DK rotates, the nozzle sensor P
Slits and non-slit parts alternately face each other in the EH, and the light from the pulse sensor PAH is intermittently blocked, resulting in a pulse signal pulse sensor PB corresponding to the amount of rotation of the disk DK.
The output terminal of H is obtained.

A driven roller 33 is in light contact with the pull-out row 232. Drive pulleys 48 and 49 are connected to the drive pulley 47 via a drive bell (BE).

Separation ports 35 and 34 are connected to drive pulleys 48 and 49 via electromagnetic clutches OLL and O, LU, respectively. Shaft 3 of upper separation roller 34
4a is connected to a drive pulley 954, and the drive pulley 53 is connected to this pulley 54 via a drive bell (BFi2). The drive pulley 53 is coupled to the calling roller 36.

The shirt 36a of the calling L roller 36 has support members 51 and 52 that are rotatable around Pl and P2, respectively.
compression coil springs 8Pl and s, which are normally coupled to support members 51 and 52, respectively.
It is held in an upwardly pulled state at p2. In this state, the calling roller 36 is separated from the document sheet 38 on the document table 37 as shown by the solid line in FIG. 2a, but when the solenoid SLO connected to the support member 51 is energized,
The calling roller 36 is pulled down and comes into contact with the original sheet 38.

The operation of the separation device 30 will be explained. When a document is set, the motor M1 is first driven, the solenoid SL○ is energized, the calling roller 36 is brought into contact with the document sheet 38, and the upper clutch OIL+U is energized.This causes the document sheet 38 to be called. , the uppermost one is separated and sent between the separating rollers 34 and 35, and is then sent to the pull-out roller 3.
2 and 33 and is discharged from the separation device 30.

In BADF mode, in which originals are set one by one, the clutch (3111J) is turned on and the lower separation roller 3
5 is also driven. s]l! IS and 81R are reflective photosensors, and function as a set switch that detects whether a document has been set on the document table 37, and a registration sensor that detects whether a document is at a predetermined position.

A rotary encoder P8B is coupled to a DC servo motor M2 that is a drive source of the conveyance device 31. This encoder PSB outputs a pulse signal every predetermined operation of the motor. This pulse signal is a two-phase pulse signal of A phase and B phase that are shifted from each other by a predetermined phase. The drive shaft of the DC servo motor M2 includes a drive pulley 56 and a drive bell) BH.
3 and a drive pulley 55 to the belt roller 41 . A guide plate 46 and paper ejection rollers 42, 43, 44, and 45 are provided on the downstream side of the transport device 31, and the exposed original sheet is transported along the guide plate 46, reversed, and delivered to the paper ejection tray. (not shown). sF! Denoted by m is a reflective photosensor, and the guide plate 46 functions as a paper discharge sensor for detecting the presence or absence of a document sheet.

The paper ejection rollers 42 , 43 , 44 , and 45 each form a pair, and in this embodiment, the paper ejection rollers 44 ; 45
The paper ejection roller 44 is a driving roller to which a motor (not shown) is connected. The paper discharge roller 45 is a driven roller and is provided with a brake BL for document separation. The operation of separating double-fed originals by the discharge rollers 44 and 45 will be explained with reference to FIG. 2d. Figure 2d shows the discharge sensor 5F3
Only the area around E and the paper ejection rollers 44 and 45 are shown.

When the original Sa and the original sheet are conveyed in an overlapping state and pass through the ejection sensor 8FiB, and the leading edge of the original enters the ejection rollers 44 and 45 (Fig. 2d (11) the driven side ejection roller 45
The brake BL of is driven to stop the rotation (82(1)
Figure 12)). Then, only the upper original document a is fed, and the lower original document a remains stopped (Fig. 2d (3)). After a predetermined period of time has elapsed, the brake BL applied to the driven paper discharge roller 45 is released. Then, the document on the lower side is also fed (C4 in Fig. 2d)). In this way, double-fed documents can be separated by applying the brake BL to the driven side paper ejection roller 45 for a predetermined period of time.In addition, a torque limiter (not shown) is attached to the driven side paper ejection roller 45 together with the brake BL. ) may be provided. The torque limiter is designed to rotate the roller t5 when a load greater than a predetermined load is applied to the roller. This can prevent documents that are not double-fed from being damaged by this double-fed document separation operation. The predetermined load of the torque limiter is selected to be greater than the friction between the documents and smaller than the friction between the documents and the roller.

