JPH06298404A - Paper sheet feeder - Google Patents

Abstract

PURPOSE:To detect multifeed of documents immediately after the occurrence of the multifeed so as to facilitate recovery at the time of conducting image reading action or image forming action. CONSTITUTION:An automatic paper feed is adapted to separate and feed a document O by a separation member 26 and a paper feed roller 31 and so constructed that a detecting member 33 having pressure sensitive conductive rubber 33a is provided downstream from the separation member 26, and according to the detection of the detecting member 33, the change of thickness of a document O is converted to an electric signal so as to detect the transport condition of documents O such as skew, multifeed and the like.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art Conventionally, there is a known example of an automatic sheet feeder (sheet feeder) using a pressure sensitive sensor.

An example thereof is Japanese Patent Laid-Open No. 63-117823. In this system, a pressure sensor is attached to the paper guide of the document feed table to detect that the side surface of the paper comes into contact with the guide. The purpose of this known example is to solve the problem that the document guide must be set again after being aligned with the document. That is, the document guide is automatically set.

Another known example is JP-A-63-28156.
No. 9 publication. The purpose of this is to detect the pressure applied to the take-out roller at the paper take-out portion with a pressure sensor and adjust the pressure applied to the take-out roller. By this pressure adjustment, the paper can be taken out stably.

Further, as a known example for detecting the thickness of the paper being fed, there is JP-A-2-127327. It detects the displacement of the paper feed roller. In this embodiment, a non-contact micro displacement sensor (for example, a laser displacement sensor manufactured by Keyence Corporation) is used. There is no.

Further, the purpose of detecting the thickness of the paper is to reliably convey the paper by adjusting the pressing force of the pressure roller in the paper feeding section for reversing the original according to the thickness of the paper.

Japanese Laid-Open Patent Publication No. 4-52780 describes an embodiment in which double feeding of sheets is detected, separate output destinations for double fed documents and other documents are provided, and only double fed documents are extracted. There is.

In this embodiment, two types of double feed detection methods are described.

The displacement of bearings of a pair of rollers for feeding a sheet is read by an optical displacement sensor.

Another method is to detect the thickness of a document being conveyed by using a capacitance sensor.

Further, a plurality of originals are once input to a document reading device, standard deviations and variances of the thickness and length of the target document are calculated, and double feeding is detected based on the values.

Japanese Unexamined Patent Publication No. 3-107174 discloses an automatic document feeder for feeding a document to a copying machine, and counts and displays copied documents based on a detection signal from a paper discharge sensor of the automatic document feeder. Examples have been described.

However, in the first known example, the pressure sensitive sensor is used only for turning on and off, and the automatic setting of the document guide is only realized. Moreover, there is no specific description of the pressure-sensitive sensor.

Further, in the second known example, the pressing force is only adjusted in order to ensure the stability of taking out the paper. Further, like the first known example, there is no specific description of the pressure sensitive sensor. Similarly, in the third known example, the pressing force is merely adjusted in order to improve the reliability of the paper conveyance. Further, the means for measuring / detecting the displacement of the transport roller is expensive and impractical.

In the fourth known example, the displacement sensor
The method of detecting the displacement amount of the conveyed roller has the following problems.

In this embodiment, the resolution of the displacement sensor is 1
Although it is described as about 10 μm, such a displacement sensor is very expensive, and since the accuracy of the outer diameter of the roller that conveys the sheet is 5 to 10 μm, the displacement of the sheet is Before the reading, there is a problem that the displacement data is largely shaken and it becomes difficult to detect the actual double feed.

In the means for detecting the thickness of the original using the electrostatic capacity sensor, even if the same original is detected even if the electrostatic capacity of the conveyed sheet is low or the humidity is high, There is a problem that the result of the detection of the difference is different. In the worst case, a leak may occur between the terminals that detect the capacitance, and the detection circuit may be damaged.

If the original is linear, the thickness will appear as a change in the capacitance accurately, but if the original is curled or between the electrodes of this detection device, Therefore, if the degree of bending of the document is changed, it becomes difficult to accurately detect the thickness. That is, since it is already known that the original document is usually flexible and the bending degree changes during transportation, this method is impractical.

Even if the document is once read for trial and the double feed is detected based on the thickness and length data, if the double feed frequency is different from that at the time of trial reading, the double feed is determined. Error will occur.

In the fifth known example, the number of originals for which copying has been completed is counted and displayed by the paper discharge sensor of the automatic document feeder. In this case, the user, who is the user, must count the number of documents input to the automatic document feeder in advance, compare the count with the displayed count, and detect the double feed by itself. Needless to say, this is a great burden on the user when a large amount of documents are copied or stored in a medium such as communication and an optical disk.

By the way, it is very important to detect the double feeding of the paper in the paper feeding, especially in the apparatus for feeding the original. Automatic paper feeders are used not only in copying machines, but also in facsimiles, optical disk file devices and the like. In a copying machine, when double feeding, it is possible to check the copied paper immediately. However, in this case, the user needs to be on the side until the end of the operation in order to constantly check the operation of the copying machine. In addition, as in recent years, as the speed and capacity of copiers have increased, even if double feed is found, a large number of useless copies are generated before the operation of the copier is stopped.

On the other hand, in a facsimile or an optical disk file device for converting image information of an original into an electric signal, double feeding of the original is a more serious problem. In a facsimile, it is not possible to determine whether or not a multi-feed has been made from the copied paper, and there are few cases in which the lack of information due to a multi-feed is notified by an inquiry from the destination. In this case, it is not only rude to the destination, but the facsimile communication is repeated once again.

In the optical disk file device, when the image information is converted into an electric signal and stored in a storage medium such as an optical disk, in order to confirm whether or not the multi-feed has been made, the information is recalled from the optical disk and a CRT or the like is called. It will be checked by the display means. This significantly impairs the office automation (OA) effect of the optical disk file device that can store a large amount of information.

As described above, the importance of detecting double feed has been recognized, but the means for realizing it have been left undeveloped.

[0025]

By the way, in the conventional automatic paper feeder, when feeding the originals placed on the original feed table one by one, the coefficient of friction between the separation belt and the original is μ _P1 and the friction coefficient between the paper feed roller and the original is
μ _P2 , where μ _PP is the friction coefficient between documents, μ _P2
By satisfying the relation of> μ _P1 > μ _PP , only the document on the bottom surface is fed and the separation function is performed reliably.

However, in reality, there are various originals, and the friction coefficient may differ between the upper surface and the lower surface of the original. In such a case, the condition of the friction coefficient cannot be satisfied, and the documents are fed in duplicate. Further, when the humidity is low, static electricity is generated between the originals, so that the originals stacked may not be separated and may be sent.

When the document thus double-fed is supplied to the image reading device, the information is lost, which causes a paper feeding failure. In the worst case, not only is the document set again in the paper feeding device, but also the document is damaged.

Further, even when supplying to the image forming apparatus,
The following problems occur.

Even when copying a plurality of copies of a plurality of originals, if the originals are double-fed, the pages will be lost, and if a large number of copies are to be made, a large amount of copy paper will be wasted if copying is repeated from the beginning. Become.

In the case of performing double-sided copying of a plurality of copies, after copying the sheets on the front side, stacking the copy sheets and supplying the copy sheets to the image forming apparatus again, if the sheets are double fed, the copying operation is interrupted. However, there is a problem that the user has to restart the copying of the table or carry out the manual paper feeding only for the number of copies that are double-fed.

However, according to the present invention, the pressure-sensitive conductive rubber is used for the feeding rotary member, and the double feed is detected by converting the change in the length and thickness of the original document into an electric signal. Double feeding of documents can be reliably detected, and an image reading operation or an image forming operation can be detected immediately after double feeding, and recovery can be facilitated.

[0032]

A paper sheet feeding device of the present invention is a storage means for storing a plurality of paper sheets, a conveying means for conveying paper sheets, and the storage means. A take-out means for taking out the paper sheets one by one and supplying them to the conveying means,
A feeding rotating means provided on the conveying means for feeding the paper sheets taken out by the taking-out means, abutting against the feeding rotating means, and rotating in a direction opposite to the rotating direction of the feeding rotating means. 2 by the above-mentioned taking-out means
Separation means for separating the first and subsequent sheets from the first sheet, and a separation means on the conveying means, which is provided downstream of the separating means and abuts on the feed rotating means, and is applied by the applied pressure. It has a conductive rubber whose resistance value changes, and is composed of an output means for outputting a resistance value change of the pressure-sensitive conductive rubber according to the pressure accompanying the feeding of the paper sheets.

The paper sheet feeding apparatus of the present invention is a storage means for storing a plurality of paper sheets, a conveying means for conveying the paper sheets, and one paper sheet stored in the storage means. Take-out means for feeding to the carrying means, feeding rotation means provided on the carrying means for feeding the paper sheets taken out by the taking-out means, contacting the feeding rotation means, and feeding the feeding means. On the conveying means, a separating means for separating the second and subsequent sheets taken out by the taking-out means from the first sheet by rotating the rotating means in a direction opposite to the rotating direction. The pressure-sensitive material is provided downstream of the separating means, is in contact with the feeding / rotating means, and has a conductive rubber whose resistance value changes according to the applied pressure, and which has a pressure corresponding to the pressure accompanying the feeding of the paper sheets. Output means to output the resistance change of the conductive rubber of First detection means for detecting an electric signal corresponding to a change in resistance value of the pressure-sensitive conductive rubber from the means, and a conveyance state of the paper sheet is detected by the electric signal detected by the first detection means. It is composed of a second detecting means.

[0034]

According to the present invention, the rotary feeding means for feeding the paper sheets is brought into contact with the separating means rotating in the opposite direction to the means for feeding and separating the paper sheets one by one. On the downstream side of the separating means on the means, there is a conductive rubber which is in contact with the feeding rotation means and whose resistance value changes by the applied pressure. An output means for outputting a change in resistance value of the pressure-sensitive conductive rubber is provided, an electric signal corresponding to the output change in resistance value is detected, and the feeding state of the paper sheet is detected by the detected electric signal. It is something that is done.

[0035]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a copying machine as an example of the image forming apparatus according to the present invention.

That is, reference numeral 1 is a main body of the copying machine.
A document automatic feeding device (AD) as a paper sheet feeding device of the present invention which automatically conveys a document (paper sheet) O above the
F: Auto document feeder) 20 is installed.

A document table (transparent glass) 2 on which the document O fed by the automatic document feeder 20 is placed is provided on the upper surface of the copying machine body 1.

A document scanning unit 3 for scanning and reading a document O set on a document table 2 is provided in the main body 1 of the copying machine, and an image forming unit 4 is provided at the lower part. The original table 2 is fixed to the main body 1.

The document scanning section 3 is constructed, for example, as shown in FIG. That is, the first carriage 7 on which the exposure lamp 6 as a light source is installed, the second carriage 9 on which the mirror portion 8 that bends the optical path is installed, and the zoom lens 1.
0, the reflected light from the document O is guided to the photoelectric conversion unit 11, and the mirror unit 12 that corrects the optical path length at the time of zooming, the photoelectric conversion unit 11 that receives the reflected light from the document O, and the positions of these units are changed. Drive system (not shown) and photoelectric conversion unit 11
Output, that is, image data is converted from analog data to digital data by an A / D converter 13.

The first carriage 7 has an exposure lamp 6 for irradiating the original O with light, a reflector 14 as a reflecting mirror for collecting the light from the exposure lamp 6 on the surface of the original, and a reflected light from the original O. A mirror 15 that guides the second carriage 8 is mounted.

The mirror section 8 is composed of mirrors 8a and 8b for guiding the light guided by the mirror 15 to the zoom lens 10. The first and second carriages 7 and 9
Are connected to each other by a timing belt (not shown), and the second carriage 9 moves in the same direction at half the speed of the first carriage 7. Thereby, scanning can be performed so that the optical path length to the zoom lens 10 is constant.

The zoom lens 10 has a fixed focal length and can be moved in the optical axis direction during zooming.

The mirror section 12 includes two mirrors 12a,
12b, the positions of the mirrors 12a and 12b are changed according to the change of the optical path length corresponding to the selected magnification, and the light from the zoom lens 10 is changed to the two mirrors 12a, By bending the optical path at 12b, the light is guided to the photoelectric conversion unit 11.

The photoelectric conversion unit 11 photoelectrically converts the reflected light from the original O, and is mainly composed of, for example, a CCD type line image sensor. In this case, one pixel of the document O corresponds to one element of the CCD sensor. The output of the photoelectric conversion unit 11 is output to the A / D conversion unit 13.

The movement of the first and second carriages 7 and 9 and the mirrors 12a and 12b is performed by a stepping motor (not shown).

The first and second carriages 7 and 9 are provided with a timing belt (not shown) suspended between a drive pulley (not shown) connected to the rotary shaft of the stepping motor and an idle pulley (not shown). It is designed to be moved according to the movement of.

In the zoom lens 10, a spiral shaft (not shown) is rotated by a corresponding stepping motor (not shown), and the spiral lens is moved in the optical axis direction.

The image forming section 4 comprises, for example, an image forming section in which a laser optical system and an electrophotographic system capable of forming an image on a transfer sheet are combined.

Next, the structure of the automatic document feeder 20 will be described with reference to FIG. Automatic document feeder 2
0 is a unit, and the cover main body 2 as its housing
The rear end edge of the first copying machine 1 is attached to the rear end edge of the upper surface of the copying machine main body 1 via a hinge device (not shown) so as to be openable and closable.
If necessary, the entire automatic document feeder 20 can be rotationally displaced to open the original table 2.

As shown in FIG. 1, on the upper surface of the cover main body 21 slightly leftward, a document feeding table 22 is provided as a document holding means capable of holding a plurality of documents O collectively.

Further, the originals O held by the original feeding table 22 with the image forming surface facing upward are sequentially taken out one by one from the lower side and supplied to one end side (the left end side in the drawing) of the original table 2. A take-out / feeding means 23 is provided.

The take-out / feeding means 23 is constructed as follows.

That is, the document stopper 2a is arranged along the inclined lower end of the document feeding table 22 and the left edge of the document table 2.
Horizontal U-shaped paper feed path 25 so as to communicate with the upper surface of the sheet
Is provided so that the document O is inverted and guided so that the document forming surface faces down.

A shutter 25a for aligning the end surfaces of the originals O set on the original feeding table 22 is provided upstream of the paper feeding path 25, and a pickup roller 27 for taking out the original O is provided in the vicinity thereof. A weight plate 28 for pressing the original O against the pickup roller 27, an empty sensor 29 as an original detecting sensor for detecting the setting state of the original O on the original feeding table 22, and an actuator 30 of the empty sensor 29 are provided. Has been done.

Further, in the original pick-up direction of the pickup roller 27, the paper feed roller 31 and the paper feed roller 31
A separation brake unit 26 attached to the frame 32 of the main body and contacting very lightly and a detection member (described later) 33 are arranged so that the originals O are reliably fed one by one. The detection member 33 is provided on the downstream side of the separation brake unit 26, and is provided in contact with the paper feed roller 31 together with the separation brake unit 26. The separation brake unit 26 is composed of a friction member. The detection member 33 detects the thickness of the original document O, the conveyance state of the original document O such as double feeding (overlapping conveyance), and the pressure-sensitive conductive rubber 33a (which will be described later) for detecting the opening / closing of the automatic original feeding device 20. Built in.

Further, at the downstream portion of the sheet feeding path 25, an aligning roller 3 as a pair of registration rollers for correcting the inclination (skew) of the original O and adjusting the supply timing.
4 and 34 are provided, and a registration sensor 36 that is located in front of the aligning rollers 34 and 34 and detects the document O to adjust the operation timing of the aligning rollers 34 and 34 is provided. Further, a document size sensor is provided downstream of the aligning rollers 34, 34 to detect the document O and detect the size of the document O.

Further, a document transport belt 37 as a document transport means is stretched to cover the upper surface of the document table 2. Then, the document O fed by the take-out feeding means 23 is conveyed from one end side (left end side) of the document table 2 to the other end side (right end side), and is ejected at the right side portion of the cover body 21. The paper unit 38 discharges the paper to a paper discharge receiving portion 39 formed on the upper surface of the cover body 21.

The original conveying belt 37 is a wide endless belt whose outer surface is hung on a pair of belt rollers 40, 40, and has a structure capable of traveling in both forward and reverse directions by a belt drive mechanism (not shown) described later. Has become. Further, a plurality of belt pressing rollers 41 for pressing the belt surface onto the original table 2 and a set switch 42 used as a release switch at the time of jam are provided on the back surface side of the inner peripheral portion of the original conveying belt 37. Has been.

The paper discharging means 38 is constructed as follows.

That is, the right edge of the document table 2 and the paper discharge receiving portion 3
A lateral U-shaped sheet discharge path 43 is provided so as to communicate with the sheet 9, and the original O is inverted and discharged so that the original forming surface faces up.

A transport roller 44, a pinch roller 45 for pressing the document O on the transport roller 44, and a document detecting means for detecting the trailing end of the document O sent in the sheet discharge direction are provided in the middle portion of the paper discharge path 43. The paper discharge sensor 46 and the actuator 47 of the paper discharge sensor 46 are provided.

On the downstream side of the paper discharge path 43, a paper discharge roller 48 is arranged and a plate spring 49 for pressing the original O on the paper discharge roller 48 is provided.

Reference numeral 50 in the figure denotes a cover switch.

Next, the operation of the automatic document feeder 20 configured as described above will be described with reference to FIGS. 3 to 7.

First, as shown in FIG.
A plurality of originals O are collectively set (placed) so as to abut against the shutter 25a. When the document O is placed, the actuator 30 is rotated and the empty sensor 29 is turned on. On the other hand, necessary information is input from the operation panel 52 described later. Then, the copy key 52c is pressed. As a result, the shutter solenoid 68 and the weight plate solenoid 70 are turned on, and the weight plate 28 is moved to the original O.
Of the shutter 25a from the transport path 25.
Will evacuate. Further, the pickup roller 27 and the paper feed roller 31 rotate, respectively, and the lowermost first original O on the original paper feed table 22 is taken out and fed, and a registration roller pair composed of aligning rollers 34 and 34 is formed. It is fed to the lower surface side of the document conveying belt 37 which is running in the feeding direction (see FIGS. 4 and 5). Then, the document is fed onto the document table 2, and thereafter, in order to abut the document O against the document stopper 24, after the trailing edge of the document O is detected by the registration sensor 36, the document transport belt 37 travels for a certain number of pulses and then The original O is returned by traveling in the reverse direction on the original conveyance belt 37 for a certain number of pulses, and the setting of the original O is completed (see FIGS. 6 and 7).

When the setting of the original O is completed, the original scanning unit 3 in the copying machine body 1 scans the original, and the image forming unit 4 starts the copying operation on the sheet as the transfer sheet. Will be done.

After the copying operation is completed, the original O is sent out from the original table 2 as the original conveying belt 37 travels, and is ejected to the paper ejection receiver 39 via the paper ejection means 38.

On the other hand, when the original O is sent out from the original table 2, the next original O is sent to the original table 2. Then, this operation is repeated until there is no original O set on the original feed table 22.

Next, the control circuit will be described with reference to the block diagram shown in FIG.

That is, a main controller 51 for controlling the entire copying machine 1 is provided. The main control unit 51 includes an operation panel 52 for instructing various operations, the document scanning unit 3,
An interface 53 for exchanging data with the image forming unit 4 and the automatic document feeder 20 is connected.

The operation panel 52 has a display section 52a for displaying operation contents and the like, and a setting key 52 for making various settings.
.., a copy key 52c for instructing the start of copying, an input mode switching key 52d, a clear key 52e, and the like.

The automatic document feeder 20 is provided with a control section 61 for controlling the entire automatic document feeder 20.
The controller 61 includes a driver 63 that drives a feeding motor 62 that is a drive source of the pickup roller 27 and the paper feed roller 31, aligning rollers 34, 34, a document conveyance belt 37, a conveyance roller 44, and a discharge roller. Paper roller 4
8, a driver 65 for driving a conveying motor 64, which is a drive source of the drive source 8, the empty sensor 29, the document size sensor 3
5, a registration sensor 36, a set switch 42, a paper discharge sensor 46, a cover switch 50, a driver 67 that drives an electromagnetic clutch 66 that interrupts the transmission of the rotational force of the conveying motor 64 to the aligning rollers 34, 34, A driver 69 that drives a shutter solenoid 68 that rotates the shutter 25a, a driver 71 that drives the weight plate solenoid 70 that rotates the weight plate 28,
A memory 72 for storing various data, an A / D converter 74 for converting a voltage value from the detection circuit 73 into a digital value, and an interface 60 for exchanging data with the copying machine 1 are connected.

The A / D converter 74 has an inverting output function and responds to a change in the voltage value from the detection circuit 73 that detects the voltage value obtained by the change in the resistance value of the pressure-sensitive conductive rubber 33a of the detection member 33. The digital value is output to the control unit 61. While the voltage value from the detection circuit 73 decreases, it outputs a digital value increasing in the positive direction.

The control section 61 is adapted to determine a carrying state such as double feeding (two-sheet overlapping feeding) of the original O based on the digital value supplied from the A / D converter 74. For example, when a digital value corresponding to the voltage value “V0” from the detection circuit 73 is supplied from the A / D converter 74,
It is determined that the original O is not conveyed, and the digital value corresponding to the voltage value “V1” from the detection circuit 73 is A / A.
When the document O is supplied from the D converter 74, it is determined that the document O is normally conveyed, and when the digital value corresponding to the voltage value “V2” from the detection circuit 73 is supplied from the A / D converter 74. , Determine whether the document O is double-fed.

As shown in FIGS. 9 and 10, the detection member 33 has a pressure-sensitive conductive rubber 33a. The pressure-sensitive conductive rubber 33a is attached to the sheet feeding roller 2 while being pressed by the support plate 33b. The support plate 33b is fixed to the frame 32 of the automatic document feeder 20 with a plastic screw via an insulating member 33c. A harness 33d that transmits a signal from the pressure-sensitive conductive rubber 33a to the detection circuit 73 is connected to the support plate 33b. The separation brake unit 26 is also attached to the frame 32 as described above.

Support plate 33b and pressure-sensitive conductive rubber 33a
Although the connection with may be made by a conductive adhesive, the mass productivity and the mechanical strength can be improved by inserting the support plate 33b when the pressure-sensitive conductive rubber 33a is molded. By using a spring material such as SUS or phosphor bronze, the support plate 33b can have both an electrode function and a pressure support function.

The other electrode 33e for extracting the signal is
As shown in FIG. 10, a part of the surface in contact with the paper feed roller 31 is formed by thick film printing with conductive ink. The electrode 33e made of this conductive ink has the flexibility to follow sufficiently even if the pressure-sensitive conductive rubber 33a is deformed under pressure.

Therefore, even when the thickness of the document O changes from the middle such as when the document O is double-fed, it can be deformed integrally with the pressure-sensitive conductive rubber 33a, thereby enabling reliable signal detection. Further, thick film printing does not have a risk of damaging the surface of the paper feed roller 31 unlike metal members. The conductive ink layer is usually 10 to 15 μm.

Further, as shown in FIG. 11, this portion may be formed by a flexible substrate 33f having a pattern 33g. In this case, the thickness is 20 to 30 μm. In this case, the connection with the harness 33e for signal extraction can be easily soldered by providing a land on the flexible board 33f.

