Image forming apparatus and abnormality determination method

Abstract

To improve determination accuracy of the presence or absence of a conveyance abnormality of a medium.SOLUTION: An image forming apparatus includes a conveyance unit for conveying a medium, a sound collection unit for collecting sound generated when conveying the medium, and a determination unit for determining the presence or absence of an abnormality related to the conveyance of the medium based on sound collected while the medium is conveyed in a predetermined section of a part of a route where the medium is conveyed.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to an image forming apparatus and an abnormality determination method. [Background technology]

[0002] When a document that cannot be transported normally, such as a stapled document, is set in an automatic document feeder (ADF) used in a copying machine or the like, an abnormal document transport such as a jam may occur.

[0003] In order to make it possible to determine the occurrence of such an abnormality, a method has been devised for determining whether or not a jam has occurred based on the sound generated when a movable member that is driven in relation to the transport of a medium is driven. In particular, the technology disclosed in Patent Document 1 is configured to determine whether or not a jam has occurred while a drive unit is driving the movable member using a different determination method from that used while the drive unit is not driving the movable member, in order to prevent erroneous determination of a jam occurring based on the sound. Summary of the Invention [Problem to be solved by the invention]

[0004] However, transport abnormalities are closely related to the position of the medium, and because the medium may slip during transport, the drive timing of the components that make up the ADF and the position of the medium are not necessarily consistent. Therefore, a method such as that in Patent Document 1 that determines whether a jam has occurred based on the drive timing of the movable components may result in an erroneous determination if the medium position is not as expected.

[0005] The present invention has been made in view of the above points, and has an object to improve the accuracy of determining whether or not there is a transport abnormality in a medium. [Means for solving the problem]

[0006] To solve the above problem, the image forming device has a transport unit that transports the medium, a sound collection unit that collects sound generated when the medium is transported, and a judgment unit that judges whether or not there is an abnormality in the transport of the medium based on the sound collected while the medium is being transported in a specified section of the path along which the medium is transported. [Effects of the Invention]

[0007] The accuracy of determining whether or not there is a transport abnormality in the medium can be improved. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram showing an example of a schematic configuration of a copying machine 100 according to an embodiment of the present invention. [Figure 2] FIG. 2 is a perspective view showing a scanner 150 and an ADF 51 of the copying machine 100. [Figure 3] 1 is an enlarged configuration diagram showing the main configuration of the ADF 51 together with the upper part of the scanner 150. FIG. [Figure 4] FIG. 2 is a diagram showing the appearance of the ADF 51. [Figure 5] 1 is a diagram showing an example of the configuration of a part of an electric circuit of a copying machine 100 according to an embodiment of the present invention. [Figure 6] 10 is a flowchart illustrating an example of a processing procedure executed by the copying machine 100. [Figure 7] FIG. 10 is a diagram showing an example of sound data during normal document transport. [Figure 8] FIG. 10 is a diagram showing an example of second sound data when an original is abnormally transported. DETAILED DESCRIPTION OF THE INVENTION

[0009] An embodiment of the present invention will be described below with reference to the drawings. In this embodiment, an electrophotographic copying machine (hereinafter referred to as "copying machine 100") will be described as an example of an image forming apparatus. For example, this embodiment can be applied to any image forming apparatus that has a transport unit for reading an image from a document, such as a scanner, a facsimile, or a multifunction machine. In this embodiment, a document is an example of a medium.

[0010] First, the basic configuration of a copying machine 100 will be described. Fig. 1 is a diagram showing an example of a schematic configuration of a copying machine 100 according to an embodiment of the present invention. In Fig. 1, the copying machine 100 includes an image forming unit 1, a sheet supply device 40, and an image reading system 50. The image reading system 50 includes a scanner 150 as an image reading device fixed above the image forming unit 1, and an automatic document feeder (hereinafter referred to as "ADF") 51 supported by the scanner 150.

[0011] The sheet supply device 40 has one or more paper feed cassettes, and conveys recording sheets set in the paper feed cassettes to the image forming unit 1.

[0012] The image forming unit 1 forms a toner image of black, yellow, magenta, and cyan (K, Y, M, C) from the image read from the original MS by the scanner 150, and fixes the toner image on a recording sheet transported from the sheet supply device 40.

