Sheet conveyance device, automatic document feeder, image reading device, and image forming device

Abstract

To provide a sheet conveying device, an automatic manuscript conveying device, an image reading device and an image forming device with which the devices can be kept from getting larger and cost from increasing.SOLUTION: Metal detecting means includes an electromagnet 801 serving as magnetic force generating means, and a contact member 802 with which a metal piece m such as a staple needle and a clip attached to a manuscript MS such as a sheet attracted by the electromagnet 801 is brought into contact. In addition, it has a sound collecting microphone 803 as sound collecting means capable of collecting sound when the contact member 802 and the metal piece m are brought into contact with each other. On the basis of the sound collected by a sound collecting microphone 803, the presence or absence of the metal piece m is detected.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present invention relates to a sheet conveying device, an automatic document conveying device, an image reading device, and an image forming device.

Background Art

[0002] Conventionally, there has been known a sheet conveying device including a sheet placement unit for placing a sheet, a sheet conveying means for conveying the sheet placed on the sheet placement unit, and a metal detection means for detecting metal attached to the sheet.

[0003] Patent Document 1 describes a metal detection means having an actuator with a magnet member fixed to its tip and supported swingably, and a sensor for detecting the swing of the actuator as the sheet conveying device. When metal such as a clip or staple pin is attached to the sheet, the actuator swings due to the magnetic force between the metal on the sheet and the magnet member, and the sensor detects the swing to detect that metal is attached to the sheet.

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the configuration of the metal detection means described in Patent Document 1 has a problem of causing an increase in the size and cost of the device.

Means for Solving the Problems

[0005] In order to solve the above-described problems, the present invention provides a sheet conveying device including a sheet placement unit for placing a sheet, a sheet conveying means for conveying the sheet placed on the sheet placement unit, and a metal detection means for detecting metal attached to the sheet, The sheet conveying means has a feeding member for feeding a sheet placed on the sheet placement portion. wherein the metal detection means includes a magnetic force generating means, a contact member that contacts the metal attached to the sheet attracted by the magnetic force generating means, and a sound collecting means capable of collecting the sound when the contact member contacts the metal, and detects the metal based on the sound collected by the sound collecting means The contact member and the magnetic force generating means are provided on a holding member that holds the feeding member. It is characterized by the following.

Advantages of the Invention

[0006] According to the present invention, it is possible to suppress the increase in the size and cost of the device.

Brief Description of the Drawings

[0007]

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Embodiments for Carrying Out the Invention

[0008] Hereinafter, embodiments of applying the present invention to an electrophotographic copying machine (hereinafter simply referred to as a copying machine) will be described. First, the basic configuration of the copying machine according to the embodiment will be described. FIG. 1 is a schematic configuration diagram showing the copying machine according to the embodiment. This copying machine includes an image forming unit 1, a blank paper supply device 40, and a document reading device 50. The document reading device 50 has a scanner 150 fixed on the image forming unit 1 and an ADF 51 which is a document conveyance device supported by the scanner 150.

[0009] The blank paper supply device 40 has two sheet placement parts, namely paper feed cassettes 42, arranged in multiple stages in a paper bank 41. Further, the blank paper supply device 40 also has a delivery roller 43 which is a feeding member for sending out a transfer sheet as a sheet from the paper feed cassette, a separation roller 45 which is a separating member for separating the sent-out transfer sheet and supplying it to a paper feed path 44, and the like. The blank paper supply device 40 also has a plurality of conveyance rollers 47 and the like for conveying the transfer sheet to the paper feed path 37 in the image forming unit 1. The blank paper supply device 40 feeds the transfer sheet in the paper feed cassette into the paper feed path 37 in the image forming unit 1.

[0010] Figure 2 is a partial enlarged configuration diagram showing a part of the internal configuration of the image forming unit. The image forming unit 1 as an image forming means includes an optical writing device 2, four process units 3K, Y, M, C for forming toner images of K, Y, M, C colors, and a transfer unit 24. Further, the image forming unit 1 includes a paper conveyance unit 28, a resist roller pair 33, a fixing device 34, a switchback device 36, a paper feed path 37, and the like. The optical writing device 2 drives a light source such as a laser diode or an LED disposed in the device, and irradiates laser light L toward the four drum-shaped photoreceptors 4K, Y, M, C. By this irradiation, an electrostatic latent image is formed on the surface of the photoreceptors 4K, Y, M, C, and this latent image is developed into a toner image via a predetermined developing process. Note that the subscripts K, Y, M, C attached after the reference numerals indicate specifications for black, yellow, magenta, and cyan.

[0011] The process units 3K, Y, M, C each support a photoreceptor and various devices disposed around it as one unit on a common support, and are detachable from the main body of the image forming unit 1. Taking the process unit 3K for black as an example, in addition to the photoreceptor 4K, it has a developing device 6K for developing the electrostatic latent image formed on the surface thereof into a black toner image. It also has a drum cleaning device 15 for cleaning the transfer residual toner adhering to the surface of the photoreceptor 4K after passing through the primary transfer nip for K, which will be described later. This copying machine has a so-called tandem type configuration in which the four process units 3K, Y, M, C are arranged opposite to each other along the endless moving direction with respect to the intermediate transfer belt 25, which will be described later.

[0012] Figure 3 is a partial enlarged view showing a part of the tandem unit composed of the four process units 3K, Y, M, C. Since the four process units 3K, Y, M, C have substantially the same configuration except for the colors of the toners they use, the subscripts K, Y, M, C attached to each reference numeral are omitted in this figure. As shown in this figure, the process unit 3 has a charging device 5, a developing device 6, a drum cleaning device 15, a discharging lamp 22, and the like around the photoreceptor 4.

[0013] The photoreceptor 4 is a drum-shaped one in which a photosensitive layer is formed by applying an organic photosensitive material having photosensitivity to a base tube such as aluminum. However, an endless belt-shaped one may also be used.

[0014] The developing device 6 is adapted to develop a latent image using a two-component developer containing a magnetic carrier and a non-magnetic toner. The developing device 6 has a stirring unit 7 that conveys the two-component developer accommodated therein while stirring and supplies it to the developing sleeve 12, and a developing unit 11 for transferring the toner in the two-component developer carried on the developing sleeve 12 to the photoreceptor 4.

[0015] The stirring unit 7 is provided at a position lower than the developing unit 11, and has two conveying screws 8 arranged in parallel with each other, a partition plate provided between these screws, a toner concentration sensor 10 provided on the bottom surface of the developing case 9, and the like.

[0016] The developing unit 11 has a developing sleeve 12 facing the photoreceptor 4 through an opening of the developing case 9, a magnet roller 13 rotatably provided inside thereof, a doctor blade 14 approaching the tip of the developing sleeve 12, and the like. The developing sleeve 12 is a non-magnetic rotatable cylindrical shape. The magnet roller 13 has a plurality of magnetic poles arranged in sequence from the position facing the doctor blade 14 in the rotational direction of the sleeve. These magnetic poles apply a magnetic force to the two-component developer on the sleeve surface at a predetermined position in the rotational direction. Thereby, 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 along the magnetic field lines is formed on the sleeve surface.

[0017] As the magnetic brush passes through the position facing the doctor blade 14 with the rotation of the developing sleeve 12, it is regulated to an appropriate layer thickness and then conveyed to the developing area facing the photoreceptor 4. Then, due to the potential difference between the developing bias applied to the developing sleeve 12 and the electrostatic latent image on the photoreceptor 4, the toner of the magnetic brush is transferred onto the electrostatic latent image, contributing to development. Further, as the developing sleeve 12 rotates, the magnetic brush returns to the developing unit 11 again. After being detached from the sleeve surface under the influence of the repulsive magnetic field formed between the magnetic poles of the magnet roller 13, it is returned to the stirring unit 7. In the stirring unit 7, an appropriate amount of toner is replenished to the two-component developer based on the detection result by the toner concentration sensor 10. Note that, as the developing device 6, instead of using a two-component developer, one may adopt a device that uses a one-component developer that does not contain a magnetic carrier.

[0018] The drum cleaning device 15 presses a cleaning blade 16 made of polyurethane rubber against the photoreceptor 4, but other methods may also be used. For the purpose of enhancing cleaning performance, the drum cleaning device 15 is provided with a contact conductive fiber brush 17 whose outer peripheral surface is in contact with the photoreceptor 4 and is rotatable in the direction of the arrow in the figure. This fiber brush 17 also serves to scrape the lubricant from the solid lubricant into fine powder and apply it to the surface of the photoreceptor 4.

