JP2018052709A - Sheet material conveyance device, image reading device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent occurrence of such a situation that start timing of sheet material conveyance is delayed due to execution of multi-feeding detection abnormality determination control.SOLUTION: In a sheet material conveyance device which includes: separation and feed means 80, 84, 85 of feeding only one sheet material by separating the one sheet material from among the plural sheet materials that are stored in a sheet material storage part 53 when receiving a sheet material feed command; multi-feeding detection means 530 of detecting whether or not such multi-feeding that the plural sheet materials are fed by the separation and feed means occurs on a prescribed multi-feeding detection place on a conveyance path of the sheet material fed from the separation and feed means; and control means of executing multi-feeding detection abnormality determination control for determining presence/no presence of abnormality of the multi-feeding detection means, the control means starts the multi-feeding detection abnormality determination control after receiving the sheet material feed command, and finishes the multi-feeding detection abnormality determination control before the sheet material is conveyed to the multi-feeding detection place.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a sheet material conveying apparatus, an image reading apparatus, and an image forming apparatus.

  Conventionally, when a sheet material sending command is received, in a sheet material conveying apparatus that separates and sends a single sheet material from a sheet material container by a separating and sending means, a double feed detecting means for detecting whether or not a double feed has occurred. A device that executes double feed detection abnormality determination control for determining the presence or absence of abnormality is known.

  For example, Patent Document 1 discloses a multi-feed that determines whether or not there is an abnormality in a multi-feed detection unit in a sheet material transport apparatus that separates and sends a document (sheet material) upon receipt of a document feed signal (sheet material sending command). A device that executes detection abnormality determination control at power-on is disclosed.

  However, in the conventional sheet material conveying apparatus, the double feed detection abnormality determination control is performed in the rising control after the power is turned on. For this reason, there is a problem that the time when the sheet material can be conveyed is delayed by the time required for the double feed detection abnormality determination control.

  In order to solve the above-described problems, the present invention, upon receiving a sheet material sending command, separates one sheet material out of a plurality of sheet materials accommodated in the sheet material accommodating portion, and Separation / feeding means for feeding only the sheet material, and multiple feeds for feeding a plurality of sheet materials from the separation / feeding means are generated at a predetermined double feed detection position on a conveyance path of the sheet material sent from the separation / feeding means. In the sheet material conveying apparatus, comprising: a multi-feed detection unit that detects whether or not the multi-feed detection unit and a control unit that executes a multi-feed detection abnormality determination control that determines whether or not the multi-feed detection unit is abnormal. The multi-feed detection abnormality determination control is started after receiving the sheet material sending command, and the multi-feed detection abnormality determination control is ended before the sheet material is conveyed to the multi-feed detection portion. .

  According to the present invention, there is an excellent effect that it is possible to eliminate the situation where the start timing of sheet material conveyance is delayed due to the execution of the double feed detection abnormality determination control.

FIG. 2 is an enlarged configuration diagram showing a main configuration of an ADF of a copying machine according to the present embodiment. 2 is a schematic configuration diagram showing the copying machine. FIG. FIG. 2 is a partial configuration diagram illustrating an enlarged part of an image forming unit in the copier. FIG. 3 is a partially enlarged view showing a part of a tandem part including four process units in the image forming part. It is a control block diagram of the same ADF. It is a block diagram which shows the drive system of the same ADF. It is explanatory drawing of the state in which one original exists in the double feed detection location of the double feed detection mechanism in the ADF. FIG. 6 is an explanatory diagram of a state in which two originals MS exist at a double feed detection portion of a double feed detection mechanism in the ADF. It is a flowchart which shows an example of the double feed detection abnormality determination control in embodiment. It is a flowchart which shows the other example of double feed detection abnormality determination control in embodiment.

Hereinafter, an embodiment in which the present invention is applied to an automatic document feeder (ADF) as a sheet material conveying device of an image reading apparatus provided in an image forming apparatus such as a copying machine or a facsimile will be described.
The sheet material conveying apparatus according to the present invention is not limited to the ADF, and can be applied to a paper feeding unit that conveys a recording material such as recording paper from a paper stacking unit inside the image forming apparatus. Further, the present invention is not limited to the sheet material conveying device applied to the image forming apparatus and the image reading device, and can be widely applied as long as the sheet material conveying device conveys the sheet material.

First, the basic configuration of the copier 500 in this embodiment will be described.
FIG. 2 is a schematic configuration diagram showing the copying machine 500 of the present embodiment.
The copier 500 of this embodiment includes an image forming unit 1 as an image forming unit, a recording paper supply device 40, and an image reading unit 50 as an image reading device. The image reading unit 50 includes a scanner 150 as an image reading unit fixed on the image forming unit 1 and an ADF 51 supported by the scanner 150.

  The recording paper supply device 40 has two recording paper feed cassettes 42 arranged in multiple stages in a paper bank 41. Further, the recording paper feeding roller 43 for feeding the recording paper P from each recording paper feeding cassette 42, a recording paper separating roller 45 for separating the fed recording paper P and feeding it to the recording paper feeding path 44, etc. ing. Furthermore, the main body side recording paper feed path 37 as a recording paper conveyance path of the image forming unit 1 also includes a plurality of conveyance roller pairs 46 for conveying the recording paper P as a recording medium. Then, the recording paper P in the recording paper feed cassette 42 is fed into the main body side recording paper feed path 37 in the image forming unit 1.

  The image forming unit 1 includes an optical writing device 2 and four process units 3K, 3Y, 3M, and 3C that form toner images of black, yellow, magenta, and cyan (K, Y, M, and C). . Further, the image forming unit 1 includes a transfer unit 24, a paper transport unit 28, a registration roller pair 33, a fixing device 34, a recording paper reversing device 36, a main body side recording paper feeding path 37, and the like. The optical writing device 2 drives a light source such as a laser diode or LED disposed therein to irradiate the drum-shaped four photosensitive members 4K, 4Y, 4M, and 4C with the laser light L. By this irradiation, electrostatic latent images are formed on the surfaces of the photoreceptors 4K, 4Y, 4M, and 4C, and the latent images are developed into toner images through a predetermined development process.

FIG. 3 is a partial configuration diagram illustrating an enlarged part of the internal configuration of the image forming unit 1.
FIG. 4 is a partially enlarged view showing a part of a tandem part composed of four process units 3K, 3Y, 3M, 3C.
Since the four process units 3K, 3Y, 3M, and 3C have substantially the same configuration except that the colors of the toners to be used are different, toners K, Y, M, and C attached to the respective reference numerals in FIG. The subscript indicating the color of is omitted.