[0013] Scanner 150, which is fixed on image forming unit 1, has a movable reading unit 152. Scanner 150 and ADF 51 each have a fixed reading unit. Mobile reading unit 152 is disposed directly below a second contact glass (not shown) fixed to the upper wall of the casing of scanner 150 so as to come into contact with document MS, and can move an optical system consisting of a light source, a reflecting mirror, etc., left and right in the figure. As the optical system moves from left to right in the figure, light emitted from the light source is reflected by a document (not shown) placed on the second contact glass, and then passes through multiple reflecting mirrors before being received by image reading sensor 153 fixed to the scanner body.

[0014] Meanwhile, the fixed reading unit is comprised of a first-side fixed reading unit 151 disposed inside the scanner 150 and a second-side fixed reading unit (not shown) disposed inside the ADF 51. The first-side fixed reading unit 151, which includes a light source, a reflecting mirror, an image reading sensor such as a CCD, and the like, is disposed directly below a first contact glass (not shown) fixed to the upper wall of the casing of the scanner 150 so as to come into contact with the original MS. When a sheet-like original MS transported by the ADF 51 (described later) passes over the first contact glass, light emitted from the light source is sequentially reflected by the original surface, passes through multiple reflecting mirrors, and is received by the image reading sensor. This allows the first side of the original MS to be scanned without moving the optical system consisting of the light source, reflecting mirrors, and the like. The second-side fixed reading unit scans the second side of the original MS after it has passed the first-side fixed reading unit 151.

[0015] The ADF 51, which is disposed on the scanner 150, includes a main body cover 52 and a document placement table 53, which serves as a document placement means for placing documents MS before scanning. The ADF 51 also includes a transport unit 54 for transporting the documents MS as sheet materials, and a document stack table 55 for stacking the scanned documents MS. As shown in FIG. 2, the ADF 51 is supported by a hinge 159 fixed to the scanner 150 so as to be able to swing up and down. The ADF 51 swings up and down like a door, exposing a first contact glass 154 and a second contact glass 155 on the top surface of the scanner 150 when open. In the case of single-sided bound documents, such as a book bound at one corner of a stack, the documents cannot be separated one by one, and therefore cannot be transported by the ADF. Therefore, in the case of single-sided bound documents, the ADF 51 is opened as shown in FIG. 2, and the single-sided bound document to be scanned is placed face down on the second contact glass 155, and the ADF is then closed. Then, the image of the page is read by the moving reading unit 152 of the scanner 150 shown in FIG.

[0016] On the other hand, in the case of a stack of multiple independent documents MS, the documents MS can be automatically transported one by one by the ADF 51, and the first-side fixed reading unit 151 in the scanner 150 and the second-side fixed reading unit in the ADF 51 can sequentially read the documents. In this case, the user places the document stack on the document placing table 53 and then presses the copy start button 158. The ADF 51 then feeds the documents MS of the document stack placed on the document placing table 53 into the transport unit 54 in order from the top, and transports them toward the document stack table 55 while inverting them. During this transport process, the documents MS are passed directly above the first-side fixed reading unit 151 of the scanner 150 immediately after being inverted. At this time, the image of the first side of the documents MS is read by the first-side fixed reading unit 151 of the scanner 150.

[0017] Fig. 3 is an enlarged configuration diagram showing the main configuration of the ADF 51 together with the upper part of the scanner 150. Fig. 4 is a diagram showing the external appearance of the ADF 51. The ADF 51 is equipped with a document setting section A, a separation feeding section B, a registration section C, a turning section D, a first reading conveyance section E, a second reading conveyance section F, a paper discharge section G, a stacking section H, etc. The ADF 51 also has a document conveyance path for conveying the document MS from the document placing table 53 toward the first-side fixed reading section 151, which is the image reading position.

[0018] The document setting unit A has a document placement table 53 on which a stack of documents MS is set. The separation and feeding unit B separates and feeds documents MS one by one from the set stack of documents MS. The registration unit C temporarily bumps against the fed documents MS, aligns them, and then sends them out. The turning unit D has a curved conveying section that curves in a C shape, and turns the documents MS upside down while folding them back within this curved conveying section. The first reading and conveying unit E conveys the documents MS on the first contact glass 154, and causes the first side of the documents MS to be read by the first-side fixed reading unit 151 disposed inside the scanner 150 below the first contact glass 154. The second reading and conveying unit F conveys the documents MS below the second-side fixed reading unit 95, and causes the second side of the documents MS to be read by the second-side fixed reading unit 95. The paper discharge section G discharges the document MS, the images of both sides of which have been read, toward the stack section H. The stack section H stacks the document MS on a document stack table 55.

