JP6360307B2 - Sheet feeding device, document feeding device, image reading device - Google Patents

Description

  The present invention relates to an automatic banknote depositing and dispensing machine installed in a bank or the like, and an automatic sheet handling apparatus that handles sheets such as an OCR (optical character reader) used in schools, hospitals, etc. The present invention relates to a sheet monitoring method and a conveyance mechanism for monitoring a conveyance state, for example, whether or not an abnormality has occurred in skew, double feeding, and an interval between sheets.

  In recent years, image forming apparatuses are provided with a plurality of functions that can be provided, and are becoming multifunctional. The functions include a copy function, a facsimile transmission function, a scan function, a print function, etc., and various types. Further, along with the diversification of the above functions, an automatic sheet feeding device (ADF) capable of automatically feeding sheets sequentially is also being installed.

  Here, in order to appropriately execute the above functions, it is indispensable that the sheets to be subjected to image formation are conveyed in the sheet conveyance path without being inclined obliquely.

  Normally, sheet conveyance of a sheet processing apparatus conveys a sheet by sandwiching the sheet between a driving roller and a driven roller biased by a spring or the like toward the driving roller, or between endless conveying belts. A method is used in which the sheet is held and conveyed.

  In such a sheet processing apparatus, one of the biggest problems is sheet jam. For example, when the sheet is inserted obliquely with respect to the sheet insertion opening, or when the sheet is conveyed obliquely due to imbalance of the pressing force of the belt or roller of the conveying means behind the sheet insertion opening, there is a problem of sheet jamming. Likely to happen.

  Also, if the sheet is conveyed in an inclined state (skewed state), the image may be read in an inclined state, or if the inclination is severe, the paper will be jammed in the conveyance path, causing damage to the sheet. May be. Regarding the problem of the conveyance performance, the same problem can occur regardless of the type of sheet being conveyed.

  As a conventional means for detecting the conveyance state of a sheet, there is an apparatus that detects a skew or a shift of a sheet by an image sensor, as in the apparatus described in Japanese Patent Application Laid-Open No. 2005-228561. Read the full width of the sheet conveyed by the image sensor provided on the conveyance path, binarize the output of the image sensor, create a data pattern in the longitudinal direction, and check the created data pattern Analyze whether it was conveyed in such a state.

  Further, as in the apparatus described in Patent Document 2, a transmissive light-emitting element and a light-receiving element are arranged side by side in a direction intersecting with the direction in which the sheet is conveyed, and light emitted from the light-emitting element is transmitted by the light guide. It is configured to enter the light receiving element across the conveyance path a plurality of times. During the period when the conveyed sheet blocks the light path between the light emitting element and the light receiving element, the light incident on the light receiving element is blocked, so it is possible to analyze the degree of inclination of the sheet by measuring the light blocking time. Become.

JP-A-6-183605 JP 2000-285278 A

  However, in the technique described in Patent Document 1, although it is possible to determine the skew state of the conveyed sheet from the image data read by the image sensor and detect a shift or skew, the image data read by the image sensor. Therefore, there is a problem that the processing load on the control unit becomes large.

  Further, since the conveyance state of the sheet is determined from the read image data, there is a problem that the detection of the skew state of the sheets and the paper jam is delayed, leading to the breakage of the sheet.

  Further, it is necessary to install an image sensor only for detecting the conveyance state of the sheet, and there is a problem that the area of the installation location is increased and the cost is increased.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to realize a sheet conveying apparatus that can more reliably prevent occurrence of a paper jam in a sheet with an inexpensive configuration.

Sheet feeding apparatus according to the present invention, the separating and feeding means for feeding separated from the sheet placing table sheets one by one, and the abnormality detecting means for detecting said that by the separating and feeding means feeding abnormalities The separation feeding area by the separation feeding means and the abnormality detection area by the abnormality detection means at least partially overlap each other, and the separation feeding means feeds the sheet while separating the sheets. It is possible to switch between feeding and non-separation feeding for feeding without separating sheets, and the abnormality detection means is configured to detect whether the separation feeding means performs the separation feeding and the non-separation feeding. In any case, skew or jam can be detected as a feeding abnormality, and the abnormality detecting means detects a feeding abnormality at the time of the separation feeding when the separation feeding means is switched to the separation feeding. Use the first threshold to determine When the separation feeding means is switched to the non-separation feeding, a threshold value different from the first threshold value and a feeding abnormality at the time of the non-separation feeding is determined. It is characterized by detecting a feeding abnormality using two threshold values.
The sheet feeding apparatus according to the present invention includes a separation feeding unit that separates and feeds sheets one by one from the sheet mounting table, and an abnormality detection region that detects a feeding abnormality by the separation feeding unit. An abnormality detection means formed by a plurality of sensor groups, and the abnormality detection area is at least partially overlapped with the separation feeding area by the separation feeding means in the sheet feeding direction, the separation feeding means, It is possible to switch between separation feeding for feeding sheets while separating them and non-separation feeding for feeding sheets without separating sheets, and the abnormality detection means is configured such that the separation feeding means is the separation feeding means. In both cases of feeding and non-separating feeding, skew or jam can be detected as feeding abnormality, and the abnormality detecting means is configured to switch the separation feeding means to the separated feeding. When separating feed When a feeding abnormality is detected using a first threshold value for determining feeding abnormality and the separation feeding unit is switched to the non-separating feeding, the non-separating feeding is different from the first threshold value. It is characterized in that a feeding abnormality is detected using a second threshold value for determining a feeding abnormality at the time of feeding.
The sheet feeding apparatus according to the present invention includes a separation feeding unit that separates and feeds sheets one by one from the sheet mounting table, and an abnormality detection region that detects a feeding abnormality by the separation feeding unit. An abnormality detection unit formed by a plurality of sensor groups, and a portion of the abnormality detection region on the upstream side in the sheet feeding direction includes a part of the separation feeding region by the separation feeding unit and the sheet feeding direction. The separation feeding means can be switched between separation feeding for feeding while separating sheets and non-separation feeding for feeding without separating sheets, and the abnormality detection means The separation feeding means can detect skew or jam as a feeding abnormality in any of the separated feeding and the non-separating feeding, and the abnormality detecting means is capable of detecting the separation feeding means. Switched to the separate feed When the separation feeding is detected by using the first threshold for determining the feeding abnormality at the time of the separation feeding, and the separation feeding unit is switched to the non-separation feeding, the first threshold It is characterized in that a feeding abnormality is detected by using a second threshold value that is a different threshold value and for determining a feeding abnormality at the time of the non-separated feeding.

  According to the present invention, it is possible to realize a sheet conveying apparatus that can more reliably prevent occurrence of a paper jam in a sheet with an inexpensive configuration.

1 is a front sectional view showing a schematic configuration of an image reading apparatus according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view showing a main part of the image reading apparatus shown in FIG. 1. FIG. 3 is a side view schematically showing a main part of a sheet separating mechanism of the sheet feeding apparatus 101. FIG. 3 is a top view schematically showing a main view of a sheet separating mechanism of the sheet feeding apparatus 101. The top view which shows roughly the separation mechanism main part and the arrangement | positioning area | region of a conveyance state detection means. The block diagram which shows the electric constitution of a conveying apparatus. The figure which showed the item which performs abnormality determination by a sheet conveyance defect determination means. FIG. 6 is a top view schematically showing how a sheet rotates when a staple document is fed. FIG. 6 is a top view schematically showing how a sheet rotates when a wide staple document is fed. The top view which showed a mode that the original document was hanging on S1R or S1L. FIG. 4 is a top view schematically showing a state in which a sheet is jammed by a separation roller pair. 6 is a flowchart of sheet conveyance state detection processing in the embodiment of the present invention. The top view which shows roughly the separation mechanism principal part of another form of this invention. The top view which shows roughly the separation mechanism principal part of another form of this invention. The top view which shows roughly the separation mechanism principal part of another form of this invention. The top view which shows roughly the separation mechanism principal part of another form of this invention. The figure which shows the positional relationship of the separation feeding area | region and abnormality detection area | region in other embodiment.