  Each of the process units 3K, 3Y, 3M, and 3C supports the photosensitive member 4 and various devices disposed around it as a single unit on a common support, and forms an image of the copying machine 500 main body. It can be attached to and detached from the part 1. One process unit 3 includes a charging device 5, a developing device 6, a drum cleaning device 15, a charge removal lamp 22, and the like around the photoconductor 4. The copying machine 500 has a so-called tandem type configuration in which four process units 3K, 3Y, 3M, and 3C are arranged so as to face an intermediate transfer belt 25, which will be described later, along the endless movement direction. Yes.

  As the photoreceptor 4, a drum-shaped member is used in which a photosensitive layer is formed by applying a photosensitive organic photosensitive material to a base tube made of aluminum or the like. However, an endless belt may be used.

  The developing device 6 develops a latent image using a two-component developer containing a magnetic carrier and a nonmagnetic toner. The developing device 6 includes a stirring unit 7 that transports the two-component developer accommodated in the developer while stirring and supplies the developer to the developing sleeve 12, and a toner in the two-component developer carried on the developing sleeve 12. 4 and a developing unit 11 for transferring to 4.

  The stirring unit 7 is provided at a position lower than the developing unit 11, and includes two conveying screws 8 arranged in parallel to each other, a partition plate provided between the two conveying screws 8, and the developing case 9. A toner concentration sensor 10 provided on the bottom surface is provided.

  The developing unit 11 includes a developing sleeve 12 that faces the photosensitive member 4 through the opening of the developing case 9, a magnet roller 13 that is non-rotatably provided inside the developing sleeve 12, a doctor blade 14 that approaches the developing sleeve 12, and the like. ing. The developing sleeve 12 has a non-magnetic rotatable cylindrical shape. The magnet roller 13 has a plurality of magnetic poles that are sequentially arranged from the position facing the doctor blade 14 toward the rotation direction of the developing sleeve 12. Each of these magnetic poles applies a magnetic force to the two-component developer on the developing sleeve 12 at a predetermined position in the rotation direction. As a result, the two-component developer sent from the stirring unit 7 is attracted and carried on the surface of the developing sleeve 12 and a magnetic brush is formed on the surface of the developing sleeve 12 along the lines of magnetic force.

  The magnetic brush is regulated to an appropriate layer thickness when passing through the position facing the doctor blade 14 as the developing sleeve 12 rotates, and then conveyed to the developing region facing the photoconductor 4. The toner is transferred onto the electrostatic latent image by the potential difference between the developing bias applied to the developing sleeve 12 and the electrostatic latent image on the photosensitive member 4 to contribute to development. Further, the two-component developer that forms a magnetic brush and is carried by the developing sleeve 12 and passes through the developing region returns to the developing portion 11 again as the developing sleeve 12 rotates. Then, after separating from the sleeve surface due to the influence of the repulsive magnetic field formed between the magnetic poles of the magnet roller 13, the magnet roller 13 is returned to the stirring unit 7. An appropriate amount of toner is supplied to the two-component developer in the stirring unit 7 based on the detection result of the toner density sensor 10. As the developing device 6, a device using a one-component developer not containing a magnetic carrier may be adopted instead of a device using a two-component developer.

  As the drum cleaning device 15, a system in which the cleaning blade 16 made of an elastic body is pressed against the photoconductor 4 is used, but another system may be used. Further, in the present embodiment, for the purpose of improving the cleaning property, a system having a contact conductive fur brush 17 whose outer peripheral surface is in contact with the photosensitive member 4 is rotatable in the direction of the arrow in the figure. The fur brush 17 also serves to apply the lubricant to the surface of the photosensitive member 4 while scraping the lubricant from the solid lubricant into a fine powder. A metal electric field roller 18 for applying a bias to the fur brush 17 is rotatably provided in the direction of the arrow in the figure, and the tip of the scraper 19 is pressed against it.

  The toner adhering to the fur brush 17 from the photoconductor 4 is transferred to the electric field roller 18 to which a bias is applied while rotating in contact with the fur brush 17 in the counter direction. The toner transferred to the electric field roller 18 is scraped off from the electric field roller 18 by the scraper 19 and falls onto the recovery screw 20. The collection screw 20 conveys the collected toner collected by the fur brush 17 and the cleaning blade 16 from the surface of the photoconductor 4 toward the end of the drum cleaning device 15 in the direction perpendicular to the drawing sheet surface, and an external recycling conveyance device. Deliver to 21. The recycle conveyance device 21 sends the collected toner that has been delivered to the developing device 6 for recycling.

  The neutralization lamp 22 neutralizes the surface of the photoreceptor 4 by light irradiation. The surface of the photoreceptor 4 that has been neutralized is uniformly charged by the charging device 5 and then subjected to optical writing processing by the optical writing device 2. In the copying machine 500, the charging device 5 is a device in which a charging roller to which a charging bias is applied is rotated while being in contact with the photoconductor 4, but a scorotron that performs a charging process on the photoconductor 4 in a non-contact manner. A charger or the like may be used.

  In FIG. 3 described above, the black, yellow, magenta, and cyan toner images are formed on the photoreceptors 4K, 4Y, 4M, and 4C of the four process units 3K, 3Y, 3M, and 3C by the processes described above. It is formed.

  A transfer unit 24 is disposed below the four process units 3K, 3Y, 3M, and 3C. The transfer unit 24 forms a primary transfer nip for K, Y, M, and C by bringing an intermediate transfer belt 25 stretched by a plurality of rollers into contact with the photoreceptors 4K, 4Y, 4M, and 4C. In the transfer unit 24, one of a plurality of rollers that stretch the intermediate transfer belt 25 is rotationally driven as a drive roller, so that the intermediate transfer belt 25 moves endlessly in the direction of arrow A (clockwise direction) in the figure. To do.

In the vicinity of each primary transfer nip, the intermediate transfer belt 25 is pressed toward the photoreceptors 4K, 4Y, 4M, and 4C by primary transfer rollers 26K, 26Y, 26M, and 26C disposed inside the belt loop. A primary transfer bias is applied to each of the primary transfer rollers 26K, 26Y, 26M, and 26C by a power source. As a result, a primary transfer electric field for electrostatically moving the toner images on the photoconductors 4K, 4Y, 4M, and 4C toward the intermediate transfer belt 25 is formed in the primary transfer nips for K, Y, M, and C. Yes.
The front surface of the intermediate transfer belt 25 that sequentially passes through the primary transfer nips for K, Y, M, and C along with the endless movement in the direction of arrow A (clockwise direction) in FIGS. First, the toner images are sequentially superposed and primary transferred at each primary transfer nip. By this primary transfer of superposition, a four-color superposed toner image (hereinafter referred to as “four-color toner image”) is formed on the front surface of the intermediate transfer belt 25.