The signal from the pressure-sensitive conductive rubber 33a is sent to the detection circuit 73 via the electrode 33f and the harness 33e.
Output to the input terminal 73a of the
It is output to the input terminal 73b of the detection circuit 73 via b and the harness 33d. For example, when the original O is not sandwiched between the pressure-sensitive conductive rubber 33a of the detection member 33 and the paper feed roller 31, the pressure on the pressure-sensitive conductive rubber 33a is P0 and the output voltage from the detection circuit 73 is V0. When one original O is sandwiched between the pressure-sensitive conductive rubber 33a and the paper feed roller 31, the pressure on the pressure-sensitive conductive rubber 33a is P1 and the output voltage from the detection circuit 73 is V1. When two originals O (for two originals O) are sandwiched between the pressure-sensitive conductive rubber 33a and the paper feed roller 31 (double feeding of the original O), the pressure-sensitive conductive rubber 33a.
Is P2 and the output voltage from the detection circuit 73 is V2.
(P2>P1> P0, V0>V1> V
2).

The relationship between the pressure of the pressure-sensitive conductive rubber 33a of the detection member 33 and the output voltage of the detection circuit 73 is as shown in FIG.

The pressure-sensitive conductive rubber 33a is composed of a conductive elastomer (elastic polymer such as silicone rubber) in which a conductive filler is dispersed in a polymer material to make the material conductive. Has been done. The pressure-sensitive conductive rubber 33a is an elastomer capable of taking out a resistance change as a response to a pressure stimulus among the conductive elastomers.
Also called ctive Rubber; PCR.

13 and 14 show the relationship between the typical pressure and resistance value of the pressure-sensitive conductive rubber 33a.

FIG. 13 shows the pressure dependence of the pressure-sensitive conductive rubber 33a in which carbon black is dispersed in the elastomer.

FIG. 14 shows the pressure dependency of the pressure-sensitive conductive rubber 33a in which conductive metal particles (particle diameter of copper, nickel, etc., 10 μm or more) are dispersed in silicon rubber.

In the case of FIG. 13, there is a resistance value change of about 2 to 3 digits, and in the case of FIG. 14, there is a resistance value change of 6 digits or more from 10 ⁸ Ωcm or more to 10 ² cm or less in volume resistivity. .

As shown in FIG. 15, the detection circuit 73 includes resistors R1 to R10, variable resistors VR1, VR2, and VR.
3, current detection type transistors Tr1 and Tr2, and an operational amplifier OP. Detection circuit 73
Is connected to the input ends 73a and 73b by the pressure-sensitive conductive rubber 33a.
The change in the resistance value from is supplied. The supplied current with respect to the change in the resistance value is adjusted by the variable resistors VR1 and R1 and becomes the base current of the transistor Tr1. Since the amplitude of the supplied resistance value change is unknown, the variable resistance (volume resistance) VR1 is provided instead of the fixed resistance. The base current of the transistor Tr1 is detected by the current detection rate of the transistor Tr1, and the emitter current of the transistor Tr1 is divided by the resistors R4 and R5. The current passing through the resistor R4 is detected by the transistor Tr2 at the current detection rate of the transistor Tr2, and the emitter current of the transistor Tr2 is divided by the resistors R6 and R7. The current passing through the resistor R7 is detected by the operational amplifier OP based on the reference voltage by VR3 / R7 times which is determined by the variable resistor VR3 and the resistor R7. The reference voltage input to the non-inverting input terminal of the operational amplifier OP is for input offset adjustment, and is adjusted by the variable resistor VR2. The signal (voltage value) detected by the operational amplifier OP is A / D via the resistor R10.
It is output to the converter 74.

In the above example, the two transistors Tr1,
The current detection rate was increased by using 2, but not limited to this,
You may make it use only one transistor Tr1. In this case, the detection circuit 73 has a transistor Tr.
A signal is output from 1 through the resistor R4.

Depending on the signal supplied to the input terminal 73b, it is necessary to insert another resistor between the input terminal 73b and the resistor R1.

Next, in the configuration as described above, FIG.
The operation will be described with reference to FIG. First, as shown in FIG. 3, a plurality of originals O are collectively set (placed) on the original feeding table 22 so as to abut against the shutter 25a. When the document O is placed, the actuator 30 is rotated and the empty sensor 29 is turned on. On the other hand, necessary information is input from the operation panel 52. Then, the copy key 52c is pressed. As a result, the control unit 61 turns on the shutter solenoid 68 and the weight plate solenoid 70.
As a result, the weight plate 28 suppresses the lifting of the document O, and the shutter 25a is retracted from the transport path 25.

The control section 61 is rotated by transmitting the rotational force of the sheet feeding motor 62 to the pickup roller 27. As a result, the document O on the document feed table 22 is taken out and sent between the separation brake unit 26 and the feed roller 31 and between the detection member 33 and the feed roller 31. At this time, the paper feed roller 31 is stopped. Then, the control unit 61
When the operation start command is received from the main control unit 51, is rotated by transmitting the rotational force of the paper feed motor 62 to the paper feed roller 31. As a result, the first lowermost original O on the original feeding table 22 is separated from the separation brake unit 33 and the feeding roller 3.
1 and the aligning roller 3
It is fed to the lower surface side of the document conveying belt 37 which is running in the feeding direction through a pair of registration rollers 4 and 34 (see FIGS. 4 to 6).

Then, when a certain time has passed since the pickup roller 27 and the paper feed roller 31 were rotated, the control section 61 changes the digital value from the A / D converter 74 to the voltage value "from the detection circuit 73". If it is a value corresponding to “V0”, it is determined that the document O is not conveyed, and a jam is determined. Further, when the digital value from the A / D converter 74 is a value corresponding to the voltage value “V2” from the detection circuit 73, it is judged that the document O is double-fed.

When the jam is determined, the controller 61 stops the paper feed motor 62 and the transport motor 64, and outputs the occurrence of the jam to the main controller 51 of the copying machine main body 1 through the interfaces 60 and 53. To do. The main control unit 51 guides the occurrence of the jam with the operation panel 52.

When the above-mentioned double feeding is judged, the control unit 6
1, the feeding motor 62 and the conveying motor 64 are stopped,
The occurrence of jam is output to the main controller 51 of the copying machine main body 1 through the interfaces 60 and 53. The main control unit 51 guides the occurrence of the double feed by the operation panel 52.

That is, by rotating the pickup roller 27, the original O is sent between the separation brake unit 26 and the paper feed roller 31, as shown in FIG. At this time, the paper feed roller 31 is stopped.

Then, by starting the rotation of the paper feed roller 31, the paper feed roller 31 and the original O, the originals O,
Due to the relationship of the friction coefficient between the separation brake unit 26 and the document O, only one document O is fed by the paper feed roller 31 with the passage of time.
Will be fed by. This is shown in FIG.
(C), It shows in (a) of FIG. Therefore, after the paper feed roller 31 has rotated for a certain period of time,
The pressure-sensitive conductive rubber 33a of the detection member 33 may be used to detect the thickness of the document O to detect the double feed. If, after this period has elapsed, when the document is double-fed as shown in FIG. 17B, the change in pressure due to the difference in the thickness of the document O can be detected.

When the original O is normally fed onto the original table 2, the original conveying belt 37 is moved after the rear end of the original O is detected by the original size sensor 35 in order to bring the original O into contact with the original stopper 24. After traveling for a certain number of pulses, the original conveying belt 37 is moved in the opposite direction for a certain number of pulses to return the original O, and the setting of the original O is completed.

When the setting of the document O is completed, the document scanning unit 3 in the copying machine main body 1 scans the document, and the image forming unit 4 starts the copying operation on the sheet as the transfer sheet. Will be done.

After the document scanning by the document scanning unit 3 is completed, the document O is sent out from the document table 2 as the document transport belt 37 travels, and is delivered via the paper delivery means 38 to the paper delivery receiving unit 3.
It is discharged to 9.

That is, when the actuator 43 is rotated by the leading edge of the original O and the paper discharge sensor 38 is turned on, the controller 61 stops the traveling of the original conveying belt 37. Further, after the discharge sensor 38 is turned off by the trailing edge of the document O (passing) and a predetermined time (several tens of msec) has elapsed, the control unit 61.
Stops the transport roller 44 and the paper discharge roller 48.

On the other hand, when the original O is sent out from the original table 2, the next original O is sent to the original table 2. Then, this operation is repeated until there is no original O set on the original feed table 22.

Next, another structural example of the detection member 33 will be described.

FIG. 18A shows an example in which the electrode layer 33i is formed in the middle of the pressure-sensitive conductive rubber 33a of the detection member 33 shown in FIG. In this case, it is not necessary to dispose an electrode for signal detection in a portion that contacts the separation roller 31.

Therefore, for example, when the conductive layer 33i is formed by thick film printing, the conductive layer 33i is abraded by abrasion.
It is possible to prevent the possibility that i will be damaged. Also,
As shown in FIG. 18B, the conductive layer 33i further includes
A similar effect can be obtained by forming a protection member (eg Mylar) 33k having a small friction coefficient on the separation roller 31 side. In this case, a high signal can be obtained efficiently.

The detection member 33 can be formed by inserting a support plate and a metal plate as an electrode layer and integrally molding them. One of the separated brakes formed in this way
An example is shown in FIG.

The intermediate electrode as the conductive layer 33i may be a conductive ink formed by thick film printing or a flexible substrate as described above.

20 and 21 show an embodiment having a structure in which pressure is applied to the pressure-sensitive conductive rubber 33a through the link 303. In this case, the pressure-sensitive conductive rubber 33a is housed in the housing 33h, and the housing 33h is insulated by the insulating member 33n.
It is attached to the frame 32 of the main body via.

The pressure-sensitive conductive rubber 33a has different detection sensitivity depending on the pressure value. For example, in FIG.
Between 1 and P2, the resistance value with respect to pressure is almost linear. However, it is not maintained between P0 and P1.

Furthermore, it can be seen that the resistance value changes little with pressure.

That is, by the pressure-sensitive conductive rubber 33a,
In order to detect the feeding state, it is necessary to set the applied pressure in order to use the optimum sensitivity region.

Therefore, assuming that the pressure-sensitive conductive rubber 33a is pressed through the link 303, P = m in FIGS. 20 and 21.
Since there is a relational expression of × P ′ / l, it is easy to set P ′ in the optimum detection region of the pressure-sensitive conductive rubber 33a by optimizing the ratio of m / l. FIG. 22 shows the separation roller 31.
Is applied to pressure sensitive conductive rubber 33a and auxiliary spring 33l.
3 shows an example performed by. The pressure-sensitive conductive rubber 33a and the auxiliary spring 331 are arranged in the same phase with respect to the direction in which the pressure is applied.

The pressure P applied to the separating rubber is converted into P'through the link 303 as described above.

The pressure applied to the auxiliary spring 33l is P
_'1, if such a pressure to the pressure sensitive conductive rubber 33a and _{P'2, P'= P'1 +} P' from the _second relational expression is satisfied, by selecting the pressure _P'1 auxiliary spring 33l it becomes easier to set such pressure to the pressure sensitive conductive rubber 33a of _P'2 optimum detection area for double feed detection.

FIG. 23 shows an embodiment in which an adjusting screw 33m as a mechanism for adjusting the pressure applied to the pressure-sensitive conductive rubber 33a and the auxiliary spring 33l is further added. By adding the adjusting screw 33m in this way, it is possible to restore the original pressing force even when the pressing force required for the separating function is reduced due to the settling after the pressurizing operation is repeated. Further, it goes without saying that the degree of freedom in setting the pressure so that both the separating function and the double feeding function can be set can be expanded.

As described above, the pressure-sensitive conductive rubber 33a
By reading the change in the resistance value corresponding to the pressing force of, the jam can be detected as well as the double feeding of the original O.

Although the example applied to the document feeding device has been described so far, the invention can also be applied to a sheet feeding device of a printer or a copying machine (for example, an automatic double-sided sheet feeding device).

Next, a length detection circuit for detecting the length of the original O is provided based on the output signal of the detection circuit 73, and the conveyance state of the original O is judged based on the detection result of this length detection circuit. An example will be described. In this case, as shown in FIG. 24, the control circuit has a configuration in which a length detection circuit 75 is provided instead of the A / D converter 74 of FIG.

The length detection circuit 75 detects the length of the original O fed according to the change in the voltage value from the detection circuit 73 obtained by the change in the resistance value of the pressure-sensitive conductive member 33a of the detection member 33. The first original O to be fed
Based on the length of the document, a detection signal indicating whether or not the length of the second and subsequent originals O to be fed is longer than the reference, or 1
A detection signal indicating whether or not the length of the first original O is longer than the length of the second original O is output to the control unit 61.

The control section 61 determines whether or not the original O is conveyed abnormally based on the detection signal from the length detection circuit 75.
For example, when the control unit 61 receives a detection signal from the length detection circuit 75 that the length of the second original document O is longer than the reference, the control unit 61 determines the double feeding of the second original document O or later. ,
When the length detection circuit 75 supplies a detection signal that the length of the first original O is longer than the length of the second original O,
It is determined whether the first original O is double-fed.

As shown in FIG. 25, the length detecting circuit 75 includes a binarizing circuit 101, a delay pulse generating circuit 102, inverters 103 and 108, a counter 104, and an FF circuit 1.
05, the latch circuits 106 and 107, and the comparator 109.
It is composed by.

The binarization circuit 101 binarizes the voltage value from the detection circuit 73 to output a detection signal when the original O passes through the detection member 33, as shown in FIG. When the document O exists between the detection member 33 and the paper feed roller 31, it outputs a signal of "L" level, and otherwise outputs a signal of "H" level. The binarized output from the binarization circuit 101 is supplied to the delay pulse generation circuit 102 and the inverter 1
03 through counter 104, latch circuits 106, 10
7 is supplied.

The delay pulse generating circuit 102 switches when the passage detection signal as the binarized output from the binarizing circuit 101 switches (when switching from the “L” level to the “H” level). A delayed pulse as shown in FIG. 26B is generated, and this delayed pulse is output to the FF circuit 105.

The counter 104 counts the number of master clocks supplied from an oscillator (not shown) while the passage detection signal (“L” level) as the binarized output from the binarization circuit 101 is supplied. The counting result is output to the latch circuits 106 and 107.

That is, the counter 104 has the detecting member 3
If the original O does not exist between the sheet feeding roller 3 and the paper feed roller 31,
The number of clocks is kept at "0", and the number of clocks is counted from "0" while the document O is present between the detection member 33 and the paper feed roller 31.

The FF circuit 105 is a D-type flip-flop, the data input terminal D and the clock input terminal CLK are held at "H" level, and the delay pulse from the delay pulse generating circuit 102 is applied to the clear input terminal CLR. A preset signal (“L” level) from the control unit 61 is supplied to the preset input terminal PRE. The preset input terminal PRE is normally held at "H" level as shown in FIG.

As a result, the FF circuit 105 keeps the chip select signal (Q output) at "H" until the first delay pulse is supplied from the delay pulse generating circuit 102, as shown in (c) of FIG. After the first delay pulse is supplied, the chip select signal is "L".
It is a level. That is, when the first original O has passed, it is switched from the "H" level to the "L" level, and thereafter, is held at the "L" level.

Further, when the "L" level preset signal is supplied from the control section 61, the set output becomes "H" level again.

The chip select signal (C
(S signal) is supplied to the latch circuit 107 and
The signal inverted by the inverter 103 is supplied to the latch circuit 106 as a chip select signal (CS signal).

In the latch circuit 106, the signal output from the inverter 103 becomes "H" level when the original O exists, and the counter 104 counts up only in this state. The inverter 103 is used for the latch clock.
Is used to store the count result of the counter 104 corresponding to the length of the first original O. At the time of the first original, the Q output of the FF circuit 105 becomes "H" level, and the signal is inverted by the inverter 108 and becomes "L".
It becomes a level and is supplied to the latch circuit 106, and the output of the latch circuit 106 becomes valid. At that time, the latch circuit 107
Is supplied with "H" level, and the output becomes invalid. The count value of the latch circuit 106 is output to the comparator 109.

The latch circuit 107 stores the count result of the counter 104 corresponding to the length of the second and subsequent originals O using the fall of the inverter 103 as the latch clock. In the case of the second and subsequent originals, the chip select signal is inverted as in the case of the first original, the latch circuit 106 becomes "H" level, and the output of the latch circuit 106 becomes invalid. At that time, since the “L” level is supplied to the latch circuit 107, the output of the latch circuit 107 becomes valid.
The count value of the latch circuit 107 is output to the comparator 109.

The comparator 109 includes a count value corresponding to the length of the first original O from the latch circuit 106 and the latch circuit 1
By comparing the count value corresponding to the length of the second and subsequent originals O from 07, it is confirmed that the length of the second and subsequent originals O is the same as the length of the first original O. Signal, signal indicating that the length of the second original document O is longer than the length of the first original O, signal length of the first original O is longer than that of the second original O A signal to the effect is output to the control unit 61.

For example, the comparator 109 outputs 3-bit comparison results CPR1, CPR2 and CPR3. When the length of the first original O is longer than the length of the second and subsequent originals O, the comparison result CPR1 is set to the “L” level, and the length of the second and subsequent originals O is the first original. When the length of the original O is longer than the length of O, the comparison result CPR2 is set to the “L” level, and when the length of the second original O and the original O is the same as the length of the first original O,
The comparison result CPR3 is set to "L" level.

The period of the master clock is a predetermined value, and the original O by the paper feed roller 31 is
Since the transfer speed of the latch circuit is also constant, the latch circuit 1
The length of the document O can be detected from the count values stored in 06 and 107.

The comparator 109 and the control section 61 may be connected by three signal lines or may be connected by three-state signal lines. However, when a 3-state signal line is used, the control unit 61 has a CPU, a data bus, an address bus, and a buffer driver interface, and the comparator 109 and the CPU are connected via the data bus and the address bus. Connected, empty sensor 2
, ..., drivers 63, ... Are connected to the buffer driver interface, and the buffer driver interface and the CPU are connected via a data bus and an address bus.

In this case, the number of CPU ports can be reduced, and the CPU can read the signal from the comparator 109 when necessary. Next, in such a configuration, the operation will be described with reference to the flowcharts shown in FIGS. 27 and 28. For example, now, a plurality of originals O are collectively set (placed) on the original feeding table 22 so as to abut against the shutter 25a.
To do. When the document O is placed, the actuator 30 is rotated and the empty sensor 29 is turned on. On the other hand, necessary information is input from the operation panel 52. Then, the copy key 52c is pressed. As a result, the control unit 61 turns on the shutter solenoid 68 and the weight plate solenoid 70. As a result, the weight plate 28 suppresses the lifting of the document O, and the shutter 25a is retracted from the transport path 25.

Further, the control section 61 instructs the pickup roller 27 and the sheet feed roller 31 to transmit the rotational force of the sheet feed motor 62, thereby rotating them. As a result, the first lowermost original O on the original feeding table 22 is taken out, separated and fed by the separating member and the feeding roller 31, and fed between the detecting member 33 and the feeding roller 31. At the same time, it is fed to the lower surface side of the document conveying belt 37 which is running in the feeding direction via a pair of registration rollers composed of aligning rollers 34.

When the first original O passes between the detection member 33 and the paper feed roller 31, the length detection circuit 7 uses the data corresponding to the length of the first original O as a reference value.
5 is stored in the latch circuit 106.

That is, when the leading edge of the first original O reaches between the detection member 33 and the paper feed roller 31, the voltage value detected by the detection circuit 73 causes the binarization circuit 101 to change to the “L” level. The signal of is output. With this signal, the counter 104 starts counting with a clock from an oscillator (not shown). At this time, the chip select signal of the FF circuit 105 is at "H" level, and the latch circuit 10
The count result of the counter 104 is latched at 6.

When the trailing edge of the first original O passes between the detection member 33 and the paper feed roller 31, the detection circuit 7 is operated.
The binarization circuit 101 outputs an "H" level signal according to the voltage value detected in 3. The counter 104 is cleared by this signal. As a result, the latch circuit 10
6, the number of clocks corresponding to the first original O is stored as a reference value. Further, when the binarization circuit 101 outputs a signal of "H" level, the delay pulse generation circuit 102 generates a delay pulse. As a result, the FF circuit 10
5 is cleared, and the chip select signal becomes "L" level.

When the first original O is normally fed onto the original table 2, the first original O is placed on the original stopper 2.
In order to abut against the sheet No. 4, the document size detector 35 detects the trailing edge of the document O, the document transport belt 37 travels for a fixed number of pulses, and then the document transport belt 37 travels for a fixed number of pulses in the reverse direction. The original O is returned and the setting of the original O is completed.

When the setting of the first original O is completed, the original scanning unit 3 in the main body 1 of the copying machine scans the original, and accordingly, the image forming unit 4 sets a sheet as a transfer sheet. The copying operation will be started.

After the document scanning by the document scanning unit 3 is completed, the first document O is sent out from the document table 2 as the document transport belt 37 travels, and is delivered via the paper delivery means 38 to the paper delivery receiving unit. It is discharged to 39.

On the other hand, when the first original O is sent out from the original table 2, the second original O is sent from the original feeding table 22 onto the original table 2 as described above.

When the second original O passes between the detection member 33 and the paper feed roller 31, the data corresponding to the length of the second original O and the length of the first original O are obtained. Is compared with the reference value corresponding to, and the comparison result is output to the control unit 61.

That is, when the leading edge of the second original O reaches between the detection member 33 and the paper feed roller 31, the voltage value detected by the detection circuit 73 causes the binarization circuit 101 to go to "L" level. The signal of is output. With this signal, the counter 104 starts counting with a clock from an oscillator (not shown). At this time, the chip select signal of the FF circuit 105 is at "L" level, and the latch circuit 10
The count result of the counter 104 is latched at 7.

When the trailing edge of the second original O passes between the detection member 33 and the paper feed roller 31, the detection circuit 7 is operated.
The binarization circuit 101 outputs an "H" level signal according to the voltage value detected in 3. The signal polarity of this signal is inverted by the inverter 108 and becomes "L" level, which is input to the clear terminal of the counter 104. Since this terminal is valid at the "L" level, the counter 104 is cleared by the input of the "L" level signal.

The output of the inverter 108 is the latch circuit 10.
The latch circuit 107 also latches the output value of the counter 104 immediately before clearing. As a result, the latch circuit 107 stores the number of clocks corresponding to the second document O. As a result, the comparator 109
By comparing the count value corresponding to the length of the first original O from the latch circuit 106 with the count value corresponding to the length of the second and subsequent originals O from the latch circuit 107,
When the length of the first original O is longer than the length of the second and subsequent originals O, the comparison result CPR1 is set to "L" level, and 2
When the length of the original O after the first is longer than the length of the original O of the first, the comparison result CPR2 is set to the “L” level, and the length of the original O after the second is O of the first original. If it is the same as the length of, the comparison result CPR3 is set to the "L" level.

As a result, the control section 61 determines that the length detection circuit 7
When a detection signal indicating that the length of the second original document O is longer than that of the first original document O is supplied from the fifth to fifth sheets, it is determined that the second original document O is double-fed, and the length detection circuits 75 to 1 When a detection signal that the length of the first original O is longer than the length of the second original O is supplied, it is determined that the first original O is double-fed.