  The embodiment of the present invention has a feature in a mechanism for detecting an abnormality at the time of feeding a sheet, and in particular, an abnormality at the time of separating and feeding sheets one by one from a sheet mounting table. There is.

  Specifically, in the embodiment of the present invention, it comprises a separation feeding unit that separates and feeds sheets one by one from the sheet mounting table, and an abnormality detection unit that detects an abnormality during separation feeding, It is characterized in that the separation feeding area by the separation feeding means and the abnormality detection area by the abnormality detection means are at least partially overlapped.

  Here, it is preferable that the separation feeding area partially overlaps the upstream side of the abnormality detection area in the sheet feeding direction. Accordingly, it is possible to immediately detect an abnormal state of the sheet in the separation feeding area. Further, the abnormality detection region is preferably formed with an area substantially larger than the separation feeding region. This is because it is possible to accurately detect the state change of the sheet moving from the separation feeding area. Further, the abnormality detection area is preferably formed in an area extending outward from both ends of the separation feeding area in a direction orthogonal to the sheet feeding direction. Although details will be described later, for example, when the abnormality detection area is formed by arranging a plurality of sensors, the plurality of sensors can be arranged outside the separation feeding area. This is because it is possible to effectively prevent the separation and feeding configuration from interfering with each other. Also, by detecting an abnormality outside the separation feeding area and close to the separation feeding area, it is possible to immediately grasp the movement of the sheet during the separation feeding, thereby improving the abnormality detection accuracy. It becomes possible. That is, the abnormality detection accuracy can be increased by forming the abnormality detection region with a plurality of sensors so that the separation feeding region is included in the abnormality detection region.

  The abnormality detection area is an area for detecting a change in state such as an angle (tilt) in the sheet surface direction in the sheet feeding direction and a sheet feeding posture, and includes, for example, a plurality of sensor groups. That is, it can be formed by substantially surrounding the separation feeding region or its periphery by arranging a plurality of sensors. For example, if an optical sensor is used as a plurality of sensors, it is possible to prevent physical interference with the separation and feeding configuration and accurately grasp the change in the state of the sheet without contact.

  For example, the abnormality detection region may include a rectangular region formed by arranging a plurality of detection sensors facing each other in a direction orthogonal to the sheet feeding direction in the sheet feeding direction. Accordingly, it is possible to grasp the abnormal state of the sheet or a change in the state on a time axis at a plurality of locations in the sheet feeding direction.

  Further, the separation feeding area is an area including a portion where the separation feeding means using a separation pad, a separation roller, or the like is in contact with the sheet. When the separating and feeding means physically contacts the sheet, the sheet feeding posture may change. By detecting this change in the abnormality detection region, it is possible to respond quickly.

  Note that the separation feeding area includes at least a separation area for separating the sheet as a portion that physically contacts the sheet. In this separation region, the sheet is separated from the sheet bundle one by one by controlling the friction with the sheet, so that the traveling direction of the sheet may change during the separation process.

  In the embodiment of the present invention, when such a sheet traveling direction (posture in the feeding direction) changes, the abnormality detection region is separated and fed in order to quickly detect the state near the separation feeding unit. It is preferable to form the feeding region as a region from the portion where the separation feeding unit is in contact with the sheet to the downstream side in the sheet feeding direction.

  In the embodiment of the present invention, when the separation feeding area includes at least the roller structure, for example, a plurality of rollers (divided rollers) are mounted on the roller shaft, and the gap between the rollers is effectively made. Utilizing this, it is possible to arrange a plurality of sensors forming an abnormality detection region. In particular, in the case of a non-contact type sensor such as an optical sensor, an abnormality detection region can be formed corresponding to the gap between the rollers. As a result, it is possible to substantially form the abnormality detection region even in the separation feeding region. One abnormality detection area may be provided so as to surround one roller. For example, in the case where two rollers are mounted on one rotating shaft and the sheet is fed, an abnormality detection region may be provided so as to individually surround each roller. As another form, when adopting a comb-like roller provided with a plurality of grooves in the axial direction of the roller shaft with respect to the outer periphery of the roller instead of the divided roller, each of the gaps in the groove portion is used. Correspondingly, it is possible to substantially form the abnormality detection area in the separation feeding area by providing the detection area of the optical sensor and forming the abnormality detection area by the detection areas of the plurality of optical sensors. It becomes. Further, if the abnormality detection area is formed so as to extend to the outside of the separation feeding area while forming the abnormality detection area in the separation feeding area as described above, more effective abnormality detection can be realized. . In particular, according to the present invention, it is possible to realize an effective abnormality detection in a heterogeneous mixed sheet feeding in which sheets having different width dimensions are mixedly fed.

  Hereinafter, an embodiment of the present invention will be described more specifically with reference to the accompanying drawings.

  FIG. 1 is a schematic cross-sectional view for explaining an image reading apparatus including a sheet conveying apparatus (original feeding apparatus) according to an embodiment of the present invention. FIG. 2 is a schematic view of a main part of the image reading apparatus shown in FIG. FIG.

  As shown in FIGS. 1 and 2, the image reading apparatus 200 of the present embodiment includes a document table 1 on which a plurality of sheets F are stacked and driven up and down by a document table drive motor 2. On both sides of the document table 1 in the width direction of the sheet F, there are provided restriction plates 51 for restricting the skew of the sheet F in contact with both side portions of the sheet bundle stacked on the document table 1 in the width direction. The document detection sensor 3 detects the sheet F stacked on the document table 1. The pickup roller 4 sends out the sheets stacked on the document table 1 from the document table 1. The pickup motor 5 rotates the pickup roller 4.

  The feeding roller 6 is rotationally driven by a feeding motor 8 in a direction in which the sheet F is conveyed downstream. The separation roller 7 receives a rotational force for conveying the sheet F upstream from the separation motor 9 via a torque limiter (not shown). The feed motor 8 uses a stepping motor, and the motor rotates according to the number of input steps.

  When there is one sheet between the feeding roller 6 and the separation roller 7, the upper limit value of the rotational torque in the direction in which the torque limiter transmits the sheet back to the upstream side is transmitted to the separation roller 7. The rotational torque in the direction of feeding the sheet according to 6 downstream is higher. As a result, the separation roller 7 rotates following the feeding roller 6.

  On the other hand, when there are a plurality of sheets between the feeding roller 6 and the separation roller 7, the separation roller 7 holds the sheet back in the upstream direction to prevent entry other than the uppermost sheet.

  As described above, when a plurality of sheets are overlapped and fed to the nip portion 13 (FIG. 3) between the feeding roller 6 and the separation roller 7, the feeding roller 6 feeds the sheet downstream and the separation roller. 7 pushes the sheet back to the upstream side, so that only the uppermost sheet is fed to the downstream side. The sheets other than the uppermost sheet are returned to the upstream side, and the overlapping sheets are separated. Therefore, the feeding roller 6 and the separation roller 7 constitute a pair of separation rollers 42.