  Below the transfer unit 24 in the figure, a paper transport unit 28 is provided between the paper transport belt drive roller 30 and the secondary transfer roller 31 to endlessly move the endless paper transport belt 29. . As shown in FIGS. 2 and 3, the intermediate transfer belt 25 and the paper are interposed between a lower transfer roller 27 and a secondary transfer roller 31, which are one of a plurality of rollers that stretch the intermediate transfer belt 25. The conveyor belt 29 is sandwiched. As a result, a secondary transfer nip is formed in which the front surface of the intermediate transfer belt 25 and the front surface of the paper transport belt 29 abut. A secondary transfer bias is applied to the secondary transfer roller 31 by a power source, and the lower stretching roller 27 is grounded. Thereby, a secondary transfer electric field is formed in the secondary transfer nip.

  A registration roller pair 33 is disposed on the right side of the secondary transfer nip in the drawing. A registration roller sensor is disposed near the entrance of the registration nip of the registration roller pair 33. The recording paper P conveyed from the recording paper supply device 40 toward the registration roller pair 33 is temporarily stopped after a predetermined time when the leading edge of the recording paper P is detected by the registration roller sensor. Touch the tip to the resist nip. As a result, the posture of the recording paper P is corrected, and preparations for synchronization with image formation are completed.

  When the leading edge of the recording paper P hits the registration nip, the registration roller pair 33 resumes roller rotation driving at a timing at which the recording paper P can be synchronized with the four-color toner image on the intermediate transfer belt 25, and the recording paper P is removed. Send to the secondary transfer nip. In the secondary transfer nip through which the recording paper P passes, the four-color toner image on the intermediate transfer belt 25 is secondarily transferred onto the recording paper P under the influence of the secondary transfer electric field and the nip pressure, Together, it becomes a full-color image. The recording paper P that has passed through the secondary transfer nip is separated from the intermediate transfer belt 25 and is conveyed to the fixing device 34 along with its endless movement while being held on the front surface of the paper conveyance belt 29.

  The transfer residual toner that has not been transferred to the recording paper P at the secondary transfer nip is attached to the front surface of the intermediate transfer belt 25 that has passed through the secondary transfer nip. The transfer residual toner is scraped and removed by the belt cleaning device 32 in which the cleaning member contacts the intermediate transfer belt 25.

  The recording paper P conveyed to the fixing device 34 is fixed with a full color image by pressurization or heating in the fixing device 34. The recording paper P on which the full-color image is fixed is sent from the fixing device 34 to the paper discharge roller pair 35 and then discharged to a paper discharge tray 501 outside the apparatus.

As shown in FIG. 2, a recording paper reversing device 36 is disposed below the paper transport unit 28 and the fixing device 34.
When performing double-sided printing, the conveyance path of the recording paper P that has undergone image fixing processing on one side is switched to the recording paper reversing device 36 side by the switching claw, where the recording paper P is reversed and again the secondary transfer nip. Enter. Then, after the image secondary transfer process and the fixing process are performed on the other side of the recording sheet P, the recording sheet P is discharged onto the discharge tray 501.

Next, the image reading unit 50 fixed on the image forming unit 1 will be described.
FIG. 1 is an enlarged configuration diagram showing a main configuration of the ADF 51.
The image reading unit 50 including the scanner 150 and the ADF 51 fixed on the scanner 150 includes two fixed image reading units and a moving reading unit 152 described later.
The image reading unit 50 can use two types of document reading methods. The first is a fixed document reading method in which the ADF 51 is opened, the document MS is placed on the second contact glass 155, the ADF 51 is closed, and the surface of the document MS is read by the moving reading unit 152. Second, the original MS is placed on the original placement table 53 provided in the ADF 51, the original MS is conveyed to the first contact glass 154 by the ADF 51, and the original is read by the fixed reading units 151 and 95. This is a reading method.

  The movable reading unit 152 is disposed directly below the second contact glass 155 fixed to the upper wall of the casing of the scanner 150 so as to come into contact with the document MS, and shows an optical system including a light source, a reflection mirror, and the like. It can be moved in the left-right direction. Then, in the process of moving the optical system from the left side to the right side in the figure, after the light emitted from the light source is reflected by the lower surface of the document MS placed on the second contact glass 155, a plurality of reflecting mirrors are The light is received by an image reading sensor 153 such as a CCD module or CIS module fixed to the scanner 150.

  On the other hand, the image reading unit 50 includes a first fixed reading unit 151 provided in the scanner 150 and a second fixed reading unit 95 provided in the ADF 51 as fixed image reading units. . A first fixed reading unit 151 including a light source, a reflection mirror, an image reading sensor such as a CCD, and the like is disposed directly below a first contact glass 154 fixed to the upper wall of the casing of the scanner 150 so as to contact the document MS. ing. Then, when the document MS conveyed by the ADF 51 passes over the first contact glass 154, image reading is performed via a plurality of reflecting mirrors while sequentially reflecting the light emitted from the light source on the first surface of the document MS. The sensor 153 receives light. Accordingly, the first surface of the document MS is scanned without moving the optical system including the light source and the reflection mirror. The second fixed reading unit 95 scans the second surface of the document MS after passing through the first fixed reading unit 151.

  The ADF 51 disposed on the scanner 150 includes a document placement table 53 for placing the document MS before reading on the main body cover 52, a document transport path 54 for transporting the document MS as a sheet material, and after reading. A document stacking table 55 for stacking the originals MS is held. The configuration of the ADF 51 in this embodiment can be broadly divided into a document setting unit, a separation feeding unit, a leading edge detection unit, a turn unit, a first reading conveyance unit, a second reading conveyance unit, a paper discharge unit, and a stack unit. .

  The document setting unit includes a document placement table 53 on which a bundle of documents MS is set so that the first surface of the document MS is upward. The leading edge of the document MS set on the document table 53 is configured to enter the cover 52 of the ADF 51. On the document placing table 53, left and right movable side guide plates 57 for mounting the document MS set on the ADF 51 in the sheet width direction orthogonal to the feeding direction are mounted. These side guide plates 57 can be relatively approached and separated so that the document placement table 53 and the center of the document MS in the width direction coincide with each other. However, the side guide plate 57 may be arranged such that only one edge of the document MS is brought into contact with one edge of the document placing table 53 and only the other edge is movable.