When the double feed is judged, the control section 61 stops the feeding operation and outputs to the main control section 51 the fact that the double feed has occurred. As a result, the main control unit 51 guides the occurrence of double feed on the display unit 52a of the operation panel 52.

When a detection signal indicating that the length of the second original O and the length of the first original O are the same is supplied from the length detection circuit 75 to the original O, the control section 61 causes the control section 61 to The second original O is scanned and discharged, and the third original O is fed from the original feed table 22 onto the original table 2 in the same manner as described above.

For the third and subsequent originals, the determination of double feeding is made and processed in the same manner as described above.

As described above, when the length detection circuit 75 determines the double feeding, even if the originals O to which photographs and the like are attached are mixed, the length of the original O to be cut and the reference Since the length of the original O does not change, the cut and pasted original O is not erroneously detected as a double feed.

Further, in the above example, when double feeding is judged,
Although the case where the feeding operation is stopped and the occurrence of double feeding is guided on the display portion 52a has been described, the display portion 52a may be used to guide the number of documents before the double feeding occurs.

In this case, as shown in FIG. 29, the delay pulse from the delay pulse generating circuit 102 in the length detecting circuit 75 is supplied to the control section 61, and the memory 72 is provided with the number counting section 72a. This can be realized by the control unit 61 counting up the count value of the number counting unit 72a of the memory 72 every time the delay pulse from the delay pulse generating circuit 102 is supplied.

At the time of restart, the sheet number counter section 72a is cleared to "0" when the first sheet is double-fed, and when the second and subsequent sheets are double-fed, the sheet count value immediately before double-feeding is set. Hold. Accordingly, at the time of restart, the user may set the document on the document feed table 22 from the document O that has been double-fed.

According to this structure, at the time of double feeding,
It is not necessary to perform the sheet feeding operation again from the first sheet, and the user can save time.

When a preset signal (“L” level) is supplied from the control unit 61 to the FF circuit 105 when a multi-feed or the like occurs during the feeding operation of a plurality of originals O. , The reference data of the latch circuit 106 is initialized. As a result, the length data for the first original O after the double feeding is canceled is stored in the latch circuit 106 as a reference value. In this case, timing charts of the chip select signal with respect to the preset signal, the output of the binarization circuit 101, and the delay pulse are as shown in (a) to (d) of FIG.

If the preset signal from the control unit 61 is not supplied to the FF circuit 105 when a multi-feed or the like occurs during the feeding operation of a plurality of originals O, the reference data of the latch circuit 106 is supplied. Is stored and held in the latch circuit 106 as the reference value for the length data for the first original O before the multi-feed. Flow charts in this case are shown in FIGS. 31 and 32.

As a result, the first original O
The double feed for can be detected immediately.

Next, a thickness detection circuit for detecting the thickness of the original O based on the output signal (voltage value) from the A / D converter 74 of FIG. 8 is provided. Based on the detection result of this thickness detection circuit, An example of determining the conveyance state of the document O will be described. In this case, the control circuit, as shown in FIG.
A thickness detection circuit 76 is provided between the converter 74 and the control unit 61.

The thickness detection circuit 76 corresponds to the change in the voltage value from the detection circuit 73 obtained by the change in the resistance value of the pressure-sensitive conductive member 33a of the detection member 33, and corresponds to the A / D converter 7.
The thickness of the original O to be fed is detected according to the digital value from 4, and the thickness of the first original O to be fed is used as a reference for the second and subsequent sheets to be fed. Output a detection signal indicating whether the thickness of the original O is thicker than the reference, or a detection signal indicating whether the thickness of the first original O is thicker than the thickness of the second original O. It is output to the control unit 61.

The control section 61 determines whether or not the original O is conveyed abnormally based on a detection signal from the thickness detection circuit 76. For example, when the detection signal is supplied from the thickness detection circuit 76 that the thickness of the second and subsequent originals O is thicker than the reference, the control unit 61 determines the double feeding of the second and subsequent originals O. , When the thickness detection circuit 76 supplies a detection signal that the thickness of the first original O is thicker than the thickness of the second original O, 1
It is determined whether the document O of the first sheet is double-fed.

As shown in FIG. 34, the thickness detecting circuit 76 includes a binarizing circuit 111, a delay pulse generating circuit 112, and an F circuit.
F circuit 113, delay circuits 114 and 115, inverter 1
16, 120, address generation counter 117, RA
It is composed of an M118 and a comparator 119.

The binarizing circuit 111 binarizes the voltage value from the detecting circuit 73 to output a detection signal when the original O passes through the detecting member 33, as shown in FIG. When the document O exists between the detection member 33 and the paper feed roller 31, it outputs a signal of "L" level, and otherwise outputs a signal of "H" level. The binarized output from the binarizing circuit 111 is supplied to the delay pulse generating circuit 112.

The delay pulse generation circuit 112 switches when the passage detection signal as the binarized output from the binarization circuit 111 is switched (when switched from the “L” level to the “H” level). A delay pulse as shown in FIG. 26B is generated, and this delay pulse is output to the FF circuit 113.

The FF circuit 113 is a D-type flip-flop, the data input terminal D and the clock input terminal CLK are held at "H" level, and the delay pulse from the delay pulse generating circuit 112 is applied to the clear input terminal CLR. A preset signal (“L” level) from the control unit 61 is supplied to the preset input terminal PRE. The preset input terminal PRE is normally held at "H" level as shown in FIG.

As a result, the FF circuit 113 keeps the chip select signal (Q output) at "H" until the first delay pulse is supplied from the delay pulse generation circuit 112, as shown in (c) of FIG. After the first delay pulse is supplied, the chip select signal is "L".
It is a level. That is, the chip select signal is switched from the "H" level to the "L" level when the first original O passes, and is held at the "L" level thereafter.

Further, when the "L" level preset signal is supplied from the control section 61, the chip select signal becomes "H" level again.

The chip select signal from the FF circuit 113 is supplied to the delay circuit 115, inverted by the inverter 116, and supplied to the delay circuit 114.

The delay circuits 114 and 115 have a latch function for temporarily storing the digital value from the A / D converter 74, and delay the stored digital value for a predetermined time and output it. The output of the delay circuit 114 is the RAM 11
8 and the output of the delay circuit 115 is supplied to the comparator 119.
Is supplied to. By using the delay circuit 115, 2
Even if the conveyance timings of the originals O on and after the first sheet are deviated, the thickness can be detected and allowed.

The address generation counter 117 outputs the output of the binarization circuit 111 when the start signal output from the control section 61 at the same time as the instruction to start the rotation of the original O to the paper feed roller 31 is supplied. Inverter 120
The master clock from the oscillator (not shown) is counted when the signal inverted by the signal becomes "H" level, and the address is determined by the RAM 11 when the count value reaches a predetermined count value.
It is designed to output to 8. The address generated from the address generation counter 117 is the first document O.
Is the write address and the read address is the read address for the second and subsequent originals O.

The clear terminal of the counter 117 has the above-mentioned 2
If the output of the binarization circuit 111 is supplied through the inverter 120 and there is no document O, the output of the inverter 120 is at "0" level and the count value is clear "0".

The RAM 118 stores the digital value from the delay circuit 114 at the address when the write signal is supplied from the control section 61 and the address is supplied from the address generation counter 117. This gives 1
Data indicating the thickness of the first document O at a predetermined position is stored. Further, the RAM 118 is provided with a counter 117 for address generation when a read signal is supplied from the control section 61.
The content of the address from is read into comparator 119.

The comparator 119 has a built-in subtractor, and data within a predetermined range based on the thickness data for the first original O supplied from the RAM 118 and the delay circuit 1.
By comparing the thickness data with respect to the second and subsequent originals O supplied from 15, a signal indicating that the thickness of the second and subsequent originals O is the same as the thickness of the first original O, 2 A signal indicating that the thickness of the original document O after the first sheet is thicker than that of the first original document O, and a signal indicating that the thickness of the first original document O is thicker than the thickness of the second original document O. Is output to the control unit 61.

For example, the comparator 119 outputs 3-bit comparison results CPR4, CPR5 and CPR6. When the length of the first original O is thicker than the thickness of the second and subsequent originals O, the comparison result CPR4 is set to the “L” level, and the thickness of the second and subsequent originals O is the first original. If it is thicker than the thickness of O, the comparison result CPR5 is set to the “L” level, and if the thicknesses of the second and subsequent originals O are the same as the thickness of the first original O,
The comparison result CPR6 is set to "L" level.

The comparator 119 and the control section 61 may be connected by three signal lines or three-state signal lines.

Next, in such a configuration, as shown in FIG.
The operation will be described with reference to the flowchart shown in FIG. For example, now, a plurality of originals O are collectively set (placed) on the original feeding table 22 so as to abut against the shutter 25a. When the document O is placed, the actuator 30 is rotated and the empty sensor 29 is turned on. On the other hand, necessary information is input from the operation panel 52. Then, the copy key 52c is pressed. Thereby, the control unit 61
Is a shutter solenoid 68 and a weight plate solenoid 70
And turn on. As a result, the weight plate 28 suppresses the lifting of the document O, and the shutter 25a is retracted from the transport path 25.

The control section 61 also instructs the pickup roller 27 and the sheet feed roller 31 to transmit the rotational force of the sheet feed motor 62, thereby rotating the pickup roller 27 and the sheet feed roller 31. As a result, the lowermost first original O on the original feeding table 22 is taken out, separated and fed by the separating member 26 and the feeding roller 21, and the aligning roller 3
It is fed to the lower surface side of the document conveyance belt 37 which is running in the feeding direction via a pair of registration rollers 4 and 34.

When the first original document O passes between the detection member 33 and the paper feed roller 31, the first original document O is detected.
The data corresponding to the thickness is stored in the RAM 118 in the thickness detection circuit 76 as a reference value.

That is, when the leading edge of the first original O reaches between the detection member 33 and the paper feed roller 31, the voltage value detected by the detection circuit 73 causes the binarization circuit 111 to go to "L" level. The signal of is output. With this signal, the counter 117 starts counting clocks from an oscillator (not shown). At this time, the chip select signal of the FF circuit 113 is at “H” level, the signal inverted by the inverter 116 is connected to the select terminal of the delay circuit 114, and the delay circuit 114 receives the signal from the A / D converter 74. The digital value corresponding to the voltage value of the detection circuit 73 is latched. When it is a child, the chip select terminal of the delay circuit 115 is at "H" level, so it is inactive. In addition, the control unit 6
A write signal is supplied from 1 to the RAM 118.

When the address from the counter 117 is supplied to the RAM 118, the RAM 118 stores the digital value from the delay circuit 114 at that address. As a result, the thickness data of the first original O is stored in the RAM 118 as a reference value. When the trailing edge of the first original O passes between the detection member 33 and the paper feed roller 31,
The binarization circuit 111 outputs an “H” level signal according to the voltage value detected by the detection circuit 73. The counter 117 is cleared by this signal. When the binarizing circuit 111 outputs a signal of “H” level, the delay pulse generating circuit 112 generates a delay pulse. As a result, the FF circuit 113 is cleared and the chip select signal becomes the "L" level.

When the first original O is normally fed onto the original table 2, the first original O is placed on the original stopper 2.
In order to abut against the sheet No. 4, the document size detector 35 detects the trailing edge of the document O, the document transport belt 37 travels for a fixed number of pulses, and then the document transport belt 37 travels for a fixed number of pulses in the reverse direction. The original O is returned and the setting of the original O is completed.

When the setting of the first original O is completed, the original scanning unit 3 in the main body 1 of the copying machine scans the original, and accordingly, the image forming unit 4 sets the sheet as a transfer sheet. The copying operation will be started.

After the document scanning by the document scanning unit 3 is completed, the first document O is sent out from the document table 2 as the document transport belt 37 travels, and is discharged via the paper discharging unit 38. It is discharged to 39.

On the other hand, when the first original O is sent out from the original table 2, the second original O is sent from the original feeding table 22 onto the original table 2 in the same manner as described above.

When the second original O passes between the detection member 33 and the paper feed roller 31, the data corresponding to the thickness of the second original O and the thickness of the first original O are obtained. Is compared with the reference value corresponding to, and the comparison result is output to the control unit 61.

That is, when the leading edge of the second original O reaches between the detection member 33 and the paper feed roller 31, the voltage value detected by the detection circuit 73 causes the binarization circuit 111 to go to "L" level. The signal of is output. With this signal, the counter 117 starts counting clocks from an oscillator (not shown). At this time, the chip select signal of the FF circuit 113 is at "L" level, and the delay circuit 115
The digital value corresponding to the voltage value of the detection circuit 73 from the / D converter 74 is latched. On the other hand, the inverter 11
The signal inverted by 6 causes the delay circuit 114 to enter the idle state. A read signal is also supplied from the control unit 61 to the RAM 118.

When the address from the counter 117 is supplied to the RAM 118, the RAM 118 outputs the write content of the address, that is, the reference thickness data, to the read comparator 119.

Therefore, the comparator 119 has the RAM 11
By comparing the data within a predetermined range based on the thickness data of the first original document O from 8 and the thickness data of the second original document O from the delay circuit 115, When the thickness is thicker than the thickness of the second original O, the comparison result C
PR4 is set to "L" level and the thickness of the second original O is 1
If the original document O is thicker than the original document O, the comparison result CPR5
Is set to the “L” level, and when the thickness of the second original O is the same as the thickness of the first original O, the comparison result CPR6 is set to the “L” level.

As a result, the controller 61 determines that the thickness detection circuit 7
When a detection signal indicating that the thickness of the second original document O is thicker than that of the first original document O is supplied from the sixth sheet, it is determined that the second original sheet O is double-fed, and the thickness detection circuits 76 to 1 When a detection signal that the thickness of the first original O is thicker than the thickness of the second original O is supplied, it is determined that the first original O is double-fed.

When the double feed is judged, the control section 61 stops the feeding operation and outputs to the main control section 51 the fact that the double feed has occurred. As a result, the main control unit 51 guides the occurrence of double feed on the display unit 52a of the operation panel 52.

When a detection signal indicating that the thickness of the second original O and the thickness of the first original O are the same is supplied from the thickness detecting circuit 76 to the original O, the control section 61 causes the control section 61 to The second original O is scanned and discharged, and the third original O is fed from the original feed table 22 onto the original table 2 in the same manner as described above.

With respect to the third and subsequent originals, the determination of double feeding is made and processed in the same manner as described above.

Further, in the above example, when a double feed is judged,
Although the case where the feeding operation is stopped and the occurrence of the double feed is guided on the display unit 52a has been described, the number of originals before the occurrence of the double feed may be guided on the display unit 52a.

In this case, as shown in FIG. 37, the delay pulse from the delay pulse generating circuit 112 in the thickness detecting circuit 76 is supplied to the control section 61, and the memory 72 is provided with the number counting section 72a. This can be realized by the control unit 61 counting up the count value of the number counting unit 72a of the memory 72 every time the delay pulse from the delay pulse generating circuit 112 is supplied.

At the time of restart, the number counting unit 72a is cleared to "0" when the first sheet is a double feed, and when the second and subsequent sheets are a double feed, the number of sheets immediately before the double feed is held. It As a result, at the time of restart, the user
A document may be set on the document feed table 22 from the document O that has been double-fed.

With this structure, at the time of double feeding,
It is not necessary to perform the sheet feeding operation again from the first sheet, and the user can save time.

Further, when a preset signal (“L” level) is supplied from the control section 61 to the FF circuit 113 when a double feed or the like occurs during the feeding operation of a plurality of originals O, , The reference thickness data of the RAM 118 is initialized.
As a result, the thickness data for the first original O after the double feeding is canceled is stored in the RAM 118 as a reference value.

In this case, timing charts of the chip select signal with respect to the preset signal, the output of the binarization circuit 111 and the delay pulse are as shown in (a) to (d) of FIG.

By doing so, it is possible to detect the double feed for each document placed on the document feed table 22 with reference to the data of the first document O. Normally, one document (collection of originals O) has the same thickness, so if the reference data is updated for each document when there are no more documents on the original feeding table 22, various thicknesses can be obtained. Document is automatic document feeder 2
Even when set to 0, double feed can be detected.

If a preset signal from the control unit 61 is not supplied to the FF circuit 113 when a multi-feed or the like occurs during the feeding operation of a plurality of originals O, the RAM 11
The reference thickness data of No. 8 is stored in the RAM 118 as the reference value for the thickness data of the first original O before the multi-feed. Flowcharts in this case are shown in FIGS. 38 and 39.

As a result, the first original O
The double feed for can be detected immediately.

Further, the first original document O of the thickness detection circuit 86 is
Although a case has been described in which the reference thickness data for (1) is stored using the delay circuit 114, the counter 117, and the RAM 118, it may be configured by a latch circuit selected by the chip select signal.

As described above, when a double feed is detected only by the thickness data, when a photograph or the like is cut and pasted on the original O, it may be erroneously detected as a double feed.

In order to solve this problem, the case where the length data and the thickness data are combined to detect the double feed will be described below.

43 (a), (b) and (c), the normal original O, the multi-fed original O, and the original O cut and pasted on the original are detected by the detection member 33 and the paper feed roller 31. It shows the detection output detected by the length detection circuit 75 when passing through the space.

In this drawing, the thickness of the cut and pasted photograph or the like is regarded as the same as the reference document O, but the same effect can be obtained even if the thickness is different.

When the length of the normal original O is l1, the length of the multi-fed original O is l2, and the length of the original O cut and pasted on the original is l3, the length of the cut and pasted original O is , The length of the original document O is the same, but when double feeding,
Originals that are detected because they rarely completely overlap
Is longer than the reference length of the original O.

That is, l1 = l3 and l2> l1.

By utilizing this, it is also possible to detect double feeding by only detecting the length.

That is, if l1 = l3, normal paper feeding is performed. If l2> l1, double feeding is detected.

Further, by judging the conveyance state of the original O using the two kinds of detection results, even when the originals O having different lengths are mixed and fed, the double feeding and the normal feeding are accurately performed. Can be judged.

In this case, the length detecting circuit 75 (see FIG. 25)
(Refer to FIG. 34) and the thickness detection circuit 76 (refer to FIG. 34) detecting the thickness of the original O. A description will be given of an embodiment in which the conveyance state when different originals O are mixed and fed is fed. In this case, the control circuit is shown in FIG.
0, the detection circuit 73 and the control unit 61 shown in FIG.
3, a length detection circuit 75 is provided between the A / D converter 74 and the control unit 61, and a thickness detection circuit 76 is provided between the A / D converter 74 and the control unit 61.

That is, the control section 61 determines, if (thickness of reference data) <(thickness data of determination target) and (length of reference data) <(length data of determination target), the determination target document O. If (the thickness of the reference data) <(the thickness data of the determination target) and (the length of the reference data) = (the length data of the determination target), the determination target document O is cut and pasted. If it is determined that the document is a document, and (thickness of reference data) = (thickness data of determination target) and (length of reference data) = (length data of determination target), the determination target document O is a reference. It is determined that it is the same as the original O.

Here, the comparator 109 of the length detection circuit 75
The relation between each comparison result (CPR1 to 3) and each comparison result (CPR4 to 6) of the comparator 119 of the thickness detection circuit 76 is
As shown in Table 1.

[0217]

[Table 1] Therefore, the control unit 61 determines that (length of the first original O>
If the length of the second original document O) and (thickness of the first original document O> thickness of the second original document O), it is determined that the first original document O is double-fed. If (length of second original O or more> length of first original O) and (thickness of second or subsequent original O> thickness of first original O), It is determined that the second and subsequent originals O are double-fed, and (the length of the first original O>
The length of the second and subsequent originals O) and (the second and subsequent originals O
Thickness> the thickness of the first original O), it is determined that the thickness and size of the second and subsequent originals O are different (length of the second and subsequent originals O> first original O Of the original O) and (the thickness of the first original O> the thickness of the second and subsequent originals O),
It is judged that the thickness and size of the first original O are different, and (1
The length of the first original O = the length of the second and subsequent originals O) and (the thickness of the first original O> the thickness of the second and subsequent originals O)
In the case of, the first sheet is judged to be the cut and pasted original, and (the length of the first original sheet O = the length of the second and subsequent original sheets O) and (the thickness of the second and subsequent original sheets O). > (Thickness of the first original O), it is determined that the second and subsequent originals are cut and pasted originals (length of the first original O = length of the second original O and later). And (thickness of the second and subsequent originals O = thickness of the first original O), both are determined to be the reference original O.

From the above conditions, it is judged that there is an abnormality, and the conditions for stopping the paper feeding operation of the automatic document feeder 20 are only the two conditions from the top.

Therefore, the comparison result CP of the comparator 119
By the control unit 61 determining whether both R1 and CPR4 are at "L" level or the comparison results CPR2 and CPR5 of the comparator 119 are both at "L" level, the cut and pasted original O is mixed. Double feeding can be detected. If the outputs of the gate circuits 77a to 77c shown in FIG. 40 are connected to the interrupt input of the control unit 61, the load on the control unit 61 is reduced.

Further, if the comparison result CPR1 of the comparator 119 is input to the control unit 61, it is set whether the signal of the comparison result CPR1 is "L" level or "H" level when an interrupt signal is generated by double feeding. It is possible to determine whether the second sheet has been double-fed. That is, the control unit 61 may determine that the multi-feed is occurring when the OR output of the gate circuit 77c is at the "H" level.

Here, when the abnormality is canceled and the restart is performed, the data of the first original at the time of resending is updated as the reference data, or the data of the first original at the previous paper feeding is used. The control unit 61 determines whether to hold the reference data.
It can be performed depending on whether the signal of the comparison result CPR1 is at "L" level or "H" level.

That is, the control section 61 controls the comparison result CPR.
When it is determined that the first signal is double-fed from the L signal level, the reference data stored in the latch circuit 106 in the length detection circuit 75 and the R data in the thickness detection circuit 76 are detected.
Rewriting of the first retransmitted original O for the reference data stored in the AM 118 is determined. As a result, the reference data is rewritten using the first original O that is retransmitted, and then the other original O is updated using the reference data.
Compare length and thickness.

Further, when the control section 61 determines that the signal of the comparison result CPR1 is from the H "level and it is not the double feeding of the first original, the latch circuit 106 in the length detection circuit 75 is detected.
It is determined whether the reference data stored in the RAM and the reference data stored in the RAM 118 in the thickness detection circuit 76 are held. As a result, the length and thickness of the retransmitted document O are compared using the reference data.

Flowcharts for the above case are shown in FIGS.

In the above example, the binarization circuit, the delay pulse generation circuit, the inverter circuit, and the FF circuit in the length detection circuit 75 and the thickness detection circuit 76 can be used in common. You may comprise only one.

Next, in the case where originals O having different sizes are mixed and fed, the thickness of the original O is shown in FIGS. ), The thickness of the original O may differ from that of the original O (see (a) of FIG. 43). An embodiment in which the peak detection circuit for detection is used to prevent the occurrence will be described. FIG. 43B shows a case where the document O is double-fed.
FIG. 43C shows the case of the cut and pasted original O. Although the case where the thickness of the paper to be attached is the same as that of the mount has been described, other thicknesses may be used.