  In the present embodiment, the separation roller pair 42 is employed as the separation feeding unit. However, instead of the separation roller pair 42, a separation belt roller in which either the separation roller 7 or the feeding roller 6 is a belt. Pairs may be employed. Alternatively, a separation pad may be used in place of the separation roller 7.

  Further, the separation may be performed only by the torque limiter force without using the separation motor 9. The separation motor 9 is held so that the shaft does not rotate. In particular, for a thin sheet, separation by the return force of the torque limiter may be able to reduce jamming due to the folding of the leading edge of the sheet.

  The conveyance motor 10 drives a roller for conveying the separated and fed sheet from the sheet reading position to the discharge position. Further, the conveyance motor 10 drives the roller so that the sheet conveyance speed can be changed according to the optimum speed for reading the sheet, the resolution of the sheet, and the like.

  The image reading unit 43 includes reading sensors 14 and 15 that read a sheet image, and changes the scanning interval based on the reading speed and resolution of the sheet. The document discharge sensor 16 detects that the sheet has passed through the image reading unit 43 and is discharged to the discharge tray 44.

  The nip gap adjusting motor 11 adjusts a gap between the feeding roller 6 and the separation roller 7 or a pressure contact force with which the feeding roller 6 is pressed against the separation roller 7 via a sheet. As a result, the gap or pressure contact force suitable for the thickness of the sheet is adjusted, and the sheet can be separated and fed.

  The image reading unit 43 includes image reading sensors 14 and 15 that read sheet image information, and is controlled to change the line scanning interval based on the sheet reading speed and resolution settings. The image reading sensor 14 reads an image on the front side of the sheet, and the image reading sensor 15 reads an image on the back side of the sheet.

  The document transport roller pair 20, 21, the document transport roller pair 22, 23, and the downstream roller pair transport the document to the paper discharge tray 44. The upper guide plate 40 and the lower guide plate 41 guide the sheet conveyed by the separation roller pair 42, the registration roller pair 17, 18, the conveyance roller pair 20, 21, the conveyance roller pair 22, 23, and the downstream roller pair. To do.

  The pre-registration sensor 32 and the post-registration sensor 33 are sensors that detect the sheet conveyed on the conveyance path, and the conveyance of the sheet is controlled based on the sheet detection timing by these sensors.

  The conveyance state detection unit 60 is disposed in the vicinity of the feeding roller 6 and the separation roller 7 immediately after the sheet F is inserted into the conveyance path, and detects the conveyance state of the sheet F. When a sheet conveyance failure determination unit (not shown) determines that the conveyance is abnormal based on the detection result of the conveyance state detection unit 60, the control unit 45 controls to stop the sheet conveyance operation.

  When all the sheets are separated and fed, and when waiting for the sheets to be placed on the document table 1, the document table 1 is lowered, moved to the bottom of the driving range, and stopped. Then, the sheet is placed on the document table 1 and waits until an instruction to start the separation and feeding operation is given.

  The pre-registration sensor 32 is disposed on the upstream side of the registration roller pair 17 and 18, and detects the conveyed sheet. The post-registration sensor 33 is disposed on the downstream side of the registration roller pair 17 and 18, and detects the conveyed sheet.

  The control unit 45 controls the entire image reading apparatus 200 including the sheet conveying apparatus 101. For example, the motors are controlled based on output signals from sensors that detect the sheets, the rotation of the rollers is controlled, and the sheets are conveyed. Further, control is performed so as to read the image of the conveyed sheet.

  3 is a side view schematically showing the main part of the sheet separating mechanism of the sheet conveying apparatus 101 in FIG. 1, and FIG. 4 is a top view schematically showing the main part of the sheet separating mechanism of the sheet conveying apparatus 101. is there. FIG. 3 shows the positional relationship of the conveyance state detection means 60, the feeding roller 6, the separation roller 7, and the nip portion 13 where the feeding roller 6 and the separation roller 7 are in contact with each other. 4 shows the positional relationship between the document table 1, the sheet bundle F, the sheet F1, the pickup roller 4, the feeding roller 6, the separation roller 7, the conveyance state detection means 60, and the regulation plate 51.

  In the separation means in the sheet conveying mechanism configured as described above, the sheet is overlapped and fed by the action of the feeding roller 6 feeding the sheet downstream and the action of pushing the sheet of the separation roller 7 upstream. When the sheet is fed to the nip portion between the roller 6 and the separation roller 7, only the uppermost sheet is fed downstream.

  As the conveyance state detection means 60 shown in FIGS. 1 and 2, as shown in FIGS. 3 and 4, a sheet which is a non-contact optical sensor that detects the edge of the sheet in the conveyance direction around the separation roller pair 42. Detection sensors S1L, S1R, S2L, S2R, S3L, and S3R are arranged. The sheet detection sensors S1L, S2L, and S3L are arranged on the left side of the separation roller 7 at equal intervals in the sheet conveyance direction. Similarly, the sheet detection sensors S1R, S2R, and S3R are arranged at equal intervals in the sheet conveyance direction on the right side of the separation roller 7 (on the side opposite to the sheet detection sensor S1L). The sheet detection sensors S1R and S1L, the sheet detection sensors S2R and S2L, and the sheet detection sensors S3R and S3L are arranged apart from each other on the same line in the direction orthogonal to the conveyance direction.

  Among the sensors of the conveyance state detection means 60, the sheet detection sensors S1L and S1R on the most upstream side are arranged near the nip portion between the feeding roller 6 and the separation roller 7 as shown in FIG. A side view of the periphery of the feeding roller 6 and the separation roller 7 is shown in FIG. The feeding roller 6 receives a certain pressure from the separation roller 7 and bends between the rollers, and a contact area is a nip portion 13. When the sheet F is separated, the leading edge of the second sheet F from the upper side of the sheet F stays in the area of the nip portion 13 and only the uppermost sheet F1 is fed. If the sheet detection sensors S1L and S1R are present on the downstream side of the leading edge of the second sheet F when the feeding of the sheet F1 is finished, the timing at which the leading edge of the sheet passes when the sheet starts feeding. Can be detected. On the other hand, in order to detect a sheet abnormality earlier, it is necessary to dispose the sheet detection sensors S1L and S1R as upstream as possible. Therefore, the sheet detection sensors S1L and S1R are arranged on the boundary line on the downstream side of the nip portion 13 so as to satisfy both.

  The sheet detection sensors S2L, S2R, S3L, and S3R are arranged in the dotted line region shown in FIG. 5 so that the feeding abnormality can be detected before the separated sheet reaches the registration rollers 17 and 18. When the conveyance state detection unit 60 is disposed on the inner side in the sheet width direction with respect to the registration rollers 17 and 18, the sheet detection sensors S2L, S2R, S3L, and S3R are disposed on the upstream side of the registration rollers 17 and 18. When arranged outside the registration rollers 17 and 18, it may be arranged downstream of the registration rollers 17 and 18. This is because when the distance between the registration rollers 17 and 18 and the separation roller pair 42 is short, when the sheet is skewed, the front end of the sheet reaches the registration rollers 17 and 18 before the sheet hits the registration rollers 17 and 18. This is because it may precede the downstream side. In the arrangement area of FIG. 5, the sheet is widened toward the downstream side in the conveyance direction in consideration of the sheet skew.