In this example, the exposure position is based on the left end in FIG. 2a, and the original sheet fed from the original platen 37 is
As will be described later, the document is positioned such that its leading edge in the traveling direction always stops at a predetermined position (specifically, near the belt roller 41) regardless of the size of the document.

Next, the control of the automatic document feeder according to this embodiment will be explained with reference to the block diagram of FIG. 2a and the flowcharts of FIGS. 3 to 8.

As shown in Figure iZa, the motor Ml that drives the pull-out roller 32 includes a disk DK for position detection and a pulse sensor P8R that detects the slit of the disk DK.
is provided. The measuring means 71 uses this pulse sensor PAR,! :, input the output signal of the registration sensor 8EH, and calculate the document length LE at the position of the registration sensor 8BH.
It measures lPR, and counts the number of pulses from the pulse sensor PsR while the registration sensor SZR is on, as shown in FIG. In addition, in reality, the pulse sensor PSH
Since it detects the rise of the resist sensor S]1n
It should be noted that even if the on-times are almost the same, the count value may deviate by two pulses as shown in FIG.

The document length LAIR measured by the measuring means 71 at the position of the registration sensor SBH is stored in the memory 72 . Further, the measuring means 75 inputs the output signals of the pulse sensor PSR and the discharge sensor 8EtIIi, and receives the output signals of the discharge sensor 81
Document length L81 at DB position! Measure iFf.

The transported document length LSIIIB measured by the measuring means 75 is:
The registration sensor SF! stored in the memory 72 by the comparison and determination means 73! Document length L+82 at position H!
Compared to iR. If the transported original length L8BIIl is longer than the transported original length L8BR, it is determined that the originals have been fed in duplicate. This is because when documents are fed in duplicate, the documents are separated by the discharge rollers 44 and 45, so that the length of the document to be conveyed L8mIif becomes longer. When it is determined that double feeding has occurred, a double feed signal is output to the display means 74 to indicate that double feeding has occurred, and the motor M1. Stop M2.

Control of the brake BL for separating double-feed documents will be explained.

When the leading edge of the document passes the ejection sensor 8BFf, the measuring means 75 detects the ejection sensor 8I! The length of the document that has passed through i1 is measured every moment as a count value of the pulse sensor PER. A predetermined count value BONOOU for driving the brake BL and a predetermined count value BOPPOOU for releasing the brake BL are preset in the setting means 76. The comparison/judgment means 77 inputs the count value from the measurement means 75 and determines that the count value is a predetermined count value BONOO.
If it is determined that the count value is larger than U and smaller than the predetermined count value BOFFOOU, a drive signal is output to the brake BL.

As a result, the paper discharge roller 45 is fixed and the double-fed documents are separated.

Next, more detailed control operations will be explained with reference to FIGS. 3 to 8. Figure 3 is a schematic flowchart, and Figures 4 to 8 are steps O, D, F, G.
This is a detailed flowchart of 0. After the power is turned on, initial settings are first made in step A. Initial setting refers to the operation of setting each device to its initial state for future control operations, such as setting the input/output board such as setting the solenoid to the non-suction state or turning off the LFiD, and clearing the RAM. And so on.

Next, in step B, an input check is performed. This is set sensor SMS, resist sensor 8FliR.

Various modes of each sensor and each switch, such as the discharge sensor sHE, are checked.