[0019] The original MS is set with its leading edge placed on the movable original table 56, which can swing in the directions of arrows a and b in the figure depending on the thickness of the stack of originals MS, and its trailing edge placed on the original placement table 53. At this time, the side guides on the original placement table 53 are abutted against both ends of the original in the width direction (the direction perpendicular to the plane of the figure), thereby adjusting the position in the width direction. The original MS set in this manner pushes up a lever member 62, which is swingably disposed above the movable original table 56. Accordingly, the original set sensor 63 detects the setting of the original MS and transmits a detection signal to the controller of the ADF 51 (controller 904, described below). This detection signal is then sent from the controller of the ADF 51 (controller 904, described below) to the reading control unit of the scanner via the I / F.

[0020] A first length sensor 57 and a second length sensor 58, each consisting of a reflective photosensor or an actuator-type sensor, are held on the document placement table 53. These length sensors detect the length of the document MS in the transport direction.

[0021] Above the stack of originals MS placed on movable original table 56, there is disposed a pickup roller 80 that is supported by a cam mechanism so as to be movable in the vertical direction (the directions of arrows c and d in the figure). This cam mechanism is driven by a pickup motor to move pickup roller 80 up and down. When pickup roller 80 moves upward, movable original table 56 also swings in the direction of arrow a in the figure, and pickup roller 80 comes into contact with the uppermost original MS in the stack of originals MS. As movable original table 56 continues to rise, table rise detection sensor 59 eventually detects that movable original table 56 has reached its upper limit. This stops the pickup motor and stops the upward movement of movable original table 56.

[0022] The operator operates a main body operation unit, which is comprised of a numeric keypad, a display, etc., provided on the main body of copier 100, to set the reading mode, indicating whether it is a double-sided reading mode or a single-sided reading mode, and to press a copy start key. When the copy start key is pressed, a document feed signal is sent from a main body control unit (not shown) to a controller of ADF 51. Then, pickup roller 80 is rotated by the forward rotation of a paper feed motor (paper feed motor 191, described later), and the document MS on movable document table 56 is fed out from movable document table 56.

[0023] When setting the double-sided reading mode or single-sided reading mode, it is possible to collectively set double-sided or single-sided reading for all of the originals MS placed on the movable original table 56. It is also possible to set the reading mode individually for each individual original MS, for example, by setting the first and tenth originals MS to double-sided reading mode while setting the other originals MS to single-sided reading mode.

[0024] The document MS delivered by the pickup roller 80 enters the separation / feed section B and is delivered to a contact position with the paper feed belt 84. The paper feed belt 84 is stretched by a drive roller 82 and other components, and moves endlessly in the clockwise direction in the figure as the drive roller 82 rotates in accordance with the forward rotation of the paper feed motor. A separation roller 85, which is driven to rotate clockwise in the figure as the paper feed motor rotates in the forward direction, contacts the lower stretching surface of the paper feed belt 84. At the contact point, the surface of the paper feed belt 84 moves in the paper feed direction. In contrast, the separation roller 85 contacts the paper feed belt 84 with a predetermined pressure, and when the separation roller 85 is in direct contact with the paper feed belt 84 or when only one document MS is sandwiched in the contact area, the separation roller 85 rotates along with the belt or the document MS. However, when multiple documents MS are sandwiched in the contact area, the accompanying rotation force becomes lower than the torque of the torque limiter, and the separation roller 85 rotates clockwise in the figure, which is opposite to the accompanying rotation direction. As a result, the separation roller 85 applies a moving force in the opposite direction to the paper feeding to the documents MS below the top, and only the top document MS is separated from the several documents (hereinafter, the operation up to this point is referred to as the paper feeding / separation operation).

[0025] The leading edge of the document MS, which has been separated into a single sheet by the action of a separation unit such as the paper feed belt 84 and separation roller 85, is detected by a separation sensor 71 located downstream of the contact point between the paper feed belt 84 and separation roller 85. The separation sensor 71 may be located downstream of the contact point so that even if sound collection (conveyance abnormality determination) is initiated upon detection of the document MS, the collision sound generated by the document MS colliding with the separation unit is kept at a predetermined level and the collision sound is not picked up by the sound collection microphone 201. The document MS then enters the registration unit C. The leading edge is detected as the document passes directly below the abutment sensor 72. At this time, the pickup roller 80, which receives the driving force of the pickup motor, is still rotating. However, the downward movement of the movable document table 56 separates the document MS from the document MS, so that the document MS is transported solely by the endless movement force of the paper feed belt 84. The endless movement of the paper feed belt 84 continues for a predetermined time from the timing when the abutment sensor 72 detects the leading edge of the document MS. As a result, the leading edge of the document MS hits the contact portion between the pull-out drive roller 86 and the pull-out driven roller 87, which is driven to rotate while in contact with the pull-out drive roller 86. The position of the hit sensor 72 may be located before (upstream of) the contact portion to such an extent that the sound of the collision generated when the document MS hits the contact portion between the pull-out drive roller 86 and the pull-out driven roller 87 is not picked up by the sound collection microphone 201.