[0019] A metal electric field roller 18 to which a bias is applied to the fiber brush 17 is provided rotatably 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 fiber brush 17 is displaced to the electric field roller 18 to which a bias is applied while rotating in a counter direction in contact with the fiber brush 17. Then, the toner is scraped off from the electric field roller 18 by the scraper 19 and then falls onto the recovery screw 20. The recovery screw 20 conveys the recovered toner toward the end of the drum cleaning device 15 in a direction perpendicular to the drawing plane and delivers it to an external recycling conveyance device 21. The recycling conveyance device 21 sends the delivered toner to the developing device 6 for recycling.

[0020] The charge-removing lamp 22 removes the charge from the photoreceptor 4 by light irradiation. After the surface of the charged-removed photoreceptor 4 is uniformly charged by the charging device 23, the light writing process is performed by the light writing device 2. As the charging device 23, a device that rotates while bringing a charging roller to which a charging bias is applied into contact with the photoreceptor 4 is used. A scorotron charger or the like that performs the charging process in a non-contact manner with respect to the photoreceptor 4 may be used.

[0021] In FIG. 2 shown above, K, Y, M, C toner images are formed on the photoreceptors 4K, Y, M, C of the four process units 3K, Y, M, C by the processes described so far.

[0022] Below the four process units 3K, Y, M, C, a transfer unit 24 is disposed. This transfer unit 24 moves the intermediate transfer belt 25 stretched by a plurality of rollers in an endless manner in the clockwise direction in the figure while bringing it into contact with the photoreceptors 4K, Y, M, C. As a result, a primary transfer nip for K, Y, M, C where the photoreceptors 4K, Y, M, C and the intermediate transfer belt 25 are in contact is formed. In the vicinity of the primary transfer nip for K, Y, M, C, the primary transfer rollers 26K, Y, M, C disposed inside the belt loop press the intermediate transfer belt 25 toward the photoreceptors 4K, Y, M, C. A primary transfer bias is applied to each of these primary transfer rollers 26K, Y, M, C by a power source. As a result, a primary transfer electric field for electrostatically moving the toner image on the photoreceptors 4K, Y, M, C toward the intermediate transfer belt 25 is formed at the primary transfer nip for K, Y, M, C. On the front surface of the intermediate transfer belt 25 that sequentially passes through the primary transfer nip for K, Y, M, C along with the endless movement in the clockwise direction in the figure, the toner images are sequentially superposed and primarily transferred at each primary transfer nip. By this superposed primary transfer, a four-color superposed toner image (hereinafter referred to as a four-color toner image) is formed on the front surface of the intermediate transfer belt 25.

[0023] Below the middle of the transfer unit 24 in the figure, a paper conveyance unit 28 is provided that passes an endless paper conveyance belt 29 between a drive roller 30 and a secondary transfer roller 31 and moves it endlessly. An intermediate transfer belt 25 and a paper conveyance belt 29 are sandwiched between its own secondary transfer roller 31 and a lower tension roller 27 of the transfer unit 24. As a result, a secondary transfer nip is formed where the front surface of the intermediate transfer belt 25 and the front surface of the paper conveyance belt 29 are in contact. A secondary transfer bias is applied to the secondary transfer roller 31 by a power source. On the other hand, the lower tension roller 27 of the transfer unit 24 is grounded. As a result, a secondary transfer electric field is formed in the secondary transfer nip.

[0024] On the right side in the figure of this secondary transfer nip, a registration roller pair 33 is arranged, and the transfer paper sandwiched between the rollers is sent to the secondary transfer nip at a timing that can synchronize it with the four-color toner image on the intermediate transfer belt 25. Inside the secondary transfer nip, the four-color toner image on the intermediate transfer belt 25 is batch-wise secondarily transferred to the transfer paper under the influence of the secondary transfer electric field and nip pressure, and together with the white color of the transfer paper, it becomes a full-color image. The transfer paper that has passed through the secondary transfer nip separates 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.

[0025] On the surface of the intermediate transfer belt 25 that has passed through the secondary transfer nip, residual transfer toner that was not transferred to the transfer paper at the secondary transfer nip adheres. This residual transfer toner is scraped off and removed by a belt cleaning device that contacts the intermediate transfer belt 25.

[0026] The transfer paper conveyed to the fixing device 34 has the full-color image fixed by pressure and heating inside the fixing device 34, and after being sent from the fixing device 34 to the paper discharge roller pair 35, it is discharged outside the machine.

[0027] In the previously shown FIG. 1, a switchback device 36 is disposed under the paper conveyance unit 28 and the fixing device 34. As a result, the transfer paper that has completed the image fixing process for one side has its path switched to the transfer paper inverter side by a switching claw, where it is inverted and then enters the secondary transfer nip again. Then, after the secondary transfer process and the fixing process of the image are performed on the other side as well, it is discharged onto the discharge tray.

[0028] The scanner 150 fixed above the image forming unit 1 has a first surface fixed reading unit 151 as the first surface reading means and a moving reading unit 152 as the first surface reading means.

[0029] The moving reading unit 152 as the first surface reading means is disposed directly below the second contact glass fixed to the upper wall of the casing of the scanner 150 so as to contact the original MS, and an optical system including a light source, a reflection mirror, etc. can be moved in the left - right direction in the drawing. In the process of moving the optical system from the left side to the right side in the drawing, the moving reading unit 152 reflects the light emitted from the light source by the original placed on the second contact glass, then passes through a plurality of reflection mirrors, and is received by the image reading sensor 153 fixed to the scanner main body.

[0030] The first surface fixed reading unit 151 as the first surface reading means is disposed directly below the first contact glass fixed to the upper wall of the casing of the scanner 150 so as to contact the original MS. Then, when the original MS conveyed by the ADF 51 described later passes over the first contact glass, while sequentially reflecting the light emitted from the light source by the original surface, it passes through a plurality of reflection mirrors and is received by the image reading sensor. Thereby, the first surface of the original MS is scanned without moving the optical system including the light source, the reflection mirror, etc.

[0031] Further, the scanner 150 also has a close - contact type image sensor for reading the second surface of the original MS. This close - contact type image sensor will be described later.

[0032] The ADF 51 disposed on the scanner 150 holds a document placement table 53 for placing the document MS before reading, a conveyance unit for conveying the document MS, a document stacking table 55 for stacking the document MS after reading, etc. on the main body cover 52. As shown in FIG. 4, the ADF 51 is supported by a hinge 159 fixed to the scanner 150 so as to be swingable in the vertical direction. The ADF 51 makes a movement like an opening / closing door by its swing, and exposes the first contact glass 154 and the second contact glass 155 on the upper surface of the scanner 150 in the opened state. In the case of a single-bound document such as a book with one corner of the document bundle stapled, since the documents cannot be separated one by one, the conveyance by the ADF 51 cannot be performed. Therefore, in the case of a single-bound document, after opening the ADF 51 as shown in FIG. 4, place the single-bound document with the page to be read laid out face down on the second contact glass 155, and then close the ADF 51. Then, the image of that page is read by the moving reading unit 152 shown in FIG. 1 of the scanner 150.

[0033] On the other hand, in the case of a document bundle in which a plurality of independent documents MS are simply stacked on top of each other, while automatically conveying the documents MS one by one by the ADF 51, they can be sequentially read by the first surface fixed reading unit 151 in the scanner 150 or the close-contact type image sensor in the ADF 51. In this case, after setting the document bundle on the document placement table 53, the user presses the copy start button. Then, the ADF 51 feeds the document MS of the document bundle placed on the document placement table 53 in order from the top, and conveys it toward the document stacking table 55 while inverting it. During this conveyance process, the document MS is inverted and immediately passes directly above the first surface fixed reading unit 151 of the scanner 150. At this time, the image of the first surface of the document MS is read by the first surface fixed reading unit 151 of the scanner 150.

[0034] FIG. 5 is an enlarged configuration diagram showing the main configuration of the ADF51 together with the upper part of the scanner 150. FIG. 6 is a block diagram showing a part of the electric circuit of the ADF51 and the scanner 150. The ADF51 includes a document set unit A, a separation and conveyance unit B, a registration unit C, a turn unit D, a first reading and conveyance unit E, a second reading and conveyance unit F, a paper discharge unit G, a stack unit H, and the like.

