Sheet conveying apparatus, sheet conveying method, and recording medium

Abstract

To highly accurately determine deterioration of a roller related to paper conveyance.SOLUTION: The first detector 18 of the sheet conveying device 10 is provided in the second extended area E2 obtained by extending, in the sheet-width direction, the area including the second area 12B on the downstream side of the center C of the nip area N of the pair of rollers in the conveying direction D and the area between the sheet feed roller E2 and the second area A2, in the orthogonally projected area obtained by orthogonally projecting the pair of rollers included in the separator 14 onto the conveying path R, and detects the sheet P conveyed on the conveying path R. The second detection unit 20 is provided downstream of the separation unit 14 in the transport path R in the transport direction D, and detects the sheet P transported along the transport path R. The determination part determines the deterioration of the roller 15 to be determined having the paper feeding roller 12B, the paper feeding roller 14A and the separation roller 14B based on a time difference between first detection timing of the paper P by the first detection part 18 and second detection timing of the paper P by the second detection part 20.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] An embodiment of the present invention relates to a paper transport device, a paper transport method, and a paper transport program. [Background technology]

[0002] The mechanisms for transporting paper in copiers, printers, and other devices use rollers made of materials such as rubber. As the number of sheets transported increases, these rollers experience deterioration, such as a decrease in friction, a decrease in diameter due to wear, and deterioration over time. This deterioration can lead to errors related to paper transport.

[0003] Therefore, a technology has been disclosed in which a sensor is installed downstream in the conveying direction of a roller to be judged for deterioration, and the deterioration of the roller is judged based on the time difference between the timing when paper conveyance begins and the timing when the sensor detects the paper. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5565018 Summary of the Invention [Problem to be solved by the invention]

[0005] However, with conventional technology, the accuracy of roller deterioration determination can be reduced due to disturbances such as misalignment of the leading edge of a sheet when a stack of sheets is set, or misalignment of the leading edge of subsequent sheets when the subsequent sheets are dragged along with the sheets during paper transport.

[0006] The problem to be solved by the present invention is to provide a paper transport device, a paper transport method, and a paper transport program that are capable of determining with high accuracy the deterioration of rollers involved in paper transport. [Means for solving the problem]

[0007] A paper transport device according to an embodiment includes a paper feed unit, a separation unit, a first detection unit, a second detection unit, and a determination unit. The paper feed unit includes a paper feed roller that feeds paper from a paper storage unit that stores paper to a transport path. The separation unit is located downstream of the paper feed unit in the transport path in the transport direction, includes a pair of rollers that sandwich and transport the paper, and separates and transports the paper fed from the paper feed unit one by one. The first detection unit is located in a second expanded region that is an orthographic projection region of the pair of rollers included in the separation unit, orthographically projected onto the transport path, and includes a second region downstream of the transport direction from the center of the nip region of the pair of rollers in the transport direction, and an area between the paper feed roller and the second region. The first detection unit is located in a second expanded region that is an expanded region in the paper width direction, including a second region downstream of the transport direction from the center of the nip region of the pair of rollers in the transport path, and detects the paper transported along the transport path. The second detection unit is located downstream of the separation unit in the transport path in the transport direction, and detects the paper transported along the transport path. The judgment unit judges deterioration of the paper feed roller and the roller to be judged, which includes the pair of rollers, based on the time difference between the first detection timing of the paper by the first detection unit and the second detection timing of the paper by the second detection unit. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is a schematic diagram of an example of a paper transport device according to an embodiment. [Figure 2A] Enlarged schematic diagram of the separation area. [Figure 2B] FIG. [Figure 3] FIG. 4 is a functional block diagram of a transport control unit. [Figure 4] 10 is a flowchart of the flow of information processing executed by a transport control unit. [Figure 5] FIG. 10 is a schematic diagram showing the relationship between transport time and frequency. [Figure 6] 6 is a diagram showing the relationship between the timing of detecting the leading edge position of a sheet of paper; [Figure 7] 10 is a diagram showing the measurement results of the relationship between the degree of deterioration of the roller to be evaluated and the normalized conveying time. [Figure 8A] An explanatory diagram of the ideal removal state. [Figure 8B] FIG. [Figure 9] Hardware configuration diagram. DETAILED DESCRIPTION OF THE INVENTION

[0009] The paper transport device, paper transport method, and paper transport program of the present embodiment will be described in detail below with reference to the accompanying drawings.

[0010] FIG. 1 is a schematic diagram of an example of a paper transport device 10 according to the present embodiment. The paper transport device 10 is a device that transports paper P along a transport path R. The paper transport device 10 is applied to a printer, a multifunction peripheral (MFP), etc. The following description will be given taking the case where the paper transport device 10 is a multifunction peripheral as an example.

[0011] The paper transport device 10 includes a paper feed section 12 , a separation section 14 , a transport section 16 , and a transport control section 22 .

[0012] The paper feed unit 12 includes a paper storage unit 12A and a paper feed roller 12B. The paper storage unit 12A is a storage unit that stores paper sheets P. The paper storage unit 12A is configured to be able to stack multiple sheets of paper P. The paper storage unit 12A may also be referred to as a paper feed tray or the like.

[0013] The paper feed roller 12B is a roller that feeds the paper P stored in the paper storage unit 12A to the transport path R. More specifically, the paper feed roller 12B comes into contact with the uppermost paper P among the multiple sheets of paper P stored in the paper storage unit 12A and sends it out to the transport path R by friction. The paper feed roller 12B is sometimes referred to as a pickup roller. The paper feed roller 12B is driven to rotate by a rotation drive motor (not shown). The rotation drive motor is driven and controlled by the transport control unit 22 (described later). The paper feed roller 12B is driven to rotate by the rotation drive motor to send out the paper P to the transport path R.

[0014] The paper sheet P sent to the transport path R is transported in the transport direction D by a plurality of rollers such as the separation unit 14 and the transport unit 16 arranged along the transport path R.

[0015] The separation unit 14 is provided downstream of the paper feed unit 12 in the transport direction D on the transport path R. The separation unit 14 is a mechanism that separates and transports the paper sheets P fed from the paper feed unit 12 one by one. The separation unit 14 includes a pair of rollers that sandwich and transport the paper sheets P. In this embodiment, a configuration will be described in which the separation unit 14 includes a paper feed roller 14A and a separation roller 14B as the pair of rollers.

[0016] The paper feed roller 14A is rotationally driven in a direction to transport the paper P downstream in the transport direction D. The paper feed roller 14A is rotationally driven by a rotation drive motor (not shown). The rotation drive motor is drive-controlled by a transport control unit 22 (described later).

[0017] Separation roller 14B is a driven roller with a torque limiter. When paper feed roller 14A and separation roller 14B are in direct contact with each other, and the frictional force between these rollers is greater than the torque limiter, separation roller 14B rotates following paper feed roller 14A. Following rotation is sometimes referred to as following rotation, rotation in synchronization, or synchronous rotation, etc.