[0026] The pull-out driven roller 87 serves to transport the document MS to the pair of intermediate rollers 66 downstream in the document transport direction, and is driven to rotate by the reverse rotation of the paper feed motor. When the paper feed motor reverses, the pull-out driven roller 87 and one of the rollers of the pair of intermediate rollers 66 that are in contact with each other start to rotate, and the endless movement of the paper feed belt 84 stops. At this time, the rotation of the pickup roller 80 also stops.

[0027] The document MS sent out from the pull-out driven roller 87 passes directly below the document width sensor 73. The document width sensor 73 has multiple paper detection units, each consisting of a reflective photosensor or the like, which are aligned in the document width direction (the direction perpendicular to the plane of the drawing). The widthwise size of the document MS is detected based on which paper detection unit detects the document MS. 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 abutment sensor 72 to when the trailing edge of the document MS is no longer detected by the abutment sensor 72.

[0028] The leading edge of the document MS, whose widthwise size has been detected by the document width sensor 73, enters the turning section D and is sandwiched in the contact area between the rollers of the intermediate roller pair 66. The transport speed of the document MS by this intermediate roller pair 66 is set to be faster than the transport speed of the document MS in the first reading and transporting section E, which will be described later. This shortens the time it takes to send the document MS to the first reading and transporting section E.

[0029] The leading edge of the document MS being transported within the turning section D passes a position facing the reading entrance sensor 67. When the leading edge of the document MS is detected by the reading entrance sensor 67, the document transport speed by the intermediate roller pair 66 is reduced until the leading edge reaches the position of the reading entrance roller pair (pair of 89 and 90) on the downstream side in the transport direction. In addition, as the reading motor (not shown) starts to rotate, one roller of the reading entrance roller pair (89, 90), one roller of the reading exit roller pair 92, and one roller of the second reading exit roller pair 93 each start to rotate.

[0030] Within the turning section D, the document MS is reversed upside down and its conveying direction is reversed while it is conveyed along the curved conveying path between the pair of intermediate rollers 66 and the pair of reading entrance rollers (89, 90). Then, the leading edge of the document MS that has passed through the nip between the pair of reading entrance rollers (89, 90) passes directly below the registration sensor 65. Hereinafter, the operation up to this point after the paper feeding / separation operation is referred to as the pull-out operation.

[0031] When the leading edge of the document MS is detected by the registration sensor 65, the document transport speed is decelerated over a predetermined transport distance. Then, the transport motor (transport motor 192, described below) is stopped to stop the rotational drive of the pull-out drive roller 86 and the pair of intermediate rollers 66, and the reading motor (not shown) is stopped to stop the rotational drive of the pair of reading entrance rollers. As a result, the transport of the document MS is temporarily stopped at the registration position in front of the first reading transport unit E. In addition, a registration stop signal is sent to the reading control unit (not shown).

[0032] In this embodiment, a sound collection microphone 201 is further disposed at a position as shown in FIGS. 3 and 4. Specifically, the sound collection microphone 201 is disposed inside the paper feed cover 98, upstream of the separation mechanism constituted by the paper feed belt 84 and separation roller 85. This is because, when originals MS are bound with clips or staples, the topmost original MS attempts to be fed in the paper feed direction by the paper feed belt 84, but because it is fixed to the underlying originals MS by the binding, distortion occurs in the topmost original MS, and wrinkles or folds occur upstream of the paper feed belt 84. The sound collection microphone 201 is intended to be disposed near the position where these wrinkles or folds occur. The sound collection microphone 201 is disposed approximately in the center in the width direction (the direction perpendicular to the plane of the drawing). This is intended to place the sound collection microphone 201 at an average position where wrinkles or folds occur for originals MS of various widths.

[0033] 5 is a diagram showing an example of the configuration of a portion of the electrical circuitry of copier 100 according to an embodiment of the present invention. Main body control unit 901, which controls image forming unit 1, reading control unit 903, which controls scanner 150, and controller 904, which controls ADF 51, are each composed of a CPU, RAM, ROM, etc. Main body control unit 901 and reading control unit 903, reading control unit 903 and controller 904, and controller 904 and main body control unit 901 are each connected to one another and are capable of communicating with one another.