That is, as shown in FIG. 44, a peak detection circuit 78 is provided between the A / D converter 74 and the thickness detection circuit 76 in the circuit of FIG. The value is supplied and the thickness detection circuit 76
A binarization signal from the binarization circuit 111 of the counter 117
A count output (a signal obtained by dividing the master clock) from which bit of is also supplied. The binarized signal and the count output may be supplied from the binarization circuit 101 and the counter 104 of the length detection circuit 75.

However, the master clock itself input to the counter 117 may be input as a divided value.

The peak detection circuit 78 detects the peak value of the digital value from the A / D converter 74 to determine the maximum value of the thickness data for each original O as the thickness detection circuit 7.
6 is output.

For example, as shown in FIG. 45, gate control circuits 121 and 122, delay circuits 123 and 124, latch circuits 125 and 126, a comparator 127, and a selector 12.
8, an inverter 129, and an inverter 130.

That is, as shown in FIG. 46 (a),
The binarized signal from the binarization circuit 111 is supplied to the gate control circuits 121 and 122, and the digital value from the A / D converter 74 is passed through delay circuits 123 and 124 to latch circuits 125 and 126, respectively. Latch clock A (see (b) of FIG. 46) as a counter output from the counter 117 is directly supplied to the latch circuit 125.
A latch clock B (see (c) of FIG. 46) obtained by inverting the counter output by the inverter 129 is supplied to the latch circuit 126.

The gate control circuits 121 and 122 are operable when the binarized signal from the binarization circuit 111 is at "L" level, and the original O is supplied to the detection member 33. The operation is performed only when it exists between the paper rollers 31. At this time, the gate control circuit 121,
122 opens the gates of the delay circuits 123 and 124, respectively.

In the operable state, the gate control circuit 121 outputs the operation stop signal S1 from the comparator 127.
When (“H” level) is supplied, the latch circuit 125
The gate is closed and the latch contents are retained.
In the operable state, the gate control circuit 122 closes the gate of the latch circuit 126 and holds the latch contents when the operation stop signal S2 (“H” level) is supplied from the comparator 127. .

The latch circuit 125 latches the digital value (thickness data) from the delay circuit 123 when the latch clock A rises when the gate is opened by the gate control circuit 121. The latch contents are output to the comparator 127 and the selector 128.

The latch circuit 126 is designed to latch the digital value (thickness data) from the delay circuit 124 when the latch clock B rises when the gate is opened by the gate control circuit 122. The latch contents are output to the comparator 127 and the selector 128.

The comparator 127 compares the latch content A of the latch circuit 125 with the latch content B of the latch circuit 126, and the latch content A of the latch circuit 125 is the latch content 12.
6 is larger than the latch content B of 6 (A> B), the operation stop signal S1 is output to the gate control circuit 121, and the latch content B of the latch circuit 126 is larger than the latch content A of the latch circuit 125 (B ≧ A). The operation stop signal S2 is output to the gate control circuit 122. The above comparator 1
The operation stop signal S2 output from 27 is the inverter 13
It is supplied to the selector 128 via 0 as a selection signal.

When the selection signal supplied from the comparator 127 through the inverter 130 is at "H" level, the selector 128 outputs the latch content A from the latch circuit 125 to the thickness detection circuit 76, and the selection signal is In the case of the "L" level, the latch content B from the latch circuit 126 is output to the thickness detection circuit 76.

Next, the operation in such a configuration will be described.

First, when the leading edge of the original O is sandwiched between the detection member 33 and the paper feed roller 31, the voltage detected by the detection circuit 73 is input to the delay circuits 123 and 124. The latch circuits 125 and 126 are configured to latch the outputs of the delay circuits 123 and 124 when the latch clocks A and B rise, respectively.

Therefore, as shown in FIG. 46B, the output of the delay circuit 123 is first latched by the latch circuit 125 by the latch circuit 125.

At this time, since the latch circuit 126 does not operate, the output becomes "0".

Thereafter, the outputs of the latch circuits 125 and 126 are compared by the comparator 127. Latch circuit 12
Since the output of 6 is “0”, the comparator 127 does not supply the operation stop signal to the gate control circuit 122 (“L” level). At this point, the gate control circuit 122
Becomes a state in which the latch circuit 126 receives the output from the delay circuit 124.

On the other hand, from the comparator 127 to the gate control circuit 1
Since the operation stop signal (“H” level) is supplied to 21, the gate control circuit 121 sends the operation stop signal to the latch circuit 125. Therefore, the latch circuit 125 holds the first sampled data as it is.

Since the selector 128 is supplied with the "H" level as a selection signal, the latch content A of the latch circuit 125 is output to the thickness detection circuit 76.

Next, when the latch clock B rises, since only the latch circuit 126 is operating, the second sampled data is latched by the latch circuit 126. Here, the data latched in the latch circuit 126 and the data latched in the latch circuit 125 are again compared by the comparator 127.

At this time, when the latch data A of the latch circuit 125 is larger than the latch data B of the latch circuit 126 (A> B), the latch data A is again the latch data 12.
5, the latch circuit 126 latches the data from the delay circuit 124 at the next rise of the latch clock B.

Further, the latch data A of the latch circuit 124
Is smaller than the latch data B of the latch circuit 126 (A ≦ B), the comparator 127 does not supply the operation stop signal to the gate control circuit 121 (“L” level). As a result, the gate control circuit 121 enters a state in which the latch circuit 125 can latch the data from the delay circuit 123.

On the other hand, from the comparator 127 to the gate control circuit 1
Since the operation stop signal (“H” level) is supplied to the gate 22, the gate control circuit 122 sends the operation stop signal to the latch circuit 126. Therefore, the latch circuit 126 holds the second sampled data as it is.

Further, since the "L" level is supplied to the selector 128 as the selection signal, the latch content B of the latch circuit 126 is output to the thickness detection circuit 76.

In this way, the sampled data and the data before it are compared, and the larger data is held.

Finally, when the latch data held in the latch circuits 125 and 126 is larger than the latch data A (A ≧ B), the latch data A is output to the thickness detecting circuit 76. . If the latch data A is smaller than the latch data B (A <B), the latch data B is output to the thickness detection circuit 76.

In this circuit configuration, the larger detection result of both latch circuits 125 and 126 is sequentially output to the thickness detection circuit 76. Finally, the maximum value of the whole one original O is stored in the delay circuit 114 of the thickness detection circuit 76, the address is determined by the control of the control unit 61, and then stored in the RAM 118.

With such a configuration, even if the sizes of the originals O are different, it is possible to accurately detect the conveyance state of the originals O without erroneously detecting a double feed.

Further, when the peak detection circuit is not provided, the thickness detection is not always sampled at the time when it shows the maximum value. However, considering the discrimination condition by the combination of thickness and length, The determination may be made as shown in Table 2.

[0255]

[Table 2] The length can be accurately detected. Therefore, Condition 1 and Condition 4, or Condition 6 and Condition 9 cannot be detected separately depending on the detection timing of the thickness.

However, in general, when the size of the original document O is different in one document, there is almost no case, so condition 4 is satisfied.
If the sheet feeding operation is stopped under the condition 6 above, there will be no problem even if double feeding is performed.

Therefore, the effective conveyance state of the original O can be detected by the combination of the thickness and the length without using the thickness peak detection circuit.

When the thickness of one original document O such as the cut and pasted original document O is different, the thickness of each original document O is sampled a plurality of times and compared to determine the peak detection circuit. It is possible to accurately detect the conveyance state of the document O even without the presence of the sheet.

In FIG. 34, the address generating counter 117 starts from "0" and starts counting when the leading edge of the first original O is detected.

The address generating counter 117 generates an address in synchronization with the counter operation, and thereby R
The data of the thickness of the first original O is sequentially stored in the AM 118.

For the second and subsequent originals O, the detected thickness data is stored in the delay circuit 114 and output to the comparator 119. At this time, the RAM is read at the same timing as the sampling timing of the first sheet from the leading edge of the original O.
The comparator 119 compares the thickness data of the first original O with the data of the thickness of the second original O output from 118.

FIG. 4 is a timing chart for sampling the first original O and the second and subsequent originals O.
7 (a) to (c).

The respective comparison results thus sampled a plurality of times are stored in the memory 72 by the control section 61 as the output of the thickness detection circuit 76.

FIG. 48 shows the comparison result of the data detected at each timing.

A is a reference original O without cut and paste, b is a reference original O cut and pasted, c and c ′ are double feed, and the two originals O are misaligned. d shows a case where the leading ends are aligned with each other by double feeding.

Here, the comparison results according to the sampling timing are shown in (1) to (10) of Table 3.

[0267]

[Table 3] From FIG. 48 and Table 3 above, for example, when the first sheet is a cut and pasted document such as b, when the second sheet is multi-fed like c ′, in the sampling of (1), b> c ′ However, b = c ′ in other sampling.

When such sampling values having different thicknesses exist, it is judged from the length data that the longer original O is multi-fed.

Therefore, for the update of the reference data after the detection of the double feed, it is sufficient to always select the shorter one.

By the way, in the case of double-feeding, in some rare cases, the leading ends are aligned and a plurality of originals O are overlapped.

At this time, in the conventional method, since the length is the same as the reference document O, there is a risk that it may be judged as a cut and pasted document.

Here, paying attention to each sampling data, in all the sampling data, the thickness data is equal or large when the leading ends are aligned and double-fed.

By utilizing this fact, such an original O
It is also possible to detect the case where all of them are fed in duplicate.

The more specific detection method is as follows.

(1) Store a plurality of comparison results in the memory 72.

(2) The AND output of the thickness comparison results is calculated.

The output of the comparator in one sampling is shown in Table 4 below.

[0278]

[Table 4] Here, when the AND output is taken, it can be seen that the outputs shown in Table 5 below appear only when all the comparison results are the same.

Therefore, all thickness comparison results are

[0280]

[Table 5] Becomes

(3) Therefore, if the above three types of comparison results are output, the 1.1th sheet is double-fed. → Feeding operation stopped 2. The second and subsequent sheets are being double fed. → Stop feeding operation 3. Base original O or cut-and-pasted original for the first and second sheets → To the next feeding operation (4) If one of the comparison results is different from the others, the length is different. From the data 4-1 If the length of the first sheet> the length of the second sheet or later> The first sheet is double-fed → stop the paper feeding operation 4-2 If the length of the first sheet <the length of the second sheet or later For example, double feed on the second and subsequent sheets → stop feeding operation 4-3 If the length of the first sheet = the length of the second and subsequent sheets, the first or second sheet is cut and pasted Here, as in 4-3 Even if the lengths are the same, if the leading edges are aligned and double-fed, detection can be performed as in (3), and there is no risk of erroneous detection.

49, 50, and 51 are flowcharts of the judgments when a plurality of comparisons are made in one original O as described above.
Shown in.

The number counting unit 72a is cleared to "0" when the first sheet is double fed, and when the second and subsequent sheets are double fed, the number of sheets immediately before the double feeding is held. This allows
At the time of restart, the user may set a document on the document feed table 22 from the document O that has been double-fed.

The following effects can be expected by storing only the minimum thickness data in one original O only when the reference data is stored in the RAM 118 in the thickness detection circuit 76.

An embodiment in this case will be described below.

As shown in FIG. 52, the delay circuit 1 of FIG.
This can be realized by providing a minimum value detection circuit 121 between the RAM 14 and the RAM 118.

The minimum value detection circuit 121 has the same structure as the peak detection circuit 78 shown in FIG. 45.
The timing of each part shown in is also the same. However, the latch circuit 126 is configured to be held in a high impedance state, that is, "FF" by a pull-up resistor, and the meanings of the operation stop signals S1 and S2 are different. Specifically, the comparator 127 includes the latch circuit 1
25 latch contents A and latch circuit 126 latch contents B
And the latch content A of the latch circuit 125 is larger than the latch content B of the latch circuit 126 (A> B),
When the operation stop signal S2 is output to the gate control circuit 122 and the latch content B of the latch circuit 126 is larger than the latch content A of the latch circuit 125 (B ≧ A), the operation stop signal S
1 is output to the gate control circuit 121. Thus, A> B, B ≧ A and the operation stop signals S1 and S2
The configuration is the same as that of the peak detection circuit by reversing the contrast of the above.

Next, the operation in such a configuration will be described.

First, when the leading edge of the original O is sandwiched between the detection member 33 and the paper feed roller 31, the voltage detected by the detection circuit 73 is input to the delay circuits 123 and 124. The latch circuits 125 and 126 are configured to latch the outputs of the delay circuits 123 and 124 when the latch clocks A and B rise, respectively.

Therefore, as shown in FIG. 46B, the output of the delay circuit 123 is first latched by the latch circuit 125 by the latch circuit 125.

At this time, the latch circuit 126 is in a high impedance state, that is, "F" by the pull-up resistor.
It is F ".

Thereafter, the outputs of the latch circuits 125 and 126 are compared by the comparator 127. Latch circuit 12
Since the output of 6 is “FF”, the comparator 127 does not supply the operation stop signal to the gate control circuit 122 (“L” level). At this point, the gate control circuit 122
Becomes a state in which the latch circuit 126 receives the output from the delay circuit 124.

On the other hand, from the comparator 127 to the gate control circuit 1
Since the operation stop signal (“H” level) is supplied to 21, the gate control circuit 121 sends the operation stop signal to the latch circuit 125. Therefore, the latch circuit 125 holds the first sampled data as it is.

Since the selector 128 is supplied with the "H" level as a selection signal, the latch content A of the latch circuit 125 is output to the thickness detection circuit 76.

Next, when the latch clock B rises, only the latch circuit 126 is operating, so that the second sampled data is latched by the latch circuit 126. Here, the data latched in the latch circuit 126 and the data latched in the latch circuit 125 are again compared by the comparator 127.

At this time, when the latch data A of the latch circuit 125 is smaller than the latch data B of the latch circuit 126 (A ≦ B), the latch data A is again the latch data 12
5, the latch circuit 126 latches the data from the delay circuit 124 at the next rise of the latch clock B.

The latch data A of the latch circuit 124
Is larger than the latch data B of the latch circuit 126 (A> B), the comparator 127 does not supply the operation stop signal to the gate control circuit 121 (“L” level). As a result, the gate control circuit 121 enters a state in which the latch circuit 125 can latch the data from the delay circuit 123.

On the other hand, from the comparator 127 to the gate control circuit 1
Since the operation stop signal (“H” level) is supplied to the gate 22, the gate control circuit 122 sends the operation stop signal to the latch circuit 126. Therefore, the latch circuit 126 holds the second sampled data as it is.

Since the selector 128 is supplied with the "L" level as the selection signal, the latch content B of the latch circuit 126 is output to the thickness detecting circuit 76.

In this way, the sampled data is compared with the data before it, and the smaller data is held.

Finally, when the latch data held in the latch circuits 125 and 126 is such that the latch data A is smaller than the latch data B (A ≦ B), the latch data A is output to the thickness detecting circuit 76. . When the latch data A is larger than the latch data B (A> B), the latch data B is output to the thickness detection circuit 76.

With such a structure, even if the sizes of the originals O are different, it is possible to accurately detect the conveyance state of the originals O without erroneously detecting a double feed.

FIG. 53 shows the conveyance state of the document O and the detection point of the minimum value.

With such a configuration, the minimum value of the first original document O serving as a reference serves as a reference for determining the data of the second and subsequent sheets. In this case, when the thickness of the first sheet is larger than the thickness of the second sheet and thereafter, the first sheet is limited to the case where the sheet is double-fed.

Therefore, even if the lengths of the second and subsequent originals O are not detected, the paper feeding operation is immediately performed at the time when it is detected that the thickness of the first sheet is larger than the thickness of the second and subsequent sheets. You can stop.

Further, even when the leading edge of the first original O is double-fed, accurate detection can be performed without combining with the length data.

The above-mentioned discrimination method is shown in Table 6 below.

[0308]

[Table 6] Flow charts in this case are shown in FIGS. 54 and 55.

Further, the minimum value may be detected when detecting both the first and second and subsequent data. An example of this case will be described below.

As shown in FIG. 53, the thicknesses of the first and second sheets are different only when the originals O are completely overlapped with each other and the sheets are double fed.

Therefore, the determination may be made as follows.

(1) Thickness of the first sheet> thickness of the second sheet and thereafter →
Double feed of the first sheet Stops feeding operation (2) Thickness of the first sheet <thickness of the second and subsequent sheets → Double feed of the second and subsequent sheets Stops feeding operation (1) Thickness of the first sheet = 2 Thickness after the first sheet (a) Length of the first sheet> Length after the second sheet → Double feeding of the first sheet Feeding operation stopped (b) Length of the first sheet = Length after the second sheet → Both are base original O or cut and pasted original (C) Length of the first sheet <length of the second and subsequent sheets → double feed of the second and subsequent sheets If such a determination method is used, the first sheet or the second sheet Even after the eyes, double feeding can be discriminated even when the tips are completely overlapped.

At this time, it is not necessary to refer to the length data.

FIG. 56 shows a schematic block diagram for detecting the minimum value when detecting both the first and second and subsequent data. In this case, the delay circuit 114 of FIG.
And a minimum value detection circuit 121 between the RAM 118 and
This can be realized by providing the minimum value detection circuit 122 between the delay circuit 115 and the comparator 119.

FIG. 57 is a flow chart of the discrimination method.
It shows in FIG.

If the shape of the original O to be inserted into the automatic original feeder 20 is known in advance,
It is not necessary to store the data of the first sheet in the storage means and compare them.

Specifically, the document O to be fed is a slip, securities, or the like.

In such a case, the reference data is held in the storage means (eg, ROM) which holds the data even when the power of the apparatus is turned off, and the reference data stored in the ROM and the fed document O are stored. By comparing the data, it is possible to determine the paper feed state.

First, the thickness detection circuit 76 when the size of the original O to be fed is fixed will be described.

As shown in FIG. 59, the thickness detecting circuit 76 includes a binarizing circuit 131, a delay circuit 132, an inverter 133, an address generating counter 134, and a ROM 13.
5 and a comparator 136.

According to this structure, when the leading edge of the original O reaches between the detection member 33 and the paper feed roller 31, the binarization circuit 13 uses the voltage value detected by the detection circuit 73.
1 outputs an "L" level signal. With this signal,
The counter 134 starts counting clocks from an oscillator (not shown). Further, the delay circuit 132 latches the digital value from the A / D converter 74 corresponding to the voltage value of the detection circuit 73. Then, when the address from the counter 134 is supplied to the ROM 135, the ROM 135 outputs the write content of the address, that is, the reference thickness data, to the read comparator 136.

Therefore, the comparator 136 has the ROM 13
By comparing the data within a predetermined range based on the reference thickness data from No. 5 with the thickness data of the document O from the delay circuit 131, for example, as shown in Table 7, the thickness of the document O is used as a reference. If it is thicker than the thickness, the comparison result CPR4 is set to "L" level, and if the thickness of the document O is thicker than the reference thickness, the comparison result CPR5 is set to "L" level and the document O is set.
, The comparison result CPR6 is set to "L" level.

[0323]

[Table 7] As a result, the control unit 61 causes the thickness detecting circuit 76 to detect the original O.
When a detection signal that the thickness of the original O is thinner than the reference thickness is supplied, it is determined that different types of originals O are conveyed, and the thickness detection circuit 76 detects the detection signal that the thickness of the original O is thicker than the reference thickness. When the document is supplied, it is determined that the document O is double-fed.

When it is judged that this multi-feed or the conveyance of the original O of a different type, the control section 61 stops the feeding operation,
The fact that double feed has occurred is output to the main control unit 51. As a result, the main control unit 51 guides the occurrence of double feeding or the conveyance of different types of originals O on the display unit 52a of the operation panel 52.

Further, when the detection signal that the thickness O of the original O is the same as the reference thickness is supplied from the thickness detection circuit 76, the control section 61 causes the original scanning of the original O and the paper discharge processing. At the same time, the next original O is fed from the original feed table 22 onto the original table 2 in the same manner as described above.

The control section 61 may stop the sheet feeding operation as a conveyance error when the thickness detection circuit 76 supplies a signal indicating that the thickness of the original document O and the reference thickness do not match.

In the thickness detecting circuit 76 of the above example, the ROM is used for storing the reference thickness data, but the thickness reference data may be set by a dip switch or a rotary switch instead. FIG. 60 shows a schematic block diagram in this case. In this case, the binarization circuit 131, the delay circuit 132, the DIP switch 140, and the comparator 13
It is composed of six.

Next, the length detection circuit 75 when the size of the original O to be fed is fixed will be described.

As shown in FIG. 61, the length detecting circuit 75 includes a binarizing circuit 141, a delay pulse generating circuit 142,
Inverter 143, counter 144, dip switch (or rotary switch) 145, latch circuit 14
6 and a comparator 147. The DIP switch 145 stores length data of a predetermined size.

That is, when the leading edge of the original O reaches between the detection member 33 and the paper feed roller 31, the binarization circuit 141 outputs an "L" level signal according to the voltage value detected by the detection circuit 73. To do. With this signal, the counter 144
Starts counting with a clock from an oscillator (not shown). At this time, the count result of the counter 144 is latched in the latch circuit 146.

When the trailing edge of the original O passes between the detection member 33 and the paper feed roller 31, the binarization circuit 141 outputs an "H" level signal according to the voltage value detected by the detection circuit 73. Output. The signal polarity of this signal is inverted by the inverter 143 and becomes "L" level, which is input to the clear terminal of the counter 144. Since this terminal is valid at the "L" level, the counter 144 is cleared by the input of the "L" level signal.

The output of the inverter 143 is the latch circuit 14
6 is also used for the latch clock, and the latch circuit 146 latches the output value of the counter 144 immediately before clearing at the falling edge of the latch clock. As a result, the latch circuit 146
In, the number of clocks corresponding to the original O is stored.

Accordingly, the comparator 147 compares the count value corresponding to the reference length from the DIP switch 145 with the count value corresponding to the length of the document O from the latch circuit 146, and, for example, the table As shown in 8, when the length of the document O is longer than the reference length, the comparison result CPR
If the length of the original O is longer than the reference length, the comparison result CPR2 is set to "L" level, and if the length of the original O is the same as the reference length, the comparison result CPR3.
To "L" level.

[0334]

[Table 8] As a result, the control unit 61 causes the length detection circuit 75 to send the document O.
When a detection signal that the length of is shorter than the reference is supplied,
The length detection circuit 7 determines whether or not different types of originals O are conveyed.
When a detection signal that the length of the original O is longer than the reference is supplied from 5, it is determined that the first original O is double-fed.

When it is determined that the multi-feeding or the conveyance of the originals O of different types is determined, the control section 61 stops the feeding operation,
The fact that double feed has occurred is output to the main control unit 51. As a result, the main control unit 51 guides the occurrence of double feeding or the conveyance of different types of originals O on the display unit 52a of the operation panel 52.

When a detection signal indicating that the length of the original O is the same as the reference length is supplied from the length detection circuit 75, the control section 61 causes the original scanning of the original O and the discharge processing. At the same time, the next original O is fed from the original feed table 22 onto the original table 2 in the same manner as described above.

The control unit 61 may stop the paper feeding operation as a conveyance error when the length detection circuit 75 supplies a signal indicating that the length of the document O and the reference length do not match.

