JP2024031808A - Sheet transport device, automatic document transport device and image formation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet transport device, an automatic document transport device, and an image formation device capable of suppressing erroneous determination of transport failure.

SOLUTION: The ROM of the controller stores indicator data (inverse matrix R-1 and threshold value Th) when there is no preceding document being transported and indicator data (inverse matrix R-1 and threshold value Th) when there is a preceding document being transported. The controller knows the number of documents being transported as a transport condition, and if there are two or more documents being transported, the controller selects the indicator data for the case where there is a preceding document being transported, and if there is one document being transported, the controller selects the indicator data for the case where there is no preceding document being transported (S5-S7). Then, using the selected indicator data (inverse matrix R-1 and threshold value Th), a transport failure determination is made as to whether or not a transport failure occurs (S8).

SELECTED DRAWING: Figure 7

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention relates to a sheet conveyance device, an automatic document conveyance device, and an image forming apparatus.

Conventionally, a conveyance member that conveys a sheet, a sound collection section that collects operational sounds during sheet conveyance, a feature extraction section that extracts a feature amount of the operation sound collected by the sound collection section, and a system based on the feature amount. There is known a sheet conveyance apparatus that includes a conveyance abnormality determining section that determines whether or not a conveyance abnormality occurs.

Patent Document 1 discloses that the above-mentioned sheet conveying device provides a support vector machine with a feature amount that quantitatively expresses the characteristics of the operation sound collected by the sound collecting section, for the purpose of suppressing the occurrence of conveyance abnormalities. , which uses a machine learning model as index data to classify feature amounts into one of three classes: normal conveyance, document deformation, and paper feed slip. Then, when the feature quantity is classified as sheet slip or document deformation by the support vector machine, it is considered to be a conveyance abnormality, when it is classified as sheet slip, the conveyance member is heated, and when it is classified as document deformation, the paper feed cover is What opens is listed.

However, the operating sound collected by the sound collection unit during normal conveyance differs depending on the sheet conveyance conditions, and there is a risk of false judgments occurring with a single index data, so it is desired to suppress false judgments of conveyance abnormalities. .

In order to solve the above problems, the present invention includes a conveyance member that conveys a sheet, a sound collection section that collects operation sounds during sheet conveyance, and a feature amount of the operation sound collected by the sound collection section. For determining whether or not a conveyance abnormality occurs in a sheet conveying apparatus that includes a feature extraction unit that extracts a feature quantity, and a conveyance abnormality determination unit that determines whether or not a conveyance abnormality occurs based on the feature quantity. an index data selection section that selects index data corresponding to the conveyance conditions of the sheet from a plurality of index data serving as an index; and the conveyance abnormality determination section uses the index data selected by the index data selection section. , is characterized in that it is determined whether or not a conveyance abnormality occurs.

According to the present invention, erroneous determination of conveyance abnormality can be suppressed.

1 is a schematic configuration diagram showing a copying machine according to an embodiment. FIG. 3 is a partial enlarged configuration diagram showing a part of the internal configuration of the image forming section in the copying machine. FIG. 3 is a partially enlarged view showing a part of a tandem section including four process units in the image forming section. FIG. 3 is a perspective view showing the scanner and ADF of the copying machine. FIG. 3 is an enlarged configuration diagram showing the main part configuration of the ADF together with the upper part of the scanner. FIG. 3 is a block diagram showing part of the electric circuit of the ADF and the scanner. 7 is a flowchart of document conveyance abnormality determination processing in which index data to be used is selected based on the number of document sheets being conveyed as a conveyance condition. 7 is a flowchart of document conveyance abnormality determination processing in which index data to be used is selected based on the conveyance order of continuous document conveyance as a conveyance condition. 7 is a flowchart of document conveyance abnormality determination processing in which index data to be used is selected based on document conveyance speed as a conveyance condition.

Hereinafter, an embodiment in which the present invention is applied to an electrophotographic copying machine (hereinafter simply referred to as a copying machine), which is an image forming apparatus, will be described.
First, the basic configuration of a copying machine according to an embodiment will be described. FIG. 1 is a schematic configuration diagram showing a copying machine according to an embodiment. This copying machine includes an image forming section 1, a blank paper supply device 40, and a document reading device 50. The document reading device 50 includes a scanner 150 fixed above the image forming section 1 and an ADF 51 that is a document conveying device supported by the scanner 150.

The blank paper supply device 40 includes two paper feed cassettes 42 arranged in multiple stages in a paper bank 41, a delivery roller 43 that sends out the transfer paper from the paper feed cassette 42, and a paper feed path 44 that separates the sent out transfer paper. It has a separation roller 45 and the like for supplying the water. It also includes a plurality of conveyance rollers 47 and the like that convey the transfer paper to the paper feed path 37 of the image forming section 1 . Then, the transfer paper in the paper feed cassette is fed into the paper feed path 37 in the image forming section 1.

FIG. 2 is a partially enlarged configuration diagram showing an enlarged part of the internal configuration of the image forming section 1. As shown in FIG. The image forming unit 1 as an image forming means includes an optical writing device 2, four process units 3K, Y, M, and C that form toner images of K, Y, M, and C colors, and a transfer unit 24. . It also includes a paper conveyance unit 28, a pair of registration rollers 33, a fixing device 34, a switchback device 36, a paper feed path 37, and the like. Then, a light source such as a laser diode or an LED provided in the optical writing device 2 is driven to irradiate the four drum-shaped photoreceptors 4K, Y, M, and C with laser light L. By this irradiation, electrostatic latent images are formed on the surfaces of the photoreceptors 4K, Y, M, and C, and these latent images are developed into toner images through a predetermined development process. Note that the subscripts K, Y, M, and C added after the reference numerals indicate specifications for black, yellow, magenta, and cyan.

Each of the process units 3K, Y, M, and C supports the photoreceptor 4 and various devices disposed around it on a common support as one unit, and supports the image forming unit 1 main body. It is removable. Taking the black process unit 3K as an example, it includes a photoreceptor 4K and a developing device 6K for developing an electrostatic latent image formed on the surface of the photoreceptor into a black toner image. It also includes a drum cleaning device 15 that cleans transfer residual toner adhering to the surface of the photoreceptor 4K after passing through a primary transfer nip for K, which will be described later. This copying machine has a so-called tandem configuration in which four process units 3K, Y, M, and C are arranged opposite to an intermediate transfer belt 25, which will be described later, along its endless movement direction. There is.

FIG. 3 is a partially enlarged view showing a part of a tandem section consisting of four process units 3K, Y, M, and C. Note that the four process units 3K, Y, M, and C have almost the same configuration except that the toner colors used are different, so in the same figure, K, Y, M, and C are attached to each reference numeral. The subscript is omitted. As shown in the figure, the process unit 3 includes a charging device 5, a developing device 6, a drum cleaning device 15, a static elimination lamp 22, etc. around the photoreceptor 4.

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

The developing device 6 is configured to develop the latent image using a two-component developer containing a magnetic carrier and a non-magnetic toner. an agitation unit 7 for transporting the two-component developer contained therein while stirring and supplying it to the developing sleeve 12; and a stirring unit 7 for transferring the toner in the two-component developer supported on the developing sleeve 12 to the photoreceptor 4. It has a developing section 11.

The stirring section 7 is provided at a lower position than the developing section 11, and includes two conveying screws 8 arranged parallel to each other, a partition plate provided between these screws, and a bottom surface of the developing case 9. It has a toner concentration sensor 10 and the like.

The developing section 11 includes a developing sleeve 12 that faces the photoreceptor 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 brings its tip close to 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 a position facing the doctor blade 14 in the direction of rotation of the sleeve. These magnetic poles each apply a magnetic force to the two-component developer on the sleeve at a predetermined position in the rotational direction. As a result, the two-component developer sent from the stirring section 7 is attracted to the surface of the developing sleeve 12 and carried thereon, and a magnetic brush is formed along the lines of magnetic force on the sleeve surface.