[0034] A transport motor 192 connected to the controller 904 is a rotational drive source for the pull-out drive roller 86 and the pair of paper discharge rollers 94 in the ADF 51. A pull-out clutch 193 connected to the controller 904 connects or disconnects the rotational drive force of the transport motor 192 to or from the pull-out drive roller 86. A paper discharge clutch 194 connects or disconnects the rotational drive force of the transport motor 192 to or from the pair of paper discharge rollers 94, which are the feed-out transport means.

[0035] Upon receiving the registration stop signal from the controller 904, the reading control unit 903 transmits a reading start signal, which is a paper feed permission signal, to the controller 904. The controller 904 then resumes rotation of the transport motor 192 and the reading motor. Then, at the timing when the leading edge of the original MS, calculated based on the pulse count of the reading motor, reaches the reading position by the first-side fixed reading unit 151, the controller 904 transmits a gate signal indicating the sub-scanning direction effective image area of ​​the first side of the original MS to the reading control unit 903. This transmission continues until the trailing edge of the original MS leaves 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.

[0036] After passing through the first reading conveyance unit E, the document MS passes through the reading exit roller pair 92, and then its leading edge is detected by the paper discharge sensor 61. When the single-sided reading mode is set, there is no need to read the second side of the document MS by the second-side fixed reading unit 95. Therefore, when the leading edge of the document MS is detected by the paper discharge sensor 61, the driving force of the conveyance motor is connected to the paper discharge roller pair 94 by the paper discharge clutch 194. Then, based on the paper discharge motor pulse count after the leading edge of the document MS is detected by the paper discharge sensor 61, the timing at which the trailing edge of the document MS will leave the nip of the paper discharge roller pair 94 is calculated. Then, based on the result of this calculation, the operation of the paper discharge clutch 194 is stopped.

[0037] On the other hand, when the double-sided reading mode is set, the timing from when the leading edge of the original MS is detected by the paper discharge sensor 61 until the original reaches the second-side fixed reading unit 95 is calculated based on the pulse count of the reading motor. Then, at that timing, the controller transmits a gate signal indicating the effective image area in the sub-scanning direction on the second side of the original MS to the reading control unit. This transmission continues until the trailing edge of the original MS leaves the reading position of the second-side fixed reading unit 95, and the second side of the original MS is read by the second-side fixed reading unit 95.

[0038] The second-side fixed reading unit 95 is composed of a contact image sensor (CIS), and its reading surface is coated to prevent vertical reading streaks caused by glue-like foreign matter adhering to the document MS adhering to the reading surface. A second reading roller 96 is disposed opposite the second-side fixed reading unit 95 as a document support means for supporting the document MS from the non-reading side. This second reading roller 96 prevents the document MS from floating at the reading position by the second-side fixed reading unit 95, and also functions as a reference white area for acquiring shading data in the second-side fixed reading unit 95.

[0039] The sound collecting microphone 201 is also connected to the controller 904. The sound information collected by the sound collecting microphone is converted into PCM data by an AD converter in the controller 904 and stored in RAM.

[0040] The following describes the processing procedure executed by the copier 100. Fig. 6 is a flowchart for explaining an example of the processing procedure executed by the copier 100.

[0041] When the copier 100 separates and feeds each document MS one by one from a stack of documents MS whose images are to be read and which are set on the document placing tray 53, the copier 100 performs processing for each document MS according to the processing procedure shown in FIG. 6. Note that in order to increase the reading throughput, the copier 100 continuously feeds the documents MS while leaving sufficient space between each document MS so that the documents do not overlap, and thus multiple documents MS are simultaneously present on the document transport path with a gap between them. Therefore, the processing procedure shown in FIG. 6 is executed in parallel for each document MS, leaving a gap between each document MS. The processing procedure shown in FIG. 6 is executed by the CPU of the controller 904 of the ADF 51 based on a program written in the ROM of the controller 904.

[0042] When the copy start key is pressed, a document feed signal is sent from the main body control unit 901 to the controller 904 of the ADF 51. The controller 904 then starts the aforementioned "document feed / separation operation." Specifically, the pickup roller 80 is rotated in the forward direction by the forward rotation of the document feed motor 191, and the document MS on the movable document table 56 is sent out from the movable document table 56 (S101).

[0043] Next, the controller 904 waits for a detection signal of the original MS from the separation sensor 71 (S102). When the detection signal of the original MS is received from the separation sensor 71, the controller 904 detects that the leading edge of the original MS has reached the position of the separation sensor 71 (YES in S102).