In the above example, the dip switch or the rotary switch is used to store the reference length data, but the length reference data may be set in the ROM instead. When a ROM is used, reference data of lengths corresponding to a plurality of types of sizes may be stored and switched and set. FIG. 60 shows a schematic block diagram in this case. That is, as shown in FIG. 62, the length detecting circuit 75 includes a binarizing circuit 151 and a delay pulse generating circuit 15.
2, inverters 153, 154, counter 155, RO
It is composed of an M156, a latch circuit 157, and a comparator 158.

When one kind of reference data of length is stored in the ROM 156, the delay pulse from the delay pulse generation circuit 152 is inverted by the inverter 154 after the length data of the document is latched by the latch circuit 157. The signal causes the ROM 156 to operate, and the reference data of a predetermined size stored in the ROM 156 is output to the comparator 158. Other operations are the same as in the case of FIG.

When the ROM 156 stores reference data of plural kinds of lengths, the delay pulse generation circuit 1
When a signal obtained by inverting the delayed pulse from the inverter 52 by the inverter 154 is supplied, the address in which the reference data of the length corresponding to the size instructed by the operation panel 52 is stored is input to the ROM 156, and the address corresponding to the address is input. The data is read and output to the comparator 158. Other operations are shown in FIG.
It is similar to the case of. Next, an embodiment in which the size of the fed document O is detected by using different voltage values output by the detection circuit 73 according to the change in the resistance value of the pressure-sensitive conductive rubber 33b in the detection member 33 will be described. explain.

As can be seen from the equivalent circuit shown in FIG. 63, the total resistance value R of the pressure-sensitive conductive rubber 33b is as follows depending on the size of the original O to be fed.

(1) When A5 horizontal / A4 vertical original O is sandwiched between the detection member 33 and the paper feed roller 31 1 / R = 1 / R1 + 1 / R2 + 1 / R3 + 1 / Rn-2
+ 1 / Rn-1 + 1 / Rn + (1 / R'4 + ... + 1 /
R'n-3) (2) When the document O of B5 horizontal / B4 vertical is sandwiched between the detection member 33 and the paper feed roller 31 1 / R = 1 / R1 + 1 / R2 + 1 / Rn-1 + 1 / Rn
+ (1 / R'3 + ... + 1 / R'n-2) (3) When the A4 horizontal / A3 vertical original O is sandwiched between the detection member 33 and the paper feed roller 31 1 / R = 1 / R1 + 1 / Rn + (1 / R'2 + 1 / R '
3 + ... + 1 / R'n-1) Therefore, when the type of the original O is known in advance, the output of the comparator corresponding to the size of the original O is stored as table data in a non-volatile storage means such as a ROM.
The size of the original O can be discriminated by storing the original O and the output of the comparator when the original O is fed. An example of this table data is shown in FIG. The output of the comparator according to the size of the original O when the original O is fed without double feeding is as follows: (1) A5 horizontal or A4 vertical original O is sandwiched between the detection member 33 and the paper feed roller 31. Case → a (2) When the original document O of B5 horizontal or B4 vertical is sandwiched between the detection member 33 and the paper feed roller 31 → b (3) The original O of horizontal A4 or A3 vertical is detected by the detection member 33 and the paper feed roller 31 When it is sandwiched between, → c.

In the case of double feeding, the thickness of the original O is
The output appearing in the comparator is doubled. (1) When an A4 horizontal or A3 vertical original O is sandwiched between the detection member 33 and the paper feed roller 31 → a2 (2) B5 horizontal or B4 vertical original O When it is sandwiched between the detection member 33 and the paper feed roller 31 → b2 (3) When an A5 horizontal or A4 vertical document O is sandwiched between the detection member 33 and the paper feed roller 31 → c2.

Therefore, it is possible to realize the detection of the double-feed and the size detection by the same detection mechanism.

The determination result of the length may be used for the determination of A4 landscape or A3 portrait, the determination of B5 landscape or B4 portrait, and the determination of A5 landscape or A4 portrait.

Using the thickness detection circuit 76 shown in FIG. 59,
A case of implementing the above embodiment will be described.

However, in the ROM 135, reference thickness data corresponding to each size is stored for various counter values, and reference data for each size is output according to the count output of the counter 134. It is supposed to be done.

For example, in the ROM 135, the reference data corresponding to the A5 horizontal or A4 vertical original O, the reference data corresponding to the B5 horizontal or B4 vertical original O, and the reference data corresponding to the A4 horizontal or A3 vertical original O And reference data for double feeding are stored.

According to this structure, when the leading edge of the original O reaches between the detection member 33 and the paper feed roller 31, the binarization circuit 13 uses the voltage value detected by the detection circuit 73.
1 outputs an "L" level signal. With this signal,
The counter 134 starts counting clocks from an oscillator (not shown). Further, the delay circuit 132 latches the digital value corresponding to the voltage value from the detection circuit 73 from the A / D converter 74.

When various addresses are supplied from the counter 134 to the ROM 135, the ROM 135 reads the write contents of these addresses, that is, the reference data for each size, and outputs the read reference data to the comparator 136.

Therefore, the comparator 136 has the ROM 13
By comparing the data within the predetermined range based on the reference data for each size from 5 and the data of the original O from the delay circuit 132, for example, as shown in Table 9, in the case of the original O of A5 landscape or A4 portrait , Comparison result CPR4 is “L”
When the original O is set to level B5 horizontal or B4 vertical, the comparison result CPR5 is set to "L" level and A4 horizontal or A4.
In the case of a three-orientation original O, the comparison result CPR6 is set to the "L" level, and in the case of double feeding, all the comparison results CPR4, 5,
6 is set to "H" level.

[0352]

[Table 9] As a result, when the thickness detection circuit 76 supplies the "L" level as the comparison result CPR4, the control unit 61 determines whether the document O of A5 landscape or A4 portrait is fed, and the thickness detection circuit 76 compares it. When the "L" level is supplied as the result CPR5, it is determined whether or not the document O of B5 landscape or B4 portrait is fed, and when the "L" level is supplied as the comparison result CPR6 from the thickness detection circuit 76, the A4 landscape is supplied. Alternatively, when it is judged that the document O of A3 vertical size is fed and the “H” level is supplied as the comparison results CPR 4, 5, and 6 from the thickness detection circuit 76,
The double feeding of the original O is judged, and the feeding operation is stopped.

Further, as shown in FIG. 65, each comparison result CPR4 of the comparator 136 is added to the thickness detection circuit 76 of FIG.
An AND circuit 137 which takes AND of 5 and 6 and outputs an error detection signal may be added. In this case, the control unit 61 determines the double feeding of the document O according to the error detection signal from the AND circuit 137 in the thickness detection circuit 76,
Stop the feeding operation.

Further, in order to detect the double feeding for each size, as shown in FIG. 66, instead of the comparator 136 and the AND circuit 137 of FIG. 65, the comparator 138 and the NAND circuit 1 are provided.
39a, 139b, 139c, and 139d may be used. This comparator 138 outputs a signal at the "L" level of the c terminal as a comparison result in the case of the normal feeding of the original O of A4 landscape or A3 portrait, and in the case of the double feeding of the document O of A4 landscape or A3 portrait. As a comparison result, an “L” level signal of the c2 terminal is output, and in the case of normal feeding of an original O of B5 landscape or B4 portrait, a “L” level signal of the b terminal is output as a comparison result and the B5 landscape or In case of multi-feed of B4 portrait original O,
As a comparison result, an “L” level signal of the b2 terminal is output, and in the case of normal feeding of an original O of A5 landscape or A4 portrait, as a comparison result, an “L” level signal of the a terminal is output and A5 is output.
In the case of double feeding of the original O in the horizontal direction or the A4 vertical direction, the "L" level signal of the a2 terminal is output as the comparison result.

The NAND circuit 139a outputs the NAND results of the comparison results a and a2 terminals from the comparator 138, and the NAND circuit 139b outputs the comparison results b and b2 terminals of the comparator 138 to the NAND circuit 139c. Is the comparator 13
The NAND circuit 139d outputs the NAND result of the comparison result c and the c2 terminal from 8 and outputs the NAND of the a2 terminal output, the b2 terminal output, and the c2 terminal output as the comparison result from the comparator 138. . NAND circuit 139a, 1
Outputs 39b, 139c, and 139d are comparison results CPR
It is output to the control unit 61 as 4 to 7.

Table 10 shows the relationship between the comparison results CPR 4 to 7 and the feeding state of the original O.

[0357]

[Table 10] As described above, the size of the document O depends on the width of the document O.
It can be roughly classified into three types.

Therefore, by detecting the length of the document O, it is possible to determine whether it is A4 landscape or A3 portrait, B5 landscape or B4 portrait, or A5 landscape or A4 portrait.

For example, when the control section 61 discriminates the size group of the original O from the comparison result from the thickness detection circuit 76 (width detection circuit) shown in FIGS.
ROM of control unit 61 to length detection circuit 75 shown in FIG.
By selecting the data table of 156 (that is, selecting the address in the ROM 156 for each size group), the size of one of the size groups can be determined from the comparison result CPR1 obtained from the comparator 158.

Since the comparator 158 has already detected the size in the width direction, the output of the comparison result CPR1 is: For A4 landscape or A3 portrait documents → If A4 landscape,
"H" level, if A3 portrait, "L" level, For B5 landscape or B4 portrait documents → If B5 landscape,
2. "H" level, if B4 vertical, set to "L" level, For A5 landscape or A4 portrait → If A5 landscape, set to "H" level, and if A4 portrait, set to "L" level.

By reading this by the control unit 61,
The size can be determined.

Further, it is possible to detect double feeding from the length detection data.

For example, the original O fed by the thickness detecting circuit 76 as the width detecting circuit shown in FIGS.
Suppose that it is possible to determine that is a size-based group of 1. Here, the output stored in the latch circuit 146 is A4.
After the length is determined to be the above, if the data becomes smaller than A3, the comparison result CPR2 of the comparator 158 is set to the “L” level. As a result, the control unit 61 causes the comparison result CP
The double feeding is determined by R2, and the paper feeding operation is stopped.

FIG. 67, FIG. 68, and FIG. 69 are flow charts of the method of detecting double feeding which also serves for size detection.

Further, the size of the original O can be detected only by the data of the length detecting circuit 75.

FIG. 70 shows a schematic block diagram of the length detection circuit 75 in this case.

As in this embodiment, A4 width, A3, B
In the case of discriminating between 6 types of 5 horizontal, B4, A5 horizontal, and A4, the length of each original O size is as follows.

A4 width: 210 mm A3: 420 m
m B5 width: 176 mm B4: 350 mm A5 width: 148 mm A4
: 297 mm Therefore, the data corresponding to this length is stored in the ROM 156 as table data. Also, ROM15
The address of 6 is incremented at regular intervals, the data of the original document corresponding to the address is output, and the read data may be compared with the comparator 158.

Here, as shown in Table 11, the comparator 158 compares the comparison result CPR1 when the length of the document O is A5 horizontal.
To “L” level and the length of the original O is B5 horizontal,
When the comparison result CPR2 is set to the "L" level and the length of the original O is A4 horizontal, the comparison result CPR3 is set to the "L" level, and when the length of the original O is A4 vertical, the comparison result CPR4 is set.
To “L” level and the length of the original O is B4 vertical,
The comparison result CPR5 is set to "L" level, and when the length of the document O is A3 vertical, the comparison result CPR6 is set to "L" level.

[0370]

[Table 11] The comparison results CPR1 to CPR6 of the comparator 158 are transferred to the control unit 61.
It is possible to determine the size of the original O.

As described in the embodiment of the width detection data, if all the comparison results CPR1 to CPR6 of the comparator 158 are set to the "H" level when data other than the predetermined size is detected, the double feed is performed. Can also be detected.

Before use, the user may insert the original O to be actually used into the automatic original feeder 20 and store it as reference data in a storage means backed up by a battery.

Since the thickness of the original O used varies, the output from the pressure-sensitive conductive rubber 33b in the detection member 33 may differ depending on the size. Further, the document O inserted into the automatic document feeder 20 is not always the standard size. In such a case, it is difficult for the user to rewrite the ROM data because a dedicated tool is required. Therefore, if the user stores the data of the document O actually used in the non-volatile storage means, the above-mentioned problem can be solved.

71 and 72 are schematic block diagrams of an embodiment of the thickness detecting circuit 160 in this case. The thickness detection circuit 160 includes delay circuits 161, 162, an inverter 1
63, counter 164, RAM 165, battery 16
6 and a comparator 167.

First, when the user inputs the data of the document O, the size of the document O is selected by the operation panel 52. FIG. 73 shows a display example of the display unit 52a when selecting. The display unit 52a has a built-in input unit such as a touch sensor.

By the input of the input mode switching key 52d, the control section 61 of the automatic document feeder 20 switches to the data input mode. Then, the main control unit 51 displays the display unit 52.
At a, a document size input screen as shown in FIG. 73 is displayed.

If the data of the original O of a standard size is registered as the reference data, each standard size is selected. In the case of a special custom size, the custom size 1 to
Select 4.

With this selection, the control unit 61 causes the display unit 5 to
The counter 164 generates an address corresponding to the size information designated by 2a.

Next, the original document O serving as a reference is fed by the paper feeding operation.
Before detecting the start signal, the control unit 61 sets the start signal to "H".
Level. At this time, the chip select signal of the delay circuit 161 becomes "L" level by the inverter 163. On the other hand, the chip select signal of the delay circuit 162 is
Since it is at the “H” level, the delay circuit 161 is in an operable state and the delay circuit 162 is in a dormant state.

Here, when the automatic document feeder 20 is in the ready state, the main control section 51 displays the display section 52a, as shown in FIG.
As shown in, a reference document O insertion guide screen is displayed.

When the original O is detected by the empty sensor 29, the control unit 61 starts the feeding operation, and the original O serving as the reference is fed in the feeding direction via the registration roller pair composed of the aligning rollers 34 and 35. Is fed to the lower surface side of the document transport belt 37 that is running.

When the reference original O passes between the paper feed roller 31 and the detection member 33, the thickness detection circuit 160 uses the data corresponding to the thickness of the reference original O as the reference value.
It is stored in the internal RAM 165 at the address designated by the control unit 61. This operation is similar to that of the thickness detection circuit 76 shown in FIG.

When it is detected that the reference document O is discharged, the main control section 51 guides the data registration on the display section 52a as shown in FIG.

Further, when the data of another original O is registered, the above operation may be repeated.

As a result, the data of the thickness corresponding to each size is stored on the RAM 165 backed up by the battery 166, as shown in FIG.

Now, after the registration of the data of the document O is completed, the normal mode is restored.

At this time, control unit 61 sets the start signal to "L" level. Then, the chip select signal of the delay circuit 161 becomes "H" level by the inverter 163.

On the other hand, since the chip select signal of the delay circuit 162 is at "L" level, the delay circuit 161 this time.
Is in a sleep state, and the delay circuit 162 is in an operable state.

Therefore, the detection data input to the automatic document feeder 20 in the normal mode is temporarily stored in the delay circuit 162 and compared by the comparator 167 with the data stored in the RAM 165 as a reference.

It goes without saying that the data stored in the RAM 165 retains the data at the time of data registration as it is because the delay circuit 161 is in the idle state in the normal mode.

In this way, it is possible to detect double feed or size.

The method of discriminating the output result of the comparator 167 is the same as the method based on the ROM data shown in FIG.

Automatic document feeder 2 for standard size only
When it is inserted into 0, since the length is not influenced by the type of the original O, the length detection circuit 75 shown in FIG. 60 may be used.

In this way, it is possible to perform double feeding or size detection by combining the detection result in the width direction and the detection result in the length direction.

An example of inputting an irregular size will be described below.

In this case, it is necessary to input the reference data also to the length detection circuit. The thickness is determined as described above using the block diagrams of FIGS. 71 and 72 and the address map of FIG. 76.

FIG. 77 shows a schematic block diagram of an embodiment of the length detection circuit 170 in this case. This length detection circuit 17
0 is a binarization circuit 171, a delay pulse generation circuit 172,
It is composed of an inverter 173, a counter 174, an address generation counter 175, a RAM 176, a battery 177, a latch circuit 178, and a comparator 169.

First, by the input of the input mode switching key 52d, the control section 61 of the automatic document feeder 20 switches to the data input mode. Then, the main control unit 51 displays a document size input screen as shown in FIG. 73 on the display unit 52a.

If the data of the original O of the standard size is registered as the reference data, each standard size is selected. In the case of the special irregular size, the irregular size 1 to
Select 4.

By this selection, the control unit 61 causes the display unit 5 to
The counter 175 generates an address corresponding to the size information designated by 2a.

Next, the original document O serving as a reference is fed by the paper feeding operation.
Before detecting the start signal, the control unit 61 sets the start signal to "H".
Level. At this time, the write enable signal (WE0) of the RAM 176 becomes "H" level.

On the other hand, since the chip select signal of the latch circuit 178 is at "H" level, the RAM 176 is in the writable state and the latch circuit 178 is in the idle state.

Here, when the automatic document feeder 20 is in the ready state, the main control section 51 displays the display section 52a, as shown in FIG.
As shown in, a reference document O insertion guide screen is displayed.

When the original O is detected by the empty sensor 29, the control section 61 starts the feeding operation, and the original O serving as the reference is fed in the feeding direction through the pair of registration rollers 34 and 35. Is fed to the lower surface side of the document transport belt 37 that is running.

When the reference original O passes between the paper feed roller 31 and the detection member 33, the length detection circuit 170 uses the data corresponding to the length of the reference original O as the reference value.
It is stored at the address designated by the control unit 61 in the internal RAM 176. This operation is similar to that of the length detection circuit 75 shown in FIG.

When it is detected that the reference document O is ejected, the main control section 51 guides the data registration on the display section 52a as shown in FIG.

Further, when the data of another original O is registered, the above operation may be repeated.

As a result, as shown in FIG. 77, the data of the length of each size is stored in the RAM 176 backed up by the battery.

[0409] Now, after the registration of the data of the original O is completed, the normal mode is restored.

At this time, the control section 61 sets the start signal to the "L" level. Then, the write enable signal (WE0) of the RAM 176 becomes "L" level.

On the other hand, since the chip select signal of the latch circuit 178 is at "L" level, this time the RAM 176 is selected.
Is in the write stop state, and the latch circuit 178 is in an operable state.

Therefore, the length data input to the automatic document feeder 20 in the normal mode is the latch circuit 17
8 and latched by the RAM 8 and stored in the RAM 176 as a reference and compared by the comparator 179.

It goes without saying that the data stored in the RAM 176 retains the data at the time of data registration as it is in the normal mode.

In this way, it is possible to detect double feed or size. The method of discriminating the output result of the comparator 179 is the same as the method based on the ROM data shown in FIG.

Needless to say, the switching between the mode and the normal mode at the time of registering the data of the reference original O is performed in association with each of the length and width (thickness) detection circuits.

By the way, normally, as described with reference to FIG. 76 and FIG. 78, double feeding is detected from the reference data stored in the non-volatile storage means, and an original of an irregular size or a type not normally used is detected. Only when the O is inserted, the double feed may be detected based on the data of the original O inserted as the first sheet.

With this structure, it is not necessary to register the data of the reference original document.

An embodiment in this case is shown in FIG. 79 by the length detecting circuit 180, FIG. 71 by the thickness detecting circuit 160, and FIG.
0, the data storage example shown in FIG. 81, the display examples shown in FIGS. 82 to 85, the flowcharts shown in FIGS. 86 to 90, and (a) to (c) of FIGS. 91 and 92 (a) to (d). This will be described with reference to the timing chart of the output waveform of the main part shown in FIG.

FIG. 79 shows a schematic block diagram of the length detection circuit 180 of this embodiment. This length detection circuit 180
The FF circuit 181 and the select circuit 182 are added to the length detection circuit 170 shown in FIG.

In the mode using the first original O as a reference,
The FF circuit 181 and the delay pulse generation circuit 172 are shown in FIG.
It is the same as the FF circuit 105 and the delay pulse generating circuit 105 shown in FIG. The chip select signal of the FF circuit 181 is at “H” level for the first original O and for the second and subsequent originals O is “L” level. The RAM 176 becomes writable for the original O, and the latch circuit 179 becomes operable for the second and subsequent originals O.

The select circuit 182 switches the output signal in accordance with the input mode switching signal supplied from the control section 61 in response to an instruction from the operation panel 52,
The chip select signal from the FF circuit 181 or the start signal from the controller 61 is selectively switched and output. The output from the select circuit 182 is
It is output as the write enable signal (WE0) of the RAM 176 and also output as the chip select signal of the latch circuit 178. That is, in the case of performing the double feed detection for the original O of the size stored in the RAM 176, the start signal is output from the control unit 61 to perform the double feed detection for the original O of the irregular size or the type not normally used. In this case, the FF circuit 181 outputs the chip select signal.

Further, as shown in FIG. 78, the RAM 176 stores each data of a fixed size and an irregular size, and a working for storing the data of the first sheet when the first sheet is used as a reference. An area as a RAM is prepared.

The thickness detection circuit 160 of this embodiment is also
The one shown in FIG. 69 is used. However, in this case, the signal input to the delay circuit 162 and the inverter 163 becomes the output of the select circuit 182 in FIG. 79. Also,
The RAM 165 has a standard size, as shown in FIG.
Stores each data of irregular size and 1
An area is prepared as a working RAM for storing the data of the first sheet when the first sheet is used as a reference.

First, the user inputs the input mode switching key 52d when inputting the original data. Then, the main control unit 51 switches to the data input mode and the display unit 5
At 2a, an input document selection screen as shown in FIG. 82 is displayed. On this screen, there are also three inquiries about whether to enter the original data, use a document other than the registered one, or return to the normal mode.

When the user selects the input of the document data in accordance with this guidance, the main control section 61 displays the document size input screen on the display section 52a as shown in FIG.

If the data of the original O of a standard size is registered as the reference data, each standard size is selected, and in the case of a special custom size, the custom sizes 1 to 1 are selected.
Select 4.

With this selection, the control unit 61 causes the display unit 5 to
The counter 175 generates an address corresponding to the size information (indeterminate type) designated by 2a.

Next, the original document O serving as the reference is fed by the paper feeding operation.
Before detecting, the control unit 61 outputs a switching signal so that the output of the select circuit 182 becomes the output from the control unit 61. Then, an “H” level start signal is output via the select circuit 182. At this time, RAM17
The write enable signal (WE0) of 6 becomes "H" level.

On the other hand, since the chip select signal of the latch circuit 178 is at "H" level, the RAM 176 is in the writable state and the latch circuit 178 is in the idle state.

Further, the control section 61 sets an address corresponding to the size information instructed by the display section 52a to the counter 16
Generate from 4.

The output of the select circuit 182 is the delay circuit 1
Since it is supplied to the inverter 62 and the inverter 163, the controller 61 sets the start signal to the “H” level. At this time, the chip select signal of the delay circuit 161 becomes "L" level by the inverter 163. On the other hand, the delay circuit 1
Since the chip select signal of 62 is at "H" level, the delay circuit 161 is in an operable state and the delay circuit 162 is in a dormant state.

Here, when the automatic document feeder 20 is in the ready state, the control unit 61 causes the display unit 52a to display the reference document O insertion guide screen as shown in FIG. When the empty sensor 29 detects the original O, the controller 61 starts the feeding operation, and the original O serving as the reference is running in the feeding direction via the registration roller pair including the aligning rollers 34 and 35. Is fed to the lower surface side of the document transport belt 37.