  Next, a feeding abnormality determination method when the sheet detection sensors S1R, S1L, S2R, S2L, S3R, and S3L are used as the conveyance state detection unit 60 will be described.

  FIG. 6 is a diagram schematically showing an electrical block configuration of the sheet conveying apparatus of the present embodiment. In FIG. 6, the outputs of the sheet detection sensors S1L, S1R, S2L, S2R, S3L, and S3R are sent to the measuring unit 61, respectively. The measurement unit 61 calculates various types of conveyance information based on the output results of the sheet detection sensors S1L, S1R, S2L, S2R, S3L, and S3R, as will be described later. Information to be calculated includes sheet non-feed, skew, rotation, conveyance distance, and speed fluctuation. The transport information is sent to the comparator 62. The comparator 62 compares the sheet conveyance information measured by the measurement unit 61 with the reference value stored in the storage unit 12. As a result, when the normal condition cannot be satisfied, the sheet conveyance failure determination unit 64 determines that a conveyance abnormality has occurred, and sends an abnormality detection signal to the control unit 45. When receiving the abnormality detection signal, the control unit 45 stops the conveying unit and stops the conveyance of the sheet.

  Note that the timer counted by the measuring unit 61 may have a hardware configuration using a counter or a software configuration.

  Details of the conveyance information will be described below.

  First, the arrival timing of the sheet to the sheet detection sensors S1L, S1R, S2L, S2R, S3L, S3R and the pre-registration sensor 32 will be described. The arrival timing of the sheet is represented by a conveyance distance from the start of sheet feeding until the leading edge of the sheet reaches each sensor. The conveyance distance is expressed as tS1L, tS1R, tS2L, tS2R, tS3L, tS3R, and tBR in order for the sheet detection sensors S1L, S1R, S2L, S2R, S3R, and S3L and the pre-registration sensor 32, respectively. Since the feeding motor 8 uses a stepping motor, the transport distance is the number of steps input to the motor. When the feed motor 8 is always driven at a constant speed, the transport distance may be expressed not by the number of steps but by time. When feeding is started and the feeding motor 8 is driven, the number of steps of the motor is counted, and the same value is stored in tS1L, tS1R, tS2L, tS2R, tS3L, tS3R, and tBR as the conveyance distance of the sheet detection sensor. This process continues only for sensors that have not yet detected the leading edge of the sheet since the start of paper feeding. Thereby, the detection timing of the sheet | seat in each sensor position can be confirmed.

  Various sheet information is calculated based on the transport distance of each of these sensors, and it is determined whether there is a feeding abnormality. The items to be determined and the types of detection sections are as shown in FIG. FIG. 7 shows detection items to be determined, detection sections thereof, sensors used for detection in each detection section, comparison values calculated for determination, determination timing for determination, conditions for determining normal, determination Indicates the type of error to notify the user when the result is abnormal.

  Based on FIG. 6, each detection item is demonstrated concretely. In FIG. 6, from the arrangement of the sheet detection sensors S1L, S1R, S2L, S2R, S3L, and S3R in the transport direction, S1L and S1R are the first stage, S2L and S2R are the second stage, and S3L and S3R are the third stage. It is described as a sensor.

  First, non-feeding upstream of the separation will be described. The non-feeding upstream of the separation detects a state where the sheet cannot be fed because the sheet does not reach the separation roller pair 42 although feeding is started after the sheet is stacked on the document table 1. This detects that the sheet stacked on the document table 1 is removed and the sheet cannot be fed after the sheet feeding is started. The sheet detection sensor uses S1L and S1R in the first stage. If the sheet leading edge does not reach either S1L or S1R even if the sheet is transported and fed by the threshold TH0 after the start of feeding, it is determined that the sheet is not fed. The determination condition is that no feed is made if either tS1L ≦ TH0 or tS1R ≦ TH0 cannot be satisfied. If it is determined that the paper is not fed, the paper feeding is stopped, and a message indicating that there is no paper on the document table 1 is notified to the user.

  Next, skew will be described. In the skew feeding, a state in which the sheet is fed while being tilted more than a predetermined amount is detected. When the image reading start timing is determined based on the post-registration sensor 33, when the sheet is conveyed while being skewed, the leading edge and the trailing edge of the sheet are cut, and a portion that cannot be read occurs. In addition, the sheet corner may collide with the end of the conveyance path and the sheet may be damaged. In order to prevent these, skew is detected.

  One of the sheet detection sensors S1L, S2L, and S3L on the left side of the separation roller 7 and one of the sheet detection sensors S1R, S2R, and S3R on the right side, and a combination of these two, from the difference in detection timing. Calculate the skew amount. There are seven combinations in FIG. Of the seven patterns, there are three combinations in the direction orthogonal to the transport direction, which are combinations of S1L and S1R, S2L and S2R, and S3L and S3R. The skew amount is expressed as t11, t22, and t33, respectively. The absolute value of the threshold allowed as the skew feeding amount of the sheet is TH1. The comparison value is calculated by calculating the difference in detection timing so that the skew amount when the right end of the sheet precedes the downstream side becomes a positive value. When the left end of the sheet is skewed before the downstream side, the value is negative. The timing at which determination can be made is possible at any time after the start of feeding. The skew amount is 0 until the sheet is detected by one sensor, the skew amount is increased or decreased after the sheet is detected, and the skew amount is determined when two sheets are detected.

  Also, the remaining four skew amounts of the seven patterns in FIG. 7 are S1L and S2R, S2L and S3R, S2L and S1R, S3L and S2R as combinations of sensors tilted with respect to the sheet width direction. The skew amounts are expressed as t12, t23, t21, and t32. In these combinations, the distance between the sensors is increased in the transport direction, so that the amount of skewing increases as much. As a determination condition, an offset value A of the transport distance is added to correct the distance in the transport direction between the sensors. The absolute value of the upper limit and the lower limit of the allowable detection timing difference range varies depending on the offset. Therefore, the determination timing is after detection of one of the left and right sensors, and the determination condition is changed for each of the previously detected sensors.

  Next, rotation will be described. For the rotation of the sheet, the difference (rotation amount) of the skew amount is calculated for each detection section based on the already calculated seven skew amounts t11, t22, t33, t12, t23, t21, and t32. . There are four detection sections, between S1L / S1R and S2L / S2R, between S2L / S2R and S3L / S3R, between S1L / S2R and S2L / S3R, and between S2L / S1R and S3L / S2R. Each detection section is determined so that the straight lines connecting the left and right sheet detection sensors are parallel to each other.

  The sheet rotation detection is particularly effective when a sheet stopped with staples is conveyed. FIG. 8 shows the state of the sheet when the staple sheet is fed. FIG. 8A is a diagram when the leading edge of the staple sheet reaches the nip portion 13 of the separation roller pair 42. No skew has yet occurred at this stage. If the feeding is further continued, as shown in FIG. 8B, the first sheet of the staple sheet is slightly skewed, and the second sheet rotates in the opposite direction to the first sheet. Here, a slight skew is detected by the difference in sheet detection timing between S1L and S1R. When the sheet is further fed, as shown in FIG. 8C, the first sheet is further rotated, and it can be detected that the skew amount is increased in S2L and S2R.