When the magnetic brush passes through a position facing the doctor blade 14 as the developing sleeve 12 rotates, the layer thickness is regulated to an appropriate level, and then the magnetic brush is conveyed to a developing area facing the photoreceptor 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 photoreceptor 4, thereby contributing to development. Further, as the developing sleeve 12 rotates, the developing sleeve 12 returns to the developing section 11, and 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, it is returned to the stirring section 7. An appropriate amount of toner is replenished into the two-component developer in the stirring section 7 based on the detection result by the toner concentration sensor 10 . Note that instead of using a two-component developer as the developing device 6, one using a one-component developer that does not contain a magnetic carrier may be adopted.

As the drum cleaning device 15, a type in which a polyurethane rubber cleaning blade 16 is pressed against the photoreceptor 4 is used, but other types may be used. In order to improve the cleaning performance, this example employs a contact conductive fur brush 17 whose outer peripheral surface is brought into contact with the photoreceptor 4 and is rotatable in the direction of the arrow in the figure. This fur brush 17 also has the role of scraping the lubricant from the solid lubricant and applying it to the surface of the photoreceptor 4 while turning it into fine powder. A metal electric field roller 18 that applies 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 this roller. The toner adhering to the fur brush 17 is transferred to the electric field roller 18, which contacts the fur brush 17 in a counter direction and rotates to which a bias is applied. Then, after being scraped off from the electric field roller 18 by the scraper 19, it falls onto the collection screw 20. The collection screw 20 transports the collected toner toward the end of the drum cleaning device 15 in a direction perpendicular to the plane of the drawing, and transfers the collected toner to an external recycling transport device 21 . The recycling conveyance device 21 sends the received toner to the developing device 6 and recycles it.

The static elimination lamp 22 eliminates static electricity from the photoreceptor 4 by irradiating it with light. The surface of the photoreceptor 4 from which electricity has been removed is uniformly charged by the charging device 5, and then subjected to optical writing processing by the optical writing device 2. As the charging device 5, a device is used in which a charging roller to which a charging bias is applied is rotated while being brought into contact with the photoreceptor 4. A scorotron charger or the like that performs a non-contact charging process on the photoreceptor 4 may be used.

In FIG. 2 shown above, K, Y, M, and C toner images are formed on the photoreceptors 4K, Y, M, and C of the four process units 3K, Y, M, and C by the process explained so far. be done.

A transfer unit 24 is arranged below the four process units 3K, Y, M, and C. The transfer unit 24 moves an intermediate transfer belt 25 stretched by a plurality of rollers endlessly in the clockwise direction in the figure while contacting the photoreceptors 4K, Y, M, and C. As a result, primary transfer nips for K, Y, M, and C are formed in which the photoreceptors 4K, Y, M, and C are in contact with the intermediate transfer belt 25. Near the primary transfer nip for K, Y, M, C, the intermediate transfer belt 25 is transferred to the photoreceptors 4K, Y, M, by the primary transfer roller 26K, Y, M, C disposed inside the belt loop. It is pressing towards C. A primary transfer bias is applied to each of these primary transfer rollers 26K, Y, M, and C by a power source. As a result, a primary transfer electric field is formed in the primary transfer nip for K, Y, M, and C to electrostatically move the toner images on the photoreceptors 4K, Y, M, and C toward the intermediate transfer belt 25. has been done. Toner images are formed on the front surface of the intermediate transfer belt 25, which sequentially passes through the primary transfer nips for K, Y, M, and C as it moves endlessly in the clockwise direction in the figure. are sequentially superimposed and primary transferred. As a result of this superimposed primary transfer, a four-color superimposed toner image (hereinafter referred to as a 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 conveyance unit 28 is provided which extends an endless paper conveyance belt 29 between a drive roller 30 and a secondary transfer roller 31 to cause endless movement. The intermediate transfer belt 25 and paper conveyance belt 29 are sandwiched between the secondary transfer roller 31 and the lower tension roller 27 of the transfer unit 24. 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 conveyance belt 29 are in contact with each other. 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.

A pair of registration rollers 33 is disposed on the right side of the secondary transfer nip in the figure, and the secondary transfer is performed at a timing that allows the transfer paper sandwiched between the rollers to be synchronized with the four-color toner image on the intermediate transfer belt 25. Send it to the transfer nip. In the secondary transfer nip, the four-color toner image on the intermediate transfer belt 25 is secondary-transferred all at once onto 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, a full-color image is formed. The transfer paper that has passed through the secondary transfer nip is separated from the intermediate transfer belt 25 and is conveyed to the fixing device 34 while being held on the front surface of the paper conveyance belt 29 as it moves endlessly.

Transfer residual toner that was not transferred to the transfer paper in the secondary transfer nip adheres to the surface of the intermediate transfer belt 25 that has passed through the secondary transfer nip. This transfer residual toner is scraped off by a belt cleaning device that comes into contact with the intermediate transfer belt 25.

The transfer paper conveyed to the fixing device 34 has a full-color image fixed thereon by pressure and heat within the fixing device 34, and then is sent from the fixing device 34 to a pair of paper ejection rollers 35, and is then transported outside the machine. be discharged.

In FIG. 1 shown above, a switchback device 36 is disposed below the paper transport unit 28 and the fixing device 34. As a result, the transfer paper that has completed the image fixing process on one side is switched to the transfer paper reversing device side by the switching claw, where it is reversed and enters the secondary transfer nip again. After the image is subjected to secondary image transfer processing and fixing processing on the other side, the paper is discharged onto the paper discharge tray.

The scanner 150 fixed on the image forming section 1 has a first side fixed reading section 151 as a first side reading means and a movable reading section 152 as a first side reading means.

The movable reading unit 152 as a first side reading unit is disposed directly under a second contact glass 155 (see FIG. 4) fixed to the upper wall of the casing of the scanner 150 so as to be in contact with the original MS, and is provided with a light source. The optical system consisting of a mirror and a reflecting mirror can be moved in the left and right directions in the figure. Then, in the process of moving the optical system from the left side to the right side in the figure, the light emitted from the light source is reflected by the original MS placed on the second contact glass, and then passed through multiple reflecting mirrors. , the light is received by an image reading sensor 153 fixed to the scanner body.

A first surface fixed reading section 151 serving as a first surface reading means is disposed directly under a first contact glass 154 (see FIG. 4) fixed to the upper wall of the casing of the scanner 150 so as to be in contact with the original MS. There is. When the original MS transported by the ADF 51 (described later) passes over the first contact glass, the light emitted from the light source is sequentially reflected on the original surface and passed through a plurality of reflecting mirrors to the image reading sensor 153. Receive light. As a result, the first surface of the document MS is scanned without moving the optical system including the light source, reflection mirror, etc.

The scanner 150 also includes a contact image sensor 95 (see FIG. 5) that reads the second side of the document MS. This contact type image sensor 95 will be described later.

The ADF 51 disposed on the scanner 150 has a main body cover 52, a document mounting table 53 for placing the original MS before reading, a transport unit for transporting the original MS, and a stack for stacking the original MS after reading. It holds a document stacking table 55 and the like. As shown in FIG. 4, it is supported by a hinge 159 fixed to the scanner 150 so as to be swingable in the vertical direction. Then, by the swinging, it moves like an opening/closing door, and in the open state, the first contact glass 154 and the second contact glass 155 on the upper surface of the scanner 150 are exposed. In the case of a single-stitched original such as a book in which one corner of a bundle of originals is bound, the original MS cannot be separated one by one, and therefore cannot be transported by the ADF 51. Therefore, in the case of a single-sided bound document, after opening the ADF 51 as shown in FIG. close. Then, the image of that page is read by the movable reading section 152 of the scanner 150 shown in FIG.