  The separation feeding unit separates and feeds the originals MS one by one from the set of originals MS set. In the separation feeding unit, the calling roller 80 that calls the document MS set on the document table 53 in the sheet feeding direction, and the document MS that is called by the calling roller 80 in the sheet feeding direction is directed toward the document conveyance path 54. A feed roller 85 for feeding and a separation pad 84 arranged corresponding thereto are provided.

  The document MS fed by the separation feeding unit is detected by the leading edge of the document MS coming into contact with the abutting sensor 72 of the leading edge detection unit, and then further advanced and conveyed by the first conveying roller pair 86 and the second conveying roller pair 90. Then, it is sent to the first reading conveyance unit. The first reading and conveying unit conveys the document MS on the first contact glass 154 made of platen glass. Then, while transporting, the first fixed reading unit 151 disposed in the scanner 150 reads the first surface of the document MS from below the first contact glass 154.

  The second reading / conveying unit guides the document MS that has passed the reading position by the first fixed reading unit 151 by the white guide member 96 disposed below the second fixed reading unit 95, while The two surfaces are read by the second fixed reading unit 95. The white guide member 96 serves to suppress the floating of the document MS at the second reading position by the second fixed reading unit 95 and to function as a reference white part for acquiring shading data in the second fixed reading unit 95. ing.

  The paper discharge unit discharges the document MS that has passed the reading position by the first fixed reading unit 151 and the reading position by the second fixed reading unit 95 toward the stack unit. The stack unit stacks and holds the original MS after reading on the original stack base 55.

  In the present embodiment, there is a double feed detection mechanism 530 as a double feed detection means between the first transport roller pair 86 of the tip detection unit and the second transport roller pair 90 of the turn unit, It is configured to detect the occurrence of double feed, which is a state in which a plurality of originals MS that have passed are overlapped.

FIG. 5 is a control block diagram of the entire ADF 51.
The control unit of the ADF 51 includes a controller 100 that controls a series of operations, such as a paper feed motor, various sensor units, and a fixed image reading unit 300. The paper feed motor 102 is a drive unit that drives a document transport operation, and the fixed image reading unit 300 in FIG. 5 is a first fixed reading unit 151 and a second fixed reading unit 95.

  A bundle of documents MS to be read is set on the document placing table 53 in a state where the bundle is placed so that the first surface faces upward. A set filler is swingably disposed above the document placement table 53. When the document MS is set on the document placement table 53, the position of the set filler changes. The document set sensor 63 detects this change in the position of the set filler, and this detection signal is sent to the controller 100. This detection signal is transmitted from the controller 100 to the main body control unit 111 of the image reading unit 50 via the interface circuit 107.

  The calling roller 80 that sends out the original MS from the bundle of originals MS on the original placement table 53 is driven to rotate when the drive is transmitted from the paper feed motor 102. Further, the feed roller 85 that separates and sends out only one original MS out of the originals MS sent out by the calling roller 80 is also rotationally driven by the drive transmitted from the paper feed motor 102.

  When receiving a document feed signal that is a sheet material sending command from the main body control unit 111, the controller 100 moves the calling roller 80 downward so as to approach the document placing table 53, and moves the calling roller 80 to the top of the bundle of documents MS. It is brought into contact with the upper surface of the upper document MS. The calling roller 80 can perform a so-called calling operation in which, for example, the uppermost document on the document table 53 is sent in the sheet feeding direction by rotating in the sheet feeding direction. Then, when the image reading operation of all the set originals MS is finished and the paper is discharged, the calling roller 80 moves upward so as to be separated from the original placing table 53 and stops at a predetermined standby position. . As a result, the next document MS can be set on the document table 53.

  The calling roller 80 is held by a pickup holder 81, and this pickup holder 81 is supported so as to be swingable with respect to the feed roller shaft 85a of the feed roller 85 via a bidirectional torque limiter. Thereby, when the feed roller shaft 85a of the feed roller 85 is rotationally driven in the paper feeding direction, the pickup holder 81 lowers the calling roller 80 so that the feed roller shaft 85a of the feed roller 85 is opposite to the paper feeding direction. When rotationally driven, the feed roller shaft 85a is pivoted so as to raise the calling roller 80.

  The calling roller 80 is connected to the feed roller shaft 85a via an endless belt for driving transmission, a pulley, and the like. Thus, the calling roller 80 is configured to rotate in conjunction with the rotation of the feed roller shaft 85a of the feed roller 85.

FIG. 6 is a block diagram showing a drive system of the ADF 51 in the present embodiment.
A feed roller shaft 85 a of the feed roller 85 is driven to rotate by the paper feed motor 102 and is rotated forward and reverse depending on the output rotation direction of the paper feed motor 102. Here, the forward rotation is a rotation in the direction in which the document MS is conveyed in the paper feeding direction, and the reverse rotation is a rotation in the opposite direction.

  When the output rotation direction of the paper feed motor 102 is the forward rotation direction, a rotational force in the forward rotation direction is transmitted from the paper feed motor 102 via a rotation transmission member such as a plurality of gears, and the feed roller shaft 85a is in the forward rotation direction. Rotate to. As a result, the feed roller 85 and the calling roller 80 rotate in the forward rotation direction, and the pickup holder 81 swings so that the calling roller 80 moves in a direction approaching the document MS on the document placement table 53. On the other hand, when the output rotation direction of the paper feed motor 102 is the reverse rotation direction, the rotation in the reverse rotation direction is transmitted from the paper feed motor 102 via a rotation transmission member such as a plurality of gears, and the feed roller shaft 85a rotates in the reverse rotation direction. To do. As a result, the pickup holder 81 swings and the calling roller 80 moves in a direction away from the original MS on the original table 53.

  When the feed roller shaft 85a rotates in the reverse direction, the pickup holder 81 swings upward and comes into contact with the cover 52. At this time, excessive torque transmission and rotation from the feed roller shaft 85a are blocked by the bidirectional torque limiter interposed between the feed roller shaft 85a and the pickup holder 81. As a result, the pickup holder 81 is kept in contact with the cover 52 during the reverse rotation of the paper feed motor 102.

  On the other hand, when the feed roller shaft 85a rotates in the forward direction, the pickup holder 81 swings downward, and the calling roller 80 contacts the original MS. At this time, excessive torque transmission and rotation from the feed roller shaft 85a to the pickup holder 81 are blocked by a bidirectional torque limiter interposed between the feed roller shaft 85a and the pickup holder 81. As a result, the calling roller 80 maintains a contact state with an appropriate contact pressure with respect to the document MS during normal rotation of the paper feed motor 102.