[0035] As shown in FIG. 6, the ADF51 has a controller 904 composed of an ASIC (Application Specific Integrated Circuit) or the like, and various devices and sensors can be controlled thereby. A registration sensor 65, a document set sensor 63, a paper discharge sensor 61, a butting sensor 72, a document width sensor 73, a reading entrance sensor 67, length sensors 57 and 58, and the like are connected to the controller 904. Further, a paper feed motor 191, a conveyance motor 192, a pickup motor 193, a paper discharge clutch 194, and the like are also connected. Also, a sound collecting microphone 803 as sound collecting means, an electromagnet 801 as magnetic force generating means, and the like are connected.

[0036] The electromagnet 801 attracts a metal piece such as a staple pin or a clip attached to the document to a contact member 802 (see FIG. 7) described later and brings it into contact with the contact member 802. The sound collecting microphone 803 captures the sound when a metal piece such as a staple pin or a clip attached to the document hits the contact member 802.

[0037] The scanner 150 has a reading control unit 903 composed of a CPU (Central Processing Unit), a RAM (Random Access Memory), and the like. Thereby, various devices and sensors inside the scanner 150 can be controlled. The reading control unit 903 is connected to the controller 904 of the ADF51 via an I / F, and the reading control unit 903 can also indirectly control various devices and sensors in the ADF51 via the controller 904.

[0038] In FIG. 5, the original document set unit A has an original document placement table 53 or the like on which a bundle of original documents MS in the form of sheets is set. The separation and conveyance unit B separates and feeds the original documents MS one by one from the set bundle of original documents MS. The registration unit C temporarily abuts against the fed original document MS to align the original document MS and then sends it out. The turning unit D has a curved conveyance unit that curves in a C shape, and in this curved conveyance unit, the original document MS is turned over while being folded back and its top and bottom are reversed. The first reading conveyance unit E conveys the original document MS on the first contact glass 154 and causes the first surface fixed reading unit 151 disposed inside the scanner below the first contact glass 154 to read the first surface of the original document MS. The second reading conveyance unit F conveys the original document MS under the close-contact type image sensor 95 and causes the close-contact type image sensor 95 to read the second surface of the original document MS. The paper discharge unit G discharges the original document MS with both-sided images read toward the stack unit H. The stack unit H stacks the original document MS on the original document stack table 55.

[0039] The original document MS has its leading end placed on the movable original document table 54 that can swing in the directions of arrows a and b in the figure according to the thickness of the bundle of original documents MS, and is set in a state where the rear end side of the original document is placed on the original document placement table 53. At this time, on the original document placement table 53, one end in its width direction (the direction perpendicular to the drawing surface) abuts against the setting reference portion 56a (see FIG. 7), and the other end abuts against the side fence 56b (see FIG. 7), so that the position in the width direction is adjusted. The original document MS set in this way pushes up the lever member 62 disposed swingably above the movable original document table 54. Then, accordingly, the original document set sensor 63 detects the setting of the original document MS and transmits a detection signal to the controller 904. And this detection signal is sent from the controller 904 to the reading control unit 903 via the I / F.

[0040] On the original document placement table 53, a first length sensor 57 and a second length sensor 58 are held, which are a reflection type photosensor or an actuator - type sensor for detecting the length of the original document MS in the conveyance direction. The length of the original document MS in the conveyance direction is detected by these length sensors.

[0041] Above the bundle of original documents MS placed on the movable original document table 54, a pickup roller 80, which is a feeding member supported by a cam mechanism so as to be movable in the vertical direction (in the directions of arrows c and d in the figure), is disposed. By driving this cam mechanism with a pickup motor 193, it is possible to move the pickup roller 80 vertically. When the movable original document table 54 swings in the direction of arrow a in the figure, the pickup roller 80 comes into contact with the topmost original document MS in the bundle of original documents MS. Further, when the movable original document table 54 ascends, the pickup roller 80 ascends accordingly, and eventually, the ascent of the movable original document table 54 up to the upper limit is detected by a table ascent sensor 59. Thereby, the ascent of the movable original document table 54 stops.

[0042] For the main body operation unit 902 composed of a numeric keypad, a display, etc. provided on the main body of the copying machine, key operations for setting the reading mode indicating whether it is a double - sided reading mode or a single - sided reading mode by the operator, pressing operations of the copy start key, etc. are performed. That is, the main body operation unit 902 functions as a mode information acquisition means for acquiring information on whether it is in the double - sided reading mode or the single - sided reading mode. When the copy start key is pressed, an original document feeding signal is transmitted from the main body control unit 901 to the controller 904 of the ADF51 via the I / F. Then, the pickup roller 80 is rotationally driven by the forward rotation of the paper feeding motor 191 to send out the original document MS on the movable original document table 54 from above the movable original document table 54.

[0043] When setting the duplex reading mode or the simplex reading mode, it is possible to collectively set the duplex or simplex mode for all the originals MS placed on the movable original table 54. It is also possible to individually set the reading mode for each individual original MS, such as setting the first and tenth originals MS to the duplex reading mode while setting the other originals MS to the simplex reading mode.

[0044] The original MS sent out by the pickup roller 80 enters the separation and conveyance unit B and is fed into the separation unit which is the contact position between the paper feed belt 84 and the separation roller 85. This paper feed belt 84 is stretched between the drive roller 82 and the driven roller 83, and is endlessly moved in the clockwise direction in the figure by the rotation of the drive roller 82 accompanying the forward rotation of the paper feed motor 191. The separation roller 85 which is rotationally driven clockwise in the figure by the forward rotation of the paper feed motor 191 abuts on the lower stretched surface of this paper feed belt 84 to form the separation unit. In the separation unit, the surface of the paper feed belt 84 moves in the paper feed direction. In contrast, the separation roller 85 abuts on the paper feed belt 84 with a predetermined pressure, and when directly abutting on the paper feed belt 84 or when only one original MS is sandwiched in the contact portion, it is rotated along with the belt or the original MS. However, when a plurality of original MS are sandwiched in the contact portion, since the rotational force is lower than the torque of the torque limiter, it is rotationally driven clockwise in the figure in the direction opposite to the rotational direction. As a result, a moving force in the direction opposite to the paper feed is applied to the original MS below the topmost one by the separation roller 85, and only the topmost original MS is separated from several originals.

[0045] The original manuscript MS separated into a single sheet by the action of the paper feed belt 84 and the separation roller 85 enters the registration section C. Then, its tip is detected when passing directly below the abutment sensor 72. At this time, the pickup motor 193 rotates, and the pickup roller 80 retracts from the upper surface of the original manuscript. The original manuscript MS is conveyed only by the endless moving force of the paper feed belt 84. And from the timing when the tip of the original manuscript MS is detected by the abutment sensor 72, the endless movement of the paper feed belt 84 continues for a predetermined time. After that, the tip of the original manuscript MS hits the contact portion between the pull-out driven roller 86 and the pull-out drive roller 87 that rotates while being in contact with it. With the tip of the original manuscript MS hitting the contact portion between the two rollers, the rear end side of the original manuscript MS is sent in the paper feed direction, so that the original manuscript MS is bent by a predetermined amount while the tip is positioned at the contact portion. As a result, the skew (tilt) of the original manuscript MS is corrected, and the original manuscript MS assumes a posture along the paper feed direction.

[0046] In addition to the role of correcting the skew of the original manuscript MS, the pull-out drive roller 87 is responsible for conveying the original manuscript MS with corrected skew to the intermediate roller pair 66 on the downstream side in the original manuscript conveyance direction. The drive roller 82 that stretches the pickup roller 80 and the paper feed belt 84, the pull-out drive roller 87, and the drive roller of the intermediate roller pair are connected to the paper feed motor 191 via a one-way clutch. The one-way clutch connected to the pull-out drive roller 87 and the drive roller of the intermediate roller pair transmits the driving force when the paper feed motor 191 rotates in the reverse direction, and the one-way clutch connected to the drive roller 82 transmits the driving force when the paper feed motor 191 rotates in the forward direction. Therefore, when the paper feed motor 191 rotates in the reverse direction, the pull-out drive roller 87 and the drive roller of the intermediate roller pair 66 start to rotate, and the endless movement of the paper feed belt 84 stops. Also, at this time, the rotation of the pickup roller 80 is stopped.

[0047] The original manuscript MS sent out from the pull-out drive roller 87 passes directly below the manuscript width sensor 73. The manuscript width sensor 73 has a plurality of paper detection parts composed of a reflection type photosensor or the like, and these paper detection parts are arranged in the manuscript width direction (the direction perpendicular to the drawing surface). Based on which paper detection part detects the original manuscript MS, the size in the width direction of the original manuscript MS is detected. Also, the length of the original manuscript MS in the conveyance direction is detected based on the timing from when the leading end of the original manuscript MS is detected by the abutment sensor 72 until the trailing end of the original manuscript MS is no longer detected by the abutment sensor 72.