[0044] In response to the leading edge of the original MS reaching the position of the separation sensor 71, the controller 904 initializes a counter variable C to 0 (S103). As will be clear from the following description, the counter variable C is a variable used to detect abnormalities in the transport sound of the original MS (operation sound of the paper feeding / separation operation).

[0045] Next, the controller 904 captures the transport sound (sound signal) generated by the transport of the document MS, which is collected by the sound collection microphone 201, and records it in the RAM in the controller 904 (S104). This sound collection operation (collection and recording of the transport sound) is continuously executed in parallel with steps S105 to S109 until a transport abnormality is determined in step S108 or YES is determined in step S109.

[0046] Next, when a sound signal for a certain period of time (hereinafter referred to as "Ts") is newly recorded in RAM, the controller 904 calculates (extracts) the features of the sound signal for the immediately preceding Ts (S105). For example, the controller 904 performs a short-time Fourier transform (STFT) on the signal to obtain the power spectrum of the sound signal. Furthermore, to avoid the driving noise of the paper feed motor 191 (mainly 10 kHz or less), the controller 904 applies a high-pass filter to the obtained power spectrum to remove sound components below 12.5 kHz, and then calculates the average value of the sound intensity for all frequencies by averaging this on the frequency axis, and then performs decibel conversion to obtain the sound intensity level.

[0047] Next, the controller 904 determines whether the calculated sound intensity level exceeds a threshold value α (S106). The threshold value α may be set in advance based on, for example, experiments. If the sound intensity level does not exceed the threshold value α (NO in S106), the process proceeds to step S109. If the sound intensity level exceeds the threshold value α (YES in S106), the controller 904 adds 1 to C. Therefore, the number of times the sound intensity level exceeds the threshold value α for each time interval Ts is recorded in C.

[0048] Following step S107, the controller 904 determines whether or not there is a transport abnormality by comparing the value of the variable C with the threshold value β (S108). Specifically, if the value of the variable C is equal to or less than the threshold value β (YES in S108), the controller 904 determines that there is no transport abnormality and proceeds to step S109.

[0049] The controller 904 repeats step S104 and subsequent steps every Ts until the document MS is detected by the abutment sensor 72 (that is, until the leading edge of the document MS reaches the position of the abutment sensor 72) (S109).

[0050] If the document MS is detected by the abutment sensor 72 while the value of the variable C remains below the threshold value β (YES in S109), the controller 904 ends the loop processing from steps S104 to S109, controls the pull-out operation (S110), and controls the reading and discharging operation (S111).

[0051] If there is a next document MS (next page) (YES in S112), the controller 904 waits until the timing to start feeding the next document (S113), and then repeats step S101 and subsequent steps for the next document MS. If there is no next document MS (NO in S112), the controller 904 ends the processing procedure in FIG.

[0052] On the other hand, if the value of the variable C exceeds the threshold value β before the document MS is detected by the abutment sensor 72 (NO in S108), the controller 904 stops the transport operation at that point (S114).

[0053] Note that steps S104 (sound collection by sound collection microphone 201) and S105 (calculation of sound intensity level) may be started after step S101 (start of separation / paper feeding operation) and ended after YES in step S109. That is, sound collection microphone 201 may stop collecting sound when document MS is detected by bumping sensor 72. By stopping sound collection etc. together with stopping the determination of transport abnormalities, it is possible to suppress consumption of resources unnecessary for determining transport abnormalities.

[0054] As is clear from FIG. 6, the controller 904 counts the number of times that the time-series data or time sequence of sound intensity levels (hereinafter referred to as "sound data") for each time interval Ts exceeds a threshold value α. Examples of sound data are shown in FIGS. 7 and 8. FIGS. 7(A) and 7(B) show examples of sound data during normal document transport, with the degree of slippage of the document MS differing between (A) and (B). That is, the degree of slippage is greater in (B). FIG. 8 shows an example of sound data during abnormal document transport. In each figure, the horizontal axis corresponds to time, and the vertical axis corresponds to the sound intensity level. The threshold value α is also shown on the vertical axis. Furthermore, on the horizontal axis, t1 is the timing when the separation sensor 71 detects the leading edge of the document MS, and t2 is the timing when the abutment sensor 72 detects the leading edge of the document MS.

[0055] Even in the case of normal transport, when the original MS enters the area where the paper feed belt 84 and the separation roller 85 meet (hereinafter referred to as the "nip area"), the leading edge of the original MS is not necessarily transported straight into the nip area, but rather hits the paper feed belt 84 or the separation roller 85 as it enters the nip area. At this time, a collision sound is generated from the original MS. In the sound data shown in Figures 7(A) and 7(B), the area within the dashed ellipse s1 indicates this collision sound (hereinafter referred to as the "collision sound s1").