  Further, on the drive transmission path from the paper feed motor 102 to the feed roller shaft 85a, as shown in FIG. 6, a paper feed clutch 101 for switching between connection / disconnection of the drive side and the driven side is provided. Yes. By appropriately switching ON (connected, connected) / OFF (not connected, disconnected) of the paper feed clutch 101, the calling timing of the original MS, the conveyance interval (inter-paper distance), and the like are controlled. In the present embodiment, the driving force of the paper feed motor 102 is also transmitted to the first transport roller pair 86, the second transport roller pair 90, the reading exit roller pair 92, the paper discharge roller pair 93, and the like. The sheet feeding clutch 101 controls the rotation of only the feed roller 85 and the calling roller 80. The first conveying roller pair 86, the second conveying roller pair 90, the reading exit roller pair 92, the discharge roller pair 93, etc. It is always connected to the output shaft of the paper feed motor 102.

  The feeding interval of each document MS is controlled by the paper feed clutch 101. Specifically, the sheet feeding clutch is detected at a predetermined timing (timing sufficient to allow the leading edge of the document to reach the first conveying roller pair 86) after the leading edge of the document MS is detected by the abutting sensor 72. 101 is turned off. When the paper feed clutch 101 is turned off, the rotation of the feed roller 85 and the calling roller 80 is stopped. Even in this case, the document MS is conveyed by the first conveying roller pair 86 that is continuously rotated. At this time, the rear end side of the document MS is sandwiched between the separation nip between the feed roller 85 and the separation pad 84, or between the calling roller 80 and the document MS on the document placement table 53. However, since the feed roller 85 and the calling roller 80 have a built-in one-way clutch mechanism, the feed roller 85 and the calling roller 80 rotate as the document MS conveyed by the first conveying roller pair 86 moves. The document MS is conveyed without hindrance. Thereafter, when it is detected that the trailing edge of the document MS has passed the abutting sensor 72, the sheet feeding clutch 101 is turned on at a predetermined timing (a timing corresponding to a target conveyance interval). Thus, the feeding of the next original MS is started, and the next original MS is conveyed with a target conveyance interval (inter-paper distance or inter-paper time) secured with respect to the preceding original MS.

  When the user designates the double-sided reading mode or the single-sided reading mode, and the copy start button of the operation unit 108 is pressed in a state where the document MS is set on the document placing table 53, the interface circuit 107 is connected from the main body control unit 111. Then, a document feed signal which is a sheet material sending command is transmitted to the controller 100 of the ADF 51. As a result, the paper feed motor 102 starts driving in the forward direction, the calling roller 80 rotates in the forward direction, the pickup holder 81 swings downward, and the calling roller 80 contacts the document MS. . As a result, one or several (ideally one) document MS on the document placing table 53 is called (pick up), and the separation composed of the separation pad 84 and the feed roller 85 by the rotation of the call roller 80. Sent to the nip.

  When the document MS picked up by the calling roller 80 enters the separation nip, the uppermost document MS in contact with the feed roller 85 passes through the separation nip as the feed roller 85 rotates. On the other hand, the remaining original MS that has entered the separation nip is prevented from passing through the separation nip by the frictional force with the separation pad 84. As a result, even when several originals MS are picked up by the calling roller 80, only the uppermost original MS passes through the separation nip and is sent out.

  Thereafter, the leading edge of the document MS that has passed through the separation nip is detected by the abutting sensor 72, and further advances to obtain a conveyance force by the first conveyance roller pair 86, and passes through a double-feed detection point by the double-feed detection mechanism 530. . Thereafter, the conveyance force is obtained by the second conveyance roller pair 90 and is sent to the first reading conveyance unit, and the first surface of the document MS is detected by the first fixed reading unit 151 based on the detection timing of the leading edge of the document by the registration sensor 65. Read.

  The document MS that has passed through the first reading / conveying section passes through the nip of the reading exit roller pair 92 and then passes through the second reading / conveying section and is conveyed to the paper discharge section. In the single-sided reading mode in which only one side (first side) of the document MS is read, the second fixed reading unit 95 does not need to read the second side of the document MS. On the other hand, in the double-sided reading mode for reading both sides (first side and second side) of the original MS, the second fixed reading unit 95 causes the second side of the original MS to be detected based on the leading edge detection timing of the original. Read.

Next, the double feed detection mechanism 530 will be described.
FIG. 7 is an explanatory diagram of a state in which one document MS exists at the double feed detection portion of the double feed detection mechanism 530.
FIG. 8 is an explanatory diagram of a state in which two documents MS exist at the double feed detection portion of the double feed detection mechanism 530.
The double feed detection mechanism 530 in this embodiment includes an ultrasonic transmission element 531 and an ultrasonic reception element 532. The ultrasonic transmission element 531 is disposed on the inner side of the apparatus with respect to the document conveyance path 54, and the ultrasonic reception element 532 is disposed on the outer side of the apparatus with respect to the document conveyance path 54, and is disposed so as to face each other. Has been. The double feed detection portion by the double feed detection mechanism 530 is disposed downstream of the separation nip in the document conveyance direction, in this embodiment, downstream of the detection position of the abutment sensor 72 in the document conveyance direction.

  The double feed detection mechanism 530 according to the present embodiment corresponds to the intensity of the ultrasonic waves received by the ultrasonic receiving element 532 through the original MS passing through the original conveying path 54 by the ultrasonic wave transmitted from the ultrasonic transmitting element 531. Determine whether double feed or non-double feed. For example, as shown in FIG. 7, when there is only one document MS at the double feed detection portion of the double feed detection mechanism 530, the ultrasonic receiving element 532 receives strong ultrasonic waves exceeding a predetermined threshold, and An H level signal is output from the sound wave receiving element 532. On the other hand, as shown in FIG. 8, when two or more originals MS exist at the double feed detection portion of the double feed detection mechanism 530, the ultrasonic receiving element 532 receives weak ultrasonic waves having a predetermined threshold value or less. The sound wave receiving element 532 outputs an L level signal. Therefore, it is possible to determine whether the feeding is double feed or non-double feed depending on whether the output signal level of the ultrasonic receiving element 532 is H level or L level.

  Specifically, the timer counts from the timing when the leading edge of the document MS sent out from the separation nip is detected by the abutting sensor 72, and the count at which the leading edge of the document MS reaches the double feed detection position of the double feed detection mechanism 530. When the value is reached, transmission of ultrasonic waves from the ultrasonic transmission element 531 is started, and the double feed detection operation is started. More specifically, at the timing when the leading edge of the document MS reaches the double feed detection position of the double feed detection mechanism 530 and is conveyed by 25 mm, the transmission of ultrasonic waves is started and the double feed detection operation is started. . In the present embodiment, in order to make it difficult to be affected by the fluttering of the leading edge of the document MS and the deformation of the leading edge, a document leading portion corresponding to a predetermined sheet material conveyance direction length (here, 25 mm) from the leading edge of the document MS is double-fed. The double feed detection operation is prevented from being performed at the time when it exists at the detection location. In addition, it is not limited to the numerical value of 25 mm.