[0048] The leading end of the original manuscript MS whose size in the width direction has been detected by the manuscript width sensor 73 enters the turning part D and is sandwiched between the contact parts between the rollers of the intermediate roller pair 66. The conveyance speed of the original manuscript MS by this intermediate roller pair 66 is set higher than the conveyance speed of the original manuscript MS in the first reading conveyance part E described later. Thereby, the time until the original manuscript MS is fed into the first reading conveyance part E is shortened.

[0049] The leading end of the original manuscript MS conveyed in the turning part D passes through the position facing the reading entrance sensor 67. When the leading end of the original manuscript MS is detected by the reading entrance sensor 67 as a result, the conveyance speed of the original manuscript by the intermediate roller pair 66 is decelerated until the leading end is conveyed to the position of the reading entrance roller pair (the pair of 89 and 90) on the downstream side in the conveyance direction. Also, with the start of the rotational drive of the conveyance motor 192, one roller in the reading entrance roller pair (89, 90), one roller in the reading exit roller pair 92, and one roller in the second reading exit roller pair 93 start rotational drive respectively.

[0050] In the turning section D, while the original manuscript MS is being conveyed along the curved conveyance path between the intermediate roller pair 66 and the reading entrance roller pair (89, 90), the top and bottom surfaces are reversed and the conveyance direction is folded back. Then, the leading edge of the original manuscript MS that has passed through the nip between the rollers of the reading entrance roller pair (89, 90) passes directly below the registration sensor 65. When the leading edge of the original manuscript MS is detected by the registration sensor 65 at this time, the conveyance speed of the original manuscript MS is decelerated while covering a predetermined conveyance distance, and the conveyance of the original manuscript MS is temporarily stopped in front of the first reading conveyance section E. Also, a stop signal is transmitted to the reading control unit 903 via the I / F.

[0051] When the reading control unit 903 that has received the stop signal transmits a reading start signal, under the control of the controller 904, the rotation of the conveyance motor 192 is restarted until the leading edge of the original manuscript MS reaches within the first reading conveyance section E, and the conveyance speed of the original manuscript MS is accelerated to a predetermined conveyance speed. Then, at the timing when the leading edge of the original manuscript MS reaches the reading position by the first surface fixed reading unit 151, a gate signal indicating the effective image area in the sub-scanning direction of the first surface of the original manuscript MS is transmitted from the controller 904 to the reading control unit 903. This transmission continues until the trailing edge of the original manuscript MS exits the reading position by the first surface fixed reading unit 151, and the first surface of the original manuscript MS is read by the first surface fixed reading unit 151. Note that the timing when the leading edge of the original manuscript MS reaches the reading position by the first surface fixed reading unit 151 is calculated based on the pulse count of the conveyance motor 192.

[0052] The original document MS that has passed through the first reading and conveying unit E is detected by a paper discharge sensor 61 after passing through a reading exit roller pair 92 described later. When the single-sided reading mode is set, it is not necessary to read the second side of the original document MS by a contact image sensor 95 described later. Therefore, when the leading edge of the original document MS is detected by the paper discharge sensor 61, the driving force of a conveyance motor 192 is connected to a paper discharge roller pair 94 by a paper discharge clutch 194, and the lower paper discharge roller in the paper discharge roller pair 94 in the figure is rotationally driven in the clockwise direction in the figure. Also, based on the pulse count of the conveyance motor 192 after the leading edge of the original document MS is detected by the paper discharge sensor 61, the timing at which the trailing edge of the original document MS exits the nip of the paper discharge roller pair 94 is calculated. Then, based on this calculation result, the paper discharge clutch 194 cuts off the driving force of the conveyance motor 192 and stops the paper discharge roller pair 94.

[0053] On the other hand, when the double-sided reading mode is set, after the leading edge of the original document MS is detected by the paper discharge sensor 61, the timing until it reaches the contact image sensor 95 is calculated based on the pulse count of the conveyance motor 192. Then, at that timing, a gate signal indicating the effective image area in the sub-scanning direction on the second side of the original document MS is transmitted from a controller 904 to a reading control unit 903. This transmission continues until the trailing edge of the original document MS exits the reading position by the contact image sensor 95, and the second side of the original document MS is read by the contact image sensor 95.

[0054] The contact image sensor 95 (CIS) as the second surface reading means has a coating process applied to its reading surface for the purpose of preventing vertical streaks in reading caused by paste-like foreign matter adhering to the reading surface when it adheres to the original document MS. At a position facing the contact image sensor 95, a second reading roller 96 is provided as a document support means for supporting the original document MS from the non-reading surface side (first surface side). This second reading roller 96 prevents the original document MS from floating at the reading position by the contact image sensor 95 and also functions as a reference white part for acquiring shading data in the contact image sensor 95. In this copying machine, the second reading roller 96 is used as the document support means for supporting the original document at a position facing the contact image sensor 95, but a guide plate-like one may also be used.

[0055] Next, the characteristic parts of this embodiment will be described. FIG. 7 is an explanatory diagram regarding the arrangement of the sound collecting microphone 803, the electromagnet 801, and the contact member 802. (a) is a schematic plan view, and (b) is a schematic side view.

[0056] When a user carelessly sets an original document MS with a staple pin or a clip, which is a metal piece, attached to the original document placing table 53. When a metal piece m such as a staple pin is attached to the rear end side of the original document, when the original document MS is set on the original document placing table 53, since the metal piece m is exposed, it is easy to notice the presence of the metal piece m before starting the conveyance of the original document. However, as shown in FIG. 7(a), when the original document MS is set on the original document placing table 53, the front end side of the original document is covered by the paper feed cover 98. As a result, when a metal piece m is attached to the front end of the original document MS, there is a high possibility that the conveyance of the original document MS will be started without noticing the metal piece m.

[0057] When transporting a manuscript MS with a metal piece such as a staple or a clip attached, there is a risk that members such as a transport roller may be damaged by the metal piece. Also, when the tip of a bundle of multiple manuscripts MS stapled together by a metal piece such as a staple or a clip enters the separation unit BN, the topmost manuscript in the bundle of manuscripts is continuously transported by the paper feed belt 84. However, for the second and subsequent manuscripts, a transport force to return them is applied by the separation roller 85. As a result, a large stress is applied to the portion stapled by the metal piece, and there is a risk of breakage, folding, or wrinkles occurring in the manuscript, damaging the manuscript. Therefore, in the present embodiment, a metal detection means for detecting the metal piece m attached to the manuscript is provided, and when the metal detection means detects the metal piece m, the transport of the manuscript is stopped.

[0058] The metal detection means for detecting the metal piece m such as a staple or a clip attached to the manuscript includes a contact member 802, an electromagnet 801 as a magnetic force generating means, and a sound collecting microphone 803 as a sound collecting means. The contact member 802 is disposed between the pickup roller 80 and the separation unit BN. The electromagnet 801 is disposed directly above the contact member 802.

[0059] In the present embodiment, a holder 80a that holds the pickup roller 80 in a manner that allows it to be brought into and out of contact with the manuscript placed on the movable manuscript table 54 is disposed approximately at the center in the width direction. The contact member 802 and the electromagnet 801 are disposed on both sides in the width direction with the holder 80a interposed therebetween.

[0060] The contact member 802 may be made of a material that emits a different sound from the operating sound when the metal piece m of the manuscript MS hits the contact member 802 and that allows the magnetic force of the electromagnet 801 to reach the manuscript on the transport path. In particular, a glass material or the like that produces a large collision sound when the metal piece m collides and has a high acoustic effect is suitable.

[0061] The sound collecting microphone 803 is attached to the paper feed cover 98 and is disposed upstream of the pickup roller 80 with respect to the conveyance of the document. The sound collecting microphone 803 may be disposed at any position as long as it can collect the collision sound when the metal piece of the document MS collides with the contact member 802, and may be disposed in a dead space of the apparatus or the like. Thus, in the present embodiment, since the sound collecting microphone 803 can be disposed in the dead space of the apparatus, a situation where the apparatus is expanded for the arrangement of the sound collecting microphone 803 can be avoided. As a result, an increase in the size of the apparatus can be suppressed.