On the other hand, in the case of a stack of originals in which a plurality of independent originals MS are simply stacked, the originals MS are automatically conveyed one by one by the ADF 51, and the first side fixed reading section 151 in the scanner 150 or the close contact in the ADF 51 The mold image sensor 95 can be read sequentially. In this case, after setting the document stack on the document table 53, the copy start button 158 (see FIG. 4) of the main body operation section 902 (see FIG. 6) is pressed. Then, the ADF 51 sequentially feeds the document MS of the document stack placed on the document stacking table 53 from the top, and conveys it toward the document stacking table 55 while reversing it. During this conveyance process, the document MS is passed directly above the first side fixed reading section 151 of the scanner 150 immediately after being reversed. At this time, the image on the first side of the document MS is read by the first side fixed reading section 151 of the scanner 150.

FIG. 5 is an enlarged configuration diagram showing the main part configuration of the ADF 51 together with the upper part of the scanner 150. Further, FIG. 6 is a block diagram showing part of the electric circuits of the ADF 51 and the scanner 150. As shown in FIG. 5, the ADF 51 includes a document setting section A, a separating section B, a registration section C, a turning section D, a first reading section E, a second reading section F, a paper ejection section G, and a stack section H. etc.

As shown in FIG. 6, the ADF 51 includes a controller 904 made of an ASIC (Application Specific Integrated Circuit) or the like, and can control various devices and sensors. The controller 904 is connected to a registration sensor 65, a document set sensor 63, a discharge sensor 61, an abutment sensor 72, a document width sensor 73, a reading entrance sensor 67, length sensors 57, 58, and the like. Also connected are a paper feed motor 191, a conveyance motor 192, a pullout clutch 193, a paper ejection clutch 194, a pickup motor 56, and the like. A sound collecting microphone 201 serving as a sound collecting section is also connected.

The sound collecting microphone 201 captures the sound when the document MS is conveyed. As shown in FIG. 5, in this embodiment, the sound collecting microphone 201 is attached to the inner circumferential surface of the paper feed cover 98, which can be opened and closed, and is located upstream of the document conveyance with respect to the pickup roller 80, which is the paper feed roller. It is arranged above the original placed on the side original placing table 53. In this embodiment, since the purpose is to collect the operational sound during document feeding, the sound is collected by placing it around the upstream side of the pickup roller 80, which is the most upstream side of the document conveyance that is driven during document feeding. ing.
Note that the sound collecting microphone 201 may be placed at an appropriate location between the pickup roller 80 and the paper feed belt 84 where there is no member to block the sound of the paper feeding/separation operation and where sound can be collected well. , may be placed. Further, by attaching the sound collecting microphone 201 to the inner peripheral surface of the paper feed cover 98, noise from the outside can be shielded by the paper feed cover 98, making it difficult for the sound collecting microphone 201 to pick up noise from the outside. Further, when attaching the sound collecting microphone 201 to the inner peripheral surface of the paper feed cover 98, a rubber-like vibration member may be attached therebetween to make it difficult to pick up noise due to vibration from the paper feed cover 98.
In addition, the sound generated during the document feeding operation (driving of the pickup roller 80), including the sound of the drive system of the pickup roller 80, which is a feeding roller, is collected as the operation sound during document feeding. Among the sounds generated during document feeding operation (driving of the pickup roller 80), the sound of the sheet due to the sheet feeding of the pickup roller 80, for example, is removed by removing the noise of the drive system using a pass filter or the like. , only sheet conveyance noise generated due to friction with the fed sheet or deformation of the sheet may be collected as the operation sound.

As shown in FIG. 6, the scanner 150 includes a reading control section 903 that includes 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. Further, the reading control unit 903 is connected to the controller 904 of the ADF 51 through an I/F, and the reading control unit 903 can also indirectly control various devices and sensors in the ADF 51 via the controller 904. .

In FIG. 5, the document setting section A includes a document placement table 53 on which a bundle of documents MS is set. Further, the separation and conveyance section B separates and feeds the originals MS one by one from the bundle of set originals MS. Further, the registration section C temporarily collides with the fed original MS to align the original MS and then sends out the original MS. Further, the turn section D has a curved conveyance section that is curved in a C-shape, and is used to turn the original MS upside down while folding it back within the curved conveyance section. In addition, while conveying the original MS on the first contact glass 154, the first reading conveyance section E moves to a first reading conveyance section E, which is disposed inside the scanner 150 below the first contact glass 154 as shown in FIG. This is to cause the fixed surface reading section 151 to read the first surface of the original MS. Further, the second reading and conveying unit F allows the contact type image sensor 95 to read the second side of the document MS while conveying the document MS under the contact type image sensor 95. Further, the paper discharge section G is for discharging the document MS whose images on both sides have been read toward the stack section H. Further, the stacking section H stacks the originals MS on the original stacking table 55.

The leading edge of the original MS is placed on a movable original table 54, which is a sheet tray that can swing in the directions of arrows a and b in the figure, depending on the thickness of the bundle of originals MS, and the rear end of the original is placed on a document mounting table. 53 and is set. At this time, the position in the width direction is adjusted by abutting side guides against both ends of the document placement table 53 in the width direction (direction perpendicular to the plane of the drawing). The document MS set in this manner pushes up a lever member 62 that is swingably disposed above the movable document table 54. Then, the document set sensor 63 detects the setting of the document MS and transmits a detection signal to the controller 904 (see FIG. 6). This detection signal is then sent from the controller 904 to the reading control unit 903 via the I/F.

The document table 53 holds a first length sensor 57 and a second length sensor 58, which are reflective photosensors or actuator type sensors that detect the length of the document MS in the conveying direction. These length sensors detect the length of the document MS in the conveyance direction.

A pickup roller 80 is disposed above the bundle of originals MS placed on the movable original table 54, and is supported by a cam mechanism so as to be movable in the vertical direction (in the direction of arrows c and d in the figure). . This cam mechanism can move the pickup roller 80 up and down by being driven by the pickup motor 56. When the pickup roller 80 moves upward, the movable document table 54 swings in the direction of arrow a in the figure, and the pickup roller 80 comes into contact with the top document MS in the bundle of documents MS. When the movable document table 54 further rises, the table rise sensor 59 eventually detects that the movable document table 54 has risen to the upper limit. As a result, the pickup motor 56 is stopped, and the movable original table 54 is stopped from rising.

The main body operation unit 902 (see FIG. 6), which consists of a numeric keypad, display, etc. provided on the main body of the copying machine, has a key for setting the reading mode to indicate whether the operator is in double-sided reading mode or single-sided reading mode. operations, pressing the copy start key, etc. That is, the main body operation unit 902 functions as a mode information acquisition unit that acquires information as to whether the mode is double-sided reading mode or single-sided reading mode. In addition, the reading modes include a thin paper mode for reading thin paper and a mixed loading mode for loading and transporting originals MS of different sizes.Thin paper mode and mixed loading mode can be set by the operator's key operation on the main body operation section 902. It can be performed. In the thin paper mode or the mixed loading mode, the original MS is transported at a slower overall transport speed than in the normal reading mode.

When the copy start key is pressed, a document feed signal is transmitted from the main body control unit 901 to the controller 904 of the ADF 51 via the I/F. Then, the pickup roller 80 is rotationally driven by the normal rotation of the paper feed motor 191, and sends out the original MS on the movable original table 54 from above the movable original table 54.