  Thereafter, in response to the timing at which the trailing edge of the document MS is detected by the abutting sensor 72, the transmission of ultrasonic waves is stopped, and the double feed detection operation is stopped. In the present embodiment, in order to make it less susceptible to back end fluttering and deformation of the rear end of the document MS, a predetermined sheet material conveyance direction length from the rear end of the document MS (here, the detection of the butting sensor 72). The multi-feed detection operation is prevented from being performed at the time when the trailing edge portion of the document (for the conveyance distance between the area and the multi-feed detection location) exists at the double feed detection location. The setting of the length of the rear end portion of the document is also arbitrary.

  In the present embodiment, since the ultrasonic receiving element 532 is attached to the cover 52, if the cover 52 is opened during the double feed detection operation (during document feeding), the ultrasonic transmitting element 531, the ultrasonic receiving element 532, and the like. Therefore, the double feed detection mechanism 530 determines that it is a double feed. In the present embodiment, the double feed detection mechanism 530 detects that the cover 52 has been opened before determining that it is a double feed so that even if the cover 52 is opened during the double feed detection operation. In this way, the fixed time for determining the double feed of the double feed detection mechanism 530 is set so that it can be determined that the jam is caused by the opening of the cover 52.

  Here, for example, when the double feed detection mechanism 530 breaks down or an abnormality occurs in the line connected to the double feed detection mechanism 530, there is a risk of making an erroneous determination regarding the double feed. That is, there is a possibility that it is determined that double feeding has occurred even though double feeding has not occurred, or that it has been determined that double feeding has not occurred even though double feeding has occurred. For this reason, the controller 100 according to the present embodiment executes double feed detection abnormality determination control for self-diagnosis of whether or not an abnormality has occurred in the double feed detection mechanism 530 at a predetermined double feed detection abnormality determination timing.

In the double feed detection abnormality determination control of the present embodiment, an abnormality of the double feed detection mechanism 530 is confirmed by checking the following two signal levels in a state where the document MS does not exist at the double feed detection portion of the double feed detection mechanism 530. The presence or absence of is determined.
First, it is confirmed whether the output signal of the ultrasonic receiving element 532 is at the L level (the intensity of the received ultrasonic wave is weak) in a state where no ultrasonic wave is transmitted from the ultrasonic transmitting element 531.
Second, in a state where ultrasonic waves are transmitted from the ultrasonic transmission element 531, it is confirmed whether the output signal of the ultrasonic reception element 532 is at the H level (a state where the intensity of received ultrasonic waves is strong).

  If the output signal of the ultrasonic receiving element 532 is H level in the first confirmation or the output signal of the ultrasonic receiving element 532 is L level in the second confirmation, an abnormality occurs in the double feed detection mechanism 530. Judge that you are doing. In this case, the controller 100 transmits information indicating that an abnormality has occurred in the double feed detection mechanism 530 to the main body control unit 111 via the interface circuit 107. Accordingly, the main body control unit 111 executes abnormality notification processing such as displaying a notification image for notifying abnormality of the double feed detection mechanism 530 on the screen of the operation unit 108, for example. In the present embodiment, when the controller 100 determines that an abnormality has occurred in the double feed detection mechanism 530, for example, the controller 100 executes a process of invalidating the double feed detection function. As a result, the document MS is continuously conveyed and the image reading operation is continued, but the double feed detection is not performed. The processing when it is determined that an abnormality has occurred in the double feed detection mechanism 530 is not limited to these, and is arbitrary.

  In the present embodiment, the double feed detection abnormality determination control starts after the controller 100 receives a document feed signal which is a sheet material sending command, and the document MS is conveyed to the double feed detection portion of the double feed detection mechanism 530. Exit before being done. That is, the double feed detection abnormality determination control includes the pick-up operation of the original MS from the original placement table 53 by the calling roller 80, the separation and feeding operation at the separation nip composed of the separation pad 84 and the feed roller 85, and the first transport roller. This is performed in parallel with the conveying operation of the document MS by the pair 86.

  If double feed detection abnormality determination control is executed when the device is started up, such as when the power is turned on, even if the user presses the copy start button too much, after waiting for the double feed detection abnormality determination control to end, The pick-up operation of the document MS is started. For this reason, the conveyance waiting time of the document MS is generated for the time required to execute the double feed detection abnormality determination control at the maximum. On the other hand, in the present embodiment, the pickup operation is started without waiting for the completion of the double feed detection abnormality determination control. Therefore, a waiting time for conveying the original MS due to the execution of the double feed detection abnormality determination control may occur. Absent.

  In the present embodiment, the double feed detection abnormality determination control is completed before the document MS is conveyed to the double feed detection portion of the double feed detection mechanism 530. Thus, even if an erroneous determination is made, it is possible to prevent erroneous post-processing in accordance with the erroneous determination.

  Specifically, in the present embodiment, the double feed detection abnormality determination control is executed while the calling roller 80 is moving down to pick up the first original MS sent out from the original placement table 53. However, the double feed detection abnormality determination control is executed after receiving the sheet material sending command and before the document MS is conveyed to the double feed detection portion of the double feed detection mechanism 530. May be.

FIG. 9 is a flowchart illustrating an example of double feed detection abnormality determination control in the present embodiment.
In this control example, when the controller 100 receives a document feed signal (Yes in S1), the controller 100 starts driving the feed motor 102 (S2) and starts double feed detection abnormality determination control (S3). ). As a result, the pickup holder 81 swings and the calling roller 80 descends in a direction approaching the document MS on the document placing table 53, and double feed detection abnormality determination control is executed during the descending. As described above, when the double feed detection abnormality determination control is executed while the calling roller 80 is descending, a conveyance standby time for waiting for the document conveyance until the abnormality determination operation of the double feed detection mechanism 530 is completed occurs. Nothing will happen. Therefore, the time from when the user presses the copy start button until the image of the first original MS is read can be shortened, and the first copy time until the image of the first original MS is formed on the recording paper can be reduced. Can be shortened.