[0062] Note that reference numeral 56 in Fig. 7(a) is a setting reference portion when setting the document MS, and reference numeral 55 is a side fence. One end of the document MS set on the document placing table 53 abuts against the setting reference portion 56a at one end in the width direction, and the other end abuts against the side fence 56b, whereby the position in the width direction is regulated. That is, in the present embodiment, the side fence 56b and the setting reference portion 56a function as regulating members.

[0063] Fig. 8 is a diagram for explaining the detection of the metal piece m attached to the document MS. When feeding the document MS on the document placing table 53 by the pickup roller 80, the controller 904 energizes the electromagnet 801 to generate a magnetic force in the region where the contact member 802 in the document conveyance path faces. When the metal piece m attached to the document MS enters the region where the contact member 802 faces, the metal piece m is attracted to the contact member 802 by the magnetic force of the electromagnet 801. Due to the magnetic force that attracts the metal piece m to the contact member 802, the periphery of the metal piece m of the document MS floats, and the metal piece m collides with the contact member 802 (see Fig. 8(b)). When this metal piece m collides with the contact member 802, an abnormal sound (collision sound) is generated. As a result, the abnormal sound (collision sound) is mixed into the operation sound collected by the sound collecting microphone 803, resulting in a characteristic operation sound. Thereby, it is possible to distinguish from the operation sound during normal conveyance, and it is possible to detect that the metal piece m is attached to the document from the operation sound collected by the sound collecting microphone 803.

[0064] In addition, in the present embodiment, the contact member 802 is disposed upstream of the separation unit BN in the document conveyance direction, and before the leading edge of the document MS reaches the separation unit BN, the presence or absence of the metal piece m is determined so that the conveyance of the document MS can be stopped. Therefore, it is possible to suppress the leading edges of a plurality of documents bound by the metal piece m from entering the separation unit BN, and it is possible to suppress the occurrence of tearing, folding, wrinkles, etc. of the document MS, and it is possible to suppress damage to the document MS.

[0065] In addition, it is preferable to perform ON / OFF control of energization to the electromagnet 801 and repeatedly perform ON / OFF control of the magnetic force so that the metal piece m contacts the contact member 802 a plurality of times. In this way, by contacting the metal piece m with the contact member 802 a plurality of times, it is possible to collect more characteristic operation sounds. As a result, as will be described later, in machine learning, it becomes possible to discriminate normal conveyance and abnormal conveyance in which the metal piece m contacts the contact member 802 with less learning data.

[0066] In addition, since a predetermined time is required from when the metal piece m collides with the contact member 802 until it is determined as abnormal conveyance from the operation sound and the paper feeding operation stops, conveyance continues for a predetermined time even after the metal piece m collides with the contact member 802. As a result, when the energization to the electromagnet 801 is always in the ON state, the vicinity of the document MS with the metal piece m where the metal piece m is in contact with the contact member 802 due to the magnetic force will not be conveyed. As a result, there is a risk of wrinkles and folds occurring in the document. On the other hand, when repeatedly performing ON / OFF control of the magnetic force, since the document is conveyed when the magnetic force is OFF, it is possible to suppress the occurrence of wrinkles and folds in the document, such as the document being bent in the document conveyance path, until the operation sound is analyzed and determined as abnormal conveyance and the paper feeding operation stops. Note that when it is difficult to perform ON / OFF control of the magnetic force a plurality of times while the metal piece m passes through the facing area with the contact member 802, the magnetic force is always generated.

[0067] In addition, in the present embodiment, the contact member 802 and the electromagnet 801 are divided into a plurality of parts so as not to interfere with the holder 80a disposed substantially at the center in the width direction. However, in the present embodiment, even if the contact member 802 and the electromagnet 801 are divided into a plurality of parts due to the arrangement of the members of the apparatus, the presence or absence of the metal piece m can be detected by one sound collecting microphone 803 for the end portion on the set reference portion 56a side of the document and the end portion on the side fence 56b side. Thereby, an increase in the number of parts can be suppressed, and an increase in the cost of the apparatus can be suppressed.

[0068] FIG. 9 is a flowchart showing the metal piece discrimination process performed by the controller 904. As described above, when a document feeding signal is transmitted from the main body control unit 901 to the controller 904, the paper feeding / separating operation is started (S1), and at the same time, the sound collecting microphone 803 collects the paper feeding / separating operation sound (S2). Further, the electromagnet 801 is energized to generate a magnetic force in the region where the contact member 802 of the document conveyance path faces.

[0069] The controller 904 sequentially cuts out the collected operation sound data into frames of a predetermined length, and calculates the mel frequency cepstrum coefficient which is a feature amount of the sound (S3). When the ON / OFF control of the magnetic force is repeatedly performed so that the metal piece m hits the contact member 802 a plurality of times, it is preferable that the cutting out of the operation sound data is longer than the time from when the metal piece m enters the facing region facing the contact member 802 until it exits this facing region. Thereby, the collision sound of the metal piece m hitting the contact member 802 a plurality of times can be recorded in the cut-out operation sound data.

[0070] The mel frequency cepstrum coefficient is a feature amount obtained by weighting the spectral envelope of the voice (frequency characteristics derived from the vocal tract component) with the mel frequency in consideration of the human frequency perception characteristics, and is often used as a feature amount for voice recognition.

[0071] The above-mentioned "Mel frequency" is a frequency that is converted considering the characteristic of human pitch perception that sounds closer to the lower limit of the audible range sound higher and those closer to the upper limit sound lower to humans. The "cepstrum" is obtained by performing a Fourier transform on an audio signal (waveform data) to convert it into a frequency spectrum, then taking the logarithm of that, and performing an inverse Fourier transform to return it to the time domain. The "cepstrum" is also called the "inverse Fourier transform of the logarithm of the spectrum" (the spectrum of the spectrum), and it separates the fine structure of the spectrum (subtle and minute changes) from the gradual changes in the spectrum (spectral envelope).

[0072] Mel-frequency cepstral coefficients are generally obtained as follows. That is, after converting the amplitude spectrum obtained from audio data to the Mel frequency, triangular band-pass filters are arranged while overlapping them to form a Mel filter bank as a filter bank, and the Mel frequency spectrum is obtained by compressing it to 20 dimensions. The obtained Mel frequency spectrum is subjected to a discrete cosine transform to obtain the Mel-frequency cepstrum that separates the fine structure of the spectrum of the high-order components (subtle and minute changes) from the spectral envelope of the low-order components. By extracting the spectral envelope of the low-order components of this Mel-frequency cepstrum, Mel-frequency cepstral coefficients are obtained.

[0073] Mel-frequency cepstral coefficients are generally those that extract a spectral envelope consisting of 12 dimensions (12 pieces of data) as a feature quantity, and can represent the characteristics of audio data with a small amount of data. As a result, the computational load on the controller 904 can be reduced. Note that the number of dimensions to be extracted from the Mel-frequency cepstrum is not limited to 12 dimensions and may be determined as appropriate.

[0074] The Mel-frequency cepstral coefficients are obtained by extracting the spectral envelope of speech, which is the frequency characteristic derived from the vocal tract component. However, the spectral envelopes of the operating sounds during normal conveyance during the paper feeding / separation operation and the operating sound when the metal piece m of the document collides with the contact member 802 are different from each other. Therefore, it is possible to determine whether or not a collision of the metal piece m of the document with the contact member 802 has occurred based on the Mel-frequency cepstral coefficients.

[0075] Note that, in the present embodiment, the Mel-frequency cepstral coefficients are used as a feature quantity that quantitatively represents the characteristics of the operating sound used for determining the collision of the metal piece m of the document with the contact member 802, but it is not limited thereto. For example, known sound feature quantities such as linear prediction coefficients may be used as the feature quantity of the operating sound used for determining the collision of the metal piece m with the contact member 802.

[0076] The calculated Mel-frequency cepstral coefficients are given to a classifier using a support vector machine, which is one of the pattern recognition models using supervised learning, and the operating state is determined (S4).

[0077] The support vector machine linearly separates and classifies multi-dimensional data into a plurality of classes. The support vector machine classifies the Mel-frequency cepstral coefficients, which are the feature quantities of the operating sound of the paper feeding / separation operation collected by the sound collection microphone 803, into either normal conveyance in which no metal piece is detected or abnormal conveyance in which a metal piece is detected. That is, the Mel-frequency cepstral coefficients calculated from the operating sound in which the collision sound when the metal piece m of the document collides with the contact member 802 is collected are classified as abnormal conveyance. On the other hand, the Mel-frequency cepstral coefficients calculated from the operating sound in which no collision sound is collected are classified as normal conveyance.