  Depending on the surface state of the sheet and the size of the sheet, the sheet may be difficult to rotate. FIG. 9 is a diagram when a staple sheet wider than that in FIG. 8 is fed. In FIG. 9, the sheet is wrinkled near the staples as the staple sheet is fed, but the rotation of the sheet is delayed from FIG. 8 near the sheet detection sensor. When the leading edge of the staple sheet is at the point S1L / S1R (FIG. 9 (a)), there is almost no skew, but when it reaches S2L / S2R, the skew advances slightly (FIG. 9 (b)) and further proceeds. As shown in FIG. 9 (c). As described above, some staple sheets start skewing immediately after the separation nip portion as shown in FIG. 8, and some staple sheets increase skew after slightly progressing as shown in FIG. Therefore, it is effective to detect the skew feeding amount in a plurality of sections in the conveyance direction, not just after the nip portion, and to detect the rotation of the sheet.

  In addition, the sensor pair in the direction inclined with respect to the sheet width direction is also used, for example, as shown in FIGS. 10A and 10B, the sheet has already been detected in S1R or S1L at the start of feeding. In this case, since the sheet detection timing of these sensors is unknown, the abnormality cannot be determined. In this case, the detection section may be between S2L / S2R and S3L / S3R, but when S1R is detected, it is preferable to use a sensor on the upstream side as much as possible except S1R. In this case, the rotation of the sheet can be detected at an earlier stage when the interval between S1L / S2R and S2L / S3R is used. Moreover, it is also possible to detect more accurately by increasing the number of detection sections.

  In the determination condition for rotation, TH2 and TH3 are used as thresholds depending on the detection interval. TH2 is used in the detection section in which both of the most upstream sheet detection sensors S1L and S1R are used, and TH3 is used in other detection sections. The relationship between the two is TH2> TH3, and the upstream threshold is increased. This is to widen the allowable range of rotation in the upstream detection section and narrow the allowable range on the downstream side. Since the sheet detection sensor is arranged further downstream from the downstream boundary of the nip portion 13 of the pair of separation rollers 42, if there is no sheet skew, the feeding roller when the sheet is caught on the sheet detection sensors S1L and S1R 6 is stably fed. However, if the sheet is skewed before the start of feeding, the area where the sheet is sandwiched between the nip portions 13 is insufficient, and the leading edge may reach the sensor S1R or S1L while feeding is still unstable. . This is because the sheet feeding becomes unstable due to a difference in peripheral speed between the pickup roller 4 and the feeding roller 6 and friction when the leading edge of the skewed sheet comes into contact with the conveyance path. If the feeding is continued in this state, the skew amount is likely to change until the leading edge is stabilized, so the threshold value is increased in the upstream detection section. In addition, when the leading edge of the sheet exceeds the nip portion 13 and the feeding is stabilized, a change in the skew feeding amount other than an abnormal factor is reduced, so that the threshold value can be made smaller than that on the upstream side. Thus, by setting an optimum threshold value for each detection section, it is possible to accurately detect abnormal rotation of the sheet.

  Next, the conveyance distance will be described. The sheet conveyance distance is calculated in five detection sections as shown in FIG. Four of the five detection sections use the sheet detection sensors S1L, S2L, and S3L on the left side of the separation roller pair 42 and the sheet detection sensors S1R, S2R, and S3R on the right side. Calculate the transport distance at the tip. On the left side, first, the conveyance distance required for the leading edge of the sheet to move from S1L to S2L is calculated from the difference in sheet detection timing. Similarly, the above four transport distances are calculated from S2L to S3L, from S1R to S2R on the right side, and from S2R to S3R, and are represented by tL1, tL2, tR1, and tR2, respectively. These conveyance distances are determined to be abnormal if the sheet conveyance distance is extremely small with respect to the rotation distance of the roller when the feeding roller 6 is driven. TH4 is used as the threshold value.

  The fifth detection section of the conveyance distance can be detected when the pre-registration sensor 32 is arranged downstream of the sheet detection sensors S3L and S3R as shown in FIG. The conveyance distance in the section from the sheet detection sensors S3L, S3R to the pre-registration sensor 32 is calculated. The determination threshold is TH5.

  Next, speed fluctuation will be described. The sheet speed fluctuation is obtained by calculating the difference in the conveyance distance in each of the left and right detection sections of the separation roller pair 42 based on the already calculated four conveyance distances tL1, tL2, tR1, and tR2. This value is particularly effective in detecting abnormalities in thin paper. There are the following problems in separating and feeding thin paper. When feeding the thinnest uppermost sheet, the second and subsequent sheets are pushed in the conveying direction by friction with the first sheet being fed while the leading edge is stopped by the separation roller 7. This makes it easier to make wrinkles near the tip of the second and subsequent sheets. If many thin papers are separated while being in contact with the separation roller 7, the lower end of the stack of thin papers is pushed by the separation roller 7 every time the upper thin paper is fed. Expand. When the thin paper is fed as the uppermost paper, the leading edge is caught by the separation roller 7 or the conveyance path and conveyed. At this time, the moving speed of the leading edge of the thin paper is sent at a speed close to the feeding speed when it passes through the nip portion 13 of the separation roller pair 42, but it is caught immediately or clogged in the conveyance path itself, Movement speed is extremely reduced. At this time, as shown in FIG. 11B, the center of the sheet is jammed so as to be caught, so that the skew amount does not change much in many cases. In this case, it is possible to prevent the damage of the sheet from being expanded by detecting the speed fluctuation of the sheet. As a determination condition, an absolute value of an allowable speed fluctuation is TH6.

  Next, with reference to the flowchart shown in FIG. 12, a description will be given of the process of measuring the sheet inclination at the time when the sheet detection sensors S1L, S1R, S2L, S2R, S3L, and S3R have reached in such a configuration. Here, a flow for feeding one sheet will be described, but in actuality, this flow is continuously repeated to convey sheets one after another (S101).

  First, it is confirmed whether the sheet detection sensor can detect conveyance information in each detection section (S102). If a sensor has already detected a sheet before starting to feed the sheet, the detection timing of the sensor is unknown, so that conveyance information using the sensor is not calculated. In FIG. 7, the conveyance information including the sensor detecting the sheet in the “used sensor” column is not calculated, and the subsequent abnormality determination is not performed.

  Next, the paper feed step counter is cleared (S103). The paper feed step counter counts steps for driving the paper feed motor that is the basis of the transport distance. By clearing this counter at the start of paper feed, the number of drive steps of the paper feed motor from the start of paper feed can be determined. Then, after the count of the sheet feeding step counter is started (S104), the sheet feeding motor is driven (S105), and sheet feeding is started.

  In order to detect conveyance abnormality, it is necessary to memorize | store the conveyance distance in each sensor. Therefore, the transport distance is updated only for the sensor in the no paper state (S106). The conveyance distance detected by each sensor stores the value of the paper feed step counter. Since the transport distance of the sensor with paper is not updated, the value of the paper feed step counter when the leading edge of the sheet is detected is held for each sensor.

  Next, an item for comparing the value of the conveyance information for abnormality determination is determined (S107). Depending on the sensor or item used, calculation may be possible only after the sensor detects several sheets. If there is a paper detection condition in the “determination timing” in FIG. 7, the determination can be made only when the condition is satisfied. In addition, since it is not possible to determine items including the sensor that has detected the sheet at the start of feeding in step S102, it is excluded from the calculation target. Here, items that can be determined are stored. For this stored item, a comparison value used for abnormality determination is calculated for each conveyance information (S108). Here, the calculation is performed as shown in the column “comparison value” in FIG. It is determined whether the calculated item is abnormal (S109). As a result of the comparison, if all items are normal (S109-Yes), it is confirmed whether the trailing edge of the sheet has passed through the pre-registration sensor 32 (S110). When the trailing edge of the sheet passes through the pre-registration sensor 32, the feeding of one sheet is terminated (S111). If it cannot be finished yet (S110-No), S106, S107, S108, and S109 are repeated, and the sheet abnormality determination is repeated. If it is determined that there is an abnormality (S109-No), the paper feed motor is immediately stopped (S112) so that the sheet is not damaged. Subsequently, the occurrence of abnormality is notified to the user (S113). The content of the error to be notified is changed according to the detected item as described in the “notification error” column of FIG. Then, the process ends abnormally (S114).