  If it is determined by the double feed detection abnormality determination control that an abnormality has occurred in the double feed detection mechanism 530 (Yes in S4), the controller 100 transmits information to that effect to the main body control unit 111, and the main body control unit 111 Then, a process of displaying a double feed detection abnormality notification on the screen of the operation unit 108 is executed (S5). Then, the controller 100 continues to transport the document MS with the double feed detection function disabled, and even when the next document exists (Yes in S8), the controller 100 keeps the double feed detection function disabled. Transportation continues. Note that it may be determined that an abnormality has occurred in the double feed detection mechanism 530 when it is detected by the double feed detection abnormality determination control that an abnormality has occurred not only once but continuously a plurality of times.

  On the other hand, if it is determined by the double feed detection abnormality determination control that no abnormality has occurred in the double feed detection mechanism 530 (No in S4), the timing is adjusted to the timing at which the leading edge of the document MS is detected by the butting sensor 72. (Yes in S6), the transmission of ultrasonic waves is started from the ultrasonic transmission element 531 of the double feed detection mechanism 530, and the double feed detection operation is executed (S7). Thereafter, when there is a next original (Yes in S8), the conveyance of the original MS is continued while executing the double feed detection operation for the next original MS.

FIG. 10 is a flowchart showing another example of the double feed detection abnormality determination control in the present embodiment.
In this control example, when the controller 100 receives a document feed signal (Yes in S11), the controller 100 starts driving the feed motor 102 (S12). As a result, the pickup holder 81 swings and the calling roller 80 descends in a direction approaching the document MS on the document placing table 53, and the document MS is picked up by the rotation of the calling roller 80. When the picked-up document MS is separated into one sheet at the separation nip and the leading edge of the document MS is detected by the butting sensor 72 (Yes in S13), the double feed detection abnormality determination control is started (S13). S14).

  In this control example, the double feed detection abnormality determination control is performed after the leading edge of the document MS reaches the detection position of the abutting sensor 72 until the document MS is conveyed to the double feed detection position of the double feed detection mechanism 530. Is executed. Even when the double feed detection abnormality determination control is executed at such a timing, a conveyance waiting time for waiting for document conveyance until the abnormality determination operation of the double feed detection mechanism 530 is completed does not occur. Therefore, the time from when the user presses the copy start button until the image of the first original MS is read can be shortened, and the first copy time until the image of the first original MS is formed on the recording paper can be reduced. Can be shortened.

  When it is determined by the double feed detection abnormality determination control that an abnormality has occurred in the double feed detection mechanism 530 (Yes in S15), the controller 100 transmits information to that effect to the main body control unit 111, and the main body control unit 111 Then, a process of displaying an abnormality notification of double feed detection on the screen of the operation unit 108 is executed (S16). Then, the controller 100 continues to transport the document MS with the double feed detection function disabled, and even when the next document exists (Yes in S18), the controller 100 keeps the double feed detection function disabled with the double feed detection function disabled. Transportation continues.

  On the other hand, when it is determined by the double feed detection abnormality determination control that no abnormality has occurred in the double feed detection mechanism 530 (No in S15), the timing at which the leading edge of the document MS is detected by the abutment sensor 72 in advance. After a predetermined time has elapsed, transmission of ultrasonic waves is started from the ultrasonic transmission element 531 of the double feed detection mechanism 530, and a double feed detection operation is executed (S17). Thereafter, when there is a next original (Yes in S18), the conveyance of the original MS is continued while executing the double feed detection operation for the next original MS.

What was demonstrated above is an example, and there exists an effect peculiar for every following aspect.
(Aspect A)
When a sheet material sending command such as a document feed signal is received, one sheet material is separated from the plurality of sheet materials such as the document MS accommodated in the sheet material accommodating portion such as the document placing table 53. Separation and sending means such as a calling roller 80, a separation pad 84, and a feed roller 85 that send out only one sheet material, and a predetermined double feed detection location on a conveyance path of the sheet material sent from the separation and sending means, A multifeed detecting means such as a multifeed detecting mechanism 530 for detecting whether or not a multifeed in which a plurality of sheet materials are sent out from the separating and sending means has occurred, and a multifeed for determining whether or not there is an abnormality in the multifeed detecting means. In a sheet material conveying apparatus such as the ADF 51 provided with a control unit such as the controller 100 that executes detection abnormality determination control, the control unit opens the double-feed detection abnormality determination control after receiving the sheet material delivery command. And the sheet material to the double feed detection portion is equal to or to terminate the polymerization feed detection abnormality determination control before being transported.
In this aspect, when the sheet material sending command is received, the separating and sending means starts the separating and sending operation for separating and sending one sheet material from the sheet material container, and the sent sheet material is sent by the double feed detecting means. It is transported to a double feed detection location that detects the occurrence of double feed. The double feed detection abnormality determination control in this aspect is started after receiving the sheet material sending command, and is finished before the sheet material is conveyed to the double feed detection portion. Performed in parallel with the operation. Therefore, the separating and feeding operation and the sheet material conveying operation are performed without waiting for the end of the multi-feed detection abnormality determination control, and the situation where the start timing of the sheet material conveyance is delayed due to the execution of the multi-feed detection abnormality determination control does not occur. Just do it. Note that the double feed detection abnormality determination control is terminated before the sheet material is conveyed to the double feed detection portion, so that the erroneous double feed detection by the double feed detection means in which an abnormality has occurred is not performed.

(Aspect B)
In the aspect A, the control unit ends the double feed detection abnormality determination control before the sheet material is sent out from the sheet material container by the separation and sending unit.
According to this aspect, before the sheet material sent out by the separating and feeding means is conveyed to the double feed detection portion, the result of the double feed detection abnormality determination control can be obtained with a time margin. Thereby, for example, the necessary processing performed in response to the determination that the double feed detection unit is abnormal by the double feed detection abnormality determination control is performed before the sheet material is conveyed to the double feed detection portion. It is possible.

(Aspect C)
In the aspect B, the separating and feeding means has a contact / separation member such as a call roller 80 that can contact and separate from the sheet material accommodated in the sheet material accommodating portion. The contacting / separating member is brought into contact with the sheet material accommodated in the sheet material accommodating portion, and the sheet material is sent out by the contacting / separating member, and the control means accommodates the contacting / separating member in the sheet material accommodating portion. The double feed detection abnormality determination control is started after starting to move (lower) toward the sheet material, and before the contact / separation member contacts the sheet material accommodated in the sheet material accommodating portion, The detection abnormality determination control is terminated.
According to this aspect, before the sheet material sent out by the separating and feeding means is conveyed to the double feed detection portion, the result of the double feed detection abnormality determination control can be output with a sufficient time margin. Thereby, for example, the necessary processing performed in response to the determination that the double feed detection unit is abnormal by the double feed detection abnormality determination control is performed before the sheet material is conveyed to the double feed detection portion. It is possible.