[0078] The support vector machine can have high generalization performance with a small amount of training data and can accurately determine normal conveyance and abnormal conveyance. Note that, in the present embodiment, a support vector machine is used as the classifier, but a classifier using a deep learning method may also be used.

[0079] When the classifier by the support vector machine classifies the given mel-frequency cepstral coefficients as normal conveyance and determines it as normal conveyance (without metal piece m), the above-described manuscript conveyance process is executed. That is, after the paper feeding / separating operation is completed (S5), the paper feeding motor 191 is reversed, and after the pulling-out operation (S6) of sending out the skew-corrected manuscript by the pull-out driving roller 87, a registration process (S7) is performed to temporarily stop the conveyance of the manuscript MS in front of the first reading conveyance unit E. Then, it waits for the reception of the reading start signal from the reading control unit 903 (S8), and after the reception, the conveyance of the manuscript is restarted, and a reading conveyance process is started to sequentially convey the manuscript to the first reading conveyance unit E, the second reading conveyance unit F, and the paper discharge unit G (S9).

[0080] On the other hand, when the mel-frequency cepstral coefficients calculated from the operating sound when there is a metal piece m attached to the manuscript and the metal piece m hits the contact member 802 and abnormal sound is generated are given, the classifier classifies the given mel-frequency cepstral coefficients as abnormal conveyance. When the classifier classifies the mel-frequency cepstral coefficients as abnormal conveyance (with metal piece), the driving of the paper feeding motor 191 is stopped, and the pickup roller 80 is raised by the pickup motor 193 to stop the paper feeding / separating operation (S10). Also, a message such as "Abnormal conveyance of the manuscript has been detected. Please check the manuscript" is displayed on the display unit of the main body operation unit 902 together with an alarm sound to notify the user of the conveyance state (S11).

[0081] When the rear end side of the manuscript is stapled with a metal piece m such as a staple pin, the front end of the manuscript enters the separation unit BN before the metal piece m enters the opposing area with the contact member 802. And there is a possibility that the conveyance may continue until the rear end of the manuscript enters the opposing area with the contact member 802. Thus, if the conveyance continues even after the front end of the manuscript enters the separation unit BN, a large stress is applied to the part stapled with the metal piece m, and there is a risk of breakage, folding, wrinkles, etc., which may damage the manuscript.

[0082] When a plurality of original documents with their rear ends stapled with a metal piece m such as a staple needle enter the separation unit BN, the topmost original document in contact with the paper feed belt 84 continues to be conveyed, but the second and subsequent original documents are stopped by the separation roller 85. Therefore, among the plurality of original documents with their rear ends stapled with a metal piece m such as a staple needle, the second and subsequent original documents stopped by the separation roller 85 become the conveyance resistance of the topmost original document, and slip occurs between the topmost original document and the pickup roller 80.

[0083] Therefore, it is possible to determine whether slip has occurred between the pickup roller 80 and the original document from the operation sound collected by the sound collecting microphone 803, and when it is determined that slip has occurred, the conveyance of the original document may be stopped. Thereby, before the metal piece m such as a staple needle stapled to the rear end side of the original document enters the opposing region with the contact member 802, the conveyance of the original document can be stopped, and it is possible to suppress the occurrence of tearing, folding, etc. at the rear end of the original document stapled with the metal piece m.

[0084] Next, a modification of this embodiment will be described. [Modification 1] FIG. 10 is a schematic diagram showing the configuration of Modification 1. As shown in FIG. 10, in Modification 1, the contact member 802 and the electromagnet 801 are arranged below the original document conveyance path from the pickup roller 80 to the separation unit BN. The contact member 802 is arranged below the guide surface of the original document guide 88, and the electromagnet 801 is arranged below the contact member 802.

[0085] As shown in FIG. 10, since there are no members arranged near the central portion in the sheet width direction on the lower side of the original document conveyance path, it is possible to arrange one contact member 802 and electromagnet 801 that are long in the original document width direction without dividing the contact member 802 and the electromagnet 801 into a plurality. Thereby, the number of parts can be reduced, and the reduction of the assembly man-hours and the like can be achieved. Further, in this Modification 1, it is also possible to detect the metal piece m attached to the center in the original document width direction.

[0086] FIG. 11 is a diagram for explaining the detection of the metal piece m attached to the document in Modification 1. When there is no metal piece m on the document MS, the document fed by the pickup roller 80 is guided by the document guide 88 and moves to the separation unit BN. On the other hand, when there is a metal piece m on the document MS, when the metal piece m of the document MS enters the facing area with the contact member 802, it is attracted to the contact member 802 by the magnetic force of the electromagnet 801. Then, the periphery of the metal piece m of the document bends downward and the metal piece m collides with the contact member 802 (see FIG. 10(b)), and an abnormal sound (collision sound) is generated. Therefore, also in this Modification 1, an abnormal sound (collision sound) is mixed in the operation sound collected by the sound collecting microphone 803, resulting in a characteristic operation sound, and it is detected from the operation sound that the metal piece m is attached to the document.

[0087] [Modification 2] FIG. 12 is a schematic diagram showing the configuration of Modification 2. In Modification 2, the contact member 802 and the electromagnet 801 are provided on the holder 80a that supports and moves up and down the pickup roller 80, and the contact member 802 is disposed to face the leading end of the document placed on the document placement table 53. In the configuration shown in this Modification 2, it is possible to detect whether or not a metal piece m is attached to the document before the start of feeding by the pickup roller 80.

[0088] Among a plurality of documents stapled with a metal piece m such as a staple pin, the topmost document is given a conveying force from the pickup roller 80, but for the other documents, no conveying force is given. Therefore, stress acts at the location of the stapled metal piece m, and folds or wrinkles may occur near the metal piece m, which may damage the document. In Modification 2, since it is possible to detect whether or not a metal piece m is attached to the document before the start of feeding, it is possible to prevent damage to the document.

[0089] FIG. 13 is a diagram for explaining the detection of the metal piece m attached to the document in Modification 2. As shown in Fig. 13(a), when the document is set on the document placement table 53 and reading of the document MS is instructed, the movable document table 54 rises. Then, when the table rising sensor 59 turns ON and the position of the upper surface of the document stack on the document placement table 53 is positioned at the paper feeding position, the rising of the movable document table 54 stops. When the rising of the movable document table 54 stops, power is supplied to the electromagnet 801. When a metal piece m is attached to the leading end of the document MS, as shown in Fig. 13(b), the metal piece m is attracted by the magnetic force, the leading end of the document MS floats, the metal piece m collides with the contact member 802, and a strange noise (collision sound) is generated. As a result, the strange noise (collision sound) is mixed into the operation sound collected by the sound collecting microphone 803, and it is possible to detect that the metal piece m is attached to the document from the operation sound collected by the sound collecting microphone 803.

[0090] In the second modification, the energization of the electromagnet 801 is controlled ON / OFF, the ON / OFF control of the magnetic force is repeatedly performed, and the metal piece m is made to hit the contact member 802 a plurality of times so as to obtain characteristic operation sounds.

[0091] When it is detected that the metal piece m is attached to the document MS, the movable document table 54 is lowered, and a message such as "An abnormality has been detected. Please check the document" is displayed on the display unit of the main body operation unit 902 together with an alarm sound to notify the user. On the other hand, when the operation sound collected by the sound collecting microphone 803 is normal, the pickup roller 80 or the like is driven to start conveying the document.

[0092] Note that it is preferable to continue to supply power to the electromagnet 801 to generate a magnetic force even after the driving of the pickup roller 80 is started, and to continue to detect the metal piece m during document conveyance. Thereby, it is possible to detect also the metal piece m on the upstream side in the conveyance direction from the leading end of the document MS. Then, when the abutment sensor 72 (see Fig. 5) detects the document and raises the pickup roller 80, the power supply to the electromagnet 801 is turned OFF to turn off the magnetic force. For the second and subsequent sheets, when the pickup roller 80 is lowered and the pickup roller 80 comes into contact with the uppermost document MS on the document placement table 53, the electromagnet 801 is energized to detect the metal piece m.

[0093] [Modification Example 3] FIG. 14 is a schematic diagram showing the configuration of Modification Example 3. In Modification Example 3, a contact member 802 and an electromagnet 801 are arranged at the downstream end of the side fence 56b in the document conveyance direction and the downstream end of the setting reference portion 56a in the document conveyance direction.

[0094] Regarding this Modification Example 3 as well, similar to Modification Example 2, it is possible to detect the presence or absence of the metal piece m before document conveyance and prevent damage to the document MS. Further, in this Modification Example 3, even if the length in the width direction of the contact member 802 and the electromagnet 801 is short compared to Modification Example 2, it is possible to detect the metal pieces m at both ends in the width direction of the document MS.