  In step S109, when any one of the compared items is determined to be abnormal, the paper feeding abnormality is determined. However, a combination of a plurality of specific items may be a paper feeding abnormality. For example, for an error that reports skew, only the item whose detection interval is “third stage on the left and right” is used. The error to notify of jam is an error only when any of the total 6 items of rotation and speed fluctuation is abnormal and the item of “3rd left / right to pre-registration sensor” is abnormal in the transport distance. And In this determination method, an error determination can be made when the skew feeding amount is stable by using the sheet detection sensor in the downstream detection section for skew determination. Further, regarding the determination of jam, it can be detected that abnormality continues in a plurality of areas from the upstream side to the downstream side, so that it is suitable for determination of abnormality of a wide variety of paper types.

  Further, the user may select items to be determined in step S109.

  In the present embodiment, the sheet detection sensors S1L, S1R, S2L, S2R, S3L, and S3R are disposed in the vicinity of the separation roller pair 42. However, the sheet detection sensors S1L, S1R, S2L, S2R, S3L, and S3R are disposed. Is not limited to this arrangement.

  When the friction coefficient of the surface of the feeding roller 6 is high or when the pressing force to the feeding roller 6 by the separation roller 7 is strong, the sheet stopped by the staple may not be skewed in the vicinity of the separation roller 7. . The example has been described above with reference to FIG. If a sheet having a wide sheet width is often conveyed, the distance between the left and right sensors of the separation roller may be increased as shown in FIG. In this case, as shown in FIG. 13A, a region close to the stapled position can be detected, so that the rotation of the sheet is easily detected.

  Further, when the width of the sheet is increased, the conveyance distance at the sensor position when the sheet is rotated is also increased. In order to detect in a wider range, the interval in the transport direction may be widened as shown in FIG. Accordingly, rotation can be detected not only immediately after the separation nip but also in a wider range.

  Furthermore, the sensor may not be only a pair of left and right. As shown in FIG. 14, it is possible to cope with various sheet widths by arranging on both sides of a pair of left and right.

  In this embodiment, three sheet detection sensors are arranged side by side in the conveyance direction. However, the number may be two, or a large number may be arranged as shown in FIG. The cost can be reduced by using two. In addition, when a large number are arranged, the detectable region can be widened, so that the detection accuracy can be improved.

  Further, in the present embodiment, the sheet detection sensors are arranged in a line in the conveyance direction, but may be arranged at an angle inclined with respect to the conveyance direction as shown in FIG. In this case, various sheet widths can be accommodated with a smaller number of sensors.

  In the present embodiment, only TH1 is used as a threshold value for determining that the skew is abnormal. A different threshold may be used for each detection section. Similarly, the threshold values TH2 and TH3 are used for each detection section in the rotation, but more threshold values may be set. Similarly, the transport distance TH4 and the speed fluctuation TH6 may be set individually for each detection section.

  There is also a sheet feeding apparatus having a non-separation mode that does not separate sheets. In the non-separation mode, the connection from the separation motor 9 is cut to cause the separation roller 7 to idle, and the separation roller 7 is driven by the rotation of the feeding roller 6 to feed the sheet without separation while being bound. (Mode that does not transmit separation force to the sheet). The connection from the separation motor 9 to the separation roller 7 may be disconnected by an electromagnetic clutch, or may be switched manually by a user by providing a switching lever. This non-separation mode is used, for example, when it is desired to convey a half-folded sheet or a slip pasted with a plurality of sheets without separation. As a sheet pickup method, there are a method in which a sheet is stacked on the document table 1 and fed by the pickup roller 4 and a method in which the user manually inserts the feed roller 6 without using the pickup roller 4.

  In this non-separation mode, since the load applied to the sheet by the separation roller 7 is less than that in the separation mode in which the sheet is separated, damage to the sheet is reduced. However, in the non-separation mode, a sheet having a poor state is often conveyed, and a conveyance abnormality may occur around the separation and feeding region, so that it is necessary to detect the conveyance abnormality. Therefore, since the load on the sheet is small in the non-separation mode, various threshold values for determining an abnormality may be reduced to stop the conveyance more quickly. In the non-separation mode, the sheet is not separated, so that the rotation and speed fluctuation of the sheet hardly occur. Sheets that are in a bad state or half-folded sheets are stacked by hand, and when the sheet feeding starts, the sheet is released and the sheet may be fed, so that skewing of the sheet is likely to occur. Therefore, in the non-separation mode, the rotation and speed fluctuation thresholds may be decreased and the skew threshold may be increased.

  Further, in the configuration in which the nip pressure of the separation roller pair 42 can be changed, the nip pressure may be reduced when the sign of the sheet rotation is detected, and the sheet rotation may be easily caused. For example, when the skew of the sheet is detected by the upstream side S1R / S1L or the rotation is detected by S1R / S1L / S2R / S2L, the nip gap adjusting motor 11 is driven to reduce the nip pressure. If the amount of rotation or skew is greatly increased further downstream, it is determined that there is an abnormality and the sheet conveyance is stopped. If it is not judged abnormal, the nip pressure is returned to the original pressure. With this operation, the detection accuracy can be improved by causing the sheet to rotate quickly by the separation roller pair 42.

  In the above embodiment, the sheet conveyance handling apparatus that handles sheet-like paper such as OCR has been described. However, the present invention is not limited to this. The present invention can be similarly applied to a processing device for a deposit / withdrawal device to be handled, securities other than banknotes such as checks and stock certificates, or slips and postal items.

  Furthermore, the present invention can be applied to a so-called flat-type sheet conveying apparatus in which sheets are stacked with the sheet surface facing the sheet stacking tray surface as in the above-described embodiment, i.e., the embodiment described above, The present invention can also be applied to a so-called vertical-type sheet conveying apparatus that is placed on a sheet stacking tray surface with the thickness direction of the sheet bundle as a horizontal direction. In the latter case, for example, in a check scanner that reads a check sheet with magnetic ink characters (such as MICR characters) with a magnetic reading means disposed in the conveyance path, a check sheet bundle is taken one by one from the sheet stacking tray. When the separated feeding is performed and supplied to the conveyance path, the same effect as that of the above-described embodiment can be obtained by providing the abnormality detection area in the present invention so as to overlap the separated feeding area. In the magnetic reading means, if the check sheet is read with an inclination, the magnetic waveform may fluctuate and there is a risk of misreading (incorrect determination). However, it may be possible to improve the work efficiency by taking measures such as stopping the feeding by detecting before (or before), or improving the accuracy of the magnetic judgment by performing the magnetic judgment in consideration of the inclination of the check sheet. Also contributes.

  The sensor that detects the sheet conveyance state may be any sensor that can detect an end portion in the sheet conveyance direction. For example, an optical transmission sensor, an optical reflection sensor, a contact displacement detection sensor, paper quality, and the like may be used. A detectable media sensor, infrared sensor, or the like can be employed.