[0018] When only one sheet of paper P enters the separation section 14, a conveying force is applied to the entering sheet P due to friction with the paper feed roller 14A, and the separation roller 14B creates frictional resistance. At the same time, a conveying force is applied to the separation roller 14B due to friction with the sheet P, and if the conveying force is equal to or greater than the torque limiter, the separation roller 14B rotates following the paper feed roller 14A via the sheet P.

[0019] More specifically, it is assumed that one sheet of paper P is present between paper feed roller 14A and separation roller 14B. In this state, paper feed roller 14A and paper feed roller 14B send paper P downstream in conveyance direction D. When the frictional force between paper P and separation roller 14B causes the rotational force in the direction sending paper P downstream in conveyance direction D to exceed the upper limit of the torque limiter, separation roller 14B rotates following paper feed roller 14A.

[0020] Now, let us consider a case where two or more sheets of paper P simultaneously enter the separation section 14. Because the coefficient of friction between sheets P is smaller than the coefficient of friction between sheets P and feed roller 12B, feed roller 14A, or separation roller 14B, slippage occurs somewhere between these multiple sheets of paper P. Therefore, the sheet P in contact with feed roller 14A is transported in conveyance direction D by feed roller 12B and feed roller 14A. Meanwhile, of the multiple sheets of paper P that have entered the separation section 14, the other sheets of paper P other than the sheet P in contact with feed roller 14A are not subjected to a conveyance force in conveyance direction D due to the ease of slippage between the sheets of paper P. Furthermore, because the other sheets of paper P are in contact with separation roller 14B, no conveyance force in conveyance direction D is applied due to friction with the sheet P in contact with feed roller 14A, and the other sheets of paper P are not conveyed in conveyance direction D. Furthermore, because the conveyance force is below the torque limiter, separation roller 14B does not rotate following feed roller 14A.

[0021] In this way, the separation unit 14 has two opposing actions: when there is one sheet of paper, the paper feed roller 14A transports the paper P downstream in the conveying direction D; and when there are multiple sheets of paper, the separation roller 14B prevents the following sheets of paper P from being transported downstream in the conveying direction D. Due to these opposing actions, when a sheet P is fed into the area (nip area N) where the paper feed roller 14A and the separation roller 14B are in contact, the paper P closest to the paper feed roller 14A is transported downstream in the conveying direction D, and sheets other than this paper P are prevented from being transported downstream in the conveying direction D. Therefore, when multiple sheets of paper P are transported overlapping each other and reach the separation unit 14, the multiple sheets of paper P are separated by the separation unit 14, and one sheet of paper P is transported downstream in the conveying direction D from the separation unit 14. In other words, the separation unit 14 has a function of preventing multiple sheets of paper P from being fed.

[0022] The conveying unit 16 is disposed downstream of the separating unit 14 in the conveying direction D. The conveying unit 16 conveys the paper P, which has been conveyed in the conveying direction D along the conveying path R via the separating unit 14 and has reached the conveying unit 16, further downstream in the conveying direction D. Note that, on the conveying path R, downstream of the conveying unit 16 in the conveying direction D, other conveying mechanisms, known image forming mechanisms that form images on the paper P, and the like may also be disposed.

[0023] The first detection unit 18 is provided in a second expanded area on the transport path R. Details of the second expanded area will be described later. The first detection unit 18 is connected to be able to communicate with a transport control unit 22, which will be described later. The first detection unit 18 is a sensor that detects the paper P transported on the transport path R.

[0024] The statement that the first detection unit 18 is provided in the second expanded region on the transport path R means that the detection position of the paper P by the first detection unit 18 is the second expanded region on the transport path R. Therefore, it is sufficient that at least the detection point that detects the paper P included in the first detection unit 18 is located in the second expanded region, and the main body part of the first detection unit 18 other than the detection point may be located at a position away from the transport path R, for example.

[0025] The first detection unit 18 may be a known sensor capable of detecting the paper P being transported along the transport path R. Examples of the first detection unit 18 include a sensor that detects the timing of the paper P passing by the paper P contacting a lever, a reflective sensor that reacts when the paper P is present within a certain distance on its optical axis, and a transmission sensor that turns on or off depending on whether the optical axes of the light receiving side and light emitting side are blocked.

[0026] The first detection unit 18 outputs a first detection signal, which is the detection result of the paper sheet P, to the transport control unit 22, which will be described later. In this embodiment, when the first detection unit 18 detects the paper sheet P, it outputs an ON signal as the first detection signal to the transport control unit 22. Furthermore, the first detection unit 18 continuously outputs the ON signal as the first detection signal to the transport control unit 22 while the paper sheet P is being detected. Furthermore, when the first detection unit 18 does not detect the paper sheet P or while the first detection unit 18 is not detecting the paper sheet P, it outputs an OFF signal as the first detection signal to the transport control unit 22.

[0027] Therefore, the timing at which the first detection signal output from the first detection unit 18 to the conveyance control unit 22 switches from an OFF signal to an ON signal is the timing at which the downstream end of the paper P in the conveyance direction D passes the detection position of the first detection unit 18 on the conveyance path R. Furthermore, the period during which the first detection signal output from the first detection unit 18 to the conveyance control unit 22 is an ON signal indicates the period during which the paper P continues to pass the detection position of the first detection unit 18. Furthermore, the timing at which the first detection signal output from the first detection unit 18 to the conveyance control unit 22 switches from an ON signal to an OFF signal is the timing at which the upstream end of the paper P in the conveyance direction D passes the detection position of the first detection unit 18 on the conveyance path R.

[0028] Fig. 2A is an enlarged schematic diagram of the vicinity of separation unit 14 in paper transport device 10. Fig. 2B is a top view of separation unit 14 viewed from the paper feed roller 14A side.

[0029] As described above, the first detector 18 is provided in the second expansion area A2 on the transport path R.

[0030] 2B, the second extended area A2 is an area obtained by extending in the paper width direction an area that includes the second area E2 of the orthographic projection area E and the area between the paper feed roller 12B and the second area E2.

[0031] The orthographic projection area E is an area where the paper feed roller 14A and the separation roller 14B are orthographically projected onto the transport path R. More specifically, the orthographic projection area E is an overlapping area between a first projection area where the paper feed roller 14A is orthographically projected onto the transport path R, and a second projection area where the separation roller 14B is orthographically projected onto the transport path R. Note that the orthographic projection area E may be the area on the transport path R that has a larger area than the first projection area or the second projection area, or the area that has a smaller area than the first projection area or the second projection area.