[0056] Skew correction is also performed when the original MS hits the contact point between the pull-out drive roller 86 and the pull-out driven roller 87. At this time, a collision sound is also generated from the original MS. In the sound data shown in Figures 7(A) and 7(B), the part enclosed by the solid ellipse s2 indicates this collision sound (hereinafter referred to as "collision sound s2").

[0057] For this reason, if counting up of variable C were to start based on sound data immediately after the start of the paper feeding / separation operation, the value of variable C would exceed threshold value β due to collision sound s1 even in the case of normal transport, and there is a possibility that abnormal transport would be erroneously detected despite normal transport. Also, since the leading edge position of original MS is not constant over time due to slippage during document transport and the entry of the next document due to accompanying feed during separation, if the period for counting up variable C (sound collection and judgment time) is made constant, there is a possibility that judgment will end even though the position of original MS is still in a position where sound collection and judgment are possible.

[0058] Therefore, in this embodiment, the presence or absence of an abnormality in the transport of the original MS is determined based on sounds collected while the original MS is being transported in a predetermined section of the path along which the original MS is transported. Here, the position at which the separation sensor 71 detects (the leading edge of) the original MS corresponds to the start position of the predetermined section (hereinafter referred to as the "determination start position"), and the position at which the abutment sensor 72 detects (the leading edge of) the original MS corresponds to the end position of the predetermined section (hereinafter referred to as the "determination end position"). In other words, the controller 904 starts determining whether or not there is a transport abnormality when the original MS reaches the determination start position, and ends the determination when the original MS reaches the determination end position.

[0059] The separation sensor 71, which is disposed at a determination start position beyond (downstream of) the nip portion, detects the leading edge of the document MS (YES in step S102), and then collects sound (step S104), calculates the sound intensity level (step S105), and determines whether or not there is a transport abnormality (step S106). This prevents the variable C from being counted up due to the collision sound s1, thereby preventing erroneous detection based on the collision sound s1. Furthermore, sound collection and determination of whether or not there is a transport abnormality are continued until the abutment sensor 72, which is disposed at a determination end position (a position before skew correction (inclination correction) is performed on the document MS) downstream of the separation sensor 71 and before (upstream of) the position where the pull-out drive roller 86 and the pull-out driven roller 87 come into contact, detects the document MS (S109). This avoids erroneous detection due to the collision sound s2, and allows sound of a necessary length to be collected and used for determination even when a document with a large slip is transported, thereby improving the accuracy of the determination.

[0060] 7(A) and 7(B), from (t1) when the original MS arrives at the separation sensor 71 (determination start position) until (t2) when the original MS arrives at the abutment sensor 72 (determination end position), the sound intensity level value does not exceed the threshold value α, so the value of variable C remains 0 (less than or equal to threshold value β), and it is determined that the transport is normal. On the other hand, in Fig. 8, from (t1) when the original MS arrives at the separation sensor 71 until (t2) when the original MS arrives at the abutment sensor 72, the value of variable C is counted up every time the sound intensity level exceeds threshold value α, and the value of variable C exceeds threshold value β before t2, so it is determined that the transport is abnormal (abnormal original).

[0061] As described above, according to this embodiment, the presence or absence of a transport abnormality (such as a jam) is determined based on the position of the original document MS, rather than the drive timing of the movable members of the ADF 51. Therefore, even if the time from the start of paper feeding until the leading edge of the original document MS reaches the contact point between the pull-out drive roller 86 and the pull-out driven roller 87 is not constant due to differences in the slip ratio of each original document, the presence or absence of a transport abnormality can be determined for all original documents based on the sounds collected in the same predetermined interval. As a result, the possibility of erroneous determination due to the collision sounds s1 and s2 can be reduced, and the accuracy of determining the presence or absence of a medium transport abnormality can be improved.

[0062] Each function of this embodiment can be realized by one or more processing circuits. Here, the term "processing circuit" in this specification includes a processor programmed to execute each function by software, such as a processor implemented by an electronic circuit, as well as devices such as an ASIC (Application Specific Integrated Circuit), a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), and a conventional circuit module designed to execute each function described above.

[0063] In this embodiment, the copier 100 is an example of an image forming apparatus. The ADF 51 (particularly the separation feeding unit B) is an example of a conveying unit. The sound collecting microphone 201 is an example of a sound collecting unit. The controller 904 is an example of a determining unit.