When setting the double-sided reading mode or the single-sided reading mode, it is possible to set double-sided or single-sided for all documents MS placed on the movable document table 54 at once. In addition, the reading mode can be changed individually for each original MS, such as setting the 1st and 10th original MS to double-sided reading mode, while setting the other original MS to single-sided reading mode. It is also possible to set

The document MS sent out by the pickup roller 80 enters the separation conveyance section B, and is sent to a contact position with the paper feed belt 84. The paper feed belt 84 is stretched between a drive roller 82 and a driven roller 83, and is endlessly moved in the clockwise direction in the figure by the rotation of the drive roller 82 as the paper feed motor 191 rotates normally. A separation roller 85 that is rotated clockwise in the figure by normal rotation of the paper feed motor 191 is in contact with the lower tension surface of the paper feed belt 84 . At the contact portion, the surface of the paper feed belt 84 moves in the paper feeding direction. On the other hand, the separation roller 85 is in contact with the paper feed belt 84 with a predetermined pressure, and when it is in direct contact with the paper feed belt 84 or when only one document MS is caught in the contact portion. In some cases, it is carried around by the belt or the original MS. However, when a plurality of documents MS are sandwiched between the abutting portions, the entraining force becomes lower than the torque of the torque limiter, so that the document MS is rotated clockwise in the figure, which is opposite to the entraining direction. As a result, the separation roller 85 applies a moving force in the opposite direction to the feeding direction to the documents MS below the topmost document MS, and only the topmost document MS is separated from the several sheets of documents MS.

The original MS separated into one sheet by the action of conveyance members such as the paper feed belt 84 and the separation roller 85 enters the registration section C. Then, when it passes directly under the abutment sensor 72, its tip is detected. At this time, the pickup roller 80 receiving the driving force of the paper feed motor 191 is still being driven to rotate, but as the movable document table 54 is lowered and separated from the document MS, the document MS is moved by the endless movement of the paper feed belt 84. Transported by force only. Then, the endless movement of the paper feed belt 84 continues for a predetermined period of time from the timing when the leading edge of the document MS is detected by the abutment sensor 72. Thereafter, the leading edge of the document MS abuts against a contact portion between the pull-out driven roller 86, which is a transport member, and the pull-out drive roller 87, which is a transport member, and which is rotated while being in contact with the pull-out driven roller 86. With the leading edge of the original MS in contact with the contact portions of both rollers, the trailing edge of the original MS is fed toward the paper feeding direction, causing the original MS to be bent by a predetermined amount while the leading edge is It is positioned at the contact part. As a result, the skew (inclination) of the original MS is corrected, and the original MS is placed in a posture along the paper feeding direction.

In addition to the role of correcting the skew of the document MS, the pull-out drive roller 87 also has the role of conveying the document MS whose skew has been corrected to the intermediate roller pair 66, which is a downstream conveyance member in the document 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 rollers of the intermediate roller pair 66 are connected to the paper feed motor 191 via a one-way clutch. A one-way clutch connected to the pull-out drive roller 87 and the drive rollers of the intermediate roller pair 66 transmits driving force when the paper feed motor 191 reverses, and a one-way clutch connected to the drive roller 82 transmits the drive force when the paper feed motor 191 reverses. Transmits driving force during rotation. Therefore, when the paper feed motor 191 reverses, the pull-out drive roller 87 and the drive rollers of the intermediate roller pair 66 start rotating, and the endless movement of the paper feed belt 84 stops. Further, at this time, the rotation of the pickup roller 80 is also stopped.

The document MS sent out from the pull-out drive roller 87 passes directly below the document width sensor 73. The document width sensor 73 has a plurality of paper detection sections each including a reflective photosensor or the like, and these paper detection sections are lined up in the document width direction (direction perpendicular to the plane of the drawing). The size of the document MS in the width direction is detected based on which paper detection section detects the document MS. Further, the length of the document MS in the transport direction is detected based on the timing from when the leading edge of the document MS is detected by the abutting sensor 72 until the trailing edge of the document MS is no longer detected by the abutting sensor 72. .

The leading edge of the document MS, whose size in the width direction has been detected by the document width sensor 73, enters the turn portion D and is sandwiched between the rollers of the pair of intermediate rollers 66. The conveyance speed of the document MS by the pair of intermediate rollers 66 is set higher than the conveyance speed of the document MS in the first reading conveyance section E, which will be described later. As a result, the time required to send the document MS to the first reading conveyance section E is shortened.

The leading edge of the original MS being conveyed in the turn section D passes through a position facing the reading entrance sensor 67 . As a result, when the leading edge of the document MS is detected by the reading entrance sensor 67, the leading edge of the document MS is conveyed to the position of the reading entrance roller pair (a pair of 89 and 90), which is a conveying member on the downstream side in the conveying direction. Then, the document conveyance speed by the intermediate roller pair 66 is reduced. Furthermore, with the start of rotation of the conveyance motor 192, one roller of the pair of reading entrance rollers (89, 90), one roller of the pair of reading exit rollers 92, and one roller of the pair of second reading exit rollers 93 are rotated. Each starts rotating.

In the turn section D, while the document MS is being conveyed on the curved conveyance path between the pair of intermediate rollers 66 and the pair of reading entrance rollers (89, 90), the upper and lower surfaces are reversed and the conveyance direction is turned back. . Then, the leading edge of the document MS that has passed through the nip between the rollers of the reading entrance roller pair (89, 90) passes directly under the registration sensor 65. At this time, when the leading edge of the document MS is detected by the registration sensor 65, the document conveyance speed is decelerated while applying a predetermined conveyance distance, and the conveyance of the document MS is temporarily stopped before the first reading conveyance section E. . Further, a temporary stop signal is transmitted to the reading control unit 903 via the I/F.

When the reading control unit 903 that has received the pause signal transmits a reading start signal, the rotation of the transport motor 192 is restarted under the control of the controller 904 until the leading edge of the document MS reaches the inside of the first reading transport unit E. The transport speed of the document MS is increased to a predetermined transport speed. Then, at the timing when the leading edge of the document MS reaches the reading position by the first side fixed reading section 151, a gate signal is sent from the controller 904 to the reading control section 903 indicating the effective image area in the sub-scanning direction on the first side of the document MS. is sent. This transmission continues until the rear end of the original MS passes through the reading position by the first side fixed reading unit 151, and the first side of the original MS is read by the first side fixed reading unit 151. Note that the timing at which the leading edge of the document MS reaches the reading position by the first side fixed reading unit 151 is calculated based on the pulse count of the transport motor 192.

The document MS that has passed through the first reading and conveying section E passes through a pair of reading exit rollers 92, which will be described later, and then its leading edge is detected by the sheet discharge sensor 61. When the single-sided reading mode is set, it is not necessary to read the second side of the document MS by the contact image sensor 95, which will be described later. Therefore, when the leading edge of the document MS is detected by the paper ejection sensor 61, the driving force of the transport motor 192 is connected to the paper ejection roller pair 94 by the paper ejection clutch 194, and the paper ejection The paper roller is rotated clockwise in the figure. Further, the timing at which the trailing edge of the document MS exits the nip between the pair of paper discharge rollers 94 is calculated based on the pulse count of the transport motor 192 after the leading edge of the document MS is detected by the paper discharge sensor 61 . Then, based on this calculation result, the driving force of the transport motor 192 is cut off by the paper ejection clutch 194 to stop the paper ejection roller pair 94.

On the other hand, when the double-sided scanning mode is set, the timing from when the leading edge of the document MS is detected by the paper ejection sensor 61 until it reaches the contact image sensor 95 is based on the pulse count of the transport motor 192. Calculated. Then, at that timing, the controller 904 transmits a gate signal indicating the effective image area in the sub-scanning direction on the second side of the document MS to the reading control unit 903. This transmission continues until the rear end of the document MS passes through the reading position by the contact type image sensor 95, and the second side of the document MS is read by the contact type image sensor 95.

The contact image sensor 95 (CIS) serving as the second side reading means is coated with a coating on the reading surface in order to prevent vertical reading streaks caused by glue-like foreign matter adhering to the document MS adhering to the reading surface. is applied. At a position facing the contact image sensor 95, a second reading roller 96 is disposed as a document supporting means for supporting the document MS from the non-reading surface side (first surface side). This second reading roller 96 has the role of preventing the document MS from floating at the reading position by the contact type image sensor 95 and functioning as a reference white part for acquiring shading data in the contact type image sensor 95. There is. In this copying machine, the second reading roller 96 is used as a document support means for supporting the document MS at a position facing the contact image sensor 95, but a guide plate-like device may also be used.