When the reference original O passes between the paper feed roller 31 and the detection member 33, the length detection circuit 180 uses the data corresponding to the length of the reference original O as the reference value.
It is stored at the address designated by the control unit 61 in the internal RAM 176. This operation is similar to that of the length detection circuit 170 shown in FIG.

The data corresponding to the thickness of the reference original O is used as the reference value in the RAM 16 in the thickness detection circuit 160.
5 is stored at the address designated by the control unit 61. This operation is similar to that of the thickness detection circuit 76 shown in FIG.

When it is detected that the reference document O is discharged, the main control section 51 guides the data registration on the display section 52a as shown in FIG.

Further, when the data of another original O is registered, the above operation may be repeated.

As a result, as shown in FIG. 80, the RAM 176 backed up by the battery 177 stores the data of the length of each size, and the RAM 165 backed up by the battery 166 is shown in FIG. As shown, the data of the length of each size is stored.

Then, in the state where the display unit 52a is instructed to finish the registration of the data in FIG. 85, when NO is selected in response to the guidance of another data input, the control unit 61 , Return to normal mode.

At this time, the control section 61 sets the start signal to the "L" level. Also at this time, the output of the select circuit 182 is the same as the signal from the control unit 61. This start signal is sent to the RAM 176 via the select circuit 182.
And is output to the latch circuit 178. This gives R
The write enable signal (WE0) of AM176 is
It goes to "L" level, and the chip select signal of the latch circuit 178 goes to "L" level. As a result, this time RA
M176 is in the write stop state, and the latch circuit 17
8 is in an operable state.

Therefore, the length data input to the automatic document feeder 20 in the normal mode is the latch circuit 17
8 and latched by the RAM 8 and stored in the RAM 176 as a reference and compared by the comparator 179.

It goes without saying that the data stored in the RAM 176 retains the data at the time of data registration as it is in the normal mode.

The method of discriminating the output result of the comparator 179 is the same as the method based on the ROM data shown in FIG.

Further, in the thickness detection circuit 160 of FIG. 71, when returning to the normal mode, the control section 61 sets the start signal to the "L" level. Then, select circuit 1
Since the output of 82 and the signal (start) of the control unit 61 are the same, the chip select signal of the delay circuit 161 becomes "H" level by the inverter 163.

On the other hand, since the chip select signal of the delay circuit 162 is at "L" level, this time the delay circuit 161
Is in a sleep state, and the delay circuit 162 is in an operable state.

Therefore, the thickness detection data input to the automatic document feeder 20 in the normal mode is the delay circuit 1
The data temporarily stored in 62 and stored in the RAM 165 are compared by the comparator 167.

It goes without saying that the data stored in the RAM 165 holds the data at the time of data registration as it is because the delay circuit 161 is in the idle state in the normal mode.

The method of discriminating the output result of the comparator 167 is the same as the method based on the ROM data shown in FIG.

In this way, double feeding or size detection can be performed by combining the detection result in the width (thickness) direction and the detection result in the length direction.

Next, in the input document selection screen of FIG. 82, when it is selected that a document other than the registered document is used, the control section 61 shifts to the mode for detecting the double feed with the data of the first sheet as a reference.

As a result, the control section 61 switches the select circuit 182 to the FF circuit 181 side (A side). As a result, the length detection circuit 180 becomes the length detection circuit 75 of FIG.
As described above, the double feed is detected based on the data of the first sheet. At this time, the area of the RAM 176 as a working RAM is selected by the address of the counter 174, and the first reference data is stored in this area.

Further, in this mode, the output of the comparator 179 of the length detection circuit 180 is set to 16 bits, and the comparison results CPR1 to 8 are the original data fed in the fixed form data stored in the RAM 176. When the size exists, the comparison result output of the corresponding size is set to the “L” level, and the comparison results of the lengths of the first and second sheets are compared results CPR 9 to 1.
It may be configured to output from 1. In this case, the size can be detected even when an original different from the one in the normal mode is inserted.

Further, the thickness detection circuit 160 detects double feed with reference to the data of the first sheet, as described using the thickness detection circuit 76 of FIG. At this time, the area of the RAM 165 as the working RAM is selected by the address of the counter 164, and the first reference data is stored in the area.

Further, in the thickness detection circuit 160, when a cut and pasted original is inserted, it is not erroneously detected as a double feed,
As in the case of FIG. 53, the minimum value detection circuit is replaced with the delay circuit 16
It may be added after 1, 162. Heretofore, the method of discriminating the size and the double feed has been described.

Next, a description will be given of an embodiment in which the skew of the fed document O is detected by using different voltage values output according to the resistance value change of the pressure-sensitive conductive rubber 33b in the detection member 33. To do.

FIG. 93 shows the case where various originals O are sandwiched by the rotary feeder 35 using the pressure-sensitive conductive rubber 33b.
It shows the change over time in the output of the detection circuit 73.

Here, the thicker the original O, the larger the value on the vertical axis.

FIG. 93A shows the output when the skewed original O is inserted.

That is, in the case of the skewed original O, the width of the original O sandwiched by the rotary feeding member 35 becomes longer with the passage of time. Therefore, the output of the detection circuit 73 also increases with the passage of time.

On the other hand, FIG. 93 (b) shows the output of the detection circuit 73 when the paper is fed normally. In this case, the output of the detection circuit 73 becomes constant after the front end of the document O is pinched.

FIG. 93C shows the output result of the detection circuit 73 when the cut and pasted original O is inserted. In this case, after the front end of the original O is pinched, the portion of the reference original O has a constant value, and the output at the edge of the cut and pasted portion is
Although it changes, it becomes a constant value again at the cut and paste part.

As described above, the skew can be detected by detecting the temporal change in the output of the original O from the time when the original O is sandwiched by the rotary feeding member 35.

FIG. 94 is a schematic block diagram of the skew detection circuit 190. The skew detection circuit 190 includes latch circuits 191, 192, 193, a decoder 194, and comparators 195, 196. The skew detection circuit 190 is provided between the A / D converter 74 and the control unit 61 shown in FIG. 3, and supplies the binarization signal from the binarization circuit 198 that binarizes the output of the detection circuit 73. It is supposed to be done. The binarization circuit 198 is the same as that used in the length detection circuit 75 and the thickness detection circuit 76. When the length detecting circuit 75 and the thickness detecting circuit 76 are provided, the binarized signals of the binarizing circuits 101 and 111 may be used.

When the original O is sandwiched between the detection member 33 and the paper feed roller 31, the pressure-sensitive conductive rubber 33 whose pressure has changed.
The change in resistance value from b is converted into an electric signal by the detection circuit 73 and binarized by the binarization circuit 198.

The output of the binarization circuit 198 outputs "L" level while the original O is present on the detection member 33 and the paper feed roller 31, as shown in FIG. Becomes "H" level.

The output of the binarization circuit 198 is the latch circuit 1
91, 192 and 193 are supplied to the chip select terminals (CS), and the latch circuits 191 and 19 are provided.
Reference numerals 2 and 193 operate only while the document O is present between the detection member 33 and the paper feed roller 31.

On the other hand, the decoder 194 receives a master clock from an oscillator (not shown) or a clock obtained by dividing the master clock as a sampling pulse. Further, the decoder 194 includes a binarization circuit 1
The output of 98 is also supplied.

At the time of the fall of the binarized output, the decoder 194 has three types of pulses a, b, which have different output timings as shown in (b), (c) and (d) of FIG.
c is output to the latch circuits 191, 192, and 193, respectively.

The latch circuits 191, 192 and 193 detect the detection circuit 7 at the time when the pulses a, b and c are input, respectively.
3 output data (DATA1 to 3) is latched.

The data output to the latch circuits 191, 192 and 193 are compared by comparators 195 and 196.

In the comparator 195, DATA1 and DATA
2 is compared, and if DATA1 ≠ DATA2, the “H” level is output to the AND circuit 197.

The comparator 2 compares DATA2 and DATA3, and if DATA2 ≠ DATA3, outputs an “H” level to the AND circuit 197.

The AND circuit 197 outputs the "H" level to the control section 61 when the outputs of the comparators 1 and 2 are both at the "H" level.

That is, DATA1 ≠ DATA2 and D
If ATA2 ≠ DATA3, the level becomes “H”.

In the control section 61, the AND circuit 197 is "H".
If it is at the level, it is determined that the sheet is skewed and the sheet feeding operation is stopped.

If there is no skew as shown in FIG. 93 (b), DATA1 = DATA2 and DATA2 = DATA3, so the output of the AND circuit 197 becomes "L" level.

Similarly, in the case of FIG. 93 (c), DAT
Since A1 = DATA2, the output of the comparator 195 is
It becomes the "L" level. Since DATA2 ≠ DATA3, the output of the comparator 196 becomes “H” level.

Then, the output of the AND circuit 197 is
It becomes the "L" level.

As described above, the skew can be effectively detected.

The number of times of sampling for the length of the original O can be adjusted by setting the cycle of the sampling clock of the decoder 194.

Further, in the case of the cut and pasted original O, if the cut and pasted portion is not in the direction perpendicular to the feeding direction, there is a possibility of erroneous detection.

As in the present embodiment, the output of the detection circuit 73 is binarized, the leading edge of the document O is detected, and then the sampling is performed to detect the skew of the reference document O and avoid the possibility of erroneous detection. be able to.

Further, when the skew of the document O occurs, the skew can be detected early.

Therefore, it is possible to prevent the skewed original document O from being conveyed as it is, being broken, or being caught in the side frame of the automatic document feeder 20 to be damaged. it can.

The automatic document feeder 20 is provided so as to be openable and closable with respect to the document table 2 of the copying machine main body 1. Therefore, when the automatic document feeder 20 is opened, the detection member 3
By releasing the pressure applied to the sheet feeding roller 31 and the sheet feeding roller 31 during normal use, the output of the detection circuit 73 according to the resistance value change of the pressure sensitive conductive rubber 33b in the detection member 33 is
The output is smaller than the output when the original O is not bited in the normal use.

By detecting this output difference, it is possible to detect that the automatic document feeder 20 is in the open state, and stop the paper feeding operation, thereby preventing malfunction.

Conventionally, a dedicated switch for detecting the open state was required, but with the above configuration, the dedicated switch can be omitted and an inexpensive automatic document feeder 20 can be constructed. it can.

This embodiment will be described below.

The detection circuit 73 (A / D converter 74) for the three states (conditions) shown in (a) to (c) of FIG. 96 and FIG. 104 for the detection member 33 and the paper feed roller 31.
To output signals as shown in FIG.

FIG. 96A shows a state in which the original O is not pinched during normal use, and the detection circuit 73 outputs a signal at the level (a) shown in FIG. 97.

FIG. 96 (b) shows a state in which the original O is pinched, and the detection circuit 73 outputs a signal at the (b) level shown in FIG. 97.

96 (c) and 104 show the automatic document feeder 20 in the open state, and the detection circuit 73
Outputs a signal of level (c) shown in FIG.

In the case of FIG. 97, the higher the pressure is, the more the output of the detection circuit 73 under each condition when the output is upward.

First, one example will be described.

Before the automatic document feeder 20 is used,
The operation panel 5 of the main body device or the automatic document feeder 20 at the time of unpacking the setting or at the time of factory shipment
Switch from 2 to service mode.

When entering this service mode, FIG.
The input switching key 52d and the clear key 52e of No. 3 are simultaneously pressed. Then, this signal causes the main control unit 51 and the control unit 61 to enter the service mode.

The method of setting this service mode may be another method.

For example, it may be performed by switching the dip switch.

[0498] When the service mode is entered, a menu as shown in Fig. 98 is displayed.

If MENU1 is selected here, FIG.
Appears, and when [YES] is selected, the control unit 61 that has detected this signal performs the following operation.

In FIG. 71, the control unit 61 operates the address generation counter 164 to select an address (F000 to FFFF) on the RAM 165 for a state where the document is not sandwiched during normal use.

The address of the RAM 165 at this time is shown in FIG.
00.

The control unit 61 prohibits writing in this area except in the service mode.

The control section 61 sets the start signal to the "H" level. At this time, the chip select signal of the delay circuit 161 becomes "L" level by the inverter 163,
The chip select signal of the delay circuit 162 becomes "H" level. As a result, the delay circuit 161 is in the operable state and the delay circuit 162 is in the idle state.

Therefore, the output of the detection circuit 73 is temporarily stored in the delay circuit 161, and the data is stored in the above-mentioned address on the RAM 165.

Then, the main control unit 51 displays the registration completion guide screen of the standard state data on the display unit 52a as shown in FIG.

Now, when returning to the normal mode, the controller 61
Sets the start signal to the "L" level. At this time,
The delay circuit 161 is suspended, and the delay circuit 162 is in an operable state.

When the automatic document feeder 20 is in the open state, the output of the detection circuit 73 is temporarily stored in the delay circuit 162, and the data in the state where the original O in the normal use on the RAM 165 is not sandwiched and the comparator 162. Be compared. At this time, in the comparator 162, the data in the state where the document O in the normal use on the RAM 165 is not sandwiched is the delay circuit 1
If it is larger than the detection data of 62, the comparison result CPR1
Is set to the “L” level.

When the control section 61 reads this, it outputs to the main control section 51 that the automatic document feeder 20 is open, and the comparison result CPR1 of the comparator 167 is "L" level. Prohibits the start of paper operation. Further, the main control section 51 displays on the display section 52a that the automatic document feeder 20 is open.

By the way, reference data of various sizes are stored in the RAM 165, and the same comparison result CPR1 is used for size detection.

However, the opening / closing of the automatic document feeder 20 is detected only at the time of initialization immediately after the power is turned on, or when the paper feeding operation after detecting a jam, double feeding or skew is stopped. If so, no problem occurs.

Further, the output of the comparator 167 is set to 8 bits or 16 bits, and the RAM 16 shown in FIG.
The open / closed detection result of the paper feed mechanism other than the comparison result with other reference data stored in 5 (that is, the size determination result and the double feed determination result) may be assigned.

[0512] In this case, the control unit 6
In No. 1, the determination result can be read based on the state in which the paper feed operation is possible when the original O does not exist.

An example is shown in Table 12 below.

[0514]

[Table 12] A flow chart for explaining the processing of the above embodiment is shown in FIG.

[0515] Further, the automatic document feeder 2 is equipped with a dedicated circuit.
The open / closed state of 0 may be detected.

An embodiment in this case is shown in FIG.

In this case, the data corresponding to the output of the detection circuit 73 in a state where the original is not pinched during normal use is set by the switch 201 at the time of unpacking the setting or at the time of factory shipment. The output of the detection circuit 73 is A /
The digital data is converted by the D converter 74 into the comparator 20.
2 is always input. The CS terminal of the comparator 202 is connected to the output of the AND circuit 203. The AND circuit 203 has an interrupt signal from the control unit 61 and an I signal.
/ O read signal is supplied.

That is, the output of the comparator 202 is sent to the control unit 61 only when the interrupt signal from the control unit 61 and the I / O read signal occur simultaneously.

With this structure, the control section 61 can detect the open / closed state of the automatic document feeder 20 at any time when other processing is not performed.

Next, when the double feeding of the fed original O is detected by using the different voltage values output according to the resistance value change of the pressure-sensitive conductive rubber 33b in the detection member 33, the accumulation is performed. An embodiment will be described in which the average value of the read data is calculated and the average value data is compared with the detection value of the fed document O.

The first example is for the case where the type of the original O is one.

[0522] First, the user automatically inserts a plurality of originals used in the automatic original feeder 20 into the automatic original feeder 2.
A description will be given of an embodiment of a multi-feed detection circuit that inserts the data into 0, calculates the average value of the data of the original, and then detects the multi-feed based on the average value.

FIG. 105 is a schematic block diagram of a thickness detecting circuit 210 as a double feed detecting circuit showing this embodiment.

This thickness detection circuit 210 is a binarization circuit 2
21, various timing generation circuits 211, delay circuits 21
2, 213, 218, inverter 214, adder 21
5, a latch circuit 216, a data select circuit 217, a comparator 219, and a battery 220.

The binarizing circuit 221 is the same as the one used in the length detecting circuit 75 and the thickness detecting circuit 76, and as shown in FIG. And a circuit for outputting an "L" level binarization signal when it is sandwiched between the paper feed rollers 31.

As shown in (a) of FIG. 106, when the binary signal from the binarizing circuit 221 becomes the "L" level, the various timing generation circuits 211 are set to (b) of FIG. As shown in FIG. 106, a leading edge detection pulse is generated, a rising signal of the leading edge detection pulse is detected, and then a latch clock obtained by dividing a master clock from an oscillator (not shown) is generated as shown in (c) of FIG. After detecting the first rising output of the latch clock, (d) in FIG.
As shown in, the input / output control signal held at "H" level is set to "L" level.

[0527] The latch clock is designed to generate a specific number after the leading edge of the document is detected.
If is not sandwiched between the detection member 33 and the paper feed roller 31, it does not occur. The input / output control signal can be formed, for example, by inputting a latch clock to the FF circuit.

The number of times of sampling one original O or the total number of samplings can be set by the user or a serviceman via the control unit 61.

[0529] The latch clock and the input / output control signal from the various timing generation circuits 211 are output to the latch circuit 216.

Further, the various timing generation circuits 211 are
As the calculation of the average value, how many upper bits of the data select circuit 217 are output to the delay circuit 218 is output to the data select circuit 217 as a data select signal.

Before the reference document O is detected by the paper feeding operation, the control section 61 sets the mode switching signal to the "H" level. At this time, the chip select signal to the delay circuit 212 becomes "L" level by the inverter 214, and the chip select signal to the delay circuit 213 becomes "H".
It becomes a level. As a result, the delay circuit 212 is in the operable state and the delay circuit 213 is in the idle state.

When the automatic document feeder 20 is now in the ready state, the main control section 51 displays the display section 52a, as shown in FIG.
As shown in, a reference document O insertion guide screen is displayed.

When the original O is detected by the empty sensor 29, the controller 61 starts the feeding operation, and the original O serving as the reference is fed in the feeding direction via the registration roller pair composed of the aligning rollers 34, 34. Is fed to the lower surface side of the document transport belt 37 that is running.

When the reference document O passes between the paper feed roller 31 and the detection member 33, the detection circuit 73 detects the resistance value change of the detection member 33 corresponding to the thickness of the reference document O. The 8-bit data obtained by the A / D converter 74 is supplied to the delay circuit 212. This data is delayed by the delay circuit 212 and then output to the adder 215. In the adder 215, the delay circuit 2
The data from 12 and the latch content of the latch circuit 216 are added, and the latch content of the latch circuit 216 is updated by the addition result.

Further, the data detected by the detection circuit 73 due to the change of the resistance value of the detection member 33 is converted into the binarization circuit 221.
Is supplied to. Then, the binarization circuit 221 outputs an "L" level binarized signal. Based on this output signal, the various timing generation circuits 211 generate a leading edge detection pulse and output it to the latch circuit 216.

Then, after detecting the first rising output of the latch clock, the various timing generation circuits 211 receive the output control terminals (O) of the latch circuit 216.
The input / output control signal to C) is changed from "H" level to "L" level.

The average value of data is calculated as follows.

The data temporarily stored in delay circuit 212 is sent to adder 215.

FIG. 108 is a timing chart showing the data input / output timing of the latch circuit 216.

There is a delay time from when the original O is pinched to when the latch clock rises. Until the first latch clock is input to the latch circuit 216,
Since the output control terminal (OC) is at "H" level, the latch circuit 216 is in a high impedance state, and its output is in the state of being dropped to the ground through the resistance value, that is, "0" level. "0"
The data from the level and delay circuit 212 is added to the adder 215.
Is added by

Here, the data from the A / D converter 74 is 8 bits, and the output of the latch circuit 216 is 16 bits. The addition result is the latch circuit 216 as 16-bit data obtained by adding the lower 8-bit data of the output of the latch circuit 216 and the data from the A / D converter 74.
Is output to.

The data after this addition is defined as (1). This data (1) is latched in the latch circuit 216 when the first latch clock arrives. Further, the data (1) is input to the adder 215 as the output of the latch circuit 216 this time, and is added by the adder 215 to the second detected data stored in the delay circuit 212. This data is referred to as data (2). Data (2) is latched when the next latch clock arrives. This time, the data (2) is added to the data of the third time as the output of the latch circuit 216.

Thereafter, by repeating this operation, the sampled addition result is stored in the latch circuit 216.

When the sampling of the predetermined number of times is completed, the various timing generation circuits 211 stop the latch clock.

In accordance with the number of samplings, each timing generation circuit 211 outputs to the data select circuit 217 a data select signal indicating how many upper bits are output to the delay circuit 218.

Thus, the data select circuit 217
Latch circuit 21 in response to the data select signal.
The higher-order bits of the data stored in 6 are output to the delay circuit 218 as average value data.

As described above, after the predetermined number of samplings are finished, the various timing generation circuits 211 output to the control unit 61 and the main control unit 51 that the sampling is finished.

Then, the main control section 51 issues a command to display on the display section 52a as shown in FIG. If the user or serviceman selects [YES] here, the normal detection mode is entered.

At this time, control unit 61 changes the mode switching signal from "H" level to "L" level.

Then, the delay circuit 212 is put in the idle state this time, and the delay circuit 213 is put in the operable state. Therefore, the output from the A / D converter 74 is the delay circuit 213.
Will be temporarily stored in.

On the other hand, this mode switching signal is applied to the delay circuit 2
It is also supplied to 18 chip select terminals (cs). As a result, the average value of the addition data accumulated in the latch circuit 216 is temporarily stored in the delay circuit 218. By comparing the data of the delay circuit 213 and the data of the delay circuit 218 with the comparator 219, it is possible to detect the double feed based on the averaged reference data.

The latch circuit 216 is connected to the battery 22.
0 is backed up by the automatic document feeder 2
Even if the power of 0 is turned off, the reference data is retained.

[0553] Further, the length detection circuit 75 is used to detect the double feed.
You may combine the data of. Similarly, the lengths may be averaged and the data may be used as a reference.

Here, it is also possible to sample the first original O a plurality of times, calculate the average value, and detect the double feeding of the second and subsequent originals O.

In this case, the mode switching signal is sent to the control unit 61.
FF in the length detection circuit 75 shown in FIG.
The chip select signal from the circuit 105 may be used.

As in the case of FIG. 34, a delay pulse generation circuit 112 for generating a delay pulse by the binarized output of the binarization circuit 221 and an FF circuit 113 for setting by this delay pulse are provided, and this chip select You may make it use a signal.

In this case, the chip select signal of the FF circuit 105 (113) is at "H" level until the first original O passes and a delay pulse is generated. Hereinafter, the same operation as that in the reference data averaging mode described above may be performed. For the second and subsequent sheets, the chip select signal of the FF circuit 105 is switched from the "H" level to the "L" level, so the same operation as in the normal mode described above may be performed.

In this case, various timing generation circuits 21
1 may be configured to stop the latch clock only at the first clock. Alternatively, the chip select signal of the FF circuit 105 may be input to the various timing generation circuits 211 to output the latch clock only for the first sheet.

Timing charts of respective signals in this case are shown in FIGS. 110 (a) to 110 (f).

As described above, only one type of data is latched by the latch circuit 2.
The embodiment in which the average value is calculated by storing in 16 has been described.