[0064] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and variations are possible within the scope of the gist of the present invention as described in the claims.

[0065] For example, aspects of the present invention are as follows.

[0066] <1> a transport unit that transports the medium; a sound collection unit that collects sounds generated when the medium is transported; a determination unit that determines whether or not there is an abnormality in the transport of the medium based on the sound collected while the medium is being transported in a predetermined section of a path along which the medium is transported; An image forming apparatus comprising:

[0067] <2> the determination unit starts determining whether or not there is an abnormality when the medium reaches a start position of the predetermined section, and ends the determination when the medium reaches an end position of the predetermined section. Characterized by <1> The image forming apparatus described above.

[0068] <3> the determination unit starts determining whether or not there is an abnormality when the sensor located at the start position detects the medium, and ends the determination when the sensor located at the end position detects the medium. Characterized by <2> The image forming apparatus described above.

[0069] <4> the sound collection unit stops collecting sound when the medium reaches an end position of the predetermined section. Characterized by <1> ~ <3> The image forming apparatus according to any one of the preceding claims.

[0070] <5> the determination unit determines the presence or absence of the abnormality based on time-series data of the sound intensity level at regular intervals. Characterized by <1> ~ <4> The image forming apparatus according to any one of the preceding claims.

[0071] <6> the determination unit determines whether or not the abnormality exists based on the number of times that the intensity level of the sound per fixed period of time exceeds a threshold value. Characterized by <5> The image forming apparatus described above.

[0072] <7> The medium is a medium from which an image is read. Characterized by <1> The image forming apparatus described above.

[0073] <8> a transport unit step of transporting the medium; a sound collection unit for collecting sounds generated when the medium is transported; a determination step of determining whether or not there is an abnormality in the transport of the medium based on the sound collected while the medium is being transported in a predetermined section of the path along which the medium is transported; The abnormality determination method is characterized in that the image forming apparatus executes the above. [Explanation of symbols]

[0074] 1 Image forming unit 40 Sheet feeding device 50 Image reading system 51 Automatic Document Feeder (ADF) 53 Document stand 54 Transport unit 56 Movable manuscript table 57 First length sensor 58 Second length sensor 61 Paper ejection sensor 63 Document set sensor 65 Resist Sensor 67 Reading entrance sensor 71 Separate Sensor 72 Push-button sensor 73 Document width sensor 100 copiers 150 scanner 151 First surface fixed reading unit 152 Mobile reading unit 153 Image reading sensor 154 First contact glass 155 Second contact glass 191 Paper feed motor 192 Transport motor 193 Pull-out clutch 194 Paper discharge clutch 201 Sound collection microphone 901 Main unit control unit 903 Reading control unit 904 Controller A Original setting area B Separation feeding section C Resist section D turn section E First reading and conveying section F Second reading and transport section G Paper output section H stack section [Prior art documents] [Patent documents]

[0075] [Patent Document 1] International Publication No. 2015 / 087453

Claims

1. a transport unit that transports the medium; a sound collection unit that collects sounds generated when the medium is transported; a determination unit that determines whether or not there is an abnormality in the transport of the medium based on the sound collected while the medium is being transported in a predetermined section of a path along which the medium is transported; An image forming apparatus comprising:

2. the determination unit starts determining whether or not there is an abnormality when the medium reaches a start position of the predetermined section, and ends the determination when the medium reaches an end position of the predetermined section.

2. The image forming apparatus according to claim 1, wherein:

3. the determination unit starts determining whether or not there is an abnormality when the sensor located at the start position detects the medium, and ends the determination when the sensor located at the end position detects the medium.

3. The image forming apparatus according to claim 2.

4. the sound collection unit stops collecting sound when the medium reaches an end position of the predetermined section.

2. The image forming apparatus according to claim 1, wherein:

5. the determination unit determines whether or not the abnormality exists based on time-series data of the intensity level of the sound at regular intervals.

2. The image forming apparatus according to claim 1, wherein:

6. the determination unit determines whether or not the abnormality exists based on the number of times that the intensity level of the sound per fixed period of time exceeds a threshold value.

6. The image forming apparatus according to claim 5.

7. The medium is a document from which an image is to be read.

2. The image forming apparatus according to claim 1, wherein:

8. a transport unit step of transporting the medium; a sound collection unit for collecting sounds generated when the medium is transported; a determination step of determining whether or not there is an abnormality in the transport of the medium based on the sound collected while the medium is being transported in a predetermined section of the path along which the medium is transported; The abnormality determination method is characterized in that the image forming apparatus executes the above.

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