When the pickup roller 80 feeds the original MS, the original MS is conveyed against the frictional force with the original directly below the original MS to be fed or the movable original table 54, so that the original MS is moved against the pickup roller 80. slippage is likely to occur. In addition, slipping is likely to occur as the pickup roller 80 and the movable document table 54 move up and down and the contact state with the document changes. When the slip occurs, the document MS may not be conveyed to a specified position within a predetermined time, which may result in a paper jam.

If a paper jam occurs due to a conveyance error after the document MS has been conveyed to some extent within the ADF, it will not be easy to take out the document MS, and the document MS will be wrinkled or torn when the document MS is taken out, causing damage to the document MS. There is a risk of giving.

Further, the user may inadvertently set a bundle of a plurality of documents MS bound with staples or clips on the document table 53. When such a bundle of bound original documents MS is fed, there is a possibility that paper jams may occur at the separation portion, which is the contact portion of the separation roller 85 with the paper feed belt 84. Furthermore, when the leading edge of a bundle of multiple originals MS bound with metal pieces such as staples and clips enters the separating section, the uppermost original in the bundle of originals MS is continuously transported by the paper feed belt 84. Ru. However, the second and subsequent documents are given a conveyance force to be returned by the separation roller 85. As a result, a large stress is applied to the parts bound by the metal pieces, causing tears, folds, wrinkles, etc. to occur in the document MS, which may cause damage to the document MS.

Therefore, in this embodiment, it is predicted and determined whether or not there is a risk of a paper jam occurring from the operation sound during document feeding, which is collected by the sound collecting microphone 201. If there is a possibility that a paper jam may occur, the conveyance of the original MS is stopped to prevent the occurrence of a paper jam and prevent damage to the original MS. Furthermore, when the apparatus is stopped, a message may be displayed on the display panel of the main body operation unit 902 that a paper jam may occur, or a warning sound may be emitted from the speaker.

In this embodiment, a feature amount that quantitatively expresses the characteristics of the operating sound during document transport collected by the sound collecting microphone 201 is extracted, and based on the extracted feature amount, the MT method (Mahalanobis Taguchi method) is applied to the original document. Performs transport abnormality determination. The MT method is one of the MT (Mahalanobis Taguchi) systems known for prediction, diagnosis, and analysis using multidimensional information data in fields such as quality engineering. The MT method is one of the methods that can determine whether data is normal or abnormal using the Mahalanobis distance, and is a method that can easily and relatively accurately determine whether data is normal or abnormal. The MT method is a well-known method described in, for example, Japanese Patent Application Publication No. 2003-141306 and Genichi Taguchi's "Mathematics of Quality Engineering" (Japanese Standards Association, published in 1999), so a detailed explanation is not provided. Omitted.

The following data is stored in advance in the ROM of the controller 904 as index data used to determine transport abnormality. That is, the inverse matrix R-1 of the correlation matrix of the unit space data set (reference data set) used when calculating the Mahalanobis distance, and the threshold Th for classifying the calculated Mahalanobis distance into normal transport or abnormal transport. be.

The inverse matrix R-1 is obtained by creating a unit space data set (reference data set) in advance based on the feature amount obtained from the operation sound of the document MS being normally conveyed. The threshold Th for classifying the calculated Mahalanobis distance into normal transport or abnormal transport is determined by calculating in advance the Mahalanobis distance at which the false negative rate (misjudgment rate of normal judgment) and false positive rate (misjudgment rate of abnormal transport) are below the target values. Set.

However, if conveyance abnormality determination is performed using one index data consisting of the inverse matrix R-1 and the threshold Th obtained from one unit space data set (reference data set), the accuracy of conveyance abnormality determination may decrease. there were. This is because, when two or more documents MS are being transported, the sound collection microphone 201 picks up the transport sound of the preceding document that has passed through the pickup roller 80 in addition to the operational sound during document feeding. Therefore, the operating sound during normal transport when there is a preceding document being transported is significantly different from the operating sound during normal transport when there is no preceding document being transported. Therefore, the feature amount obtained from the operating sound during normal transport when there is a preceding document being transported, and the feature amount obtained from the operating sound during normal transport when there is no preceding document being transported. The unit space data set (reference data set) that has been created has a large variation. As a result, the accuracy of the inverse matrix R-1 and the threshold Th obtained based on this unit space data set decreases, and it is not possible to accurately determine a conveyance abnormality. As a result, there is a possibility that an erroneous determination of normal transport or an erroneous determination of abnormal transport may occur.

Therefore, in this embodiment, a plurality of index data are prepared in advance, and the optimal index data (inverse matrix R-1 and threshold Th) according to the number of documents being transported as transport conditions is used to determine transport abnormality. I decided to do it. Characteristic parts of this embodiment will be described below with reference to the drawings.

FIG. 7 is a flowchart of document conveyance abnormality determination processing for each document, which is executed by the controller 904.
In this embodiment, in order to increase the reading throughput, a plurality of originals MS are fed simultaneously on the original transport path, in order to continuously feed the originals MS while keeping an interval between the originals MS as sheets so that they do not overlap each other. exist at intervals. Therefore, the document conveyance abnormality determination process shown in FIG. 7 is executed concurrently.

When the controller 904 receives the document feed signal from the main body control unit 901, it sets the "number of documents being transported" counter on the RAM of the controller 904 to zero. Then, the controller 904 increments the "number of documents being transported" counter by 1 (S1), and then starts the paper feeding/separation operation (S2). Regarding the first original document MS, the count value "0" is incremented by one. For the second document MS that is continuously conveyed, the current count value "1" is incremented by one. As will be described later, this "number of originals being transported" is decremented by 1 from the current count value of "number of originals being transported" at the timing when the original MS passes through the paper ejection roller pair 94. As a result, the "number of originals being transported" temporarily stored in the RAM of the controller 904 becomes the number of originals currently being transported within the ADF 51.

The controller 904 uses the sound collection microphone 201 to collect operation sounds during document feeding at the same time as the paper feeding/separation operation starts (S3), and temporarily stores the collected operation sound sound signals in the RAM of the controller 904. Remember.

Next, the controller 904 calculates the feature amount of the operation sound stored in this RAM (S4). Specifically, short-time Fourier transform (STFT) is performed on the sound signal of the operation sound stored in the RAM, and the time sequence of the power spectrum of the sound signal is calculated. Next, a characterization process is performed on the time array of the calculated power spectrum to calculate the feature amount of the operating sound. As the characterization process, time integration of power in a predetermined frequency band, spectral flux between consecutive frames, etc. can be used. That is, in this embodiment, the controller 904 functions as a feature extracting unit. Note that the feature amount quantitatively expressing the feature of the operating sound used for determining the operating state is not limited to the above, and a known sound feature amount such as Mel frequency cepstral coefficient may be used.

After calculating the feature amount, it is determined whether or not a conveyance abnormality occurs based on the calculated feature amount. In this embodiment, the index data used for determining the conveyance abnormality is based on the number of documents being conveyed. (Inverse matrix R-1 and threshold Th) are selected.

Specifically, the controller 904 checks the "number of documents being transported" on the RAM of the controller 904. If the "number of originals being transported" is two or more, that is, if there is a preceding original being transported (Y in S5), index data for the case where there is a preceding original being transported is selected (S7). On the other hand, when the "number of originals being transported" is less than 2, that is, when there is no preceding original being transported (N in S5), index data for when there is no preceding original being transported is selected (S6). . That is, in this embodiment, the controller 904 has a function as an index data selection section.

The inverse matrix R-1, which is one of the index data when there is a preceding document being transported, is a unit space created in advance based on the feature amount of the operation sound during normal transport when there is a preceding document being transported. Determined from the data set (reference data set). In addition, the threshold Th, which is one of the index data when there is a preceding document being transported, is the Mahalanobis distance at which the false negative rate and false positive rate are below the target value for this unit space data set (reference data set). is determined and set in advance.