[0561] This may store several kinds of data. An example in which a memory is used as the ck storage means is shown in FIG.
Shown in.

FIG. 111 is a schematic block diagram of a thickness detecting circuit 230 as a double feed detecting circuit of this embodiment. The thickness detection circuit 230 includes a binarization circuit 230a, various timing generation circuits 231, delay circuits 232, 233, 23.
4, 235, adder 236, memory (eg RAM)
237, latch circuit 238, data select circuit 23
9, a comparator 240, and an inverter 240a.

In this case, the mode switching signal is sent to the control unit 61.
Signal from.

The method of mode switching is similar to the case of storing only one type of data in latch circuit 216 in the case of FIG.

As shown in FIG. 112, the various timing generation circuits 231 are provided with a frequency dividing circuit 241 and a delay circuit 24.
2, a counter 243, AND circuits 244 and 245, and an FF circuit 247, which divides the master clock (M-CLK) to write clock (WT).
-CLK), and the latch circuit 23 in the latter stage of the memory 237.
8 latch clocks (LT-CLK) are generated.

The WT control signal is connected to the clear terminal of the counter 243 and the preset terminal of the FF circuit 247. The WT control signal is used as a leading edge detection pulse because it produces an effective pulse at the "L" level at the leading edge of the document O.

At the moment when the WT control signal becomes "L" level, all the outputs of the counter 243 become "0", and FF
The chip select signal of the circuit 247 becomes "H" level. The counter 241 counts up with the write clock LT-CLK obtained by dividing the master clock M-CLK, and when it becomes a constant value, the AND circuit 244 outputs the “L” level. This output is the FF circuit 247.
Is input to the clear terminal of and the set output becomes "L" level.

The set output of the FF circuit 247 is
It is shown that the mode is used for the control for performing the predetermined sampling in the reference data input mode.

Next, a concrete example of storing the average value for each size in the address of the memory 237 will be shown.

(1) When only one type of data is stored Stored in 0000.

When one type of data is stored in the memory 237, the display section 52a becomes as shown in FIG.

(2) When storing data of several kinds of originals For example, the following addresses are determined according to size. Size detection can be performed at the same time by counting up one by one from the start address corresponding to each size according to the sampling number.

0000 ← A3 data storage address 1000 ← A4 data storage address 2000 ← A5 data storage address ······· 7000 ← irregular data 1 storage address 8000 ← irregular data 2 storage address Select this address area. This can be done by selecting the size on the display of the display unit 52a as shown in FIGS. 73 and 74 before inserting the reference document.

Further, after detecting the size by the size detection circuit described above, the control unit 61 may determine the address area according to the size.

In the reference data input mode, the data of A / D converter 74 is stored in delay circuit 232.

The timing of various signals at this time is shown in FIG.
3 (a) to (g).

When the first reference document sheet is sandwiched by the detection mechanism, the leading edge detection pulse is generated from the falling output of the binarization circuit 230a.

After detecting the rising signal of the leading edge detection pulse, the various signal generation circuits 231 start generating the write clock WT-CLK which is the write signal of the memory 237.

When the number of samplings reaches a predetermined number, a sampling stop signal is output and this write clock WT-
CLK stops.

Then, as described above, an address corresponding to the same position from the leading edge of the original O is formed, and the memory 23
Will be sent to 7.

The write clock is configured to stop before detecting the trailing edge of the document O.

The chip select signal of the FF circuit 105 of the length detection circuit 75 is input to the output control terminal (OC) of the latch circuit 238.

[0583] The length of the first original document O has passed and the length detection circuit 7 has been detected.
The chip select signal holds the “H” level until the delayed pulse from 5 is generated.

Therefore, the output control terminal (OC) of the latch circuit 238 is in the high impedance state, and the output of the latch circuit 238 is connected to the reference potential GND through the resistance value.
The level becomes "0".

In the adder 236, the lower 8 bits of the output of the latch circuit 238 which produces a 16-bit output and the delay circuit 23.
8 bits of 2 are added.

[0586] While the first data is being input, the latch circuit 2
Since the output of 38 is the "0" level, the detected data is actually output as it is.

The output of adder 236 is stored in delay circuit 234. The write clock WT-CLK is input to the output control terminal (OC) of the delay circuit 234.

FIGS. 113 (a) to 113 (g) are timing charts showing data input / output.

When the write clock WT-CLK is at "L" level, the output of the delay circuit 234 is output to the memory 237.

On the contrary, the write clock WT-CLK is "H".
When the level is set, the output of the delay circuit 234 is not output, and the output data from the memory 237 is valid.

On the other hand, the write clock WT-CLK is also input to the write terminal of the memory 237.

As described above, various timing generation circuits 2
From 31, an address is generated in the memory 237 at a timing delayed by one count with respect to the write clock WT-CLK.

Therefore, the write clock WT-CLK
The output of the delay circuit 234 at the rising edge of
It is stored in a designated address inside 37.

The above operation is repeated for a predetermined number of sampling times.

From the second sheet onward, the set output of the FF circuit becomes "L" level.

Here, the detection data of the second sheet and the detection data of the first sheet are added at the same timing from the leading edge of the original O. The addition result is stored in the memory 237 via the delay circuit 234 at the address of the same timing as the first sheet.

From the third sheet onward, the same operation as that of the second sheet is performed until the sampling is completed. After the addition of the data of the document O is completed, the normal mode is restored. At this time, the control unit 61 sets the mode switching signal to the “L” level. Then, the chip select signal of the delay circuit 232 is
The inverter 241 brings it to the “H” level, and the chip select signal of the delay circuit 232 goes to the “L” level.
As a result, the delay circuit 232 is in a rest state this time, and the delay circuit 233 is in an operable state.
The latch clock LT-CLK and the address control signal are generated at the same timing as the reference data input mode even in the normal mode.

The addition result of the reference data output from the address of the memory 237 at the above clock is the latch circuit 23.
After being stabilized at 8, the data select circuit 239 outputs an arbitrary 8-bit data corresponding to the total number of samplings to perform the averaging process.

Therefore, the data of the document O to be detected can be compared with the average value of the reference data sampled at the same timing as the reference data.

In the normal mode, the data stored in the memory 237 holds the data at the time of data registration as it is because the delay circuit 232 is in a rest state and the write signal WT-CLK is stopped. is doing.

In this way, double feeding can be detected.

This detection result may be combined with the result of the length detection circuit 75.

Also, the method of detecting the conveyance state of the original O using the output from the detection circuit of one system has been described so far, but the conveyance state of the original O is detected based on the outputs of the plurality of detection circuits. It is also possible to detect.

Next, another example of the thickness detecting circuit having the same structure as that of FIG. 111 is shown below. The internal structure of each timing generation circuit 231 is shown in FIG. The difference between this configuration and FIG. 112 described above is that an AND circuit 246 is added and accordingly a counter 248 for managing the address of the memory 248 is provided. In FIG. 112, the address signal from the control unit 61 is directly input to the memory 247, but this time, the address signal from the control unit 61 is input to the counter 248. This allows
The memory 247 can be counted up according to the write clock (WT-CLK).

With this method, it is possible to detect double feeding based on the result of weighted averaging of the thickness data for each part of the original O using a plurality of reference originals O. The timing chart is shown in FIG.
5 (a) to (g), and an operation explanatory diagram is shown in FIG.

The specific operation will be described below. First original O
115 is completed, the set output (chip select signal) of the FF circuit 105 of the length detection circuit 75 is kept at "H" level as shown in FIG. 115 (b). Since this signal is in the "H" level state, the output of the latch circuit 238 shown in FIG. 111 is in the high impedance state, and the output of the latch circuit 238 is "00" due to the connected GND ground resistance. "It becomes. Therefore, the thickness data of the first original O is stored in the memory 237 as it is. The above operation is the same as the method of detecting the thickness by sampling one document O a plurality of times.

Next, in the case of the second reference original O, the set output (chip select signal) of the FF circuit 105 of the length detection circuit 75 becomes the "L" level, and the latch circuit 238 stores it in the memory 237. The first standard document O
The thickness data of is output. The thickness data of the first reference document O and the thickness data of the second reference document O are added by the adder 23.
6 is added, and the addition result is stored in the memory 237 via the delay circuit 234.

As for the thickness data, as shown in FIG. 116, the sampling results of the same location from the leading edge of the original O are always added. This operation is performed up to the nth reference document O. As a result, the memory 237 stores the addition result for each location of the original O added n times. Double feeding detection is performed by comparing the thicknesses of the original O conveyed with 1 to n of these addition results as reference data.

Addition timings of the write clock (WT-CLK), the latch clock (LT-CLK) and the memory 237 are shown in FIGS. 113 (a) to 113 (g).

Although the above description has been made for one type of original O, in the case of plural types of original O, the memory 23
Address 7 should be set.

(1) To store only one type of original data 0000 to (2) To store multiple types of original data 0000-0FFF ... A3 data storage area 1000-1FFF ... A4 data storage area 2000-2FFF … A5 data storage area ・ ・ ・ ・ ・ ・ ・ ・ ・ 7000-7FFF… Amorphous data 1 storage area 8000-8FFF… Amorphous data 2 storage area FIGS. 117 to 121 show two detection members 33a and 33b.
In this embodiment, the document is divided and arranged in a direction orthogonal to the feeding direction of the document O.

In FIG. 117, detecting members 33a, 33
b are arranged in contact with the paper feed roller 31 in contact with each other. These detection members 33a, 33b
Are composed of a conductive layer 321, a pressure-sensitive conductive rubber 322, a support member 323, and harnesses 324 and 325, respectively. As a result, the harnesses 324 and 325 allow the detection members 33a and 33b and the input end 7 of the detection circuit 73 to be detected.
3a and 73b are connected. The detection member 33
a and 33b have the same configuration as that of FIG.

FIG. 118 shows an example in which the detection members 33a and 33b are supported by the same support member. In this case, as shown in FIG. 119 (a), the conductive layer 321 and the pressure-sensitive conductive rubber 322 are provided separately, or
As shown in (b) and (c) of FIG.
In 22, the conductive layer 321 is divided into two. 12
0 (a) (b) (c), FIG. 121 (a) (b) (c)
117 are the detection members 33a and 33b shown in FIGS.
The feeding state of the document O with respect to and the output from the detection circuit 73 at that time are shown. In the case of FIG. 120, the original O is fed normally, and in the case of FIG. 121, the original O is fed.
Shows that the paper is being skewed and being fed.

An embodiment in which the skew of the original O is detected based on the signals from the two detection members 33a and 33b shown in FIGS. 117 to 121 will be described.

That is, in detecting the skew,
The controller 61 can detect the skew by comparing the outputs from the detection circuits 73a and 73b, that is, the outputs from the binarization circuits 79a and 79b.

FIG. 122 is a schematic block diagram of this skew detection circuit.

When the original O is sandwiched between the detection members 33a and 33b and the paper feed roller 31, the outputs of the binarization circuits 79a and 79b change from "H" level to "L" level. At this time, the output of the exclusive OR of the outputs of both the binarization circuits 79a and 79b by the EXOR gate 80 is as shown in Table 13 below.

[0618]

[Table 13] When the document O is skewed, it is in the state of 2 or 3, so the control unit 61 may detect the skew when the output of the EXOR gate 80 becomes the “L” level. At this time, the control unit 61 stops the paper feeding operation.

123 and 124 show the six detection members 3.
In the embodiment, 3a, ... Are divided and arranged in a direction orthogonal to the feeding direction of the document O.

That is, the detection members 33a, ... Are arranged so as to be in contact with the paper feed roller 31 while being in contact therewith. The detection members 33a, ... Include protective layers 320a, .., conductive layers 321a ,.
2a, ..., Support member 323a, .., Harness 324a,
.., 325a ,. As a result, the harnesses 324a, ..., 325a, .. .. and the input ends 73a, 7 of the detection circuit 73 and the detection members 33a ,.
3b is connected. The detection members 33a, ...
It has the same configuration as that of FIG.

In this case, A5 shown in FIG.
When an original O of horizontal / A4 vertical is fed, as shown in FIG. 125 (b), the two detection members 33c at the central portion,
Corresponding to the change in the resistance value of the pressure-sensitive conductive rubbers 322c and 322d corresponding to 33d, the detection circuit 73 outputs Pa when the thickness of the first original O or Qa when the original O is double-fed. Further, when the B5 horizontal / B4 vertical document O shown in (a) of FIG. 125 is fed, as shown in (c) of FIG. 125, the two detection members 33b and 33e second from the end are fed. When the thickness of the first original O from the detection circuit 73 corresponds to the change in resistance value of the corresponding pressure-sensitive conductive rubbers 322b and 322e, P
b or Qb is output in case of double feed.

[0626] Also, as shown in FIG.
When the A3 portrait original O is fed, as shown in FIG. 125 (d), the resistance values of the pressure-sensitive conductive rubbers 322a and 322f corresponding to the two detection members 33a and 33f at the ends are changed. When the thickness of the first original O from the detection circuit 73 is Pc
Alternatively, Qc is output in the case of double feed.

As shown in FIG. 124, the pressure-sensitive conductive rubber 32
It is advantageous in that the thickness can be secured to some extent in terms of the change in resistance value of 2a, ..., That is, the sensitivity. This is because the change rate of the resistance value is different for the same pressure as the thickness is different.

By the way, the detection member 3 which is divided respectively
If the widths of 3a, ... Are made equal to each other, the values of the outputs from the respective conductive layers when the original O is sandwiched are the same. This facilitates size detection and skew detection, which will be described later.

Next, an embodiment of the size detecting circuit for detecting the size of the original O passing between the detecting member 33 and the feeding roller 31 will be described with reference to FIGS.

This size detection circuit is shown in FIG.
As shown in FIG. 6, three detection circuits 73a, 73b, 73
c, a binarization circuit 79a, 79b, 79c, and the control unit 61. Each of the detection circuits 73a, ... Has the configuration shown in FIG.

A signal from the pressure sensitive conductive rubbers 322c and 322d is applied to the conductive layer 321 at one input end of the detection circuit 73a.
c, 321d and the harnesses 324c, 324d, and the signal from the pressure-sensitive conductive rubber 322b, 322e is applied to one input end of the detection circuit 73b by the conductive layer 321b,
321e and harnesses 324b and 324e, and signals from the pressure-sensitive conductive rubbers 322a and 322f are applied to one input end of the detection circuit 73c.
1f is guided through harnesses 324a and 324f. Signals from the pressure-sensitive conductive rubbers 322c and 322d are input to the other input ends of the detection circuit 73a.
25d, the signal from the pressure-sensitive conductive rubber 322b, 322e is guided to the other input end of the detection circuit 73b via the harnesses 325b, 325e, and the other input end of the detection circuit 73c is connected to the other input end. , Pressure-sensitive conductive rubber 322a, 3
A signal from 22f is guided through harnesses 325a and 325f.

When the A5 horizontal / A4 vertical original O passes between the detecting member 33 and the feeding roller 31, the detecting member 33 is detected.
The detection circuit 73a outputs the output Pa or Qa as shown in FIG. 125 (b) by the signals from c and 33d. When the B5 horizontal / B4 vertical document O passes between the detection member 33 and the feeding roller 31, the detection member 33
In response to the signals from b and 33e, the detection circuit 73b outputs the output Pb or Qb as shown in FIG. 125 (c), and the detection circuit 73a also outputs the output Pb.
a or Qa is output. A4 landscape / A3 portrait document O
When the paper passes between the detection member 33 and the feeding roller 31, the detection circuit 73c outputs the output P as shown in (d) of FIG. 125 by the signals from the detection members 33a and 33f.
c or Qc is output and the detection circuit 7
3a also outputs the output Pa or Qa, and the detection circuit 73b also outputs the output Pb or Qb.

The binarization circuits 79a, 79b, 79c binarize the detection signals from the corresponding detection circuits 73a, 73b, 73c.

By the way, each of the binarization circuits 79a, 79b, 7
The method of determining the threshold value of 9c is as follows.

FIG. 127 shows output signals of the detection circuits 73a, ... In the respective states. In this case, as the thickness increases, the outputs of the detection circuits 73a, ... Are shown to move downward in the figure. (A) shows the outputs of the detection circuits 73a, ... When there is no sheet. (C)
Indicates an output when a document O having a minimum thickness within the specifications that can be inserted into the automatic document feeder 20 is sandwiched. (D)
Indicates an output when a document O having the maximum thickness within the specifications that can be inserted into the automatic document feeder 20 is sandwiched.

The detection circuits 73a, ... Have a change range of the output in each state, which is shown in {}.

As can be seen from this figure, the threshold value is set in the case of (c) in consideration of some margin from the minimum value inserted into the automatic document feeder 20.
A value that does not overlap with the output range may be used.

Also, assuming that a document O outside the specified range is sandwiched by the automatic document feeder 20, the threshold value is set to a lower value in the figure in which a margin is included in the output range of (a). May be set. That is, in this case, (b) becomes the threshold value.

Setting the threshold value as described above eliminates the possibility of erroneous detection.

Therefore, as shown in Table 14, the control section 61 determines that the size of the original O is A4 landscape or A3 portrait when the outputs of the binarization circuits 79a, 79b, 79c are all at "L" level. And binarization circuits 79a, 79
When the output of b is "L" level and the output of the binarization circuit 79c is "H" level, it is determined that the size of the original O is B5 horizontal or B4 vertical and the output of the binarization circuit 79a is "B". When the outputs of the L "level and the binarization circuits 79b and 79c are at the" H "level, it is determined that the size of the document O is A5 landscape or A4 portrait.

The discrimination among the groups 1 to 3 may be made based on the detection result of the length detection circuit 75.

[0638]

[Table 14] By dividing and arranging a plurality of conductive layers or pressure-sensitive conductive rubbers in the direction orthogonal to the feeding direction of the document O to be fed, the size can be easily detected by the output of the binarizing circuit 79a. Becomes Further, in this case, since it is not necessary to compare with the reference data, it is not necessary to store several kinds of data in the memory.

Further, as described in the description of FIG. 124, the divided conductive layers 321a, ... Or pressure-sensitive conductive rubbers 322a, .. In the direction orthogonal to the direction in which the original O is fed. If the lengths are the same, one threshold value may be used.

As shown in FIGS. 124 and 128, the original O
When a plurality of detection members 33a, ... Are arranged corresponding to each size of, the following configuration can be adopted. That is, when the document O is skewed as shown in FIG. 128, the detection members 3 near both ends of the paper feed roller 31.
From 3a and 33f, a change in output will occur. When skew occurs, the earlier the document is detected, the more the original O
However, it is possible to prevent the front end from being damaged due to contact with the side frame of the automatic document feeder 20.

Therefore, any one of the plurality of detection members 33a, ... Corresponding to each size may detect the skew when the output difference occurs.

FIG. 130 shows a schematic block diagram of the skew detection circuit in this case.

That is, the exclusive OR output of the EXOR gates 80a to 80c of the outputs of the binarization circuits 79a to 79f of the detection circuits 73a to 73f is "L" when the original O is skewed as described above. "Output level. In this case, the detection circuit 73a outputs the voltage value corresponding to the resistance value change from the pressure-sensitive conductive rubber 322a corresponding to the detection member 33a, and the detection circuit 73b outputs the detection member 33.
The voltage value corresponding to the resistance value change from the pressure-sensitive conductive rubber 322b corresponding to b is output, and the detection circuit 73c outputs the voltage value corresponding to the resistance value change from the pressure-sensitive conductive rubber 322c corresponding to the detection member 33c. The detection circuit 73d outputs a voltage value corresponding to the resistance value change from the pressure-sensitive conductive rubber 322d corresponding to the detection member 33d, and the detection circuit 73e outputs
The detection circuit 73f outputs a voltage value corresponding to the resistance value change from the pressure-sensitive conductive rubber 322e corresponding to the detection member 33e.
Outputs a voltage value corresponding to a resistance value change from the pressure-sensitive conductive rubber 322f corresponding to the detection member 33f.

Further, the outputs of the EXOR gates 80a-80c, which are the outputs of the binarization circuits 79a, ..., Are supplied to the NOR gate 80d. This NOR gate 80d is
If any of the outputs of the EXOR gates 80a to 80c is at the "L" level, the "L" level is output. The skew is detected by reading this with the control unit 61. At this point, the control unit 61 outputs a command to stop the paper feeding operation.

Further, the skew detection may be performed only when the original O exists.

FIG. 131 is a schematic block diagram of the skew detection circuit.

The outputs of the detection circuits 73a and 73b are converted into digital data by the A / D converters 74a and 74b, respectively, and then sent to the comparator 312. The outputs of the detection circuits 73a and 73b are the binarization circuit 7 respectively.
9a and 79b. Binarization circuits 79a, 7
The output of 9b is input to the NOR gate 313.

When the original O is sandwiched between the aligning roller 34 and the feeding rotary member 35, the outputs of the binarizing circuits 79a and 79b change from "H" level to "L" level.

When the original O is skewed and either of the detection circuits 73a and 73b detects the presence of the original O, the skews cannot be detected unless both outputs are compared. Therefore, either of the detection circuits 73a, 73a
When the output of 3b becomes "L" level, the comparator 31
The second CS terminal may be set to the “L” level. This NOR
The output of gate 313 can be represented in Table 15 below.

[0650]

[Table 15] Therefore, in this way, each of the binarization circuits 79a, 79a,
The output of 79b may be supplied to the NOR gate 313 to control the operation of the comparator 312.

The comparison result of DATA A and DATA A'as the outputs of the A / D converters 74a and 74b compared by the comparator 312 is as follows.
Output to.

DATA A = DATA A ′ → “H” level DATA A ≠ DATA A ′ → “L” level The controller 61 may read this to detect the skew.

The comparator also outputs the output of the NOR gate, the interrupt signal of the control unit 61, and the A of the I / O READ signal.
It is also possible to take an ND output and output a signal to the control unit 61 when all are valid.

Regarding the determination of the double feed, as shown in FIG. 132, the output of the detection circuit 73a which operates even when the smallest original O is inserted into the automatic document feeder 20 is set to A
If it is supplied to the double feed determination circuit 314 via the / D converter 74a, it is possible to determine the double feed.

[0655] Also, in order to detect skew early,
It is also possible to adopt a configuration in which the skew detection signal is generated when the skew is detected by any one of the combinations of the conductive layers 300a to 300f divided into a plurality of parts.

An example of this case will be described below.

As shown in FIG. 124, the signals from the pressure-sensitive conductive rubbers 322a, ... Inside the detection members 33a, .. Are sent to the three skew detection circuits shown in FIG.

In this case, the detection circuit 73a is connected to the detection member 3
3c outputs the voltage value corresponding to the resistance value change from the pressure-sensitive conductive rubber 322c, and the detection circuit 73b outputs the voltage value corresponding to the resistance value change from the pressure-sensitive conductive rubber 322d corresponding to the detection member 33d. The detection circuit 73c outputs the voltage value corresponding to the resistance value change from the pressure-sensitive conductive rubber 322b corresponding to the detection member 33b, and the detection circuit 73d.
Outputs a voltage value corresponding to a resistance value change from the pressure-sensitive conductive rubber 322e corresponding to the detection member 33e, and the detection circuit 7
3e is a pressure-sensitive conductive rubber 322 corresponding to the detection member 33a.
The voltage value corresponding to the resistance value change from a is output, and the detection circuit 73f causes the pressure-sensitive conductive rubber 3 corresponding to the detection member 33f.
The voltage value corresponding to the resistance value change from 22f is output.