Next, in step O, a start check is performed. The start check checks whether to start copying. As shown in FIG. 4, first, in step 301, it is checked whether the print switch is turned on. If the print switch is turned on by the operator, it is checked whether the original set switch 81!1T8W is turned on (step 302). Original set switch 81!
1TEIW is turned on and off when the set sensor 8ES detects whether or not a document is set on the document table 37. When the original is set on the original platen 37, it is checked whether the copy flag 0OPF is "1" (step 303). Copy flag 0O
PF being "1" means that copying is currently in progress. When the copy flag 00PF is "0", the copying operation is started, rlJ is set in the copy flag 0OPF, the motor Ml is started, the paper feed solenoid is turned on, and the document count register B is turned on. (step 304). Note that if the print switch is off or the document set switch 8BT8W is off,
If copy flag 0OPF is rlJ, step 3
Proceed to the next step D without executing step 04.

Next, in step D, register sensor S]l! ! Check H. As shown in FIG. 5, check whether the head registration sensor 8FiR is on (step 40).
1). When the leading edge of the document reaches the position of the registration sensor BBR, the process moves to step 402, where it is determined whether the registration sensor flag 5ER1I' is "1" or not. The fact that the registration sensor flag 81!1RII' is rlJ indicates that the document has been conveyed, and if the registration sensor flag 811iRF is "0", r
Set lJ and register A for document length count.
is set to "0" (step 403). -7 If the registration sensor 5FIR is off, the process moves to step 404 and the registration sensor flag 81! Check whether IRF is "1". Resist sensor flag 81! iRF is “1”
", set the registration sensor flag 8FIRIF' to "0" in step 405, and then
6, the value of the document length count register A is entered into the original counter oRGaoty. Therefore, the original counter 0R()0017 is the register sensor SHH
Document length L at position L EIII! It will be raining on R.

Next, in step E, the discharge sensor BIB is checked. As shown in FIG. 6, first, it is checked whether the discharge sensor 5BFi is on or not (step 501). When the original reaches the position of the ejection sensor 8BB, the process moves to step 502, and it is checked whether the ejection sensor flag 8ItilliF is "1". If the discharge sensor flag 81!1FiF is not "l", in step 503, the discharge sensor flag simy is set to "1", and the document count register B is incremented by a count of "1". Further, in step 503, the document count register ○ is cleared. The document count register C is a sensor for measuring the length of the transported document at the position of the discharge sensor sum. Next, register C for document count.
When it is determined that is larger than the brake drive count value BONOOU and smaller than the brake release count value BOFFOOU (step 504, sos), the brake BL is turned on (step 506). In other cases, the brake BL is turned off (step 507). This makes it possible to separate double-fed originals.0 Ejection sensor 81! If iFf is not on, it is checked whether copy flag 0OPF is [IJ] (step 504). If the copy flag C0PF is Ill, it indicates that copying is currently in progress. If copying is in progress, check whether the ejection sensor flag 8EBF is "1" (step 509) - Ejection sensor flag BBE
If F is "1", the discharge sensor flag 8FfBF is set to "0" in step 510, and the value obtained by subtracting 2 from the document count register O is set as the original counter 0RG.
OOU.

It is determined whether the value is larger than the value (step SO).

If the document size is too large, the documents may be fed multiple times and the paper ejection roller 44°4
5 means that it has been separated by 5, so step 51
3, the zip is stopped, and each motor Ml, M2
to stop the transport. At the same time, a double feed signal is output to indicate that there is a double feed.

If the value obtained by subtracting 2 from the original count register C is less than the value of the original counter 0RGOOU, it is checked whether the original set switch 5BT8W is on (step 511). If the document set switch 5BTSW is off, the conveyance of the document has already been completed, so in step 512, the value of the document count register B is set to the discharge sensor counter date FtFIOOU, and the process proceeds to the next step F. Note that in step 511, the document count register 0 is
The reason why 2 was subtracted from is that the count value may deviate depending on the timing when the discharge sensor date KFt is turned on or off.