The unit space data set created based on the feature amount of the operating sound during normal transport when there is a preceding document being transported includes the feature amount of the operating sound during normal transport when there is no preceding document being transported. is not included. Therefore, variations in the unit space data set (reference data set) can be reduced, and the inverse matrix R-1 and threshold Th that are optimized for determining transport abnormality when there is a preceding document being transported can be obtained.

The inverse matrix R-1, which is one of the index data when there is no preceding document being transported, is a unit space created in advance based on the feature amount of the operation sound during normal transport when there is no preceding document being transported. Determined from the data set (reference data set). In addition, the threshold Th, which is one of the index data when there is no preceding document being transported, is the Mahalanobis distance at which the false negative rate and false positive rate are below the target value for this unit space data set (reference data set). is determined and set in advance.

The unit space data set created based on the feature amount of the operating sound during normal transport when there is no preceding original being transported includes the feature amount of the operating sound during normal transport when there is a preceding original being transported. is not included. Therefore, variations in the unit space data set (reference data set) can be reduced, and the inverse matrix R-1 and threshold Th that are optimized for determining transport abnormality when there is no preceding document being transported can be obtained.

After selecting the transportation abnormality determination model, the controller 904 performs transportation abnormality determination using the MT method based on the feature amount of the operation sound (S8). Conveyance abnormality is determined at the timing when the document has been conveyed a predetermined distance from the document set position. Whether or not the paper has been conveyed a predetermined distance is determined using the number of drive pulses of the paper feed motor 191, the elapsed time from the start of drive of the paper feed motor 191, and the like.

The above-mentioned "predetermined distance" is shorter than the distance from the leading edge position of the original MS set on the original placing table 53 to the separation part (separation nip) where the separation roller 85 is in contact with the paper feed belt 84. Preferably, the distance is set. By setting such a distance, a conveyance abnormality can be determined before the leading edge of the document MS reaches the separating section. This makes it possible to stop the conveyance operation before the leading edge of a bundle of multiple originals MS bound with metal pieces such as staples and clips enters the separating section, causing damage to the originals MS. can be suppressed.

In the conveyance abnormality determination, first, the controller 904 inputs the sound feature amounts calculated up to that point and calculates the Mahalanobis distance using the inverse matrix R-1 corresponding to the selected conveyance condition. Next, the controller 904 determines whether the calculated Mahalanobis distance is less than or equal to a threshold Th corresponding to the conveyance condition. If the calculated Mahalanobis distance is less than or equal to the threshold Th, it is determined that the conveyance is normal, and if it is greater than the threshold Th, it is determined that the conveyance is abnormal.

In this embodiment, a conveyance abnormality determination is performed using index data (inverse matrix R-1 and threshold Th) according to the conveyance condition of whether or not there is a preceding document being conveyed. As described above, these index data are created based on the operation sounds during normal transport under each transport condition, and are optimized for transport abnormality determination under each transport condition. Therefore, it is possible to accurately determine the conveyance abnormality, and it is possible to satisfactorily suppress erroneous determinations.

If it is determined that the document is transported normally, the document transport process described above is executed. That is, after the paper feeding/separation operation is completed (S9), the paper feeding motor 191 is reversed, and a pullout operation is performed in which the skew-corrected document is sent out by the pullout drive roller 87 (S10). Then, a temporary stop process is performed to temporarily stop the conveyance of the document MS before the first reading conveyance section E (S11). After that, it waits for the reception of a reading start signal from the reading control unit 903 (S12), and after receiving it (Y in S12), the conveyance of the original MS is restarted, and the original MS is transferred to the first reading conveyance unit E and the second reading conveyance unit. A reading conveyance process is started in which the sheets are conveyed sequentially to section F and discharge section G (13).

When the leading edge of the document MS is detected by the sheet discharge sensor 61, the pulses of the sheet discharge motor are counted, and the timing at which the trailing edge of the document MS exits the nip between the pair of sheet discharge rollers 94 is calculated. Next, based on this calculation result, the operation of the paper ejection clutch 194 is stopped, and the "number of originals being transported" counter is decremented by 1 (S14).
On the other hand, if it is determined that the conveyance is abnormal, the conveyance operation of all the documents MS being conveyed is stopped (S21), and the reading operation is ended.

In the above, the controller 904 grasps the number of originals being conveyed, and the index data (inverse matrix R-1 and threshold Th) is selected based on the grasped number of originals being conveyed. Index data may be selected based on the order. Regarding the first page original MS that is transported first, there is no preceding original that is being transported, but from the second page onward, there is a preceding original that is being transported, so it is collected when the second and subsequent pages are fed. The operation sound collected by the sound microphone 201 also picks up the sound of the preceding document being conveyed. Therefore, the index data to be used may be selected based on the conveyance order of continuous document conveyance as the conveyance condition.

Furthermore, even if the device is such that the sound collection microphone 201 hardly picks up the sound of the preceding document being conveyed, so that the influence of the conveying sound of the preceding document is negligible, the following conveyance control is performed during continuous document conveyance. When there are two pages, the operation sound collected by the sound collecting microphone 201 on the first page may be different from the operation sound on the second and subsequent pages. That is, this is a case where transport control is performed to increase productivity by increasing the transport speed at the paper feeding/separating/abutting section only for the first page of the document that is transported first. If the document conveyance speed differs, the frequency characteristics of the operation sound collected by the sound collecting microphone 201 will differ. Further, when the operation sound is acquired until the document MS is conveyed a predetermined distance, the time of the operation sound to be acquired also differs. As a result, the operating sound during normal conveyance differs between the first page and the second and subsequent pages. Therefore, a unit space data set (reference data set) consisting of the feature amount obtained from the operation sound during normal conveyance of the first page and the feature amount obtained from the operation sound during normal conveyance from the second page onward is as follows: Variability increases. As a result, as described above, the accuracy of index data such as the inverse matrix R-1 and the threshold Th decreases, and there is a possibility that accurate conveyance abnormality determination cannot be performed.

Therefore, even when performing control to increase the transport speed at the paper feeding/separating/abutment section for the first page of original MS to be transported in continuous document transport, the transport conditions are based on the transport order of continuous document transport. You may also select the index data to use. Further, the index data to be used may be selected based on the conveyance speed and paper quality as conveyance conditions.

FIG. 8 is a flowchart of document conveyance abnormality determination processing in which index data to be used is selected based on the conveyance order of continuous document conveyance as a conveyance condition.
In continuous document conveyance, as described above, since a plurality of documents exist on the document conveyance path, the flow shown in FIG. 8 is also executed in parallel for each document being fed.

First, upon receiving a document feed signal from the main body control unit 901, the controller 904 sets a "page number" counter on the RAM of the controller 904 to 0. Next, the controller 904 increments the "page number" by 1 (S1) and starts the paper feeding/separation operation (S2).

Next, in the same manner as described above, the sound collection microphone 201 collects the operation sound during document feeding (S3), and the feature amount of the operation sound is calculated in the same manner as described above (S4). Next, the controller 904 checks the "page number" on the RAM of the controller 904. When the "page number" is "1" (N in S5), index data for the first page of the document is selected (S6). On the other hand, if the "page number" is "2" or more (Y in S5), the index data for the document from page 2 onward is selected (S6).

The index data (inverse matrix R-1 and threshold Th) for the first page document is a unit space data set ( This was determined from the standard data set). This unit space data set does not include the feature amount of the operation sound during normal conveyance of the second and subsequent pages, which has a different frequency etc. from the operation sound during document conveyance of the first page. Therefore, variations in the unit space data set (reference data set) can be reduced, and from this unit space data set (reference data set), index data (inverse matrix R-1 and threshold value Th) can be determined.