[0032] Specifically, the orthographic projection region E includes a first region E1 located upstream of a center C of the nip region N in the conveying direction D, and a second region E2 located downstream of the center C in the conveying direction D. The first region E1 is a region of the orthographic projection region E that is upstream of the center C of the nip region N between the pair of rollers (paper feed roller 14A, separation roller 14B) in the conveying direction D. The second region E2 is a region of the orthographic projection region E that is downstream of the center C of the nip region N between the pair of rollers (paper feed roller 14A, separation roller 14B) in the conveying direction D.

[0033] The paper width direction is the width direction of the paper P transported along the transport path R. The paper width direction coincides with the direction intersecting the transport direction D in a two-dimensional plane along the transport path R when the paper P is transported along the transport path R in the transport direction D.

[0034] The second extended area A2 is an area obtained by extending in the paper width direction an area including the second area E2 included in the orthographic projection area E and an area between the paper feed roller 12B and the second area E2.

[0035] Therefore, the second expansion area A2 includes the third expansion area A3 on the transport path R and an area on the transport path R between the third expansion area A3 and the paper feed roller 12B.

[0036] The third extended area A3 is an area obtained by extending the orthographic projection area E (first area E1, second area E2) in the paper width direction. That is, the third extended area A3 includes the first area E1, the second area E2, the third area E3, and the fourth area E4. The third area E3 is an area other than the first area E1 within the area obtained by extending the first area E1 in the paper width direction. The fourth area E4 is an area other than the second area E2 within the area obtained by extending the second area E2 in the paper width direction.

[0037] In other words, the second extended region A2 includes the second region E2, the fourth region E4, and the first extended region A1.

[0038] The first expanded region A1 is a region obtained by expanding in the paper width direction a region including the first region E1 and the region between the paper feed roller 12B and the first region E1. As shown in Fig. 2B, the first expanded region A1 includes the first region E1, the third region E3, and a region in the second expanded region A2 that is upstream of these regions (the first region E1 and the third region E3) in the conveying direction D.

[0039] The detection position of the first detection unit 18 is within the second expansion area A2, so that the first detection unit 18 can detect the paper sheet P that has been transported along the transport path R and has reached the second expansion area A2.

[0040] More specifically, the first detector 18 is preferably disposed in the first expansion area A1 within the second expansion area A2.

[0041] The detection position of the first detection unit 18 is within the first expansion area A1, so that the first detection unit 18 can detect the paper sheet P that has been transported along the transport path R and has reached the first expansion area A1.

[0042] More specifically, the first detector 18 is preferably disposed in a third expansion area A3 within the second expansion area A2.

[0043] The detection position of the first detection unit 18 is within the third expansion area A3, so that the first detection unit 18 can detect the paper sheet P that has been transported along the transport path R and has reached the third expansion area A3.

[0044] Returning to Figure 1, we continue the explanation.

[0045] The second detection unit 20 is provided downstream of the separation unit 14 on the conveying path R in the conveying direction D. The second detection unit 20 is connected so as to be able to communicate with the conveying control unit 22, which will be described later. The second detection unit 20 is a sensor that detects the paper P conveyed on the conveying path R. The fact that the second detection unit 20 is provided downstream of the separation unit 14 on the conveying path R in the conveying direction D means that the detection position of the paper P by the second detection unit 20 is downstream of the separation unit 14 on the conveying path R in the conveying direction D. For this reason, it is sufficient that at least the detection point included in the second detection unit 20 that detects the paper P is located downstream of the separation unit 14 on the conveying path R in the conveying direction D, and the main body part of the second detection unit 20 other than the detection point may be located at a position away from the conveying path R, for example.

[0046] In detail, it is preferable that the second detection unit 20 is provided on the conveying path R between the separation unit 14 and the conveying unit 16 which is provided downstream of the conveying path R from the separation unit 14 and includes conveying rollers 16A, 16B which convey the paper P.

[0047] Moreover, the second detection unit 20 is preferably disposed on the transport route R closer to the transport unit 16 than the midpoint between the separation unit 14 and the transport unit 16 .

[0048] The second detection unit 20 may be a known sensor capable of detecting the paper P being transported along the transport path R. Examples of the second detection unit 20 include a sensor that detects the timing of the paper P passing by the paper P contacting a lever, a reflective sensor that reacts when the paper P is present within a certain distance on its optical axis, and a transmission sensor that turns on or off depending on whether the optical axes of the light receiving side and light emitting side are blocked.

[0049] The second detection unit 20 outputs a second detection signal representing the detection result of the paper sheet P to the transport control unit 22. In this embodiment, when the second detection unit 20 detects the paper sheet P, it outputs an ON signal as the second detection signal to the transport control unit 22. Furthermore, the second detection unit 20 continuously outputs the ON signal as the second detection signal to the transport control unit 22 while the paper sheet P is being detected. Furthermore, when the second detection unit 20 does not detect the paper sheet P or while the paper sheet P is not being detected, it outputs an OFF signal as the second detection signal to the transport control unit 22.

[0050] Therefore, the timing at which the second detection signal output from the second detection unit 20 to the conveyance control unit 22 switches from an OFF signal to an ON signal is the timing at which the downstream end of the paper P in the conveyance direction D passes the detection position of the second detection unit 20 on the conveyance path R. Furthermore, the period during which the second detection signal output from the second detection unit 20 to the conveyance control unit 22 is an ON signal indicates the period during which the paper P continues to pass the detection position of the second detection unit 20. Furthermore, the timing at which the second detection signal output from the second detection unit 20 to the conveyance control unit 22 switches from an ON signal to an OFF signal is the timing at which the upstream end of the paper P in the conveyance direction D passes the detection position of the second detection unit 20 on the conveyance path R.

[0051] The positions of the first detection unit 18 and the second detection unit 20 in the direction intersecting the conveying direction D on the conveying path R are not limited. For example, the first detection unit 18 and the second detection unit 20 are preferably disposed in the center of the conveying path R in the direction intersecting the conveying direction D. By disposing the first detection unit 18 and the second detection unit 20 in the center of the intersecting direction on the conveying path R in the conveying direction D, it becomes possible to detect the sheet P even when the sheet P is conveyed at an angle on the conveying path R.

[0052] The first detection unit 18 may be disposed at both ends of the conveying path R in a direction intersecting with the conveying direction D. Similarly, the second detection unit 20 may be disposed at both ends of the conveying path R in a direction intersecting with the conveying direction D.

[0053] Next, we will explain the transport control unit 22. The transport control unit 22 controls the transport of paper P in the paper transport device 10. The transport control unit 22 is communicatively connected to the first detection unit 18, the second detection unit 20, the rotation drive motor and various motors provided in the paper transport device 10, the first detection unit 18, and the second detection unit 20.

[0054] FIG. 3 is a functional block diagram showing an example of the functional configuration of the transport control unit 22.

[0055] The transport control unit 22 includes a memory unit 24, a UI (user interface) unit 26, a communication unit 28, a drive unit 30, a detection unit 32, and a control unit 34. The memory unit 24, the UI unit 26, the communication unit 28, the drive unit 30, the detection unit 32, and the control unit 34 are communicatively connected via a bus or the like.