[0095] Further, the contact member 802 and the electromagnet 801 provided on the side fence 56b and the setting reference portion 56a may be lengthened in the conveyance direction within the sound collection range of the sound collection microphone 803. With such a configuration, it is possible to detect the metal pieces m attached near both ends in the width direction of the document over a wide range in the conveyance direction.

[0096] FIG. 15 is a diagram for explaining an example in which the iron core 801b of the electromagnet 801 is used as a contact member. FIG. 15(a) is a diagram showing an example in which the iron core 801b of the electromagnet 801 is used as a contact member in the configuration shown in FIG. 7, FIG. 15(b) is a diagram showing an example in which the iron core 801b of the electromagnet 801 is used as a contact member in the configuration of Modification Example 1. Further, FIG. 15(c) is a diagram showing an example in which the iron core 801b of the electromagnet 801 is used as a contact member in the configuration of Modification Example 2, and FIG. 15(d) is a diagram showing an example in which the iron core 801b of the electromagnet 801 is used as a contact member in the configuration of Modification Example 3.

[0097] As shown in FIGS. 15(a) to 15(d), the electromagnet 801 is composed of an iron core 801b and a coil 801a wound around the iron core 801b. Then, a part of the iron core 801b is arranged in the same manner as the contact member shown in the embodiment and the modification example, and is used as a contact portion 802' against which the metal piece m attached to the manuscript attracted by the magnetic force hits. Since the iron core 801b is a metal member, when the metal piece m attached to the manuscript MS hits it, a characteristic loud collision sound is generated. Therefore, even when the iron core 801b of the electromagnet 801 is used as the contact member, it is possible to well distinguish normal conveyance from abnormal conveyance where the metal piece m collides with the iron core 801b from the operation sound collected by the sound collecting microphone 803, and to accurately detect the metal piece m of the manuscript MS.

[0098] Also, in this embodiment, an electromagnet is used as the magnetic force generating means, but a permanent magnet may be used. By using a permanent magnet, magnetic force can be generated with a simple configuration, and the cost of the device can be reduced compared to the case of using an electromagnet. On the other hand, by using an electromagnet, ON / OFF control of the magnetic force can be performed. As described above, the metal piece m can be made to collide with the contact member 802 a plurality of times, a more characteristic operation sound can be collected, and the metal piece m can be accurately detected.

[0099] Note that even in a configuration using a permanent magnet, by adopting a configuration as shown in FIG. 16, it becomes possible to turn ON / OFF the magnetic force acting on the manuscript. That is, it is a configuration in which a magnetic force shielding member 805 that reciprocates between a shielding position and a retracted position between the permanent magnet 804 and the contact member 802 is provided. When the magnetic shielding member 805 is in the shielding position shown by the dashed line in the figure, the magnetic force of the permanent magnet 804 is shielded by the magnetic shielding member 805, and the magnetic force does not reach the area facing the contact member 802 of the document conveyance path, so that the magnetic force acting on the document can be turned off. On the other hand, when the magnetic shielding member 805 is in the retracted position shown by the solid line in the figure, the magnetic force of the permanent magnet 804 reaches the area facing the contact member 802 of the document conveyance path, and the magnetic force acting on the document can be turned on. Therefore, by reciprocating the magnetic shielding member 805 between the shielding position and the retracted position, ON / OFF control of the magnetic force can be performed.

[0100] In the above description, an example in which the present invention is applied to the ADF 51 as a sheet feeding device has been described, but the present invention can also be applied to the blank paper feeding device 40 as a sheet feeding device. When reusing a transfer sheet, which is a sheet with an image printed on the front side, as a backing sheet, there is a risk of forgetting to remove metal pieces such as staple pins and clips and setting them in the paper feed cassette 42 of the blank paper feeding device 40. As a result, as described above, there is a risk that members such as the conveyance roller may be damaged by the metal piece attached to the transfer sheet. Therefore, also in the blank paper feeding device 40, similarly to the above, the contact member 802 and the electromagnet 801 are arranged between the delivery roller 43 and the separation roller 45 or on the side fence or the like. Then, the sound when the metal piece attached to the transfer sheet attracted by the magnetic force collides with the contact member is collected by the sound collecting microphone 803 to determine the presence or absence of metal. If it is determined that metal is attached, it is regarded as abnormal and the feeding is stopped. Thereby, it is possible to suppress damage to members such as the conveyance roller by the metal piece attached to the transfer sheet.

[0101] What has been described above is an example, and each of the following aspects has a specific effect. (Aspect 1) In a sheet conveying apparatus including a sheet placement unit such as a document placement table 53 for placing a sheet such as a document MS, a sheet conveying means for conveying the sheet placed on the sheet placement unit, and a metal detection means for detecting metal attached to the sheet, the metal detection means includes a magnetic force generating means such as an electromagnet 801, a contact member 802 that contacts a metal such as a metal piece m attached to the sheet attracted by the magnetic force generating means, and a sound collecting means such as a sound collecting microphone 803 capable of collecting the sound when the contact member 802 and the metal come into contact. Based on the sound collected by the sound collecting means, the metal is detected. In the metal detection means described in Patent Document 1, since the actuator swings, it is necessary to provide space inside the apparatus, which may lead to an increase in the size of the apparatus. Further, when the magnetic member is divided into a plurality due to the arrangement of members of the apparatus such as a conveying roller disposed at the center in the sheet width direction, it is necessary to provide an actuator and a sensor corresponding to the magnetic member, which increases the number of parts and may lead to an increase in the cost of the apparatus. On the other hand, in Aspect 1, it is possible to detect the presence or absence of metal without a member that swings, and there is no need to secure space for a member to swing inside the apparatus, thus avoiding an increase in the size of the apparatus. Further, the sound collecting means may be any location that can collect the sound when the metal contacts the contact member, and has a high degree of freedom in arrangement and can be arranged in the dead space of the apparatus. Therefore, a situation where the apparatus is expanded for the arrangement of the sound collecting means can be avoided, and an increase in the size of the apparatus can be suppressed. Also, in Aspect 1, the sound collecting means can collect the sound when the metal contacts the contact member over a wide range. Therefore, even when the magnetic force generating means or the contact member is divided into a plurality due to the arrangement of members of the apparatus, it is possible to collect the sound when the metal of each contact member contacts with one sound collecting means. Thereby, when the magnetic force generating means etc. are divided into a plurality, the number of parts can be reduced compared to the metal detection means of Patent Document 1, and an increase in the cost of the apparatus can be suppressed.

[0102] (Aspect 2) In Mode 1, the sheet conveying means includes a feeding member such as a pickup roller 80 that feeds a sheet placed on a sheet placement portion such as the document placement table 53, and a separating portion BN that separates a plurality of sheets fed by the feeding member into single sheets, and the contact member 802 is disposed upstream of the separating portion BN in the sheet conveying direction. According to this, as described in the embodiment, it is possible to determine whether or not metal is attached to the sheet before the leading edge of the sheet such as the document MS enters the separating portion BN. Thus, when it is detected that metal is attached to the sheet, the conveyance of the sheet can be stopped before the leading edge of the sheet enters the separating portion BN. Thereby, it is possible to suppress the leading edge of a bundle of sheets stapled together by metal from entering the separating portion BN, and it is possible to suppress damage such as tearing or folding occurring to the sheet.

[0103] (Mode 3) In Mode 1, the contact member 802 is disposed so as to face a sheet placed on a sheet placement portion such as the document placement table 53. According to this, as described in Modification 2 and Modification 3, it is possible to detect whether or not metal is attached to the sheet before the start of sheet conveyance of the sheet such as the document MS. Thereby, it is possible to prevent damage such as folding or wrinkling from occurring to the sheet stapled with metal by conveyance.

[0104] (Mode 4) In Mode 3, the sheet conveying means includes a feeding member such as a pickup roller 80 that feeds a sheet placed on a sheet placement portion such as the document placement table 53, and the contact member 802 and a magnetic force generating means such as an electromagnet 801 are provided on a holding member such as a holder 80a that holds the feeding member. According to this, as described in Modification 2, the contact member 802 can be opposed to a sheet placed on a sheet placement portion such as the document placement table 53, and a magnetic force that attracts the contact member to the metal attached to the sheet placed on the sheet placement portion can be applied. Thereby, it is possible to detect whether or not metal is attached to the sheet before the start of sheet conveyance.