The index data for the document from page 2 onwards is obtained from a unit space data set (reference data set) created in advance based on the feature amount of the operating sound during normal transport of the document MS from page 2 onwards. be. This unit space data set does not include the feature amount of the operation sound during normal conveyance of the first page, which has a different frequency, etc. from the operation sound during document conveyance of the second and subsequent pages. Therefore, variations in the unit space data set (reference data set) can be reduced, and from this unit space data set (reference data set), index data ( The inverse matrix R-1 and the threshold value Th) can be obtained.

Next, the controller 904 uses the MT method to determine a conveyance abnormality based on the feature amount of the operation sound calculated up to that point and the index data corresponding to the selected conveyance condition (S8). Specifically, as described above, the feature amount of the operation sound calculated up to that point is input, and the Mahalanobis distance is calculated using the inverse matrix R-1 corresponding to the selected transport condition. Next, the controller 904 determines that the conveyance is normal if the calculated Mahalanobis distance is less than or equal to the threshold Th corresponding to the conveyance condition, and determines that the conveyance is abnormal if it is greater than the threshold Th.

If it is determined that the document is transported normally, the original transport process is executed in the same manner as described above (S9 to S13). On the other hand, when it is determined that the conveyance is abnormal, the conveyance operation of all the documents MS being conveyed is stopped (S21), and the reading operation is ended.

In this way, in the flow of FIG. 8, the index data (inverse matrix R-1 and threshold Th) optimized for determining abnormality in document transportation for the first page and for determining abnormality in document transportation for pages 2 and onwards are used. It includes optimized index data (inverse matrix R-1 and threshold Th). Then, index data corresponding to the order of transportation is selected as the transportation condition, and transportation abnormality determination is performed using the selected index data. As a result, abnormal conveyance can be accurately performed for both the first page of the document and the second and subsequent pages.

Furthermore, as described above, this embodiment has a thin paper mode for reading thin paper and a mixed loading mode for loading and conveying manuscripts MS of different sizes. In the thin paper mode and the mixed loading mode, the document MS is conveyed at a slower overall document conveyance speed than in the normal reading mode. If the document conveyance speed differs, the frequency characteristics of the operating sound and the time of the acquired operating sound will differ. Therefore, a unit space data set (reference data set) consisting of characteristic amounts of operation sounds during normal document transport at different document transport speeds has a large variation. Therefore, as described above, the accuracy of index data such as the inverse matrix R-1 and the threshold Th decreases, and there is a possibility that accurate conveyance abnormality determination cannot be performed.

Therefore, a plurality of index data corresponding to the document conveyance speed may be stored in the ROM of the controller 904 as the conveyance condition, and index data to be used for conveyance abnormality determination may be selected based on the document conveyance speed. In the present embodiment, the document conveyance speed is set to the conveyance speed when passing through the separation section (the contact section between the separation roller 85 and the paper feed belt 84). However, this is just an example, and for example, the average conveyance speed from the start of feeding by the pickup roller 80 until the document MS reaches the separating section may be used.

FIG. 9 is a flowchart of document conveyance abnormality determination processing in which index data to be used is selected based on the document conveyance speed as the conveyance condition.
When the operator presses the copy start key, a document feed signal is transmitted from the main body control unit 901 to the controller 904. At the same time, the main body control unit 901 notifies the controller 904 of setting information such as a thin paper mode for reading thin paper and a mixed loading mode. The controller 904 comprehensively determines the transport speed of the document MS based on the setting information sent from the main body control unit 901.

Thereafter, at the same time as starting the paper feeding/separating operation at the determined transport speed, the sound collecting microphone 201 collects the operating sound during document feeding, and calculates the feature amount of the operating sound (S1 to S4).

Next, the controller 904 selects index data corresponding to the transport speed determined as the transport condition (S4 to S10). In FIG. 9, there are four document transport speeds A to D, which are set according to the reading mode, etc., and index data corresponding to each transport speed is stored in the ROM of the controller 904. Each index data is an inverse matrix R-1 and a threshold Th obtained from a unit space data set (reference data set) consisting of feature quantities of operation sounds during normal transport at the corresponding transport speed. The inverse matrix R-1 and the threshold Th can be obtained from a unit space data set (reference data set) with little variation, and are the inverse matrix optimized for determining abnormality in conveyance of the document MS conveyed at the corresponding conveyance speed. Matrix R-1 and threshold Th can be used.

Next, the controller 904 performs transport abnormality determination using the MT method based on the feature amount of the operation sound calculated up to that point and the index data corresponding to the selected transport speed (S8). Specifically, the calculated feature amount of the operation sound is input, and the Mahalanobis distance is calculated using the inverse matrix R-1 of the index data corresponding to the selected transport speed. Next, the controller 904 determines that the conveyance is normal if the calculated Mahalanobis distance is less than or equal to the threshold Th corresponding to the conveyance condition, and determines that the conveyance is abnormal if it is greater than the threshold Th.

Then, as described above, if it is determined that the document is being transported normally, the document transporting process is executed (S12 to S16). On the other hand, when it is determined that the conveyance is abnormal, the conveyance operation of all the documents MS being conveyed is stopped (S21), and the reading operation is ended.

In the flow shown in FIG. 9, transport abnormality can be determined using index data such as the inverse matrix R-1 and the threshold Th, which are optimized for each transport speed as transport conditions, and transport abnormality can be determined with high accuracy. It can be performed.

Further, for example, when there is a preceding document being transported, four index data corresponding to each transport speed are provided, and when there is no preceding document being transported, four index data corresponding to each transport speed are provided. Then, the corresponding index data may be selected based on whether there is a preceding document being transported and the determined transport speed. Thereby, it is possible to perform a conveyance abnormality determination with even higher accuracy.

In this embodiment, the transport abnormality is determined using the MT method, but the feature amount of the operation sound may be classified into normal transport and transport abnormality by machine learning such as a support vector machine. In this case, a plurality of learned models corresponding to the transport conditions are stored in the ROM of the controller 904 as index data. Each trained model is obtained by machine learning based on the feature amount of operation sound and correct data (normal transport/abnormal transport) when documents are transported under the corresponding transport conditions. , each optimized for the corresponding transport conditions.
The controller 904 selects a learned model according to the conveyance conditions, uses the selected learned model to classify the feature amount of the operation sound into either normal conveyance or abnormal conveyance, and performs a conveyance abnormality determination.
Even in such a configuration, it is possible to accurately determine a conveyance abnormality using a learned model that is optimized for the conveyance conditions.

In the above description, an example has been described in which the present invention is applied to the ADF 51 as a sheet conveyance device, but the present invention can also be applied to a printer as a conveyance device that conveys the transfer paper of the image forming section 1, and is an image forming apparatus. It can also be applied to inkjet type copying machines.

What has been described above is just an example, and each of the following aspects has its own unique effects.
(Aspect 1)
A conveyance member such as a pickup roller 80 that conveys a sheet such as a document MS, a sound collection unit such as a sound collection microphone 201 that collects operation sounds during sheet conveyance, and feature quantities of the operation sounds collected by the sound collection unit. (In this embodiment, a feature extraction unit such as a controller 904 that extracts the time integration of power in a frequency band, spectral flux between consecutive frames, etc.) and a feature extraction unit that extracts whether a transport abnormality occurs based on the feature In a sheet conveying apparatus that includes a conveyance abnormality determination unit such as a controller 904 that determines whether or not a conveyance abnormality occurs, a plurality of index data (in this embodiment, an inverse matrix R- 1 and a threshold value Th), the transport abnormality determination section uses the index data selected by the index data selection section to Determine whether or not a conveyance abnormality occurs.
According to this, it is determined whether or not a sheet conveyance abnormality occurs using index data corresponding to the sheet conveyance conditions, so it is possible to perform a highly accurate determination of a conveyance abnormality, and to suppress false determinations. be able to.