[0056] The storage unit 24 stores various types of data. The storage unit 24 may be provided outside the transport control unit 22. Furthermore, the storage unit 24 and at least one of one or more functional units included in the control unit 34 described below may be mounted on an external information processing device communicatively connected to the transport control unit 22 via a network or the like.

[0057] The UI unit 26 has a display function for displaying various information and an input function for receiving operation inputs from the user. The display function is, for example, a display, a projection device, etc. The input function is, for example, a pointing device such as a mouse or a touchpad, a keyboard, etc. The UI unit 26 may be a touch panel that integrates the display function and the input function.

[0058] The UI unit 26 may be configured to be communicably connected to the control unit 34 via a wired or wireless connection. The UI unit 26 may be configured to be provided outside the transport control unit 22, and the UI unit 26 and the control unit 34 may be connected via a network or the like.

[0059] The communication unit 28 is a communication interface for communicating with an external information processing device or the like of the transport control unit 22.

[0060] The drive unit 30 is a variety of drive mechanisms such as a rotary drive motor provided in the paper transport device 10.

[0061] The detection unit 32 is a variety of sensors provided in the paper transport device 10. The detection unit 32 includes a first detection unit 18 and a second detection unit 20.

[0062] The control unit 34 executes information processing in the transport control unit 22. The control unit 34 includes a drive control unit 34A, a detection result acquisition unit 34B, a determination unit 34C, and an output control unit 34D.

[0063] The drive control unit 34A, the detection result acquisition unit 34B, the determination unit 34C, and the output control unit 34D are realized, for example, by one or more processors. For example, each of the above units may be realized by having a processor such as a CPU (Central Processing Unit) execute a program, i.e., by software. Each of the above units may be realized by a processor such as a dedicated IC (Integrated Circuit) or circuit, i.e., by hardware. Each of the above units may be realized by a combination of software and hardware. When multiple processors are used, each processor may realize one of the units, or may realize two or more of the units.

[0064] The drive control unit 34A controls the drive unit 30, and controls various drive units 30 such as a rotation drive motor so that the paper P is transported along the transport path R of the paper transport device 10.

[0065] The detection result acquisition unit 34B acquires the detection results of the paper P from each of the first detection unit 18 and the second detection unit 20. In this embodiment, the detection result acquisition unit 34B acquires a first detection signal representing an ON signal or an OFF signal from the first detection unit 18. Furthermore, the detection result acquisition unit 34B acquires a second detection signal representing an ON signal or an OFF signal from the second detection unit 20.

[0066] The determination unit 34C determines the deterioration of the determination target roller 15 based on the time difference between the first detection timing of the paper P by the first detection unit 18 and the second detection timing of the paper P by the second detection unit 20.

[0067] The rollers to be judged for deterioration are rollers 15. In this embodiment, the rollers to be judged for deterioration include a paper feed roller 12B, a paper feed roller 14A, and a separation roller 14B, as shown in FIG.

[0068] The determination unit 34C calculates the time difference between the first detection timing of the paper P by the first detection unit 18 and the second detection timing of the paper P by the second detection unit 20. In detail, the determination unit 34C calculates the time difference between the first detection timing of the downstream end of the paper P in the transport direction D detected by the first detection unit 18 and the second detection timing of the downstream end of the paper P in the transport direction D detected by the second detection unit 20.

[0069] As described above, the timing when the first detection signal output from the first detection unit 18 to the conveyance control unit 22 switches from an OFF signal to an ON signal is the timing when the downstream end of the paper P in the conveyance direction D passes the detection position of the first detection unit 18 on the conveyance path R. Also, the timing when the second detection signal output from the second detection unit 20 to the conveyance control unit 22 switches from an OFF signal to an ON signal is the timing when the downstream end of the paper P in the conveyance direction D passes the detection position of the second detection unit 20 on the conveyance path R.

[0070] Therefore, the determination unit 34C determines the timing when the first detection signal received from the first detection unit 18 switches from an OFF signal to an ON signal as the first detection timing. The determination unit 34C also determines the timing when the second detection signal received from the second detection unit 20 switches from an OFF signal to an ON signal as the second detection timing.

[0071] Then, the determination unit 34C calculates the time difference between the first detection timing and the second detection timing.

[0072] The determination unit 34C determines the deterioration of the roller 15 to be determined by reading from the storage unit 24 the deterioration level information that indicates the degree of deterioration of the roller 15 to be determined that corresponds to the calculated time difference.

[0073] For example, the determination unit 34C associates the time difference with deterioration level information indicating the degree of deterioration of the roller 15 to be determined in advance and stores the information in the storage unit 24. The determination unit 34C then reads the deterioration level information corresponding to the calculated time difference from the storage unit 24 to determine the deterioration of the roller 15 to be determined.

[0074] Furthermore, the longer the time difference or the average value of the time difference over a certain period or a certain number of sheets, the greater the degree of deterioration that the judgment unit 34C may determine. Furthermore, the judgment unit 34C may determine that deterioration has occurred in the judgment target roller 15 when the time difference is equal to or greater than a threshold value.

[0075] In addition, the judgment unit 34C may judge a greater degree of deterioration when the proportion of the number of times that the time difference is determined to be greater than or equal to the threshold value to the total number of times that deterioration is determined based on the time difference during the period in which a predetermined number of sheets of paper P are transported is greater.

[0076] The determination unit 34C may also use the amount of change in the time difference as an index of deterioration. For example, the determination unit 34C may calculate an average value of the time difference for each predetermined number of sheets or each predetermined period. The determination unit 34C may then determine that the greater the amount of change in the calculated average value from the previously calculated average value, the greater the degree of deterioration.

[0077] The determination unit 34C may also use the variation in the time difference as an index of deterioration. This is because the greater the degree of deterioration of the roller 15 to be determined, the greater the variation in the time difference due to, for example, an increase in the number of slips. In this case, the determination unit 34C may determine a greater degree of deterioration as the variation in the time difference during the period in which a predetermined number of sheets P are transported increases.

[0078] Furthermore, in addition to the time difference, the determination unit 34C may determine that the greater the number of sheets that have passed through the sheet transport device 10, the higher the degree of deterioration. For example, the determination unit 34C may determine that the greater the number of sheets that have passed through or the greater the time difference, the higher the degree of deterioration.

[0079] Furthermore, the determination unit 34C may use a known method to train in advance a learning model that receives the time difference as input and outputs deterioration level information for the determination target roller 15. Then, the determination unit 34C may input the calculated time difference into the learning model, thereby acquiring deterioration level information as an output from the learning model, and use this as the determination result.

[0080] In addition, the judgment unit 34C judges that a group of multiple sheets of paper P has entered the separation unit 14 when the first detection unit 18 continues to detect the downstream end of the paper P in the conveying direction D even at the timing when the paper conveyance of the next paper P begins after the first detection unit 18 detects the downstream end of the paper P in the conveying direction D.