(Other embodiments)
In the above embodiment, the region surrounded by the feeding roller 6 and the separation roller 7 that are the separation feeding region and the abnormality detection regions S1L, S1R, S2L, S2R, S3L, S3R, and the pre-registration sensor 32 are shown in FIG. In the example shown in FIG. In this example, the overlapping area of the separation feeding area and the abnormality detection area is relatively small.

  However, in the present invention, as shown in FIGS. 17A and 17B, the separation feeding area and the abnormality detection area may be overlapped more greatly, or the abnormality detection area as shown in FIG. May be arranged so as to completely include the separation feeding area. By arranging the abnormality detection area in this way, it is possible to detect conveyance abnormality at an early stage before the sheet or document is separated and conveyed.

  In FIG. 17A, the abnormality detection region is arranged so that the upstream end of the abnormality detection region includes a region upstream of the separation feeding region. In this arrangement, for example, an unillustrated pickup roller located upstream of the feeding roller 6 and the separation roller 7 that are the separation feeding region is used to separate the document into the separation feeding region (the feeding roller 6 and the separation roller 6). When feeding the paper toward the separation roller 7), it is possible to detect the abnormality of the original document at an earlier stage (that is, between the feed roller 6 and the separation roller 7 and the pickup roller). This arrangement is particularly effective when the pressure applied to the original bundle by the pickup roller is weakened. For example, when the pressing pressure of the pickup roller is strong, the original bundle is more strongly fed into the separation feeding area, and after feeding the uppermost sheet of the original bundle, the top several sheets enter the separation feeding area. The probability of being higher. In this case, the movement of the leading edge of the document can be detected efficiently if the upstream end of the abnormality detection region is arranged downstream of the leading edge of the document. On the other hand, when the pressing pressure of the pick-up roller is weak, the force of feeding the top few originals of the original bundle into the separation feeding area is weak, and the leading ends of the upper few sheets are fed after feeding the topmost one of the original bundle. It is relatively frequent that the separation feeding area is not reached. In this case, it is better to arrange the abnormality detection area upstream of the separation feeding area.

  Further, when the leading edge of the document does not reach the separation feeding area, the document is fed only by the pickup roller, so that the document conveying force is weakened. If a contact-type sensor is used as a sensor used in the abnormality detection area, the conveyance of the original document is affected. However, if the optical sensor is used, the conveyance of the original document is not affected for abnormality detection. Therefore, when the optical sensor is used, the arrangement shown in FIG.

  Depending on the shape in the vicinity of the feeding port upstream of the separation feeding area and the arrangement of the pickup roller, the overlap between the separation feeding area and the abnormality detection area may be reduced as shown in FIG. . For example, in FIG. 3, in the vicinity of the feeding port on the upstream side of the separation roller 7, an inclined guide portion inclined toward the feeding port located at a relatively high position from the document placing surface is formed. The inclined separation of the guide portion substantially prevents a large number of document bundles from entering the separation nip portion 13 at the same time. In such a slope separation structure, when the document is skewed before feeding, the document receives a load from the slope, or when the document is climbing the slope, the leading edge of the document thrusts into the upper conveyance path, The skew of the document may be corrected slightly. In consideration of this point, sufficient abnormality detection can be performed by starting abnormality detection after the leading edge of the document reaches the separation feeding area. Therefore, the abnormality detection area is moved downstream from FIG. It may be arranged.

  The arrangement of FIG. 17A is effective even in the non-separation mode. As described above, the non-separation mode is a mode in which, for example, several sheet bundles bound with staples or the like, or half-fold sheets are fed without being separated. However, when the sheet bundle is fed toward the feeding roller 6 and the separation roller 7 by the pickup roller, particularly if the sheet bundle is thin paper with a low stiffness, the sheet bundle is caused by friction between the sheet and the document table. The image is fed obliquely, and the shape of the document becomes abnormal in the read image. In order to prevent this, it is preferable to detect the skew of the sheet before the leading end of the sheet enters the nip portion 13 formed by the feeding roller 6 and the separation roller 7. In such a case, FIG. The arrangement of a) is effective.

DESCRIPTION OF SYMBOLS 1 Original platen 2 Original platen drive motor S1R, S1L, S2R, S2L, S3R, S3L Sheet detection sensor F Original (sheet)
F1 Uppermost sheet of sheet bundle 3 Sheet detection sensor (original platen)
4 Pickup Roller 5 Pickup Motor 6 Feeding Roller 7 Separating Roller 8 Feeding Motor 9 Separating Motor 10 Carrying Motor 11 Nip Clearance Adjusting Motor 12 Storage Unit 13 Nip Portions 14 and 15 Image Reading Sensors 17 and 18 Registration Roller 19 Registration Clutch 20 21 Document transport roller (sheet supply transport means)
22, 24 Document conveying roller (sheet discharge conveying means)
26 Discharged driven roller 27 Conveyor roller 28 Discharge motor 32 Pre-registration sensor 33 Post-registration sensor 40 Upper guide plate 41 Lower guide plate 42 Separating roller pair 43 Image reading unit 44 Discharge tray 45 Control unit 51 Restriction plate 60 Conveyance state detection Means 101 Sheet conveying device 200 Image reading devices tS1L, tS1R, tS2L, tS2R, tS3L, tS3R

Claims (22)