Next, in step F, the pulse sensor PBR is checked. As shown in FIG. 7, first, it is checked whether the pulse sensor PSR is on or not (step 601). If pulse sensor PAR is off, pulse sensor flag P
rl) Jt-set to 8RF (Stella 7'602)
. If the pulse sensor PSR is on, check whether the pulse sensor flag P8RF is "1" (step 6).
03), if it is not rlJ, pulse sensor flag PSR
After setting Ill to F (step 604),
Step 605) increments the document length count registers A and O by one (step 605), and proceeds to the next step G.

Next, in step G, jam checking and processing are performed. Here, the registration sensor 5IR detects whether or not there is a jam.
1 discharge sensor sI! Check whether the registration sensor 8ER is turned on at a predetermined timing (y). As shown in FIG. It is checked whether it is the timing of the registration sensor SI (step 702).
Since R should be turned on, this predetermined timing can be determined. If the registration sensor SBR is on but not at the predetermined timing, a jam is displayed and the motors M1 and M2 are stopped (step 705), and the jam is checked and processed. Similarly, in step 703, the discharge sensor SBB
Check whether it is on or not, and if it is, check whether it is at a predetermined timing (step 7).
04).

The predetermined timing of the discharge sensor sum is also determined in advance in the same manner as the registration sensors 8E and 8R.

Next, in step H, transmitted and received data is checked. Transmission/reception data check is a process of checking data transmitted/received with the copying machine main body.Next, data is output in step E. For example, the data set by the previous processing is output to the solenoid, motor, display, etc., and the solenoid is actually turned on/off, the motor is turned on/off, and a predetermined display is made on the display.

A specific example of an electric circuit that realizes the above processing is shown in FIG. A copying process control unit 2000, that is, a control unit of the main body of the multi-purpose machine, is connected to the automatic document feed control unit 1000. Control unit 2 on the main body side
000 is an automatic document feed control unit when a copy start instruction is given. 1000 is a serial signal transmission line (
A paper feed instruction signal is output via RXDo, 1), and when a predetermined copy cycle is completed, a paper discharge instruction signal is output to the control unit 1000 via a serial signal transmission line.

The control unit) 1000 includes the aforementioned AC motor M1,
DC servo motor M2, clutch OLU, OLL.

The solenoid 5L01 set switch SGS, paper discharge sensor SKB, registration sensor 8KR, rotary encoders PSR, P8B, etc. are connected.

Furthermore, the brake solenoid that drives the brake BL is also connected to the control unit) 1000.

The switches aS and os2 are respectively connected to the separation device 3.
DSPU is a 7-segment display that displays the number of original sheets, and LEDU and LIITPB are light emitting diode units that display the operating status of the device.
, sw2.8W3.8W4 and 8W5 are switches for setting various operation modes.

In this embodiment, the length of the transported document is measured at two locations for each document being transported, and the measured values are compared.
Double feeding of originals can be detected even if the sizes of the transported originals are different. Therefore, originals of various sizes can be set at one time and automatically conveyed.

In the previous embodiment, the length of the conveyed document is measured by the disk DK and pulse sensor P8H provided on the motor M1.
Although predetermined timings for the registration sensor date FfR and the discharge sensor 8FfE have been determined, if the transport speed is known in advance, a timer may be used instead.

Also, when comparing the transported original length LSKR and the transported original length LSFIM, the transported original length LSF! Although 2 counts were subtracted from the original counter 0RGOOU indicating R, it is not necessary to subtract 2 counts. Furthermore, resist sensor 8
The positions of the BR and the exhaust sensor 8EE do not necessarily have to be the positions shown in FIG. 2a.

Furthermore, the means for separating double-fed documents may be provided at any position downstream of the registration sensor 8BR. In addition, a measuring sensor may be provided separately to determine the length of the conveyed document7. Various other modifications are possible within the scope of the present invention.