(Aspect D)
In any one of the aspects A to C, when the sheet material sending command is received, the sheet material is on the sheet material conveyance path until the sheet material sent by the separation sending means reaches the double feed detection location. Sheet material presence / absence detection means such as an abutment sensor 72 for detecting whether there is a sheet material, and the control means detects the double feed detection abnormality when the sheet material presence / absence detection means detects that there is a sheet material. Judgment control is started.
According to this aspect, it is possible to execute the double feed detection abnormality determination control when the sheet material is actually conveyed.

(Aspect E)
In any one of the aspects A to D, the multifeed detection means includes ultrasonic waves such as the ultrasonic transmission element 531 arranged so as to face each other across the sheet material conveyance path at the multifeed detection location. It is characterized by comprising an ultrasonic receiver such as a transmitter and an ultrasonic receiver 532.
According to this aspect, it is possible to execute the double feed detection abnormality determination control for the double feed detection unit that performs double feed detection using ultrasonic waves without delaying the start timing of sheet material conveyance.

(Aspect F)
In the aspect E, the double feed detecting means determines whether or not double feed has occurred based on received signals having different values according to the intensity of the ultrasonic waves received by the ultrasonic receiver, and the control means executes The double feed detection abnormality determination control is performed based on the determination result of the reception sensitivity of the ultrasonic receiving element determined based on whether or not the received signal is higher than a predetermined threshold (signal level). Including control for determining whether or not there is an abnormality.
According to this aspect, double feed detection can be easily performed.

(Aspect G)
An image reading unit 50 including a sheet material conveying unit such as an ADF 51 that conveys a sheet material such as an original MS and an image reading unit such as a scanner 150 that reads an image on the sheet material conveyed by the sheet material conveying unit. In the image reading apparatus, the sheet material conveying device according to any one of the aspects A to F is used as the sheet material conveying unit.
According to this aspect, the double feed detection abnormality determination control for the double feed detection unit can be executed without delaying the start timing of sheet material conveyance, so the time until the image on the first sheet material is read is shortened. can do.

(Aspect H)
In an image forming apparatus such as a copier 500 comprising an image reading apparatus such as an image reading unit 50 and an image forming unit such as an image forming unit 1 that forms an image based on a read image read by the image reading apparatus. The image reading apparatus according to the aspect G is used as the image reading apparatus.
According to this aspect, since the double feed detection abnormality determination control for the double feed detection unit can be executed without delaying the start timing of sheet material conveyance, until the image on the first sheet material is formed on the recording material. Can be shortened.

DESCRIPTION OF SYMBOLS 1 Image formation part 50 Image reading unit 52 Cover 53 Original mounting stand 54 Original conveyance path 55 Original stack stand 63 Original set sensor 65 Registration sensor 72 Abutting sensor 80 Calling roller 81 Pickup holder 84 Separation pad 85 Feed roller 85a Feed roller shaft 86 First conveyance roller pair 90 Second conveyance roller pair 92 Reading exit roller pair 93 Paper discharge roller pair 95 Second fixed reading unit 96 White guide member 100 Controller 101 Paper feed clutch 102 Paper feed motor 108 Operation unit 111 Main body control unit 150 Scanner 151 First Fixed Reading Unit 152 Moving Reading Unit 153 Image Reading Sensor 154 First Contact Glass 155 Second Contact Glass 500 Copying Machine 530 Double Feed Detection Mechanism 531 Ultrasonic Transmitting Element 532 Ultrasonic Receiving Element

JP 2015-37999 A

Claims (8)

When receiving the sheet material sending command, separating and sending means for separating one sheet material out of the plurality of sheet materials housed in the sheet material housing portion and feeding only the one sheet material;
Multi-feed detection for detecting whether or not a multi-feed in which a plurality of sheet materials are sent out from the separation-and-sending means has occurred at a predetermined multi-feed detection position on the transport path of the sheet material sent out from the separate and sending means. Means,
In a sheet material conveying apparatus provided with control means for executing double feed detection abnormality determination control for determining whether there is an abnormality in the double feed detection means,
The control means starts the double feed detection abnormality determination control after receiving the sheet material delivery command, and ends the double feed detection abnormality determination control before the sheet material is conveyed to the double feed detection portion. A sheet material conveying apparatus characterized by the above. In the sheet | seat material conveying apparatus of Claim 1,
The control means ends the double feed detection abnormality determination control before the sheet material is sent out from the sheet material container by the separation and delivery means. In the sheet material conveying apparatus according to claim 2,
The separation and delivery means has a contact / separation member that can contact and separate from the sheet material accommodated in the sheet material accommodating portion, and when the sheet material delivery instruction is received, the contact / separation member is moved to the sheet material accommodation portion. The sheet material is brought into contact with the accommodated sheet material, and the sheet material is sent out by the contact / separation member,
The control means starts the double feed detection abnormality determination control after the contact / separation member starts moving toward the sheet material accommodated in the sheet material accommodation unit, and the contact / separation member is configured to be the sheet material accommodation unit. The sheet material conveying device is characterized in that the double feed detection abnormality determination control is terminated before contacting the sheet material accommodated in the sheet material. In the sheet material conveying device according to any one of claims 1 to 3,
When receiving the sheet material sending command, the sheet material presence / absence detection for detecting whether or not there is a sheet material on the sheet material conveyance path until the sheet material sent by the separation sending means reaches the double feed detection position. Having means,
The control unit starts the double feed detection abnormality determination control when the sheet material presence / absence detection unit detects that there is a sheet material. In the sheet material conveyance device according to any one of claims 1 to 4,
The multi-feed detection means includes an ultrasonic transmission unit and an ultrasonic reception unit that are arranged to face each other across the conveyance path of the sheet material at the multi-feed detection point. apparatus. In the sheet | seat material conveying apparatus of Claim 5,
The double feed detection means determines the presence or absence of occurrence of double feed based on received signals having different values according to the intensity of ultrasonic waves received by the ultrasonic receiving unit
The double feed detection abnormality determination control executed by the control means is based on the determination result of the reception sensitivity of the ultrasonic receiving element, which is determined based on whether or not the received signal is higher than a predetermined threshold. A sheet material conveying apparatus comprising: control for determining presence / absence of abnormality of the means. Sheet material conveying means for conveying the sheet material;
In an image reading apparatus comprising image reading means for reading an image on a sheet material conveyed by the sheet material conveying means,
An image reading apparatus using the sheet material conveying device according to claim 1 as the sheet material conveying unit. An image reader;
In an image forming apparatus comprising image forming means for forming an image based on a read image read by the image reading apparatus,
An image forming apparatus using the image reading apparatus according to claim 7 as the image reading apparatus.

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