[0081] In detail, when the first detection signal received from the first detection unit 18 is an on signal and the on signal continues even when the time for paper transport of the next paper P arrives, the judgment unit 34C judges that a group of multiple sheets of paper P has entered the separation unit 14, that is, a multiple-taking state has occurred in the separation unit 14.

[0082] The output control unit 34D outputs the result of the determination made by the determination unit 34C regarding deterioration of the determination target roller 15. The output control unit 34D also outputs the result of the determination made by the determination unit 34C regarding the intrusion of a group of multiple sheets of paper P into the separation unit 14.

[0083] The output control unit 34D outputs the determination result by performing at least one of displaying the determination result on the UI unit 26, storing the determination result in the memory unit 24, and transmitting the determination result to an external information processing device via the communication unit 28. The external information processing device is, for example, a monitoring device or the like communicatively connected to the conveyance control unit 22 of one or more paper conveying devices 10 via a network or the like. The monitoring device may use the determination result of the deterioration of the roller 15 to be determined received from the paper conveying device 10 to transmit replacement instruction information indicating an instruction to replace the roller 15 to the information processing device or the like of the user in charge of the paper conveying device 10. The monitoring device may also distribute the determination result of the deterioration of the roller 15 to be determined of the paper conveying device 10 to the external information processing device.

[0084] Next, an example of the flow of information processing executed by the transport control unit 22 of the paper transport device 10 of this embodiment will be described.

[0085] FIG. 4 is a flowchart showing an example of the flow of information processing in which the transport control unit 22 of the paper transport device 10 of this embodiment executes a deterioration determination for one sheet of paper.

[0086] The drive control unit 34A controls the drive unit 30 and starts controlling various drive units 30 such as the rotation drive motor so that the paper P is transported along the transport path R (step S100). Also, in step S100, the current time is set as the timing to start transporting the paper P. The processing of step S100 starts supplying the paper P from the paper storage unit 12A to the transport path R and transporting the paper P along the transport path R.

[0087] The determination unit 34C determines whether the first detection signal received by the detection result acquisition unit 34B from the first detection unit 18 has switched from an OFF signal to an ON signal (step S102). If the determination in step S102 is affirmative (step S102: Yes), the process proceeds to step S104.

[0088] In step S104, the determination unit 34C sets the first detection timing T1 to the current time (step S104). The current time is the time for which a positive determination is made in step S102. If a past time has already been set for the first detection timing T1, the determination unit 34C overwrites the past time with the current time, thereby setting the first detection timing T1 to the current time.

[0089] Next, determination unit 34C determines whether the second detection signal received by detection result acquisition unit 34B from second detection unit 20 has switched from an OFF signal to an ON signal (step S106). Determination unit 34C repeats a negative determination (step S106: No) until a positive determination is made in step S106 (step S106: Yes). If a positive determination is made in step S106 (step S106: Yes), the process proceeds to step S108.

[0090] In step S108, the determination unit 34C sets the second detection timing T2 to the current time (step S108). The current time is the time for which a positive determination is made in step S106. If a past time has already been set for the second detection timing T2, the determination unit 34C overwrites the past time with the current time, thereby setting the second detection timing T2 to the current time.

[0091] Next, the determination unit 34C calculates the time difference between the first detection timing T1 and the second detection timing (step S110).Then, the determination unit 34C determines the deterioration of the determination target roller 15 based on the time difference calculated in step S110 (step S112).

[0092] The output control unit 34D outputs the determination result of step S112 (step S114), and ends this routine.

[0093] The deterioration of one sheet of paper is determined and the result is output according to the above process.

[0094] On the other hand, if a negative determination is made in step S102, the process proceeds to step S116. In step S116, the determination unit 34C determines whether the first detection signal detected by the first detection unit 18 continues to be an ON signal as at the time of the previous determination in step S102 (step S116).

[0095] If a negative determination is made in step S116 (step S116: No), the process returns to step S100. A negative determination is made in step S116 when the first detection signal detected by the first detection unit 18 is an OFF signal. If a positive determination is made in step S116 (step S116: Yes), the process proceeds to step S118.

[0096] In step S118, the determination unit 34C determines that a group of multiple sheets P has entered the separation unit 14, that is, that a multiple take-out state has occurred in the separation unit 14 (step S118). The output control unit 34D outputs the determination result of step S118 made by the determination unit 34C (step S120). Then, this routine ends.

[0097] As described above, paper transport device 10 of this embodiment includes paper feed unit 12, separation unit 14, first detection unit 18, second detection unit 20, and determination unit 34C. Paper feed unit 12 has paper feed roller 12B that feeds paper P from paper storage unit 12A, in which paper P is stored, to transport path R. Separation unit 14 is provided downstream of paper feed roller 12B in transport path R in transport direction D, and includes a pair of rollers (paper feed roller 14A, separation roller 14B) that sandwich and transport paper P. Separation unit 14 separates and transports paper P supplied from paper feed unit 12 one by one. The first detection unit 18 is provided in a second expanded region A2 obtained by expanding in the paper width direction a region including a second region E2 downstream in the conveying direction D from the center C of the nip region N of the pair of rollers in the orthogonal projection region of the pair of rollers included in the separation unit 14 onto the conveying path R, and a region between the paper feed roller 12B and the second region E2, within the orthogonal projection region obtained by orthogonally projecting the pair of rollers included in the separation unit 14 onto the conveying path R, and detects the paper P conveyed on the conveying path R. The second detection unit 20 is provided downstream in the conveying direction D from the separation unit 14 on the conveying path R, and detects the paper P conveyed on the conveying path R. The determination unit 34C determines deterioration of the determination target rollers 15, which include the paper feed roller 12B, the paper feed roller 14A, and the separation roller 14B, based on the time difference between the first detection timing of the paper P by the first detection unit 18 and the second detection timing of the paper P by the second detection unit 20.

[0098] In this way, the paper conveying device 10 of this embodiment determines the deterioration of the roller 15 to be judged based on the time difference between the first detection timing of the paper P by the first detection unit 18 provided in the second expansion area A2 and the second detection timing of the paper P by the second detection unit 20 provided downstream in the conveying direction D from the separation unit 14 on the conveying path R.

[0099] For this reason, paper transport device 10 of this embodiment can suppress a decrease in the accuracy of determining deterioration of roller 15 due to disturbances, etc., compared to conventional technology that determines deterioration of roller 15 based on the time difference between the start of transport of paper P and the detection of paper P by a sensor (second detection unit 20) located downstream of roller 15 in the transport direction D. Disturbances include misalignment of the leading edge of paper P when it is set in paper storage unit 12A, and misalignment of the leading edge of subsequent paper P when the following paper P is dragged along with the paper P during transport. The leading edge of paper P is the downstream end of paper P in the transport direction D.