The outputs of the detection circuits 73a and 73b are converted into digital data by the A / D converters 74a and 74b, respectively, and then sent to the comparator 312a. The outputs of the detection circuits 73c and 73d are respectively converted into A / D. D converter 74
After being converted into digital data by c and 74d, it is sent to the comparator 312b, and the outputs of the detection circuits 73e and 73f are converted into digital data by the A / D converters 74e and 74f, respectively, and then to the comparator 312c. Sent.

The outputs of the detection circuits 73a to 73f are connected to the respective binarization circuits 79a to 79f.

The output of the binarization circuits 79a and 79b is NO.
It is supplied to the R gate 80a and binarized circuits 79c and 79d.
Is output to the NOR gate 80b, and the outputs of the binarizing circuits 79e and 79f are supplied to the NOR gate 80c. As a result, when either of the detection circuits of the skew detection circuits detects the presence of the document O, the comparator operates.

When the skew is detected by each skew detection circuit, the respective comparators 312a, ...
Output level. Comparator 312 of each skew detection circuit
The outputs of a, ... Are further input to the NOR gate 80d.

As for the output of the NOR gate 80d, the output of the comparators 312a, ... Of any of the skew detection circuits is "L".
If it is a level, it becomes the “L” level. The control unit 61 may detect the read skew.

To detect the double feed, as described above, only the output from the A / D converter 74a corresponding to the detection circuit 73a may be input to the double feed detection circuit 314. This is shown in FIG.
5, shown in FIG. FIG. 136 shows an embodiment in which the size can be detected.

[0665]

As described above in detail, according to the present invention,
The pressure-sensitive conductive rubber in the detection member provided downstream of the separating means is used, and the change in the thickness of the paper sheet is converted into an electric signal to detect skew, double feeding, etc. Immediately after the sheets are separated by the means, the skew or double feeding of the sheets can be surely detected, and the image reading operation or the image forming operation can be detected immediately after the skew or double feeding, and the recovery can be easily performed. A leaf feeding device can be provided.

Further, since the double feed can be detected immediately after the occurrence of the double feed, the recovery after the occurrence of the problem becomes possible immediately.

[0667] By converting the change in the resistance value associated with the displacement amount of the pressure-sensitive conductive rubber into a voltage or current value, the change amount in the thickness of the paper sheet can be detected.

Since the supporting plate also serves as a part of the electrode, the number of parts can be reduced and the reliability can be secured by the simple structure.

By providing a layer using conductive ink on a part of the surface that abuts the paper feed roller, it is possible to prevent damage to the paper feed roller when the signal detection electrode is formed of a metal member.

By forming electrodes on a part of the surface of the detection member that comes into contact with the paper feed roller with a flexible substrate, connection of signal lines can be facilitated by soldering.

By providing an electrode layer between the support plate and the surface of the detection member that contacts the paper feed roller, damage to the electrode layer due to contact with the paper feed roller can be prevented.

When the intermediate electrode is made of metal, the detection member can be integrally molded including the electrode, which can reduce the cost of manufacturing parts and improve the mechanical strength between the electrode and rubber.

Wear of the electrode layer can be prevented by forming the protective layer on the side of the conductive layer which is in contact with the sheet feeding roller. In addition, it is possible to prevent the paper feed roller from being damaged / abraded as in the case where the electrode layer is made of metal.

With the structure in which the pressure-sensitive conductive rubber is pressed through the lever, it becomes easy to create the optimum pressing condition for the detection function by setting the lever ratio.

By distributing the applied pressure by the pressure-sensitive conductive rubber and the auxiliary spring, the degree of freedom for creating the optimum pressurizing condition for the function of detecting the thickness of the paper sheet is expanded. For example, when a region in which the resistance value changes sufficiently with respect to the amount of displacement can be obtained only when the initial pressure is applied, it is possible to set a state in which a detection response is possible by pressurizing with an auxiliary spring.

Even if the pressure-sensitive conductive rubber deviates from the optimum region of the detection response due to fatigue due to aging, the pressure-sensitive conductive rubber is applied again by adjusting the thickness of the pressure-sensitive conductive rubber under pressure. It is possible to restore the pressure state to the condition that allows the optimum response. At the same time, the degree of freedom of initial setting conditions increases.

By arranging a plurality of detecting members in the width direction, it becomes possible to detect skew of the paper sheet.

By arranging a plurality of detecting members in a direction orthogonal to the paper sheet feeding direction, skew can be detected by comparing signals from a plurality of pressure-sensitive conductive rubbers. If only the pressure-sensitive conductive rubber or the conductive layer is divided, a plurality of signals can be output from one detection member. Therefore, the number of parts does not increase.

By making the areas equal, it becomes possible to compare the detected values of both. When the areas are different, the detected values are different from each other, so that the skew cannot be detected.

Also, by arranging a plurality of detecting members, skew can be detected, and by using separate members, if one side cannot obtain a desired output value due to aging, only one can be replaced. . Therefore, the burden on the user at the time of replacement is reduced.

By detecting the double feed with the first sheet as a reference, it is possible to cope with any type of sheet inserted into the feeding device. In the method of storing the reference data in the memory, the types of paper sheets to be supported are limited due to the limited memory capacity. Moreover, since it is not necessary to temporarily store the reference data in the memory, the burden on the user can be reduced.

By comparing the detected value of the thickness of the first sheet and the detected value of the thickness of the second sheet, it is possible to detect the double feeding in the feeding state.

If the reference data is not updated when it is determined that the first sheet has been double-fed, detection after restart is impossible and can be prevented.

[0684] By clearing the data of the reference paper sheet when there are no paper sheets remaining in the paper feed tray, even if several kinds of paper sheets are inserted into the feeding device, it is possible to cope with the situation. . Even in the case where different types of paper sheets are mixed in a set of a plurality of paper sheets, the previous data is not used as a reference, and therefore accurate detection can be performed.

When the second and subsequent paper sheets are double-fed, the first data, which is the reference data, is held in the storage means, thereby eliminating the complexity of updating the reference data. Further, at the time of restarting after the double feeding, it is possible to detect the first double feeding of the restart. That is, the double feed can be detected at an early stage.

By counting the number of sheets after passing the separating function and displaying the counted number of sheets before the double feeding when the second and subsequent sheets are double fed, it is possible to restart from the middle of the double feeding detection. That is, it is not necessary to restart from the first sheet, and the burden on the user can be reduced.

If the reference data is stored in the memory and the feeding state is detected, it is not necessary to detect the double feed of the first sheet by comparing with the second and subsequent sheets. That is, it is possible to immediately detect when the first sheet is double-fed.

By storing the reference data in the memory according to the target paper sheets, it is possible to deal with several kinds of paper sheets.

When one type of paper such as a slip or securities is predetermined, storing the data once saves the user from having to input the reference data. In addition, the circuit does not become complicated as when using RAM, etc., and inexpensive double feed detection is possible.

[0690] Separation by the separation brake is performed, and when only one sheet is sandwiched by the separation brake, accurate double feed can be detected by detecting.

By sampling the thickness of a sheet of paper a plurality of times and storing the maximum value in the memory as reference data, that is, by detecting the maximum thickness of a sheet of paper,
Even in the case where the thickness of the paper sheets is partially different at the time of double feeding, the double feeding can be detected.

[0692] The feeding mechanism is in an operable state.
That is, by using the detection output of the state in which the pressure-sensitive conductive rubber is pressed when the feeding mechanism is in the closed state as a reference, the open / close detection circuit of the feeding mechanism can be omitted.

If the feeding device operates when the feeding mechanism is opened, it may cause malfunction and may cause damage such as injury to irradiation. It is possible to prevent this by stopping the feeding operation in the opened state.

[Brief description of drawings]

FIG. 1 is a sectional view showing a schematic configuration of a copying machine as an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing a schematic configuration of a document scanning unit.

FIG. 3 is a diagram for explaining a document conveying operation.

FIG. 4 is a diagram for explaining a document conveying operation.

FIG. 5 is a diagram for explaining a document conveying operation.

FIG. 6 is a diagram for explaining a document conveying operation.

FIG. 7 is a diagram for explaining a document conveying operation.

FIG. 8 is a block diagram schematically showing a configuration of a control circuit of the image forming apparatus.

FIG. 9 is a diagram for explaining a detection member and a paper feed roller.

FIG. 10 is a view for explaining a main part of a detection member.

FIG. 11 is a view for explaining a main part of a detection member.

FIG. 12 is a diagram showing a relationship between a typical pressure of a pressure-sensitive conductive rubber and a resistance value.

FIG. 13 is a diagram showing a relationship between a typical pressure and a resistance value of pressure-sensitive conductive rubber.

FIG. 14 is a diagram showing a relationship between a typical pressure of a pressure-sensitive conductive rubber and a resistance value.

FIG. 15 is a circuit diagram showing a schematic configuration of a detection circuit.

FIG. 16 is a diagram for explaining a separated and fed state of a document.

FIG. 17 is a diagram for explaining a separated and fed state of a document.

FIG. 18 is a diagram for explaining another configuration example of the detection member.

FIG. 19 is a diagram for explaining another configuration example of the detection member.

FIG. 20 is a diagram for explaining another configuration example of the detection member.

FIG. 21 is a diagram for explaining another configuration example of the detection member.

FIG. 22 is a diagram for explaining another configuration example of the detection member.

FIG. 23 is a diagram for explaining another configuration example of the detection member.

FIG. 24 is a block diagram showing a control circuit provided with a length detection circuit.

FIG. 25 is a block diagram showing a schematic configuration of a length detection circuit.

FIG. 26 is a timing chart showing an output waveform of a main part of the length detection circuit.

FIG. 27 is a flowchart for explaining a double feed detection operation when feeding a document.

FIG. 28 is a flowchart for explaining a double feed detection operation when feeding a document.

FIG. 29 is a block diagram showing a control circuit provided with a length detection circuit.

FIG. 30 is a timing chart of a chip select signal for a preset signal, an output of a binarization circuit, and a delay pulse.

FIG. 31 is a flowchart for explaining a double feed detection operation when feeding a document.

FIG. 32 is a flowchart for explaining a double feed detection operation when feeding a document.

FIG. 33 is a block diagram showing a control circuit provided with a thickness detection circuit.

FIG. 34 is a block diagram showing a schematic configuration of a thickness detection circuit.

FIG. 35 is a flowchart for explaining a double feed detection operation when feeding a document.

FIG. 36 is a flowchart for explaining a double feed detection operation when feeding a document.

FIG. 37 is a block diagram showing a control circuit provided with a thickness detection circuit.

FIG. 38 is a flowchart for explaining a double feed detection operation when feeding a document.

FIG. 39 is a flow chart for explaining a double feed detection operation when feeding a document.

FIG. 40 is a block diagram showing a control circuit provided with a length detection circuit and a thickness detection circuit.

FIG. 41 is a flowchart for explaining a double feed detection operation when feeding a document.

FIG. 42 is a flowchart for explaining a double feed detection operation when feeding a document.

FIG. 43 is a diagram for explaining a document conveyance state and an output signal corresponding to a document thickness.

FIG. 44 is a block diagram showing a schematic configuration of a control circuit provided with a peak detection circuit.

FIG. 45 is a block diagram showing a schematic configuration of a peak detection circuit.

FIG. 46 is a timing chart for explaining counter output for binary output.

FIG. 47 is a timing chart for explaining sampling of the first and second originals.

FIG. 48 is a diagram for explaining a conveyance state of a reference document, a cut-and-pasted document, and a multi-fed document and sampling for each document.

FIG. 49 is a flowchart for explaining a double feed detection operation when feeding a document.

FIG. 50 is a flowchart for explaining a double feed detection operation when feeding a document.

FIG. 51 is a flowchart for explaining a double feed detection operation when feeding a document.

FIG. 52 is a block diagram showing a schematic configuration of a thickness detection circuit provided with a minimum value detection circuit.

FIG. 53 is a view for explaining a document conveyance state and a minimum value detection point.

FIG. 54 is a flowchart for explaining a double feed detection operation when feeding a document.

FIG. 55 is a flowchart for explaining a double feed detection operation when feeding a document.

FIG. 56 is a diagram showing a schematic configuration of another example of the thickness detection circuit.

FIG. 57 is a flow chart for explaining a double feed detection operation when feeding a document.

FIG. 58 is a flowchart for explaining a double feed detection operation when feeding a document.

FIG. 59 is a diagram showing a schematic configuration of another example of the thickness detection circuit.

FIG. 60 is a diagram showing a schematic configuration of another example of the thickness detection circuit.

FIG. 61 is a diagram showing a schematic configuration of another example of the length detection circuit.

FIG. 62 is a diagram showing a schematic configuration of another example of the length detection circuit.

FIG. 63 is a view showing an equivalent circuit of a feeding rotating body.

FIG. 64 is a view showing an output example of a comparator corresponding to a document size.

FIG. 65 is a block diagram showing a schematic configuration of another example of the thickness detection circuit.

FIG. 66 is a block diagram showing a schematic configuration of another example of the thickness detection circuit.

FIG. 67 is a flowchart for explaining a document size detecting operation and a multi-feed detecting operation when feeding a document.

FIG. 68 is a flowchart for explaining a document size detecting operation and a multi-feed detecting operation when feeding a document.

FIG. 69 is a flowchart for explaining a document size detecting operation and a multi-feed detecting operation when feeding a document.

FIG. 70 is a block diagram showing a schematic configuration of another example of the length detection circuit.

71 is a block diagram showing a schematic configuration of another example of the thickness detection circuit. FIG.

FIG. 72 is a block diagram showing another example of the control circuit provided with the thickness detection circuit.

FIG. 73 is a diagram showing a document size input screen when data is input on the display unit.

FIG. 74 is a diagram showing a reference document insertion guide screen on the display unit.

FIG. 75 is a diagram showing a data registration guide screen on the display unit.

FIG. 76 is a diagram for explaining a storage example of data of each size in the RAM.

FIG. 77 is a block diagram showing a schematic configuration of another example of the length detection circuit.

FIG. 78 is a diagram for explaining an example of storage of data of each size in the RAM.

FIG. 79 is a diagram showing a schematic configuration of another example of the length detection circuit.

FIG. 80 is a diagram for explaining an example of storing data of each size in the RAM.

FIG. 81 is a diagram for explaining an example of storing data of each size in the RAM.

FIG. 82 is a view showing an input document selection screen on the display unit.

FIG. 83 is a diagram showing a document size input screen on the display unit.

FIG. 84 is a diagram showing a reference document insertion guide screen on the display unit.

FIG. 85 is a view showing a data registration guide screen on the display unit.

FIG. 86 is a flowchart for explaining a mode switching operation.

FIG. 87 is a flowchart for explaining a data registration operation.

FIG. 88 is a flowchart for explaining the operation in the normal mode.

FIG. 89 is a flowchart for explaining operations in normal mode.

FIG. 90 is a flowchart for explaining operations in a normal mode.

FIG. 91 is a timing chart showing an output waveform of the main part of the length detection circuit.

FIG. 92 is a timing chart showing an output waveform of the main part of the length detection circuit.

FIG. 93 is a view for explaining a document conveyance state and output signals corresponding to the document thickness and the conveyance state.

FIG. 94 is a block diagram showing a schematic configuration of a skew detection circuit.

FIG. 95 is a timing chart showing an output example of each sampling pulse for a binarized output.

FIG. 96 is a view for explaining three states (conditions) with respect to the detecting means.

FIG. 97 is a diagram for explaining output signals from the detection circuit in three states (conditions) with respect to the detection means.

FIG. 98 is a view showing a test mode selection screen of the display unit.

FIG. 99 is a diagram showing a cover confirmation guide screen of the display unit.

FIG. 100 is a diagram for explaining an example of storing data of each size in a RAM.

FIG. 101 is a diagram showing a registration guidance screen of standard state data on the display unit.

FIG. 102 is a flowchart for explaining an opening / closing detection operation of the automatic document feeder.

103 is a block diagram showing an example of a circuit for detecting the open / closed state of the automatic document feeder. FIG.

FIG. 104 is a cross-sectional view showing a released state of the automatic document feeder.

FIG. 105 is a block diagram showing a schematic configuration of a thickness detection circuit as a double feed detection circuit.

FIG. 106 is a timing chart showing a signal waveform of a main part of the thickness detection circuit.

FIG. 107 is a diagram showing a reference document insertion guide screen on the display unit.

FIG. 108 is a timing chart for illustrating operation of a latch circuit.

FIG. 109 is a diagram showing a data registration guide screen on the display unit.

110 is a timing chart showing a signal waveform of a main part of the thickness detection circuit. FIG.

FIG. 111 is a block diagram showing a schematic configuration of a thickness detection circuit as a double feed detection circuit.

FIG. 112 is a block diagram showing a schematic configuration of various timing generation circuits.

FIG. 113 is a timing chart showing a signal waveform of a main part of the thickness detection circuit.

FIG. 114 is a block diagram showing a schematic configuration of various timing generation circuits.

FIG. 115 is a timing chart showing a signal waveform of a main part of the thickness detection circuit.

FIG. 116 is a diagram for explaining an address determination process of sampled data.

FIG. 117 is a perspective view showing another configuration example of the detection means.

FIG. 118 is a perspective view showing another configuration example of the detection means.

FIG. 119 is a cross-sectional view showing another configuration example of the detection means.

FIG. 120 is a diagram illustrating an example of a structure of a detection unit and an output signal of a detection circuit.

FIG. 121 is a diagram illustrating an example of a structure of detection means and an output signal of a detection circuit.

FIG. 122 is a block diagram showing a schematic configuration of a skew detection circuit.

FIG. 123 is a cross-sectional view showing another configuration example of the detection means.

FIG. 124 is a cross-sectional view showing another configuration example of the detection means.

FIG. 125 is a diagram for explaining a signal detection state from the detection means.

FIG. 126 is a cross-sectional view showing another configuration example of the detection means.

FIG. 127 is a block diagram showing a schematic configuration of a size detection circuit.

FIG. 128 is a diagram showing an output signal in each state of the detection circuit.

FIG. 129 is a block diagram showing a schematic configuration of a skew detection circuit.

FIG. 130 is a block diagram showing a schematic configuration of a skew detection circuit.

131 is a block diagram showing a schematic configuration of a skew / double feed detection circuit. FIG.

FIG. 132 is a block diagram showing a schematic configuration of a skew detection circuit.

FIG. 133 is a block diagram showing a schematic configuration of a skew / double feed detection circuit.

FIG. 134 is a block diagram showing a schematic configuration of a skew, double feed, and size detection circuit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Copier main body O ... Original document 20 ... Automatic original feeding device 25 ... Paper feeding path 26 ... Separation member 31 ... Paper feeding roller 33 ... Detection member 33a ... Pressure-sensitive conductive rubber 51 ... Main control unit 52 ... Operation panel 61 ... Control Part 73 ... Detection circuit 74 ... A / D converter 76 ... Thickness detection circuit

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[Procedure amendment]

[Submission date] July 27, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0618

[Correction method] Change

[Correction content]

[0618]

[Table 13] When the document O is skewed, it is in the state of 2 or 3, so the control unit 61 may detect the skew when the output of the EXOR gate 80 becomes the “L” level. At this time, the control unit 61 stops the paper feeding operation.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0638

[Correction method] Change

[Correction content]

[0638]

[Table 14] By dividing and arranging a plurality of conductive layers or pressure-sensitive conductive rubbers in the direction orthogonal to the feeding direction of the document O to be fed, the size can be easily detected by the output of the binarizing circuit 79a. Becomes Further, in this case, since it is not necessary to compare with the reference data, it is not necessary to store several kinds of data in the memory.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0655

[Correction method] Change

[Correction content]

[0655] Also, in order to detect skew early,
It is also possible to adopt a configuration in which a skew detection signal is generated when a skew is detected by any one of the combinations of the detection members 33a and 33f divided into a plurality of parts.

Claims (10)

[Claims] 1. A storage means for storing a plurality of paper sheets, a transport means for transporting the paper sheets, and a paper sheet stored in the storage means is taken out one by one and supplied to the transport means. Take-out means, a feed rotation means provided on the conveying means for feeding the paper sheets taken out by the take-out means, and a rotation direction of the feed rotation means that is in contact with the feed rotation means. By rotating in the opposite direction to the separating means for separating the second and subsequent sheets taken out by the taking-out means from the first sheet, and downstream of the separating means on the conveying means. And a pressure sensitive conductive rubber that is in contact with the feeding rotation means and has a resistance value that changes with the applied pressure. The pressure sensitive conductive rubber corresponds to the pressure associated with feeding the paper sheet. Output means for outputting a change in resistance value of Paper feeding device for collection. 2. The pressure-sensitive conductive rubber is pressed against the feed rotation means by a support plate, and the support plate is used as an electrode for detecting a signal from the pressure-sensitive conductive rubber. The paper sheet feeder according to claim 1. 3. A part of the surface of the pressure-sensitive conductive rubber which comes into contact with the feeding / rotating means is an electrode formed of a thick film printing layer made of conductive ink mixed with conductive particles, and the pressure-sensitive conductive rubber is The paper sheet feeder according to claim 1, wherein the paper sheet feeder is used as an electrode for detecting a signal from a conductive rubber. 4. A storage means for storing a plurality of paper sheets, a conveying means for conveying the paper sheets, and a paper sheet stored in the storage means is taken out one by one and supplied to the conveying means. Take-out means, a feed rotation means provided on the conveying means for feeding the paper sheets taken out by the take-out means, and a rotation direction of the feed rotation means that is in contact with the feed rotation means. By rotating in the opposite direction to the separating means for separating the second and subsequent sheets taken out by the taking-out means from the first sheet, and downstream of the separating means on the conveying means. And a pressure sensitive conductive rubber that is in contact with the feeding rotation means and has a resistance value that changes with the applied pressure. The pressure sensitive conductive rubber corresponds to the pressure associated with feeding the paper sheet. Output means for outputting the change in resistance value of First detecting means for detecting an electric signal corresponding to a change in resistance value of the pressure-sensitive conductive rubber, and second for detecting a conveyance state of paper sheets by the electric signal detected by the first detecting means. A sheet feeding device, characterized by comprising: 5. The paper sheet feeding apparatus according to claim 4, wherein the second detecting means detects double feeding of the paper sheets as a conveyance state of the paper sheets. 6. The second detecting means is for detecting the size of a sheet to be fed by an electric signal detected by the first detecting means.
The paper sheet feeder according to. 7. The method according to claim 4, wherein the second detecting means detects the skew of the paper sheet to be fed by the electric signal detected by the first detecting means. Paper sheet feeder. 8. The output means is composed of a conductive rubber whose resistance value changes with pressure applied to an indicating member which is one electrode, and an electrode layer which is the other electrode,
The sheet feeding device according to claim 4, wherein the pressure-sensitive conductive rubber or electrode layer is divided into a plurality of parts in a direction orthogonal to the feeding direction of the feeding rotation means. 9. The paper sheet feeding apparatus according to claim 6, wherein a plurality of the output means are arranged in correspondence with the position where the size of the paper sheet is detected. 10. The paper sheet feeding apparatus according to claim 7, wherein a plurality of the output means are arranged in correspondence with positions where skew of the paper sheet is detected.