The automatic document feeder of the present invention can be applied not only to document feeding in a copying machine but also to facsimile document feeding, main body paper feeding in a copying machine, and automatic sheet feeding in a printer.

[Effects] As described above, according to the present invention, double feeding of documents can be reliably detected, and page skipping can be prevented in advance. Therefore, in the case of a copying machine, there is no need to perform the extra work of checking the original and the copy again, and the work efficiency can be improved.

[Brief explanation of drawings]

FIG. 1 is a structural diagram of a copying machine having an automatic document feeder according to the present invention. FIGS. 2a, 2b, 2C, and 2d are detailed structural diagrams of an automatic document feeder according to the present invention. 3 to 9 are diagrams showing the operation of the automatic document feeder, and FIG. 10 is a diagram showing a specific example of an electric circuit for controlling the automatic document feeder. ■... Contact glass, 3... Photosensitive drum, 4
゜5...Paper feed cassette, 6,7...Paper feed roller, 8.
...Register roller, 9...Roller, 1O...Charger, 11...Eraser, 12...Developer,
13... Transfer agent static elimination lamp & P sensor, 14... Transfer charger, 15... Separation charger, 16...
Separation claw, 17... Fur brush, 18... Static elimination lamp, 19... Conveyance belt, 20... Fixing roller, 2
1... Paper ejection roller, 22... Copy tray, 3o.
... Separation device, 31... Conveyance device, 32... Pull-out roller, 33... Followed roller, 34, 35...
・Separation roller, 36... Calling roller, 37... Original table, tapping... Original sheet, 39... Conveyance belt, 41.
・・Belt roller, 42 , 43 , 44 , 45 ・・
- Paper discharge roller, 46... Guide breaker, 47, 48
, 49... Drive pulley, 51, 52... Support member, 53, 54... Drive boo 1 Huff 1, 75...
Measuring means, 72... Memory, 73, 77... Comparing and determining means, 74... Display means, 76... Setting means,
ADF...Automatic document feeder, Ml, M2...Motor, DK...Disk, PAR...Pulse sensor,
OLL, OLU...1iL magnetic gratch, sLe...
・Solenoid, 8BR...Registration sensor, EIBF
i...Emission sensor, PSB...Rotary encoder. Applicant's representative Inomata Seidou Figure 1 Figure A Figure 2B Figure 2C Figure Liu Figure 8■ Jaw

Claims (1)

[Scope of Claims] 1. Conveying means for conveying original documents one by one so as to pass through an exposure section; a first detection means provided on the conveyance path and detecting the presence of the conveyed original; a first measuring means for measuring the length of the conveyed document during conveyance by the first detecting means; and a first measuring means provided at a position downstream from the first detecting means on the conveyance path to detect the presence of the document being conveyed. 2nd to detect
a second measuring means for measuring the length of the conveyed document during conveyance by the second detecting means; and a second measuring means provided at a downstream position from the first detecting means, the second measuring means is provided at a position downstream from the first detecting means, and is configured to detect double-fed documents along the conveyance path. comparing the length of the second conveyed document measured by the second measuring means with the first length of the conveyed document measured by the first measuring means; and a comparative determination means for determining that the document has been double fed when the length of the document is larger than the length of the document to be conveyed, and stopping the conveyance of the document when the comparison and determination means determines that the document has been double fed. An automatic document feeder characterized by: 2. In the apparatus according to claim 1, the measuring means measures the passing time by counting pulses of a pulse encoder provided in a portion of the conveying means driven by a drive motor. Characteristic automatic document feeder. 3.t# The automatic document feeder according to claim 1, wherein the measuring means is a timer. 4. In the apparatus according to any one of claims 1 to 3, the separating means separates the original by applying a brake to a driven roller of a pair of transport rollers that transport the original. An automatic document feeder characterized by: 5. An automatic document feeder according to claim 4, characterized in that the driven roller is provided with a torque limiter.