(Aspect 2)
In aspect 1, the sheet conveyance condition is the number of sheets being conveyed other than the sheet to be determined for conveyance abnormality.
According to this, as explained using FIG. 7, a conveyance abnormality can be determined using optimal index data according to the number of sheets being conveyed other than the sheet to be determined for conveyance abnormality. Conveyance abnormalities can be easily determined.

(Aspect 3)
In aspect 2, the conveyance condition for a sheet such as the original MS is whether or not there is a sheet being conveyed other than the sheet to be determined for conveyance abnormality.
According to this, as described in the embodiment, the sound collecting section such as the sound collecting microphone 201 picks up the operation sound of the sheet being transported other than the sheet that is the target of the transport abnormality determination. The operating sound during normal conveyance differs depending on whether there is a sheet being conveyed. Therefore, by changing the index data used for determining a conveyance abnormality depending on whether there is a sheet being conveyed other than the sheet to be determined for a conveyance abnormality, it is possible to accurately determine a conveyance abnormality.

(Aspect 4)
In aspect 1, the sheet conveyance condition is the order of conveyance of sheets to be determined for conveyance abnormality in a continuous sheet conveyance operation.
According to this, as explained using FIG. 8, a conveyance abnormality can be determined using optimal index data according to the sheet conveyance order, and a conveyance abnormality can be determined with high accuracy. Can be done.

(Aspect 5)
In aspect 4, in continuous sheet conveyance, control is performed to make the conveyance speed of the first conveyed sheet faster than the conveyance speed of the second and subsequent sheets, and the sheet conveyance conditions are This is whether or not the sheet is to be conveyed.
According to this, as described in the embodiment, the operation sound during normal conveyance of the first sheet conveyed at a higher conveyance speed than the conveyance speed of the second and subsequent sheets is different from that during normal conveyance of the second and subsequent sheets. The operating sound is different. Therefore, by changing the index data used for determining a conveyance abnormality depending on whether or not the sheet is the first sheet to be conveyed in a continuous sheet conveying operation, it is possible to accurately determine a conveyance abnormality.

(Aspect 6)
In any one of aspects 1 to 5, the sheet conveyance condition is the sheet conveyance speed.
According to this, as explained using FIG. 9, a conveyance abnormality can be determined using optimal index data according to the sheet conveyance speed.

(Aspect 7)
In any of Aspects 1 to 6, when a conveyance abnormality determination unit such as the controller 904 determines that a conveyance abnormality occurs, the sheet conveyance operation is stopped.
According to this, as described in the embodiment, it is possible to stop the conveyance operation of the sheet such as the original MS before a jam occurs, and it is possible to suppress damage to the sheet.

(Aspect 8)
In any of Aspects 1 to 7, the operating sound is the operating sound of a feeding roller such as the pickup roller 80 that feeds the sheet placed on the sheet tray.
According to this, as described in the embodiment, it becomes possible to determine whether or not abnormal conveyance occurs in the abnormality determination section before the sheets are conveyed to the separation section, and it is possible to determine whether abnormal conveyance occurs or not. It is possible to prevent damage to the sheets, such as tears and wrinkles, caused by the sheet bundle being conveyed to the separating section, and it is possible to protect the sheets.

(Aspect 9)
In any one of aspects 1 to 8, the operation sound is a sheet conveyance sound when a sheet placed on a sheet tray is fed.
According to this, as described in the embodiment, it becomes possible to determine whether or not abnormal conveyance occurs in the abnormality determination section before the sheets are conveyed to the separation section, and the It is possible to prevent damage to the sheets, such as tears and wrinkles, caused by the sheet bundle being conveyed to the separating section, and it is possible to protect the sheets.

(Aspect 10)
In an automatic document feeder that includes a document sheet conveyance section that conveys a document sheet such as a document MS, and in which the document sheet conveyance section conveys the document sheet to an image reading section, the sheet according to any one of Aspects 1 to 9 is used as the document sheet conveyance section. A transport device was used.
According to this, it is possible to suppress the occurrence of jams, and to suppress damage such as folds, wrinkles, and tears to the original sheet.

(Aspect 11)
An image forming apparatus that forms an image on a sheet conveyed by a sheet conveyance section includes the sheet conveyance device according to aspects 1 to 9 as the sheet conveyance section, or includes an automatic document conveyance device such as the ADF 51 of aspect 9.
According to this, it is possible to prevent damage to the sheet and damage to the original sheet.

50: Original reading device 51: ADF
52: Main body cover 53: Original table 54: Movable original table 55: Original stacking table 56: Pick-up motor 80: Pick-up roller 84: Paper feed belt 85: Separation roller 86: Pull-out driven roller 87: Pull-out drive roller 92: Reading exit Roller pair 93: Second reading exit roller pair 94: Paper ejection roller pair 95: Contact type image sensor 96: Second reading roller 98: Paper feed cover 150: Scanner 151: First side fixed reading unit 152: Moving reading unit 153 : Image reading sensor 154 : First contact glass 155 : Second contact glass 191 : Paper feed motor 192 : Conveyance motor 194 : Paper ejection clutch 201 : Sound collection microphone 901 : Main body control section 902 : Main body operation section 903 : Reading control section 904: Controller

Japanese Patent Application Publication No. 2021-181376

Claims (11)

a conveyance member that conveys the sheet;
a sound collection unit that collects operational sounds during sheet conveyance;
a feature amount extraction unit that extracts a feature amount of the operation sound collected by the sound collection unit;
A sheet conveyance apparatus comprising: a conveyance abnormality determination unit that determines whether or not a conveyance abnormality occurs based on the feature amount;
an index data selection unit that selects index data corresponding to the conveyance conditions of the sheet from a plurality of index data serving as an index for determining whether or not a conveyance abnormality occurs;
The sheet conveyance apparatus is characterized in that the conveyance abnormality determination section determines whether or not a conveyance abnormality occurs using the index data selected by the index data selection section. The sheet conveying device according to claim 1,
The sheet conveyance apparatus is characterized in that the sheet conveyance condition is the number of sheets being conveyed other than the sheet to be determined for conveyance abnormality. The sheet conveying device according to claim 2,
The sheet conveyance apparatus is characterized in that the sheet conveyance condition is whether or not there is a sheet being conveyed other than the sheet to be determined for conveyance abnormality. The sheet conveying device according to claim 1,
The sheet conveyance apparatus is characterized in that the sheet conveyance condition is a conveyance order of sheets to be determined for conveyance abnormality in a continuous sheet conveyance operation. The sheet conveying device according to claim 4,
In continuous sheet conveyance, control is performed to make the conveyance speed of the first conveyed sheet faster than the conveyance speed of the second and subsequent sheets,
The sheet conveyance apparatus is characterized in that the sheet conveyance condition is whether or not the sheet is conveyed first in the continuous sheet conveyance operation. The sheet conveying device according to claim 1,
A sheet conveyance device, wherein the sheet conveyance condition is a conveyance speed of the sheet. The sheet conveying device according to claim 1,
A sheet conveyance apparatus, wherein the conveyance abnormality determination section stops the sheet conveyance operation when the conveyance abnormality determining section determines that a conveyance abnormality has occurred. The sheet conveying device according to claim 1,
A sheet conveying device characterized in that the operating sound is an operating sound of a feeding roller that feeds sheets placed on a sheet tray. The sheet conveying device according to claim 1,
A sheet conveying device characterized in that the operation sound is a conveying sound of a sheet placed on a sheet tray being fed. Equipped with an original sheet transport section that transports original sheets,
In an automatic document conveyance device that conveys a document sheet to an image reading section by the document sheet conveyance section,
An automatic document conveyance device characterized in that the sheet conveyance device according to claim 1 is used as the document sheet conveyance section. In an image forming apparatus that forms an image on a sheet conveyed by a sheet conveyance section,
An image forming apparatus comprising the sheet transporting device according to claim 1 or the automatic document transporting device according to claim 9 as the sheet transporting section.

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