Separation feeding means for separating and feeding sheets one by one from the sheet mounting table;
And an abnormality detecting means for detecting the feeding abnormality that by the separation feeding means,
The separation feeding area by the separation feeding means and the abnormality detection area by the abnormality detection means at least partially overlap,
The separation feeding means can be executed by switching between separation feeding for feeding while separating sheets and non-separation feeding for feeding without separating sheets,
The abnormality detecting means can detect skew or jam as a feeding abnormality in any case where the separation feeding means is either the separation feeding or the non-separation feeding,
The abnormality detection unit detects a feeding abnormality using a first threshold value for determining a feeding abnormality at the time of the separation feeding when the separation feeding unit is switched to the separation feeding, and the separation When the feeding means is switched to the non-separated feeding, a feeding abnormality is detected by using a second threshold value that is different from the first threshold value and for determining a feeding abnormality during the non-separating feeding. A sheet feeding apparatus characterized by: The separating and feeding means includes a roller that is rotated by a rotationally driven motor and feeds a sheet,
The sheet feeding apparatus according to claim 1, wherein a downstream side in the sheet feeding direction of the separation feeding area and an upstream side in the sheet feeding direction of the abnormality detection area partially overlap each other. The jam is detected based on any abnormality of sheet rotation, feeding distance, and speed fluctuation,
The sheet feeding apparatus according to claim 1, wherein the abnormality detection area is surrounded by a plurality of sensor groups.   The abnormality detection region includes a rectangular region formed by arranging a plurality of detection sensors facing each other in a direction orthogonal to the sheet feeding direction in the sheet feeding direction. The sheet feeding apparatus according to any one of the above.   The sheet feeding apparatus according to claim 1, wherein the separation feeding region includes a portion where the separation feeding unit is in contact with the sheet.   The sheet feeding apparatus according to claim 1, wherein the separation feeding region includes at least a separation region for separating sheets.   2. The abnormality detection area is formed as an area from the part where the separation feeding unit is in contact with the sheet to the downstream side in the sheet feeding direction in the separation feeding area. The sheet feeding apparatus according to any one of claims 1 to 6.   The sheet feeding apparatus according to claim 1, wherein the abnormality detection region is formed with an area substantially larger than the separation feeding region.   9. The abnormality detection area according to claim 1, wherein the abnormality detection area is formed by an area extending outward from both ends of the separation feeding area in a direction orthogonal to the sheet feeding direction. The sheet feeding apparatus described in 1. Separation feeding means for separating and feeding sheets one by one from the sheet mounting table;
And an abnormality detection means for forming abnormality detection area for detecting a feeding abnormality that by the separation feeding means in a plurality of sensors,
The abnormality detection area is at least partially overlapped with the separation feeding area by the separation feeding means in the sheet feeding direction,
The separation feeding means can be executed by switching between separation feeding for feeding while separating sheets and non-separation feeding for feeding without separating sheets,
The abnormality detecting means can detect skew or jam as a feeding abnormality in any case where the separation feeding means is either the separation feeding or the non-separation feeding,
The abnormality detection unit detects a feeding abnormality using a first threshold value for determining a feeding abnormality at the time of the separation feeding when the separation feeding unit is switched to the separation feeding, and the separation When the feeding means is switched to the non-separated feeding, a feeding abnormality is detected by using a second threshold value that is different from the first threshold value and for determining a feeding abnormality during the non-separating feeding. A sheet feeding apparatus characterized by: Separation feeding means for separating and feeding sheets one by one from the sheet mounting table;
And an abnormality detection means for forming abnormality detection area for detecting a feeding abnormality that by the separation feeding means in a plurality of sensors,
A portion of the abnormality detection region on the upstream side in the sheet feeding direction overlaps a part of the separation feeding region by the separation feeding unit in the sheet feeding direction,
The separation feeding means can be executed by switching between separation feeding for feeding while separating sheets and non-separation feeding for feeding without separating sheets,
The abnormality detecting means can detect skew or jam as a feeding abnormality in any case where the separation feeding means is either the separation feeding or the non-separation feeding,
The abnormality detection unit detects a feeding abnormality using a first threshold value for determining a feeding abnormality at the time of the separation feeding when the separation feeding unit is switched to the separation feeding, and the separation When the feeding means is switched to the non-separated feeding, a feeding abnormality is detected by using a second threshold value that is different from the first threshold value and for determining a feeding abnormality during the non-separating feeding. A sheet feeding apparatus characterized by: A feeding means for feeding a document;
A separating means arranged in contact with the feeding means, for separating the originals so as to feed the originals one by one;
A transport unit disposed downstream of the feeding unit in the transport direction and configured to transport a document in the transport direction;
First document detection means for detecting the position of the leading edge of the document in one region in a direction orthogonal to the transport direction among the regions around the separation unit;
A second document detection means for detecting the position of the leading edge of the document in a region opposite to the region detected by the first document detection unit;
Calculating means for calculating document conveyance information based on the position and detection timing of the leading edge of the document detected by the first document detection unit and the second document detection unit;
An abnormality determining means for determining whether or not the document feeding is abnormal based on the conveyance information calculated by the calculating means;
Changing means for changing control of document feeding when the abnormality determining means determines that the feeding is abnormal;
With
The first document detection means includes a plurality of document detection sensors arranged apart from each other in the transport direction,
The second document detection means includes a plurality of document detection sensors arranged apart from each other in the direction orthogonal to the conveyance direction with respect to each of the plurality of document detection sensors provided in the first document detection means.
The calculating means includes any one of the document detection sensors provided in the first document detection means and one document detection sensor provided in the second document detection means corresponding to the one document detection sensor. And the difference in timing when the document is detected is calculated as the skew amount of the document,
Further, the timing difference between any two of the document detection sensors provided in the first document detection means or the timing of any two of the document detection sensors provided in the second document detection means. The difference is calculated as the moving speed of the document,
The document feeding apparatus according to claim 1, wherein the abnormality determining unit determines that the feeding is abnormal when the skew amount or the moving speed calculated by the calculating unit exceeds a predetermined range. The calculation means is configured to detect two sensor pairs in which straight lines connecting sensor pairs that are pairs of the original detection sensor of the first original detection means and the original detection sensor of the second original detection means are in a substantially parallel relationship. The skew amount is calculated, and the difference between the two skew amounts is calculated as the rotation amount of the document.
13. The document feeding apparatus according to claim 12, wherein the abnormality determining unit determines that the feeding is abnormal when the rotation amount calculated by the calculating unit exceeds a specified range. The calculating means calculates the moving speed among the plurality of document detection sensors, and further calculates a difference between the two moving speeds as a speed fluctuation;
14. The document feeding apparatus according to claim 12, wherein the abnormality determining unit determines that the feeding is abnormal when the speed fluctuation exceeds a specified range. A document detection sensor that detects a document downstream of the first document detection unit and the second document detection unit and upstream of the transport unit;
The abnormality determination unit is configured to detect the document with the document detection sensor located on the most downstream side of the first document detection unit or the second document detection unit, and the rotation amount exceeds a specified range. 14. The document feeding apparatus according to claim 13, wherein if the document does not reach the document detection sensor even if the document is fed by a specified amount, it is determined that the feeding is abnormal. A document detection sensor that detects a document downstream of the first document detection unit and the second document detection unit and upstream of the transport unit;
The abnormality determining unit detects the document with the document detection sensor located on the most downstream side of the first document detection unit or the second document detection unit, and the speed fluctuation exceeds a specified range. 15. The document feeding apparatus according to claim 14, wherein if the document does not reach the document detection sensor even if the document is fed by a specified amount, it is determined that the feeding is abnormal. A non-separation mode in which the original is not separated by the separation means;
16. The document feeding apparatus according to claim 13, wherein the abnormality determination unit changes a prescribed range for determining a feeding abnormality in the non-separation mode.   Each of the first document detection unit and the second document detection unit includes three or more document detection sensors, and the abnormality determination unit defines a prescribed range for determining a feeding error in a document conveyance direction. 18. The method according to any one of claims 13 to 17, wherein a different value is set for each detection section defined between the document detection sensors arranged in a line, and further, the specified range is widened toward the upstream side in the transport direction. The document feeder described above.   The calculation unit uses only the document detection sensor that does not detect the document among the document detection sensors provided in the first document detection unit and the second document detection unit when the document feeding is started. The document feeding apparatus according to claim 13, wherein the skew feeding amount and the moving speed are calculated. Said feeding means and said separating means and Rutotomoni further comprising adjusting means for varying the contact pressure of the first document detection means and said second document sensing means, respectively provided with three or more document detection sensors The calculation means calculates the skew amount for each detection section defined between the document detection sensors arranged in the document transport direction ,
The adjusting means weakens the pressure contact force when the skew amount calculated by the calculating means exceeds a specified range, and the skew amount calculated by the calculating means in a further downstream detection section is reduced. 13. The document feeder according to claim 12 , wherein when the prescribed range is not exceeded, the pressure contact force is returned to the setting before changing.   Of the plurality of document detection sensors provided in the first document detection unit and the second document detection unit, the document detection sensor located upstream in the transport direction is connected to the nip unit between the feeding unit and the separation unit. The document feeder according to any one of claims 12 to 20, wherein the document feeder is disposed at an end portion on a downstream side of a region in which the document is fed.   An image reading apparatus comprising the sheet feeding device according to any one of claims 1 to 11 or the document feeding device according to any one of claims 12 to 21.

Images