[0100] Therefore, the paper transport device 10 of this embodiment can determine the deterioration of the rollers involved in paper transport with high accuracy.

[0101] The effects of the paper transport device 10 of this embodiment will be described in detail below.

[0102] In conventional technology, the conventional conveying time tends to gradually increase as the number of conveyed sheets increases. The causes of the conventional conveying time gradually increasing as the number of conveyed sheets increases include a decrease in the frictional force of the roller due to paper dust and dirt adhering to the roller surface, a decrease in the roller diameter due to wear, and an increase in the hardness of the rubber material due to aging. Therefore, even when using the conventional conveying time, it can be said that it is possible to predict the deterioration of the evaluation target roller 15 to some extent.

[0103] However, there is a large variation in the conventional transport time, which occurs due to reasons such as misalignment of the paper stack or paper P when set in paper storage unit 12A, or the conventional transport time for some paper sheets P being significantly shorter than that for other paper sheets P, etc.

[0104] The phenomenon in which the conventional transport time of some sheets of paper P is extremely short compared to other sheets of paper P is due to the leading edge position shift of the following sheets of paper P caused by the following sheets of paper P being dragged along when the following sheets of paper P are transported.

[0105] That is, in the conventional deterioration determination method using the transport time, the timing at which the transport of the paper P starts is subject to fluctuations caused by misalignment of the paper P due to external disturbances. For this reason, it is difficult to accurately determine the deterioration of the roller 15 to be determined using the conventional technology that determines the deterioration of the roller 15 to be determined using the time difference between the transport start timing and the second detection timing by the second detection unit 20, which is provided downstream of the separation unit 14 in the transport direction D.

[0106] Fig. 5 is a schematic diagram showing the relationship between transport time and frequency. In Fig. 5, the horizontal axis represents transport time and the vertical axis represents frequency. Diagram 42A is a diagram showing the frequency distribution of the occurrence frequency of each transport time, where transport time is the time difference between the first detection timing by first detection unit 18 and the second detection timing by second detection unit 20 in paper transport device 10 of this embodiment. Diagram 42B is a diagram showing the conventional transport time, which is the time difference between the transport start timing of paper P and the second detection timing by second detection unit 20, and the frequency distribution of the occurrence frequency of each transport time within that transport time.

[0107] As shown in conventional line 42B, a wide frequency distribution was obtained across a wide range of conveyance times, from short to long, for the conventional conveyance time. On the other hand, line 42A according to this embodiment showed a frequency distribution concentrated within a narrower conveyance time period than conventional line 42B. In other words, the time difference used in this embodiment can be said to be a time difference that suppresses the influence of disturbances and enables more accurate assessment of the deterioration of the target roller 15.

[0108] According to the paper transport device 10 of this embodiment, the time difference between the first detection timing by the first detection unit 18 arranged in the second expansion area A2 and the second detection timing by the second detection unit 20 provided downstream of the separation unit 14 in the transport direction D is used to determine deterioration of the evaluation target roller 15. By using this time difference to determine deterioration of the evaluation target roller 15, it can be said that the influence of external disturbances is suppressed and deterioration of the evaluation target roller 15 can be determined with high accuracy.

[0109] 6 is a diagram showing the relationship between the detection timing of the leading edge position of paper P transported along transport path R when first detection unit 18 is arranged in each of arrangements A, B, and C in paper transport device 10 of this embodiment. The leading edge position of paper has the same meaning as the leading edge of paper P described above, and is the end portion on the downstream side of paper P in transport direction D.

[0110] Arrangements A, B, and C are examples of arrangements of the first detection unit 18 in the paper transport device 10 of this embodiment. That is, arrangement A is within a first region E1, which is located upstream of the nip region N in the transport direction D, within the orthographic projection region E on the transport path R (FIG. 2B). Arrangement B is at the center of the nip region N. Arrangement C is within a second region E2, which is located downstream of the separation unit 14 on the transport path R in the transport direction D.

[0111] When the rubber roller is almost intact, the leading edge position of the paper P increases proportionally over time, as shown by line 46A. However, as the rubber roller deteriorates, the frictional force decreases, causing slippage and a decrease in the paper transport speed. While slippage can occur at any time, it is thought to be particularly likely to occur during the period before the leading edge of the paper P enters the separation section 14. When the paper P passes the center C of the nip area N, the transport forces of both the paper feed roller 12B and the paper feed roller 14A act on the paper, so the paper is expected to be transported almost normally. Furthermore, if the separation roller 14B has a built-in torque limiter, slippage occurs at a frictional force below the upper limit of the torque limiter. In other words, as shown by line 46B, it is expected that the transport speed of the paper P will be slowed or the paper will be stopped until the paper P reaches the center of the nip area N. The delay time is represented by t in FIG. 6.

[0112] That is, particularly when the first detector 18 is arranged in arrangement A, the time difference between the first detection timing by the first detector 18 and the second detection timing by the second detector 20 includes the delay time t, which is likely to occur during the period until the sheet reaches the center C of the nip region N due to slippage caused by roller deterioration, and the delay time t due to roller deterioration is likely to be reflected in the conveyance time. On the other hand, when the first detector 18 is arranged in arrangement B or arrangement C, the time difference between the first detection timing by the first detector 18 and the second detection timing by the second detector 20 does not include the delay time t shown in FIG. 6. However, the time difference does include a delay (not shown) caused by slippage or the like that occurs thereafter.

[0113] Therefore, in the paper conveying device 10 of this embodiment, when the first detection unit 18 is particularly positioned at position A, the conveying time includes a delay time t that is likely to occur upstream of the center C of the nip area N, so the degree of deterioration of the roller 15 to be judged can be determined with higher accuracy.

[0114] The delay time t is shorter when the degree of deterioration of the roller 15 to be evaluated is small. Therefore, the determination unit 34C may determine the degree of deterioration of the roller 15 to be evaluated by further using factors such as the difference between the time difference between the first detection timing and the second detection timing and the average value of this time difference, or whether the calculated time difference is within a range of abnormal values ​​measured in advance.

[0115] Fig. 7 is a graph showing the measurement results of the relationship between the degree of deterioration of the evaluation target roller 15 and the normalized conveying time. In Fig. 7, the horizontal axis represents the degree of deterioration of the evaluation target roller 15. In Fig. 7, the vertical axis represents the normalized conveying time.

[0116] Line diagram 48A and line diagram 48B are diagrams showing the relationship between the normalized transport time by sheet transport device 10 of this embodiment and the degree of deterioration of evaluation target roller 15. In detail, line diagram 48A is a diagram showing the relationship between the degree of deterioration of evaluation target roller 15 and the normalized transport time, where the transport time is the time difference between the first detection timing by first detection unit 18 arranged in first region E1 or third region E3 in Figure 2B and the second detection timing by second detection unit 20 provided downstream of separation unit 14 in the transport direction D.