[0105] (Aspect 5) In Aspect 3, sheet regulating members such as side fences 56b and set reference portions 56a that regulate the widthwise position of a sheet placed on a sheet placement portion such as the original document placement table 53 are provided, and a contact member 802 and magnetic force generating means such as an electromagnet 801 are provided on the sheet regulating members. According to this, as described in Modification 3, the contact member 802 can be opposed to the sheet placed on the sheet placement portion such as the original document placement table 53, and a magnetic force that attracts the contact member to the metal attached to the sheet placed on the sheet placement portion can be applied. Thereby, it is possible to detect whether or not metal is attached to the sheet before the start of sheet conveyance.

[0106] (Aspect 6) In any of Aspects 3 to 5, the metal detection means performs metal detection before the start of sheet conveyance. According to this, as described in Modification 2 and Modification 3, it is possible to prevent damage such as folding or wrinkles from occurring in the sheet bound with metal by conveyance.

[0107] (Aspect 7) In any of Aspects 1 to 6, the magnetic force generating means is an electromagnet. According to this, as described in the embodiment, ON / OFF control of the magnetic force can be performed by ON / OFF control of energization, and compared with the case of a permanent magnet, ON / OFF control of the magnetic force can be performed with a space-saving configuration. Further, the magnetic force acting can be adjusted by the current flowing through the coil 801a.

[0108] (Aspect 8) In any of Aspects 1 to 6, the magnetic force generating means is a permanent magnet. According to this, as described in the embodiment, compared with the case where an electromagnet is used as the magnetic force generating means, it can be configured at a lower cost. Further, by using a magnetic force shielding member, ON / OFF control of the magnetic force acting on the sheet is also possible, similar to an electromagnet.

[0109] (Aspect 9) In aspect 7 or 8, the metal detection means repeatedly generates a state in which a magnetic force acts on the sheet and a state in which no magnetic force acts to perform metal detection. According to this, as described in the embodiment, a metal such as the metal piece m can be made to collide with the contact member 802 a plurality of times, and a more characteristic operating sound can be collected by a sound collection means such as a sound collection microphone. As a result, in machine learning, it becomes possible to discriminate between the normal operating sound with less learning data and the operating sound when the metal piece m contacts the contact member 802.

[0110] (Aspect 10) In an automatic document feeder such as the ADF51, which includes a document conveyance unit that conveys a document and conveys the document to an image reading unit by the document conveyance unit, as the document conveyance unit, the sheet conveyance device according to any one of aspects 1 to 9 is used. According to this, as described in the embodiment, it is possible to suppress the document conveyance unit from being damaged by the metal of the document, and to suppress an increase in the size and cost of the apparatus.

[0111] (Aspect 11) In an image reading apparatus such as the document reading apparatus 50, which includes an automatic document feeder such as the ADF51 and an image reading means such as a scanner 150 that reads an image on a document conveyed by the automatic document feeder, as the automatic document feeder, the automatic document feeder according to aspect 10 is provided. According to this, an increase in the size and cost of the apparatus can be suppressed.

[0112] (Aspect 12) In an image forming apparatus that includes an image reading apparatus such as the document reading apparatus 50 and an image forming means that forms an image based on the image information read by the image reading apparatus, as the image reading apparatus, the image reading apparatus according to aspect 11 is provided. According to this, an increase in the size and cost of the apparatus can be suppressed.

[0113] (Aspect 13) An image forming apparatus includes a sheet conveyance unit that conveys a sheet such as a transfer sheet, and forms an image on the sheet conveyed by the sheet conveyance unit. The sheet conveyance unit includes a sheet conveyance device according to any one of Aspects 1 to 9. According to this, it is possible to suppress damage to the conveyance member that conveys the sheet by the metal of the sheet, and to suppress an increase in the size and cost of the apparatus.

Explanation of Signs

[0114] 1: Image forming unit 40: Plain paper supply device 41: Paper bank 42: Paper cassette 43: Delivery roller 45: Separation roller 50: Document reading device 51: ADF 53: Document placement table 54: Movable document table 55: Document stack table 56a: Setting reference part 56b: Side fence 80: Pickup roller 80a: Holder 82: Driving roller 83: Driven roller 84: Paper feed belt 85: Separation roller 88: Document guide 98: Paper feed cover 150: Scanner 801: Electromagnet 801a: Coil 801b: Core 802: Contact member 802′: Contact part 803: Sound collecting microphone 804: Permanent magnet 805: Magnetic shielding member 901: Main body control unit 902: Main body operation unit 904: Controller A: Original document set unit B: Separation and conveyance unit BN: Separation unit C: Resist unit D: Turn unit E: First reading and conveyance unit F: Second reading and conveyance unit G: Paper discharge unit H: Stack unit MS: Original document m: Metal piece

Prior art documents

Patent documents

[0115]

Patent Document 1

Claims

1. a sheet placement section for placing a sheet; sheet conveying means for conveying the sheet placed on the sheet placement section; In a sheet conveying apparatus comprising metal detecting means for detecting metal attached to the sheet, the sheet conveying means has a feeding member for feeding the sheet placed on the sheet placement section, the metal detecting means magnetic force generating means; a contact member that contacts the metal attached to the sheet attracted by the magnetic force generating means; a sound collecting means capable of collecting the sound when the contact member and the metal come into contact; detecting the metal based on the sound collected by the sound collecting means; A sheet conveying apparatus, characterized in that the contact member and the magnetic force generating means are provided on a holding member that holds the feeding member.

2. A sheet placement section for placing a sheet; sheet conveying means for conveying the sheet placed on the sheet placement section; In a sheet conveying apparatus comprising metal detecting means for detecting metal attached to the sheet, a sheet regulating member for regulating the widthwise position of the sheet placed on the sheet placement section is provided, the metal detecting means magnetic force generating means; a contact member that contacts the metal attached to the sheet attracted by the magnetic force generating means; a sound collecting means capable of collecting the sound when the contact member and the metal come into contact; detecting the metal based on the sound collected by the sound collecting means; A sheet conveying apparatus, characterized in that the contact member and the magnetic force generating means are provided on the sheet regulating member.

3. A sheet placement section for placing a sheet; sheet conveying means for conveying the sheet placed on the sheet placement section; In a sheet conveying apparatus comprising metal detecting means for detecting metal attached to the sheet, the metal detecting means magnetic force generating means; a contact member that contacts the metal attached to the sheet attracted by the magnetic force generating means; a sound collecting means capable of collecting the sound when the contact member and the metal come into contact; repeatedly generating a state in which a magnetic force acts on the sheet and a state in which no magnetic force acts; A sheet conveying apparatus, characterized in that the metal is detected based on the sound collected by the sound collecting means.

4. In the sheet conveying apparatus according to any one of Claims 1 to 3, the sheet conveying means has a feeding member for feeding the sheet placed on the sheet placement section and a separating section for separating a plurality of sheets fed by the feeding member into single sheets. A sheet conveying device, characterized in that the contact member is arranged upstream of the separation part in the sheet conveying direction.

5. In the sheet conveying device according to any one of Claims 1 to 4, A sheet conveying device, characterized in that the contact member is arranged so as to face the sheet placed on the sheet placement part.

6. In the sheet conveying device according to Claim 5, The metal detection means performs metal detection before the start of sheet conveyance. A sheet conveying device characterized by this.

7. In the sheet conveying device according to any one of Claims 1 to 6, A sheet conveying device, characterized in that the magnetic force generating means is an electromagnet.

8. In the sheet conveying device according to any one of Claims 1 to 6, A sheet conveying device, characterized in that the magnetic force generating means is a permanent magnet.

9. An automatic document feeder having a document conveyance unit for conveying a document, In the automatic document feeder that conveys a document to an image reading unit by the document conveyance unit, An automatic document feeder, characterized in that the sheet conveying device according to any one of Claims 1 to 8 is used as the document conveyance unit.

10. An image reading device including an automatic document feeder and image reading means for reading an image on a document conveyed by the automatic document feeder, An image reading device, characterized in that the automatic document feeder according to Claim 9 is provided as the automatic document feeder.

11. An image forming device including an image reading device and image forming means for forming an image based on the image information read by the image reading device, An image forming device, characterized in that the image reading device according to Claim 10 is provided as the image reading device.

12. An image forming device including a sheet conveying unit for conveying a sheet, In the image forming device that forms an image on the sheet conveyed by the sheet conveying unit, An image forming device, characterized in that the sheet conveying device according to any one of Claims 1 to 8 is provided as the sheet conveying unit.

Images