[0117] Diagram 48B is a diagram illustrating a case where first detection unit 18 is disposed in second region E2 or fourth region E4 in Fig. 2B. In detail, diagram 48B is a diagram illustrating the relationship between the degree of deterioration of roller 15 to be evaluated and normalized conveyance time, where conveyance time is defined as the time difference between the first detection timing by first detection unit 18 and the second detection timing by second detection unit 20 provided downstream of separation unit 14 in conveyance direction D.

[0118] Diagram 48C is a diagram for the conventional technology. In detail, diagram 48C is a diagram showing the relationship between the degree of deterioration of roller 15 to be judged and normalized conveyance time, where conveyance time (conventional conveyance time) is defined as the time difference between the timing at which conveyance of sheet P begins and the timing of second detection by second detection unit 20, which is provided downstream of separation unit 14 in conveyance direction D.

[0119] As shown in line 48A of Figure 7, the relationship between the transport time and the degree of deterioration of the roller 15 to be evaluated when the first detection unit 18 is placed in the first region E1 or the third region E3 shows a higher correlation between the transport time and the degree of deterioration of the roller 15 to be evaluated than the conventional relationship between the transport time and the degree of deterioration represented by line 48C.

[0120] In line 48B, the first detection unit 18 is located in the second region E2 or the fourth region E4, and although line 48A is superior, it is possible to more accurately determine the deterioration of the evaluation target roller 15 compared to the conventional conveying time represented by line 48C. For this reason, it can be said that the paper conveying device 10 of this embodiment can determine the deterioration of the evaluation target roller 15 with high accuracy.

[0121] Furthermore, as described above, in the paper conveying device 10 of this embodiment, deterioration of the roller 15 to be judged is determined based on the time difference between the first detection timing of the downstream end of the paper P in the conveying direction D detected by the first detection unit 18 and the second detection timing of the downstream end of the paper P in the conveying direction D detected by the second detection unit 20.

[0122] By using the downstream end of the paper P in the conveying direction D as the first and second detection timings, it is possible to maintain an appropriate distance between the papers P being conveyed along the conveying path R regardless of the paper size of the paper P stored in the paper storage section 12A.

[0123] That is, in the paper transport device 10, it is necessary to adjust the transport timing of the paper P transported from the paper storage unit 12A to the transport path R after the paper P transported previously, depending on the state of the paper P transported previously. The paper sizes of the paper P stored in the paper storage unit 12A vary. The determination unit 34C uses the detection timing of the downstream end of the paper P in the transport direction D as the first detection timing and the second detection timing. Therefore, even if there is a delay in the transport of the paper P transported previously along the transport path R, the paper transport device 10 can appropriately maintain the distance between the upstream end (trailing end) in the transport direction D of the paper P transported previously and the downstream end (leading end) in the transport direction D of the paper P to be transported next, regardless of the paper size. This is because, depending on the product of the paper P, by the time the upstream end (trailing end) of the paper P in the transport direction D is detected, the downstream end (leading end) of the paper P in the transport direction D may have already progressed to the next process, causing interference with the paper P transported previously.

[0124] Furthermore, when the paper P stored in the paper storage unit 12A is sent from the paper storage unit 12A to the transport path R by the paper feed roller 12B, multiple sheets of paper P may be sent to the transport path R. However, by using the downstream end of the paper P in the transport direction D as the first detection timing and the second detection timing, it is possible to detect the downstream end (leading edge) in the transport direction D of the paper P that is transported ahead of one sheet of paper P, even when a subsequent sheet of paper P is transported following the previous sheet of paper P.

[0125] 8A and 8B are examples of diagrams for explaining the multiplexing state.

[0126] FIG. 8A is an explanatory diagram of an ideal removal state. More specifically, FIG. 8A is a diagram of an ideal state in which, when one sheet P arranged at the top of the multiple sheets P stored in sheet storage section 12A is transported to separation section 14, other sheets P scheduled to be transported following that sheet P are simply shown. The other sheets P will be referred to as subsequent sheets P. As shown in FIG. 8A, when the topmost sheet P in sheet storage section 12A is transported to separation section 14, the subsequent sheets P are not dragged by the topmost sheet P and do not move toward separation section 14, but are present on the side closer to sheet storage section 12A (sheet storage section 12A is not shown in FIG. 8A). In this case, the subsequent sheet P is detected by first detection section 18 after the transport start timing for that sheet P arrives.

[0127] 8B is a simplified diagram illustrating a state in which, when the topmost sheet P of multiple sheets P stored in sheet storage unit 12A is transported to separation unit 14, the subsequent sheets P are dragged by the previously transported sheets P, causing one or more subsequent sheets P to move toward separation unit 14. FIG. 8B illustrates a state in which a group of multiple sheets P enters separation unit 14 while misaligned in transport direction D. If the misalignment in transport direction D of multiple sheets P belonging to this group is less than a predetermined amount, determination unit 34C can calculate the time difference between the first detection timing by first detection unit 18 and the second detection timing by second detection unit 20 for one sheet P. However, if the misalignment in transport direction D of multiple sheets P belonging to this group is greater than or equal to the predetermined amount, a multiple-taking state occurs. The multiple feed state is a state in which a group of multiple sheets of paper P has entered the separation section 14, and is a state that is likely to lead to double feeding, in which the sheets are transported in an overlapping state through the nip area N between the paper feed roller 14A and the separation roller 14B. Furthermore, when a group of multiple sheets of paper P is transported through the nip area N while maintaining an overlapping state, the resistance increases, and therefore the time required to transport the group of sheets of paper P tends to increase.

[0128] Such a multiple-take state occurs due to slippage occurring at locations where the frictional force between sheets P in a group of multiple sheets P is reduced. Furthermore, a multiple-take state tends to occur more easily when control is performed to increase the applied load to maintain a constant frictional force on the sheet feed roller 12B. The frictional force of the sheet feed roller 12B is calculated by multiplying the friction coefficient and the applied load. When control is performed to increase the applied load to compensate for a decrease in the friction coefficient, the frictional force between the sheets P increases, making a multiple-take state more likely to occur. Therefore, a multiple-take state can be used as one indicator of a decrease in the frictional coefficient of the sheet feed roller 12B.

[0129] Therefore, in the paper transport device 10 of this embodiment, when the first detection signal received from the first detection unit 18 is an ON signal and the ON signal continues for a predetermined time or longer, the determination unit 34C determines that a group of multiple sheets P has entered the separation unit 14, i.e., that a multiple take state has occurred in the separation unit 14. By determining the multiple take state, the determination unit 34C can determine whether the paper feed roller 12B has deteriorated due to a decrease in the friction coefficient. Furthermore, when the determination unit 34C determines that a multiple take state has occurred, the determination unit 34C does not perform a deterioration determination of the roller 15 to be determined based on the time difference between the detection timing of the first detection signal and the detection timing of the second detection signal. This allows the determination unit 34C to suppress a decrease in the accuracy of deterioration determination.

[0130] Next, an example of the hardware configuration of the paper transport device 10 of the above embodiment will be described.

[0131] FIG. 9 is a diagram showing an example of the hardware configuration of the control unit 34 included in the paper transport device 10 of the above embodiment.

[0132] The paper conveying device 10 of the above embodiment is equipped with a control device such as a CPU (Central Processing Unit) 90D, a storage device such as a ROM (Read Only Memory) 90E, a RAM (Random Access Memory) 90F, and an HDD (Hard Disk Drive) 90G, an I / F section 90B that interfaces with various devices, an output section 90A that outputs various information, an input section 90C that accepts user operations, and a bus 90H that connects each section, and has a hardware configuration that utilizes a normal computer.

[0133] In the paper transport device 10 of the above embodiment, the CPU 90D reads out a program from the ROM 90E onto the RAM 90F and executes it, thereby realizing the above-mentioned respective units on the computer.

[0134] The programs for executing the above processes executed by the paper sheet transporting device 10 of the above embodiment may be stored in the HDD 90G. Also, the programs for executing the above processes executed by the paper sheet transporting device 10 of the above embodiment may be provided by being pre-installed in the ROM 90E.

[0135] Furthermore, the program for executing the above-described processes executed by the paper sheet transport device 10 of the above-described embodiment may be stored in an installable or executable file format on a computer-readable storage medium such as a CD-ROM, CD-R, memory card, DVD (Digital Versatile Disc), or flexible disk (FD) and provided as a computer program product. Furthermore, the program for executing the above-described processes executed by the paper sheet transport device 10 of the above-described embodiment may be stored on a computer connected to a network such as the Internet and provided by being downloaded via the network. Furthermore, the program for executing the above-described processes executed by the paper sheet transport device 10 of the above-described embodiment may be provided or distributed via a network such as the Internet.

[0136] Although the present embodiment has been described above, the above embodiment is presented as an example and is not intended to limit the scope of the invention. This novel embodiment can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. This embodiment and its modifications are included within the scope and spirit of the invention, and are also included in the inventions and their equivalents as defined in the claims. [Explanation of symbols]

[0137] 10 Paper transport device 12 Paper feed section 12A Paper storage section 12B Paper feed roller 14 Separation part 14A Paper feed roller 14B Separation roller 15 Judgment target roller 16 Conveyor 18 First detection unit 20 Second detection unit 22 Transport control section 34C Judgment part 34D Output control section

Claims

1. a paper feed unit having a paper feed roller that feeds paper from a paper storage unit in which paper is stored to a transport path; a separation unit that is provided downstream in the transport direction of the paper feed unit and includes a pair of rollers that sandwich and transport the paper, and that separates and transports the paper fed from the paper feed unit one sheet at a time; a first detection unit that is provided in a second expanded region that is expanded in a paper width direction to include a second region that is downstream in the conveying direction from a center of a nip region of the pair of rollers in the conveying direction and a region between the paper feed roller and the second region, within an orthogonal projection region that orthogonally projects the pair of rollers included in the separation unit onto the conveying path, and that detects the paper conveyed on the conveying path; a second detection unit provided on the transport path downstream of the separation unit in the transport direction, the second detection unit detecting the paper transported on the transport path; a determination unit that determines deterioration of the paper feed roller and a determination target roller that includes the pair of rollers based on a time difference between a first detection timing of the paper by the first detection unit and a second detection timing of the paper by the second detection unit; A paper transport device comprising:

2. The first detection unit 2. The paper transport device according to claim 1, wherein the orthogonal projection area includes a first area upstream in the transport direction from the center of the nip area of ​​the pair of rollers, and an area between the paper feed roller and the first area, and is arranged in a first expanded area expanded in the paper width direction.

3. The first detection unit The orthographic projection area is arranged in a third extended area obtained by extending the orthographic projection area in the paper width direction. The paper transport device according to claim 1 .

4. The second detection unit the conveying path is provided between the separation unit and a conveying unit that is provided downstream of the separation unit in the conveying direction and includes a conveying roller that conveys the paper; The paper transport device according to claim 1 .

5. The second detection unit The separating unit is disposed on the conveying unit side of the intermediate point between the separating unit and the conveying unit in the conveying path. The paper transport device according to claim 4.

6. The determination unit the first detection timing of the downstream end of the sheet in the transport direction detected by the first detection unit; and determining deterioration of the roller to be determined based on the time difference between the first detection timing and the second detection timing of the downstream end of the paper in the conveyance direction detected by the second detection unit. The paper transport device according to claim 1 .

7. an output control unit that outputs a determination result by the determination unit; The paper transport device according to claim 1 .

8. The determination unit When the first detection unit continues to detect the downstream end of the paper in the transport direction even at the timing when transport of the next paper starts after the first detection unit detects the downstream end of the paper in the transport direction, it is determined that a group of multiple sheets of the paper has entered the separation unit. The paper transport device according to claim 1 .

9. a separation unit provided downstream in the transport direction of the transport path from the paper feed unit, the separation unit including a pair of rollers that sandwich and transport the paper, and the separation unit separating and transporting the paper fed from the paper feed unit one by one; a first detection unit provided in a second expanded area obtained by expanding an area in the paper width direction of an orthogonal projection area of ​​the pair of rollers included in the separation unit onto the transport path, the second expanded area including a second area downstream in the transport direction from a center of a nip area of ​​the pair of rollers in the transport direction and an area between the paper feed roller and the second area, the first detection unit detecting the paper transported on the transport path; and a second detection unit provided downstream in the transport direction of the separation unit on the transport path, the second detection unit detecting the paper transported on the transport path, determining deterioration of the paper feed roller and the roller to be determined, the roller including the pair of rollers, based on a time difference between a first detection timing of the paper by the first detection unit and a second detection timing of the paper by the second detection unit; Paper transport method.

10. a separation unit provided downstream in the transport direction of the transport path from the paper feed unit and including a pair of rollers that sandwich and transport the paper, and that separates and transports the paper fed from the paper feed unit one by one; a first detection unit provided in a second expanded area in the paper width direction that expands an area that includes a second area downstream in the transport direction from a center of a nip area of ​​the pair of rollers in the transport direction downstream of the center of a nip area of ​​the pair of rollers and an area between the paper feed roller and the second area within an orthogonal projection area obtained by orthogonally projecting the pair of rollers included in the separation unit onto the transport path, and that detects the paper transported on the transport path; and a second detection unit provided downstream in the transport direction of the separation unit on the transport path and that detects the paper transported on the transport path. and executing a step of determining deterioration of the paper feed roller and a roller to be determined that includes the pair of rollers, based on a time difference between a first detection timing of the paper by the first detection unit and a second detection timing of the paper by the second detection unit. Paper transport program.

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